[PATCH v9 06/14] spi: imx: add dma_sync_sg_for_device after fallback from dma

[Robin Gong <yibin.gong@xxxxxxx>]

In case dma transfer failed and fallback to pio, tx_buf/rx_buf need to be
taken care cache since they have already been maintained by spi.c

Fixes: bcd8e7761ec9("spi: imx: fallback to PIO if dma setup failure")
Signed-off-by: Robin Gong <yibin.gong@xxxxxxx>
Reported-by: Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/linux-arm-kernel/5d246dd81607bb6e5cb9af86ad4e53f7a7a99c50.camel@xxxxxxxxxxxxxxx/

---
 drivers/spi/spi-imx.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index b7a85e3..c51cd3a 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -1456,6 +1456,13 @@ static int spi_imx_pio_transfer(struct spi_device *spi,
 		return -ETIMEDOUT;
 	}
 
+	if (transfer->rx_sg.sgl) {
+		struct device *rx_dev = spi->controller->dma_rx->device->dev;
+
+		dma_sync_sg_for_device(rx_dev, transfer->rx_sg.sgl,
+				       transfer->rx_sg.nents, DMA_TO_DEVICE);
+	}
+
 	return transfer->len;
 }
 
@@ -1521,10 +1528,15 @@ static int spi_imx_transfer(struct spi_device *spi,
 	 * firmware may not be updated as ERR009165 required.
 	 */
 	if (spi_imx->usedma) {
+		struct device *tx_dev = spi->controller->dma_tx->device->dev;
+
 		ret = spi_imx_dma_transfer(spi_imx, transfer);
 		if (ret != -EINVAL)
 			return ret;
 
+		dma_sync_sg_for_cpu(tx_dev, transfer->tx_sg.sgl,
+				    transfer->tx_sg.nents, DMA_FROM_DEVICE);
+
 		spi_imx->devtype_data->disable_dma(spi_imx);
 
 		spi_imx->usedma = false;
-- 
2.7.4