From 83048015ff7710b46e7c489458a93c6fe348229d Mon Sep 17 00:00:00 2001
From: Vignesh Raghavendra <vigneshr@ti.com>
Date: Mon, 31 Aug 2020 18:37:20 +0530
Subject: [PATCH] spi: spi-cadence-quadspi: Fix mapping of buffers for DMA reads
Git-commit: 83048015ff7710b46e7c489458a93c6fe348229d
Patch-mainline: v5.9-rc5
References: git-fixes

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>
Link: https://lore.kernel.org/r/20200831130720.4524-1-vigneshr@ti.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 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;
 }
-- 
2.26.2