1 files changed, 39 insertions, 2 deletions

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index 730b9fd26685..0ef16900efed 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -1166,7 +1166,7 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
                                 xhci_set_link_state(xhci, port_array, wIndex,
                                                         XDEV_RESUME);
                                 spin_unlock_irqrestore(&xhci->lock, flags);
-                                msleep(20);
+                                msleep(USB_RESUME_TIMEOUT);
                                 spin_lock_irqsave(&xhci->lock, flags);
                                 xhci_set_link_state(xhci, port_array, wIndex,
                                                         XDEV_U0);
@@ -1355,6 +1355,35 @@ int xhci_bus_suspend(struct usb_hcd *hcd)
         return 0;
 }
 
+/*
+ * Workaround for missing Cold Attach Status (CAS) if device re-plugged in S3.
+ * warm reset a USB3 device stuck in polling or compliance mode after resume.
+ * See Intel 100/c230 series PCH specification update Doc #332692-006 Errata #8
+ */
+static bool xhci_port_missing_cas_quirk(int port_index,
+                                             __le32 __iomem **port_array)
+{
+        u32 portsc;
+
+        portsc = readl(port_array[port_index]);
+
+        /* if any of these are set we are not stuck */
+        if (portsc & (PORT_CONNECT | PORT_CAS))
+                return false;
+
+        if (((portsc & PORT_PLS_MASK) != XDEV_POLLING) &&
+            ((portsc & PORT_PLS_MASK) != XDEV_COMP_MODE))
+                return false;
+
+        /* clear wakeup/change bits, and do a warm port reset */
+        portsc &= ~(PORT_RWC_BITS | PORT_CEC | PORT_WAKE_BITS);
+        portsc |= PORT_WR;
+        writel(portsc, port_array[port_index]);
+        /* flush write */
+        readl(port_array[port_index]);
+        return true;
+}
+
 int xhci_bus_resume(struct usb_hcd *hcd)
 {
         struct xhci_hcd *xhci = hcd_to_xhci(hcd);
@@ -1392,6 +1421,14 @@ int xhci_bus_resume(struct usb_hcd *hcd)
                 u32 temp;
 
                 temp = readl(port_array[port_index]);
+
+                /* warm reset CAS limited ports stuck in polling/compliance */
+                if ((xhci->quirks & XHCI_MISSING_CAS) &&
+                    (hcd->speed >= HCD_USB3) &&
+                    xhci_port_missing_cas_quirk(port_index, port_array)) {
+                        xhci_dbg(xhci, "reset stuck port %d\n", port_index);
+                        continue;
+                }
                 if (DEV_SUPERSPEED_ANY(temp))
                         temp &= ~(PORT_RWC_BITS | PORT_CEC | PORT_WAKE_BITS);
                 else
@@ -1410,7 +1447,7 @@ int xhci_bus_resume(struct usb_hcd *hcd)
 
         if (need_usb2_u3_exit) {
                 spin_unlock_irqrestore(&xhci->lock, flags);
-                msleep(20);
+                msleep(USB_RESUME_TIMEOUT);
                 spin_lock_irqsave(&xhci->lock, flags);
         }