[PATCH v2 1/2] [usb] make xhci platform driver use 64 bit or 32 bit DMA

Mark Langsdorf
2014-11-04T16:50:32Z

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>
Tested-by: Mark Salter <msalter@redhat.com>
---
Changes from v1:
Consolidated to use dma_set_mask_and_coherent
Got rid of the check against sizeof(dma_addr_t)

drivers/usb/host/xhci-plat.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
index 1a0cf9f..91c7557 100644
--- a/drivers/usb/host/xhci-plat.c
+++ b/drivers/usb/host/xhci-plat.c
@@ -147,14 +147,14 @@ static int xhci_plat_probe(struct platform_device *pdev)
return ret;
}

- /* 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)
--
1.9.3