diff mbox

[v6,8/8] spi: imx: add support for all SPI word width for DMA

Message ID 1449557030-27525-9-git-send-email-anton.bondarenko.sama@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Anton Bondarenko Dec. 8, 2015, 6:43 a.m. UTC 
DMA transfer for SPI was limited to up to 8 bits word size until now.
Sync in SPI burst size and DMA bus width is necessary to correctly
support 16 and 32 BPW.

Signed-off-by: Anton Bondarenko <anton.bondarenko.sama@gmail.com>
---
 drivers/spi/spi-imx.c | 121 +++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 95 insertions(+), 26 deletions(-)

Comments

Robin Gong Dec. 15, 2015, 9:41 a.m. UTC | #1 
On Tue, Dec 08, 2015 at 07:43:50AM +0100, Anton Bondarenko wrote:
> DMA transfer for SPI was limited to up to 8 bits word size until now.
> Sync in SPI burst size and DMA bus width is necessary to correctly
> support 16 and 32 BPW.
> 
> Signed-off-by: Anton Bondarenko <anton.bondarenko.sama@gmail.com>
> ---
>  drivers/spi/spi-imx.c | 121 +++++++++++++++++++++++++++++++++++++++-----------
>  1 file changed, 95 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
> index d74d809..750001c 100644
> --- a/drivers/spi/spi-imx.c
> +++ b/drivers/spi/spi-imx.c
> @@ -88,11 +88,15 @@ struct spi_imx_data {
>  
>  	struct completion xfer_done;
>  	void __iomem *base;
> +	unsigned long base_phys;
> +
>  	struct clk *clk_per;
>  	struct clk *clk_ipg;
>  	unsigned long spi_clk;
>  	unsigned int spi_bus_clk;
>  
> +	unsigned int bytes_per_word;
> +
>  	unsigned int count;
>  	void (*tx)(struct spi_imx_data *);
>  	void (*rx)(struct spi_imx_data *);
> @@ -199,13 +203,32 @@ static unsigned int spi_imx_clkdiv_2(unsigned int fin,
>  	return 7;
>  }
>  
> +static int spi_imx_get_bytes_per_word(const int bpw)
> +{
> +	return DIV_ROUND_UP(bpw, BITS_PER_BYTE);
> +}
> +
>  static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi,
>  			 struct spi_transfer *transfer)
>  {
>  	struct spi_imx_data *spi_imx = spi_master_get_devdata(master);
> +	unsigned int bpw = transfer->bits_per_word;
> +
> +	if (!bpw)
> +		bpw = spi->bits_per_word;
>  
> -	if (spi_imx->dma_is_inited && transfer->len >= spi_imx->wml &&
> -	    (transfer->len % spi_imx->wml) == 0)
> +	bpw = spi_imx_get_bytes_per_word(bpw);
> +
> +	/*
> +	 * We need to use SPI word size in calculation to decide
> +	 * if we want to go with DMA or PIO mode. Just a short example:
> +	 * We need to transfer 24 SPI words with BPW == 32. This will take
> +	 * 24 PIO writes to FIFO (and same for reads). But transfer->len will
> +	 * be 24*4=96 bytes. WML is 32 SPI words. The decision will be incorrect
> +	 * if we do not take into account SPI bits per word.
> +	 */
> +	if (spi_imx->dma_is_inited && transfer->len >= (spi_imx->wml * bpw) &&
> +	    (transfer->len % (spi_imx->wml * bpw)) == 0)
>  		return true;
>  	return false;
>  }
> @@ -785,11 +808,60 @@ static irqreturn_t spi_imx_isr(int irq, void *dev_id)
>  	return IRQ_HANDLED;
>  }
>  
> +static int spi_imx_sdma_configure(struct spi_master *master)
> +{
> +	int ret;
> +	enum dma_slave_buswidth dsb_default = DMA_SLAVE_BUSWIDTH_1_BYTE;
> +	struct dma_slave_config slave_config = {};
> +	struct spi_imx_data *spi_imx = spi_master_get_devdata(master);
> +
> +	switch (spi_imx->bytes_per_word) {
> +	case 4:
> +		dsb_default = DMA_SLAVE_BUSWIDTH_4_BYTES;
> +		break;
> +	case 2:
> +		dsb_default = DMA_SLAVE_BUSWIDTH_2_BYTES;
> +		break;
> +	case 1:
> +		dsb_default = DMA_SLAVE_BUSWIDTH_1_BYTE;
> +		break;
> +	default:
> +		pr_err("Not supported word size %d\n", spi_imx->bytes_per_word);
> +		ret = -EINVAL;
> +		goto err;
> +	}
> +
> +	slave_config.direction = DMA_MEM_TO_DEV;
> +	slave_config.dst_addr = spi_imx->base_phys + MXC_CSPITXDATA;
> +	slave_config.dst_addr_width = dsb_default;
> +	slave_config.dst_maxburst = spi_imx->wml;
> +	ret = dmaengine_slave_config(master->dma_tx, &slave_config);
> +	if (ret) {
> +		pr_err("error in TX dma configuration.\n");
> +		goto err;
> +	}
> +
> +	memset(&slave_config, 0, sizeof(slave_config));
> +
> +	slave_config.direction = DMA_DEV_TO_MEM;
> +	slave_config.src_addr = spi_imx->base_phys + MXC_CSPIRXDATA;
> +	slave_config.src_addr_width = dsb_default;
> +	slave_config.src_maxburst = spi_imx->wml;
> +	ret = dmaengine_slave_config(master->dma_rx, &slave_config);
> +	if (ret)
> +		pr_err("error in RX dma configuration.\n");
> +
> +err:
> +	return ret;
> +}
> +
>  static int spi_imx_setupxfer(struct spi_device *spi,
>  				 struct spi_transfer *t)
>  {
>  	struct spi_imx_data *spi_imx = spi_master_get_devdata(spi->master);
>  	struct spi_imx_config config;
> +	unsigned int new_bytes_per_word;
> +	int ret = 0;
>  
>  	config.bpw = t ? t->bits_per_word : spi->bits_per_word;
>  	config.speed_hz  = t ? t->speed_hz : spi->max_speed_hz;
> @@ -813,9 +885,19 @@ static int spi_imx_setupxfer(struct spi_device *spi,
>  		spi_imx->tx = spi_imx_buf_tx_u32;
>  	}
>  
> -	spi_imx->devtype_data->config(spi_imx, &config);
> +	new_bytes_per_word = spi_imx_get_bytes_per_word(config.bpw);
> +	if (spi_imx->dma_is_inited &&
> +	    spi_imx->bytes_per_word != new_bytes_per_word) {
Configure dma even in PIO mode for some minimal data transfer case?It's better
to check can_dma here.
> +		spi_imx->bytes_per_word = new_bytes_per_word;
> +		ret = spi_imx_sdma_configure(spi->master);
> +		if (ret != 0)
> +			pr_err("Can't configure SDMA, error %d\n", ret);
> +	}
>  
> -	return 0;
> +	if (!ret)
> +		ret = spi_imx->devtype_data->config(spi_imx, &config);
> +
> +	return ret;
>  }
>  
>  static void spi_imx_sdma_exit(struct spi_imx_data *spi_imx)
> @@ -839,7 +921,6 @@ static int spi_imx_sdma_init(struct device *dev, struct spi_imx_data *spi_imx,
>  			     struct spi_master *master,
>  			     const struct resource *res)
>  {
> -	struct dma_slave_config slave_config = {};
>  	int ret;
>  
>  	/* use pio mode for i.mx6dl chip TKT238285 */
> @@ -857,16 +938,6 @@ static int spi_imx_sdma_init(struct device *dev, struct spi_imx_data *spi_imx,
>  		goto err;
>  	}
>  
> -	slave_config.direction = DMA_MEM_TO_DEV;
> -	slave_config.dst_addr = res->start + MXC_CSPITXDATA;
> -	slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
> -	slave_config.dst_maxburst = spi_imx->wml;
> -	ret = dmaengine_slave_config(master->dma_tx, &slave_config);
> -	if (ret) {
> -		dev_err(dev, "error in TX dma configuration.\n");
> -		goto err;
> -	}
> -
>  	/* Prepare for RX : */
>  	master->dma_rx = dma_request_slave_channel_reason(dev, "rx");
>  	if (IS_ERR(master->dma_rx)) {
> @@ -876,22 +947,20 @@ static int spi_imx_sdma_init(struct device *dev, struct spi_imx_data *spi_imx,
>  		goto err;
>  	}
>  
> -	slave_config.direction = DMA_DEV_TO_MEM;
> -	slave_config.src_addr = res->start + MXC_CSPIRXDATA;
> -	slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
> -	slave_config.src_maxburst = spi_imx->wml;
> -	ret = dmaengine_slave_config(master->dma_rx, &slave_config);
> -	if (ret) {
> -		dev_err(dev, "error in RX dma configuration.\n");
> -		goto err;
> -	}
> -
>  	init_completion(&spi_imx->dma_rx_completion);
>  	init_completion(&spi_imx->dma_tx_completion);
>  	master->can_dma = spi_imx_can_dma;
>  	master->max_dma_len = MAX_SDMA_BD_BYTES;
>  	spi_imx->bitbang.master->flags = SPI_MASTER_MUST_RX |
>  					 SPI_MASTER_MUST_TX;
> +	spi_imx->bytes_per_word = 1;
> +	spi_imx->base_phys = res->start;
> +	ret = spi_imx_sdma_configure(master);
> +	if (ret) {
> +		dev_info(dev, "cannot get setup DMA.\n");
> +		goto err;
> +	}
> +
>  	spi_imx->dma_is_inited = 1;
>  
>  	return 0;
> @@ -993,7 +1062,7 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
>  		dmaengine_terminate_all(master->dma_rx);
>  	} else {
>  		transfer_timeout = spi_imx_calculate_timeout(spi_imx,
> -							     spi_imx->wml);
> +					spi_imx->bytes_per_word * spi_imx->wml);
>  		timeout = wait_for_completion_timeout(
>  				&spi_imx->dma_rx_completion, transfer_timeout);
>  		if (!timeout) {
> -- 
> 2.6.3
> 
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diff mbox

Patch

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index d74d809..750001c 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -88,11 +88,15 @@  struct spi_imx_data {
 
 	struct completion xfer_done;
 	void __iomem *base;
+	unsigned long base_phys;
+
 	struct clk *clk_per;
 	struct clk *clk_ipg;
 	unsigned long spi_clk;
 	unsigned int spi_bus_clk;
 
+	unsigned int bytes_per_word;
+
 	unsigned int count;
 	void (*tx)(struct spi_imx_data *);
 	void (*rx)(struct spi_imx_data *);
@@ -199,13 +203,32 @@  static unsigned int spi_imx_clkdiv_2(unsigned int fin,
 	return 7;
 }
 
+static int spi_imx_get_bytes_per_word(const int bpw)
+{
+	return DIV_ROUND_UP(bpw, BITS_PER_BYTE);
+}
+
 static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi,
 			 struct spi_transfer *transfer)
 {
 	struct spi_imx_data *spi_imx = spi_master_get_devdata(master);
+	unsigned int bpw = transfer->bits_per_word;
+
+	if (!bpw)
+		bpw = spi->bits_per_word;
 
-	if (spi_imx->dma_is_inited && transfer->len >= spi_imx->wml &&
-	    (transfer->len % spi_imx->wml) == 0)
+	bpw = spi_imx_get_bytes_per_word(bpw);
+
+	/*
+	 * We need to use SPI word size in calculation to decide
+	 * if we want to go with DMA or PIO mode. Just a short example:
+	 * We need to transfer 24 SPI words with BPW == 32. This will take
+	 * 24 PIO writes to FIFO (and same for reads). But transfer->len will
+	 * be 24*4=96 bytes. WML is 32 SPI words. The decision will be incorrect
+	 * if we do not take into account SPI bits per word.
+	 */
+	if (spi_imx->dma_is_inited && transfer->len >= (spi_imx->wml * bpw) &&
+	    (transfer->len % (spi_imx->wml * bpw)) == 0)
 		return true;
 	return false;
 }
@@ -785,11 +808,60 @@  static irqreturn_t spi_imx_isr(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static int spi_imx_sdma_configure(struct spi_master *master)
+{
+	int ret;
+	enum dma_slave_buswidth dsb_default = DMA_SLAVE_BUSWIDTH_1_BYTE;
+	struct dma_slave_config slave_config = {};
+	struct spi_imx_data *spi_imx = spi_master_get_devdata(master);
+
+	switch (spi_imx->bytes_per_word) {
+	case 4:
+		dsb_default = DMA_SLAVE_BUSWIDTH_4_BYTES;
+		break;
+	case 2:
+		dsb_default = DMA_SLAVE_BUSWIDTH_2_BYTES;
+		break;
+	case 1:
+		dsb_default = DMA_SLAVE_BUSWIDTH_1_BYTE;
+		break;
+	default:
+		pr_err("Not supported word size %d\n", spi_imx->bytes_per_word);
+		ret = -EINVAL;
+		goto err;
+	}
+
+	slave_config.direction = DMA_MEM_TO_DEV;
+	slave_config.dst_addr = spi_imx->base_phys + MXC_CSPITXDATA;
+	slave_config.dst_addr_width = dsb_default;
+	slave_config.dst_maxburst = spi_imx->wml;
+	ret = dmaengine_slave_config(master->dma_tx, &slave_config);
+	if (ret) {
+		pr_err("error in TX dma configuration.\n");
+		goto err;
+	}
+
+	memset(&slave_config, 0, sizeof(slave_config));
+
+	slave_config.direction = DMA_DEV_TO_MEM;
+	slave_config.src_addr = spi_imx->base_phys + MXC_CSPIRXDATA;
+	slave_config.src_addr_width = dsb_default;
+	slave_config.src_maxburst = spi_imx->wml;
+	ret = dmaengine_slave_config(master->dma_rx, &slave_config);
+	if (ret)
+		pr_err("error in RX dma configuration.\n");
+
+err:
+	return ret;
+}
+
 static int spi_imx_setupxfer(struct spi_device *spi,
 				 struct spi_transfer *t)
 {
 	struct spi_imx_data *spi_imx = spi_master_get_devdata(spi->master);
 	struct spi_imx_config config;
+	unsigned int new_bytes_per_word;
+	int ret = 0;
 
 	config.bpw = t ? t->bits_per_word : spi->bits_per_word;
 	config.speed_hz  = t ? t->speed_hz : spi->max_speed_hz;
@@ -813,9 +885,19 @@  static int spi_imx_setupxfer(struct spi_device *spi,
 		spi_imx->tx = spi_imx_buf_tx_u32;
 	}
 
-	spi_imx->devtype_data->config(spi_imx, &config);
+	new_bytes_per_word = spi_imx_get_bytes_per_word(config.bpw);
+	if (spi_imx->dma_is_inited &&
+	    spi_imx->bytes_per_word != new_bytes_per_word) {
+		spi_imx->bytes_per_word = new_bytes_per_word;
+		ret = spi_imx_sdma_configure(spi->master);
+		if (ret != 0)
+			pr_err("Can't configure SDMA, error %d\n", ret);
+	}
 
-	return 0;
+	if (!ret)
+		ret = spi_imx->devtype_data->config(spi_imx, &config);
+
+	return ret;
 }
 
 static void spi_imx_sdma_exit(struct spi_imx_data *spi_imx)
@@ -839,7 +921,6 @@  static int spi_imx_sdma_init(struct device *dev, struct spi_imx_data *spi_imx,
 			     struct spi_master *master,
 			     const struct resource *res)
 {
-	struct dma_slave_config slave_config = {};
 	int ret;
 
 	/* use pio mode for i.mx6dl chip TKT238285 */
@@ -857,16 +938,6 @@  static int spi_imx_sdma_init(struct device *dev, struct spi_imx_data *spi_imx,
 		goto err;
 	}
 
-	slave_config.direction = DMA_MEM_TO_DEV;
-	slave_config.dst_addr = res->start + MXC_CSPITXDATA;
-	slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
-	slave_config.dst_maxburst = spi_imx->wml;
-	ret = dmaengine_slave_config(master->dma_tx, &slave_config);
-	if (ret) {
-		dev_err(dev, "error in TX dma configuration.\n");
-		goto err;
-	}
-
 	/* Prepare for RX : */
 	master->dma_rx = dma_request_slave_channel_reason(dev, "rx");
 	if (IS_ERR(master->dma_rx)) {
@@ -876,22 +947,20 @@  static int spi_imx_sdma_init(struct device *dev, struct spi_imx_data *spi_imx,
 		goto err;
 	}
 
-	slave_config.direction = DMA_DEV_TO_MEM;
-	slave_config.src_addr = res->start + MXC_CSPIRXDATA;
-	slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
-	slave_config.src_maxburst = spi_imx->wml;
-	ret = dmaengine_slave_config(master->dma_rx, &slave_config);
-	if (ret) {
-		dev_err(dev, "error in RX dma configuration.\n");
-		goto err;
-	}
-
 	init_completion(&spi_imx->dma_rx_completion);
 	init_completion(&spi_imx->dma_tx_completion);
 	master->can_dma = spi_imx_can_dma;
 	master->max_dma_len = MAX_SDMA_BD_BYTES;
 	spi_imx->bitbang.master->flags = SPI_MASTER_MUST_RX |
 					 SPI_MASTER_MUST_TX;
+	spi_imx->bytes_per_word = 1;
+	spi_imx->base_phys = res->start;
+	ret = spi_imx_sdma_configure(master);
+	if (ret) {
+		dev_info(dev, "cannot get setup DMA.\n");
+		goto err;
+	}
+
 	spi_imx->dma_is_inited = 1;
 
 	return 0;
@@ -993,7 +1062,7 @@  static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
 		dmaengine_terminate_all(master->dma_rx);
 	} else {
 		transfer_timeout = spi_imx_calculate_timeout(spi_imx,
-							     spi_imx->wml);
+					spi_imx->bytes_per_word * spi_imx->wml);
 		timeout = wait_for_completion_timeout(
 				&spi_imx->dma_rx_completion, transfer_timeout);
 		if (!timeout) {