aboutsummaryrefslogtreecommitdiff
path: root/drivers/usb/host/xhci-hub.c
diff options
context:
space:
mode:
authorSarah Sharp <sarah.a.sharp@linux.intel.com>2012-06-25 08:24:30 -0700
committerSarah Sharp <sarah.a.sharp@linux.intel.com>2012-07-11 07:06:48 -0400
commitaf3a23ef4e5fbaf33f0afdda7d26442f036ba795 (patch)
tree0c88de5b3c224cc720dbb2b63b4b9e5def22ea05 /drivers/usb/host/xhci-hub.c
parentc5c4bdf02e518a281b229ae0891b346919e2d291 (diff)
downloadlinux-linaro-stable-af3a23ef4e5fbaf33f0afdda7d26442f036ba795.tar.gz
xhci: Export Latency Tolerance Messaging capabilities.
Some xHCI host controllers may have optional support for Latency Tolerance Messaging (LTM). This allows USB 3.0 devices that support LTM to pass information about how much latency they can tolerate to the xHC. A PCI xHCI host will use this information to update the PCI Latency Tolerance Request (LTR) info. The goal of this is to gather latency information for the system, to enable hardware-driven C states, and the shutting down of PLLs. Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Diffstat (limited to 'drivers/usb/host/xhci-hub.c')
-rw-r--r--drivers/usb/host/xhci-hub.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index 2732ef660c5c..6d21030e2b7b 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -508,12 +508,18 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
if (hcd->speed != HCD_USB3)
goto error;
+ /* Set the U1 and U2 exit latencies. */
memcpy(buf, &usb_bos_descriptor,
USB_DT_BOS_SIZE + USB_DT_USB_SS_CAP_SIZE);
temp = xhci_readl(xhci, &xhci->cap_regs->hcs_params3);
buf[12] = HCS_U1_LATENCY(temp);
put_unaligned_le16(HCS_U2_LATENCY(temp), &buf[13]);
+ /* Indicate whether the host has LTM support. */
+ temp = xhci_readl(xhci, &xhci->cap_regs->hcc_params);
+ if (HCC_LTC(temp))
+ buf[8] |= USB_LTM_SUPPORT;
+
spin_unlock_irqrestore(&xhci->lock, flags);
return USB_DT_BOS_SIZE + USB_DT_USB_SS_CAP_SIZE;
case GetPortStatus: