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From: Mark Langsdorf <mlangsdo@redhat.com>
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Date: Wed, 25 Mar 2015 14:12:51 -0400
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Subject: [PATCH] usb: make xhci platform driver use 64 bit or 32 bit DMA
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The xhci platform driver needs to work on systems that either only
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support 64-bit DMA or only support 32-bit DMA. Attempt to set a
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coherent dma mask for 64-bit DMA, and attempt again with 32-bit
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DMA if that fails.
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Signed-off-by: Mark Langsdorf <mlangsdo@redhat.com>
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---
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 drivers/usb/host/xhci-plat.c | 15 +++++++--------
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 1 file changed, 7 insertions(+), 8 deletions(-)
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diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
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index 783e819139a7..4f93ef6942d8 100644
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--- a/drivers/usb/host/xhci-plat.c
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+++ b/drivers/usb/host/xhci-plat.c
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@@ -84,14 +84,13 @@ static int xhci_plat_probe(struct platform_device *pdev)
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 	if (irq < 0)
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 		return -ENODEV;
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-	/* Initialize dma_mask and coherent_dma_mask to 32-bits */
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-	ret = dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32));
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-	if (ret)
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-		return ret;
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-	if (!pdev->dev.dma_mask)
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-		pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
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-	else
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-		dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
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+	/* Try setting the coherent_dma_mask to 64 bits, then try 32 bits */
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+	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
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+	if (ret) {
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+		ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
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+		if (ret)
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+			return ret;
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+	}
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 	hcd = usb_create_hcd(driver, &pdev->dev, dev_name(&pdev->dev));
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 	if (!hcd)