[PATCH] root hub changes (lesser half)

This patch collects various small updates related to root hubs, to shrink
later patches which build on them.

  - For root hub suspend/resume support:
     * Make the existing usb_hcd_resume_root_hub() routine respect pmcore
       locking, exporting and using the dpm_runtime_resume() method.
     * Add a new usb_hcd_suspend_root_hub() to pair with that routine.
       (Essential to make OHCI autosuspend behave again...)
     * HC_SUSPENDED by itself only refers to the root hub's downstream ports.
       So let HCDs see root hub URBs unless the parent device is suspended.

  - Remove an assertion we no longer need (and now, also don't want).

  - Generic suspend/resume updates to work better with swsusp.
     * Ignore the FREEZE vs SUSPEND distinction for hardware; trying to
       use it breaks the swsusp snapshots it's supposed to help (sigh).
     * On resume, mark devices as resumed right away, but then
       do nothing else if the device is marked NOTATTACHED.

These changes shouldn't be very noticable by themselves.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

 drivers/base/power/runtime.c |    1
 drivers/usb/core/hcd.c       |   64 ++++++++++++++++++++++++++++++++++++++-----
 drivers/usb/core/hcd.h       |    1
 drivers/usb/core/hub.c       |   45 ++++++++++++++++++++++++------
 drivers/usb/core/usb.c       |   20 +++++++++----
 drivers/usb/core/usb.h       |    1
 6 files changed, 111 insertions(+), 21 deletions(-)

drivers/base/power/runtime.c

@@ -36,6 +36,7 @@ void dpm_runtime_resume(struct device * dev)
 	runtime_resume(dev);
 	up(&dpm_sem);
 }
+EXPORT_SYMBOL(dpm_runtime_resume);
 
 
 /**

drivers/usb/core/hcd.c

@@ -1143,10 +1143,20 @@ static int hcd_submit_urb (struct urb *urb, gfp_t mem_flags)
 	else switch (hcd->state) {
 	case HC_STATE_RUNNING:
 	case HC_STATE_RESUMING:
+doit:
 		usb_get_dev (urb->dev);
 		list_add_tail (&urb->urb_list, &ep->urb_list);
 		status = 0;
 		break;
+	case HC_STATE_SUSPENDED:
+		/* HC upstream links (register access, wakeup signaling) can work
+		 * even when the downstream links (and DMA etc) are quiesced; let
+		 * usbcore talk to the root hub.
+		 */
+		if (hcd->self.controller->power.power_state.event == PM_EVENT_ON
+				&& urb->dev->parent == NULL)
+			goto doit;
+		/* FALL THROUGH */
 	default:
 		status = -ESHUTDOWN;
 		break;
@@ -1294,12 +1304,6 @@ static int hcd_unlink_urb (struct urb *urb, int status)
 		goto done;
 	}
 
-	/* running ~= hc unlink handshake works (irq, timer, etc)
-	 * halted ~= no unlink handshake is needed
-	 * suspended, resuming == should never happen
-	 */
-	WARN_ON (!HC_IS_RUNNING (hcd->state) && hcd->state != HC_STATE_HALT);
-
 	/* insist the urb is still queued */
 	list_for_each(tmp, &ep->urb_list) {
 		if (tmp == &urb->urb_list)
@@ -1459,6 +1463,8 @@ static int hcd_hub_resume (struct usb_bus *bus)
 	hcd = container_of (bus, struct usb_hcd, self);
 	if (!hcd->driver->hub_resume)
 		return -ENOENT;
+	if (hcd->state == HC_STATE_RUNNING)
+		return 0;
 	hcd->state = HC_STATE_RESUMING;
 	status = hcd->driver->hub_resume (hcd);
 	if (status == 0)
@@ -1471,14 +1477,58 @@ static int hcd_hub_resume (struct usb_bus *bus)
 	return status;
 }
 
+/*
+ * usb_hcd_suspend_root_hub - HCD autosuspends downstream ports
+ * @hcd: host controller for this root hub
+ *
+ * This call arranges that usb_hcd_resume_root_hub() is safe to call later;
+ * that the HCD's root hub polling is deactivated; and that the root's hub
+ * driver is suspended.  HCDs may call this to autosuspend when their root
+ * hub's downstream ports are all inactive:  unpowered, disconnected,
+ * disabled, or suspended.
+ *
+ * The HCD will autoresume on device connect change detection (using SRP
+ * or a D+/D- pullup).  The HCD also autoresumes on remote wakeup signaling
+ * from any ports that are suspended (if that is enabled).  In most cases,
+ * overcurrent signaling (on powered ports) will also start autoresume.
+ *
+ * Always called with IRQs blocked.
+ */
+void usb_hcd_suspend_root_hub (struct usb_hcd *hcd)
+{
+	struct urb	*urb;
+
+	spin_lock (&hcd_root_hub_lock);
+	usb_suspend_root_hub (hcd->self.root_hub);
+
+	/* force status urb to complete/unlink while suspended */
+	if (hcd->status_urb) {
+		urb = hcd->status_urb;
+		urb->status = -ECONNRESET;
+		urb->hcpriv = NULL;
+		urb->actual_length = 0;
+
+		del_timer (&hcd->rh_timer);
+		hcd->poll_pending = 0;
+		hcd->status_urb = NULL;
+	} else
+		urb = NULL;
+	spin_unlock (&hcd_root_hub_lock);
+	hcd->state = HC_STATE_SUSPENDED;
+
+	if (urb)
+		usb_hcd_giveback_urb (hcd, urb, NULL);
+}
+EXPORT_SYMBOL_GPL(usb_hcd_suspend_root_hub);
+
 /**
  * usb_hcd_resume_root_hub - called by HCD to resume its root hub 
  * @hcd: host controller for this root hub
  *
  * The USB host controller calls this function when its root hub is
  * suspended (with the remote wakeup feature enabled) and a remote
  * wakeup request is received.  It queues a request for khubd to
- * resume the root hub.
+ * resume the root hub (that is, manage its downstream ports again).
  */
 void usb_hcd_resume_root_hub (struct usb_hcd *hcd)
 {

drivers/usb/core/hcd.h

@@ -355,6 +355,7 @@ extern long usb_calc_bus_time (int speed, int is_input,
 
 extern struct usb_bus *usb_alloc_bus (struct usb_operations *);
 
+extern void usb_hcd_suspend_root_hub (struct usb_hcd *hcd);
 extern void usb_hcd_resume_root_hub (struct usb_hcd *hcd);
 
 extern void usb_set_device_state(struct usb_device *udev,

drivers/usb/core/hub.c

@@ -449,11 +449,18 @@ static void hub_power_on(struct usb_hub *hub)
 	msleep(max(pgood_delay, (unsigned) 100));
 }
 
-static void hub_quiesce(struct usb_hub *hub)
+static inline void __hub_quiesce(struct usb_hub *hub)
 {
-	/* stop khubd and related activity */
+	/* (nonblocking) khubd and related activity won't re-trigger */
 	hub->quiescing = 1;
 	hub->activating = 0;
+	hub->resume_root_hub = 0;
+}
+
+static void hub_quiesce(struct usb_hub *hub)
+{
+	/* (blocking) stop khubd and related activity */
+	__hub_quiesce(hub);
 	usb_kill_urb(hub->urb);
 	if (hub->has_indicators)
 		cancel_delayed_work(&hub->leds);
@@ -467,6 +474,7 @@ static void hub_activate(struct usb_hub *hub)
 
 	hub->quiescing = 0;
 	hub->activating = 1;
+	hub->resume_root_hub = 0;
 	status = usb_submit_urb(hub->urb, GFP_NOIO);
 	if (status < 0)
 		dev_err(hub->intfdev, "activate --> %d\n", status);
@@ -1959,6 +1967,18 @@ static int hub_resume(struct usb_interface *intf)
 	return 0;
 }
 
+void usb_suspend_root_hub(struct usb_device *hdev)
+{
+	struct usb_hub *hub = hdev_to_hub(hdev);
+
+	/* This also makes any led blinker stop retriggering.  We're called
+	 * from irq, so the blinker might still be scheduled.  Caller promises
+	 * that the root hub status URB will be canceled.
+	 */
+	__hub_quiesce(hub);
+	mark_quiesced(to_usb_interface(hub->intfdev));
+}
+
 void usb_resume_root_hub(struct usb_device *hdev)
 {
 	struct usb_hub *hub = hdev_to_hub(hdev);
@@ -2616,21 +2636,30 @@ static void hub_events(void)
 		intf = to_usb_interface(hub->intfdev);
 		hub_dev = &intf->dev;
 
-		dev_dbg(hub_dev, "state %d ports %d chg %04x evt %04x\n",
+		i = hub->resume_root_hub;
+
+		dev_dbg(hub_dev, "state %d ports %d chg %04x evt %04x%s\n",
 				hdev->state, hub->descriptor
 					? hub->descriptor->bNbrPorts
 					: 0,
 				/* NOTE: expects max 15 ports... */
 				(u16) hub->change_bits[0],
-				(u16) hub->event_bits[0]);
+				(u16) hub->event_bits[0],
+				i ? ", resume root" : "");
 
 		usb_get_intf(intf);
-		i = hub->resume_root_hub;
 		spin_unlock_irq(&hub_event_lock);
 
-		/* Is this is a root hub wanting to be resumed? */
-		if (i)
-			usb_resume_device(hdev);
+		/* Is this is a root hub wanting to reactivate the downstream
+		 * ports?  If so, be sure the interface resumes even if its
+		 * stub "device" node was never suspended.
+		 */
+		if (i) {
+			extern void dpm_runtime_resume(struct device *);
+
+			dpm_runtime_resume(&hdev->dev);
+			dpm_runtime_resume(&intf->dev);
+		}
 
 		/* Lock the device, then check to see if we were
 		 * disconnected while waiting for the lock to succeed. */

drivers/usb/core/usb.c

@@ -1427,6 +1427,7 @@ static int usb_generic_suspend(struct device *dev, pm_message_t message)
 
 	/* USB devices enter SUSPEND state through their hubs, but can be
 	 * marked for FREEZE as soon as their children are already idled.
+	 * But those semantics are useless, so we equate the two (sigh).
 	 */
 	if (dev->driver == &usb_generic_driver) {
 		if (dev->power.power_state.event == message.event)
@@ -1435,10 +1436,6 @@ static int usb_generic_suspend(struct device *dev, pm_message_t message)
 		status = device_for_each_child(dev, NULL, verify_suspended);
 		if (status)
 			return status;
-		if (message.event == PM_EVENT_FREEZE) {
-			dev->power.power_state = message;
-			return 0;
-		}
  		return usb_suspend_device (to_usb_device(dev));
 	}
 
@@ -1471,14 +1468,22 @@ static int usb_generic_resume(struct device *dev)
 {
 	struct usb_interface	*intf;
 	struct usb_driver	*driver;
+	struct usb_device	*udev;
 	int			status;
 
 	if (dev->power.power_state.event == PM_EVENT_ON)
 		return 0;
 
+	/* mark things as "on" immediately, no matter what errors crop up */
+	dev->power.power_state.event = PM_EVENT_ON;
+
 	/* devices resume through their hubs */
-	if (dev->driver == &usb_generic_driver)
+	if (dev->driver == &usb_generic_driver) {
+		udev = to_usb_device(dev);
+		if (udev->state == USB_STATE_NOTATTACHED)
+			return 0;
 		return usb_resume_device (to_usb_device(dev));
+	}
 
 	if ((dev->driver == NULL) ||
 	    (dev->driver_data == &usb_generic_driver_data))
@@ -1487,11 +1492,14 @@ static int usb_generic_resume(struct device *dev)
 	intf = to_usb_interface(dev);
 	driver = to_usb_driver(dev->driver);
 
+	udev = interface_to_usbdev(intf);
+	if (udev->state == USB_STATE_NOTATTACHED)
+		return 0;
+
 	/* if driver was suspended, it has a resume method;
 	 * however, sysfs can wrongly mark things as suspended
 	 * (on the "no suspend method" FIXME path above)
 	 */
-	mark_active(intf);
 	if (driver->resume) {
 		status = driver->resume(intf);
 		if (status) {

drivers/usb/core/usb.h

@@ -19,6 +19,7 @@ extern void usb_lock_all_devices(void);
 extern void usb_unlock_all_devices(void);
 
 extern void usb_kick_khubd(struct usb_device *dev);
+extern void usb_suspend_root_hub(struct usb_device *hdev);
 extern void usb_resume_root_hub(struct usb_device *dev);
 
 extern int  usb_hub_init(void);