usb: make xhci platform driver use 64 bit or 32 bit DMA

The xhci platform driver needs to work on systems that either only
support 64-bit DMA or only support 32-bit DMA. Attempt to set a
coherent dma mask for 64-bit DMA, and attempt again with 32-bit
DMA if that fails.

Signed-off-by: Mark Langsdorf <mlangsdo@redhat.com>

diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
index 890ad9d9d32991c7e74b02d9580b5cfbcd4d595e..122b1fb12b7ed2c2d54a6adf67847a9e81380235 100644 (file)
--- a/drivers/usb/host/xhci-plat.c
+++ b/drivers/usb/host/xhci-plat.c
@@ -93,14 +93,13 @@ static int xhci_plat_probe(struct platform_device *pdev)
        if (irq < 0)
                return -ENODEV;
 
-       /* Initialize dma_mask and coherent_dma_mask to 32-bits */
-       ret = dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32));
-       if (ret)
-               return ret;
-       if (!pdev->dev.dma_mask)
-               pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
-       else
-               dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
+       /* Try setting the coherent_dma_mask to 64 bits, then try 32 bits */
+       ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
+       if (ret) {
+               ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
+               if (ret)
+                       return ret;
+       }
 
        hcd = usb_create_hcd(driver, &pdev->dev, dev_name(&pdev->dev));
        if (!hcd)