3 files changed, 27 insertions, 0 deletions

diff --git a/drivers/usb/host/xhci-ext-caps.h b/drivers/usb/host/xhci-ext-caps.h
index ce5c9e51748e..c7f33123d4c0 100644
--- a/drivers/usb/host/xhci-ext-caps.h
+++ b/drivers/usb/host/xhci-ext-caps.h
@@ -65,6 +65,12 @@
 /* bits 1:2, 5:12, and 17:19 need to be preserved; bits 21:28 should be zero */
 #define XHCI_LEGACY_DISABLE_SMI         ((0x3 << 1) + (0xff << 5) + (0x7 << 17))
 
+/* USB 2.0 xHCI 0.96 L1C capability - section 7.2.2.1.3.2 */
+#define XHCI_L1C               (1 << 16)
+
+/* USB 2.0 xHCI 1.0 hardware LMP capability - section 7.2.2.1.3.2 */
+#define XHCI_HLC               (1 << 19)
+
 /* command register values to disable interrupts and halt the HC */
 /* start/stop HC execution - do not write unless HC is halted*/
 #define XHCI_CMD_RUN            (1 << 0)
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index bc6ec0cb3c61..9c7ddf0f3a43 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -1959,6 +1959,23 @@ static void xhci_add_in_port(struct xhci_hcd *xhci, unsigned int num_ports,
         if (port_offset == 0 || (port_offset + port_count - 1) > num_ports)
                 /* WTF? "Valid values are ‘1’ to MaxPorts" */
                 return;
+
+        /* Check the host's USB2 LPM capability */
+        if ((xhci->hci_version == 0x96) && (major_revision != 0x03) &&
+                        (temp & XHCI_L1C)) {
+                xhci_dbg(xhci, "xHCI 0.96: support USB2 software lpm\n");
+                xhci->sw_lpm_support = 1;
+        }
+
+        if ((xhci->hci_version >= 0x100) && (major_revision != 0x03)) {
+                xhci_dbg(xhci, "xHCI 1.0: support USB2 software lpm\n");
+                xhci->sw_lpm_support = 1;
+                if (temp & XHCI_HLC) {
+                        xhci_dbg(xhci, "xHCI 1.0: support USB2 hardware lpm\n");
+                        xhci->hw_lpm_support = 1;
+                }
+        }
+
         port_offset--;
         for (i = port_offset; i < (port_offset + port_count); i++) {
                 /* Duplicate entry.  Ignore the port if the revisions differ. */
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index fa921cbbe872..8673f985046e 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1459,6 +1459,10 @@ struct xhci_hcd {
         /* Array of pointers to USB 2.0 PORTSC registers */
         __le32 __iomem          **usb2_ports;
         unsigned int            num_usb2_ports;
+        /* support xHCI 0.96 spec USB2 software LPM */
+        unsigned                sw_lpm_support:1;
+        /* support xHCI 1.0 spec USB2 hardware LPM */
+        unsigned                hw_lpm_support:1;
 };
 
 /* convert between an HCD pointer and the corresponding EHCI_HCD */