Tell the USB core that we can do DMA directly (instead of needing it to
memory-map the buffers for PIO). If the xHCI host supports 64-bit addresses,
set the DMA mask accordingly. Otherwise indicate the host can handle 32-bit DMA
addresses.
This improves performance because the USB core doesn't have to spend time
remapping buffers in high memory into the 32-bit address range.
Signed-off-by: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx>
---
drivers/usb/host/xhci-pci.c | 9 +++++++++
1 files changed, 9 insertions(+), 0 deletions(-)
diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 11482b6..f7efe02 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -53,6 +53,7 @@ static int xhci_pci_setup(struct usb_hcd *hcd)
struct xhci_hcd *xhci = hcd_to_xhci(hcd);
struct pci_dev *pdev = to_pci_dev(hcd->self.controller);
int retval;
+ u32 temp;
hcd->self.sg_tablesize = TRBS_PER_SEGMENT - 2;
@@ -93,6 +94,14 @@ static int xhci_pci_setup(struct usb_hcd *hcd)
return retval;
xhci_dbg(xhci, "Reset complete\n");
+ temp = xhci_readl(xhci, &xhci->cap_regs->hcc_params);
+ if (HCC_64BIT_ADDR(temp)) {
+ xhci_dbg(xhci, "Enabling 64-bit DMA addresses.\n");
+ dma_set_mask(hcd->self.controller, DMA_BIT_MASK(64));
+ } else {
+ dma_set_mask(hcd->self.controller, DMA_BIT_MASK(32));
+ }
+
xhci_dbg(xhci, "Calling HCD init\n");
/* Initialize HCD and host controller data structures. */
retval = xhci_init(hcd);
--
1.6.3.3
--
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