1 files changed, 126 insertions, 1 deletions

diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
index 2dcf906..1528653 100644
--- a/drivers/usb/core/hcd-pci.c
+++ b/drivers/usb/core/hcd-pci.c
@@ -19,6 +19,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/pci.h>
+#include <linux/pm_runtime.h>
 #include <linux/usb.h>
 
 #include <asm/io.h>
@@ -37,6 +38,122 @@
 
 /* PCI-based HCs are common, but plenty of non-PCI HCs are used too */
 
+#ifdef CONFIG_PM_SLEEP
+
+/* Coordinate handoffs between EHCI and companion controllers
+ * during system resume
+ */
+
+static DEFINE_MUTEX(companions_mutex);
+
+#define CL_UHCI		PCI_CLASS_SERIAL_USB_UHCI
+#define CL_OHCI		PCI_CLASS_SERIAL_USB_OHCI
+#define CL_EHCI		PCI_CLASS_SERIAL_USB_EHCI
+
+enum companion_action {
+	SET_HS_COMPANION, CLEAR_HS_COMPANION, WAIT_FOR_COMPANIONS
+};
+
+static void companion_common(struct pci_dev *pdev, struct usb_hcd *hcd,
+		enum companion_action action)
+{
+	struct pci_dev		*companion;
+	struct usb_hcd		*companion_hcd;
+	unsigned int		slot = PCI_SLOT(pdev->devfn);
+
+	/* Iterate through other PCI functions in the same slot.
+	 * If pdev is OHCI or UHCI then we are looking for EHCI, and
+	 * vice versa.
+	 */
+	companion = NULL;
+	for (;;) {
+		companion = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, companion);
+		if (!companion)
+			break;
+		if (companion->bus != pdev->bus ||
+				PCI_SLOT(companion->devfn) != slot)
+			continue;
+
+		companion_hcd = pci_get_drvdata(companion);
+		if (!companion_hcd)
+			continue;
+
+		/* For SET_HS_COMPANION, store a pointer to the EHCI bus in
+		 * the OHCI/UHCI companion bus structure.
+		 * For CLEAR_HS_COMPANION, clear the pointer to the EHCI bus
+		 * in the OHCI/UHCI companion bus structure.
+		 * For WAIT_FOR_COMPANIONS, wait until the OHCI/UHCI
+		 * companion controllers have fully resumed.
+		 */
+
+		if ((pdev->class == CL_OHCI || pdev->class == CL_UHCI) &&
+				companion->class == CL_EHCI) {
+			/* action must be SET_HS_COMPANION */
+			dev_dbg(&companion->dev, "HS companion for %s\n",
+					dev_name(&pdev->dev));
+			hcd->self.hs_companion = &companion_hcd->self;
+
+		} else if (pdev->class == CL_EHCI &&
+				(companion->class == CL_OHCI ||
+				companion->class == CL_UHCI)) {
+			switch (action) {
+			case SET_HS_COMPANION:
+				dev_dbg(&pdev->dev, "HS companion for %s\n",
+						dev_name(&companion->dev));
+				companion_hcd->self.hs_companion = &hcd->self;
+				break;
+			case CLEAR_HS_COMPANION:
+				companion_hcd->self.hs_companion = NULL;
+				break;
+			case WAIT_FOR_COMPANIONS:
+				device_pm_wait_for_dev(&pdev->dev,
+						&companion->dev);
+				break;
+			}
+		}
+	}
+}
+
+static void set_hs_companion(struct pci_dev *pdev, struct usb_hcd *hcd)
+{
+	mutex_lock(&companions_mutex);
+	dev_set_drvdata(&pdev->dev, hcd);
+	companion_common(pdev, hcd, SET_HS_COMPANION);
+	mutex_unlock(&companions_mutex);
+}
+
+static void clear_hs_companion(struct pci_dev *pdev, struct usb_hcd *hcd)
+{
+	mutex_lock(&companions_mutex);
+	dev_set_drvdata(&pdev->dev, NULL);
+
+	/* If pdev is OHCI or UHCI, just clear its hs_companion pointer */
+	if (pdev->class == CL_OHCI || pdev->class == CL_UHCI)
+		hcd->self.hs_companion = NULL;
+
+	/* Otherwise search for companion buses and clear their pointers */
+	else
+		companion_common(pdev, hcd, CLEAR_HS_COMPANION);
+	mutex_unlock(&companions_mutex);
+}
+
+static void wait_for_companions(struct pci_dev *pdev, struct usb_hcd *hcd)
+{
+	/* Only EHCI controllers need to wait.
+	 * No locking is needed because a controller cannot be resumed
+	 * while one of its companions is getting unbound.
+	 */
+	if (pdev->class == CL_EHCI)
+		companion_common(pdev, hcd, WAIT_FOR_COMPANIONS);
+}
+
+#else /* !CONFIG_PM_SLEEP */
+
+static inline void set_hs_companion(struct pci_dev *d, struct usb_hcd *h) {}
+static inline void clear_hs_companion(struct pci_dev *d, struct usb_hcd *h) {}
+static inline void wait_for_companions(struct pci_dev *d, struct usb_hcd *h) {}
+
+#endif /* !CONFIG_PM_SLEEP */
 
 /*-------------------------------------------------------------------------*/
 
@@ -123,7 +240,7 @@ int usb_hcd_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 		if (region == PCI_ROM_RESOURCE) {
 			dev_dbg(&dev->dev, "no i/o regions available\n");
 			retval = -EBUSY;
-			goto err1;
+			goto err2;
 		}
 	}
 
@@ -132,6 +249,7 @@ int usb_hcd_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	retval = usb_add_hcd(hcd, dev->irq, IRQF_DISABLED | IRQF_SHARED);
 	if (retval != 0)
 		goto err4;
+	set_hs_companion(dev, hcd);
 	return retval;
 
  err4:
@@ -142,6 +260,7 @@ int usb_hcd_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	} else
 		release_region(hcd->rsrc_start, hcd->rsrc_len);
  err2:
+	clear_hs_companion(dev, hcd);
 	usb_put_hcd(hcd);
  err1:
 	pci_disable_device(dev);
@@ -180,6 +299,7 @@ void usb_hcd_pci_remove(struct pci_dev *dev)
 	} else {
 		release_region(hcd->rsrc_start, hcd->rsrc_len);
 	}
+	clear_hs_companion(dev, hcd);
 	usb_put_hcd(hcd);
 	pci_disable_device(dev);
 }
@@ -344,6 +464,11 @@ static int resume_common(struct device *dev, bool hibernated)
 	clear_bit(HCD_FLAG_SAW_IRQ, &hcd->flags);
 
 	if (hcd->driver->pci_resume) {
+		/* This call should be made only during system resume,
+		 * not during runtime resume.
+		 */
+		wait_for_companions(pci_dev, hcd);
+
 		retval = hcd->driver->pci_resume(hcd, hibernated);
 		if (retval) {
 			dev_err(dev, "PCI post-resume error %d!\n", retval);