spi: Replace `dummy.nbytes` with `dummy.ncycles`

Commit Message

Sergiu Moga Sept. 11, 2022, 5:45 p.m. UTC

In order to properly represent the hardware functionality
in the core, avoid reconverting the number of dummy cycles
to the number of bytes and only work with the former.
Instead, let the drivers that do need this conversion do
it themselves.

Signed-off-by: Sergiu Moga <[e-mail]>
---
 drivers/mtd/spi-nor/core.c        | 22 ++++----------
 drivers/mtd/spi-nor/micron-st.c   |  2 +-
 drivers/spi/atmel-quadspi.c       |  6 ++--
 drivers/spi/spi-aspeed-smc.c      | 32 ++++++++++++++-------
 drivers/spi/spi-ath79.c           |  2 +-
 drivers/spi/spi-bcm-qspi.c        | 12 +++++---
 drivers/spi/spi-cadence-quadspi.c |  8 ++----
 drivers/spi/spi-cadence-xspi.c    |  5 +++-
 drivers/spi/spi-dw-core.c         | 10 +++++--
 drivers/spi/spi-fsl-qspi.c        | 17 ++++++-----
 drivers/spi/spi-hisi-sfc-v3xx.c   |  6 +++-
 drivers/spi/spi-mem.c             | 27 +++++++++++------
 drivers/spi/spi-mt65xx.c          | 33 ++++++++++++++-------
 drivers/spi/spi-mtk-nor.c         | 48 +++++++++++++++++--------------
 drivers/spi/spi-mtk-snfi.c        | 24 ++++++++++------
 drivers/spi/spi-mxic.c            | 18 ++++++++----
 drivers/spi/spi-npcm-fiu.c        | 17 ++++++++---
 drivers/spi/spi-nxp-fspi.c        | 10 +++----
 drivers/spi/spi-rockchip-sfc.c    | 27 +++++++++++------
 drivers/spi/spi-rpc-if.c          |  5 ++--
 drivers/spi/spi-stm32-qspi.c      |  5 ++--
 drivers/spi/spi-ti-qspi.c         | 12 ++++++--
 drivers/spi/spi-zynq-qspi.c       | 15 ++++++----
 drivers/spi/spi-zynqmp-gqspi.c    |  8 ++++--
 include/linux/spi/spi-mem.h       | 10 +++----
 25 files changed, 234 insertions(+), 147 deletions(-)

Comments

Patrice CHOTARD Sept. 12, 2022, 9:44 a.m. UTC | #1

Hi Sergiu

On 9/11/22 19:45, Sergiu Moga wrote:
> In order to properly represent the hardware functionality
> in the core, avoid reconverting the number of dummy cycles
> to the number of bytes and only work with the former.
> Instead, let the drivers that do need this conversion do
> it themselves.
> 
> Signed-off-by: Sergiu Moga <[e-mail]>
> ---
>  drivers/mtd/spi-nor/core.c        | 22 ++++----------
>  drivers/mtd/spi-nor/micron-st.c   |  2 +-
>  drivers/spi/atmel-quadspi.c       |  6 ++--
>  drivers/spi/spi-aspeed-smc.c      | 32 ++++++++++++++-------
>  drivers/spi/spi-ath79.c           |  2 +-
>  drivers/spi/spi-bcm-qspi.c        | 12 +++++---
>  drivers/spi/spi-cadence-quadspi.c |  8 ++----
>  drivers/spi/spi-cadence-xspi.c    |  5 +++-
>  drivers/spi/spi-dw-core.c         | 10 +++++--
>  drivers/spi/spi-fsl-qspi.c        | 17 ++++++-----
>  drivers/spi/spi-hisi-sfc-v3xx.c   |  6 +++-
>  drivers/spi/spi-mem.c             | 27 +++++++++++------
>  drivers/spi/spi-mt65xx.c          | 33 ++++++++++++++-------
>  drivers/spi/spi-mtk-nor.c         | 48 +++++++++++++++++--------------
>  drivers/spi/spi-mtk-snfi.c        | 24 ++++++++++------
>  drivers/spi/spi-mxic.c            | 18 ++++++++----
>  drivers/spi/spi-npcm-fiu.c        | 17 ++++++++---
>  drivers/spi/spi-nxp-fspi.c        | 10 +++----
>  drivers/spi/spi-rockchip-sfc.c    | 27 +++++++++++------
>  drivers/spi/spi-rpc-if.c          |  5 ++--
>  drivers/spi/spi-stm32-qspi.c      |  5 ++--
>  drivers/spi/spi-ti-qspi.c         | 12 ++++++--
>  drivers/spi/spi-zynq-qspi.c       | 15 ++++++----
>  drivers/spi/spi-zynqmp-gqspi.c    |  8 ++++--
>  include/linux/spi/spi-mem.h       | 10 +++----
>  25 files changed, 234 insertions(+), 147 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
> index f2c64006f8d7..cc8ca824f912 100644
> --- a/drivers/mtd/spi-nor/core.c
> +++ b/drivers/mtd/spi-nor/core.c
> @@ -88,7 +88,7 @@ void spi_nor_spimem_setup_op(const struct spi_nor *nor,
>  	if (op->addr.nbytes)
>  		op->addr.buswidth = spi_nor_get_protocol_addr_nbits(proto);
>  
> -	if (op->dummy.nbytes)
> +	if (op->dummy.ncycles)
>  		op->dummy.buswidth = spi_nor_get_protocol_addr_nbits(proto);
>  
>  	if (op->data.nbytes)
> @@ -106,9 +106,6 @@ void spi_nor_spimem_setup_op(const struct spi_nor *nor,
>  		op->dummy.dtr = true;
>  		op->data.dtr = true;
>  
> -		/* 2 bytes per clock cycle in DTR mode. */
> -		op->dummy.nbytes *= 2;
> -

What is the benefit to remove dtr dummy.nbytes computation ? it leads to spray it in all drivers which support DTR.
It was simpler to let the framework to deal with it, have i missed something ?

Patrice

>  		ext = spi_nor_get_cmd_ext(nor, op);
>  		op->cmd.opcode = (op->cmd.opcode << 8) | ext;
>  		op->cmd.nbytes = 2;
> @@ -207,10 +204,7 @@ static ssize_t spi_nor_spimem_read_data(struct spi_nor *nor, loff_t from,
>  
>  	spi_nor_spimem_setup_op(nor, &op, nor->read_proto);
>  
> -	/* convert the dummy cycles to the number of bytes */
> -	op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
> -	if (spi_nor_protocol_is_dtr(nor->read_proto))
> -		op.dummy.nbytes *= 2;
> +	op.dummy.ncycles = nor->read_dummy;
>  
>  	usebouncebuf = spi_nor_spimem_bounce(nor, &op);
>  
> @@ -455,7 +449,7 @@ int spi_nor_read_sr(struct spi_nor *nor, u8 *sr)
>  
>  		if (nor->reg_proto == SNOR_PROTO_8_8_8_DTR) {
>  			op.addr.nbytes = nor->params->rdsr_addr_nbytes;
> -			op.dummy.nbytes = nor->params->rdsr_dummy;
> +			op.dummy.ncycles = nor->params->rdsr_dummy;
>  			/*
>  			 * We don't want to read only one byte in DTR mode. So,
>  			 * read 2 and then discard the second byte.
> @@ -1913,10 +1907,7 @@ static int spi_nor_spimem_check_readop(struct spi_nor *nor,
>  
>  	spi_nor_spimem_setup_op(nor, &op, read->proto);
>  
> -	/* convert the dummy cycles to the number of bytes */
> -	op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
> -	if (spi_nor_protocol_is_dtr(nor->read_proto))
> -		op.dummy.nbytes *= 2;

the same here

> +	op.dummy.ncycles = nor->read_dummy;
>  
>  	return spi_nor_spimem_check_op(nor, &op);
>  }
> @@ -3034,10 +3025,7 @@ static int spi_nor_create_read_dirmap(struct spi_nor *nor)
>  
>  	spi_nor_spimem_setup_op(nor, op, nor->read_proto);
>  
> -	/* convert the dummy cycles to the number of bytes */
> -	op->dummy.nbytes = (nor->read_dummy * op->dummy.buswidth) / 8;
> -	if (spi_nor_protocol_is_dtr(nor->read_proto))
> -		op->dummy.nbytes *= 2;

ditto

> +	op->dummy.ncycles = nor->read_dummy;
>  
>  	/*
>  	 * Since spi_nor_spimem_setup_op() only sets buswidth when the number
> diff --git a/drivers/mtd/spi-nor/micron-st.c b/drivers/mtd/spi-nor/micron-st.c
> index 3c9681a3f7a3..840a9fc0a888 100644
> --- a/drivers/mtd/spi-nor/micron-st.c
> +++ b/drivers/mtd/spi-nor/micron-st.c
> @@ -337,7 +337,7 @@ static int micron_st_nor_read_fsr(struct spi_nor *nor, u8 *fsr)
>  
>  		if (nor->reg_proto == SNOR_PROTO_8_8_8_DTR) {
>  			op.addr.nbytes = nor->params->rdsr_addr_nbytes;
> -			op.dummy.nbytes = nor->params->rdsr_dummy;
> +			op.dummy.ncycles = nor->params->rdsr_dummy;
>  			/*
>  			 * We don't want to read only one byte in DTR mode. So,
>  			 * read 2 and then discard the second byte.
> diff --git a/drivers/spi/atmel-quadspi.c b/drivers/spi/atmel-quadspi.c
> index 976a217e356d..9a86525e7a4a 100644
> --- a/drivers/spi/atmel-quadspi.c
> +++ b/drivers/spi/atmel-quadspi.c
> @@ -286,7 +286,7 @@ static bool atmel_qspi_supports_op(struct spi_mem *mem,
>  
>  	/* special case not supported by hardware */
>  	if (op->addr.nbytes == 2 && op->cmd.buswidth != op->addr.buswidth &&
> -	    op->dummy.nbytes == 0)
> +	    op->dummy.ncycles == 0)
>  		return false;
>  
>  	return true;
> @@ -308,8 +308,8 @@ static int atmel_qspi_set_cfg(struct atmel_qspi *aq,
>  		return mode;
>  	ifr |= atmel_qspi_modes[mode].config;
>  
> -	if (op->dummy.nbytes)
> -		dummy_cycles = op->dummy.nbytes * 8 / op->dummy.buswidth;
> +	if (op->dummy.ncycles)
> +		dummy_cycles = op->dummy.ncycles;
>  
>  	/*
>  	 * The controller allows 24 and 32-bit addressing while NAND-flash
> diff --git a/drivers/spi/spi-aspeed-smc.c b/drivers/spi/spi-aspeed-smc.c
> index 3e891bf22470..2d50d50a9303 100644
> --- a/drivers/spi/spi-aspeed-smc.c
> +++ b/drivers/spi/spi-aspeed-smc.c
> @@ -231,7 +231,7 @@ static ssize_t aspeed_spi_read_user(struct aspeed_spi_chip *chip,
>  				    u64 offset, size_t len, void *buf)
>  {
>  	int io_mode = aspeed_spi_get_io_mode(op);
> -	u8 dummy = 0xFF;
> +	u8 dummy = 0xFF, dummy_nbytes;
>  	int i;
>  	int ret;
>  
> @@ -241,8 +241,12 @@ static ssize_t aspeed_spi_read_user(struct aspeed_spi_chip *chip,
>  	if (ret < 0)
>  		return ret;
>  
> -	if (op->dummy.buswidth && op->dummy.nbytes) {
> -		for (i = 0; i < op->dummy.nbytes / op->dummy.buswidth; i++)
> +	if (op->dummy.buswidth && op->dummy.ncycles) {
> +		dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +		if (op->dummy.dtr)
> +			dummy_nbytes *= 2;
> +
> +		for (i = 0; i < dummy_nbytes / op->dummy.buswidth; i++)
>  			aspeed_spi_write_to_ahb(chip->ahb_base, &dummy,	sizeof(dummy));
>  	}
>  
> @@ -270,6 +274,8 @@ static ssize_t aspeed_spi_write_user(struct aspeed_spi_chip *chip,
>  /* support for 1-1-1, 1-1-2 or 1-1-4 */
>  static bool aspeed_spi_supports_op(struct spi_mem *mem, const struct spi_mem_op *op)
>  {
> +	u8 dummy_nbytes;
> +
>  	if (op->cmd.buswidth > 1)
>  		return false;
>  
> @@ -280,8 +286,12 @@ static bool aspeed_spi_supports_op(struct spi_mem *mem, const struct spi_mem_op
>  			return false;
>  	}
>  
> -	if (op->dummy.nbytes != 0) {
> -		if (op->dummy.buswidth > 1 || op->dummy.nbytes > 7)
> +	if (op->dummy.ncycles != 0) {
> +		dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +		if (op->dummy.dtr)
> +			dummy_nbytes *= 2;
> +
> +		if (op->dummy.buswidth > 1 || dummy_nbytes > 7)
>  			return false;
>  	}
>  
> @@ -306,7 +316,7 @@ static int do_aspeed_spi_exec_op(struct spi_mem *mem, const struct spi_mem_op *o
>  		chip->cs, op->data.dir == SPI_MEM_DATA_IN ? "read" : "write",
>  		op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
>  		op->dummy.buswidth, op->data.buswidth,
> -		op->addr.nbytes, op->dummy.nbytes, op->data.nbytes);
> +		op->addr.nbytes, op->dummy.ncycles, op->data.nbytes);
>  
>  	addr_mode = readl(aspi->regs + CE_CTRL_REG);
>  	addr_mode_backup = addr_mode;
> @@ -327,8 +337,8 @@ static int do_aspeed_spi_exec_op(struct spi_mem *mem, const struct spi_mem_op *o
>  			ctl_val |= CTRL_IO_ADDRESS_4B;
>  	}
>  
> -	if (op->dummy.nbytes)
> -		ctl_val |= CTRL_IO_DUMMY_SET(op->dummy.nbytes / op->dummy.buswidth);
> +	if (op->dummy.ncycles)
> +		ctl_val |= CTRL_IO_DUMMY_SET(op->dummy.ncycles / 8);
>  
>  	if (op->data.nbytes)
>  		ctl_val |= aspeed_spi_get_io_mode(op);
> @@ -564,7 +574,7 @@ static int aspeed_spi_dirmap_create(struct spi_mem_dirmap_desc *desc)
>  		desc->info.offset, desc->info.offset + desc->info.length,
>  		op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
>  		op->dummy.buswidth, op->data.buswidth,
> -		op->addr.nbytes, op->dummy.nbytes);
> +		op->addr.nbytes, op->dummy.ncycles);
>  
>  	chip->clk_freq = desc->mem->spi->max_speed_hz;
>  
> @@ -584,8 +594,8 @@ static int aspeed_spi_dirmap_create(struct spi_mem_dirmap_desc *desc)
>  		op->cmd.opcode << CTRL_COMMAND_SHIFT |
>  		CTRL_IO_MODE_READ;
>  
> -	if (op->dummy.nbytes)
> -		ctl_val |= CTRL_IO_DUMMY_SET(op->dummy.nbytes / op->dummy.buswidth);
> +	if (op->dummy.ncycles)
> +		ctl_val |= CTRL_IO_DUMMY_SET(op->dummy.ncycles / 8);
>  
>  	/* Tune 4BYTE address mode */
>  	if (op->addr.nbytes) {
> diff --git a/drivers/spi/spi-ath79.c b/drivers/spi/spi-ath79.c
> index 607e7a49fb89..70bdb1eb42a2 100644
> --- a/drivers/spi/spi-ath79.c
> +++ b/drivers/spi/spi-ath79.c
> @@ -145,7 +145,7 @@ static int ath79_exec_mem_op(struct spi_mem *mem,
>  
>  	/* Only use for fast-read op. */
>  	if (op->cmd.opcode != 0x0b || op->data.dir != SPI_MEM_DATA_IN ||
> -	    op->addr.nbytes != 3 || op->dummy.nbytes != 1)
> +	    op->addr.nbytes != 3 || op->dummy.ncycles != 8)
>  		return -ENOTSUPP;
>  
>  	/* disable GPIO mode */
> diff --git a/drivers/spi/spi-bcm-qspi.c b/drivers/spi/spi-bcm-qspi.c
> index cad2d55dcd3d..143e411c1523 100644
> --- a/drivers/spi/spi-bcm-qspi.c
> +++ b/drivers/spi/spi-bcm-qspi.c
> @@ -428,8 +428,8 @@ static int bcm_qspi_bspi_set_flex_mode(struct bcm_qspi *qspi,
>  	if (addrlen == BSPI_ADDRLEN_4BYTES)
>  		bpp = BSPI_BPP_ADDR_SELECT_MASK;
>  
> -	if (op->dummy.nbytes)
> -		bpp |= (op->dummy.nbytes * 8) / op->dummy.buswidth;
> +	if (op->dummy.ncycles)
> +		bpp |= op->dummy.ncycles;
>  
>  	switch (width) {
>  	case SPI_NBITS_SINGLE:
> @@ -1153,12 +1153,16 @@ static int bcm_qspi_mspi_exec_mem_op(struct spi_device *spi,
>  	struct spi_master *master = spi->master;
>  	struct bcm_qspi *qspi = spi_master_get_devdata(master);
>  	struct spi_transfer t[2];
> -	u8 cmd[6] = { };
> +	u8 cmd[6] = { }, dummy_nbytes;
>  	int ret, i;
>  
>  	memset(cmd, 0, sizeof(cmd));
>  	memset(t, 0, sizeof(t));
>  
> +	dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
> +
>  	/* tx */
>  	/* opcode is in cmd[0] */
>  	cmd[0] = op->cmd.opcode;
> @@ -1166,7 +1170,7 @@ static int bcm_qspi_mspi_exec_mem_op(struct spi_device *spi,
>  		cmd[1 + i] = op->addr.val >> (8 * (op->addr.nbytes - i - 1));
>  
>  	t[0].tx_buf = cmd;
> -	t[0].len = op->addr.nbytes + op->dummy.nbytes + 1;
> +	t[0].len = op->addr.nbytes + dummy_nbytes + 1;
>  	t[0].bits_per_word = spi->bits_per_word;
>  	t[0].tx_nbits = op->cmd.buswidth;
>  	/* lets mspi know that this is not last transfer */
> diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c
> index 72b1a5a2298c..2af43ba4a2cb 100644
> --- a/drivers/spi/spi-cadence-quadspi.c
> +++ b/drivers/spi/spi-cadence-quadspi.c
> @@ -356,12 +356,10 @@ static unsigned int cqspi_calc_dummy(const struct spi_mem_op *op)
>  {
>  	unsigned int dummy_clk;
>  
> -	if (!op->dummy.nbytes)
> +	if (!op->dummy.ncycles)
>  		return 0;
>  
> -	dummy_clk = op->dummy.nbytes * (8 / op->dummy.buswidth);
> -	if (op->cmd.dtr)
> -		dummy_clk /= 2;
> +	dummy_clk = op->dummy.ncycles;
>  
>  	return dummy_clk;
>  }
> @@ -1333,7 +1331,7 @@ static bool cqspi_supports_mem_op(struct spi_mem *mem,
>  	 */
>  	all_true = op->cmd.dtr &&
>  		   (!op->addr.nbytes || op->addr.dtr) &&
> -		   (!op->dummy.nbytes || op->dummy.dtr) &&
> +		   (!op->dummy.ncycles || op->dummy.dtr) &&
>  		   (!op->data.nbytes || op->data.dtr);
>  
>  	all_false = !op->cmd.dtr && !op->addr.dtr && !op->dummy.dtr &&
> diff --git a/drivers/spi/spi-cadence-xspi.c b/drivers/spi/spi-cadence-xspi.c
> index 3ab19be83095..8575e4c2ed7a 100644
> --- a/drivers/spi/spi-cadence-xspi.c
> +++ b/drivers/spi/spi-cadence-xspi.c
> @@ -177,7 +177,10 @@
>  #define CDNS_XSPI_CMD_FLD_DSEQ_CMD_3(op) ( \
>  	FIELD_PREP(CDNS_XSPI_CMD_DSEQ_R3_DCNT_H, \
>  		((op)->data.nbytes >> 16) & 0xffff) | \
> -	FIELD_PREP(CDNS_XSPI_CMD_DSEQ_R3_NUM_OF_DUMMY, (op)->dummy.nbytes * 8))
> +	FIELD_PREP(CDNS_XSPI_CMD_DSEQ_R3_NUM_OF_DUMMY, \
> +		((op)->dummy.dtr ? \
> +		((op)->dummy.ncycles * (op)->dummy.buswidth * 2) : \
> +		((op)->dummy.ncycles * (op)->dummy.buswidth))))
>  
>  #define CDNS_XSPI_CMD_FLD_DSEQ_CMD_4(op, chipsel) ( \
>  	FIELD_PREP(CDNS_XSPI_CMD_DSEQ_R4_BANK, chipsel) | \
> diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c
> index f87d97ccd2d6..0ba5c7d0e66e 100644
> --- a/drivers/spi/spi-dw-core.c
> +++ b/drivers/spi/spi-dw-core.c
> @@ -498,13 +498,17 @@ static bool dw_spi_supports_mem_op(struct spi_mem *mem,
>  static int dw_spi_init_mem_buf(struct dw_spi *dws, const struct spi_mem_op *op)
>  {
>  	unsigned int i, j, len;
> -	u8 *out;
> +	u8 *out, dummy_nbytes;
>  
>  	/*
>  	 * Calculate the total length of the EEPROM command transfer and
>  	 * either use the pre-allocated buffer or create a temporary one.
>  	 */
> -	len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
> +	dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
> +
> +	len = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes;
>  	if (op->data.dir == SPI_MEM_DATA_OUT)
>  		len += op->data.nbytes;
>  
> @@ -525,7 +529,7 @@ static int dw_spi_init_mem_buf(struct dw_spi *dws, const struct spi_mem_op *op)
>  		out[i] = DW_SPI_GET_BYTE(op->cmd.opcode, op->cmd.nbytes - i - 1);
>  	for (j = 0; j < op->addr.nbytes; ++i, ++j)
>  		out[i] = DW_SPI_GET_BYTE(op->addr.val, op->addr.nbytes - j - 1);
> -	for (j = 0; j < op->dummy.nbytes; ++i, ++j)
> +	for (j = 0; j < dummy_nbytes; ++i, ++j)
>  		out[i] = 0x0;
>  
>  	if (op->data.dir == SPI_MEM_DATA_OUT)
> diff --git a/drivers/spi/spi-fsl-qspi.c b/drivers/spi/spi-fsl-qspi.c
> index 46ae46a944c5..897e8f11ccd1 100644
> --- a/drivers/spi/spi-fsl-qspi.c
> +++ b/drivers/spi/spi-fsl-qspi.c
> @@ -369,6 +369,7 @@ static bool fsl_qspi_supports_op(struct spi_mem *mem,
>  				 const struct spi_mem_op *op)
>  {
>  	struct fsl_qspi *q = spi_controller_get_devdata(mem->spi->master);
> +	u8 dummy_nbytes;
>  	int ret;
>  
>  	ret = fsl_qspi_check_buswidth(q, op->cmd.buswidth);
> @@ -376,7 +377,7 @@ static bool fsl_qspi_supports_op(struct spi_mem *mem,
>  	if (op->addr.nbytes)
>  		ret |= fsl_qspi_check_buswidth(q, op->addr.buswidth);
>  
> -	if (op->dummy.nbytes)
> +	if (op->dummy.ncycles)
>  		ret |= fsl_qspi_check_buswidth(q, op->dummy.buswidth);
>  
>  	if (op->data.nbytes)
> @@ -389,14 +390,17 @@ static bool fsl_qspi_supports_op(struct spi_mem *mem,
>  	 * The number of instructions needed for the op, needs
>  	 * to fit into a single LUT entry.
>  	 */
> +	dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
> +
>  	if (op->addr.nbytes +
> -	   (op->dummy.nbytes ? 1:0) +
> +	   (dummy_nbytes ? 1:0) +
>  	   (op->data.nbytes ? 1:0) > 6)
>  		return false;
>  
>  	/* Max 64 dummy clock cycles supported */
> -	if (op->dummy.nbytes &&
> -	    (op->dummy.nbytes * 8 / op->dummy.buswidth > 64))
> +	if (op->dummy.ncycles && op->dummy.ncycles > 64)
>  		return false;
>  
>  	/* Max data length, check controller limits and alignment */
> @@ -437,11 +441,10 @@ static void fsl_qspi_prepare_lut(struct fsl_qspi *q,
>  		lutidx++;
>  	}
>  
> -	if (op->dummy.nbytes) {
> +	if (op->dummy.ncycles) {
>  		lutval[lutidx / 2] |= LUT_DEF(lutidx, LUT_DUMMY,
>  					      LUT_PAD(op->dummy.buswidth),
> -					      op->dummy.nbytes * 8 /
> -					      op->dummy.buswidth);
> +					      op->dummy.ncycles);
>  		lutidx++;
>  	}
>  
> diff --git a/drivers/spi/spi-hisi-sfc-v3xx.c b/drivers/spi/spi-hisi-sfc-v3xx.c
> index d3a23b1c2a4c..5b6994eb7c8b 100644
> --- a/drivers/spi/spi-hisi-sfc-v3xx.c
> +++ b/drivers/spi/spi-hisi-sfc-v3xx.c
> @@ -276,6 +276,7 @@ static int hisi_sfc_v3xx_start_bus(struct hisi_sfc_v3xx_host *host,
>  {
>  	int len = op->data.nbytes, buswidth_mode;
>  	u32 config = 0;
> +	u8 dummy_nbytes;
>  
>  	if (op->addr.nbytes)
>  		config |= HISI_SFC_V3XX_CMD_CFG_ADDR_EN_MSK;
> @@ -302,7 +303,10 @@ static int hisi_sfc_v3xx_start_bus(struct hisi_sfc_v3xx_host *host,
>  	if (op->data.dir == SPI_MEM_DATA_IN)
>  		config |= HISI_SFC_V3XX_CMD_CFG_RW_MSK;
>  
> -	config |= op->dummy.nbytes << HISI_SFC_V3XX_CMD_CFG_DUMMY_CNT_OFF |
> +	dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
> +	config |= dummy_nbytes << HISI_SFC_V3XX_CMD_CFG_DUMMY_CNT_OFF |
>  		  chip_select << HISI_SFC_V3XX_CMD_CFG_CS_SEL_OFF |
>  		  HISI_SFC_V3XX_CMD_CFG_START_MSK;
>  
> diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
> index 0c79193d9697..7b204963bb62 100644
> --- a/drivers/spi/spi-mem.c
> +++ b/drivers/spi/spi-mem.c
> @@ -149,7 +149,7 @@ static bool spi_mem_check_buswidth(struct spi_mem *mem,
>  	    spi_check_buswidth_req(mem, op->addr.buswidth, true))
>  		return false;
>  
> -	if (op->dummy.nbytes &&
> +	if (op->dummy.ncycles &&
>  	    spi_check_buswidth_req(mem, op->dummy.buswidth, true))
>  		return false;
>  
> @@ -202,7 +202,7 @@ static int spi_mem_check_op(const struct spi_mem_op *op)
>  		return -EINVAL;
>  
>  	if ((op->addr.nbytes && !op->addr.buswidth) ||
> -	    (op->dummy.nbytes && !op->dummy.buswidth) ||
> +	    (op->dummy.ncycles && !op->dummy.buswidth) ||
>  	    (op->data.nbytes && !op->data.buswidth))
>  		return -EINVAL;
>  
> @@ -315,7 +315,7 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
>  	struct spi_controller *ctlr = mem->spi->controller;
>  	struct spi_transfer xfers[4] = { };
>  	struct spi_message msg;
> -	u8 *tmpbuf;
> +	u8 *tmpbuf, dummy_nbytes;
>  	int ret;
>  
>  	ret = spi_mem_check_op(op);
> @@ -343,7 +343,11 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
>  			return ret;
>  	}
>  
> -	tmpbufsize = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
> +	dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
> +
> +	tmpbufsize = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes;
>  
>  	/*
>  	 * Allocate a buffer to transmit the CMD, ADDR cycles with kmalloc() so
> @@ -379,15 +383,15 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
>  		totalxferlen += op->addr.nbytes;
>  	}
>  
> -	if (op->dummy.nbytes) {
> -		memset(tmpbuf + op->addr.nbytes + 1, 0xff, op->dummy.nbytes);
> +	if (dummy_nbytes) {
> +		memset(tmpbuf + op->addr.nbytes + 1, 0xff, dummy_nbytes);
>  		xfers[xferpos].tx_buf = tmpbuf + op->addr.nbytes + 1;
> -		xfers[xferpos].len = op->dummy.nbytes;
> +		xfers[xferpos].len = dummy_nbytes;
>  		xfers[xferpos].tx_nbits = op->dummy.buswidth;
>  		xfers[xferpos].dummy_data = 1;
>  		spi_message_add_tail(&xfers[xferpos], &msg);
>  		xferpos++;
> -		totalxferlen += op->dummy.nbytes;
> +		totalxferlen += dummy_nbytes;
>  	}
>  
>  	if (op->data.nbytes) {
> @@ -456,12 +460,17 @@ int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
>  {
>  	struct spi_controller *ctlr = mem->spi->controller;
>  	size_t len;
> +	u8 dummy_nbytes;
>  
>  	if (ctlr->mem_ops && ctlr->mem_ops->adjust_op_size)
>  		return ctlr->mem_ops->adjust_op_size(mem, op);
>  
> +	dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
> +
>  	if (!ctlr->mem_ops || !ctlr->mem_ops->exec_op) {
> -		len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
> +		len = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes;
>  
>  		if (len > spi_max_transfer_size(mem->spi))
>  			return -EINVAL;
> diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c
> index 0a3b9f7eed30..22d002acebe8 100644
> --- a/drivers/spi/spi-mt65xx.c
> +++ b/drivers/spi/spi-mt65xx.c
> @@ -845,9 +845,13 @@ static int mtk_spi_mem_adjust_op_size(struct spi_mem *mem,
>  				      struct spi_mem_op *op)
>  {
>  	int opcode_len;
> +	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
>  
>  	if (op->data.dir != SPI_MEM_NO_DATA) {
> -		opcode_len = 1 + op->addr.nbytes + op->dummy.nbytes;
> +		opcode_len = 1 + op->addr.nbytes + dummy_nbytes;
>  		if (opcode_len + op->data.nbytes > MTK_SPI_IPM_PACKET_SIZE) {
>  			op->data.nbytes = MTK_SPI_IPM_PACKET_SIZE - opcode_len;
>  			/* force data buffer dma-aligned. */
> @@ -861,14 +865,19 @@ static int mtk_spi_mem_adjust_op_size(struct spi_mem *mem,
>  static bool mtk_spi_mem_supports_op(struct spi_mem *mem,
>  				    const struct spi_mem_op *op)
>  {
> +	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
> +
>  	if (!spi_mem_default_supports_op(mem, op))
>  		return false;
>  
> -	if (op->addr.nbytes && op->dummy.nbytes &&
> +	if (op->addr.nbytes && dummy_nbytes &&
>  	    op->addr.buswidth != op->dummy.buswidth)
>  		return false;
>  
> -	if (op->addr.nbytes + op->dummy.nbytes > 16)
> +	if (op->addr.nbytes + dummy_nbytes > 16)
>  		return false;
>  
>  	if (op->data.nbytes > MTK_SPI_IPM_PACKET_SIZE) {
> @@ -942,6 +951,10 @@ static int mtk_spi_mem_exec_op(struct spi_mem *mem,
>  	u32 reg_val, nio, tx_size;
>  	char *tx_tmp_buf, *rx_tmp_buf;
>  	int ret = 0;
> +	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
>  
>  	mdata->use_spimem = true;
>  	reinit_completion(&mdata->spimem_done);
> @@ -957,8 +970,8 @@ static int mtk_spi_mem_exec_op(struct spi_mem *mem,
>  
>  	/* addr & dummy byte len */
>  	reg_val &= ~SPI_CFG3_IPM_ADDR_BYTELEN_MASK;
> -	if (op->addr.nbytes || op->dummy.nbytes)
> -		reg_val |= (op->addr.nbytes + op->dummy.nbytes) <<
> +	if (op->addr.nbytes || dummy_nbytes)
> +		reg_val |= (op->addr.nbytes + dummy_nbytes) <<
>  			    SPI_CFG3_IPM_ADDR_BYTELEN_OFFSET;
>  
>  	/* data byte len */
> @@ -971,7 +984,7 @@ static int mtk_spi_mem_exec_op(struct spi_mem *mem,
>  		mtk_spi_setup_packet(mem->spi->master);
>  	}
>  
> -	if (op->addr.nbytes || op->dummy.nbytes) {
> +	if (op->addr.nbytes || dummy_nbytes) {
>  		if (op->addr.buswidth == 1 || op->dummy.buswidth == 1)
>  			reg_val |= SPI_CFG3_IPM_XMODE_EN;
>  		else
> @@ -999,7 +1012,7 @@ static int mtk_spi_mem_exec_op(struct spi_mem *mem,
>  		reg_val &= ~SPI_CFG3_IPM_HALF_DUPLEX_DIR;
>  	writel(reg_val, mdata->base + SPI_CFG3_IPM_REG);
>  
> -	tx_size = 1 + op->addr.nbytes + op->dummy.nbytes;
> +	tx_size = 1 + op->addr.nbytes + dummy_nbytes;
>  	if (op->data.dir == SPI_MEM_DATA_OUT)
>  		tx_size += op->data.nbytes;
>  
> @@ -1021,13 +1034,13 @@ static int mtk_spi_mem_exec_op(struct spi_mem *mem,
>  					(8 * (op->addr.nbytes - i - 1));
>  	}
>  
> -	if (op->dummy.nbytes)
> +	if (dummy_nbytes)
>  		memset(tx_tmp_buf + op->addr.nbytes + 1,
>  		       0xff,
> -		       op->dummy.nbytes);
> +		       dummy_nbytes);
>  
>  	if (op->data.nbytes && op->data.dir == SPI_MEM_DATA_OUT)
> -		memcpy(tx_tmp_buf + op->dummy.nbytes + op->addr.nbytes + 1,
> +		memcpy(tx_tmp_buf + dummy_nbytes + op->addr.nbytes + 1,
>  		       op->data.buf.out,
>  		       op->data.nbytes);
>  
> diff --git a/drivers/spi/spi-mtk-nor.c b/drivers/spi/spi-mtk-nor.c
> index d167699a1a96..f6870c6e911a 100644
> --- a/drivers/spi/spi-mtk-nor.c
> +++ b/drivers/spi/spi-mtk-nor.c
> @@ -171,23 +171,18 @@ static bool need_bounce(struct mtk_nor *sp, const struct spi_mem_op *op)
>  
>  static bool mtk_nor_match_read(const struct spi_mem_op *op)
>  {
> -	int dummy = 0;
> -
> -	if (op->dummy.nbytes)
> -		dummy = op->dummy.nbytes * BITS_PER_BYTE / op->dummy.buswidth;
> -
>  	if ((op->data.buswidth == 2) || (op->data.buswidth == 4)) {
>  		if (op->addr.buswidth == 1)
> -			return dummy == 8;
> +			return op->dummy.ncycles == 8;
>  		else if (op->addr.buswidth == 2)
> -			return dummy == 4;
> +			return op->dummy.ncycles == 4;
>  		else if (op->addr.buswidth == 4)
> -			return dummy == 6;
> +			return op->dummy.ncycles == 6;
>  	} else if ((op->addr.buswidth == 1) && (op->data.buswidth == 1)) {
>  		if (op->cmd.opcode == 0x03)
> -			return dummy == 0;
> +			return op->dummy.ncycles == 0;
>  		else if (op->cmd.opcode == 0x0b)
> -			return dummy == 8;
> +			return op->dummy.ncycles == 8;
>  	}
>  	return false;
>  }
> @@ -195,6 +190,10 @@ static bool mtk_nor_match_read(const struct spi_mem_op *op)
>  static bool mtk_nor_match_prg(const struct spi_mem_op *op)
>  {
>  	int tx_len, rx_len, prg_len, prg_left;
> +	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
>  
>  	// prg mode is spi-only.
>  	if ((op->cmd.buswidth > 1) || (op->addr.buswidth > 1) ||
> @@ -205,7 +204,7 @@ static bool mtk_nor_match_prg(const struct spi_mem_op *op)
>  
>  	if (op->data.dir == SPI_MEM_DATA_OUT) {
>  		// count dummy bytes only if we need to write data after it
> -		tx_len += op->dummy.nbytes;
> +		tx_len += dummy_nbytes;
>  
>  		// leave at least one byte for data
>  		if (tx_len > MTK_NOR_REG_PRGDATA_MAX)
> @@ -221,7 +220,7 @@ static bool mtk_nor_match_prg(const struct spi_mem_op *op)
>  			return false;
>  
>  		rx_len = op->data.nbytes;
> -		prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - op->dummy.nbytes;
> +		prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - dummy_nbytes;
>  		if (prg_left > MTK_NOR_REG_SHIFT_MAX + 1)
>  			prg_left = MTK_NOR_REG_SHIFT_MAX + 1;
>  		if (rx_len > prg_left) {
> @@ -230,11 +229,11 @@ static bool mtk_nor_match_prg(const struct spi_mem_op *op)
>  			rx_len = prg_left;
>  		}
>  
> -		prg_len = tx_len + op->dummy.nbytes + rx_len;
> +		prg_len = tx_len + dummy_nbytes + rx_len;
>  		if (prg_len > MTK_NOR_PRG_CNT_MAX / 8)
>  			return false;
>  	} else {
> -		prg_len = tx_len + op->dummy.nbytes;
> +		prg_len = tx_len + dummy_nbytes;
>  		if (prg_len > MTK_NOR_PRG_CNT_MAX / 8)
>  			return false;
>  	}
> @@ -244,15 +243,19 @@ static bool mtk_nor_match_prg(const struct spi_mem_op *op)
>  static void mtk_nor_adj_prg_size(struct spi_mem_op *op)
>  {
>  	int tx_len, tx_left, prg_left;
> +	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
>  
>  	tx_len = op->cmd.nbytes + op->addr.nbytes;
>  	if (op->data.dir == SPI_MEM_DATA_OUT) {
> -		tx_len += op->dummy.nbytes;
> +		tx_len += dummy_nbytes;
>  		tx_left = MTK_NOR_REG_PRGDATA_MAX + 1 - tx_len;
>  		if (op->data.nbytes > tx_left)
>  			op->data.nbytes = tx_left;
>  	} else if (op->data.dir == SPI_MEM_DATA_IN) {
> -		prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - op->dummy.nbytes;
> +		prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - dummy_nbytes;
>  		if (prg_left > MTK_NOR_REG_SHIFT_MAX + 1)
>  			prg_left = MTK_NOR_REG_SHIFT_MAX + 1;
>  		if (op->data.nbytes > prg_left)
> @@ -312,7 +315,7 @@ static bool mtk_nor_supports_op(struct spi_mem *mem,
>  			break;
>  		case SPI_MEM_DATA_OUT:
>  			if ((op->addr.buswidth == 1) &&
> -			    (op->dummy.nbytes == 0) &&
> +			    (op->dummy.ncycles == 0) &&
>  			    (op->data.buswidth == 1))
>  				return true;
>  			break;
> @@ -515,17 +518,20 @@ static int mtk_nor_spi_mem_prg(struct mtk_nor *sp, const struct spi_mem_op *op)
>  	int tx_len, prg_len;
>  	int i, ret;
>  	void __iomem *reg;
> -	u8 bufbyte;
> +	u8 bufbyte, dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
>  
>  	tx_len = op->cmd.nbytes + op->addr.nbytes;
>  
>  	// count dummy bytes only if we need to write data after it
>  	if (op->data.dir == SPI_MEM_DATA_OUT)
> -		tx_len += op->dummy.nbytes + op->data.nbytes;
> +		tx_len += dummy_nbytes + op->data.nbytes;
>  	else if (op->data.dir == SPI_MEM_DATA_IN)
>  		rx_len = op->data.nbytes;
>  
> -	prg_len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes +
> +	prg_len = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes +
>  		  op->data.nbytes;
>  
>  	// an invalid op may reach here if the caller calls exec_op without
> @@ -550,7 +556,7 @@ static int mtk_nor_spi_mem_prg(struct mtk_nor *sp, const struct spi_mem_op *op)
>  	}
>  
>  	if (op->data.dir == SPI_MEM_DATA_OUT) {
> -		for (i = 0; i < op->dummy.nbytes; i++, reg_offset--) {
> +		for (i = 0; i < dummy_nbytes; i++, reg_offset--) {
>  			reg = sp->base + MTK_NOR_REG_PRGDATA(reg_offset);
>  			writeb(0, reg);
>  		}
> diff --git a/drivers/spi/spi-mtk-snfi.c b/drivers/spi/spi-mtk-snfi.c
> index d66bf9762557..05d2f0a97feb 100644
> --- a/drivers/spi/spi-mtk-snfi.c
> +++ b/drivers/spi/spi-mtk-snfi.c
> @@ -434,7 +434,10 @@ static int mtk_snand_mac_io(struct mtk_snand *snf, const struct spi_mem_op *op)
>  	const u8 *tx_buf = NULL;
>  	u8 *rx_buf = NULL;
>  	int i, ret;
> -	u8 b;
> +	u8 b, dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
>  
>  	if (op->data.dir == SPI_MEM_DATA_IN) {
>  		rx_len = op->data.nbytes;
> @@ -463,7 +466,7 @@ static int mtk_snand_mac_io(struct mtk_snand *snf, const struct spi_mem_op *op)
>  		}
>  	}
>  
> -	for (i = 0; i < op->dummy.nbytes; i++, reg_offs++) {
> +	for (i = 0; i < dummy_nbytes; i++, reg_offs++) {
>  		if (reg_offs % 4 == 3) {
>  			nfi_write32(snf, SNF_GPRAM + reg_offs - 3, val);
>  			val = 0;
> @@ -836,7 +839,7 @@ static int mtk_snand_read_page_cache(struct mtk_snand *snf,
>  	u32 op_addr = op->addr.val;
>  	// where to start copying data from bounce buffer
>  	u32 rd_offset = 0;
> -	u32 dummy_clk = (op->dummy.nbytes * BITS_PER_BYTE / op->dummy.buswidth);
> +	u32 dummy_clk = op->dummy.ncycles;
>  	u32 op_mode = 0;
>  	u32 dma_len = snf->buf_len;
>  	int ret = 0;
> @@ -1178,8 +1181,7 @@ static bool mtk_snand_is_page_ops(const struct spi_mem_op *op)
>  	// match read from page instructions
>  	if (op->data.dir == SPI_MEM_DATA_IN) {
>  		// check dummy cycle first
> -		if (op->dummy.nbytes * BITS_PER_BYTE / op->dummy.buswidth >
> -		    DATA_READ_MAX_DUMMY)
> +		if (op->dummy.ncycles > DATA_READ_MAX_DUMMY)
>  			return false;
>  		// quad io / quad out
>  		if ((op->addr.buswidth == 4 || op->addr.buswidth == 1) &&
> @@ -1196,7 +1198,7 @@ static bool mtk_snand_is_page_ops(const struct spi_mem_op *op)
>  			return true;
>  	} else if (op->data.dir == SPI_MEM_DATA_OUT) {
>  		// check dummy cycle first
> -		if (op->dummy.nbytes)
> +		if (op->dummy.ncycles)
>  			return false;
>  		// program load quad out
>  		if (op->addr.buswidth == 1 && op->data.buswidth == 4)
> @@ -1218,7 +1220,7 @@ static bool mtk_snand_supports_op(struct spi_mem *mem,
>  	if (mtk_snand_is_page_ops(op))
>  		return true;
>  	return ((op->addr.nbytes == 0 || op->addr.buswidth == 1) &&
> -		(op->dummy.nbytes == 0 || op->dummy.buswidth == 1) &&
> +		(op->dummy.ncycles == 0 || op->dummy.buswidth == 1) &&
>  		(op->data.nbytes == 0 || op->data.buswidth == 1));
>  }
>  
> @@ -1239,7 +1241,13 @@ static int mtk_snand_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
>  		if (op->data.nbytes > l)
>  			op->data.nbytes = l;
>  	} else {
> -		size_t hl = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
> +		size_t hl;
> +		u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +
> +		if (op->dummy.dtr)
> +			dummy_nbytes *= 2;
> +
> +		hl = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes;
>  
>  		if (hl >= SNF_GPRAM_SIZE)
>  			return -EOPNOTSUPP;
> diff --git a/drivers/spi/spi-mxic.c b/drivers/spi/spi-mxic.c
> index 65be8e085ab8..d940ee0e11a5 100644
> --- a/drivers/spi/spi-mxic.c
> +++ b/drivers/spi/spi-mxic.c
> @@ -316,14 +316,18 @@ static u32 mxic_spi_mem_prep_op_cfg(const struct spi_mem_op *op,
>  	u32 cfg = OP_CMD_BYTES(op->cmd.nbytes) |
>  		  OP_CMD_BUSW(fls(op->cmd.buswidth) - 1) |
>  		  (op->cmd.dtr ? OP_CMD_DDR : 0);
> +	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
>  
>  	if (op->addr.nbytes)
>  		cfg |= OP_ADDR_BYTES(op->addr.nbytes) |
>  		       OP_ADDR_BUSW(fls(op->addr.buswidth) - 1) |
>  		       (op->addr.dtr ? OP_ADDR_DDR : 0);
>  
> -	if (op->dummy.nbytes)
> -		cfg |= OP_DUMMY_CYC(op->dummy.nbytes);
> +	if (dummy_nbytes)
> +		cfg |= OP_DUMMY_CYC(dummy_nbytes);
>  
>  	/* Direct mapping data.nbytes field is not populated */
>  	if (data_len) {
> @@ -481,7 +485,7 @@ static bool mxic_spi_mem_supports_op(struct spi_mem *mem,
>  	    op->dummy.buswidth > 8 || op->cmd.buswidth > 8)
>  		return false;
>  
> -	if (op->data.nbytes && op->dummy.nbytes &&
> +	if (op->data.nbytes && op->dummy.ncycles &&
>  	    op->data.buswidth != op->dummy.buswidth)
>  		return false;
>  
> @@ -512,7 +516,11 @@ static int mxic_spi_mem_exec_op(struct spi_mem *mem,
>  {
>  	struct mxic_spi *mxic = spi_master_get_devdata(mem->spi->master);
>  	int i, ret;
> -	u8 addr[8], cmd[2];
> +	u8 addr[8], cmd[2], dummy_nbytes;
> +
> +	dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
>  
>  	ret = mxic_spi_set_freq(mxic, mem->spi->max_speed_hz);
>  	if (ret)
> @@ -543,7 +551,7 @@ static int mxic_spi_mem_exec_op(struct spi_mem *mem,
>  	if (ret)
>  		goto out;
>  
> -	ret = mxic_spi_data_xfer(mxic, NULL, NULL, op->dummy.nbytes);
> +	ret = mxic_spi_data_xfer(mxic, NULL, NULL, dummy_nbytes);
>  	if (ret)
>  		goto out;
>  
> diff --git a/drivers/spi/spi-npcm-fiu.c b/drivers/spi/spi-npcm-fiu.c
> index 49f6424e35af..17493f668459 100644
> --- a/drivers/spi/spi-npcm-fiu.c
> +++ b/drivers/spi/spi-npcm-fiu.c
> @@ -265,6 +265,11 @@ static const struct regmap_config npcm_mtd_regmap_config = {
>  static void npcm_fiu_set_drd(struct npcm_fiu_spi *fiu,
>  			     const struct spi_mem_op *op)
>  {
> +	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
> +
>  	regmap_update_bits(fiu->regmap, NPCM_FIU_DRD_CFG,
>  			   NPCM_FIU_DRD_CFG_ACCTYPE,
>  			   ilog2(op->addr.buswidth) <<
> @@ -272,8 +277,8 @@ static void npcm_fiu_set_drd(struct npcm_fiu_spi *fiu,
>  	fiu->drd_op.addr.buswidth = op->addr.buswidth;
>  	regmap_update_bits(fiu->regmap, NPCM_FIU_DRD_CFG,
>  			   NPCM_FIU_DRD_CFG_DBW,
> -			   op->dummy.nbytes << NPCM_FIU_DRD_DBW_SHIFT);
> -	fiu->drd_op.dummy.nbytes = op->dummy.nbytes;
> +			   dummy_nbytes << NPCM_FIU_DRD_DBW_SHIFT);
> +	fiu->drd_op.dummy.ncycles = op->dummy.ncycles;
>  	regmap_update_bits(fiu->regmap, NPCM_FIU_DRD_CFG,
>  			   NPCM_FIU_DRD_CFG_RDCMD, op->cmd.opcode);
>  	fiu->drd_op.cmd.opcode = op->cmd.opcode;
> @@ -299,7 +304,7 @@ static ssize_t npcm_fiu_direct_read(struct spi_mem_dirmap_desc *desc,
>  			*(buf_rx + i) = ioread8(src + i);
>  	} else {
>  		if (desc->info.op_tmpl.addr.buswidth != fiu->drd_op.addr.buswidth ||
> -		    desc->info.op_tmpl.dummy.nbytes != fiu->drd_op.dummy.nbytes ||
> +		    desc->info.op_tmpl.dummy.ncycles != fiu->drd_op.dummy.ncycles ||
>  		    desc->info.op_tmpl.cmd.opcode != fiu->drd_op.cmd.opcode ||
>  		    desc->info.op_tmpl.addr.nbytes != fiu->drd_op.addr.nbytes)
>  			npcm_fiu_set_drd(fiu, &desc->info.op_tmpl);
> @@ -341,6 +346,10 @@ static int npcm_fiu_uma_read(struct spi_mem *mem,
>  	int ret;
>  	u32 val;
>  	u32 i;
> +	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
>  
>  	regmap_update_bits(fiu->regmap, NPCM_FIU_UMA_CTS,
>  			   NPCM_FIU_UMA_CTS_DEV_NUM,
> @@ -357,7 +366,7 @@ static int npcm_fiu_uma_read(struct spi_mem *mem,
>  			<< NPCM_FIU_UMA_CFG_DBPCK_SHIFT;
>  		uma_cfg |= ilog2(op->data.buswidth)
>  			<< NPCM_FIU_UMA_CFG_RDBPCK_SHIFT;
> -		uma_cfg |= op->dummy.nbytes << NPCM_FIU_UMA_CFG_DBSIZ_SHIFT;
> +		uma_cfg |= dummy_nbytes << NPCM_FIU_UMA_CFG_DBSIZ_SHIFT;
>  		uma_cfg |= op->addr.nbytes << NPCM_FIU_UMA_CFG_ADDSIZ_SHIFT;
>  		regmap_write(fiu->regmap, NPCM_FIU_UMA_ADDR, addr);
>  	} else {
> diff --git a/drivers/spi/spi-nxp-fspi.c b/drivers/spi/spi-nxp-fspi.c
> index 2b0301fc971c..ccec9b726283 100644
> --- a/drivers/spi/spi-nxp-fspi.c
> +++ b/drivers/spi/spi-nxp-fspi.c
> @@ -444,7 +444,7 @@ static bool nxp_fspi_supports_op(struct spi_mem *mem,
>  	if (op->addr.nbytes)
>  		ret |= nxp_fspi_check_buswidth(f, op->addr.buswidth);
>  
> -	if (op->dummy.nbytes)
> +	if (op->dummy.ncycles)
>  		ret |= nxp_fspi_check_buswidth(f, op->dummy.buswidth);
>  
>  	if (op->data.nbytes)
> @@ -468,8 +468,7 @@ static bool nxp_fspi_supports_op(struct spi_mem *mem,
>  		return false;
>  
>  	/* Max 64 dummy clock cycles supported */
> -	if (op->dummy.buswidth &&
> -	    (op->dummy.nbytes * 8 / op->dummy.buswidth > 64))
> +	if (op->dummy.ncycles > 64)
>  		return false;
>  
>  	/* Max data length, check controller limits and alignment */
> @@ -543,15 +542,14 @@ static void nxp_fspi_prepare_lut(struct nxp_fspi *f,
>  	}
>  
>  	/* dummy bytes, if needed */
> -	if (op->dummy.nbytes) {
> +	if (op->dummy.ncycles) {
>  		lutval[lutidx / 2] |= LUT_DEF(lutidx, LUT_DUMMY,
>  		/*
>  		 * Due to FlexSPI controller limitation number of PAD for dummy
>  		 * buswidth needs to be programmed as equal to data buswidth.
>  		 */
>  					      LUT_PAD(op->data.buswidth),
> -					      op->dummy.nbytes * 8 /
> -					      op->dummy.buswidth);
> +					      op->dummy.ncycles);
>  		lutidx++;
>  	}
>  
> diff --git a/drivers/spi/spi-rockchip-sfc.c b/drivers/spi/spi-rockchip-sfc.c
> index bd87d3c92dd3..82f9e61b9036 100644
> --- a/drivers/spi/spi-rockchip-sfc.c
> +++ b/drivers/spi/spi-rockchip-sfc.c
> @@ -282,16 +282,21 @@ static int rockchip_sfc_wait_rxfifo_ready(struct rockchip_sfc *sfc, u32 timeout_
>  
>  static void rockchip_sfc_adjust_op_work(struct spi_mem_op *op)
>  {
> -	if (unlikely(op->dummy.nbytes && !op->addr.nbytes)) {
> +	if (unlikely(op->dummy.ncycles && !op->addr.nbytes)) {
> +		u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +
> +		if (op->dummy.dtr)
> +			dummy_nbytes *= 2;
> +
>  		/*
>  		 * SFC not support output DUMMY cycles right after CMD cycles, so
>  		 * treat it as ADDR cycles.
>  		 */
> -		op->addr.nbytes = op->dummy.nbytes;
> +		op->addr.nbytes = dummy_nbytes;
>  		op->addr.buswidth = op->dummy.buswidth;
>  		op->addr.val = 0xFFFFFFFFF;
>  
> -		op->dummy.nbytes = 0;
> +		op->dummy.ncycles = 0;
>  	}
>  }
>  
> @@ -301,6 +306,10 @@ static int rockchip_sfc_xfer_setup(struct rockchip_sfc *sfc,
>  				   u32 len)
>  {
>  	u32 ctrl = 0, cmd = 0;
> +	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
>  
>  	/* set CMD */
>  	cmd = op->cmd.opcode;
> @@ -321,13 +330,13 @@ static int rockchip_sfc_xfer_setup(struct rockchip_sfc *sfc,
>  	}
>  
>  	/* set DUMMY */
> -	if (op->dummy.nbytes) {
> +	if (dummy_nbytes) {
>  		if (op->dummy.buswidth == 4)
> -			cmd |= op->dummy.nbytes * 2 << SFC_CMD_DUMMY_SHIFT;
> +			cmd |= dummy_nbytes * 2 << SFC_CMD_DUMMY_SHIFT;
>  		else if (op->dummy.buswidth == 2)
> -			cmd |= op->dummy.nbytes * 4 << SFC_CMD_DUMMY_SHIFT;
> +			cmd |= dummy_nbytes * 4 << SFC_CMD_DUMMY_SHIFT;
>  		else
> -			cmd |= op->dummy.nbytes * 8 << SFC_CMD_DUMMY_SHIFT;
> +			cmd |= dummy_nbytes * 8 << SFC_CMD_DUMMY_SHIFT;
>  	}
>  
>  	/* set DATA */
> @@ -348,9 +357,9 @@ static int rockchip_sfc_xfer_setup(struct rockchip_sfc *sfc,
>  	ctrl |= SFC_CTRL_PHASE_SEL_NEGETIVE;
>  	cmd |= mem->spi->chip_select << SFC_CMD_CS_SHIFT;
>  
> -	dev_dbg(sfc->dev, "sfc addr.nbytes=%x(x%d) dummy.nbytes=%x(x%d)\n",
> +	dev_dbg(sfc->dev, "sfc addr.nbytes=%x(x%d) dummy.ncycles=%x(x%d)\n",
>  		op->addr.nbytes, op->addr.buswidth,
> -		op->dummy.nbytes, op->dummy.buswidth);
> +		op->dummy.ncycles, op->dummy.buswidth);
>  	dev_dbg(sfc->dev, "sfc ctrl=%x cmd=%x addr=%llx len=%x\n",
>  		ctrl, cmd, op->addr.val, len);
>  
> diff --git a/drivers/spi/spi-rpc-if.c b/drivers/spi/spi-rpc-if.c
> index 24ec1c83f379..fb317a80bef8 100644
> --- a/drivers/spi/spi-rpc-if.c
> +++ b/drivers/spi/spi-rpc-if.c
> @@ -32,10 +32,9 @@ static void rpcif_spi_mem_prepare(struct spi_device *spi_dev,
>  		rpc_op.addr.val = spi_op->addr.val;
>  	}
>  
> -	if (spi_op->dummy.nbytes) {
> +	if (spi_op->dummy.ncycles) {
>  		rpc_op.dummy.buswidth = spi_op->dummy.buswidth;
> -		rpc_op.dummy.ncycles  = spi_op->dummy.nbytes * 8 /
> -					spi_op->dummy.buswidth;
> +		rpc_op.dummy.ncycles  = spi_op->dummy.ncycles;
>  	}
>  
>  	if (spi_op->data.nbytes || (offs && len)) {
> diff --git a/drivers/spi/spi-stm32-qspi.c b/drivers/spi/spi-stm32-qspi.c
> index f3fe92300639..9072345eddde 100644
> --- a/drivers/spi/spi-stm32-qspi.c
> +++ b/drivers/spi/spi-stm32-qspi.c
> @@ -388,9 +388,8 @@ static int stm32_qspi_send(struct spi_mem *mem, const struct spi_mem_op *op)
>  		ccr |= FIELD_PREP(CCR_ADSIZE_MASK, op->addr.nbytes - 1);
>  	}
>  
> -	if (op->dummy.nbytes)
> -		ccr |= FIELD_PREP(CCR_DCYC_MASK,
> -				  op->dummy.nbytes * 8 / op->dummy.buswidth);
> +	if (op->dummy.ncycles)
> +		ccr |= FIELD_PREP(CCR_DCYC_MASK, op->dummy.ncycles);
>  
>  	if (op->data.nbytes) {
>  		ccr |= FIELD_PREP(CCR_DMODE_MASK,
> diff --git a/drivers/spi/spi-ti-qspi.c b/drivers/spi/spi-ti-qspi.c
> index 60086869bcae..377bc119344f 100644
> --- a/drivers/spi/spi-ti-qspi.c
> +++ b/drivers/spi/spi-ti-qspi.c
> @@ -579,6 +579,10 @@ static int ti_qspi_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
>  {
>  	struct ti_qspi *qspi = spi_controller_get_devdata(mem->spi->master);
>  	size_t max_len;
> +	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
>  
>  	if (op->data.dir == SPI_MEM_DATA_IN) {
>  		if (op->addr.val < qspi->mmap_size) {
> @@ -595,7 +599,7 @@ static int ti_qspi_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
>  			 * Adjust size to comply with the QSPI max frame length.
>  			 */
>  			max_len = QSPI_FRAME;
> -			max_len -= 1 + op->addr.nbytes + op->dummy.nbytes;
> +			max_len -= 1 + op->addr.nbytes + dummy_nbytes;
>  			op->data.nbytes = min((size_t) op->data.nbytes,
>  					      max_len);
>  		}
> @@ -610,6 +614,10 @@ static int ti_qspi_exec_mem_op(struct spi_mem *mem,
>  	struct ti_qspi *qspi = spi_master_get_devdata(mem->spi->master);
>  	u32 from = 0;
>  	int ret = 0;
> +	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
>  
>  	/* Only optimize read path. */
>  	if (!op->data.nbytes || op->data.dir != SPI_MEM_DATA_IN ||
> @@ -628,7 +636,7 @@ static int ti_qspi_exec_mem_op(struct spi_mem *mem,
>  		ti_qspi_enable_memory_map(mem->spi);
>  	}
>  	ti_qspi_setup_mmap_read(mem->spi, op->cmd.opcode, op->data.buswidth,
> -				op->addr.nbytes, op->dummy.nbytes);
> +				op->addr.nbytes, dummy_nbytes);
>  
>  	if (qspi->rx_chan) {
>  		struct sg_table sgt;
> diff --git a/drivers/spi/spi-zynq-qspi.c b/drivers/spi/spi-zynq-qspi.c
> index 78f31b61a2aa..84b7db85548c 100644
> --- a/drivers/spi/spi-zynq-qspi.c
> +++ b/drivers/spi/spi-zynq-qspi.c
> @@ -527,7 +527,10 @@ static int zynq_qspi_exec_mem_op(struct spi_mem *mem,
>  {
>  	struct zynq_qspi *xqspi = spi_controller_get_devdata(mem->spi->master);
>  	int err = 0, i;
> -	u8 *tmpbuf;
> +	u8 *tmpbuf, dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
>  
>  	dev_dbg(xqspi->dev, "cmd:%#x mode:%d.%d.%d.%d\n",
>  		op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
> @@ -568,17 +571,17 @@ static int zynq_qspi_exec_mem_op(struct spi_mem *mem,
>  			err = -ETIMEDOUT;
>  	}
>  
> -	if (op->dummy.nbytes) {
> -		tmpbuf = kzalloc(op->dummy.nbytes, GFP_KERNEL);
> +	if (dummy_nbytes) {
> +		tmpbuf = kzalloc(dummy_nbytes, GFP_KERNEL);
>  		if (!tmpbuf)
>  			return -ENOMEM;
>  
> -		memset(tmpbuf, 0xff, op->dummy.nbytes);
> +		memset(tmpbuf, 0xff, dummy_nbytes);
>  		reinit_completion(&xqspi->data_completion);
>  		xqspi->txbuf = tmpbuf;
>  		xqspi->rxbuf = NULL;
> -		xqspi->tx_bytes = op->dummy.nbytes;
> -		xqspi->rx_bytes = op->dummy.nbytes;
> +		xqspi->tx_bytes = dummy_nbytes;
> +		xqspi->rx_bytes = dummy_nbytes;
>  		zynq_qspi_write_op(xqspi, ZYNQ_QSPI_FIFO_DEPTH, true);
>  		zynq_qspi_write(xqspi, ZYNQ_QSPI_IEN_OFFSET,
>  				ZYNQ_QSPI_IXR_RXTX_MASK);
> diff --git a/drivers/spi/spi-zynqmp-gqspi.c b/drivers/spi/spi-zynqmp-gqspi.c
> index c760aac070e5..b41abadef9a6 100644
> --- a/drivers/spi/spi-zynqmp-gqspi.c
> +++ b/drivers/spi/spi-zynqmp-gqspi.c
> @@ -948,6 +948,10 @@ static int zynqmp_qspi_exec_op(struct spi_mem *mem,
>  	u32 genfifoentry = 0;
>  	u16 opcode = op->cmd.opcode;
>  	u64 opaddr;
> +	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
>  
>  	dev_dbg(xqspi->dev, "cmd:%#x mode:%d.%d.%d.%d\n",
>  		op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
> @@ -1006,14 +1010,14 @@ static int zynqmp_qspi_exec_op(struct spi_mem *mem,
>  		}
>  	}
>  
> -	if (op->dummy.nbytes) {
> +	if (dummy_nbytes) {
>  		xqspi->txbuf = NULL;
>  		xqspi->rxbuf = NULL;
>  		/*
>  		 * xqspi->bytes_to_transfer here represents the dummy circles
>  		 * which need to be sent.
>  		 */
> -		xqspi->bytes_to_transfer = op->dummy.nbytes * 8 / op->dummy.buswidth;
> +		xqspi->bytes_to_transfer = dummy_nbytes;
>  		xqspi->bytes_to_receive = 0;
>  		/*
>  		 * Using op->data.buswidth instead of op->dummy.buswidth here because
> diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h
> index 2ba044d0d5e5..5fd45800af03 100644
> --- a/include/linux/spi/spi-mem.h
> +++ b/include/linux/spi/spi-mem.h
> @@ -29,9 +29,9 @@
>  
>  #define SPI_MEM_OP_NO_ADDR	{ }
>  
> -#define SPI_MEM_OP_DUMMY(__nbytes, __buswidth)			\
> +#define SPI_MEM_OP_DUMMY(__ncycles, __buswidth)		\
>  	{							\
> -		.nbytes = __nbytes,				\
> +		.ncycles = __ncycles,				\
>  		.buswidth = __buswidth,				\
>  	}
>  
> @@ -83,8 +83,8 @@ enum spi_mem_data_dir {
>   *	      Note that only @addr.nbytes are taken into account in this
>   *	      address value, so users should make sure the value fits in the
>   *	      assigned number of bytes.
> - * @dummy.nbytes: number of dummy bytes to send after an opcode or address. Can
> - *		  be zero if the operation does not require dummy bytes
> + * @dummy.ncycles: number of dummy cycles after an opcode or address. Can
> + *		   be zero if the operation does not require dummy cycles
>   * @dummy.buswidth: number of IO lanes used to transmit the dummy bytes
>   * @dummy.dtr: whether the dummy bytes should be sent in DTR mode or not
>   * @data.buswidth: number of IO lanes used to send/receive the data
> @@ -112,7 +112,7 @@ struct spi_mem_op {
>  	} addr;
>  
>  	struct {
> -		u8 nbytes;
> +		u8 ncycles;
>  		u8 buswidth;
>  		u8 dtr : 1;
>  	} dummy;

Tudor Ambarus Sept. 12, 2022, 10:58 a.m. UTC | #2

On 9/12/22 12:44, Patrice CHOTARD wrote:

Hi!

>> -             /* 2 bytes per clock cycle in DTR mode. */
>> -             op->dummy.nbytes *= 2;
>> -
> What is the benefit to remove dtr dummy.nbytes computation ? it leads to spray it in all drivers which support DTR.
> It was simpler to let the framework to deal with it, have i missed something ?

The majority of drivers from SPI need the number of cycles, not the number
of bytes. JESD216 refers to dummy ncycles as well, there's no such thing as
dummy nbytes. You'll notice that these drivers do the computation back to
ncycles in their driver, thus they undo what's prepared in SPI NOR. There
are just 4 drivers that use nbytes and rely on what's currently computed in
SPI NOR. Since these 4 drivers don't use the standard parameter and require
nbytes instead, they can do the conversion to nbytes in their driver.

Mark Brown Sept. 12, 2022, 11:52 a.m. UTC | #3

On Sun, Sep 11, 2022 at 08:45:53PM +0300, Sergiu Moga wrote:
> In order to properly represent the hardware functionality
> in the core, avoid reconverting the number of dummy cycles
> to the number of bytes and only work with the former.
> Instead, let the drivers that do need this conversion do
> it themselves.

Acked-by: Mark Brown <[e-mail]>

If this gets applied it might be good to have a tag in case we
need it for any SPI updates.

Serge Semin Sept. 25, 2022, 10:03 p.m. UTC | #4

Hello Sergiu

On Sun, Sep 11, 2022 at 08:45:53PM +0300, Sergiu Moga wrote:
> In order to properly represent the hardware functionality
> in the core, avoid reconverting the number of dummy cycles
> to the number of bytes and only work with the former.
> Instead, let the drivers that do need this conversion do
> it themselves.
> 
> Signed-off-by: Sergiu Moga <[e-mail]>
> ---
>  drivers/mtd/spi-nor/core.c        | 22 ++++----------

[...]

>  drivers/spi/spi-dw-core.c         | 10 +++++--

[...]

>  drivers/spi/spi-mem.c             | 27 +++++++++++------

[...]

>  drivers/spi/spi-mtk-nor.c         | 48 +++++++++++++++++--------------

[...]

>  drivers/spi/spi-zynq-qspi.c       | 15 ++++++----
>  drivers/spi/spi-zynqmp-gqspi.c    |  8 ++++--
>  include/linux/spi/spi-mem.h       | 10 +++----
>  25 files changed, 234 insertions(+), 147 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
> index f2c64006f8d7..cc8ca824f912 100644
> --- a/drivers/mtd/spi-nor/core.c
> +++ b/drivers/mtd/spi-nor/core.c
> @@ -88,7 +88,7 @@ void spi_nor_spimem_setup_op(const struct spi_nor *nor,
>  	if (op->addr.nbytes)
>  		op->addr.buswidth = spi_nor_get_protocol_addr_nbits(proto);
>  



> -	if (op->dummy.nbytes)
> +	if (op->dummy.ncycles)
>  		op->dummy.buswidth = spi_nor_get_protocol_addr_nbits(proto);
>  
>  	if (op->data.nbytes)
> @@ -106,9 +106,6 @@ void spi_nor_spimem_setup_op(const struct spi_nor *nor,
>  		op->dummy.dtr = true;
>  		op->data.dtr = true;
>  
> -		/* 2 bytes per clock cycle in DTR mode. */
> -		op->dummy.nbytes *= 2;
> -
>  		ext = spi_nor_get_cmd_ext(nor, op);
>  		op->cmd.opcode = (op->cmd.opcode << 8) | ext;
>  		op->cmd.nbytes = 2;
> @@ -207,10 +204,7 @@ static ssize_t spi_nor_spimem_read_data(struct spi_nor *nor, loff_t from,
>  
>  	spi_nor_spimem_setup_op(nor, &op, nor->read_proto);
>  
> -	/* convert the dummy cycles to the number of bytes */
> -	op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
> -	if (spi_nor_protocol_is_dtr(nor->read_proto))
> -		op.dummy.nbytes *= 2;
> +	op.dummy.ncycles = nor->read_dummy;

So according to this modification and what is done in the rest of the
patch, the dummy part of the SPI-mem operations now contains the number
of cycles only. Am I right to think that it means a number of dummy
clock oscillations? (Judging from what I've seen in the HW-manuals of
the SPI NOR memory devices most likely I am...) If so the "ncycles" field
is now free from the "data" semantic. Then what is the meaning of the
"buswidth and "dtr" fields in the spi_mem_op.dummy field?

>  
>  	usebouncebuf = spi_nor_spimem_bounce(nor, &op);
>  
> @@ -455,7 +449,7 @@ int spi_nor_read_sr(struct spi_nor *nor, u8 *sr)
>  
>  		if (nor->reg_proto == SNOR_PROTO_8_8_8_DTR) {
>  			op.addr.nbytes = nor->params->rdsr_addr_nbytes;
> -			op.dummy.nbytes = nor->params->rdsr_dummy;
> +			op.dummy.ncycles = nor->params->rdsr_dummy;
>  			/*
>  			 * We don't want to read only one byte in DTR mode. So,
>  			 * read 2 and then discard the second byte.
> @@ -1913,10 +1907,7 @@ static int spi_nor_spimem_check_readop(struct spi_nor *nor,
>  
>  	spi_nor_spimem_setup_op(nor, &op, read->proto);
>  
> -	/* convert the dummy cycles to the number of bytes */
> -	op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
> -	if (spi_nor_protocol_is_dtr(nor->read_proto))
> -		op.dummy.nbytes *= 2;
> +	op.dummy.ncycles = nor->read_dummy;
>  
>  	return spi_nor_spimem_check_op(nor, &op);
>  }
> @@ -3034,10 +3025,7 @@ static int spi_nor_create_read_dirmap(struct spi_nor *nor)
>  
>  	spi_nor_spimem_setup_op(nor, op, nor->read_proto);
>  
> -	/* convert the dummy cycles to the number of bytes */
> -	op->dummy.nbytes = (nor->read_dummy * op->dummy.buswidth) / 8;
> -	if (spi_nor_protocol_is_dtr(nor->read_proto))
> -		op->dummy.nbytes *= 2;
> +	op->dummy.ncycles = nor->read_dummy;
>  
>  	/*
>  	 * Since spi_nor_spimem_setup_op() only sets buswidth when the number

[...]

> diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c
> index f87d97ccd2d6..0ba5c7d0e66e 100644
> --- a/drivers/spi/spi-dw-core.c
> +++ b/drivers/spi/spi-dw-core.c
> @@ -498,13 +498,17 @@ static bool dw_spi_supports_mem_op(struct spi_mem *mem,
>  static int dw_spi_init_mem_buf(struct dw_spi *dws, const struct spi_mem_op *op)
>  {
>  	unsigned int i, j, len;
> -	u8 *out;
> +	u8 *out, dummy_nbytes;
>  
>  	/*
>  	 * Calculate the total length of the EEPROM command transfer and
>  	 * either use the pre-allocated buffer or create a temporary one.
>  	 */
> -	len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;

> +	dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;

1. What about using the BITS_PER_BYTE macro (linux/bits.h) here? Since
you are adding a similar modification to so many drivers what about using
that macro there too?

2. buswidth is supposed to be always 1 in this driver (see the
dw_spi_supports_mem_op() method). So it can be dropped from the
statement above.

3. Since the ncycles now contains a number of clock cycles there is no
point in taking the SPI bus-width into account at all. What is
meaningful is how many oscillations are supposed to be placed on the
CLK line before the data is available. So the op->dummy.ncycles /
BITS_PER_BYTE statement would be more appropriate here in any case.

> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;

DTR is unsupported by the controller. See, no spi_controller_mem_caps
initialized. So this part is redundant. The same is most likely
applicable for some of the DTR-related updates in this patch too
since the spi_controller_mem_caps structure is initialized in a few
drivers only.

> +
> +	len = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes;
>  	if (op->data.dir == SPI_MEM_DATA_OUT)
>  		len += op->data.nbytes;
>  
> @@ -525,7 +529,7 @@ static int dw_spi_init_mem_buf(struct dw_spi *dws, const struct spi_mem_op *op)
>  		out[i] = DW_SPI_GET_BYTE(op->cmd.opcode, op->cmd.nbytes - i - 1);
>  	for (j = 0; j < op->addr.nbytes; ++i, ++j)
>  		out[i] = DW_SPI_GET_BYTE(op->addr.val, op->addr.nbytes - j - 1);
> -	for (j = 0; j < op->dummy.nbytes; ++i, ++j)
> +	for (j = 0; j < dummy_nbytes; ++i, ++j)
>  		out[i] = 0x0;
>  
>  	if (op->data.dir == SPI_MEM_DATA_OUT)

[...]

> diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
> index 0c79193d9697..7b204963bb62 100644
> --- a/drivers/spi/spi-mem.c
> +++ b/drivers/spi/spi-mem.c
> @@ -149,7 +149,7 @@ static bool spi_mem_check_buswidth(struct spi_mem *mem,
>  	    spi_check_buswidth_req(mem, op->addr.buswidth, true))
>  		return false;
>  
> -	if (op->dummy.nbytes &&
> +	if (op->dummy.ncycles &&
>  	    spi_check_buswidth_req(mem, op->dummy.buswidth, true))
>  		return false;
>  
> @@ -202,7 +202,7 @@ static int spi_mem_check_op(const struct spi_mem_op *op)
>  		return -EINVAL;
>  
>  	if ((op->addr.nbytes && !op->addr.buswidth) ||
> -	    (op->dummy.nbytes && !op->dummy.buswidth) ||
> +	    (op->dummy.ncycles && !op->dummy.buswidth) ||
>  	    (op->data.nbytes && !op->data.buswidth))
>  		return -EINVAL;
>  
> @@ -315,7 +315,7 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)

>  	struct spi_controller *ctlr = mem->spi->controller;
>  	struct spi_transfer xfers[4] = { };
>  	struct spi_message msg;
> -	u8 *tmpbuf;
> +	u8 *tmpbuf, dummy_nbytes;
>  	int ret;

Reverse xmas tree order?

>  
>  	ret = spi_mem_check_op(op);
> @@ -343,7 +343,11 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
>  			return ret;
>  	}
>  

> -	tmpbufsize = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
> +	dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;

So ncycles now indeed is a number of CLK line oscillations. This most
likely will break the SPI Nand driver then, which still passes the
number of bytes to the SPI_MEM_OP_DUMMY() macro.

> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;

Generic SPI-mem ops don't take the DTR mode into account. So I don't
see this necessary.

> +
> +	tmpbufsize = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes;
>  
>  	/*
>  	 * Allocate a buffer to transmit the CMD, ADDR cycles with kmalloc() so
> @@ -379,15 +383,15 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
>  		totalxferlen += op->addr.nbytes;
>  	}
>  
> -	if (op->dummy.nbytes) {
> -		memset(tmpbuf + op->addr.nbytes + 1, 0xff, op->dummy.nbytes);
> +	if (dummy_nbytes) {
> +		memset(tmpbuf + op->addr.nbytes + 1, 0xff, dummy_nbytes);
>  		xfers[xferpos].tx_buf = tmpbuf + op->addr.nbytes + 1;
> -		xfers[xferpos].len = op->dummy.nbytes;
> +		xfers[xferpos].len = dummy_nbytes;
>  		xfers[xferpos].tx_nbits = op->dummy.buswidth;
>  		xfers[xferpos].dummy_data = 1;
>  		spi_message_add_tail(&xfers[xferpos], &msg);
>  		xferpos++;
> -		totalxferlen += op->dummy.nbytes;
> +		totalxferlen += dummy_nbytes;
>  	}
>  
>  	if (op->data.nbytes) {
> @@ -456,12 +460,17 @@ int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
>  {

>  	struct spi_controller *ctlr = mem->spi->controller;
>  	size_t len;
> +	u8 dummy_nbytes;

reverse xmas tree?

>  
>  	if (ctlr->mem_ops && ctlr->mem_ops->adjust_op_size)
>  		return ctlr->mem_ops->adjust_op_size(mem, op);
>  
> +	dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;
> +
>  	if (!ctlr->mem_ops || !ctlr->mem_ops->exec_op) {
> -		len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
> +		len = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes;
>  
>  		if (len > spi_max_transfer_size(mem->spi))
>  			return -EINVAL;

[...]
  
> diff --git a/drivers/spi/spi-mtk-nor.c b/drivers/spi/spi-mtk-nor.c
> index d167699a1a96..f6870c6e911a 100644
> --- a/drivers/spi/spi-mtk-nor.c
> +++ b/drivers/spi/spi-mtk-nor.c
> @@ -171,23 +171,18 @@ static bool need_bounce(struct mtk_nor *sp, const struct spi_mem_op *op)
>  
>  static bool mtk_nor_match_read(const struct spi_mem_op *op)
>  {
> -	int dummy = 0;
> -
> -	if (op->dummy.nbytes)
> -		dummy = op->dummy.nbytes * BITS_PER_BYTE / op->dummy.buswidth;
> -
>  	if ((op->data.buswidth == 2) || (op->data.buswidth == 4)) {
>  		if (op->addr.buswidth == 1)
> -			return dummy == 8;
> +			return op->dummy.ncycles == 8;
>  		else if (op->addr.buswidth == 2)
> -			return dummy == 4;
> +			return op->dummy.ncycles == 4;
>  		else if (op->addr.buswidth == 4)
> -			return dummy == 6;
> +			return op->dummy.ncycles == 6;
>  	} else if ((op->addr.buswidth == 1) && (op->data.buswidth == 1)) {
>  		if (op->cmd.opcode == 0x03)
> -			return dummy == 0;
> +			return op->dummy.ncycles == 0;
>  		else if (op->cmd.opcode == 0x0b)
> -			return dummy == 8;
> +			return op->dummy.ncycles == 8;
>  	}
>  	return false;
>  }
> @@ -195,6 +190,10 @@ static bool mtk_nor_match_read(const struct spi_mem_op *op)
>  static bool mtk_nor_match_prg(const struct spi_mem_op *op)
>  {
>  	int tx_len, rx_len, prg_len, prg_left;

> +	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +

IMO it's better to move the initialization statement to a separate
line here.

> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;

Does the MTK SPI driver support DTR? AFAICS it doesn't.

>  
>  	// prg mode is spi-only.
>  	if ((op->cmd.buswidth > 1) || (op->addr.buswidth > 1) ||
> @@ -205,7 +204,7 @@ static bool mtk_nor_match_prg(const struct spi_mem_op *op)
>  
>  	if (op->data.dir == SPI_MEM_DATA_OUT) {
>  		// count dummy bytes only if we need to write data after it
> -		tx_len += op->dummy.nbytes;
> +		tx_len += dummy_nbytes;
>  
>  		// leave at least one byte for data
>  		if (tx_len > MTK_NOR_REG_PRGDATA_MAX)
> @@ -221,7 +220,7 @@ static bool mtk_nor_match_prg(const struct spi_mem_op *op)
>  			return false;
>  
>  		rx_len = op->data.nbytes;
> -		prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - op->dummy.nbytes;
> +		prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - dummy_nbytes;
>  		if (prg_left > MTK_NOR_REG_SHIFT_MAX + 1)
>  			prg_left = MTK_NOR_REG_SHIFT_MAX + 1;
>  		if (rx_len > prg_left) {
> @@ -230,11 +229,11 @@ static bool mtk_nor_match_prg(const struct spi_mem_op *op)
>  			rx_len = prg_left;
>  		}
>  
> -		prg_len = tx_len + op->dummy.nbytes + rx_len;
> +		prg_len = tx_len + dummy_nbytes + rx_len;
>  		if (prg_len > MTK_NOR_PRG_CNT_MAX / 8)
>  			return false;
>  	} else {
> -		prg_len = tx_len + op->dummy.nbytes;
> +		prg_len = tx_len + dummy_nbytes;
>  		if (prg_len > MTK_NOR_PRG_CNT_MAX / 8)
>  			return false;
>  	}
> @@ -244,15 +243,19 @@ static bool mtk_nor_match_prg(const struct spi_mem_op *op)
>  static void mtk_nor_adj_prg_size(struct spi_mem_op *op)
>  {
>  	int tx_len, tx_left, prg_left;

> +	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;

ditto

>  
>  	tx_len = op->cmd.nbytes + op->addr.nbytes;
>  	if (op->data.dir == SPI_MEM_DATA_OUT) {
> -		tx_len += op->dummy.nbytes;
> +		tx_len += dummy_nbytes;
>  		tx_left = MTK_NOR_REG_PRGDATA_MAX + 1 - tx_len;
>  		if (op->data.nbytes > tx_left)
>  			op->data.nbytes = tx_left;
>  	} else if (op->data.dir == SPI_MEM_DATA_IN) {
> -		prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - op->dummy.nbytes;
> +		prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - dummy_nbytes;
>  		if (prg_left > MTK_NOR_REG_SHIFT_MAX + 1)
>  			prg_left = MTK_NOR_REG_SHIFT_MAX + 1;
>  		if (op->data.nbytes > prg_left)
> @@ -312,7 +315,7 @@ static bool mtk_nor_supports_op(struct spi_mem *mem,
>  			break;
>  		case SPI_MEM_DATA_OUT:
>  			if ((op->addr.buswidth == 1) &&
> -			    (op->dummy.nbytes == 0) &&
> +			    (op->dummy.ncycles == 0) &&
>  			    (op->data.buswidth == 1))
>  				return true;
>  			break;
> @@ -515,17 +518,20 @@ static int mtk_nor_spi_mem_prg(struct mtk_nor *sp, const struct spi_mem_op *op)
>  	int tx_len, prg_len;
>  	int i, ret;
>  	void __iomem *reg;

> -	u8 bufbyte;
> +	u8 bufbyte, dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;

ditto

>  
>  	tx_len = op->cmd.nbytes + op->addr.nbytes;
>  
>  	// count dummy bytes only if we need to write data after it
>  	if (op->data.dir == SPI_MEM_DATA_OUT)
> -		tx_len += op->dummy.nbytes + op->data.nbytes;
> +		tx_len += dummy_nbytes + op->data.nbytes;
>  	else if (op->data.dir == SPI_MEM_DATA_IN)
>  		rx_len = op->data.nbytes;
>  
> -	prg_len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes +
> +	prg_len = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes +
>  		  op->data.nbytes;
>  
>  	// an invalid op may reach here if the caller calls exec_op without
> @@ -550,7 +556,7 @@ static int mtk_nor_spi_mem_prg(struct mtk_nor *sp, const struct spi_mem_op *op)
>  	}
>  
>  	if (op->data.dir == SPI_MEM_DATA_OUT) {
> -		for (i = 0; i < op->dummy.nbytes; i++, reg_offset--) {
> +		for (i = 0; i < dummy_nbytes; i++, reg_offset--) {
>  			reg = sp->base + MTK_NOR_REG_PRGDATA(reg_offset);
>  			writeb(0, reg);
>  		}

[...]
  
> diff --git a/drivers/spi/spi-zynq-qspi.c b/drivers/spi/spi-zynq-qspi.c
> index 78f31b61a2aa..84b7db85548c 100644
> --- a/drivers/spi/spi-zynq-qspi.c
> +++ b/drivers/spi/spi-zynq-qspi.c
> @@ -527,7 +527,10 @@ static int zynq_qspi_exec_mem_op(struct spi_mem *mem,
>  {
>  	struct zynq_qspi *xqspi = spi_controller_get_devdata(mem->spi->master);
>  	int err = 0, i;
> -	u8 *tmpbuf;
> +	u8 *tmpbuf, dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;

Separate line?

> +
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;

Is DTR supported by the driver?

>  
>  	dev_dbg(xqspi->dev, "cmd:%#x mode:%d.%d.%d.%d\n",
>  		op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
> @@ -568,17 +571,17 @@ static int zynq_qspi_exec_mem_op(struct spi_mem *mem,
>  			err = -ETIMEDOUT;
>  	}
>  
> -	if (op->dummy.nbytes) {
> -		tmpbuf = kzalloc(op->dummy.nbytes, GFP_KERNEL);
> +	if (dummy_nbytes) {
> +		tmpbuf = kzalloc(dummy_nbytes, GFP_KERNEL);
>  		if (!tmpbuf)
>  			return -ENOMEM;
>  
> -		memset(tmpbuf, 0xff, op->dummy.nbytes);
> +		memset(tmpbuf, 0xff, dummy_nbytes);
>  		reinit_completion(&xqspi->data_completion);
>  		xqspi->txbuf = tmpbuf;
>  		xqspi->rxbuf = NULL;
> -		xqspi->tx_bytes = op->dummy.nbytes;
> -		xqspi->rx_bytes = op->dummy.nbytes;
> +		xqspi->tx_bytes = dummy_nbytes;
> +		xqspi->rx_bytes = dummy_nbytes;
>  		zynq_qspi_write_op(xqspi, ZYNQ_QSPI_FIFO_DEPTH, true);
>  		zynq_qspi_write(xqspi, ZYNQ_QSPI_IEN_OFFSET,
>  				ZYNQ_QSPI_IXR_RXTX_MASK);
> diff --git a/drivers/spi/spi-zynqmp-gqspi.c b/drivers/spi/spi-zynqmp-gqspi.c
> index c760aac070e5..b41abadef9a6 100644
> --- a/drivers/spi/spi-zynqmp-gqspi.c
> +++ b/drivers/spi/spi-zynqmp-gqspi.c
> @@ -948,6 +948,10 @@ static int zynqmp_qspi_exec_op(struct spi_mem *mem,
>  	u32 genfifoentry = 0;
>  	u16 opcode = op->cmd.opcode;
>  	u64 opaddr;

> +	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> +
> +	if (op->dummy.dtr)
> +		dummy_nbytes *= 2;

ditto

>  
>  	dev_dbg(xqspi->dev, "cmd:%#x mode:%d.%d.%d.%d\n",
>  		op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
> @@ -1006,14 +1010,14 @@ static int zynqmp_qspi_exec_op(struct spi_mem *mem,
>  		}
>  	}
>  
> -	if (op->dummy.nbytes) {
> +	if (dummy_nbytes) {
>  		xqspi->txbuf = NULL;
>  		xqspi->rxbuf = NULL;
>  		/*
>  		 * xqspi->bytes_to_transfer here represents the dummy circles
>  		 * which need to be sent.
>  		 */
> -		xqspi->bytes_to_transfer = op->dummy.nbytes * 8 / op->dummy.buswidth;
> +		xqspi->bytes_to_transfer = dummy_nbytes;
>  		xqspi->bytes_to_receive = 0;
>  		/*
>  		 * Using op->data.buswidth instead of op->dummy.buswidth here because
> diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h
> index 2ba044d0d5e5..5fd45800af03 100644
> --- a/include/linux/spi/spi-mem.h
> +++ b/include/linux/spi/spi-mem.h
> @@ -29,9 +29,9 @@
>  
>  #define SPI_MEM_OP_NO_ADDR	{ }
>  

> -#define SPI_MEM_OP_DUMMY(__nbytes, __buswidth)			\
> +#define SPI_MEM_OP_DUMMY(__ncycles, __buswidth)		\
>  	{							\

> -		.nbytes = __nbytes,				\
> +		.ncycles = __ncycles,				\
>  		.buswidth = __buswidth,				\

Please make sure this update and the drivers/spi/spi-mem.c driver
alterations are coherent with the SPI Nand driver. See the macro usages:
include/linux/mtd/spinand.h: SPINAND_PAGE_READ_FROM_*().

-Sergey

>  	}
>  
> @@ -83,8 +83,8 @@ enum spi_mem_data_dir {
>   *	      Note that only @addr.nbytes are taken into account in this
>   *	      address value, so users should make sure the value fits in the
>   *	      assigned number of bytes.
> - * @dummy.nbytes: number of dummy bytes to send after an opcode or address. Can
> - *		  be zero if the operation does not require dummy bytes
> + * @dummy.ncycles: number of dummy cycles after an opcode or address. Can
> + *		   be zero if the operation does not require dummy cycles
>   * @dummy.buswidth: number of IO lanes used to transmit the dummy bytes
>   * @dummy.dtr: whether the dummy bytes should be sent in DTR mode or not
>   * @data.buswidth: number of IO lanes used to send/receive the data
> @@ -112,7 +112,7 @@ struct spi_mem_op {
>  	} addr;
>  
>  	struct {
> -		u8 nbytes;
> +		u8 ncycles;
>  		u8 buswidth;
>  		u8 dtr : 1;
>  	} dummy;
> -- 
> 2.34.1
>

Sergiu Moga Sept. 26, 2022, 9:05 a.m. UTC | #5

On 26.09.2022 01:03, Serge Semin wrote:
> Hello Sergiu
> 


Hello Serge,


> On Sun, Sep 11, 2022 at 08:45:53PM +0300, Sergiu Moga wrote:
>> In order to properly represent the hardware functionality
>> in the core, avoid reconverting the number of dummy cycles
>> to the number of bytes and only work with the former.
>> Instead, let the drivers that do need this conversion do
>> it themselves.
>>
>> Signed-off-by: Sergiu Moga <[e-mail]>
>> ---
>>   drivers/mtd/spi-nor/core.c        | 22 ++++----------
> 
> [...]
> 
>>   drivers/spi/spi-dw-core.c         | 10 +++++--
> 
> [...]
> 
>>   drivers/spi/spi-mem.c             | 27 +++++++++++------
> 
> [...]
> 
>>   drivers/spi/spi-mtk-nor.c         | 48 +++++++++++++++++--------------
> 
> [...]
> 
>>   drivers/spi/spi-zynq-qspi.c       | 15 ++++++----
>>   drivers/spi/spi-zynqmp-gqspi.c    |  8 ++++--
>>   include/linux/spi/spi-mem.h       | 10 +++----
>>   25 files changed, 234 insertions(+), 147 deletions(-)
>>
>> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
>> index f2c64006f8d7..cc8ca824f912 100644
>> --- a/drivers/mtd/spi-nor/core.c
>> +++ b/drivers/mtd/spi-nor/core.c
>> @@ -88,7 +88,7 @@ void spi_nor_spimem_setup_op(const struct spi_nor *nor,
>>        if (op->addr.nbytes)
>>                op->addr.buswidth = spi_nor_get_protocol_addr_nbits(proto);
>>
> 
> 
> 
>> -     if (op->dummy.nbytes)
>> +     if (op->dummy.ncycles)
>>                op->dummy.buswidth = spi_nor_get_protocol_addr_nbits(proto);
>>
>>        if (op->data.nbytes)
>> @@ -106,9 +106,6 @@ void spi_nor_spimem_setup_op(const struct spi_nor *nor,
>>                op->dummy.dtr = true;
>>                op->data.dtr = true;
>>
>> -             /* 2 bytes per clock cycle in DTR mode. */
>> -             op->dummy.nbytes *= 2;
>> -
>>                ext = spi_nor_get_cmd_ext(nor, op);
>>                op->cmd.opcode = (op->cmd.opcode << 8) | ext;
>>                op->cmd.nbytes = 2;
>> @@ -207,10 +204,7 @@ static ssize_t spi_nor_spimem_read_data(struct spi_nor *nor, loff_t from,
>>
>>        spi_nor_spimem_setup_op(nor, &op, nor->read_proto);
>>
>> -     /* convert the dummy cycles to the number of bytes */
>> -     op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
>> -     if (spi_nor_protocol_is_dtr(nor->read_proto))
>> -             op.dummy.nbytes *= 2;
>> +     op.dummy.ncycles = nor->read_dummy;
> 
> So according to this modification and what is done in the rest of the
> patch, the dummy part of the SPI-mem operations now contains the number
> of cycles only. Am I right to think that it means a number of dummy
> clock oscillations? (Judging from what I've seen in the HW-manuals of
> the SPI NOR memory devices most likely I am...)



Yes, you are correct.


> If so the "ncycles" field
> is now free from the "data" semantic. Then what is the meaning of the
> "buswidth and "dtr" fields in the spi_mem_op.dummy field?
> 


It is still meaningful as it is used for the conversion by some drivers 
to nbytes and I do not see how it goes out of the specification in any 
way. So, at least for now, I do not see any reason to remove these fields.


>>
>>        usebouncebuf = spi_nor_spimem_bounce(nor, &op);
>>
>> @@ -455,7 +449,7 @@ int spi_nor_read_sr(struct spi_nor *nor, u8 *sr)
>>
>>                if (nor->reg_proto == SNOR_PROTO_8_8_8_DTR) {
>>                        op.addr.nbytes = nor->params->rdsr_addr_nbytes;
>> -                     op.dummy.nbytes = nor->params->rdsr_dummy;
>> +                     op.dummy.ncycles = nor->params->rdsr_dummy;
>>                        /*
>>                         * We don't want to read only one byte in DTR mode. So,
>>                         * read 2 and then discard the second byte.
>> @@ -1913,10 +1907,7 @@ static int spi_nor_spimem_check_readop(struct spi_nor *nor,
>>
>>        spi_nor_spimem_setup_op(nor, &op, read->proto);
>>
>> -     /* convert the dummy cycles to the number of bytes */
>> -     op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
>> -     if (spi_nor_protocol_is_dtr(nor->read_proto))
>> -             op.dummy.nbytes *= 2;
>> +     op.dummy.ncycles = nor->read_dummy;
>>
>>        return spi_nor_spimem_check_op(nor, &op);
>>   }
>> @@ -3034,10 +3025,7 @@ static int spi_nor_create_read_dirmap(struct spi_nor *nor)
>>
>>        spi_nor_spimem_setup_op(nor, op, nor->read_proto);
>>
>> -     /* convert the dummy cycles to the number of bytes */
>> -     op->dummy.nbytes = (nor->read_dummy * op->dummy.buswidth) / 8;
>> -     if (spi_nor_protocol_is_dtr(nor->read_proto))
>> -             op->dummy.nbytes *= 2;
>> +     op->dummy.ncycles = nor->read_dummy;
>>
>>        /*
>>         * Since spi_nor_spimem_setup_op() only sets buswidth when the number
> 
> [...]
> 
>> diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c
>> index f87d97ccd2d6..0ba5c7d0e66e 100644
>> --- a/drivers/spi/spi-dw-core.c
>> +++ b/drivers/spi/spi-dw-core.c
>> @@ -498,13 +498,17 @@ static bool dw_spi_supports_mem_op(struct spi_mem *mem,
>>   static int dw_spi_init_mem_buf(struct dw_spi *dws, const struct spi_mem_op *op)
>>   {
>>        unsigned int i, j, len;
>> -     u8 *out;
>> +     u8 *out, dummy_nbytes;
>>
>>        /*
>>         * Calculate the total length of the EEPROM command transfer and
>>         * either use the pre-allocated buffer or create a temporary one.
>>         */
>> -     len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
> 
>> +     dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> 
> 1. What about using the BITS_PER_BYTE macro (linux/bits.h) here? Since
> you are adding a similar modification to so many drivers what about using
> that macro there too?
> 


AFAICT BIT_PER_BYTE is meant to transparently indicate how many bits per 
byte an arch has. Although, there is no place in the kernel from what I 
can see that has BITS_PER_BYTE with a value other than 8, you cannot 
deny that there exist architectures whose number of bits per byte may be 
different from 8.

Meanwhile, the JESD216E specification tells us in the Terms and 
definitions chapter that
"DWORD: Four consecutive 8-bit bytes used as the basic 32-bit building 
block for headers and parameter tables." So it explicitly says that a 
byte has 8 bits regardless of the arch.

Therefore, I do not agree with replacing 8 with the BITS_PER_BYTE macro 
as, IMO, it does not represent the same thing as the number of bits per 
byte that the terms and definitions of the JESD216E specification refer to.


> 2. buswidth is supposed to be always 1 in this driver (see the
> dw_spi_supports_mem_op() method). So it can be dropped from the
> statement above.
> 
> 3. Since the ncycles now contains a number of clock cycles there is no
> point in taking the SPI bus-width into account at all. What is
> meaningful is how many oscillations are supposed to be placed on the
> CLK line before the data is available. So the op->dummy.ncycles /
> BITS_PER_BYTE statement would be more appropriate here in any case.
> 


I can agee with this in the case of this driver, sure.


>> +     if (op->dummy.dtr)
>> +             dummy_nbytes *= 2;
> 
> DTR is unsupported by the controller. See, no spi_controller_mem_caps
> initialized. So this part is redundant. The same is most likely
> applicable for some of the DTR-related updates in this patch too
> since the spi_controller_mem_caps structure is initialized in a few
> drivers only.
> 


Agreed. Initially, wherever I was not sure, I just placed this if 
condition to avoid breaking anything in case the driver does support 
DTR. The same goes for your other related observations to other driver 
modifications, with which I agree :).


>> +
>> +     len = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes;
>>        if (op->data.dir == SPI_MEM_DATA_OUT)
>>                len += op->data.nbytes;
>>
>> @@ -525,7 +529,7 @@ static int dw_spi_init_mem_buf(struct dw_spi *dws, const struct spi_mem_op *op)
>>                out[i] = DW_SPI_GET_BYTE(op->cmd.opcode, op->cmd.nbytes - i - 1);
>>        for (j = 0; j < op->addr.nbytes; ++i, ++j)
>>                out[i] = DW_SPI_GET_BYTE(op->addr.val, op->addr.nbytes - j - 1);
>> -     for (j = 0; j < op->dummy.nbytes; ++i, ++j)
>> +     for (j = 0; j < dummy_nbytes; ++i, ++j)
>>                out[i] = 0x0;
>>
>>        if (op->data.dir == SPI_MEM_DATA_OUT)
> 
> [...]
> 
>> diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
>> index 0c79193d9697..7b204963bb62 100644
>> --- a/drivers/spi/spi-mem.c
>> +++ b/drivers/spi/spi-mem.c
>> @@ -149,7 +149,7 @@ static bool spi_mem_check_buswidth(struct spi_mem *mem,
>>            spi_check_buswidth_req(mem, op->addr.buswidth, true))
>>                return false;
>>
>> -     if (op->dummy.nbytes &&
>> +     if (op->dummy.ncycles &&
>>            spi_check_buswidth_req(mem, op->dummy.buswidth, true))
>>                return false;
>>
>> @@ -202,7 +202,7 @@ static int spi_mem_check_op(const struct spi_mem_op *op)
>>                return -EINVAL;
>>
>>        if ((op->addr.nbytes && !op->addr.buswidth) ||
>> -         (op->dummy.nbytes && !op->dummy.buswidth) ||
>> +         (op->dummy.ncycles && !op->dummy.buswidth) ||
>>            (op->data.nbytes && !op->data.buswidth))
>>                return -EINVAL;
>>
>> @@ -315,7 +315,7 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
> 
>>        struct spi_controller *ctlr = mem->spi->controller;
>>        struct spi_transfer xfers[4] = { };
>>        struct spi_message msg;
>> -     u8 *tmpbuf;
>> +     u8 *tmpbuf, dummy_nbytes;
>>        int ret;
> 
> Reverse xmas tree order?
> 
>>
>>        ret = spi_mem_check_op(op);
>> @@ -343,7 +343,11 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
>>                        return ret;
>>        }
>>
> 
>> -     tmpbufsize = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
>> +     dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> 
> So ncycles now indeed is a number of CLK line oscillations. This most
> likely will break the SPI Nand driver then, which still passes the
> number of bytes to the SPI_MEM_OP_DUMMY() macro.
> 
>> +     if (op->dummy.dtr)
>> +             dummy_nbytes *= 2;
> 
> Generic SPI-mem ops don't take the DTR mode into account. So I don't
> see this necessary.
> 


You may be right, but this part of the code does take into consideration 
the number of dummy.nbytes to calculate the xfer length. Therefore, 
shouldn't this code block also know if the number of dummy nbytes is 
actually double the amount that it calculated through the conversion 
formula?


>> +
>> +     tmpbufsize = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes;
>>
>>        /*
>>         * Allocate a buffer to transmit the CMD, ADDR cycles with kmalloc() so
>> @@ -379,15 +383,15 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
>>                totalxferlen += op->addr.nbytes;
>>        }
>>
>> -     if (op->dummy.nbytes) {
>> -             memset(tmpbuf + op->addr.nbytes + 1, 0xff, op->dummy.nbytes);
>> +     if (dummy_nbytes) {
>> +             memset(tmpbuf + op->addr.nbytes + 1, 0xff, dummy_nbytes);
>>                xfers[xferpos].tx_buf = tmpbuf + op->addr.nbytes + 1;
>> -             xfers[xferpos].len = op->dummy.nbytes;
>> +             xfers[xferpos].len = dummy_nbytes;
>>                xfers[xferpos].tx_nbits = op->dummy.buswidth;
>>                xfers[xferpos].dummy_data = 1;
>>                spi_message_add_tail(&xfers[xferpos], &msg);
>>                xferpos++;
>> -             totalxferlen += op->dummy.nbytes;
>> +             totalxferlen += dummy_nbytes;
>>        }
>>
>>        if (op->data.nbytes) {
>> @@ -456,12 +460,17 @@ int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
>>   {
> 
>>        struct spi_controller *ctlr = mem->spi->controller;
>>        size_t len;
>> +     u8 dummy_nbytes;
> 
> reverse xmas tree?
> 
>>
>>        if (ctlr->mem_ops && ctlr->mem_ops->adjust_op_size)
>>                return ctlr->mem_ops->adjust_op_size(mem, op);
>>
>> +     dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
>> +     if (op->dummy.dtr)
>> +             dummy_nbytes *= 2;
>> +
>>        if (!ctlr->mem_ops || !ctlr->mem_ops->exec_op) {
>> -             len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
>> +             len = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes;
>>
>>                if (len > spi_max_transfer_size(mem->spi))
>>                        return -EINVAL;
> 
> [...]
> 
>> diff --git a/drivers/spi/spi-mtk-nor.c b/drivers/spi/spi-mtk-nor.c
>> index d167699a1a96..f6870c6e911a 100644
>> --- a/drivers/spi/spi-mtk-nor.c
>> +++ b/drivers/spi/spi-mtk-nor.c
>> @@ -171,23 +171,18 @@ static bool need_bounce(struct mtk_nor *sp, const struct spi_mem_op *op)
>>
>>   static bool mtk_nor_match_read(const struct spi_mem_op *op)
>>   {
>> -     int dummy = 0;
>> -
>> -     if (op->dummy.nbytes)
>> -             dummy = op->dummy.nbytes * BITS_PER_BYTE / op->dummy.buswidth;
>> -
>>        if ((op->data.buswidth == 2) || (op->data.buswidth == 4)) {
>>                if (op->addr.buswidth == 1)
>> -                     return dummy == 8;
>> +                     return op->dummy.ncycles == 8;
>>                else if (op->addr.buswidth == 2)
>> -                     return dummy == 4;
>> +                     return op->dummy.ncycles == 4;
>>                else if (op->addr.buswidth == 4)
>> -                     return dummy == 6;
>> +                     return op->dummy.ncycles == 6;
>>        } else if ((op->addr.buswidth == 1) && (op->data.buswidth == 1)) {
>>                if (op->cmd.opcode == 0x03)
>> -                     return dummy == 0;
>> +                     return op->dummy.ncycles == 0;
>>                else if (op->cmd.opcode == 0x0b)
>> -                     return dummy == 8;
>> +                     return op->dummy.ncycles == 8;
>>        }
>>        return false;
>>   }
>> @@ -195,6 +190,10 @@ static bool mtk_nor_match_read(const struct spi_mem_op *op)
>>   static bool mtk_nor_match_prg(const struct spi_mem_op *op)
>>   {
>>        int tx_len, rx_len, prg_len, prg_left;
> 
>> +     u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
>> +
> 
> IMO it's better to move the initialization statement to a separate
> line here.
> 
>> +     if (op->dummy.dtr)
>> +             dummy_nbytes *= 2;
> 
> Does the MTK SPI driver support DTR? AFAICS it doesn't.
> 
>>
>>        // prg mode is spi-only.
>>        if ((op->cmd.buswidth > 1) || (op->addr.buswidth > 1) ||
>> @@ -205,7 +204,7 @@ static bool mtk_nor_match_prg(const struct spi_mem_op *op)
>>
>>        if (op->data.dir == SPI_MEM_DATA_OUT) {
>>                // count dummy bytes only if we need to write data after it
>> -             tx_len += op->dummy.nbytes;
>> +             tx_len += dummy_nbytes;
>>
>>                // leave at least one byte for data
>>                if (tx_len > MTK_NOR_REG_PRGDATA_MAX)
>> @@ -221,7 +220,7 @@ static bool mtk_nor_match_prg(const struct spi_mem_op *op)
>>                        return false;
>>
>>                rx_len = op->data.nbytes;
>> -             prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - op->dummy.nbytes;
>> +             prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - dummy_nbytes;
>>                if (prg_left > MTK_NOR_REG_SHIFT_MAX + 1)
>>                        prg_left = MTK_NOR_REG_SHIFT_MAX + 1;
>>                if (rx_len > prg_left) {
>> @@ -230,11 +229,11 @@ static bool mtk_nor_match_prg(const struct spi_mem_op *op)
>>                        rx_len = prg_left;
>>                }
>>
>> -             prg_len = tx_len + op->dummy.nbytes + rx_len;
>> +             prg_len = tx_len + dummy_nbytes + rx_len;
>>                if (prg_len > MTK_NOR_PRG_CNT_MAX / 8)
>>                        return false;
>>        } else {
>> -             prg_len = tx_len + op->dummy.nbytes;
>> +             prg_len = tx_len + dummy_nbytes;
>>                if (prg_len > MTK_NOR_PRG_CNT_MAX / 8)
>>                        return false;
>>        }
>> @@ -244,15 +243,19 @@ static bool mtk_nor_match_prg(const struct spi_mem_op *op)
>>   static void mtk_nor_adj_prg_size(struct spi_mem_op *op)
>>   {
>>        int tx_len, tx_left, prg_left;
> 
>> +     u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
>> +
>> +     if (op->dummy.dtr)
>> +             dummy_nbytes *= 2;
> 
> ditto
> 
>>
>>        tx_len = op->cmd.nbytes + op->addr.nbytes;
>>        if (op->data.dir == SPI_MEM_DATA_OUT) {
>> -             tx_len += op->dummy.nbytes;
>> +             tx_len += dummy_nbytes;
>>                tx_left = MTK_NOR_REG_PRGDATA_MAX + 1 - tx_len;
>>                if (op->data.nbytes > tx_left)
>>                        op->data.nbytes = tx_left;
>>        } else if (op->data.dir == SPI_MEM_DATA_IN) {
>> -             prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - op->dummy.nbytes;
>> +             prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - dummy_nbytes;
>>                if (prg_left > MTK_NOR_REG_SHIFT_MAX + 1)
>>                        prg_left = MTK_NOR_REG_SHIFT_MAX + 1;
>>                if (op->data.nbytes > prg_left)
>> @@ -312,7 +315,7 @@ static bool mtk_nor_supports_op(struct spi_mem *mem,
>>                        break;
>>                case SPI_MEM_DATA_OUT:
>>                        if ((op->addr.buswidth == 1) &&
>> -                         (op->dummy.nbytes == 0) &&
>> +                         (op->dummy.ncycles == 0) &&
>>                            (op->data.buswidth == 1))
>>                                return true;
>>                        break;
>> @@ -515,17 +518,20 @@ static int mtk_nor_spi_mem_prg(struct mtk_nor *sp, const struct spi_mem_op *op)
>>        int tx_len, prg_len;
>>        int i, ret;
>>        void __iomem *reg;
> 
>> -     u8 bufbyte;
>> +     u8 bufbyte, dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
>> +
>> +     if (op->dummy.dtr)
>> +             dummy_nbytes *= 2;
> 
> ditto
> 
>>
>>        tx_len = op->cmd.nbytes + op->addr.nbytes;
>>
>>        // count dummy bytes only if we need to write data after it
>>        if (op->data.dir == SPI_MEM_DATA_OUT)
>> -             tx_len += op->dummy.nbytes + op->data.nbytes;
>> +             tx_len += dummy_nbytes + op->data.nbytes;
>>        else if (op->data.dir == SPI_MEM_DATA_IN)
>>                rx_len = op->data.nbytes;
>>
>> -     prg_len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes +
>> +     prg_len = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes +
>>                  op->data.nbytes;
>>
>>        // an invalid op may reach here if the caller calls exec_op without
>> @@ -550,7 +556,7 @@ static int mtk_nor_spi_mem_prg(struct mtk_nor *sp, const struct spi_mem_op *op)
>>        }
>>
>>        if (op->data.dir == SPI_MEM_DATA_OUT) {
>> -             for (i = 0; i < op->dummy.nbytes; i++, reg_offset--) {
>> +             for (i = 0; i < dummy_nbytes; i++, reg_offset--) {
>>                        reg = sp->base + MTK_NOR_REG_PRGDATA(reg_offset);
>>                        writeb(0, reg);
>>                }
> 
> [...]
> 
>> diff --git a/drivers/spi/spi-zynq-qspi.c b/drivers/spi/spi-zynq-qspi.c
>> index 78f31b61a2aa..84b7db85548c 100644
>> --- a/drivers/spi/spi-zynq-qspi.c
>> +++ b/drivers/spi/spi-zynq-qspi.c
>> @@ -527,7 +527,10 @@ static int zynq_qspi_exec_mem_op(struct spi_mem *mem,
>>   {
>>        struct zynq_qspi *xqspi = spi_controller_get_devdata(mem->spi->master);
>>        int err = 0, i;
>> -     u8 *tmpbuf;
>> +     u8 *tmpbuf, dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> 
> Separate line?
> 
>> +
>> +     if (op->dummy.dtr)
>> +             dummy_nbytes *= 2;
> 
> Is DTR supported by the driver?
> 


Not from what I can see, but I was not 100% sure so I placed this if 
statement here just in case.



>>
>>        dev_dbg(xqspi->dev, "cmd:%#x mode:%d.%d.%d.%d\n",
>>                op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
>> @@ -568,17 +571,17 @@ static int zynq_qspi_exec_mem_op(struct spi_mem *mem,
>>                        err = -ETIMEDOUT;
>>        }
>>
>> -     if (op->dummy.nbytes) {
>> -             tmpbuf = kzalloc(op->dummy.nbytes, GFP_KERNEL);
>> +     if (dummy_nbytes) {
>> +             tmpbuf = kzalloc(dummy_nbytes, GFP_KERNEL);
>>                if (!tmpbuf)
>>                        return -ENOMEM;
>>
>> -             memset(tmpbuf, 0xff, op->dummy.nbytes);
>> +             memset(tmpbuf, 0xff, dummy_nbytes);
>>                reinit_completion(&xqspi->data_completion);
>>                xqspi->txbuf = tmpbuf;
>>                xqspi->rxbuf = NULL;
>> -             xqspi->tx_bytes = op->dummy.nbytes;
>> -             xqspi->rx_bytes = op->dummy.nbytes;
>> +             xqspi->tx_bytes = dummy_nbytes;
>> +             xqspi->rx_bytes = dummy_nbytes;
>>                zynq_qspi_write_op(xqspi, ZYNQ_QSPI_FIFO_DEPTH, true);
>>                zynq_qspi_write(xqspi, ZYNQ_QSPI_IEN_OFFSET,
>>                                ZYNQ_QSPI_IXR_RXTX_MASK);
>> diff --git a/drivers/spi/spi-zynqmp-gqspi.c b/drivers/spi/spi-zynqmp-gqspi.c
>> index c760aac070e5..b41abadef9a6 100644
>> --- a/drivers/spi/spi-zynqmp-gqspi.c
>> +++ b/drivers/spi/spi-zynqmp-gqspi.c
>> @@ -948,6 +948,10 @@ static int zynqmp_qspi_exec_op(struct spi_mem *mem,
>>        u32 genfifoentry = 0;
>>        u16 opcode = op->cmd.opcode;
>>        u64 opaddr;
> 
>> +     u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
>> +
>> +     if (op->dummy.dtr)
>> +             dummy_nbytes *= 2;
> 
> ditto
> 
>>
>>        dev_dbg(xqspi->dev, "cmd:%#x mode:%d.%d.%d.%d\n",
>>                op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
>> @@ -1006,14 +1010,14 @@ static int zynqmp_qspi_exec_op(struct spi_mem *mem,
>>                }
>>        }
>>
>> -     if (op->dummy.nbytes) {
>> +     if (dummy_nbytes) {
>>                xqspi->txbuf = NULL;
>>                xqspi->rxbuf = NULL;
>>                /*
>>                 * xqspi->bytes_to_transfer here represents the dummy circles
>>                 * which need to be sent.
>>                 */
>> -             xqspi->bytes_to_transfer = op->dummy.nbytes * 8 / op->dummy.buswidth;
>> +             xqspi->bytes_to_transfer = dummy_nbytes;
>>                xqspi->bytes_to_receive = 0;
>>                /*
>>                 * Using op->data.buswidth instead of op->dummy.buswidth here because
>> diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h
>> index 2ba044d0d5e5..5fd45800af03 100644
>> --- a/include/linux/spi/spi-mem.h
>> +++ b/include/linux/spi/spi-mem.h
>> @@ -29,9 +29,9 @@
>>
>>   #define SPI_MEM_OP_NO_ADDR   { }
>>
> 
>> -#define SPI_MEM_OP_DUMMY(__nbytes, __buswidth)                       \
>> +#define SPI_MEM_OP_DUMMY(__ncycles, __buswidth)              \
>>        {                                                       \
> 
>> -             .nbytes = __nbytes,                             \
>> +             .ncycles = __ncycles,                           \
>>                .buswidth = __buswidth,                         \
> 
> Please make sure this update and the drivers/spi/spi-mem.c driver
> alterations are coherent with the SPI Nand driver. See the macro usages:
> include/linux/mtd/spinand.h: SPINAND_PAGE_READ_FROM_*().
> 
> -Sergey
>


Yes, indeed, I should have paid more attention here. As I have 
previously said,  I simply replaced dummy.nbytes with the code sequences 
you now see. I should have checked for SPI_MEM_OP_DUMMY usages as well 
since I changed its definition. Thank you! :)


>>        }
>>
>> @@ -83,8 +83,8 @@ enum spi_mem_data_dir {
>>    *         Note that only @addr.nbytes are taken into account in this
>>    *         address value, so users should make sure the value fits in the
>>    *         assigned number of bytes.
>> - * @dummy.nbytes: number of dummy bytes to send after an opcode or address. Can
>> - *             be zero if the operation does not require dummy bytes
>> + * @dummy.ncycles: number of dummy cycles after an opcode or address. Can
>> + *              be zero if the operation does not require dummy cycles
>>    * @dummy.buswidth: number of IO lanes used to transmit the dummy bytes
>>    * @dummy.dtr: whether the dummy bytes should be sent in DTR mode or not
>>    * @data.buswidth: number of IO lanes used to send/receive the data
>> @@ -112,7 +112,7 @@ struct spi_mem_op {
>>        } addr;
>>
>>        struct {
>> -             u8 nbytes;
>> +             u8 ncycles;
>>                u8 buswidth;
>>                u8 dtr : 1;
>>        } dummy;
>> --
>> 2.34.1
>>


Regards,
	Sergiu

Serge Semin Sept. 26, 2022, 5:24 p.m. UTC | #6

@Mark, @Tudor, @Pratyush, @Michael could you please join the
discussion regarding the dummy.buswidth and dummy.dtr fields in the
spi_mem_op structure?

On Mon, Sep 26, 2022 at 09:05:49AM +0000, [e-mail] wrote:
> On 26.09.2022 01:03, Serge Semin wrote:
> > Hello Sergiu
> > 

Sergiu, you didn't address all my comments. Please be more attentive.

> 
> 
> Hello Serge,
> 
> 
> > On Sun, Sep 11, 2022 at 08:45:53PM +0300, Sergiu Moga wrote:
> >> In order to properly represent the hardware functionality
> >> in the core, avoid reconverting the number of dummy cycles
> >> to the number of bytes and only work with the former.
> >> Instead, let the drivers that do need this conversion do
> >> it themselves.
> >>
> >> Signed-off-by: Sergiu Moga <[e-mail]>
> >> ---
> >>   drivers/mtd/spi-nor/core.c        | 22 ++++----------
> > 
> > [...]
> > 
> >>   drivers/spi/spi-dw-core.c         | 10 +++++--
> > 
> > [...]
> > 
> >>   drivers/spi/spi-mem.c             | 27 +++++++++++------
> > 
> > [...]
> > 
> >>   drivers/spi/spi-mtk-nor.c         | 48 +++++++++++++++++--------------
> > 
> > [...]
> > 
> >>   drivers/spi/spi-zynq-qspi.c       | 15 ++++++----
> >>   drivers/spi/spi-zynqmp-gqspi.c    |  8 ++++--
> >>   include/linux/spi/spi-mem.h       | 10 +++----
> >>   25 files changed, 234 insertions(+), 147 deletions(-)
> >>
> >> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
> >> index f2c64006f8d7..cc8ca824f912 100644
> >> --- a/drivers/mtd/spi-nor/core.c
> >> +++ b/drivers/mtd/spi-nor/core.c
> >> @@ -88,7 +88,7 @@ void spi_nor_spimem_setup_op(const struct spi_nor *nor,
> >>        if (op->addr.nbytes)
> >>                op->addr.buswidth = spi_nor_get_protocol_addr_nbits(proto);
> >>
> > 
> > 
> > 
> >> -     if (op->dummy.nbytes)
> >> +     if (op->dummy.ncycles)
> >>                op->dummy.buswidth = spi_nor_get_protocol_addr_nbits(proto);
> >>
> >>        if (op->data.nbytes)
> >> @@ -106,9 +106,6 @@ void spi_nor_spimem_setup_op(const struct spi_nor *nor,
> >>                op->dummy.dtr = true;
> >>                op->data.dtr = true;
> >>
> >> -             /* 2 bytes per clock cycle in DTR mode. */
> >> -             op->dummy.nbytes *= 2;
> >> -
> >>                ext = spi_nor_get_cmd_ext(nor, op);
> >>                op->cmd.opcode = (op->cmd.opcode << 8) | ext;
> >>                op->cmd.nbytes = 2;
> >> @@ -207,10 +204,7 @@ static ssize_t spi_nor_spimem_read_data(struct spi_nor *nor, loff_t from,
> >>
> >>        spi_nor_spimem_setup_op(nor, &op, nor->read_proto);
> >>
> >> -     /* convert the dummy cycles to the number of bytes */
> >> -     op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
> >> -     if (spi_nor_protocol_is_dtr(nor->read_proto))
> >> -             op.dummy.nbytes *= 2;
> >> +     op.dummy.ncycles = nor->read_dummy;
> > 
> > So according to this modification and what is done in the rest of the
> > patch, the dummy part of the SPI-mem operations now contains the number
> > of cycles only. Am I right to think that it means a number of dummy
> > clock oscillations? (Judging from what I've seen in the HW-manuals of
> > the SPI NOR memory devices most likely I am...)
> 
> 
> 
> Yes, you are correct.
> 
> 
> > If so the "ncycles" field
> > is now free from the "data" semantic. Then what is the meaning of the
> > "buswidth and "dtr" fields in the spi_mem_op.dummy field?
> > 
> 
> 

> It is still meaningful as it is used for the conversion by some drivers 
> to nbytes and I do not see how it goes out of the specification in any 
> way. So, at least for now, I do not see any reason to remove these fields.

I do see the way these fields are used in the SPI-mem drivers. I was
wondering what do these bits mean in the framework of the SPI-mem
core? AFAICS from the specification the dummy cycles are irrelevant to
the data bus state. It says "the master tri-states the bus during
'dummy' cycles." If so I don't see a reason to have the DTR and
buswidth fields in the spi_mem_op structure anymore. The number of
cycles could be calculated right on the initialization stage based on
the SPI NOR/NAND requirements.

@Mark, @Tudor, @Pratyush, what do you think?

> 
> 
> >>
> >>        usebouncebuf = spi_nor_spimem_bounce(nor, &op);
> >>
> >> @@ -455,7 +449,7 @@ int spi_nor_read_sr(struct spi_nor *nor, u8 *sr)
> >>
> >>                if (nor->reg_proto == SNOR_PROTO_8_8_8_DTR) {
> >>                        op.addr.nbytes = nor->params->rdsr_addr_nbytes;
> >> -                     op.dummy.nbytes = nor->params->rdsr_dummy;
> >> +                     op.dummy.ncycles = nor->params->rdsr_dummy;
> >>                        /*
> >>                         * We don't want to read only one byte in DTR mode. So,
> >>                         * read 2 and then discard the second byte.
> >> @@ -1913,10 +1907,7 @@ static int spi_nor_spimem_check_readop(struct spi_nor *nor,
> >>
> >>        spi_nor_spimem_setup_op(nor, &op, read->proto);
> >>
> >> -     /* convert the dummy cycles to the number of bytes */
> >> -     op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
> >> -     if (spi_nor_protocol_is_dtr(nor->read_proto))
> >> -             op.dummy.nbytes *= 2;
> >> +     op.dummy.ncycles = nor->read_dummy;
> >>
> >>        return spi_nor_spimem_check_op(nor, &op);
> >>   }
> >> @@ -3034,10 +3025,7 @@ static int spi_nor_create_read_dirmap(struct spi_nor *nor)
> >>
> >>        spi_nor_spimem_setup_op(nor, op, nor->read_proto);
> >>
> >> -     /* convert the dummy cycles to the number of bytes */
> >> -     op->dummy.nbytes = (nor->read_dummy * op->dummy.buswidth) / 8;
> >> -     if (spi_nor_protocol_is_dtr(nor->read_proto))
> >> -             op->dummy.nbytes *= 2;
> >> +     op->dummy.ncycles = nor->read_dummy;
> >>
> >>        /*
> >>         * Since spi_nor_spimem_setup_op() only sets buswidth when the number
> > 
> > [...]
> > 
> >> diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c
> >> index f87d97ccd2d6..0ba5c7d0e66e 100644
> >> --- a/drivers/spi/spi-dw-core.c
> >> +++ b/drivers/spi/spi-dw-core.c
> >> @@ -498,13 +498,17 @@ static bool dw_spi_supports_mem_op(struct spi_mem *mem,
> >>   static int dw_spi_init_mem_buf(struct dw_spi *dws, const struct spi_mem_op *op)
> >>   {
> >>        unsigned int i, j, len;
> >> -     u8 *out;
> >> +     u8 *out, dummy_nbytes;
> >>
> >>        /*
> >>         * Calculate the total length of the EEPROM command transfer and
> >>         * either use the pre-allocated buffer or create a temporary one.
> >>         */
> >> -     len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
> > 
> >> +     dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> > 
> > 1. What about using the BITS_PER_BYTE macro (linux/bits.h) here? Since
> > you are adding a similar modification to so many drivers what about using
> > that macro there too?
> > 
> 
> 

> AFAICT BIT_PER_BYTE is meant to transparently indicate how many bits per 
> byte an arch has. Although, there is no place in the kernel from what I 
> can see that has BITS_PER_BYTE with a value other than 8, you cannot 
> deny that there exist architectures whose number of bits per byte may be 
> different from 8.

Judging by the way the macro is declared it isn't platform specific.
So no, the kernel always expects the byte having eight bits.

> 
> Meanwhile, the JESD216E specification tells us in the Terms and 
> definitions chapter that
> "DWORD: Four consecutive 8-bit bytes used as the basic 32-bit building 
> block for headers and parameter tables." So it explicitly says that a 
> byte has 8 bits regardless of the arch.

Right. That's what the BITS_PER_BYTE macro is for.

> 
> Therefore, I do not agree with replacing 8 with the BITS_PER_BYTE macro 
> as, IMO, it does not represent the same thing as the number of bits per 
> byte that the terms and definitions of the JESD216E specification refer to.

It represents exactly the same in include/linux/bits.h .

Ideally it would be good to use it in all your updates since you touch
the corresponding parts anyway. But at the very least I would insist on
using the macro in the drivers which already have it utilized like
spi-dw-*, spi-mtk-snfi, spi-mtk-nor. 

> 
> 
> > 2. buswidth is supposed to be always 1 in this driver (see the
> > dw_spi_supports_mem_op() method). So it can be dropped from the
> > statement above.
> > 
> > 3. Since the ncycles now contains a number of clock cycles there is no
> > point in taking the SPI bus-width into account at all. What is
> > meaningful is how many oscillations are supposed to be placed on the
> > CLK line before the data is available. So the op->dummy.ncycles /
> > BITS_PER_BYTE statement would be more appropriate here in any case.
> > 
> 
> 

> I can agee with this in the case of this driver, sure.

Ok. thanks.

> 
> 
> >> +     if (op->dummy.dtr)
> >> +             dummy_nbytes *= 2;
> > 
> > DTR is unsupported by the controller. See, no spi_controller_mem_caps
> > initialized. So this part is redundant. The same is most likely
> > applicable for some of the DTR-related updates in this patch too
> > since the spi_controller_mem_caps structure is initialized in a few
> > drivers only.
> > 
> 
> 

> Agreed. Initially, wherever I was not sure, I just placed this if 
> condition to avoid breaking anything in case the driver does support 
> DTR. The same goes for your other related observations to other driver 
> modifications, with which I agree :).

AFAICS the only drivers which support the DTR-capable transfers are
the ones having the spi_controller_mem_caps structure defined with dtr
set to true or the ones with custom SPI-mem ops. It means that the
DTR-transfers are supported by the spi-mtk-snfi.c, spi-mxic.c,
spi-cadence-quadspi.c and spi-intel.c drivers only. The rest of the
SPI-controller drivers will fail to execute the SPI-mem ops with dtr
flag set due to the spi_mem_default_supports_op() method semantics.

> 
> 
> >> +
> >> +     len = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes;
> >>        if (op->data.dir == SPI_MEM_DATA_OUT)
> >>                len += op->data.nbytes;
> >>
> >> @@ -525,7 +529,7 @@ static int dw_spi_init_mem_buf(struct dw_spi *dws, const struct spi_mem_op *op)
> >>                out[i] = DW_SPI_GET_BYTE(op->cmd.opcode, op->cmd.nbytes - i - 1);
> >>        for (j = 0; j < op->addr.nbytes; ++i, ++j)
> >>                out[i] = DW_SPI_GET_BYTE(op->addr.val, op->addr.nbytes - j - 1);
> >> -     for (j = 0; j < op->dummy.nbytes; ++i, ++j)
> >> +     for (j = 0; j < dummy_nbytes; ++i, ++j)
> >>                out[i] = 0x0;
> >>
> >>        if (op->data.dir == SPI_MEM_DATA_OUT)
> > 
> > [...]
> > 
> >> diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
> >> index 0c79193d9697..7b204963bb62 100644
> >> --- a/drivers/spi/spi-mem.c
> >> +++ b/drivers/spi/spi-mem.c
> >> @@ -149,7 +149,7 @@ static bool spi_mem_check_buswidth(struct spi_mem *mem,
> >>            spi_check_buswidth_req(mem, op->addr.buswidth, true))
> >>                return false;
> >>
> >> -     if (op->dummy.nbytes &&
> >> +     if (op->dummy.ncycles &&
> >>            spi_check_buswidth_req(mem, op->dummy.buswidth, true))
> >>                return false;
> >>
> >> @@ -202,7 +202,7 @@ static int spi_mem_check_op(const struct spi_mem_op *op)
> >>                return -EINVAL;
> >>
> >>        if ((op->addr.nbytes && !op->addr.buswidth) ||
> >> -         (op->dummy.nbytes && !op->dummy.buswidth) ||
> >> +         (op->dummy.ncycles && !op->dummy.buswidth) ||
> >>            (op->data.nbytes && !op->data.buswidth))
> >>                return -EINVAL;
> >>
> >> @@ -315,7 +315,7 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
> > 
> >>        struct spi_controller *ctlr = mem->spi->controller;
> >>        struct spi_transfer xfers[4] = { };
> >>        struct spi_message msg;
> >> -     u8 *tmpbuf;
> >> +     u8 *tmpbuf, dummy_nbytes;
> >>        int ret;
> > 

> > Reverse xmas tree order?

Please take this note into account. Preserving the locally defined
coding-style convention is a very useful practice. It retains the code
uniformity, which improves readability and maintainability for just no
price.

> > 
> >>
> >>        ret = spi_mem_check_op(op);
> >> @@ -343,7 +343,11 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
> >>                        return ret;
> >>        }
> >>
> > 
> >> -     tmpbufsize = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
> >> +     dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> > 
> > So ncycles now indeed is a number of CLK line oscillations. This most
> > likely will break the SPI Nand driver then, which still passes the
> > number of bytes to the SPI_MEM_OP_DUMMY() macro.
> > 
> >> +     if (op->dummy.dtr)
> >> +             dummy_nbytes *= 2;
> > 
> > Generic SPI-mem ops don't take the DTR mode into account. So I don't
> > see this necessary.
> > 
> 
> 

> You may be right, but this part of the code does take into consideration 
> the number of dummy.nbytes to calculate the xfer length. Therefore, 
> shouldn't this code block also know if the number of dummy nbytes is 
> actually double the amount that it calculated through the conversion 
> formula?

Ok. This part turns to be debatable indeed. On the first glance the
SPI-mem core doesn't anyhow handles the DTR-flag value. On the other
hand SPI-controllers may have the dtr-capability flag set thus, for
instance implicitly supporting the DTR transfers. Finally currently
all the DTR-aware drivers are known to have the custom SPI-mem ops
defined. So some aspects say for dropping the dummy.dtr field usage
from here, some say against it. I'll leave it for you and @Mark,
@Tudor, @Pratyush to decide.

> 
> 
> >> +
> >> +     tmpbufsize = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes;
> >>
> >>        /*
> >>         * Allocate a buffer to transmit the CMD, ADDR cycles with kmalloc() so
> >> @@ -379,15 +383,15 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
> >>                totalxferlen += op->addr.nbytes;
> >>        }
> >>
> >> -     if (op->dummy.nbytes) {
> >> -             memset(tmpbuf + op->addr.nbytes + 1, 0xff, op->dummy.nbytes);
> >> +     if (dummy_nbytes) {
> >> +             memset(tmpbuf + op->addr.nbytes + 1, 0xff, dummy_nbytes);
> >>                xfers[xferpos].tx_buf = tmpbuf + op->addr.nbytes + 1;
> >> -             xfers[xferpos].len = op->dummy.nbytes;
> >> +             xfers[xferpos].len = dummy_nbytes;
> >>                xfers[xferpos].tx_nbits = op->dummy.buswidth;
> >>                xfers[xferpos].dummy_data = 1;
> >>                spi_message_add_tail(&xfers[xferpos], &msg);
> >>                xferpos++;
> >> -             totalxferlen += op->dummy.nbytes;
> >> +             totalxferlen += dummy_nbytes;
> >>        }
> >>
> >>        if (op->data.nbytes) {
> >> @@ -456,12 +460,17 @@ int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
> >>   {
> > 
> >>        struct spi_controller *ctlr = mem->spi->controller;
> >>        size_t len;
> >> +     u8 dummy_nbytes;
> > 

> > reverse xmas tree?

Please retain the local coding style convention.

> > 
> >>
> >>        if (ctlr->mem_ops && ctlr->mem_ops->adjust_op_size)
> >>                return ctlr->mem_ops->adjust_op_size(mem, op);
> >>
> >> +     dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> >> +     if (op->dummy.dtr)
> >> +             dummy_nbytes *= 2;
> >> +
> >>        if (!ctlr->mem_ops || !ctlr->mem_ops->exec_op) {
> >> -             len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
> >> +             len = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes;
> >>
> >>                if (len > spi_max_transfer_size(mem->spi))
> >>                        return -EINVAL;
> > 
> > [...]
> > 
> >> diff --git a/drivers/spi/spi-mtk-nor.c b/drivers/spi/spi-mtk-nor.c
> >> index d167699a1a96..f6870c6e911a 100644
> >> --- a/drivers/spi/spi-mtk-nor.c
> >> +++ b/drivers/spi/spi-mtk-nor.c
> >> @@ -171,23 +171,18 @@ static bool need_bounce(struct mtk_nor *sp, const struct spi_mem_op *op)
> >>
> >>   static bool mtk_nor_match_read(const struct spi_mem_op *op)
> >>   {
> >> -     int dummy = 0;
> >> -
> >> -     if (op->dummy.nbytes)
> >> -             dummy = op->dummy.nbytes * BITS_PER_BYTE / op->dummy.buswidth;
> >> -
> >>        if ((op->data.buswidth == 2) || (op->data.buswidth == 4)) {
> >>                if (op->addr.buswidth == 1)
> >> -                     return dummy == 8;
> >> +                     return op->dummy.ncycles == 8;
> >>                else if (op->addr.buswidth == 2)
> >> -                     return dummy == 4;
> >> +                     return op->dummy.ncycles == 4;
> >>                else if (op->addr.buswidth == 4)
> >> -                     return dummy == 6;
> >> +                     return op->dummy.ncycles == 6;
> >>        } else if ((op->addr.buswidth == 1) && (op->data.buswidth == 1)) {
> >>                if (op->cmd.opcode == 0x03)
> >> -                     return dummy == 0;
> >> +                     return op->dummy.ncycles == 0;
> >>                else if (op->cmd.opcode == 0x0b)
> >> -                     return dummy == 8;
> >> +                     return op->dummy.ncycles == 8;
> >>        }
> >>        return false;
> >>   }
> >> @@ -195,6 +190,10 @@ static bool mtk_nor_match_read(const struct spi_mem_op *op)
> >>   static bool mtk_nor_match_prg(const struct spi_mem_op *op)
> >>   {
> >>        int tx_len, rx_len, prg_len, prg_left;
> > 


> >> +     u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> >> +
> > 
> > IMO it's better to move the initialization statement to a separate
> > line here.

Again. The initialization statement is too long. It makes the code
harder to read. Just split the declaration and initialization up.

> > 
> >> +     if (op->dummy.dtr)
> >> +             dummy_nbytes *= 2;
> > 

> > Does the MTK SPI driver support DTR? AFAICS it doesn't.

I'll give an answer. It doesn't. The spi_mem_exec_op() will return the
-ENOTSUPP error if an SPI-mem op with any dtr flag set is requested.

> > 
> >>
> >>        // prg mode is spi-only.
> >>        if ((op->cmd.buswidth > 1) || (op->addr.buswidth > 1) ||
> >> @@ -205,7 +204,7 @@ static bool mtk_nor_match_prg(const struct spi_mem_op *op)
> >>
> >>        if (op->data.dir == SPI_MEM_DATA_OUT) {
> >>                // count dummy bytes only if we need to write data after it
> >> -             tx_len += op->dummy.nbytes;
> >> +             tx_len += dummy_nbytes;
> >>
> >>                // leave at least one byte for data
> >>                if (tx_len > MTK_NOR_REG_PRGDATA_MAX)
> >> @@ -221,7 +220,7 @@ static bool mtk_nor_match_prg(const struct spi_mem_op *op)
> >>                        return false;
> >>
> >>                rx_len = op->data.nbytes;
> >> -             prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - op->dummy.nbytes;
> >> +             prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - dummy_nbytes;
> >>                if (prg_left > MTK_NOR_REG_SHIFT_MAX + 1)
> >>                        prg_left = MTK_NOR_REG_SHIFT_MAX + 1;
> >>                if (rx_len > prg_left) {
> >> @@ -230,11 +229,11 @@ static bool mtk_nor_match_prg(const struct spi_mem_op *op)
> >>                        rx_len = prg_left;
> >>                }
> >>
> >> -             prg_len = tx_len + op->dummy.nbytes + rx_len;
> >> +             prg_len = tx_len + dummy_nbytes + rx_len;
> >>                if (prg_len > MTK_NOR_PRG_CNT_MAX / 8)
> >>                        return false;
> >>        } else {
> >> -             prg_len = tx_len + op->dummy.nbytes;
> >> +             prg_len = tx_len + dummy_nbytes;
> >>                if (prg_len > MTK_NOR_PRG_CNT_MAX / 8)
> >>                        return false;
> >>        }
> >> @@ -244,15 +243,19 @@ static bool mtk_nor_match_prg(const struct spi_mem_op *op)
> >>   static void mtk_nor_adj_prg_size(struct spi_mem_op *op)
> >>   {
> >>        int tx_len, tx_left, prg_left;
> > 
> >> +     u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> >> +
> >> +     if (op->dummy.dtr)
> >> +             dummy_nbytes *= 2;
> > 
> > ditto
> > 
> >>
> >>        tx_len = op->cmd.nbytes + op->addr.nbytes;
> >>        if (op->data.dir == SPI_MEM_DATA_OUT) {
> >> -             tx_len += op->dummy.nbytes;
> >> +             tx_len += dummy_nbytes;
> >>                tx_left = MTK_NOR_REG_PRGDATA_MAX + 1 - tx_len;
> >>                if (op->data.nbytes > tx_left)
> >>                        op->data.nbytes = tx_left;
> >>        } else if (op->data.dir == SPI_MEM_DATA_IN) {
> >> -             prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - op->dummy.nbytes;
> >> +             prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - dummy_nbytes;
> >>                if (prg_left > MTK_NOR_REG_SHIFT_MAX + 1)
> >>                        prg_left = MTK_NOR_REG_SHIFT_MAX + 1;
> >>                if (op->data.nbytes > prg_left)
> >> @@ -312,7 +315,7 @@ static bool mtk_nor_supports_op(struct spi_mem *mem,
> >>                        break;
> >>                case SPI_MEM_DATA_OUT:
> >>                        if ((op->addr.buswidth == 1) &&
> >> -                         (op->dummy.nbytes == 0) &&
> >> +                         (op->dummy.ncycles == 0) &&
> >>                            (op->data.buswidth == 1))
> >>                                return true;
> >>                        break;
> >> @@ -515,17 +518,20 @@ static int mtk_nor_spi_mem_prg(struct mtk_nor *sp, const struct spi_mem_op *op)
> >>        int tx_len, prg_len;
> >>        int i, ret;
> >>        void __iomem *reg;
> > 
> >> -     u8 bufbyte;
> >> +     u8 bufbyte, dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> >> +
> >> +     if (op->dummy.dtr)
> >> +             dummy_nbytes *= 2;
> > 
> > ditto
> > 
> >>
> >>        tx_len = op->cmd.nbytes + op->addr.nbytes;
> >>
> >>        // count dummy bytes only if we need to write data after it
> >>        if (op->data.dir == SPI_MEM_DATA_OUT)
> >> -             tx_len += op->dummy.nbytes + op->data.nbytes;
> >> +             tx_len += dummy_nbytes + op->data.nbytes;
> >>        else if (op->data.dir == SPI_MEM_DATA_IN)
> >>                rx_len = op->data.nbytes;
> >>
> >> -     prg_len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes +
> >> +     prg_len = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes +
> >>                  op->data.nbytes;
> >>
> >>        // an invalid op may reach here if the caller calls exec_op without
> >> @@ -550,7 +556,7 @@ static int mtk_nor_spi_mem_prg(struct mtk_nor *sp, const struct spi_mem_op *op)
> >>        }
> >>
> >>        if (op->data.dir == SPI_MEM_DATA_OUT) {
> >> -             for (i = 0; i < op->dummy.nbytes; i++, reg_offset--) {
> >> +             for (i = 0; i < dummy_nbytes; i++, reg_offset--) {
> >>                        reg = sp->base + MTK_NOR_REG_PRGDATA(reg_offset);
> >>                        writeb(0, reg);
> >>                }
> > 
> > [...]
> > 
> >> diff --git a/drivers/spi/spi-zynq-qspi.c b/drivers/spi/spi-zynq-qspi.c
> >> index 78f31b61a2aa..84b7db85548c 100644
> >> --- a/drivers/spi/spi-zynq-qspi.c
> >> +++ b/drivers/spi/spi-zynq-qspi.c
> >> @@ -527,7 +527,10 @@ static int zynq_qspi_exec_mem_op(struct spi_mem *mem,
> >>   {
> >>        struct zynq_qspi *xqspi = spi_controller_get_devdata(mem->spi->master);
> >>        int err = 0, i;

> >> -     u8 *tmpbuf;
> >> +     u8 *tmpbuf, dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> > 
> > Separate line?

Too long. Split the declaration and initialization up.

> > 
> >> +
> >> +     if (op->dummy.dtr)
> >> +             dummy_nbytes *= 2;
> > 
> > Is DTR supported by the driver?
> > 
> 
> 

> Not from what I can see, but I was not 100% sure so I placed this if 
> statement here just in case.

spi_mem_default_supports_op() will return false for the DTR-available
transfers anyway. So the spi_mem_exec_op() method will fail right at
the start and this part will never be executed if the DTR-mode is
requested.

-Sergey

> 
> 
> 
> >>
> >>        dev_dbg(xqspi->dev, "cmd:%#x mode:%d.%d.%d.%d\n",
> >>                op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
> >> @@ -568,17 +571,17 @@ static int zynq_qspi_exec_mem_op(struct spi_mem *mem,
> >>                        err = -ETIMEDOUT;
> >>        }
> >>
> >> -     if (op->dummy.nbytes) {
> >> -             tmpbuf = kzalloc(op->dummy.nbytes, GFP_KERNEL);
> >> +     if (dummy_nbytes) {
> >> +             tmpbuf = kzalloc(dummy_nbytes, GFP_KERNEL);
> >>                if (!tmpbuf)
> >>                        return -ENOMEM;
> >>
> >> -             memset(tmpbuf, 0xff, op->dummy.nbytes);
> >> +             memset(tmpbuf, 0xff, dummy_nbytes);
> >>                reinit_completion(&xqspi->data_completion);
> >>                xqspi->txbuf = tmpbuf;
> >>                xqspi->rxbuf = NULL;
> >> -             xqspi->tx_bytes = op->dummy.nbytes;
> >> -             xqspi->rx_bytes = op->dummy.nbytes;
> >> +             xqspi->tx_bytes = dummy_nbytes;
> >> +             xqspi->rx_bytes = dummy_nbytes;
> >>                zynq_qspi_write_op(xqspi, ZYNQ_QSPI_FIFO_DEPTH, true);
> >>                zynq_qspi_write(xqspi, ZYNQ_QSPI_IEN_OFFSET,
> >>                                ZYNQ_QSPI_IXR_RXTX_MASK);
> >> diff --git a/drivers/spi/spi-zynqmp-gqspi.c b/drivers/spi/spi-zynqmp-gqspi.c
> >> index c760aac070e5..b41abadef9a6 100644
> >> --- a/drivers/spi/spi-zynqmp-gqspi.c
> >> +++ b/drivers/spi/spi-zynqmp-gqspi.c
> >> @@ -948,6 +948,10 @@ static int zynqmp_qspi_exec_op(struct spi_mem *mem,
> >>        u32 genfifoentry = 0;
> >>        u16 opcode = op->cmd.opcode;
> >>        u64 opaddr;
> > 
> >> +     u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
> >> +
> >> +     if (op->dummy.dtr)
> >> +             dummy_nbytes *= 2;
> > 
> > ditto
> > 
> >>
> >>        dev_dbg(xqspi->dev, "cmd:%#x mode:%d.%d.%d.%d\n",
> >>                op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
> >> @@ -1006,14 +1010,14 @@ static int zynqmp_qspi_exec_op(struct spi_mem *mem,
> >>                }
> >>        }
> >>
> >> -     if (op->dummy.nbytes) {
> >> +     if (dummy_nbytes) {
> >>                xqspi->txbuf = NULL;
> >>                xqspi->rxbuf = NULL;
> >>                /*
> >>                 * xqspi->bytes_to_transfer here represents the dummy circles
> >>                 * which need to be sent.
> >>                 */
> >> -             xqspi->bytes_to_transfer = op->dummy.nbytes * 8 / op->dummy.buswidth;
> >> +             xqspi->bytes_to_transfer = dummy_nbytes;
> >>                xqspi->bytes_to_receive = 0;
> >>                /*
> >>                 * Using op->data.buswidth instead of op->dummy.buswidth here because
> >> diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h
> >> index 2ba044d0d5e5..5fd45800af03 100644
> >> --- a/include/linux/spi/spi-mem.h
> >> +++ b/include/linux/spi/spi-mem.h
> >> @@ -29,9 +29,9 @@
> >>
> >>   #define SPI_MEM_OP_NO_ADDR   { }
> >>
> > 
> >> -#define SPI_MEM_OP_DUMMY(__nbytes, __buswidth)                       \
> >> +#define SPI_MEM_OP_DUMMY(__ncycles, __buswidth)              \
> >>        {                                                       \
> > 
> >> -             .nbytes = __nbytes,                             \
> >> +             .ncycles = __ncycles,                           \
> >>                .buswidth = __buswidth,                         \
> > 
> > Please make sure this update and the drivers/spi/spi-mem.c driver
> > alterations are coherent with the SPI Nand driver. See the macro usages:
> > include/linux/mtd/spinand.h: SPINAND_PAGE_READ_FROM_*().
> > 
> > -Sergey
> >
> 
> 
> Yes, indeed, I should have paid more attention here. As I have 
> previously said,  I simply replaced dummy.nbytes with the code sequences 
> you now see. I should have checked for SPI_MEM_OP_DUMMY usages as well 
> since I changed its definition. Thank you! :)
> 
> 
> >>        }
> >>
> >> @@ -83,8 +83,8 @@ enum spi_mem_data_dir {
> >>    *         Note that only @addr.nbytes are taken into account in this
> >>    *         address value, so users should make sure the value fits in the
> >>    *         assigned number of bytes.
> >> - * @dummy.nbytes: number of dummy bytes to send after an opcode or address. Can
> >> - *             be zero if the operation does not require dummy bytes
> >> + * @dummy.ncycles: number of dummy cycles after an opcode or address. Can
> >> + *              be zero if the operation does not require dummy cycles
> >>    * @dummy.buswidth: number of IO lanes used to transmit the dummy bytes
> >>    * @dummy.dtr: whether the dummy bytes should be sent in DTR mode or not
> >>    * @data.buswidth: number of IO lanes used to send/receive the data
> >> @@ -112,7 +112,7 @@ struct spi_mem_op {
> >>        } addr;
> >>
> >>        struct {
> >> -             u8 nbytes;
> >> +             u8 ncycles;
> >>                u8 buswidth;
> >>                u8 dtr : 1;
> >>        } dummy;
> >> --
> >> 2.34.1
> >>
> 
> 
> Regards,
> 	Sergiu

Sergiu Moga Sept. 27, 2022, 8:21 a.m. UTC | #7

On 26.09.2022 20:24, Serge Semin wrote:
> @Mark, @Tudor, @Pratyush, @Michael could you please join the
> discussion regarding the dummy.buswidth and dummy.dtr fields in the
> spi_mem_op structure?
> 
> On Mon, Sep 26, 2022 at 09:05:49AM +0000, [e-mail] wrote:
>> On 26.09.2022 01:03, Serge Semin wrote:
>>> Hello Sergiu
>>>
> 
> Sergiu, you didn't address all my comments. Please be more attentive.
> 

Hello Serge,

My apologies, I did take note of them :D. I said while addressing your 
comments for `drivers/spi/spi-dw-core.c` that I agree with the rest of 
the comments, as I did not find it productive to say something among the 
lines of "I agree" or "Noted" for each comment separately.


>>
>>
>> Hello Serge,
>>
>>
>>> On Sun, Sep 11, 2022 at 08:45:53PM +0300, Sergiu Moga wrote:
>>>> In order to properly represent the hardware functionality
>>>> in the core, avoid reconverting the number of dummy cycles
>>>> to the number of bytes and only work with the former.
>>>> Instead, let the drivers that do need this conversion do
>>>> it themselves.
>>>>
>>>> Signed-off-by: Sergiu Moga <[e-mail]>
>>>> ---
>>>>    drivers/mtd/spi-nor/core.c        | 22 ++++----------
>>>
>>> [...]
>>>
>>>>    drivers/spi/spi-dw-core.c         | 10 +++++--
>>>
>>> [...]
>>>
>>>>    drivers/spi/spi-mem.c             | 27 +++++++++++------
>>>
>>> [...]
>>>
>>>>    drivers/spi/spi-mtk-nor.c         | 48 +++++++++++++++++--------------
>>>
>>> [...]
>>>
>>>>    drivers/spi/spi-zynq-qspi.c       | 15 ++++++----
>>>>    drivers/spi/spi-zynqmp-gqspi.c    |  8 ++++--
>>>>    include/linux/spi/spi-mem.h       | 10 +++----
>>>>    25 files changed, 234 insertions(+), 147 deletions(-)
>>>>
>>>> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
>>>> index f2c64006f8d7..cc8ca824f912 100644
>>>> --- a/drivers/mtd/spi-nor/core.c
>>>> +++ b/drivers/mtd/spi-nor/core.c
>>>> @@ -88,7 +88,7 @@ void spi_nor_spimem_setup_op(const struct spi_nor *nor,
>>>>         if (op->addr.nbytes)
>>>>                 op->addr.buswidth = spi_nor_get_protocol_addr_nbits(proto);
>>>>
>>>
>>>
>>>
>>>> -     if (op->dummy.nbytes)
>>>> +     if (op->dummy.ncycles)
>>>>                 op->dummy.buswidth = spi_nor_get_protocol_addr_nbits(proto);
>>>>
>>>>         if (op->data.nbytes)
>>>> @@ -106,9 +106,6 @@ void spi_nor_spimem_setup_op(const struct spi_nor *nor,
>>>>                 op->dummy.dtr = true;
>>>>                 op->data.dtr = true;
>>>>
>>>> -             /* 2 bytes per clock cycle in DTR mode. */
>>>> -             op->dummy.nbytes *= 2;
>>>> -
>>>>                 ext = spi_nor_get_cmd_ext(nor, op);
>>>>                 op->cmd.opcode = (op->cmd.opcode << 8) | ext;
>>>>                 op->cmd.nbytes = 2;
>>>> @@ -207,10 +204,7 @@ static ssize_t spi_nor_spimem_read_data(struct spi_nor *nor, loff_t from,
>>>>
>>>>         spi_nor_spimem_setup_op(nor, &op, nor->read_proto);
>>>>
>>>> -     /* convert the dummy cycles to the number of bytes */
>>>> -     op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
>>>> -     if (spi_nor_protocol_is_dtr(nor->read_proto))
>>>> -             op.dummy.nbytes *= 2;
>>>> +     op.dummy.ncycles = nor->read_dummy;
>>>
>>> So according to this modification and what is done in the rest of the
>>> patch, the dummy part of the SPI-mem operations now contains the number
>>> of cycles only. Am I right to think that it means a number of dummy
>>> clock oscillations? (Judging from what I've seen in the HW-manuals of
>>> the SPI NOR memory devices most likely I am...)
>>
>>
>>
>> Yes, you are correct.
>>
>>
>>> If so the "ncycles" field
>>> is now free from the "data" semantic. Then what is the meaning of the
>>> "buswidth and "dtr" fields in the spi_mem_op.dummy field?
>>>
>>
>>
> 
>> It is still meaningful as it is used for the conversion by some drivers
>> to nbytes and I do not see how it goes out of the specification in any
>> way. So, at least for now, I do not see any reason to remove these fields.
> 
> I do see the way these fields are used in the SPI-mem drivers. I was
> wondering what do these bits mean in the framework of the SPI-mem
> core? AFAICS from the specification the dummy cycles are irrelevant to
> the data bus state. It says "the master tri-states the bus during
> 'dummy' cycles." If so I don't see a reason to have the DTR and
> buswidth fields in the spi_mem_op structure anymore. The number of
> cycles could be calculated right on the initialization stage based on
> the SPI NOR/NAND requirements.
> 
> @Mark, @Tudor, @Pratyush, what do you think?
> 
>>
>>
>>>>
>>>>         usebouncebuf = spi_nor_spimem_bounce(nor, &op);
>>>>
>>>> @@ -455,7 +449,7 @@ int spi_nor_read_sr(struct spi_nor *nor, u8 *sr)
>>>>
>>>>                 if (nor->reg_proto == SNOR_PROTO_8_8_8_DTR) {
>>>>                         op.addr.nbytes = nor->params->rdsr_addr_nbytes;
>>>> -                     op.dummy.nbytes = nor->params->rdsr_dummy;
>>>> +                     op.dummy.ncycles = nor->params->rdsr_dummy;
>>>>                         /*
>>>>                          * We don't want to read only one byte in DTR mode. So,
>>>>                          * read 2 and then discard the second byte.
>>>> @@ -1913,10 +1907,7 @@ static int spi_nor_spimem_check_readop(struct spi_nor *nor,
>>>>
>>>>         spi_nor_spimem_setup_op(nor, &op, read->proto);
>>>>
>>>> -     /* convert the dummy cycles to the number of bytes */
>>>> -     op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
>>>> -     if (spi_nor_protocol_is_dtr(nor->read_proto))
>>>> -             op.dummy.nbytes *= 2;
>>>> +     op.dummy.ncycles = nor->read_dummy;
>>>>
>>>>         return spi_nor_spimem_check_op(nor, &op);
>>>>    }
>>>> @@ -3034,10 +3025,7 @@ static int spi_nor_create_read_dirmap(struct spi_nor *nor)
>>>>
>>>>         spi_nor_spimem_setup_op(nor, op, nor->read_proto);
>>>>
>>>> -     /* convert the dummy cycles to the number of bytes */
>>>> -     op->dummy.nbytes = (nor->read_dummy * op->dummy.buswidth) / 8;
>>>> -     if (spi_nor_protocol_is_dtr(nor->read_proto))
>>>> -             op->dummy.nbytes *= 2;
>>>> +     op->dummy.ncycles = nor->read_dummy;
>>>>
>>>>         /*
>>>>          * Since spi_nor_spimem_setup_op() only sets buswidth when the number
>>>
>>> [...]
>>>
>>>> diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c
>>>> index f87d97ccd2d6..0ba5c7d0e66e 100644
>>>> --- a/drivers/spi/spi-dw-core.c
>>>> +++ b/drivers/spi/spi-dw-core.c
>>>> @@ -498,13 +498,17 @@ static bool dw_spi_supports_mem_op(struct spi_mem *mem,
>>>>    static int dw_spi_init_mem_buf(struct dw_spi *dws, const struct spi_mem_op *op)
>>>>    {
>>>>         unsigned int i, j, len;
>>>> -     u8 *out;
>>>> +     u8 *out, dummy_nbytes;
>>>>
>>>>         /*
>>>>          * Calculate the total length of the EEPROM command transfer and
>>>>          * either use the pre-allocated buffer or create a temporary one.
>>>>          */
>>>> -     len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
>>>
>>>> +     dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
>>>
>>> 1. What about using the BITS_PER_BYTE macro (linux/bits.h) here? Since
>>> you are adding a similar modification to so many drivers what about using
>>> that macro there too?
>>>
>>
>>
> 
>> AFAICT BIT_PER_BYTE is meant to transparently indicate how many bits per
>> byte an arch has. Although, there is no place in the kernel from what I
>> can see that has BITS_PER_BYTE with a value other than 8, you cannot
>> deny that there exist architectures whose number of bits per byte may be
>> different from 8.
> 
> Judging by the way the macro is declared it isn't platform specific.
> So no, the kernel always expects the byte having eight bits.
> 
>>
>> Meanwhile, the JESD216E specification tells us in the Terms and
>> definitions chapter that
>> "DWORD: Four consecutive 8-bit bytes used as the basic 32-bit building
>> block for headers and parameter tables." So it explicitly says that a
>> byte has 8 bits regardless of the arch.
> 
> Right. That's what the BITS_PER_BYTE macro is for.
> 
>>
>> Therefore, I do not agree with replacing 8 with the BITS_PER_BYTE macro
>> as, IMO, it does not represent the same thing as the number of bits per
>> byte that the terms and definitions of the JESD216E specification refer to.
> 
> It represents exactly the same in include/linux/bits.h .
> 
> Ideally it would be good to use it in all your updates since you touch
> the corresponding parts anyway. But at the very least I would insist on
> using the macro in the drivers which already have it utilized like
> spi-dw-*, spi-mtk-snfi, spi-mtk-nor.
> 


I guess you are right. I wrongly assumed it has something to do with 
plaforms. I checked with commit f7589f28d7dd4586b4e90ac3b2a180409669053a 
when it was first defined and I guess that yeah, it's not what I thought 
it was, my apologies :).


>>
>>
>>> 2. buswidth is supposed to be always 1 in this driver (see the
>>> dw_spi_supports_mem_op() method). So it can be dropped from the
>>> statement above.
>>>
>>> 3. Since the ncycles now contains a number of clock cycles there is no
>>> point in taking the SPI bus-width into account at all. What is
>>> meaningful is how many oscillations are supposed to be placed on the
>>> CLK line before the data is available. So the op->dummy.ncycles /
>>> BITS_PER_BYTE statement would be more appropriate here in any case.
>>>
>>
>>
> 
>> I can agee with this in the case of this driver, sure.
> 
> Ok. thanks.
> 
>>
>>
>>>> +     if (op->dummy.dtr)
>>>> +             dummy_nbytes *= 2;
>>>
>>> DTR is unsupported by the controller. See, no spi_controller_mem_caps
>>> initialized. So this part is redundant. The same is most likely
>>> applicable for some of the DTR-related updates in this patch too
>>> since the spi_controller_mem_caps structure is initialized in a few
>>> drivers only.
>>>
>>
>>
> 
>> Agreed. Initially, wherever I was not sure, I just placed this if
>> condition to avoid breaking anything in case the driver does support
>> DTR. The same goes for your other related observations to other driver
>> modifications, with which I agree :).
> 
> AFAICS the only drivers which support the DTR-capable transfers are
> the ones having the spi_controller_mem_caps structure defined with dtr
> set to true or the ones with custom SPI-mem ops. It means that the
> DTR-transfers are supported by the spi-mtk-snfi.c, spi-mxic.c,
> spi-cadence-quadspi.c and spi-intel.c drivers only. The rest of the
> SPI-controller drivers will fail to execute the SPI-mem ops with dtr
> flag set due to the spi_mem_default_supports_op() method semantics.
> 
>>
>>
>>>> +
>>>> +     len = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes;
>>>>         if (op->data.dir == SPI_MEM_DATA_OUT)
>>>>                 len += op->data.nbytes;
>>>>
>>>> @@ -525,7 +529,7 @@ static int dw_spi_init_mem_buf(struct dw_spi *dws, const struct spi_mem_op *op)
>>>>                 out[i] = DW_SPI_GET_BYTE(op->cmd.opcode, op->cmd.nbytes - i - 1);
>>>>         for (j = 0; j < op->addr.nbytes; ++i, ++j)
>>>>                 out[i] = DW_SPI_GET_BYTE(op->addr.val, op->addr.nbytes - j - 1);
>>>> -     for (j = 0; j < op->dummy.nbytes; ++i, ++j)
>>>> +     for (j = 0; j < dummy_nbytes; ++i, ++j)
>>>>                 out[i] = 0x0;
>>>>
>>>>         if (op->data.dir == SPI_MEM_DATA_OUT)
>>>
>>> [...]
>>>
>>>> diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
>>>> index 0c79193d9697..7b204963bb62 100644
>>>> --- a/drivers/spi/spi-mem.c
>>>> +++ b/drivers/spi/spi-mem.c
>>>> @@ -149,7 +149,7 @@ static bool spi_mem_check_buswidth(struct spi_mem *mem,
>>>>             spi_check_buswidth_req(mem, op->addr.buswidth, true))
>>>>                 return false;
>>>>
>>>> -     if (op->dummy.nbytes &&
>>>> +     if (op->dummy.ncycles &&
>>>>             spi_check_buswidth_req(mem, op->dummy.buswidth, true))
>>>>                 return false;
>>>>
>>>> @@ -202,7 +202,7 @@ static int spi_mem_check_op(const struct spi_mem_op *op)
>>>>                 return -EINVAL;
>>>>
>>>>         if ((op->addr.nbytes && !op->addr.buswidth) ||
>>>> -         (op->dummy.nbytes && !op->dummy.buswidth) ||
>>>> +         (op->dummy.ncycles && !op->dummy.buswidth) ||
>>>>             (op->data.nbytes && !op->data.buswidth))
>>>>                 return -EINVAL;
>>>>
>>>> @@ -315,7 +315,7 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
>>>
>>>>         struct spi_controller *ctlr = mem->spi->controller;
>>>>         struct spi_transfer xfers[4] = { };
>>>>         struct spi_message msg;
>>>> -     u8 *tmpbuf;
>>>> +     u8 *tmpbuf, dummy_nbytes;
>>>>         int ret;
>>>
> 
>>> Reverse xmas tree order?
> 
> Please take this note into account. Preserving the locally defined
> coding-style convention is a very useful practice. It retains the code
> uniformity, which improves readability and maintainability for just no
> price.
> 
>>>
>>>>
>>>>         ret = spi_mem_check_op(op);
>>>> @@ -343,7 +343,11 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
>>>>                         return ret;
>>>>         }
>>>>
>>>
>>>> -     tmpbufsize = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
>>>> +     dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
>>>
>>> So ncycles now indeed is a number of CLK line oscillations. This most
>>> likely will break the SPI Nand driver then, which still passes the
>>> number of bytes to the SPI_MEM_OP_DUMMY() macro.
>>>
>>>> +     if (op->dummy.dtr)
>>>> +             dummy_nbytes *= 2;
>>>
>>> Generic SPI-mem ops don't take the DTR mode into account. So I don't
>>> see this necessary.
>>>
>>
>>
> 
>> You may be right, but this part of the code does take into consideration
>> the number of dummy.nbytes to calculate the xfer length. Therefore,
>> shouldn't this code block also know if the number of dummy nbytes is
>> actually double the amount that it calculated through the conversion
>> formula?
> 
> Ok. This part turns to be debatable indeed. On the first glance the
> SPI-mem core doesn't anyhow handles the DTR-flag value. On the other
> hand SPI-controllers may have the dtr-capability flag set thus, for
> instance implicitly supporting the DTR transfers. Finally currently
> all the DTR-aware drivers are known to have the custom SPI-mem ops
> defined. So some aspects say for dropping the dummy.dtr field usage
> from here, some say against it. I'll leave it for you and @Mark,
> @Tudor, @Pratyush to decide.
> 



I am fine with this either way. I placed it here at first since I found 
it to be most appropriate here.



>>
>>
>>>> +
>>>> +     tmpbufsize = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes;
>>>>
>>>>         /*
>>>>          * Allocate a buffer to transmit the CMD, ADDR cycles with kmalloc() so
>>>> @@ -379,15 +383,15 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
>>>>                 totalxferlen += op->addr.nbytes;
>>>>         }
>>>>
>>>> -     if (op->dummy.nbytes) {
>>>> -             memset(tmpbuf + op->addr.nbytes + 1, 0xff, op->dummy.nbytes);
>>>> +     if (dummy_nbytes) {
>>>> +             memset(tmpbuf + op->addr.nbytes + 1, 0xff, dummy_nbytes);
>>>>                 xfers[xferpos].tx_buf = tmpbuf + op->addr.nbytes + 1;
>>>> -             xfers[xferpos].len = op->dummy.nbytes;
>>>> +             xfers[xferpos].len = dummy_nbytes;
>>>>                 xfers[xferpos].tx_nbits = op->dummy.buswidth;
>>>>                 xfers[xferpos].dummy_data = 1;
>>>>                 spi_message_add_tail(&xfers[xferpos], &msg);
>>>>                 xferpos++;
>>>> -             totalxferlen += op->dummy.nbytes;
>>>> +             totalxferlen += dummy_nbytes;
>>>>         }
>>>>
>>>>         if (op->data.nbytes) {
>>>> @@ -456,12 +460,17 @@ int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
>>>>    {
>>>
>>>>         struct spi_controller *ctlr = mem->spi->controller;
>>>>         size_t len;
>>>> +     u8 dummy_nbytes;
>>>
> 
>>> reverse xmas tree?
> 
> Please retain the local coding style convention.
> 
>>>
>>>>
>>>>         if (ctlr->mem_ops && ctlr->mem_ops->adjust_op_size)
>>>>                 return ctlr->mem_ops->adjust_op_size(mem, op);
>>>>
>>>> +     dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
>>>> +     if (op->dummy.dtr)
>>>> +             dummy_nbytes *= 2;
>>>> +
>>>>         if (!ctlr->mem_ops || !ctlr->mem_ops->exec_op) {
>>>> -             len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
>>>> +             len = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes;
>>>>
>>>>                 if (len > spi_max_transfer_size(mem->spi))
>>>>                         return -EINVAL;
>>>
>>> [...]
>>>
>>>> diff --git a/drivers/spi/spi-mtk-nor.c b/drivers/spi/spi-mtk-nor.c
>>>> index d167699a1a96..f6870c6e911a 100644
>>>> --- a/drivers/spi/spi-mtk-nor.c
>>>> +++ b/drivers/spi/spi-mtk-nor.c
>>>> @@ -171,23 +171,18 @@ static bool need_bounce(struct mtk_nor *sp, const struct spi_mem_op *op)
>>>>
>>>>    static bool mtk_nor_match_read(const struct spi_mem_op *op)
>>>>    {
>>>> -     int dummy = 0;
>>>> -
>>>> -     if (op->dummy.nbytes)
>>>> -             dummy = op->dummy.nbytes * BITS_PER_BYTE / op->dummy.buswidth;
>>>> -
>>>>         if ((op->data.buswidth == 2) || (op->data.buswidth == 4)) {
>>>>                 if (op->addr.buswidth == 1)
>>>> -                     return dummy == 8;
>>>> +                     return op->dummy.ncycles == 8;
>>>>                 else if (op->addr.buswidth == 2)
>>>> -                     return dummy == 4;
>>>> +                     return op->dummy.ncycles == 4;
>>>>                 else if (op->addr.buswidth == 4)
>>>> -                     return dummy == 6;
>>>> +                     return op->dummy.ncycles == 6;
>>>>         } else if ((op->addr.buswidth == 1) && (op->data.buswidth == 1)) {
>>>>                 if (op->cmd.opcode == 0x03)
>>>> -                     return dummy == 0;
>>>> +                     return op->dummy.ncycles == 0;
>>>>                 else if (op->cmd.opcode == 0x0b)
>>>> -                     return dummy == 8;
>>>> +                     return op->dummy.ncycles == 8;
>>>>         }
>>>>         return false;
>>>>    }
>>>> @@ -195,6 +190,10 @@ static bool mtk_nor_match_read(const struct spi_mem_op *op)
>>>>    static bool mtk_nor_match_prg(const struct spi_mem_op *op)
>>>>    {
>>>>         int tx_len, rx_len, prg_len, prg_left;
>>>
> 
> 
>>>> +     u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
>>>> +
>>>
>>> IMO it's better to move the initialization statement to a separate
>>> line here.
> 
> Again. The initialization statement is too long. It makes the code
> harder to read. Just split the declaration and initialization up.
> 



Alright, I did take note of it. As I previously said, I agree with all 
of your styling related comments.



>>>
>>>> +     if (op->dummy.dtr)
>>>> +             dummy_nbytes *= 2;
>>>
> 
>>> Does the MTK SPI driver support DTR? AFAICS it doesn't.
> 
> I'll give an answer. It doesn't. The spi_mem_exec_op() will return the
> -ENOTSUPP error if an SPI-mem op with any dtr flag set is requested.
> 



Alright, thanks.



>>>
>>>>
>>>>         // prg mode is spi-only.
>>>>         if ((op->cmd.buswidth > 1) || (op->addr.buswidth > 1) ||
>>>> @@ -205,7 +204,7 @@ static bool mtk_nor_match_prg(const struct spi_mem_op *op)
>>>>
>>>>         if (op->data.dir == SPI_MEM_DATA_OUT) {
>>>>                 // count dummy bytes only if we need to write data after it
>>>> -             tx_len += op->dummy.nbytes;
>>>> +             tx_len += dummy_nbytes;
>>>>
>>>>                 // leave at least one byte for data
>>>>                 if (tx_len > MTK_NOR_REG_PRGDATA_MAX)
>>>> @@ -221,7 +220,7 @@ static bool mtk_nor_match_prg(const struct spi_mem_op *op)
>>>>                         return false;
>>>>
>>>>                 rx_len = op->data.nbytes;
>>>> -             prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - op->dummy.nbytes;
>>>> +             prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - dummy_nbytes;
>>>>                 if (prg_left > MTK_NOR_REG_SHIFT_MAX + 1)
>>>>                         prg_left = MTK_NOR_REG_SHIFT_MAX + 1;
>>>>                 if (rx_len > prg_left) {
>>>> @@ -230,11 +229,11 @@ static bool mtk_nor_match_prg(const struct spi_mem_op *op)
>>>>                         rx_len = prg_left;
>>>>                 }
>>>>
>>>> -             prg_len = tx_len + op->dummy.nbytes + rx_len;
>>>> +             prg_len = tx_len + dummy_nbytes + rx_len;
>>>>                 if (prg_len > MTK_NOR_PRG_CNT_MAX / 8)
>>>>                         return false;
>>>>         } else {
>>>> -             prg_len = tx_len + op->dummy.nbytes;
>>>> +             prg_len = tx_len + dummy_nbytes;
>>>>                 if (prg_len > MTK_NOR_PRG_CNT_MAX / 8)
>>>>                         return false;
>>>>         }
>>>> @@ -244,15 +243,19 @@ static bool mtk_nor_match_prg(const struct spi_mem_op *op)
>>>>    static void mtk_nor_adj_prg_size(struct spi_mem_op *op)
>>>>    {
>>>>         int tx_len, tx_left, prg_left;
>>>
>>>> +     u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
>>>> +
>>>> +     if (op->dummy.dtr)
>>>> +             dummy_nbytes *= 2;
>>>
>>> ditto
>>>
>>>>
>>>>         tx_len = op->cmd.nbytes + op->addr.nbytes;
>>>>         if (op->data.dir == SPI_MEM_DATA_OUT) {
>>>> -             tx_len += op->dummy.nbytes;
>>>> +             tx_len += dummy_nbytes;
>>>>                 tx_left = MTK_NOR_REG_PRGDATA_MAX + 1 - tx_len;
>>>>                 if (op->data.nbytes > tx_left)
>>>>                         op->data.nbytes = tx_left;
>>>>         } else if (op->data.dir == SPI_MEM_DATA_IN) {
>>>> -             prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - op->dummy.nbytes;
>>>> +             prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - dummy_nbytes;
>>>>                 if (prg_left > MTK_NOR_REG_SHIFT_MAX + 1)
>>>>                         prg_left = MTK_NOR_REG_SHIFT_MAX + 1;
>>>>                 if (op->data.nbytes > prg_left)
>>>> @@ -312,7 +315,7 @@ static bool mtk_nor_supports_op(struct spi_mem *mem,
>>>>                         break;
>>>>                 case SPI_MEM_DATA_OUT:
>>>>                         if ((op->addr.buswidth == 1) &&
>>>> -                         (op->dummy.nbytes == 0) &&
>>>> +                         (op->dummy.ncycles == 0) &&
>>>>                             (op->data.buswidth == 1))
>>>>                                 return true;
>>>>                         break;
>>>> @@ -515,17 +518,20 @@ static int mtk_nor_spi_mem_prg(struct mtk_nor *sp, const struct spi_mem_op *op)
>>>>         int tx_len, prg_len;
>>>>         int i, ret;
>>>>         void __iomem *reg;
>>>
>>>> -     u8 bufbyte;
>>>> +     u8 bufbyte, dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
>>>> +
>>>> +     if (op->dummy.dtr)
>>>> +             dummy_nbytes *= 2;
>>>
>>> ditto
>>>
>>>>
>>>>         tx_len = op->cmd.nbytes + op->addr.nbytes;
>>>>
>>>>         // count dummy bytes only if we need to write data after it
>>>>         if (op->data.dir == SPI_MEM_DATA_OUT)
>>>> -             tx_len += op->dummy.nbytes + op->data.nbytes;
>>>> +             tx_len += dummy_nbytes + op->data.nbytes;
>>>>         else if (op->data.dir == SPI_MEM_DATA_IN)
>>>>                 rx_len = op->data.nbytes;
>>>>
>>>> -     prg_len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes +
>>>> +     prg_len = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes +
>>>>                   op->data.nbytes;
>>>>
>>>>         // an invalid op may reach here if the caller calls exec_op without
>>>> @@ -550,7 +556,7 @@ static int mtk_nor_spi_mem_prg(struct mtk_nor *sp, const struct spi_mem_op *op)
>>>>         }
>>>>
>>>>         if (op->data.dir == SPI_MEM_DATA_OUT) {
>>>> -             for (i = 0; i < op->dummy.nbytes; i++, reg_offset--) {
>>>> +             for (i = 0; i < dummy_nbytes; i++, reg_offset--) {
>>>>                         reg = sp->base + MTK_NOR_REG_PRGDATA(reg_offset);
>>>>                         writeb(0, reg);
>>>>                 }
>>>
>>> [...]
>>>
>>>> diff --git a/drivers/spi/spi-zynq-qspi.c b/drivers/spi/spi-zynq-qspi.c
>>>> index 78f31b61a2aa..84b7db85548c 100644
>>>> --- a/drivers/spi/spi-zynq-qspi.c
>>>> +++ b/drivers/spi/spi-zynq-qspi.c
>>>> @@ -527,7 +527,10 @@ static int zynq_qspi_exec_mem_op(struct spi_mem *mem,
>>>>    {
>>>>         struct zynq_qspi *xqspi = spi_controller_get_devdata(mem->spi->master);
>>>>         int err = 0, i;
> 
>>>> -     u8 *tmpbuf;
>>>> +     u8 *tmpbuf, dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
>>>
>>> Separate line?
> 
> Too long. Split the declaration and initialization up.
> 
>>>
>>>> +
>>>> +     if (op->dummy.dtr)
>>>> +             dummy_nbytes *= 2;
>>>
>>> Is DTR supported by the driver?
>>>
>>
>>
> 
>> Not from what I can see, but I was not 100% sure so I placed this if
>> statement here just in case.
> 
> spi_mem_default_supports_op() will return false for the DTR-available
> transfers anyway. So the spi_mem_exec_op() method will fail right at
> the start and this part will never be executed if the DTR-mode is
> requested.
> 
> -Sergey
> 


Noted.


Thanks,
	Sergiu


>>
>>
>>
>>>>
>>>>         dev_dbg(xqspi->dev, "cmd:%#x mode:%d.%d.%d.%d\n",
>>>>                 op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
>>>> @@ -568,17 +571,17 @@ static int zynq_qspi_exec_mem_op(struct spi_mem *mem,
>>>>                         err = -ETIMEDOUT;
>>>>         }
>>>>
>>>> -     if (op->dummy.nbytes) {
>>>> -             tmpbuf = kzalloc(op->dummy.nbytes, GFP_KERNEL);
>>>> +     if (dummy_nbytes) {
>>>> +             tmpbuf = kzalloc(dummy_nbytes, GFP_KERNEL);
>>>>                 if (!tmpbuf)
>>>>                         return -ENOMEM;
>>>>
>>>> -             memset(tmpbuf, 0xff, op->dummy.nbytes);
>>>> +             memset(tmpbuf, 0xff, dummy_nbytes);
>>>>                 reinit_completion(&xqspi->data_completion);
>>>>                 xqspi->txbuf = tmpbuf;
>>>>                 xqspi->rxbuf = NULL;
>>>> -             xqspi->tx_bytes = op->dummy.nbytes;
>>>> -             xqspi->rx_bytes = op->dummy.nbytes;
>>>> +             xqspi->tx_bytes = dummy_nbytes;
>>>> +             xqspi->rx_bytes = dummy_nbytes;
>>>>                 zynq_qspi_write_op(xqspi, ZYNQ_QSPI_FIFO_DEPTH, true);
>>>>                 zynq_qspi_write(xqspi, ZYNQ_QSPI_IEN_OFFSET,
>>>>                                 ZYNQ_QSPI_IXR_RXTX_MASK);
>>>> diff --git a/drivers/spi/spi-zynqmp-gqspi.c b/drivers/spi/spi-zynqmp-gqspi.c
>>>> index c760aac070e5..b41abadef9a6 100644
>>>> --- a/drivers/spi/spi-zynqmp-gqspi.c
>>>> +++ b/drivers/spi/spi-zynqmp-gqspi.c
>>>> @@ -948,6 +948,10 @@ static int zynqmp_qspi_exec_op(struct spi_mem *mem,
>>>>         u32 genfifoentry = 0;
>>>>         u16 opcode = op->cmd.opcode;
>>>>         u64 opaddr;
>>>
>>>> +     u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
>>>> +
>>>> +     if (op->dummy.dtr)
>>>> +             dummy_nbytes *= 2;
>>>
>>> ditto
>>>
>>>>
>>>>         dev_dbg(xqspi->dev, "cmd:%#x mode:%d.%d.%d.%d\n",
>>>>                 op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
>>>> @@ -1006,14 +1010,14 @@ static int zynqmp_qspi_exec_op(struct spi_mem *mem,
>>>>                 }
>>>>         }
>>>>
>>>> -     if (op->dummy.nbytes) {
>>>> +     if (dummy_nbytes) {
>>>>                 xqspi->txbuf = NULL;
>>>>                 xqspi->rxbuf = NULL;
>>>>                 /*
>>>>                  * xqspi->bytes_to_transfer here represents the dummy circles
>>>>                  * which need to be sent.
>>>>                  */
>>>> -             xqspi->bytes_to_transfer = op->dummy.nbytes * 8 / op->dummy.buswidth;
>>>> +             xqspi->bytes_to_transfer = dummy_nbytes;
>>>>                 xqspi->bytes_to_receive = 0;
>>>>                 /*
>>>>                  * Using op->data.buswidth instead of op->dummy.buswidth here because
>>>> diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h
>>>> index 2ba044d0d5e5..5fd45800af03 100644
>>>> --- a/include/linux/spi/spi-mem.h
>>>> +++ b/include/linux/spi/spi-mem.h
>>>> @@ -29,9 +29,9 @@
>>>>
>>>>    #define SPI_MEM_OP_NO_ADDR   { }
>>>>
>>>
>>>> -#define SPI_MEM_OP_DUMMY(__nbytes, __buswidth)                       \
>>>> +#define SPI_MEM_OP_DUMMY(__ncycles, __buswidth)              \
>>>>         {                                                       \
>>>
>>>> -             .nbytes = __nbytes,                             \
>>>> +             .ncycles = __ncycles,                           \
>>>>                 .buswidth = __buswidth,                         \
>>>
>>> Please make sure this update and the drivers/spi/spi-mem.c driver
>>> alterations are coherent with the SPI Nand driver. See the macro usages:
>>> include/linux/mtd/spinand.h: SPINAND_PAGE_READ_FROM_*().
>>>
>>> -Sergey
>>>
>>
>>
>> Yes, indeed, I should have paid more attention here. As I have
>> previously said,  I simply replaced dummy.nbytes with the code sequences
>> you now see. I should have checked for SPI_MEM_OP_DUMMY usages as well
>> since I changed its definition. Thank you! :)
>>
>>
>>>>         }
>>>>
>>>> @@ -83,8 +83,8 @@ enum spi_mem_data_dir {
>>>>     *         Note that only @addr.nbytes are taken into account in this
>>>>     *         address value, so users should make sure the value fits in the
>>>>     *         assigned number of bytes.
>>>> - * @dummy.nbytes: number of dummy bytes to send after an opcode or address. Can
>>>> - *             be zero if the operation does not require dummy bytes
>>>> + * @dummy.ncycles: number of dummy cycles after an opcode or address. Can
>>>> + *              be zero if the operation does not require dummy cycles
>>>>     * @dummy.buswidth: number of IO lanes used to transmit the dummy bytes
>>>>     * @dummy.dtr: whether the dummy bytes should be sent in DTR mode or not
>>>>     * @data.buswidth: number of IO lanes used to send/receive the data
>>>> @@ -112,7 +112,7 @@ struct spi_mem_op {
>>>>         } addr;
>>>>
>>>>         struct {
>>>> -             u8 nbytes;
>>>> +             u8 ncycles;
>>>>                 u8 buswidth;
>>>>                 u8 dtr : 1;
>>>>         } dummy;
>>>> --
>>>> 2.34.1
>>>>
>>
>>
>> Regards,
>>        Sergiu

Tudor Ambarus March 4, 2023, 5:59 a.m. UTC | #8

Hi,

Sergiu changed his interests, I'm going to send a new version of this
patch. We really need the conversion in SPI NOR as there are flashes
that require a number of dummy cycles that is not multiple of 8.

Cheers,
ta

Tudor Ambarus March 8, 2023, 9:04 a.m. UTC | #9

Hi, Sarge,

On 9/26/22 18:24, Serge Semin wrote:
>>>> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
>>>> index f2c64006f8d7..cc8ca824f912 100644
>>>> --- a/drivers/mtd/spi-nor/core.c
>>>> +++ b/drivers/mtd/spi-nor/core.c
>>>> @@ -88,7 +88,7 @@ void spi_nor_spimem_setup_op(const struct spi_nor *nor,
>>>>        if (op->addr.nbytes)
>>>>                op->addr.buswidth = spi_nor_get_protocol_addr_nbits(proto);
>>>>
>>>
>>>
>>>> -     if (op->dummy.nbytes)
>>>> +     if (op->dummy.ncycles)
>>>>                op->dummy.buswidth = spi_nor_get_protocol_addr_nbits(proto);
>>>>
>>>>        if (op->data.nbytes)
>>>> @@ -106,9 +106,6 @@ void spi_nor_spimem_setup_op(const struct spi_nor *nor,
>>>>                op->dummy.dtr = true;
>>>>                op->data.dtr = true;
>>>>
>>>> -             /* 2 bytes per clock cycle in DTR mode. */
>>>> -             op->dummy.nbytes *= 2;
>>>> -
>>>>                ext = spi_nor_get_cmd_ext(nor, op);
>>>>                op->cmd.opcode = (op->cmd.opcode << 8) | ext;
>>>>                op->cmd.nbytes = 2;
>>>> @@ -207,10 +204,7 @@ static ssize_t spi_nor_spimem_read_data(struct spi_nor *nor, loff_t from,
>>>>
>>>>        spi_nor_spimem_setup_op(nor, &op, nor->read_proto);
>>>>
>>>> -     /* convert the dummy cycles to the number of bytes */
>>>> -     op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
>>>> -     if (spi_nor_protocol_is_dtr(nor->read_proto))
>>>> -             op.dummy.nbytes *= 2;
>>>> +     op.dummy.ncycles = nor->read_dummy;
>>> So according to this modification and what is done in the rest of the
>>> patch, the dummy part of the SPI-mem operations now contains the number
>>> of cycles only. Am I right to think that it means a number of dummy
>>> clock oscillations? (Judging from what I've seen in the HW-manuals of
>>> the SPI NOR memory devices most likely I am...)
>>
>>
>> Yes, you are correct.
>>

I confirm.

>>
>>> If so the "ncycles" field
>>> is now free from the "data" semantic. Then what is the meaning of the
>>> "buswidth and "dtr" fields in the spi_mem_op.dummy field?
>>>
>>
>> It is still meaningful as it is used for the conversion by some drivers 
>> to nbytes and I do not see how it goes out of the specification in any 
>> way. So, at least for now, I do not see any reason to remove these fields.
> I do see the way these fields are used in the SPI-mem drivers. I was
> wondering what do these bits mean in the framework of the SPI-mem
> core? AFAICS from the specification the dummy cycles are irrelevant to
> the data bus state. It says "the master tri-states the bus during
> 'dummy' cycles." If so I don't see a reason to have the DTR and
> buswidth fields in the spi_mem_op structure anymore. The number of
> cycles could be calculated right on the initialization stage based on
> the SPI NOR/NAND requirements.
> 
> @Mark, @Tudor, @Pratyush, what do you think?
> 

In an ideal world, where both the controller and the device talk about
dummy number of cycles, I would agree with you, buswidth and dtr should
not be relevant for the number of dummy cycles. But it seems that there
are old controllers (e.g. spi-hisi-sfc-v3xx.c, spi-mt65xx.c, spi-mxic.c)
that support buswidths > 1 and work only with dummy nbytes, they are not
capable of specifying a smaller granularity (ncycles). Thus the older
controllers would have to convert the dummy ncycles to dummy nbytes.
Since mixed transfer modes are a thing (see jesd251, it talks about
4S-4D-4D), where single transfer mode (S) can be mixed with double
transfer mode (D) for a command, the controller would have to guess the
buswidth and dtr of the dummy. Shall they replicate the buswidth and dtr
of the address or of the data? There's no rule for that. So we're forced
to keep the dummy.{dtr, buswidth} fields by the old controllers that
don't understand dummy ncycles.

I'm going to send a v2 of this patch, I'll add you in To. Thanks for
taking the time to review this patch!

Cheers,
ta

Michael Walle March 9, 2023, 8:38 a.m. UTC | #10

> In an ideal world, where both the controller and the device talk about
> dummy number of cycles, I would agree with you, buswidth and dtr should
> not be relevant for the number of dummy cycles. But it seems that there
> are old controllers (e.g. spi-hisi-sfc-v3xx.c, spi-mt65xx.c, 
> spi-mxic.c)
> that support buswidths > 1 and work only with dummy nbytes, they are 
> not
> capable of specifying a smaller granularity (ncycles). Thus the older
> controllers would have to convert the dummy ncycles to dummy nbytes.
> Since mixed transfer modes are a thing (see jesd251, it talks about
> 4S-4D-4D), where single transfer mode (S) can be mixed with double
> transfer mode (D) for a command, the controller would have to guess the
> buswidth and dtr of the dummy. Shall they replicate the buswidth and 
> dtr
> of the address or of the data? There's no rule for that.

But in the end that doesn't matter because they are just dummy clock
cycles and the mode will only affect the data/address/command. 
Therefore,
the controller is free to choose the mode that suits it best.

But that begs the question, is ncycles in regard to DTR or SDR? That is,
are you counting just one type of edges or both the falling and rising
edges. The smallest granularity would be ncycles in regard of DTR. To 
me,
it's not obvious what the SEMPER Nano Flash [1] uses. I'd say we choose
the smallest granularty in spi-mem to be future proof and maybe provide
some spi-mem helper to help setting the cycles for SDR/DTR. As an 
example,
if you want to wait 4 cycles in SDR you'd have ncycles=8 in spi-mem.

So you won't need the mode nor the dtr property.

-michael

[1] 
https://www.infineon.com/dgdl/Infineon-S25FS256T_256Mb_SEMPER_Nano_Flash_Quad_SPI_1.8V-DataSheet-v01_00-EN.pdf?fileId=8ac78c8c80027ecd0180740c5a46707a

Tudor Ambarus March 9, 2023, 10:42 a.m. UTC | #11

On 09.03.2023 10:38, Michael Walle wrote:
>> In an ideal world, where both the controller and the device talk about
>> dummy number of cycles, I would agree with you, buswidth and dtr should
>> not be relevant for the number of dummy cycles. But it seems that there
>> are old controllers (e.g. spi-hisi-sfc-v3xx.c, spi-mt65xx.c, spi-mxic.c)
>> that support buswidths > 1 and work only with dummy nbytes, they are not
>> capable of specifying a smaller granularity (ncycles). Thus the older
>> controllers would have to convert the dummy ncycles to dummy nbytes.
>> Since mixed transfer modes are a thing (see jesd251, it talks about
>> 4S-4D-4D), where single transfer mode (S) can be mixed with double
>> transfer mode (D) for a command, the controller would have to guess the
>> buswidth and dtr of the dummy. Shall they replicate the buswidth and dtr
>> of the address or of the data? There's no rule for that.
> 
> But in the end that doesn't matter because they are just dummy clock
> cycles and the mode will only affect the data/address/command. Therefore,
> the controller is free to choose the mode that suits it best.
>  > But that begs the question, is ncycles in regard to DTR or SDR? That is,
> are you counting just one type of edges or both the falling and rising
> edges. The smallest granularity would be ncycles in regard of DTR. To me,
> it's not obvious what the SEMPER Nano Flash [1] uses. I'd say we choose
> the smallest granularty in spi-mem to be future proof and maybe provide
> some spi-mem helper to help setting the cycles for SDR/DTR. As an example,
> if you want to wait 4 cycles in SDR you'd have ncycles=8 in spi-mem.
> 

No, we can't invent our own measuring units. We have cycles and half 
cycles (regardless of the transfer mode used (STR, DTR)).

> So you won't need the mode nor the dtr property.
> 
> -michael
> 
> [1] 
> https://www.infineon.com/dgdl/Infineon-S25FS256T_256Mb_SEMPER_Nano_Flash_Quad_SPI_1.8V-DataSheet-v01_00-EN.pdf?fileId=8ac78c8c80027ecd0180740c5a46707a

Michael Walle March 9, 2023, 10:56 a.m. UTC | #12

Am 2023-03-09 11:42, schrieb Tudor Ambarus:
> On 09.03.2023 10:38, Michael Walle wrote:
>>> In an ideal world, where both the controller and the device talk 
>>> about
>>> dummy number of cycles, I would agree with you, buswidth and dtr 
>>> should
>>> not be relevant for the number of dummy cycles. But it seems that 
>>> there
>>> are old controllers (e.g. spi-hisi-sfc-v3xx.c, spi-mt65xx.c, 
>>> spi-mxic.c)
>>> that support buswidths > 1 and work only with dummy nbytes, they are 
>>> not
>>> capable of specifying a smaller granularity (ncycles). Thus the older
>>> controllers would have to convert the dummy ncycles to dummy nbytes.
>>> Since mixed transfer modes are a thing (see jesd251, it talks about
>>> 4S-4D-4D), where single transfer mode (S) can be mixed with double
>>> transfer mode (D) for a command, the controller would have to guess 
>>> the
>>> buswidth and dtr of the dummy. Shall they replicate the buswidth and 
>>> dtr
>>> of the address or of the data? There's no rule for that.
>> 
>> But in the end that doesn't matter because they are just dummy clock
>> cycles and the mode will only affect the data/address/command. 
>> Therefore,
>> the controller is free to choose the mode that suits it best.
>>  > But that begs the question, is ncycles in regard to DTR or SDR? 
>> That is,
>> are you counting just one type of edges or both the falling and rising
>> edges. The smallest granularity would be ncycles in regard of DTR. To 
>> me,
>> it's not obvious what the SEMPER Nano Flash [1] uses. I'd say we 
>> choose
>> the smallest granularty in spi-mem to be future proof and maybe 
>> provide
>> some spi-mem helper to help setting the cycles for SDR/DTR. As an 
>> example,
>> if you want to wait 4 cycles in SDR you'd have ncycles=8 in spi-mem.
>> 
> 
> No, we can't invent our own measuring units. We have cycles and half
> cycles (regardless of the transfer mode used (STR, DTR)).

That is basically what I was saying, just using the correct term.
Ok. So we don't need the dtr property, right? I'm still not sure,
what the semper nano flash uses. Half cycles? But according to your
naming you'd specify full cylces?

-michael

Tudor Ambarus March 9, 2023, 12:09 p.m. UTC | #13

On 3/9/23 10:56, Michael Walle wrote:
> Am 2023-03-09 11:42, schrieb Tudor Ambarus:
>> On 09.03.2023 10:38, Michael Walle wrote:
>>>> In an ideal world, where both the controller and the device talk about
>>>> dummy number of cycles, I would agree with you, buswidth and dtr should
>>>> not be relevant for the number of dummy cycles. But it seems that there
>>>> are old controllers (e.g. spi-hisi-sfc-v3xx.c, spi-mt65xx.c,
>>>> spi-mxic.c)
>>>> that support buswidths > 1 and work only with dummy nbytes, they are
>>>> not
>>>> capable of specifying a smaller granularity (ncycles). Thus the older
>>>> controllers would have to convert the dummy ncycles to dummy nbytes.
>>>> Since mixed transfer modes are a thing (see jesd251, it talks about
>>>> 4S-4D-4D), where single transfer mode (S) can be mixed with double
>>>> transfer mode (D) for a command, the controller would have to guess the
>>>> buswidth and dtr of the dummy. Shall they replicate the buswidth and
>>>> dtr
>>>> of the address or of the data? There's no rule for that.
>>>
>>> But in the end that doesn't matter because they are just dummy clock
>>> cycles and the mode will only affect the data/address/command.
>>> Therefore,
>>> the controller is free to choose the mode that suits it best.
>>>  > But that begs the question, is ncycles in regard to DTR or SDR?
>>> That is,
>>> are you counting just one type of edges or both the falling and rising
>>> edges. The smallest granularity would be ncycles in regard of DTR. To
>>> me,
>>> it's not obvious what the SEMPER Nano Flash [1] uses. I'd say we choose
>>> the smallest granularty in spi-mem to be future proof and maybe provide
>>> some spi-mem helper to help setting the cycles for SDR/DTR. As an
>>> example,
>>> if you want to wait 4 cycles in SDR you'd have ncycles=8 in spi-mem.
>>>
>>
>> No, we can't invent our own measuring units. We have cycles and half
>> cycles (regardless of the transfer mode used (STR, DTR)).
> 
> That is basically what I was saying, just using the correct term.
> Ok. So we don't need the dtr property, right? I'm still not sure,

We do.

As of now you can't specify 20 dummy cycles for READID in 8D-8D-8D mode
because all the layers treats dummy as bytes, whereas they should treat
it as cycles. One dummy byte in 8D-8D-8D means 16 dummy cycles. 20 dummy
cycles in 8D-8D-8D means one byte and a quarter? This is a non-sense.

As the code is now, SPI NAND uses dummy cycles that are multiple of 8.
SPI NOR requires a variable number of dummy cycles, there's no
restrictions. In SPI NOR we get from SFDP or datasheets the number of
dummy cycles, and in the code we convert them to dummy nbytes. Then when
we get at the controller side, the majority of the controllers undo the
operation, they take the dummy nbytes and convert them to dummy ncycles.
Isn't better to use dummy ncycles from the beginning?

The controllers that can talk in dummy ncycles don't need the
dummy.{buswidth, dtr} fields.

The controllers that can't talk in dummy cycles, but only on a "byte"
boundary need both buswidth and dtr fields. Assume a flash needs 32
dummy cycles for an op on 8D-8D-8D mode. If the controller does not have
the buswidth and dtr info, it can't convert the dummy ncycles to nbytes.
If he knows only that buswidth is 8, it will convert ncycles to 4 bytes.
If dtr is also specified it converts ncycles to 2 bytes.

> what the semper nano flash uses. Half cycles? But according to your

there's no spimem flash code that use half cycles for now.

> naming you'd specify full cylces?

A clock period, yes.

Hope it helps.
ta

Michael Walle March 9, 2023, 12:35 p.m. UTC | #14

Am 2023-03-09 13:09, schrieb Tudor Ambarus:
> On 3/9/23 10:56, Michael Walle wrote:
>> Am 2023-03-09 11:42, schrieb Tudor Ambarus:
>>> On 09.03.2023 10:38, Michael Walle wrote:
>>>>> In an ideal world, where both the controller and the device talk 
>>>>> about
>>>>> dummy number of cycles, I would agree with you, buswidth and dtr 
>>>>> should
>>>>> not be relevant for the number of dummy cycles. But it seems that 
>>>>> there
>>>>> are old controllers (e.g. spi-hisi-sfc-v3xx.c, spi-mt65xx.c,
>>>>> spi-mxic.c)
>>>>> that support buswidths > 1 and work only with dummy nbytes, they 
>>>>> are
>>>>> not
>>>>> capable of specifying a smaller granularity (ncycles). Thus the 
>>>>> older
>>>>> controllers would have to convert the dummy ncycles to dummy 
>>>>> nbytes.
>>>>> Since mixed transfer modes are a thing (see jesd251, it talks about
>>>>> 4S-4D-4D), where single transfer mode (S) can be mixed with double
>>>>> transfer mode (D) for a command, the controller would have to guess 
>>>>> the
>>>>> buswidth and dtr of the dummy. Shall they replicate the buswidth 
>>>>> and
>>>>> dtr
>>>>> of the address or of the data? There's no rule for that.
>>>> 
>>>> But in the end that doesn't matter because they are just dummy clock
>>>> cycles and the mode will only affect the data/address/command.
>>>> Therefore,
>>>> the controller is free to choose the mode that suits it best.
>>>>  > But that begs the question, is ncycles in regard to DTR or SDR?
>>>> That is,
>>>> are you counting just one type of edges or both the falling and 
>>>> rising
>>>> edges. The smallest granularity would be ncycles in regard of DTR. 
>>>> To
>>>> me,
>>>> it's not obvious what the SEMPER Nano Flash [1] uses. I'd say we 
>>>> choose
>>>> the smallest granularty in spi-mem to be future proof and maybe 
>>>> provide
>>>> some spi-mem helper to help setting the cycles for SDR/DTR. As an
>>>> example,
>>>> if you want to wait 4 cycles in SDR you'd have ncycles=8 in spi-mem.
>>>> 
>>> 
>>> No, we can't invent our own measuring units. We have cycles and half
>>> cycles (regardless of the transfer mode used (STR, DTR)).
>> 
>> That is basically what I was saying, just using the correct term.
>> Ok. So we don't need the dtr property, right? I'm still not sure,
> 
> We do.
> 
> As of now you can't specify 20 dummy cycles for READID in 8D-8D-8D mode
> because all the layers treats dummy as bytes, whereas they should treat
> it as cycles. One dummy byte in 8D-8D-8D means 16 dummy cycles. 20 
> dummy
> cycles in 8D-8D-8D means one byte and a quarter? This is a non-sense.

Agreed.

> As the code is now, SPI NAND uses dummy cycles that are multiple of 8.
> SPI NOR requires a variable number of dummy cycles, there's no
> restrictions. In SPI NOR we get from SFDP or datasheets the number of
> dummy cycles, and in the code we convert them to dummy nbytes. Then 
> when
> we get at the controller side, the majority of the controllers undo the
> operation, they take the dummy nbytes and convert them to dummy 
> ncycles.
> Isn't better to use dummy ncycles from the beginning?

Yes, but now we should define what *one* cycle is. And that it is 
defined
regardless of the mode, because the mode only affects the IO lines. But
a clock cycle refers to the clock line. [coming back to here] And as you
said one cycle is one full clock cycle, it is also independent of the 
dtr
setting.

> The controllers that can talk in dummy ncycles don't need the
> dummy.{buswidth, dtr} fields.
> 
> The controllers that can't talk in dummy cycles, but only on a "byte"
> boundary need both buswidth and dtr fields. Assume a flash needs 32
> dummy cycles for an op on 8D-8D-8D mode. If the controller does not 
> have
> the buswidth and dtr info, it can't convert the dummy ncycles to 
> nbytes.
> If he knows only that buswidth is 8, it will convert ncycles to 4 
> bytes.
> If dtr is also specified it converts ncycles to 2 bytes.

No they don't need it. Lets take your semper flash and assume it needs
12 latency cycles. SPI-NOR will set ncycles to 12 *regardless of the 
mode
or dtr setting*. The controller then knows we need 12 clock cycles. It 
has
then to figure out how that can be achieved. E.g. if it can only do the
"old" byte programming and is in quad mode, good for it. It will send 6
dummy bytes, which will result in 12 dummy clock cycles, because 1 byte
takes two clock cycles in quad SDR mode. If its in octal mode, send 12
bytes. If its in dual mode, send 3 bytes. Obiously, it cannot be in
single bit mode, because it cannot send 1.5 bytes..

If it's freely programmable, it will just tell the hardware to insert
12 dummy clock cycles.

>> what the semper nano flash uses. Half cycles? But according to your
> 
> there's no spimem flash code that use half cycles for now.

Ahh, I just saw the semper flash doesn't support DTR at all. Ok then,
makes things even simpler.

>> naming you'd specify full cylces?
> 
> A clock period, yes.

Ok.

-michael

Tudor Ambarus March 9, 2023, 1:23 p.m. UTC | #15

On 09.03.2023 14:35, Michael Walle wrote:
> Am 2023-03-09 13:09, schrieb Tudor Ambarus:
>> On 3/9/23 10:56, Michael Walle wrote:
>>> Am 2023-03-09 11:42, schrieb Tudor Ambarus:
>>>> On 09.03.2023 10:38, Michael Walle wrote:
>>>>>> In an ideal world, where both the controller and the device talk 
>>>>>> about
>>>>>> dummy number of cycles, I would agree with you, buswidth and dtr 
>>>>>> should
>>>>>> not be relevant for the number of dummy cycles. But it seems that 
>>>>>> there
>>>>>> are old controllers (e.g. spi-hisi-sfc-v3xx.c, spi-mt65xx.c,
>>>>>> spi-mxic.c)
>>>>>> that support buswidths > 1 and work only with dummy nbytes, they are
>>>>>> not
>>>>>> capable of specifying a smaller granularity (ncycles). Thus the older
>>>>>> controllers would have to convert the dummy ncycles to dummy nbytes.
>>>>>> Since mixed transfer modes are a thing (see jesd251, it talks about
>>>>>> 4S-4D-4D), where single transfer mode (S) can be mixed with double
>>>>>> transfer mode (D) for a command, the controller would have to 
>>>>>> guess the
>>>>>> buswidth and dtr of the dummy. Shall they replicate the buswidth and
>>>>>> dtr
>>>>>> of the address or of the data? There's no rule for that.
>>>>>
>>>>> But in the end that doesn't matter because they are just dummy clock
>>>>> cycles and the mode will only affect the data/address/command.
>>>>> Therefore,
>>>>> the controller is free to choose the mode that suits it best.
>>>>>  > But that begs the question, is ncycles in regard to DTR or SDR?
>>>>> That is,
>>>>> are you counting just one type of edges or both the falling and rising
>>>>> edges. The smallest granularity would be ncycles in regard of DTR. To
>>>>> me,
>>>>> it's not obvious what the SEMPER Nano Flash [1] uses. I'd say we 
>>>>> choose
>>>>> the smallest granularty in spi-mem to be future proof and maybe 
>>>>> provide
>>>>> some spi-mem helper to help setting the cycles for SDR/DTR. As an
>>>>> example,
>>>>> if you want to wait 4 cycles in SDR you'd have ncycles=8 in spi-mem.
>>>>>
>>>>
>>>> No, we can't invent our own measuring units. We have cycles and half
>>>> cycles (regardless of the transfer mode used (STR, DTR)).
>>>
>>> That is basically what I was saying, just using the correct term.
>>> Ok. So we don't need the dtr property, right? I'm still not sure,
>>
>> We do.
>>
>> As of now you can't specify 20 dummy cycles for READID in 8D-8D-8D mode
>> because all the layers treats dummy as bytes, whereas they should treat
>> it as cycles. One dummy byte in 8D-8D-8D means 16 dummy cycles. 20 dummy
>> cycles in 8D-8D-8D means one byte and a quarter? This is a non-sense.
> 
> Agreed.
> 
>> As the code is now, SPI NAND uses dummy cycles that are multiple of 8.
>> SPI NOR requires a variable number of dummy cycles, there's no
>> restrictions. In SPI NOR we get from SFDP or datasheets the number of
>> dummy cycles, and in the code we convert them to dummy nbytes. Then when
>> we get at the controller side, the majority of the controllers undo the
>> operation, they take the dummy nbytes and convert them to dummy ncycles.
>> Isn't better to use dummy ncycles from the beginning?
> 
> Yes, but now we should define what *one* cycle is. And that it is defined
> regardless of the mode, because the mode only affects the IO lines. But
> a clock cycle refers to the clock line. [coming back to here] And as you
> said one cycle is one full clock cycle, it is also independent of the dtr
> setting.
> 
>> The controllers that can talk in dummy ncycles don't need the
>> dummy.{buswidth, dtr} fields.
>>
>> The controllers that can't talk in dummy cycles, but only on a "byte"
>> boundary need both buswidth and dtr fields. Assume a flash needs 32
>> dummy cycles for an op on 8D-8D-8D mode. If the controller does not have
>> the buswidth and dtr info, it can't convert the dummy ncycles to nbytes.
>> If he knows only that buswidth is 8, it will convert ncycles to 4 bytes.
>> If dtr is also specified it converts ncycles to 2 bytes.
> 
> No they don't need it. Lets take your semper flash and assume it needs
> 12 latency cycles. SPI-NOR will set ncycles to 12 *regardless of the mode
> or dtr setting*. The controller then knows we need 12 clock cycles. It has
> then to figure out how that can be achieved. E.g. if it can only do the
> "old" byte programming and is in quad mode, good for it. It will send 6
> dummy bytes, which will result in 12 dummy clock cycles, because 1 byte
> takes two clock cycles in quad SDR mode. If its in octal mode, send 12
> bytes. If its in dual mode, send 3 bytes. Obiously, it cannot be in
> single bit mode, because it cannot send 1.5 bytes..
> 

You miss the fact that you can have 1-1-4. What buswidth do you use for 
dummy, the address buswidth or the data buswidth?

What happens if crazy protocols like 1S-1S-8D appear? What buswidth and 
transfer mode are you going to use for dummy?

And please don't tell me that "we're going to assume that dummy.buswidth 
= address.buswidth because that's what we currently do in SPI NOR", 
because I'm not convinced that the assumption is correct.

> If it's freely programmable, it will just tell the hardware to insert
> 12 dummy clock cycles.
> 
>>> what the semper nano flash uses. Half cycles? But according to your
>>
>> there's no spimem flash code that use half cycles for now.
> 
> Ahh, I just saw the semper flash doesn't support DTR at all. Ok then,
> makes things even simpler.
> 
>>> naming you'd specify full cylces?
>>
>> A clock period, yes.
> 
> Ok.
> 
> -michael

Michael Walle March 9, 2023, 1:33 p.m. UTC | #16

>>> The controllers that can talk in dummy ncycles don't need the
>>> dummy.{buswidth, dtr} fields.
>>> 
>>> The controllers that can't talk in dummy cycles, but only on a "byte"
>>> boundary need both buswidth and dtr fields. Assume a flash needs 32
>>> dummy cycles for an op on 8D-8D-8D mode. If the controller does not 
>>> have
>>> the buswidth and dtr info, it can't convert the dummy ncycles to 
>>> nbytes.
>>> If he knows only that buswidth is 8, it will convert ncycles to 4 
>>> bytes.
>>> If dtr is also specified it converts ncycles to 2 bytes.
>> 
>> No they don't need it. Lets take your semper flash and assume it needs
>> 12 latency cycles. SPI-NOR will set ncycles to 12 *regardless of the 
>> mode
>> or dtr setting*. The controller then knows we need 12 clock cycles. It 
>> has
>> then to figure out how that can be achieved. E.g. if it can only do 
>> the
>> "old" byte programming and is in quad mode, good for it. It will send 
>> 6
>> dummy bytes, which will result in 12 dummy clock cycles, because 1 
>> byte
>> takes two clock cycles in quad SDR mode. If its in octal mode, send 12
>> bytes. If its in dual mode, send 3 bytes. Obiously, it cannot be in
>> single bit mode, because it cannot send 1.5 bytes..
>> 
> 
> You miss the fact that you can have 1-1-4. What buswidth do you use
> for dummy, the address buswidth or the data buswidth?

Doesn't matter, does it? The driver is free to chose, 1, 4, or anything
else. You don't sample any data during the dummy phase.
To answer your question: single for instruction, single for address,
whatever you choose for dummy as long as there are ncycles space between
address and data, and quad for data.

Depending on the capabilites of the hardware it will likely be 1 or 4.

> What happens if crazy protocols like 1S-1S-8D appear? What buswidth
> and transfer mode are you going to use for dummy?

Also doesn't matter. What matters is how many dummy clock cycles you
do. Again, they don't depent on the mode. You just have to count
the clock cycles between the address and the data phase (and that is
what your ncycle parameter will tell the controller).

> And please don't tell me that "we're going to assume that
> dummy.buswidth = address.buswidth because that's what we currently do
> in SPI NOR", because I'm not convinced that the assumption is correct.

No, it doesn't matter :)

-michael

Tudor Ambarus March 9, 2023, 1:54 p.m. UTC | #17

On 09.03.2023 15:33, Michael Walle wrote:
>>>> The controllers that can talk in dummy ncycles don't need the
>>>> dummy.{buswidth, dtr} fields.
>>>>
>>>> The controllers that can't talk in dummy cycles, but only on a "byte"
>>>> boundary need both buswidth and dtr fields. Assume a flash needs 32
>>>> dummy cycles for an op on 8D-8D-8D mode. If the controller does not 
>>>> have
>>>> the buswidth and dtr info, it can't convert the dummy ncycles to 
>>>> nbytes.
>>>> If he knows only that buswidth is 8, it will convert ncycles to 4 
>>>> bytes.
>>>> If dtr is also specified it converts ncycles to 2 bytes.
>>>
>>> No they don't need it. Lets take your semper flash and assume it needs
>>> 12 latency cycles. SPI-NOR will set ncycles to 12 *regardless of the 
>>> mode
>>> or dtr setting*. The controller then knows we need 12 clock cycles. 
>>> It has
>>> then to figure out how that can be achieved. E.g. if it can only do the
>>> "old" byte programming and is in quad mode, good for it. It will send 6
>>> dummy bytes, which will result in 12 dummy clock cycles, because 1 byte
>>> takes two clock cycles in quad SDR mode. If its in octal mode, send 12
>>> bytes. If its in dual mode, send 3 bytes. Obiously, it cannot be in
>>> single bit mode, because it cannot send 1.5 bytes..
>>>
>>
>> You miss the fact that you can have 1-1-4. What buswidth do you use
>> for dummy, the address buswidth or the data buswidth?
> 
> Doesn't matter, does it? The driver is free to chose, 1, 4, or anything
> else. You don't sample any data during the dummy phase.
> To answer your question: single for instruction, single for address,
> whatever you choose for dummy as long as there are ncycles space between
> address and data, and quad for data.

Huh? How does the controller chose, based on what?

> 
> Depending on the capabilites of the hardware it will likely be 1 or 4.
> 
>> What happens if crazy protocols like 1S-1S-8D appear? What buswidth
>> and transfer mode are you going to use for dummy?
> 
> Also doesn't matter. What matters is how many dummy clock cycles you
> do. Again, they don't depent on the mode. You just have to count
> the clock cycles between the address and the data phase (and that is
> what your ncycle parameter will tell the controller).
> 
>> And please don't tell me that "we're going to assume that
>> dummy.buswidth = address.buswidth because that's what we currently do
>> in SPI NOR", because I'm not convinced that the assumption is correct.
> 
> No, it doesn't matter :)
> 
> -michael

Michael Walle March 9, 2023, 2:01 p.m. UTC | #18

Am 2023-03-09 14:54, schrieb Tudor Ambarus:
> On 09.03.2023 15:33, Michael Walle wrote:
>>>>> The controllers that can talk in dummy ncycles don't need the
>>>>> dummy.{buswidth, dtr} fields.
>>>>> 
>>>>> The controllers that can't talk in dummy cycles, but only on a 
>>>>> "byte"
>>>>> boundary need both buswidth and dtr fields. Assume a flash needs 32
>>>>> dummy cycles for an op on 8D-8D-8D mode. If the controller does not 
>>>>> have
>>>>> the buswidth and dtr info, it can't convert the dummy ncycles to 
>>>>> nbytes.
>>>>> If he knows only that buswidth is 8, it will convert ncycles to 4 
>>>>> bytes.
>>>>> If dtr is also specified it converts ncycles to 2 bytes.
>>>> 
>>>> No they don't need it. Lets take your semper flash and assume it 
>>>> needs
>>>> 12 latency cycles. SPI-NOR will set ncycles to 12 *regardless of the 
>>>> mode
>>>> or dtr setting*. The controller then knows we need 12 clock cycles. 
>>>> It has
>>>> then to figure out how that can be achieved. E.g. if it can only do 
>>>> the
>>>> "old" byte programming and is in quad mode, good for it. It will 
>>>> send 6
>>>> dummy bytes, which will result in 12 dummy clock cycles, because 1 
>>>> byte
>>>> takes two clock cycles in quad SDR mode. If its in octal mode, send 
>>>> 12
>>>> bytes. If its in dual mode, send 3 bytes. Obiously, it cannot be in
>>>> single bit mode, because it cannot send 1.5 bytes..
>>>> 
>>> 
>>> You miss the fact that you can have 1-1-4. What buswidth do you use
>>> for dummy, the address buswidth or the data buswidth?
>> 
>> Doesn't matter, does it? The driver is free to chose, 1, 4, or 
>> anything
>> else. You don't sample any data during the dummy phase.
>> To answer your question: single for instruction, single for address,
>> whatever you choose for dummy as long as there are ncycles space 
>> between
>> address and data, and quad for data.
> 
> Huh? How does the controller chose, based on what?

Based on its own capabilities. It can choose either way. In the end
what matters is how many clock cycles there are between the address
and data phase. And you only need to convey that information to the
SPI controller - your new ncycles.

-michael

>> Depending on the capabilites of the hardware it will likely be 1 or 4.
>> 
>>> What happens if crazy protocols like 1S-1S-8D appear? What buswidth
>>> and transfer mode are you going to use for dummy?
>> 
>> Also doesn't matter. What matters is how many dummy clock cycles you
>> do. Again, they don't depent on the mode. You just have to count
>> the clock cycles between the address and the data phase (and that is
>> what your ncycle parameter will tell the controller).
>> 
>>> And please don't tell me that "we're going to assume that
>>> dummy.buswidth = address.buswidth because that's what we currently do
>>> in SPI NOR", because I'm not convinced that the assumption is 
>>> correct.
>> 
>> No, it doesn't matter :)
>> 
>> -michael

Chuanhong Guo March 9, 2023, 2:19 p.m. UTC | #19

Hi!

On Thu, Mar 9, 2023 at 10:04 PM Michael Walle <[e-mail]> wrote:
>
> Am 2023-03-09 14:54, schrieb Tudor Ambarus:
> > On 09.03.2023 15:33, Michael Walle wrote:
> >>>>> The controllers that can talk in dummy ncycles don't need the
> >>>>> dummy.{buswidth, dtr} fields.
> >>>>>
> >>>>> The controllers that can't talk in dummy cycles, but only on a
> >>>>> "byte"
> >>>>> boundary need both buswidth and dtr fields. Assume a flash needs 32
> >>>>> dummy cycles for an op on 8D-8D-8D mode. If the controller does not
> >>>>> have
> >>>>> the buswidth and dtr info, it can't convert the dummy ncycles to
> >>>>> nbytes.
> >>>>> If he knows only that buswidth is 8, it will convert ncycles to 4
> >>>>> bytes.
> >>>>> If dtr is also specified it converts ncycles to 2 bytes.
> >>>>
> >>>> No they don't need it. Lets take your semper flash and assume it
> >>>> needs
> >>>> 12 latency cycles. SPI-NOR will set ncycles to 12 *regardless of the
> >>>> mode
> >>>> or dtr setting*. The controller then knows we need 12 clock cycles.
> >>>> It has
> >>>> then to figure out how that can be achieved. E.g. if it can only do
> >>>> the
> >>>> "old" byte programming and is in quad mode, good for it. It will
> >>>> send 6
> >>>> dummy bytes, which will result in 12 dummy clock cycles, because 1
> >>>> byte
> >>>> takes two clock cycles in quad SDR mode. If its in octal mode, send
> >>>> 12
> >>>> bytes. If its in dual mode, send 3 bytes. Obiously, it cannot be in
> >>>> single bit mode, because it cannot send 1.5 bytes..
> >>>>
> >>>
> >>> You miss the fact that you can have 1-1-4. What buswidth do you use
> >>> for dummy, the address buswidth or the data buswidth?
> >>
> >> Doesn't matter, does it? The driver is free to chose, 1, 4, or
> >> anything
> >> else. You don't sample any data during the dummy phase.
> >> To answer your question: single for instruction, single for address,
> >> whatever you choose for dummy as long as there are ncycles space
> >> between
> >> address and data, and quad for data.
> >
> > Huh? How does the controller chose, based on what?
>
> Based on its own capabilities. It can choose either way. In the end
> what matters is how many clock cycles there are between the address
> and data phase. And you only need to convey that information to the
> SPI controller - your new ncycles.

It does matter. Controller may be designed to actively drive
MOSI/WP/HOLD during single-spi dummy cycles and WP/HOLD
during dual-spi dummy cycles. If the pin modes between the
controller and device mismatched, worst case scenario
the chip may get fried.

Tudor Ambarus March 9, 2023, 3:41 p.m. UTC | #20

On 09.03.2023 16:01, Michael Walle wrote:
> Am 2023-03-09 14:54, schrieb Tudor Ambarus:
>> On 09.03.2023 15:33, Michael Walle wrote:
>>>>>> The controllers that can talk in dummy ncycles don't need the
>>>>>> dummy.{buswidth, dtr} fields.
>>>>>>
>>>>>> The controllers that can't talk in dummy cycles, but only on a "byte"
>>>>>> boundary need both buswidth and dtr fields. Assume a flash needs 32
>>>>>> dummy cycles for an op on 8D-8D-8D mode. If the controller does 
>>>>>> not have
>>>>>> the buswidth and dtr info, it can't convert the dummy ncycles to 
>>>>>> nbytes.
>>>>>> If he knows only that buswidth is 8, it will convert ncycles to 4 
>>>>>> bytes.
>>>>>> If dtr is also specified it converts ncycles to 2 bytes.
>>>>>
>>>>> No they don't need it. Lets take your semper flash and assume it needs
>>>>> 12 latency cycles. SPI-NOR will set ncycles to 12 *regardless of 
>>>>> the mode
>>>>> or dtr setting*. The controller then knows we need 12 clock cycles. 
>>>>> It has
>>>>> then to figure out how that can be achieved. E.g. if it can only do 
>>>>> the
>>>>> "old" byte programming and is in quad mode, good for it. It will 
>>>>> send 6
>>>>> dummy bytes, which will result in 12 dummy clock cycles, because 1 
>>>>> byte
>>>>> takes two clock cycles in quad SDR mode. If its in octal mode, send 12
>>>>> bytes. If its in dual mode, send 3 bytes. Obiously, it cannot be in
>>>>> single bit mode, because it cannot send 1.5 bytes..
>>>>>
>>>>
>>>> You miss the fact that you can have 1-1-4. What buswidth do you use
>>>> for dummy, the address buswidth or the data buswidth?
>>>
>>> Doesn't matter, does it? The driver is free to chose, 1, 4, or anything
>>> else. You don't sample any data during the dummy phase.
>>> To answer your question: single for instruction, single for address,
>>> whatever you choose for dummy as long as there are ncycles space between
>>> address and data, and quad for data.
>>
>> Huh? How does the controller chose, based on what?
> 
> Based on its own capabilities. It can choose either way. In the end

Okay, I'll go again through all the spi controllers and check if we can
determine the dummy nbytes based on controller caps. Thanks!

> what matters is how many clock cycles there are between the address
> and data phase. And you only need to convey that information to the
> SPI controller - your new ncycles.
> 
> -michael
> 
>>> Depending on the capabilites of the hardware it will likely be 1 or 4.
>>>
>>>> What happens if crazy protocols like 1S-1S-8D appear? What buswidth
>>>> and transfer mode are you going to use for dummy?
>>>
>>> Also doesn't matter. What matters is how many dummy clock cycles you
>>> do. Again, they don't depent on the mode. You just have to count
>>> the clock cycles between the address and the data phase (and that is
>>> what your ncycle parameter will tell the controller).
>>>
>>>> And please don't tell me that "we're going to assume that
>>>> dummy.buswidth = address.buswidth because that's what we currently do
>>>> in SPI NOR", because I'm not convinced that the assumption is correct.
>>>
>>> No, it doesn't matter :)
>>>
>>> -michael

Michael Walle March 9, 2023, 3:41 p.m. UTC | #21

Am 2023-03-09 15:19, schrieb Chuanhong Guo:
> Hi!
> 
> On Thu, Mar 9, 2023 at 10:04 PM Michael Walle <[e-mail]> wrote:
>> 
>> Am 2023-03-09 14:54, schrieb Tudor Ambarus:
>> > On 09.03.2023 15:33, Michael Walle wrote:
>> >>>>> The controllers that can talk in dummy ncycles don't need the
>> >>>>> dummy.{buswidth, dtr} fields.
>> >>>>>
>> >>>>> The controllers that can't talk in dummy cycles, but only on a
>> >>>>> "byte"
>> >>>>> boundary need both buswidth and dtr fields. Assume a flash needs 32
>> >>>>> dummy cycles for an op on 8D-8D-8D mode. If the controller does not
>> >>>>> have
>> >>>>> the buswidth and dtr info, it can't convert the dummy ncycles to
>> >>>>> nbytes.
>> >>>>> If he knows only that buswidth is 8, it will convert ncycles to 4
>> >>>>> bytes.
>> >>>>> If dtr is also specified it converts ncycles to 2 bytes.
>> >>>>
>> >>>> No they don't need it. Lets take your semper flash and assume it
>> >>>> needs
>> >>>> 12 latency cycles. SPI-NOR will set ncycles to 12 *regardless of the
>> >>>> mode
>> >>>> or dtr setting*. The controller then knows we need 12 clock cycles.
>> >>>> It has
>> >>>> then to figure out how that can be achieved. E.g. if it can only do
>> >>>> the
>> >>>> "old" byte programming and is in quad mode, good for it. It will
>> >>>> send 6
>> >>>> dummy bytes, which will result in 12 dummy clock cycles, because 1
>> >>>> byte
>> >>>> takes two clock cycles in quad SDR mode. If its in octal mode, send
>> >>>> 12
>> >>>> bytes. If its in dual mode, send 3 bytes. Obiously, it cannot be in
>> >>>> single bit mode, because it cannot send 1.5 bytes..
>> >>>>
>> >>>
>> >>> You miss the fact that you can have 1-1-4. What buswidth do you use
>> >>> for dummy, the address buswidth or the data buswidth?
>> >>
>> >> Doesn't matter, does it? The driver is free to chose, 1, 4, or
>> >> anything
>> >> else. You don't sample any data during the dummy phase.
>> >> To answer your question: single for instruction, single for address,
>> >> whatever you choose for dummy as long as there are ncycles space
>> >> between
>> >> address and data, and quad for data.
>> >
>> > Huh? How does the controller chose, based on what?
>> 
>> Based on its own capabilities. It can choose either way. In the end
>> what matters is how many clock cycles there are between the address
>> and data phase. And you only need to convey that information to the
>> SPI controller - your new ncycles.
> 
> It does matter. Controller may be designed to actively drive
> MOSI/WP/HOLD during single-spi dummy cycles and WP/HOLD
> during dual-spi dummy cycles. If the pin modes between the
> controller and device mismatched, worst case scenario
> the chip may get fried.

Interesting. But most of the time you'll have to do what the
spi controller supports. Only if its freely programmable,
then according to your comment you'd choose the buswidth of
the data phase to be on the safe side.

Btw. this is not what spi-nor is doing right now.

-michael

Patch

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index f2c64006f8d7..cc8ca824f912 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -88,7 +88,7 @@  void spi_nor_spimem_setup_op(const struct spi_nor *nor,
 	if (op->addr.nbytes)
 		op->addr.buswidth = spi_nor_get_protocol_addr_nbits(proto);
 
-	if (op->dummy.nbytes)
+	if (op->dummy.ncycles)
 		op->dummy.buswidth = spi_nor_get_protocol_addr_nbits(proto);
 
 	if (op->data.nbytes)
@@ -106,9 +106,6 @@  void spi_nor_spimem_setup_op(const struct spi_nor *nor,
 		op->dummy.dtr = true;
 		op->data.dtr = true;
 
-		/* 2 bytes per clock cycle in DTR mode. */
-		op->dummy.nbytes *= 2;
-
 		ext = spi_nor_get_cmd_ext(nor, op);
 		op->cmd.opcode = (op->cmd.opcode << 8) | ext;
 		op->cmd.nbytes = 2;
@@ -207,10 +204,7 @@  static ssize_t spi_nor_spimem_read_data(struct spi_nor *nor, loff_t from,
 
 	spi_nor_spimem_setup_op(nor, &op, nor->read_proto);
 
-	/* convert the dummy cycles to the number of bytes */
-	op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
-	if (spi_nor_protocol_is_dtr(nor->read_proto))
-		op.dummy.nbytes *= 2;
+	op.dummy.ncycles = nor->read_dummy;
 
 	usebouncebuf = spi_nor_spimem_bounce(nor, &op);
 
@@ -455,7 +449,7 @@  int spi_nor_read_sr(struct spi_nor *nor, u8 *sr)
 
 		if (nor->reg_proto == SNOR_PROTO_8_8_8_DTR) {
 			op.addr.nbytes = nor->params->rdsr_addr_nbytes;
-			op.dummy.nbytes = nor->params->rdsr_dummy;
+			op.dummy.ncycles = nor->params->rdsr_dummy;
 			/*
 			 * We don't want to read only one byte in DTR mode. So,
 			 * read 2 and then discard the second byte.
@@ -1913,10 +1907,7 @@  static int spi_nor_spimem_check_readop(struct spi_nor *nor,
 
 	spi_nor_spimem_setup_op(nor, &op, read->proto);
 
-	/* convert the dummy cycles to the number of bytes */
-	op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
-	if (spi_nor_protocol_is_dtr(nor->read_proto))
-		op.dummy.nbytes *= 2;
+	op.dummy.ncycles = nor->read_dummy;
 
 	return spi_nor_spimem_check_op(nor, &op);
 }
@@ -3034,10 +3025,7 @@  static int spi_nor_create_read_dirmap(struct spi_nor *nor)
 
 	spi_nor_spimem_setup_op(nor, op, nor->read_proto);
 
-	/* convert the dummy cycles to the number of bytes */
-	op->dummy.nbytes = (nor->read_dummy * op->dummy.buswidth) / 8;
-	if (spi_nor_protocol_is_dtr(nor->read_proto))
-		op->dummy.nbytes *= 2;
+	op->dummy.ncycles = nor->read_dummy;
 
 	/*
 	 * Since spi_nor_spimem_setup_op() only sets buswidth when the number
diff --git a/drivers/mtd/spi-nor/micron-st.c b/drivers/mtd/spi-nor/micron-st.c
index 3c9681a3f7a3..840a9fc0a888 100644
--- a/drivers/mtd/spi-nor/micron-st.c
+++ b/drivers/mtd/spi-nor/micron-st.c
@@ -337,7 +337,7 @@  static int micron_st_nor_read_fsr(struct spi_nor *nor, u8 *fsr)
 
 		if (nor->reg_proto == SNOR_PROTO_8_8_8_DTR) {
 			op.addr.nbytes = nor->params->rdsr_addr_nbytes;
-			op.dummy.nbytes = nor->params->rdsr_dummy;
+			op.dummy.ncycles = nor->params->rdsr_dummy;
 			/*
 			 * We don't want to read only one byte in DTR mode. So,
 			 * read 2 and then discard the second byte.
diff --git a/drivers/spi/atmel-quadspi.c b/drivers/spi/atmel-quadspi.c
index 976a217e356d..9a86525e7a4a 100644
--- a/drivers/spi/atmel-quadspi.c
+++ b/drivers/spi/atmel-quadspi.c
@@ -286,7 +286,7 @@  static bool atmel_qspi_supports_op(struct spi_mem *mem,
 
 	/* special case not supported by hardware */
 	if (op->addr.nbytes == 2 && op->cmd.buswidth != op->addr.buswidth &&
-	    op->dummy.nbytes == 0)
+	    op->dummy.ncycles == 0)
 		return false;
 
 	return true;
@@ -308,8 +308,8 @@  static int atmel_qspi_set_cfg(struct atmel_qspi *aq,
 		return mode;
 	ifr |= atmel_qspi_modes[mode].config;
 
-	if (op->dummy.nbytes)
-		dummy_cycles = op->dummy.nbytes * 8 / op->dummy.buswidth;
+	if (op->dummy.ncycles)
+		dummy_cycles = op->dummy.ncycles;
 
 	/*
 	 * The controller allows 24 and 32-bit addressing while NAND-flash
diff --git a/drivers/spi/spi-aspeed-smc.c b/drivers/spi/spi-aspeed-smc.c
index 3e891bf22470..2d50d50a9303 100644
--- a/drivers/spi/spi-aspeed-smc.c
+++ b/drivers/spi/spi-aspeed-smc.c
@@ -231,7 +231,7 @@  static ssize_t aspeed_spi_read_user(struct aspeed_spi_chip *chip,
 				    u64 offset, size_t len, void *buf)
 {
 	int io_mode = aspeed_spi_get_io_mode(op);
-	u8 dummy = 0xFF;
+	u8 dummy = 0xFF, dummy_nbytes;
 	int i;
 	int ret;
 
@@ -241,8 +241,12 @@  static ssize_t aspeed_spi_read_user(struct aspeed_spi_chip *chip,
 	if (ret < 0)
 		return ret;
 
-	if (op->dummy.buswidth && op->dummy.nbytes) {
-		for (i = 0; i < op->dummy.nbytes / op->dummy.buswidth; i++)
+	if (op->dummy.buswidth && op->dummy.ncycles) {
+		dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+		if (op->dummy.dtr)
+			dummy_nbytes *= 2;
+
+		for (i = 0; i < dummy_nbytes / op->dummy.buswidth; i++)
 			aspeed_spi_write_to_ahb(chip->ahb_base, &dummy,	sizeof(dummy));
 	}
 
@@ -270,6 +274,8 @@  static ssize_t aspeed_spi_write_user(struct aspeed_spi_chip *chip,
 /* support for 1-1-1, 1-1-2 or 1-1-4 */
 static bool aspeed_spi_supports_op(struct spi_mem *mem, const struct spi_mem_op *op)
 {
+	u8 dummy_nbytes;
+
 	if (op->cmd.buswidth > 1)
 		return false;
 
@@ -280,8 +286,12 @@  static bool aspeed_spi_supports_op(struct spi_mem *mem, const struct spi_mem_op
 			return false;
 	}
 
-	if (op->dummy.nbytes != 0) {
-		if (op->dummy.buswidth > 1 || op->dummy.nbytes > 7)
+	if (op->dummy.ncycles != 0) {
+		dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+		if (op->dummy.dtr)
+			dummy_nbytes *= 2;
+
+		if (op->dummy.buswidth > 1 || dummy_nbytes > 7)
 			return false;
 	}
 
@@ -306,7 +316,7 @@  static int do_aspeed_spi_exec_op(struct spi_mem *mem, const struct spi_mem_op *o
 		chip->cs, op->data.dir == SPI_MEM_DATA_IN ? "read" : "write",
 		op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
 		op->dummy.buswidth, op->data.buswidth,
-		op->addr.nbytes, op->dummy.nbytes, op->data.nbytes);
+		op->addr.nbytes, op->dummy.ncycles, op->data.nbytes);
 
 	addr_mode = readl(aspi->regs + CE_CTRL_REG);
 	addr_mode_backup = addr_mode;
@@ -327,8 +337,8 @@  static int do_aspeed_spi_exec_op(struct spi_mem *mem, const struct spi_mem_op *o
 			ctl_val |= CTRL_IO_ADDRESS_4B;
 	}
 
-	if (op->dummy.nbytes)
-		ctl_val |= CTRL_IO_DUMMY_SET(op->dummy.nbytes / op->dummy.buswidth);
+	if (op->dummy.ncycles)
+		ctl_val |= CTRL_IO_DUMMY_SET(op->dummy.ncycles / 8);
 
 	if (op->data.nbytes)
 		ctl_val |= aspeed_spi_get_io_mode(op);
@@ -564,7 +574,7 @@  static int aspeed_spi_dirmap_create(struct spi_mem_dirmap_desc *desc)
 		desc->info.offset, desc->info.offset + desc->info.length,
 		op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
 		op->dummy.buswidth, op->data.buswidth,
-		op->addr.nbytes, op->dummy.nbytes);
+		op->addr.nbytes, op->dummy.ncycles);
 
 	chip->clk_freq = desc->mem->spi->max_speed_hz;
 
@@ -584,8 +594,8 @@  static int aspeed_spi_dirmap_create(struct spi_mem_dirmap_desc *desc)
 		op->cmd.opcode << CTRL_COMMAND_SHIFT |
 		CTRL_IO_MODE_READ;
 
-	if (op->dummy.nbytes)
-		ctl_val |= CTRL_IO_DUMMY_SET(op->dummy.nbytes / op->dummy.buswidth);
+	if (op->dummy.ncycles)
+		ctl_val |= CTRL_IO_DUMMY_SET(op->dummy.ncycles / 8);
 
 	/* Tune 4BYTE address mode */
 	if (op->addr.nbytes) {
diff --git a/drivers/spi/spi-ath79.c b/drivers/spi/spi-ath79.c
index 607e7a49fb89..70bdb1eb42a2 100644
--- a/drivers/spi/spi-ath79.c
+++ b/drivers/spi/spi-ath79.c
@@ -145,7 +145,7 @@  static int ath79_exec_mem_op(struct spi_mem *mem,
 
 	/* Only use for fast-read op. */
 	if (op->cmd.opcode != 0x0b || op->data.dir != SPI_MEM_DATA_IN ||
-	    op->addr.nbytes != 3 || op->dummy.nbytes != 1)
+	    op->addr.nbytes != 3 || op->dummy.ncycles != 8)
 		return -ENOTSUPP;
 
 	/* disable GPIO mode */
diff --git a/drivers/spi/spi-bcm-qspi.c b/drivers/spi/spi-bcm-qspi.c
index cad2d55dcd3d..143e411c1523 100644
--- a/drivers/spi/spi-bcm-qspi.c
+++ b/drivers/spi/spi-bcm-qspi.c
@@ -428,8 +428,8 @@  static int bcm_qspi_bspi_set_flex_mode(struct bcm_qspi *qspi,
 	if (addrlen == BSPI_ADDRLEN_4BYTES)
 		bpp = BSPI_BPP_ADDR_SELECT_MASK;
 
-	if (op->dummy.nbytes)
-		bpp |= (op->dummy.nbytes * 8) / op->dummy.buswidth;
+	if (op->dummy.ncycles)
+		bpp |= op->dummy.ncycles;
 
 	switch (width) {
 	case SPI_NBITS_SINGLE:
@@ -1153,12 +1153,16 @@  static int bcm_qspi_mspi_exec_mem_op(struct spi_device *spi,
 	struct spi_master *master = spi->master;
 	struct bcm_qspi *qspi = spi_master_get_devdata(master);
 	struct spi_transfer t[2];
-	u8 cmd[6] = { };
+	u8 cmd[6] = { }, dummy_nbytes;
 	int ret, i;
 
 	memset(cmd, 0, sizeof(cmd));
 	memset(t, 0, sizeof(t));
 
+	dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+	if (op->dummy.dtr)
+		dummy_nbytes *= 2;
+
 	/* tx */
 	/* opcode is in cmd[0] */
 	cmd[0] = op->cmd.opcode;
@@ -1166,7 +1170,7 @@  static int bcm_qspi_mspi_exec_mem_op(struct spi_device *spi,
 		cmd[1 + i] = op->addr.val >> (8 * (op->addr.nbytes - i - 1));
 
 	t[0].tx_buf = cmd;
-	t[0].len = op->addr.nbytes + op->dummy.nbytes + 1;
+	t[0].len = op->addr.nbytes + dummy_nbytes + 1;
 	t[0].bits_per_word = spi->bits_per_word;
 	t[0].tx_nbits = op->cmd.buswidth;
 	/* lets mspi know that this is not last transfer */
diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c
index 72b1a5a2298c..2af43ba4a2cb 100644
--- a/drivers/spi/spi-cadence-quadspi.c
+++ b/drivers/spi/spi-cadence-quadspi.c
@@ -356,12 +356,10 @@  static unsigned int cqspi_calc_dummy(const struct spi_mem_op *op)
 {
 	unsigned int dummy_clk;
 
-	if (!op->dummy.nbytes)
+	if (!op->dummy.ncycles)
 		return 0;
 
-	dummy_clk = op->dummy.nbytes * (8 / op->dummy.buswidth);
-	if (op->cmd.dtr)
-		dummy_clk /= 2;
+	dummy_clk = op->dummy.ncycles;
 
 	return dummy_clk;
 }
@@ -1333,7 +1331,7 @@  static bool cqspi_supports_mem_op(struct spi_mem *mem,
 	 */
 	all_true = op->cmd.dtr &&
 		   (!op->addr.nbytes || op->addr.dtr) &&
-		   (!op->dummy.nbytes || op->dummy.dtr) &&
+		   (!op->dummy.ncycles || op->dummy.dtr) &&
 		   (!op->data.nbytes || op->data.dtr);
 
 	all_false = !op->cmd.dtr && !op->addr.dtr && !op->dummy.dtr &&
diff --git a/drivers/spi/spi-cadence-xspi.c b/drivers/spi/spi-cadence-xspi.c
index 3ab19be83095..8575e4c2ed7a 100644
--- a/drivers/spi/spi-cadence-xspi.c
+++ b/drivers/spi/spi-cadence-xspi.c
@@ -177,7 +177,10 @@ 
 #define CDNS_XSPI_CMD_FLD_DSEQ_CMD_3(op) ( \
 	FIELD_PREP(CDNS_XSPI_CMD_DSEQ_R3_DCNT_H, \
 		((op)->data.nbytes >> 16) & 0xffff) | \
-	FIELD_PREP(CDNS_XSPI_CMD_DSEQ_R3_NUM_OF_DUMMY, (op)->dummy.nbytes * 8))
+	FIELD_PREP(CDNS_XSPI_CMD_DSEQ_R3_NUM_OF_DUMMY, \
+		((op)->dummy.dtr ? \
+		((op)->dummy.ncycles * (op)->dummy.buswidth * 2) : \
+		((op)->dummy.ncycles * (op)->dummy.buswidth))))
 
 #define CDNS_XSPI_CMD_FLD_DSEQ_CMD_4(op, chipsel) ( \
 	FIELD_PREP(CDNS_XSPI_CMD_DSEQ_R4_BANK, chipsel) | \
diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c
index f87d97ccd2d6..0ba5c7d0e66e 100644
--- a/drivers/spi/spi-dw-core.c
+++ b/drivers/spi/spi-dw-core.c
@@ -498,13 +498,17 @@  static bool dw_spi_supports_mem_op(struct spi_mem *mem,
 static int dw_spi_init_mem_buf(struct dw_spi *dws, const struct spi_mem_op *op)
 {
 	unsigned int i, j, len;
-	u8 *out;
+	u8 *out, dummy_nbytes;
 
 	/*
 	 * Calculate the total length of the EEPROM command transfer and
 	 * either use the pre-allocated buffer or create a temporary one.
 	 */
-	len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
+	dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+	if (op->dummy.dtr)
+		dummy_nbytes *= 2;
+
+	len = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes;
 	if (op->data.dir == SPI_MEM_DATA_OUT)
 		len += op->data.nbytes;
 
@@ -525,7 +529,7 @@  static int dw_spi_init_mem_buf(struct dw_spi *dws, const struct spi_mem_op *op)
 		out[i] = DW_SPI_GET_BYTE(op->cmd.opcode, op->cmd.nbytes - i - 1);
 	for (j = 0; j < op->addr.nbytes; ++i, ++j)
 		out[i] = DW_SPI_GET_BYTE(op->addr.val, op->addr.nbytes - j - 1);
-	for (j = 0; j < op->dummy.nbytes; ++i, ++j)
+	for (j = 0; j < dummy_nbytes; ++i, ++j)
 		out[i] = 0x0;
 
 	if (op->data.dir == SPI_MEM_DATA_OUT)
diff --git a/drivers/spi/spi-fsl-qspi.c b/drivers/spi/spi-fsl-qspi.c
index 46ae46a944c5..897e8f11ccd1 100644
--- a/drivers/spi/spi-fsl-qspi.c
+++ b/drivers/spi/spi-fsl-qspi.c
@@ -369,6 +369,7 @@  static bool fsl_qspi_supports_op(struct spi_mem *mem,
 				 const struct spi_mem_op *op)
 {
 	struct fsl_qspi *q = spi_controller_get_devdata(mem->spi->master);
+	u8 dummy_nbytes;
 	int ret;
 
 	ret = fsl_qspi_check_buswidth(q, op->cmd.buswidth);
@@ -376,7 +377,7 @@  static bool fsl_qspi_supports_op(struct spi_mem *mem,
 	if (op->addr.nbytes)
 		ret |= fsl_qspi_check_buswidth(q, op->addr.buswidth);
 
-	if (op->dummy.nbytes)
+	if (op->dummy.ncycles)
 		ret |= fsl_qspi_check_buswidth(q, op->dummy.buswidth);
 
 	if (op->data.nbytes)
@@ -389,14 +390,17 @@  static bool fsl_qspi_supports_op(struct spi_mem *mem,
 	 * The number of instructions needed for the op, needs
 	 * to fit into a single LUT entry.
 	 */
+	dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+	if (op->dummy.dtr)
+		dummy_nbytes *= 2;
+
 	if (op->addr.nbytes +
-	   (op->dummy.nbytes ? 1:0) +
+	   (dummy_nbytes ? 1:0) +
 	   (op->data.nbytes ? 1:0) > 6)
 		return false;
 
 	/* Max 64 dummy clock cycles supported */
-	if (op->dummy.nbytes &&
-	    (op->dummy.nbytes * 8 / op->dummy.buswidth > 64))
+	if (op->dummy.ncycles && op->dummy.ncycles > 64)
 		return false;
 
 	/* Max data length, check controller limits and alignment */
@@ -437,11 +441,10 @@  static void fsl_qspi_prepare_lut(struct fsl_qspi *q,
 		lutidx++;
 	}
 
-	if (op->dummy.nbytes) {
+	if (op->dummy.ncycles) {
 		lutval[lutidx / 2] |= LUT_DEF(lutidx, LUT_DUMMY,
 					      LUT_PAD(op->dummy.buswidth),
-					      op->dummy.nbytes * 8 /
-					      op->dummy.buswidth);
+					      op->dummy.ncycles);
 		lutidx++;
 	}
 
diff --git a/drivers/spi/spi-hisi-sfc-v3xx.c b/drivers/spi/spi-hisi-sfc-v3xx.c
index d3a23b1c2a4c..5b6994eb7c8b 100644
--- a/drivers/spi/spi-hisi-sfc-v3xx.c
+++ b/drivers/spi/spi-hisi-sfc-v3xx.c
@@ -276,6 +276,7 @@  static int hisi_sfc_v3xx_start_bus(struct hisi_sfc_v3xx_host *host,
 {
 	int len = op->data.nbytes, buswidth_mode;
 	u32 config = 0;
+	u8 dummy_nbytes;
 
 	if (op->addr.nbytes)
 		config |= HISI_SFC_V3XX_CMD_CFG_ADDR_EN_MSK;
@@ -302,7 +303,10 @@  static int hisi_sfc_v3xx_start_bus(struct hisi_sfc_v3xx_host *host,
 	if (op->data.dir == SPI_MEM_DATA_IN)
 		config |= HISI_SFC_V3XX_CMD_CFG_RW_MSK;
 
-	config |= op->dummy.nbytes << HISI_SFC_V3XX_CMD_CFG_DUMMY_CNT_OFF |
+	dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+	if (op->dummy.dtr)
+		dummy_nbytes *= 2;
+	config |= dummy_nbytes << HISI_SFC_V3XX_CMD_CFG_DUMMY_CNT_OFF |
 		  chip_select << HISI_SFC_V3XX_CMD_CFG_CS_SEL_OFF |
 		  HISI_SFC_V3XX_CMD_CFG_START_MSK;
 
diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
index 0c79193d9697..7b204963bb62 100644
--- a/drivers/spi/spi-mem.c
+++ b/drivers/spi/spi-mem.c
@@ -149,7 +149,7 @@  static bool spi_mem_check_buswidth(struct spi_mem *mem,
 	    spi_check_buswidth_req(mem, op->addr.buswidth, true))
 		return false;
 
-	if (op->dummy.nbytes &&
+	if (op->dummy.ncycles &&
 	    spi_check_buswidth_req(mem, op->dummy.buswidth, true))
 		return false;
 
@@ -202,7 +202,7 @@  static int spi_mem_check_op(const struct spi_mem_op *op)
 		return -EINVAL;
 
 	if ((op->addr.nbytes && !op->addr.buswidth) ||
-	    (op->dummy.nbytes && !op->dummy.buswidth) ||
+	    (op->dummy.ncycles && !op->dummy.buswidth) ||
 	    (op->data.nbytes && !op->data.buswidth))
 		return -EINVAL;
 
@@ -315,7 +315,7 @@  int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
 	struct spi_controller *ctlr = mem->spi->controller;
 	struct spi_transfer xfers[4] = { };
 	struct spi_message msg;
-	u8 *tmpbuf;
+	u8 *tmpbuf, dummy_nbytes;
 	int ret;
 
 	ret = spi_mem_check_op(op);
@@ -343,7 +343,11 @@  int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
 			return ret;
 	}
 
-	tmpbufsize = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
+	dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+	if (op->dummy.dtr)
+		dummy_nbytes *= 2;
+
+	tmpbufsize = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes;
 
 	/*
 	 * Allocate a buffer to transmit the CMD, ADDR cycles with kmalloc() so
@@ -379,15 +383,15 @@  int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
 		totalxferlen += op->addr.nbytes;
 	}
 
-	if (op->dummy.nbytes) {
-		memset(tmpbuf + op->addr.nbytes + 1, 0xff, op->dummy.nbytes);
+	if (dummy_nbytes) {
+		memset(tmpbuf + op->addr.nbytes + 1, 0xff, dummy_nbytes);
 		xfers[xferpos].tx_buf = tmpbuf + op->addr.nbytes + 1;
-		xfers[xferpos].len = op->dummy.nbytes;
+		xfers[xferpos].len = dummy_nbytes;
 		xfers[xferpos].tx_nbits = op->dummy.buswidth;
 		xfers[xferpos].dummy_data = 1;
 		spi_message_add_tail(&xfers[xferpos], &msg);
 		xferpos++;
-		totalxferlen += op->dummy.nbytes;
+		totalxferlen += dummy_nbytes;
 	}
 
 	if (op->data.nbytes) {
@@ -456,12 +460,17 @@  int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
 {
 	struct spi_controller *ctlr = mem->spi->controller;
 	size_t len;
+	u8 dummy_nbytes;
 
 	if (ctlr->mem_ops && ctlr->mem_ops->adjust_op_size)
 		return ctlr->mem_ops->adjust_op_size(mem, op);
 
+	dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+	if (op->dummy.dtr)
+		dummy_nbytes *= 2;
+
 	if (!ctlr->mem_ops || !ctlr->mem_ops->exec_op) {
-		len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
+		len = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes;
 
 		if (len > spi_max_transfer_size(mem->spi))
 			return -EINVAL;
diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c
index 0a3b9f7eed30..22d002acebe8 100644
--- a/drivers/spi/spi-mt65xx.c
+++ b/drivers/spi/spi-mt65xx.c
@@ -845,9 +845,13 @@  static int mtk_spi_mem_adjust_op_size(struct spi_mem *mem,
 				      struct spi_mem_op *op)
 {
 	int opcode_len;
+	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+
+	if (op->dummy.dtr)
+		dummy_nbytes *= 2;
 
 	if (op->data.dir != SPI_MEM_NO_DATA) {
-		opcode_len = 1 + op->addr.nbytes + op->dummy.nbytes;
+		opcode_len = 1 + op->addr.nbytes + dummy_nbytes;
 		if (opcode_len + op->data.nbytes > MTK_SPI_IPM_PACKET_SIZE) {
 			op->data.nbytes = MTK_SPI_IPM_PACKET_SIZE - opcode_len;
 			/* force data buffer dma-aligned. */
@@ -861,14 +865,19 @@  static int mtk_spi_mem_adjust_op_size(struct spi_mem *mem,
 static bool mtk_spi_mem_supports_op(struct spi_mem *mem,
 				    const struct spi_mem_op *op)
 {
+	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+
+	if (op->dummy.dtr)
+		dummy_nbytes *= 2;
+
 	if (!spi_mem_default_supports_op(mem, op))
 		return false;
 
-	if (op->addr.nbytes && op->dummy.nbytes &&
+	if (op->addr.nbytes && dummy_nbytes &&
 	    op->addr.buswidth != op->dummy.buswidth)
 		return false;
 
-	if (op->addr.nbytes + op->dummy.nbytes > 16)
+	if (op->addr.nbytes + dummy_nbytes > 16)
 		return false;
 
 	if (op->data.nbytes > MTK_SPI_IPM_PACKET_SIZE) {
@@ -942,6 +951,10 @@  static int mtk_spi_mem_exec_op(struct spi_mem *mem,
 	u32 reg_val, nio, tx_size;
 	char *tx_tmp_buf, *rx_tmp_buf;
 	int ret = 0;
+	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+
+	if (op->dummy.dtr)
+		dummy_nbytes *= 2;
 
 	mdata->use_spimem = true;
 	reinit_completion(&mdata->spimem_done);
@@ -957,8 +970,8 @@  static int mtk_spi_mem_exec_op(struct spi_mem *mem,
 
 	/* addr & dummy byte len */
 	reg_val &= ~SPI_CFG3_IPM_ADDR_BYTELEN_MASK;
-	if (op->addr.nbytes || op->dummy.nbytes)
-		reg_val |= (op->addr.nbytes + op->dummy.nbytes) <<
+	if (op->addr.nbytes || dummy_nbytes)
+		reg_val |= (op->addr.nbytes + dummy_nbytes) <<
 			    SPI_CFG3_IPM_ADDR_BYTELEN_OFFSET;
 
 	/* data byte len */
@@ -971,7 +984,7 @@  static int mtk_spi_mem_exec_op(struct spi_mem *mem,
 		mtk_spi_setup_packet(mem->spi->master);
 	}
 
-	if (op->addr.nbytes || op->dummy.nbytes) {
+	if (op->addr.nbytes || dummy_nbytes) {
 		if (op->addr.buswidth == 1 || op->dummy.buswidth == 1)
 			reg_val |= SPI_CFG3_IPM_XMODE_EN;
 		else
@@ -999,7 +1012,7 @@  static int mtk_spi_mem_exec_op(struct spi_mem *mem,
 		reg_val &= ~SPI_CFG3_IPM_HALF_DUPLEX_DIR;
 	writel(reg_val, mdata->base + SPI_CFG3_IPM_REG);
 
-	tx_size = 1 + op->addr.nbytes + op->dummy.nbytes;
+	tx_size = 1 + op->addr.nbytes + dummy_nbytes;
 	if (op->data.dir == SPI_MEM_DATA_OUT)
 		tx_size += op->data.nbytes;
 
@@ -1021,13 +1034,13 @@  static int mtk_spi_mem_exec_op(struct spi_mem *mem,
 					(8 * (op->addr.nbytes - i - 1));
 	}
 
-	if (op->dummy.nbytes)
+	if (dummy_nbytes)
 		memset(tx_tmp_buf + op->addr.nbytes + 1,
 		       0xff,
-		       op->dummy.nbytes);
+		       dummy_nbytes);
 
 	if (op->data.nbytes && op->data.dir == SPI_MEM_DATA_OUT)
-		memcpy(tx_tmp_buf + op->dummy.nbytes + op->addr.nbytes + 1,
+		memcpy(tx_tmp_buf + dummy_nbytes + op->addr.nbytes + 1,
 		       op->data.buf.out,
 		       op->data.nbytes);
 
diff --git a/drivers/spi/spi-mtk-nor.c b/drivers/spi/spi-mtk-nor.c
index d167699a1a96..f6870c6e911a 100644
--- a/drivers/spi/spi-mtk-nor.c
+++ b/drivers/spi/spi-mtk-nor.c
@@ -171,23 +171,18 @@  static bool need_bounce(struct mtk_nor *sp, const struct spi_mem_op *op)
 
 static bool mtk_nor_match_read(const struct spi_mem_op *op)
 {
-	int dummy = 0;
-
-	if (op->dummy.nbytes)
-		dummy = op->dummy.nbytes * BITS_PER_BYTE / op->dummy.buswidth;
-
 	if ((op->data.buswidth == 2) || (op->data.buswidth == 4)) {
 		if (op->addr.buswidth == 1)
-			return dummy == 8;
+			return op->dummy.ncycles == 8;
 		else if (op->addr.buswidth == 2)
-			return dummy == 4;
+			return op->dummy.ncycles == 4;
 		else if (op->addr.buswidth == 4)
-			return dummy == 6;
+			return op->dummy.ncycles == 6;
 	} else if ((op->addr.buswidth == 1) && (op->data.buswidth == 1)) {
 		if (op->cmd.opcode == 0x03)
-			return dummy == 0;
+			return op->dummy.ncycles == 0;
 		else if (op->cmd.opcode == 0x0b)
-			return dummy == 8;
+			return op->dummy.ncycles == 8;
 	}
 	return false;
 }
@@ -195,6 +190,10 @@  static bool mtk_nor_match_read(const struct spi_mem_op *op)
 static bool mtk_nor_match_prg(const struct spi_mem_op *op)
 {
 	int tx_len, rx_len, prg_len, prg_left;
+	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+
+	if (op->dummy.dtr)
+		dummy_nbytes *= 2;
 
 	// prg mode is spi-only.
 	if ((op->cmd.buswidth > 1) || (op->addr.buswidth > 1) ||
@@ -205,7 +204,7 @@  static bool mtk_nor_match_prg(const struct spi_mem_op *op)
 
 	if (op->data.dir == SPI_MEM_DATA_OUT) {
 		// count dummy bytes only if we need to write data after it
-		tx_len += op->dummy.nbytes;
+		tx_len += dummy_nbytes;
 
 		// leave at least one byte for data
 		if (tx_len > MTK_NOR_REG_PRGDATA_MAX)
@@ -221,7 +220,7 @@  static bool mtk_nor_match_prg(const struct spi_mem_op *op)
 			return false;
 
 		rx_len = op->data.nbytes;
-		prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - op->dummy.nbytes;
+		prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - dummy_nbytes;
 		if (prg_left > MTK_NOR_REG_SHIFT_MAX + 1)
 			prg_left = MTK_NOR_REG_SHIFT_MAX + 1;
 		if (rx_len > prg_left) {
@@ -230,11 +229,11 @@  static bool mtk_nor_match_prg(const struct spi_mem_op *op)
 			rx_len = prg_left;
 		}
 
-		prg_len = tx_len + op->dummy.nbytes + rx_len;
+		prg_len = tx_len + dummy_nbytes + rx_len;
 		if (prg_len > MTK_NOR_PRG_CNT_MAX / 8)
 			return false;
 	} else {
-		prg_len = tx_len + op->dummy.nbytes;
+		prg_len = tx_len + dummy_nbytes;
 		if (prg_len > MTK_NOR_PRG_CNT_MAX / 8)
 			return false;
 	}
@@ -244,15 +243,19 @@  static bool mtk_nor_match_prg(const struct spi_mem_op *op)
 static void mtk_nor_adj_prg_size(struct spi_mem_op *op)
 {
 	int tx_len, tx_left, prg_left;
+	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+
+	if (op->dummy.dtr)
+		dummy_nbytes *= 2;
 
 	tx_len = op->cmd.nbytes + op->addr.nbytes;
 	if (op->data.dir == SPI_MEM_DATA_OUT) {
-		tx_len += op->dummy.nbytes;
+		tx_len += dummy_nbytes;
 		tx_left = MTK_NOR_REG_PRGDATA_MAX + 1 - tx_len;
 		if (op->data.nbytes > tx_left)
 			op->data.nbytes = tx_left;
 	} else if (op->data.dir == SPI_MEM_DATA_IN) {
-		prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - op->dummy.nbytes;
+		prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - dummy_nbytes;
 		if (prg_left > MTK_NOR_REG_SHIFT_MAX + 1)
 			prg_left = MTK_NOR_REG_SHIFT_MAX + 1;
 		if (op->data.nbytes > prg_left)
@@ -312,7 +315,7 @@  static bool mtk_nor_supports_op(struct spi_mem *mem,
 			break;
 		case SPI_MEM_DATA_OUT:
 			if ((op->addr.buswidth == 1) &&
-			    (op->dummy.nbytes == 0) &&
+			    (op->dummy.ncycles == 0) &&
 			    (op->data.buswidth == 1))
 				return true;
 			break;
@@ -515,17 +518,20 @@  static int mtk_nor_spi_mem_prg(struct mtk_nor *sp, const struct spi_mem_op *op)
 	int tx_len, prg_len;
 	int i, ret;
 	void __iomem *reg;
-	u8 bufbyte;
+	u8 bufbyte, dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+
+	if (op->dummy.dtr)
+		dummy_nbytes *= 2;
 
 	tx_len = op->cmd.nbytes + op->addr.nbytes;
 
 	// count dummy bytes only if we need to write data after it
 	if (op->data.dir == SPI_MEM_DATA_OUT)
-		tx_len += op->dummy.nbytes + op->data.nbytes;
+		tx_len += dummy_nbytes + op->data.nbytes;
 	else if (op->data.dir == SPI_MEM_DATA_IN)
 		rx_len = op->data.nbytes;
 
-	prg_len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes +
+	prg_len = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes +
 		  op->data.nbytes;
 
 	// an invalid op may reach here if the caller calls exec_op without
@@ -550,7 +556,7 @@  static int mtk_nor_spi_mem_prg(struct mtk_nor *sp, const struct spi_mem_op *op)
 	}
 
 	if (op->data.dir == SPI_MEM_DATA_OUT) {
-		for (i = 0; i < op->dummy.nbytes; i++, reg_offset--) {
+		for (i = 0; i < dummy_nbytes; i++, reg_offset--) {
 			reg = sp->base + MTK_NOR_REG_PRGDATA(reg_offset);
 			writeb(0, reg);
 		}
diff --git a/drivers/spi/spi-mtk-snfi.c b/drivers/spi/spi-mtk-snfi.c
index d66bf9762557..05d2f0a97feb 100644
--- a/drivers/spi/spi-mtk-snfi.c
+++ b/drivers/spi/spi-mtk-snfi.c
@@ -434,7 +434,10 @@  static int mtk_snand_mac_io(struct mtk_snand *snf, const struct spi_mem_op *op)
 	const u8 *tx_buf = NULL;
 	u8 *rx_buf = NULL;
 	int i, ret;
-	u8 b;
+	u8 b, dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+
+	if (op->dummy.dtr)
+		dummy_nbytes *= 2;
 
 	if (op->data.dir == SPI_MEM_DATA_IN) {
 		rx_len = op->data.nbytes;
@@ -463,7 +466,7 @@  static int mtk_snand_mac_io(struct mtk_snand *snf, const struct spi_mem_op *op)
 		}
 	}
 
-	for (i = 0; i < op->dummy.nbytes; i++, reg_offs++) {
+	for (i = 0; i < dummy_nbytes; i++, reg_offs++) {
 		if (reg_offs % 4 == 3) {
 			nfi_write32(snf, SNF_GPRAM + reg_offs - 3, val);
 			val = 0;
@@ -836,7 +839,7 @@  static int mtk_snand_read_page_cache(struct mtk_snand *snf,
 	u32 op_addr = op->addr.val;
 	// where to start copying data from bounce buffer
 	u32 rd_offset = 0;
-	u32 dummy_clk = (op->dummy.nbytes * BITS_PER_BYTE / op->dummy.buswidth);
+	u32 dummy_clk = op->dummy.ncycles;
 	u32 op_mode = 0;
 	u32 dma_len = snf->buf_len;
 	int ret = 0;
@@ -1178,8 +1181,7 @@  static bool mtk_snand_is_page_ops(const struct spi_mem_op *op)
 	// match read from page instructions
 	if (op->data.dir == SPI_MEM_DATA_IN) {
 		// check dummy cycle first
-		if (op->dummy.nbytes * BITS_PER_BYTE / op->dummy.buswidth >
-		    DATA_READ_MAX_DUMMY)
+		if (op->dummy.ncycles > DATA_READ_MAX_DUMMY)
 			return false;
 		// quad io / quad out
 		if ((op->addr.buswidth == 4 || op->addr.buswidth == 1) &&
@@ -1196,7 +1198,7 @@  static bool mtk_snand_is_page_ops(const struct spi_mem_op *op)
 			return true;
 	} else if (op->data.dir == SPI_MEM_DATA_OUT) {
 		// check dummy cycle first
-		if (op->dummy.nbytes)
+		if (op->dummy.ncycles)
 			return false;
 		// program load quad out
 		if (op->addr.buswidth == 1 && op->data.buswidth == 4)
@@ -1218,7 +1220,7 @@  static bool mtk_snand_supports_op(struct spi_mem *mem,
 	if (mtk_snand_is_page_ops(op))
 		return true;
 	return ((op->addr.nbytes == 0 || op->addr.buswidth == 1) &&
-		(op->dummy.nbytes == 0 || op->dummy.buswidth == 1) &&
+		(op->dummy.ncycles == 0 || op->dummy.buswidth == 1) &&
 		(op->data.nbytes == 0 || op->data.buswidth == 1));
 }
 
@@ -1239,7 +1241,13 @@  static int mtk_snand_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
 		if (op->data.nbytes > l)
 			op->data.nbytes = l;
 	} else {
-		size_t hl = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
+		size_t hl;
+		u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+
+		if (op->dummy.dtr)
+			dummy_nbytes *= 2;
+
+		hl = op->cmd.nbytes + op->addr.nbytes + dummy_nbytes;
 
 		if (hl >= SNF_GPRAM_SIZE)
 			return -EOPNOTSUPP;
diff --git a/drivers/spi/spi-mxic.c b/drivers/spi/spi-mxic.c
index 65be8e085ab8..d940ee0e11a5 100644
--- a/drivers/spi/spi-mxic.c
+++ b/drivers/spi/spi-mxic.c
@@ -316,14 +316,18 @@  static u32 mxic_spi_mem_prep_op_cfg(const struct spi_mem_op *op,
 	u32 cfg = OP_CMD_BYTES(op->cmd.nbytes) |
 		  OP_CMD_BUSW(fls(op->cmd.buswidth) - 1) |
 		  (op->cmd.dtr ? OP_CMD_DDR : 0);
+	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+
+	if (op->dummy.dtr)
+		dummy_nbytes *= 2;
 
 	if (op->addr.nbytes)
 		cfg |= OP_ADDR_BYTES(op->addr.nbytes) |
 		       OP_ADDR_BUSW(fls(op->addr.buswidth) - 1) |
 		       (op->addr.dtr ? OP_ADDR_DDR : 0);
 
-	if (op->dummy.nbytes)
-		cfg |= OP_DUMMY_CYC(op->dummy.nbytes);
+	if (dummy_nbytes)
+		cfg |= OP_DUMMY_CYC(dummy_nbytes);
 
 	/* Direct mapping data.nbytes field is not populated */
 	if (data_len) {
@@ -481,7 +485,7 @@  static bool mxic_spi_mem_supports_op(struct spi_mem *mem,
 	    op->dummy.buswidth > 8 || op->cmd.buswidth > 8)
 		return false;
 
-	if (op->data.nbytes && op->dummy.nbytes &&
+	if (op->data.nbytes && op->dummy.ncycles &&
 	    op->data.buswidth != op->dummy.buswidth)
 		return false;
 
@@ -512,7 +516,11 @@  static int mxic_spi_mem_exec_op(struct spi_mem *mem,
 {
 	struct mxic_spi *mxic = spi_master_get_devdata(mem->spi->master);
 	int i, ret;
-	u8 addr[8], cmd[2];
+	u8 addr[8], cmd[2], dummy_nbytes;
+
+	dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+	if (op->dummy.dtr)
+		dummy_nbytes *= 2;
 
 	ret = mxic_spi_set_freq(mxic, mem->spi->max_speed_hz);
 	if (ret)
@@ -543,7 +551,7 @@  static int mxic_spi_mem_exec_op(struct spi_mem *mem,
 	if (ret)
 		goto out;
 
-	ret = mxic_spi_data_xfer(mxic, NULL, NULL, op->dummy.nbytes);
+	ret = mxic_spi_data_xfer(mxic, NULL, NULL, dummy_nbytes);
 	if (ret)
 		goto out;
 
diff --git a/drivers/spi/spi-npcm-fiu.c b/drivers/spi/spi-npcm-fiu.c
index 49f6424e35af..17493f668459 100644
--- a/drivers/spi/spi-npcm-fiu.c
+++ b/drivers/spi/spi-npcm-fiu.c
@@ -265,6 +265,11 @@  static const struct regmap_config npcm_mtd_regmap_config = {
 static void npcm_fiu_set_drd(struct npcm_fiu_spi *fiu,
 			     const struct spi_mem_op *op)
 {
+	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+
+	if (op->dummy.dtr)
+		dummy_nbytes *= 2;
+
 	regmap_update_bits(fiu->regmap, NPCM_FIU_DRD_CFG,
 			   NPCM_FIU_DRD_CFG_ACCTYPE,
 			   ilog2(op->addr.buswidth) <<
@@ -272,8 +277,8 @@  static void npcm_fiu_set_drd(struct npcm_fiu_spi *fiu,
 	fiu->drd_op.addr.buswidth = op->addr.buswidth;
 	regmap_update_bits(fiu->regmap, NPCM_FIU_DRD_CFG,
 			   NPCM_FIU_DRD_CFG_DBW,
-			   op->dummy.nbytes << NPCM_FIU_DRD_DBW_SHIFT);
-	fiu->drd_op.dummy.nbytes = op->dummy.nbytes;
+			   dummy_nbytes << NPCM_FIU_DRD_DBW_SHIFT);
+	fiu->drd_op.dummy.ncycles = op->dummy.ncycles;
 	regmap_update_bits(fiu->regmap, NPCM_FIU_DRD_CFG,
 			   NPCM_FIU_DRD_CFG_RDCMD, op->cmd.opcode);
 	fiu->drd_op.cmd.opcode = op->cmd.opcode;
@@ -299,7 +304,7 @@  static ssize_t npcm_fiu_direct_read(struct spi_mem_dirmap_desc *desc,
 			*(buf_rx + i) = ioread8(src + i);
 	} else {
 		if (desc->info.op_tmpl.addr.buswidth != fiu->drd_op.addr.buswidth ||
-		    desc->info.op_tmpl.dummy.nbytes != fiu->drd_op.dummy.nbytes ||
+		    desc->info.op_tmpl.dummy.ncycles != fiu->drd_op.dummy.ncycles ||
 		    desc->info.op_tmpl.cmd.opcode != fiu->drd_op.cmd.opcode ||
 		    desc->info.op_tmpl.addr.nbytes != fiu->drd_op.addr.nbytes)
 			npcm_fiu_set_drd(fiu, &desc->info.op_tmpl);
@@ -341,6 +346,10 @@  static int npcm_fiu_uma_read(struct spi_mem *mem,
 	int ret;
 	u32 val;
 	u32 i;
+	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+
+	if (op->dummy.dtr)
+		dummy_nbytes *= 2;
 
 	regmap_update_bits(fiu->regmap, NPCM_FIU_UMA_CTS,
 			   NPCM_FIU_UMA_CTS_DEV_NUM,
@@ -357,7 +366,7 @@  static int npcm_fiu_uma_read(struct spi_mem *mem,
 			<< NPCM_FIU_UMA_CFG_DBPCK_SHIFT;
 		uma_cfg |= ilog2(op->data.buswidth)
 			<< NPCM_FIU_UMA_CFG_RDBPCK_SHIFT;
-		uma_cfg |= op->dummy.nbytes << NPCM_FIU_UMA_CFG_DBSIZ_SHIFT;
+		uma_cfg |= dummy_nbytes << NPCM_FIU_UMA_CFG_DBSIZ_SHIFT;
 		uma_cfg |= op->addr.nbytes << NPCM_FIU_UMA_CFG_ADDSIZ_SHIFT;
 		regmap_write(fiu->regmap, NPCM_FIU_UMA_ADDR, addr);
 	} else {
diff --git a/drivers/spi/spi-nxp-fspi.c b/drivers/spi/spi-nxp-fspi.c
index 2b0301fc971c..ccec9b726283 100644
--- a/drivers/spi/spi-nxp-fspi.c
+++ b/drivers/spi/spi-nxp-fspi.c
@@ -444,7 +444,7 @@  static bool nxp_fspi_supports_op(struct spi_mem *mem,
 	if (op->addr.nbytes)
 		ret |= nxp_fspi_check_buswidth(f, op->addr.buswidth);
 
-	if (op->dummy.nbytes)
+	if (op->dummy.ncycles)
 		ret |= nxp_fspi_check_buswidth(f, op->dummy.buswidth);
 
 	if (op->data.nbytes)
@@ -468,8 +468,7 @@  static bool nxp_fspi_supports_op(struct spi_mem *mem,
 		return false;
 
 	/* Max 64 dummy clock cycles supported */
-	if (op->dummy.buswidth &&
-	    (op->dummy.nbytes * 8 / op->dummy.buswidth > 64))
+	if (op->dummy.ncycles > 64)
 		return false;
 
 	/* Max data length, check controller limits and alignment */
@@ -543,15 +542,14 @@  static void nxp_fspi_prepare_lut(struct nxp_fspi *f,
 	}
 
 	/* dummy bytes, if needed */
-	if (op->dummy.nbytes) {
+	if (op->dummy.ncycles) {
 		lutval[lutidx / 2] |= LUT_DEF(lutidx, LUT_DUMMY,
 		/*
 		 * Due to FlexSPI controller limitation number of PAD for dummy
 		 * buswidth needs to be programmed as equal to data buswidth.
 		 */
 					      LUT_PAD(op->data.buswidth),
-					      op->dummy.nbytes * 8 /
-					      op->dummy.buswidth);
+					      op->dummy.ncycles);
 		lutidx++;
 	}
 
diff --git a/drivers/spi/spi-rockchip-sfc.c b/drivers/spi/spi-rockchip-sfc.c
index bd87d3c92dd3..82f9e61b9036 100644
--- a/drivers/spi/spi-rockchip-sfc.c
+++ b/drivers/spi/spi-rockchip-sfc.c
@@ -282,16 +282,21 @@  static int rockchip_sfc_wait_rxfifo_ready(struct rockchip_sfc *sfc, u32 timeout_
 
 static void rockchip_sfc_adjust_op_work(struct spi_mem_op *op)
 {
-	if (unlikely(op->dummy.nbytes && !op->addr.nbytes)) {
+	if (unlikely(op->dummy.ncycles && !op->addr.nbytes)) {
+		u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+
+		if (op->dummy.dtr)
+			dummy_nbytes *= 2;
+
 		/*
 		 * SFC not support output DUMMY cycles right after CMD cycles, so
 		 * treat it as ADDR cycles.
 		 */
-		op->addr.nbytes = op->dummy.nbytes;
+		op->addr.nbytes = dummy_nbytes;
 		op->addr.buswidth = op->dummy.buswidth;
 		op->addr.val = 0xFFFFFFFFF;
 
-		op->dummy.nbytes = 0;
+		op->dummy.ncycles = 0;
 	}
 }
 
@@ -301,6 +306,10 @@  static int rockchip_sfc_xfer_setup(struct rockchip_sfc *sfc,
 				   u32 len)
 {
 	u32 ctrl = 0, cmd = 0;
+	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+
+	if (op->dummy.dtr)
+		dummy_nbytes *= 2;
 
 	/* set CMD */
 	cmd = op->cmd.opcode;
@@ -321,13 +330,13 @@  static int rockchip_sfc_xfer_setup(struct rockchip_sfc *sfc,
 	}
 
 	/* set DUMMY */
-	if (op->dummy.nbytes) {
+	if (dummy_nbytes) {
 		if (op->dummy.buswidth == 4)
-			cmd |= op->dummy.nbytes * 2 << SFC_CMD_DUMMY_SHIFT;
+			cmd |= dummy_nbytes * 2 << SFC_CMD_DUMMY_SHIFT;
 		else if (op->dummy.buswidth == 2)
-			cmd |= op->dummy.nbytes * 4 << SFC_CMD_DUMMY_SHIFT;
+			cmd |= dummy_nbytes * 4 << SFC_CMD_DUMMY_SHIFT;
 		else
-			cmd |= op->dummy.nbytes * 8 << SFC_CMD_DUMMY_SHIFT;
+			cmd |= dummy_nbytes * 8 << SFC_CMD_DUMMY_SHIFT;
 	}
 
 	/* set DATA */
@@ -348,9 +357,9 @@  static int rockchip_sfc_xfer_setup(struct rockchip_sfc *sfc,
 	ctrl |= SFC_CTRL_PHASE_SEL_NEGETIVE;
 	cmd |= mem->spi->chip_select << SFC_CMD_CS_SHIFT;
 
-	dev_dbg(sfc->dev, "sfc addr.nbytes=%x(x%d) dummy.nbytes=%x(x%d)\n",
+	dev_dbg(sfc->dev, "sfc addr.nbytes=%x(x%d) dummy.ncycles=%x(x%d)\n",
 		op->addr.nbytes, op->addr.buswidth,
-		op->dummy.nbytes, op->dummy.buswidth);
+		op->dummy.ncycles, op->dummy.buswidth);
 	dev_dbg(sfc->dev, "sfc ctrl=%x cmd=%x addr=%llx len=%x\n",
 		ctrl, cmd, op->addr.val, len);
 
diff --git a/drivers/spi/spi-rpc-if.c b/drivers/spi/spi-rpc-if.c
index 24ec1c83f379..fb317a80bef8 100644
--- a/drivers/spi/spi-rpc-if.c
+++ b/drivers/spi/spi-rpc-if.c
@@ -32,10 +32,9 @@  static void rpcif_spi_mem_prepare(struct spi_device *spi_dev,
 		rpc_op.addr.val = spi_op->addr.val;
 	}
 
-	if (spi_op->dummy.nbytes) {
+	if (spi_op->dummy.ncycles) {
 		rpc_op.dummy.buswidth = spi_op->dummy.buswidth;
-		rpc_op.dummy.ncycles  = spi_op->dummy.nbytes * 8 /
-					spi_op->dummy.buswidth;
+		rpc_op.dummy.ncycles  = spi_op->dummy.ncycles;
 	}
 
 	if (spi_op->data.nbytes || (offs && len)) {
diff --git a/drivers/spi/spi-stm32-qspi.c b/drivers/spi/spi-stm32-qspi.c
index f3fe92300639..9072345eddde 100644
--- a/drivers/spi/spi-stm32-qspi.c
+++ b/drivers/spi/spi-stm32-qspi.c
@@ -388,9 +388,8 @@  static int stm32_qspi_send(struct spi_mem *mem, const struct spi_mem_op *op)
 		ccr |= FIELD_PREP(CCR_ADSIZE_MASK, op->addr.nbytes - 1);
 	}
 
-	if (op->dummy.nbytes)
-		ccr |= FIELD_PREP(CCR_DCYC_MASK,
-				  op->dummy.nbytes * 8 / op->dummy.buswidth);
+	if (op->dummy.ncycles)
+		ccr |= FIELD_PREP(CCR_DCYC_MASK, op->dummy.ncycles);
 
 	if (op->data.nbytes) {
 		ccr |= FIELD_PREP(CCR_DMODE_MASK,
diff --git a/drivers/spi/spi-ti-qspi.c b/drivers/spi/spi-ti-qspi.c
index 60086869bcae..377bc119344f 100644
--- a/drivers/spi/spi-ti-qspi.c
+++ b/drivers/spi/spi-ti-qspi.c
@@ -579,6 +579,10 @@  static int ti_qspi_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
 {
 	struct ti_qspi *qspi = spi_controller_get_devdata(mem->spi->master);
 	size_t max_len;
+	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+
+	if (op->dummy.dtr)
+		dummy_nbytes *= 2;
 
 	if (op->data.dir == SPI_MEM_DATA_IN) {
 		if (op->addr.val < qspi->mmap_size) {
@@ -595,7 +599,7 @@  static int ti_qspi_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
 			 * Adjust size to comply with the QSPI max frame length.
 			 */
 			max_len = QSPI_FRAME;
-			max_len -= 1 + op->addr.nbytes + op->dummy.nbytes;
+			max_len -= 1 + op->addr.nbytes + dummy_nbytes;
 			op->data.nbytes = min((size_t) op->data.nbytes,
 					      max_len);
 		}
@@ -610,6 +614,10 @@  static int ti_qspi_exec_mem_op(struct spi_mem *mem,
 	struct ti_qspi *qspi = spi_master_get_devdata(mem->spi->master);
 	u32 from = 0;
 	int ret = 0;
+	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+
+	if (op->dummy.dtr)
+		dummy_nbytes *= 2;
 
 	/* Only optimize read path. */
 	if (!op->data.nbytes || op->data.dir != SPI_MEM_DATA_IN ||
@@ -628,7 +636,7 @@  static int ti_qspi_exec_mem_op(struct spi_mem *mem,
 		ti_qspi_enable_memory_map(mem->spi);
 	}
 	ti_qspi_setup_mmap_read(mem->spi, op->cmd.opcode, op->data.buswidth,
-				op->addr.nbytes, op->dummy.nbytes);
+				op->addr.nbytes, dummy_nbytes);
 
 	if (qspi->rx_chan) {
 		struct sg_table sgt;
diff --git a/drivers/spi/spi-zynq-qspi.c b/drivers/spi/spi-zynq-qspi.c
index 78f31b61a2aa..84b7db85548c 100644
--- a/drivers/spi/spi-zynq-qspi.c
+++ b/drivers/spi/spi-zynq-qspi.c
@@ -527,7 +527,10 @@  static int zynq_qspi_exec_mem_op(struct spi_mem *mem,
 {
 	struct zynq_qspi *xqspi = spi_controller_get_devdata(mem->spi->master);
 	int err = 0, i;
-	u8 *tmpbuf;
+	u8 *tmpbuf, dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+
+	if (op->dummy.dtr)
+		dummy_nbytes *= 2;
 
 	dev_dbg(xqspi->dev, "cmd:%#x mode:%d.%d.%d.%d\n",
 		op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
@@ -568,17 +571,17 @@  static int zynq_qspi_exec_mem_op(struct spi_mem *mem,
 			err = -ETIMEDOUT;
 	}
 
-	if (op->dummy.nbytes) {
-		tmpbuf = kzalloc(op->dummy.nbytes, GFP_KERNEL);
+	if (dummy_nbytes) {
+		tmpbuf = kzalloc(dummy_nbytes, GFP_KERNEL);
 		if (!tmpbuf)
 			return -ENOMEM;
 
-		memset(tmpbuf, 0xff, op->dummy.nbytes);
+		memset(tmpbuf, 0xff, dummy_nbytes);
 		reinit_completion(&xqspi->data_completion);
 		xqspi->txbuf = tmpbuf;
 		xqspi->rxbuf = NULL;
-		xqspi->tx_bytes = op->dummy.nbytes;
-		xqspi->rx_bytes = op->dummy.nbytes;
+		xqspi->tx_bytes = dummy_nbytes;
+		xqspi->rx_bytes = dummy_nbytes;
 		zynq_qspi_write_op(xqspi, ZYNQ_QSPI_FIFO_DEPTH, true);
 		zynq_qspi_write(xqspi, ZYNQ_QSPI_IEN_OFFSET,
 				ZYNQ_QSPI_IXR_RXTX_MASK);
diff --git a/drivers/spi/spi-zynqmp-gqspi.c b/drivers/spi/spi-zynqmp-gqspi.c
index c760aac070e5..b41abadef9a6 100644
--- a/drivers/spi/spi-zynqmp-gqspi.c
+++ b/drivers/spi/spi-zynqmp-gqspi.c
@@ -948,6 +948,10 @@  static int zynqmp_qspi_exec_op(struct spi_mem *mem,
 	u32 genfifoentry = 0;
 	u16 opcode = op->cmd.opcode;
 	u64 opaddr;
+	u8 dummy_nbytes = (op->dummy.ncycles * op->dummy.buswidth) / 8;
+
+	if (op->dummy.dtr)
+		dummy_nbytes *= 2;
 
 	dev_dbg(xqspi->dev, "cmd:%#x mode:%d.%d.%d.%d\n",
 		op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
@@ -1006,14 +1010,14 @@  static int zynqmp_qspi_exec_op(struct spi_mem *mem,
 		}
 	}
 
-	if (op->dummy.nbytes) {
+	if (dummy_nbytes) {
 		xqspi->txbuf = NULL;
 		xqspi->rxbuf = NULL;
 		/*
 		 * xqspi->bytes_to_transfer here represents the dummy circles
 		 * which need to be sent.
 		 */
-		xqspi->bytes_to_transfer = op->dummy.nbytes * 8 / op->dummy.buswidth;
+		xqspi->bytes_to_transfer = dummy_nbytes;
 		xqspi->bytes_to_receive = 0;
 		/*
 		 * Using op->data.buswidth instead of op->dummy.buswidth here because
diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h
index 2ba044d0d5e5..5fd45800af03 100644
--- a/include/linux/spi/spi-mem.h
+++ b/include/linux/spi/spi-mem.h
@@ -29,9 +29,9 @@ 
 
 #define SPI_MEM_OP_NO_ADDR	{ }
 
-#define SPI_MEM_OP_DUMMY(__nbytes, __buswidth)			\
+#define SPI_MEM_OP_DUMMY(__ncycles, __buswidth)		\
 	{							\
-		.nbytes = __nbytes,				\
+		.ncycles = __ncycles,				\
 		.buswidth = __buswidth,				\
 	}
 
@@ -83,8 +83,8 @@  enum spi_mem_data_dir {
  *	      Note that only @addr.nbytes are taken into account in this
  *	      address value, so users should make sure the value fits in the
  *	      assigned number of bytes.
- * @dummy.nbytes: number of dummy bytes to send after an opcode or address. Can
- *		  be zero if the operation does not require dummy bytes
+ * @dummy.ncycles: number of dummy cycles after an opcode or address. Can
+ *		   be zero if the operation does not require dummy cycles
  * @dummy.buswidth: number of IO lanes used to transmit the dummy bytes
  * @dummy.dtr: whether the dummy bytes should be sent in DTR mode or not
  * @data.buswidth: number of IO lanes used to send/receive the data
@@ -112,7 +112,7 @@  struct spi_mem_op {
 	} addr;
 
 	struct {
-		u8 nbytes;
+		u8 ncycles;
 		u8 buswidth;
 		u8 dtr : 1;
 	} dummy;