[PATCH v2] spi: spi-cadence-quadspi: Fix mapping of buffers for DMA reads

[PATCH v2] spi: spi-cadence-quadspi: Fix mapping of buffers for DMA reads

[Vignesh Raghavendra]

Buffers need to mapped to DMA channel's device pointer instead of SPI
controller's device pointer as its system DMA that actually does data
transfer.
Data inconsistencies have been reported when reading from flash
without this fix.

Fixes: ffa639e069fb ("mtd: spi-nor: cadence-quadspi: Add DMA support for direct mode reads")
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Tested-by: Jan Kiszka <jan.kiszka@siemens.com>
---

v2:
Update the Fixes tag and add collect tested-by

 drivers/spi/spi-cadence-quadspi.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c
index 508b219eabf8..c6795c684b16 100644
--- a/drivers/spi/spi-cadence-quadspi.c
+++ b/drivers/spi/spi-cadence-quadspi.c
@@ -907,14 +907,16 @@ static int cqspi_direct_read_execute(struct cqspi_flash_pdata *f_pdata,
 	struct dma_async_tx_descriptor *tx;
 	dma_cookie_t cookie;
 	dma_addr_t dma_dst;
+	struct device *ddev;
 
 	if (!cqspi->rx_chan || !virt_addr_valid(buf)) {
 		memcpy_fromio(buf, cqspi->ahb_base + from, len);
 		return 0;
 	}
 
-	dma_dst = dma_map_single(dev, buf, len, DMA_FROM_DEVICE);
-	if (dma_mapping_error(dev, dma_dst)) {
+	ddev = cqspi->rx_chan->device->dev;
+	dma_dst = dma_map_single(ddev, buf, len, DMA_FROM_DEVICE);
+	if (dma_mapping_error(ddev, dma_dst)) {
 		dev_err(dev, "dma mapping failed\n");
 		return -ENOMEM;
 	}
@@ -948,7 +950,7 @@ static int cqspi_direct_read_execute(struct cqspi_flash_pdata *f_pdata,
 	}
 
 err_unmap:
-	dma_unmap_single(dev, dma_dst, len, DMA_FROM_DEVICE);
+	dma_unmap_single(ddev, dma_dst, len, DMA_FROM_DEVICE);
 
 	return ret;
 }
-- 
2.28.0

Re: [PATCH v2] spi: spi-cadence-quadspi: Fix mapping of buffers for DMA reads

[Mark Brown]

On Mon, 31 Aug 2020 18:37:20 +0530, Vignesh Raghavendra wrote:
> Buffers need to mapped to DMA channel's device pointer instead of SPI
> controller's device pointer as its system DMA that actually does data
> transfer.
> Data inconsistencies have been reported when reading from flash
> without this fix.

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next

Thanks!

[1/1] spi: spi-cadence-quadspi: Fix mapping of buffers for DMA reads
      commit: 83048015ff7710b46e7c489458a93c6fe348229d

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark