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authorDuc Dang <dhdang@apm.com>2015-10-09 13:30:11 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-10-16 23:34:22 -0700
commit0ebbe398f68be0d9bbd41dcfb57319e697756b37 (patch)
tree3a212cfa00f80aff88db6ef423b3a2a18cad0481 /drivers/usb
parent8451a34ff6c7c756e9e0f0094a3ba856c9734e5d (diff)
downloadlinux-0ebbe398f68be0d9bbd41dcfb57319e697756b37.tar.gz
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.

[dhdang: regenerate the patch over v4.3-rc1 and address new comments]
Signed-off-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Duc Dang <dhdang@apm.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb')
-rw-r--r--drivers/usb/host/xhci-plat.c20
1 files changed, 13 insertions, 7 deletions
diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
index 890ad9d9d329..34c93e87b2d3 100644
--- a/drivers/usb/host/xhci-plat.c
+++ b/drivers/usb/host/xhci-plat.c
@@ -93,14 +93,20 @@ 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;
+	/* Try to set 64-bit DMA first */
+	if (WARN_ON(!pdev->dev.dma_mask))
+		/* Platform did not initialize dma_mask */
+		ret = dma_coerce_mask_and_coherent(&pdev->dev,
+						   DMA_BIT_MASK(64));
 	else
-		dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
+		ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
+
+	/* If seting 64-bit DMA mask fails, fall back to 32-bit DMA mask */
+	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)