spi: spi-fsl-dspi: fix DMA mapping

Use the correct device to request the DMA mapping. Otherwise the IOMMU
doesn't get the mapping and it will generate a page fault.

The error messages look like:
[    3.008452] arm-smmu 5000000.iommu: Unhandled context fault: fsr=0x402, iova=0xf9800000, fsynr=0x3f0022, cbfrsynra=0x828, cb=8
[    3.020123] arm-smmu 5000000.iommu: Unhandled context fault: fsr=0x402, iova=0xf9800000, fsynr=0x3f0022, cbfrsynra=0x828, cb=8

This was tested on a custom board with a LS1028A SoC.
Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200310073313.21277-1-michael@walle.ccSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-fsl-dspi.c

@@ -497,14 +497,16 @@ static int dspi_request_dma(struct fsl_dspi *dspi, phys_addr_t phy_addr)
 		goto err_tx_channel;
 	}
 
-	dma->tx_dma_buf = dma_alloc_coherent(dev, dspi->devtype_data->dma_bufsize,
+	dma->tx_dma_buf = dma_alloc_coherent(dma->chan_tx->device->dev,
+					     dspi->devtype_data->dma_bufsize,
 					     &dma->tx_dma_phys, GFP_KERNEL);
 	if (!dma->tx_dma_buf) {
 		ret = -ENOMEM;
 		goto err_tx_dma_buf;
 	}
 
-	dma->rx_dma_buf = dma_alloc_coherent(dev, dspi->devtype_data->dma_bufsize,
+	dma->rx_dma_buf = dma_alloc_coherent(dma->chan_rx->device->dev,
+					     dspi->devtype_data->dma_bufsize,
 					     &dma->rx_dma_phys, GFP_KERNEL);
 	if (!dma->rx_dma_buf) {
 		ret = -ENOMEM;
@@ -541,10 +543,12 @@ static int dspi_request_dma(struct fsl_dspi *dspi, phys_addr_t phy_addr)
 	return 0;
 
 err_slave_config:
-	dma_free_coherent(dev, dspi->devtype_data->dma_bufsize,
+	dma_free_coherent(dma->chan_rx->device->dev,
+			  dspi->devtype_data->dma_bufsize,
 			  dma->rx_dma_buf, dma->rx_dma_phys);
 err_rx_dma_buf:
-	dma_free_coherent(dev, dspi->devtype_data->dma_bufsize,
+	dma_free_coherent(dma->chan_tx->device->dev,
+			  dspi->devtype_data->dma_bufsize,
 			  dma->tx_dma_buf, dma->tx_dma_phys);
 err_tx_dma_buf:
 	dma_release_channel(dma->chan_tx);
@@ -560,20 +564,19 @@ static int dspi_request_dma(struct fsl_dspi *dspi, phys_addr_t phy_addr)
 static void dspi_release_dma(struct fsl_dspi *dspi)
 {
 	struct fsl_dspi_dma *dma = dspi->dma;
-	struct device *dev = &dspi->pdev->dev;
 
 	if (!dma)
 		return;
 
 	if (dma->chan_tx) {
-		dma_unmap_single(dev, dma->tx_dma_phys,
+		dma_unmap_single(dma->chan_tx->device->dev, dma->tx_dma_phys,
 				 dspi->devtype_data->dma_bufsize,
 				 DMA_TO_DEVICE);
 		dma_release_channel(dma->chan_tx);
 	}
 
 	if (dma->chan_rx) {
-		dma_unmap_single(dev, dma->rx_dma_phys,
+		dma_unmap_single(dma->chan_rx->device->dev, dma->rx_dma_phys,
 				 dspi->devtype_data->dma_bufsize,
 				 DMA_FROM_DEVICE);
 		dma_release_channel(dma->chan_rx);