spi: Check if transfer is mapped before calling DMA sync APIs

The resent update to remove the orig_nents checks revealed
that not all DMA sync backends can cope with the unallocated
SG list, while supplying orig_nents == 0 (the commit 861370f49ce4
("iommu/dma: force bouncing if the size is not cacheline-aligned"),
for example, makes that happen for the IOMMU case). It means
we have to check if the buffers are DMA mapped before trying
to sync them. Re-introduce that check in a form of calling
->can_dma() in the same way as it's done in the DMA mapping loop
for the SPI transfers.

Reported-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Reported-by: Neil Armstrong <neil.armstrong@linaro.org>
Closes: https://lore.kernel.org/r/8ae675b5-fcf9-4c9b-b06a-4462f70e1322@linaro.org
Closes: https://lore.kernel.org/all/d3679496-2e4e-4a7c-97ed-f193bd53af1d@notapiano
Fixes: 8cc3bad9d9d6 ("spi: Remove unneded check for orig_nents")
Suggested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://msgid.link/r/20240522171018.3362521-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index d40ce0fdb1a81eaef44b28b6255180cfcac79f11..b18a4c871e217fd5b84a42f9147066ec7cfe4893 100644 (file)
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1311,7 +1311,7 @@ static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
        return 0;
 }
 
-static void spi_dma_sync_for_device(struct spi_controller *ctlr,
+static void spi_dma_sync_for_device(struct spi_controller *ctlr, struct spi_message *msg,
                                    struct spi_transfer *xfer)
 {
        struct device *rx_dev = ctlr->cur_rx_dma_dev;
@@ -1320,11 +1320,14 @@ static void spi_dma_sync_for_device(struct spi_controller *ctlr,
        if (!ctlr->cur_msg_mapped)
                return;
 
+       if (!ctlr->can_dma(ctlr, msg->spi, xfer))
+               return;
+
        dma_sync_sgtable_for_device(tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
        dma_sync_sgtable_for_device(rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
 }
 
-static void spi_dma_sync_for_cpu(struct spi_controller *ctlr,
+static void spi_dma_sync_for_cpu(struct spi_controller *ctlr, struct spi_message *msg,
                                 struct spi_transfer *xfer)
 {
        struct device *rx_dev = ctlr->cur_rx_dma_dev;
@@ -1333,6 +1336,9 @@ static void spi_dma_sync_for_cpu(struct spi_controller *ctlr,
        if (!ctlr->cur_msg_mapped)
                return;
 
+       if (!ctlr->can_dma(ctlr, msg->spi, xfer))
+               return;
+
        dma_sync_sgtable_for_cpu(rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
        dma_sync_sgtable_for_cpu(tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
 }
@@ -1350,11 +1356,13 @@ static inline int __spi_unmap_msg(struct spi_controller *ctlr,
 }
 
 static void spi_dma_sync_for_device(struct spi_controller *ctrl,
+                                   struct spi_message *msg,
                                    struct spi_transfer *xfer)
 {
 }
 
 static void spi_dma_sync_for_cpu(struct spi_controller *ctrl,
+                                struct spi_message *msg,
                                 struct spi_transfer *xfer)
 {
 }
@@ -1626,10 +1634,10 @@ static int spi_transfer_one_message(struct spi_controller *ctlr,
                        reinit_completion(&ctlr->xfer_completion);
 
 fallback_pio:
-                       spi_dma_sync_for_device(ctlr, xfer);
+                       spi_dma_sync_for_device(ctlr, msg, xfer);
                        ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
                        if (ret < 0) {
-                               spi_dma_sync_for_cpu(ctlr, xfer);
+                               spi_dma_sync_for_cpu(ctlr, msg, xfer);
 
                                if (ctlr->cur_msg_mapped &&
                                   (xfer->error & SPI_TRANS_FAIL_NO_START)) {
@@ -1654,7 +1662,7 @@ fallback_pio:
                                        msg->status = ret;
                        }
 
-                       spi_dma_sync_for_cpu(ctlr, xfer);
+                       spi_dma_sync_for_cpu(ctlr, msg, xfer);
                } else {
                        if (xfer->len)
                                dev_err(&msg->spi->dev,