| Message ID | 20221223123854.8023-1-i.bornyakov@metrotek.ru (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | fpga: microchip-spi: move SPI I/O buffers out of stack | expand |
On 2022-12-23 at 15:38:54 +0300, Ivan Bornyakov wrote: > As spi-summary doc says: > > I/O buffers use the usual Linux rules, and must be DMA-safe. > > You'd normally allocate them from the heap or free page pool. > > Don't use the stack, or anything that's declared "static". > > Replace spi_write() with spi_write_then_read(), which is dma-safe for > on-stack buffers. Use allocated buffers for transfers used in > spi_sync_transfer(). > > Although everything works OK with stack-located I/O buffers, better > follow the doc to be safe. > > While at it, replace busy loop in mpf_poll_status() routine with > read_poll_timeout() macro. Original busy loop is not too reliable, as it > takes different times on different systems. Yes, I see there are several intents in this patch, spi dma safe fix, busy loop change, coding style ... Could you help split them, one change for each patch? > > Fixes: 5f8d4a900830 ("fpga: microchip-spi: add Microchip MPF FPGA manager") > Signed-off-by: Ivan Bornyakov <i.bornyakov@metrotek.ru> > --- > drivers/fpga/microchip-spi.c | 145 +++++++++++++++++++---------------- > 1 file changed, 80 insertions(+), 65 deletions(-) > > diff --git a/drivers/fpga/microchip-spi.c b/drivers/fpga/microchip-spi.c > index 7436976ea904..dfb4e071db86 100644 > --- a/drivers/fpga/microchip-spi.c > +++ b/drivers/fpga/microchip-spi.c > @@ -6,6 +6,7 @@ > #include <asm/unaligned.h> > #include <linux/delay.h> > #include <linux/fpga/fpga-mgr.h> > +#include <linux/iopoll.h> > #include <linux/module.h> > #include <linux/of_device.h> > #include <linux/spi/spi.h> > @@ -33,7 +34,6 @@ > > #define MPF_BITS_PER_COMPONENT_SIZE 22 > > -#define MPF_STATUS_POLL_RETRIES 10000 > #define MPF_STATUS_BUSY BIT(0) > #define MPF_STATUS_READY BIT(1) > #define MPF_STATUS_SPI_VIOLATION BIT(2) > @@ -42,46 +42,55 @@ > struct mpf_priv { > struct spi_device *spi; > bool program_mode; > + u8 *tx; > + u8 *rx; u8 tx __aligned(ARCH_KMALLOC_MINALIGN); u8 rx; Is that OK? > }; > > -static int mpf_read_status(struct spi_device *spi) > +static int mpf_read_status(struct mpf_priv *priv) > { > - u8 status = 0, status_command = MPF_SPI_READ_STATUS; > - struct spi_transfer xfers[2] = { 0 }; > - int ret; > - > /* > * HW status is returned on MISO in the first byte after CS went > * active. However, first reading can be inadequate, so we submit > * two identical SPI transfers and use result of the later one. > */ > - xfers[0].tx_buf = &status_command; > - xfers[1].tx_buf = &status_command; > - xfers[0].rx_buf = &status; > - xfers[1].rx_buf = &status; > - xfers[0].len = 1; > - xfers[1].len = 1; > - xfers[0].cs_change = 1; > + struct spi_transfer xfers[2] = { > + { > + .tx_buf = priv->tx, > + .rx_buf = priv->rx, > + .len = 1, > + .cs_change = 1, > + }, { > + .tx_buf = priv->tx, > + .rx_buf = priv->rx, > + .len = 1, > + }, > + }; > + u8 status; > + int ret; > > - ret = spi_sync_transfer(spi, xfers, 2); > + *priv->tx = MPF_SPI_READ_STATUS; > + > + ret = spi_sync_transfer(priv->spi, xfers, 2); > + if (ret) > + return ret; > + > + status = *priv->rx; > > if ((status & MPF_STATUS_SPI_VIOLATION) || > (status & MPF_STATUS_SPI_ERROR)) > - ret = -EIO; > + return -EIO; > > - return ret ? : status; > + return status; > } > > static enum fpga_mgr_states mpf_ops_state(struct fpga_manager *mgr) > { > struct mpf_priv *priv = mgr->priv; > - struct spi_device *spi; > bool program_mode; > int status; > > - spi = priv->spi; > program_mode = priv->program_mode; > - status = mpf_read_status(spi); > + status = mpf_read_status(priv); > > if (!program_mode && !status) > return FPGA_MGR_STATE_OPERATING; > @@ -186,51 +195,47 @@ static int mpf_ops_parse_header(struct fpga_manager *mgr, > } > > /* Poll HW status until busy bit is cleared and mask bits are set. */ > -static int mpf_poll_status(struct spi_device *spi, u8 mask) > +static int mpf_poll_status(struct mpf_priv *priv, u8 mask) > { > - int status, retries = MPF_STATUS_POLL_RETRIES; > - > - while (retries--) { > - status = mpf_read_status(spi); > - if (status < 0) > - return status; > + int ret, status; > > - if (status & MPF_STATUS_BUSY) > - continue; > - > - if (!mask || (status & mask)) > - return status; > - } > + ret = read_poll_timeout(mpf_read_status, status, > + (status < 0) || > + (!(status & MPF_STATUS_BUSY) && > + (!mask || (status & mask))), > + 0, 2 * USEC_PER_SEC, false, priv); use a MACRO for timeout value. Thanks, Yilun > + if (ret < 0) > + return ret; > > - return -EBUSY; > + return status; > } > > -static int mpf_spi_write(struct spi_device *spi, const void *buf, size_t buf_size) > +static int mpf_spi_write(struct mpf_priv *priv, const void *buf, size_t buf_size) > { > - int status = mpf_poll_status(spi, 0); > + int status = mpf_poll_status(priv, 0); > > if (status < 0) > return status; > > - return spi_write(spi, buf, buf_size); > + return spi_write_then_read(priv->spi, buf, buf_size, NULL, 0); > } > > -static int mpf_spi_write_then_read(struct spi_device *spi, > +static int mpf_spi_write_then_read(struct mpf_priv *priv, > const void *txbuf, size_t txbuf_size, > void *rxbuf, size_t rxbuf_size) > { > const u8 read_command[] = { MPF_SPI_READ_DATA }; > int ret; > > - ret = mpf_spi_write(spi, txbuf, txbuf_size); > + ret = mpf_spi_write(priv, txbuf, txbuf_size); > if (ret) > return ret; > > - ret = mpf_poll_status(spi, MPF_STATUS_READY); > + ret = mpf_poll_status(priv, MPF_STATUS_READY); > if (ret < 0) > return ret; > > - return spi_write_then_read(spi, read_command, sizeof(read_command), > + return spi_write_then_read(priv->spi, read_command, sizeof(read_command), > rxbuf, rxbuf_size); > } > > @@ -242,7 +247,6 @@ static int mpf_ops_write_init(struct fpga_manager *mgr, > const u8 isc_en_command[] = { MPF_SPI_ISC_ENABLE }; > struct mpf_priv *priv = mgr->priv; > struct device *dev = &mgr->dev; > - struct spi_device *spi; > u32 isc_ret = 0; > int ret; > > @@ -251,9 +255,7 @@ static int mpf_ops_write_init(struct fpga_manager *mgr, > return -EOPNOTSUPP; > } > > - spi = priv->spi; > - > - ret = mpf_spi_write_then_read(spi, isc_en_command, sizeof(isc_en_command), > + ret = mpf_spi_write_then_read(priv, isc_en_command, sizeof(isc_en_command), > &isc_ret, sizeof(isc_ret)); > if (ret || isc_ret) { > dev_err(dev, "Failed to enable ISC: spi_ret %d, isc_ret %u\n", > @@ -261,7 +263,7 @@ static int mpf_ops_write_init(struct fpga_manager *mgr, > return -EFAULT; > } > > - ret = mpf_spi_write(spi, program_mode, sizeof(program_mode)); > + ret = mpf_spi_write(priv, program_mode, sizeof(program_mode)); > if (ret) { > dev_err(dev, "Failed to enter program mode: %d\n", ret); > return ret; > @@ -272,13 +274,32 @@ static int mpf_ops_write_init(struct fpga_manager *mgr, > return 0; > } > > +static int mpf_spi_frame_write(struct mpf_priv *priv, const char *buf) > +{ > + struct spi_transfer xfers[2] = { > + { > + .tx_buf = priv->tx, > + .len = 1, > + }, { > + .tx_buf = buf, > + .len = MPF_SPI_FRAME_SIZE, > + }, > + }; > + int ret; > + > + ret = mpf_poll_status(priv, 0); > + if (ret < 0) > + return ret; > + > + *priv->tx = MPF_SPI_FRAME; > + > + return spi_sync_transfer(priv->spi, xfers, ARRAY_SIZE(xfers)); > +} > + > static int mpf_ops_write(struct fpga_manager *mgr, const char *buf, size_t count) > { > - u8 spi_frame_command[] = { MPF_SPI_FRAME }; > - struct spi_transfer xfers[2] = { 0 }; > struct mpf_priv *priv = mgr->priv; > struct device *dev = &mgr->dev; > - struct spi_device *spi; > int ret, i; > > if (count % MPF_SPI_FRAME_SIZE) { > @@ -287,19 +308,8 @@ static int mpf_ops_write(struct fpga_manager *mgr, const char *buf, size_t count > return -EINVAL; > } > > - spi = priv->spi; > - > - xfers[0].tx_buf = spi_frame_command; > - xfers[0].len = sizeof(spi_frame_command); > - > for (i = 0; i < count / MPF_SPI_FRAME_SIZE; i++) { > - xfers[1].tx_buf = buf + i * MPF_SPI_FRAME_SIZE; > - xfers[1].len = MPF_SPI_FRAME_SIZE; > - > - ret = mpf_poll_status(spi, 0); > - if (ret >= 0) > - ret = spi_sync_transfer(spi, xfers, ARRAY_SIZE(xfers)); > - > + ret = mpf_spi_frame_write(priv, buf + i * MPF_SPI_FRAME_SIZE); > if (ret) { > dev_err(dev, "Failed to write bitstream frame %d/%zu\n", > i, count / MPF_SPI_FRAME_SIZE); > @@ -317,12 +327,9 @@ static int mpf_ops_write_complete(struct fpga_manager *mgr, > const u8 release_command[] = { MPF_SPI_RELEASE }; > struct mpf_priv *priv = mgr->priv; > struct device *dev = &mgr->dev; > - struct spi_device *spi; > int ret; > > - spi = priv->spi; > - > - ret = mpf_spi_write(spi, isc_dis_command, sizeof(isc_dis_command)); > + ret = mpf_spi_write(priv, isc_dis_command, sizeof(isc_dis_command)); > if (ret) { > dev_err(dev, "Failed to disable ISC: %d\n", ret); > return ret; > @@ -330,7 +337,7 @@ static int mpf_ops_write_complete(struct fpga_manager *mgr, > > usleep_range(1000, 2000); > > - ret = mpf_spi_write(spi, release_command, sizeof(release_command)); > + ret = mpf_spi_write(priv, release_command, sizeof(release_command)); > if (ret) { > dev_err(dev, "Failed to exit program mode: %d\n", ret); > return ret; > @@ -361,6 +368,14 @@ static int mpf_probe(struct spi_device *spi) > if (!priv) > return -ENOMEM; > > + priv->tx = devm_kmalloc(dev, 1, GFP_KERNEL); > + if (!priv->tx) > + return -ENOMEM; > + > + priv->rx = devm_kmalloc(dev, 1, GFP_KERNEL); > + if (!priv->rx) > + return -ENOMEM; > + > priv->spi = spi; > > mgr = devm_fpga_mgr_register(dev, "Microchip Polarfire SPI FPGA Manager", > -- > 2.38.2 > >
diff --git a/drivers/fpga/microchip-spi.c b/drivers/fpga/microchip-spi.c index 7436976ea904..dfb4e071db86 100644 --- a/drivers/fpga/microchip-spi.c +++ b/drivers/fpga/microchip-spi.c @@ -6,6 +6,7 @@ #include <asm/unaligned.h> #include <linux/delay.h> #include <linux/fpga/fpga-mgr.h> +#include <linux/iopoll.h> #include <linux/module.h> #include <linux/of_device.h> #include <linux/spi/spi.h> @@ -33,7 +34,6 @@ #define MPF_BITS_PER_COMPONENT_SIZE 22 -#define MPF_STATUS_POLL_RETRIES 10000 #define MPF_STATUS_BUSY BIT(0) #define MPF_STATUS_READY BIT(1) #define MPF_STATUS_SPI_VIOLATION BIT(2) @@ -42,46 +42,55 @@ struct mpf_priv { struct spi_device *spi; bool program_mode; + u8 *tx; + u8 *rx; }; -static int mpf_read_status(struct spi_device *spi) +static int mpf_read_status(struct mpf_priv *priv) { - u8 status = 0, status_command = MPF_SPI_READ_STATUS; - struct spi_transfer xfers[2] = { 0 }; - int ret; - /* * HW status is returned on MISO in the first byte after CS went * active. However, first reading can be inadequate, so we submit * two identical SPI transfers and use result of the later one. */ - xfers[0].tx_buf = &status_command; - xfers[1].tx_buf = &status_command; - xfers[0].rx_buf = &status; - xfers[1].rx_buf = &status; - xfers[0].len = 1; - xfers[1].len = 1; - xfers[0].cs_change = 1; + struct spi_transfer xfers[2] = { + { + .tx_buf = priv->tx, + .rx_buf = priv->rx, + .len = 1, + .cs_change = 1, + }, { + .tx_buf = priv->tx, + .rx_buf = priv->rx, + .len = 1, + }, + }; + u8 status; + int ret; - ret = spi_sync_transfer(spi, xfers, 2); + *priv->tx = MPF_SPI_READ_STATUS; + + ret = spi_sync_transfer(priv->spi, xfers, 2); + if (ret) + return ret; + + status = *priv->rx; if ((status & MPF_STATUS_SPI_VIOLATION) || (status & MPF_STATUS_SPI_ERROR)) - ret = -EIO; + return -EIO; - return ret ? : status; + return status; } static enum fpga_mgr_states mpf_ops_state(struct fpga_manager *mgr) { struct mpf_priv *priv = mgr->priv; - struct spi_device *spi; bool program_mode; int status; - spi = priv->spi; program_mode = priv->program_mode; - status = mpf_read_status(spi); + status = mpf_read_status(priv); if (!program_mode && !status) return FPGA_MGR_STATE_OPERATING; @@ -186,51 +195,47 @@ static int mpf_ops_parse_header(struct fpga_manager *mgr, } /* Poll HW status until busy bit is cleared and mask bits are set. */ -static int mpf_poll_status(struct spi_device *spi, u8 mask) +static int mpf_poll_status(struct mpf_priv *priv, u8 mask) { - int status, retries = MPF_STATUS_POLL_RETRIES; - - while (retries--) { - status = mpf_read_status(spi); - if (status < 0) - return status; + int ret, status; - if (status & MPF_STATUS_BUSY) - continue; - - if (!mask || (status & mask)) - return status; - } + ret = read_poll_timeout(mpf_read_status, status, + (status < 0) || + (!(status & MPF_STATUS_BUSY) && + (!mask || (status & mask))), + 0, 2 * USEC_PER_SEC, false, priv); + if (ret < 0) + return ret; - return -EBUSY; + return status; } -static int mpf_spi_write(struct spi_device *spi, const void *buf, size_t buf_size) +static int mpf_spi_write(struct mpf_priv *priv, const void *buf, size_t buf_size) { - int status = mpf_poll_status(spi, 0); + int status = mpf_poll_status(priv, 0); if (status < 0) return status; - return spi_write(spi, buf, buf_size); + return spi_write_then_read(priv->spi, buf, buf_size, NULL, 0); } -static int mpf_spi_write_then_read(struct spi_device *spi, +static int mpf_spi_write_then_read(struct mpf_priv *priv, const void *txbuf, size_t txbuf_size, void *rxbuf, size_t rxbuf_size) { const u8 read_command[] = { MPF_SPI_READ_DATA }; int ret; - ret = mpf_spi_write(spi, txbuf, txbuf_size); + ret = mpf_spi_write(priv, txbuf, txbuf_size); if (ret) return ret; - ret = mpf_poll_status(spi, MPF_STATUS_READY); + ret = mpf_poll_status(priv, MPF_STATUS_READY); if (ret < 0) return ret; - return spi_write_then_read(spi, read_command, sizeof(read_command), + return spi_write_then_read(priv->spi, read_command, sizeof(read_command), rxbuf, rxbuf_size); } @@ -242,7 +247,6 @@ static int mpf_ops_write_init(struct fpga_manager *mgr, const u8 isc_en_command[] = { MPF_SPI_ISC_ENABLE }; struct mpf_priv *priv = mgr->priv; struct device *dev = &mgr->dev; - struct spi_device *spi; u32 isc_ret = 0; int ret; @@ -251,9 +255,7 @@ static int mpf_ops_write_init(struct fpga_manager *mgr, return -EOPNOTSUPP; } - spi = priv->spi; - - ret = mpf_spi_write_then_read(spi, isc_en_command, sizeof(isc_en_command), + ret = mpf_spi_write_then_read(priv, isc_en_command, sizeof(isc_en_command), &isc_ret, sizeof(isc_ret)); if (ret || isc_ret) { dev_err(dev, "Failed to enable ISC: spi_ret %d, isc_ret %u\n", @@ -261,7 +263,7 @@ static int mpf_ops_write_init(struct fpga_manager *mgr, return -EFAULT; } - ret = mpf_spi_write(spi, program_mode, sizeof(program_mode)); + ret = mpf_spi_write(priv, program_mode, sizeof(program_mode)); if (ret) { dev_err(dev, "Failed to enter program mode: %d\n", ret); return ret; @@ -272,13 +274,32 @@ static int mpf_ops_write_init(struct fpga_manager *mgr, return 0; } +static int mpf_spi_frame_write(struct mpf_priv *priv, const char *buf) +{ + struct spi_transfer xfers[2] = { + { + .tx_buf = priv->tx, + .len = 1, + }, { + .tx_buf = buf, + .len = MPF_SPI_FRAME_SIZE, + }, + }; + int ret; + + ret = mpf_poll_status(priv, 0); + if (ret < 0) + return ret; + + *priv->tx = MPF_SPI_FRAME; + + return spi_sync_transfer(priv->spi, xfers, ARRAY_SIZE(xfers)); +} + static int mpf_ops_write(struct fpga_manager *mgr, const char *buf, size_t count) { - u8 spi_frame_command[] = { MPF_SPI_FRAME }; - struct spi_transfer xfers[2] = { 0 }; struct mpf_priv *priv = mgr->priv; struct device *dev = &mgr->dev; - struct spi_device *spi; int ret, i; if (count % MPF_SPI_FRAME_SIZE) { @@ -287,19 +308,8 @@ static int mpf_ops_write(struct fpga_manager *mgr, const char *buf, size_t count return -EINVAL; } - spi = priv->spi; - - xfers[0].tx_buf = spi_frame_command; - xfers[0].len = sizeof(spi_frame_command); - for (i = 0; i < count / MPF_SPI_FRAME_SIZE; i++) { - xfers[1].tx_buf = buf + i * MPF_SPI_FRAME_SIZE; - xfers[1].len = MPF_SPI_FRAME_SIZE; - - ret = mpf_poll_status(spi, 0); - if (ret >= 0) - ret = spi_sync_transfer(spi, xfers, ARRAY_SIZE(xfers)); - + ret = mpf_spi_frame_write(priv, buf + i * MPF_SPI_FRAME_SIZE); if (ret) { dev_err(dev, "Failed to write bitstream frame %d/%zu\n", i, count / MPF_SPI_FRAME_SIZE); @@ -317,12 +327,9 @@ static int mpf_ops_write_complete(struct fpga_manager *mgr, const u8 release_command[] = { MPF_SPI_RELEASE }; struct mpf_priv *priv = mgr->priv; struct device *dev = &mgr->dev; - struct spi_device *spi; int ret; - spi = priv->spi; - - ret = mpf_spi_write(spi, isc_dis_command, sizeof(isc_dis_command)); + ret = mpf_spi_write(priv, isc_dis_command, sizeof(isc_dis_command)); if (ret) { dev_err(dev, "Failed to disable ISC: %d\n", ret); return ret; @@ -330,7 +337,7 @@ static int mpf_ops_write_complete(struct fpga_manager *mgr, usleep_range(1000, 2000); - ret = mpf_spi_write(spi, release_command, sizeof(release_command)); + ret = mpf_spi_write(priv, release_command, sizeof(release_command)); if (ret) { dev_err(dev, "Failed to exit program mode: %d\n", ret); return ret; @@ -361,6 +368,14 @@ static int mpf_probe(struct spi_device *spi) if (!priv) return -ENOMEM; + priv->tx = devm_kmalloc(dev, 1, GFP_KERNEL); + if (!priv->tx) + return -ENOMEM; + + priv->rx = devm_kmalloc(dev, 1, GFP_KERNEL); + if (!priv->rx) + return -ENOMEM; + priv->spi = spi; mgr = devm_fpga_mgr_register(dev, "Microchip Polarfire SPI FPGA Manager",