From: Ivan Bornyakov i.bornyakov@metrotek.ru
[ Upstream commit 1da53d23a41c5f77963984d8da5623ed56918ada ]
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 cacheline aligned 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.
Fixes: 5f8d4a900830 ("fpga: microchip-spi: add Microchip MPF FPGA manager") Signed-off-by: Ivan Bornyakov i.bornyakov@metrotek.ru Acked-by: Conor Dooley conor.dooley@microchip.com Acked-by: Xu Yilun yilun.xu@intel.com Link: https://lore.kernel.org/r/20221230092922.18822-2-i.bornyakov@metrotek.ru Signed-off-by: Xu Yilun yilun.xu@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/fpga/microchip-spi.c | 93 ++++++++++++++++++------------------ 1 file changed, 47 insertions(+), 46 deletions(-)
diff --git a/drivers/fpga/microchip-spi.c b/drivers/fpga/microchip-spi.c index 7436976ea9048..bb69f5beefe78 100644 --- a/drivers/fpga/microchip-spi.c +++ b/drivers/fpga/microchip-spi.c @@ -42,46 +42,55 @@ struct mpf_priv { struct spi_device *spi; bool program_mode; + u8 tx __aligned(ARCH_KMALLOC_MINALIGN); + 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; + + priv->tx = MPF_SPI_READ_STATUS; + + ret = spi_sync_transfer(priv->spi, xfers, 2); + if (ret) + return ret;
- ret = spi_sync_transfer(spi, xfers, 2); + 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; @@ -186,12 +195,12 @@ 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); + status = mpf_read_status(priv); if (status < 0) return status;
@@ -205,32 +214,32 @@ static int mpf_poll_status(struct spi_device *spi, u8 mask) return -EBUSY; }
-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 +251,6 @@ 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 +259,7 @@ 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 +267,7 @@ 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; @@ -274,11 +280,9 @@ static int mpf_ops_write_init(struct fpga_manager *mgr,
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) { @@ -287,18 +291,18 @@ 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); + xfers[0].tx_buf = &priv->tx; + xfers[0].len = 1;
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_poll_status(priv, 0); + if (ret >= 0) { + priv->tx = MPF_SPI_FRAME; + ret = spi_sync_transfer(priv->spi, xfers, ARRAY_SIZE(xfers)); + }
if (ret) { dev_err(dev, "Failed to write bitstream frame %d/%zu\n", @@ -317,12 +321,9 @@ 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 +331,7 @@ 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;