1 files changed, 81 insertions, 10 deletions

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index d99963873e37..b97110ca352d 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -77,6 +77,7 @@ struct usb_hub {
         unsigned                has_indicators:1;
         u8                      indicator[USB_MAXCHILDREN];
         struct delayed_work     leds;
+        struct delayed_work     init_work;
 };
 
 
@@ -515,10 +516,14 @@ void usb_hub_tt_clear_buffer (struct usb_device *udev, int pipe)
 }
 EXPORT_SYMBOL_GPL(usb_hub_tt_clear_buffer);
 
-static void hub_power_on(struct usb_hub *hub)
+/* If do_delay is false, return the number of milliseconds the caller
+ * needs to delay.
+ */
+static unsigned hub_power_on(struct usb_hub *hub, bool do_delay)
 {
         int port1;
         unsigned pgood_delay = hub->descriptor->bPwrOn2PwrGood * 2;
+        unsigned delay;
         u16 wHubCharacteristics =
                         le16_to_cpu(hub->descriptor->wHubCharacteristics);
 
@@ -537,7 +542,10 @@ static void hub_power_on(struct usb_hub *hub)
                 set_port_feature(hub->hdev, port1, USB_PORT_FEAT_POWER);
 
         /* Wait at least 100 msec for power to become stable */
-        msleep(max(pgood_delay, (unsigned) 100));
+        delay = max(pgood_delay, (unsigned) 100);
+        if (do_delay)
+                msleep(delay);
+        return delay;
 }
 
 static int hub_hub_status(struct usb_hub *hub,
@@ -599,21 +607,55 @@ static void hub_port_logical_disconnect(struct usb_hub *hub, int port1)
 }
 
 enum hub_activation_type {
-        HUB_INIT, HUB_POST_RESET, HUB_RESUME, HUB_RESET_RESUME
+        HUB_INIT, HUB_INIT2, HUB_INIT3,
+        HUB_POST_RESET, HUB_RESUME, HUB_RESET_RESUME,
 };
 
+static void hub_init_func2(struct work_struct *ws);
+static void hub_init_func3(struct work_struct *ws);
+
 static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
 {
         struct usb_device *hdev = hub->hdev;
         int port1;
         int status;
         bool need_debounce_delay = false;
+        unsigned delay;
+
+        /* Continue a partial initialization */
+        if (type == HUB_INIT2)
+                goto init2;
+        if (type == HUB_INIT3)
+                goto init3;
 
         /* After a resume, port power should still be on.
          * For any other type of activation, turn it on.
          */
-        if (type != HUB_RESUME)
-                hub_power_on(hub);
+        if (type != HUB_RESUME) {
+
+                /* Speed up system boot by using a delayed_work for the
+                 * hub's initial power-up delays.  This is pretty awkward
+                 * and the implementation looks like a home-brewed sort of
+                 * setjmp/longjmp, but it saves at least 100 ms for each
+                 * root hub (assuming usbcore is compiled into the kernel
+                 * rather than as a module).  It adds up.
+                 *
+                 * This can't be done for HUB_RESUME or HUB_RESET_RESUME
+                 * because for those activation types the ports have to be
+                 * operational when we return.  In theory this could be done
+                 * for HUB_POST_RESET, but it's easier not to.
+                 */
+                if (type == HUB_INIT) {
+                        delay = hub_power_on(hub, false);
+                        PREPARE_DELAYED_WORK(&hub->init_work, hub_init_func2);
+                        schedule_delayed_work(&hub->init_work,
+                                        msecs_to_jiffies(delay));
+                        return;         /* Continues at init2: below */
+                } else {
+                        hub_power_on(hub, true);
+                }
+        }
+ init2:
 
         /* Check each port and set hub->change_bits to let khubd know
          * which ports need attention.
@@ -692,9 +734,20 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
          * If any port-status changes do occur during this delay, khubd
          * will see them later and handle them normally.
          */
-        if (need_debounce_delay)
-                msleep(HUB_DEBOUNCE_STABLE);
-
+        if (need_debounce_delay) {
+                delay = HUB_DEBOUNCE_STABLE;
+
+                /* Don't do a long sleep inside a workqueue routine */
+                if (type == HUB_INIT2) {
+                        PREPARE_DELAYED_WORK(&hub->init_work, hub_init_func3);
+                        schedule_delayed_work(&hub->init_work,
+                                        msecs_to_jiffies(delay));
+                        return;         /* Continues at init3: below */
+                } else {
+                        msleep(delay);
+                }
+        }
+ init3:
         hub->quiescing = 0;
 
         status = usb_submit_urb(hub->urb, GFP_NOIO);
@@ -707,6 +760,21 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
         kick_khubd(hub);
 }
 
+/* Implement the continuations for the delays above */
+static void hub_init_func2(struct work_struct *ws)
+{
+        struct usb_hub *hub = container_of(ws, struct usb_hub, init_work.work);
+
+        hub_activate(hub, HUB_INIT2);
+}
+
+static void hub_init_func3(struct work_struct *ws)
+{
+        struct usb_hub *hub = container_of(ws, struct usb_hub, init_work.work);
+
+        hub_activate(hub, HUB_INIT3);
+}
+
 enum hub_quiescing_type {
         HUB_DISCONNECT, HUB_PRE_RESET, HUB_SUSPEND
 };
@@ -716,6 +784,8 @@ static void hub_quiesce(struct usb_hub *hub, enum hub_quiescing_type type)
         struct usb_device *hdev = hub->hdev;
         int i;
 
+        cancel_delayed_work_sync(&hub->init_work);
+
         /* khubd and related activity won't re-trigger */
         hub->quiescing = 1;
 
@@ -1099,6 +1169,7 @@ descriptor_error:
         hub->intfdev = &intf->dev;
         hub->hdev = hdev;
         INIT_DELAYED_WORK(&hub->leds, led_work);
+        INIT_DELAYED_WORK(&hub->init_work, NULL);
         usb_get_intf(intf);
 
         usb_set_intfdata (intf, hub);
@@ -3035,7 +3106,7 @@ static void hub_events(void)
                                         i);
                                 clear_port_feature(hdev, i,
                                         USB_PORT_FEAT_C_OVER_CURRENT);
-                                hub_power_on(hub);
+                                hub_power_on(hub, true);
                         }
 
                         if (portchange & USB_PORT_STAT_C_RESET) {
@@ -3070,7 +3141,7 @@ static void hub_events(void)
                                 dev_dbg (hub_dev, "overcurrent change\n");
                                 msleep(500);    /* Cool down */
                                 clear_hub_feature(hdev, C_HUB_OVER_CURRENT);
-                                hub_power_on(hub);
+                                hub_power_on(hub, true);
                         }
                 }