usb: xhci: configure 32-bit DMA if the controller does not support 64-bit DMA

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>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 49a41c7..6e7dc6f 100644 (file)
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -4913,6 +4913,16 @@ 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");