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Subject[PATCH v8 3/3] usb: xhci: configure 32-bit DMA if the controller does not support 64-bit DMA
Date
This change avoids DMA error in the cases where dma_mask and
coherent_dma_mask of a 32-bit controller get configured as
DMA_BIT_MASK(64) when running on a 64-bit system.

Signed-off-by: Duc Dang <dhdang@apm.com>
---
drivers/usb/host/xhci.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 6b0f4a4..8cb8f39 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -4908,6 +4908,16 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
!dma_set_mask(dev, DMA_BIT_MASK(64))) {
xhci_dbg(xhci, "Enabling 64-bit DMA addresses.\n");
dma_set_coherent_mask(dev, DMA_BIT_MASK(64));
+ } else {
+ /*
+ * This is to avoid error in cases where a 32-bit USB
+ * controller is used on a 64-bit capable system.
+ */
+ retval = dma_set_mask(dev, DMA_BIT_MASK(32));
+ if (retval)
+ return retval;
+ xhci_dbg(xhci, "Enabling 32-bit DMA addresses.\n");
+ dma_set_coherent_mask(dev, DMA_BIT_MASK(32));
}

xhci_dbg(xhci, "Calling HCD init\n");
--
1.9.1


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