]> pilppa.org Git - linux-2.6-omap-h63xx.git/blobdiff - drivers/usb/core/hub.c
USB: make hub driver's release more robust
[linux-2.6-omap-h63xx.git] / drivers / usb / core / hub.c
index f6b74a678de51f853e639c3fa7bcca80146021fd..77a6627b18d2da8e4422e5cdf241dab85939e937 100644 (file)
@@ -34,6 +34,7 @@
 struct usb_hub {
        struct device           *intfdev;       /* the "interface" device */
        struct usb_device       *hdev;
+       struct kref             kref;
        struct urb              *urb;           /* for interrupt polling pipe */
 
        /* buffer for urb ... with extra space in case of babble */
@@ -66,6 +67,7 @@ struct usb_hub {
        unsigned                limited_power:1;
        unsigned                quiescing:1;
        unsigned                activating:1;
+       unsigned                disconnected:1;
 
        unsigned                has_indicators:1;
        u8                      indicator[USB_MAXCHILDREN];
@@ -321,7 +323,7 @@ static void kick_khubd(struct usb_hub *hub)
        to_usb_interface(hub->intfdev)->pm_usage_cnt = 1;
 
        spin_lock_irqsave(&hub_event_lock, flags);
-       if (list_empty(&hub->event_list)) {
+       if (!hub->disconnected & list_empty(&hub->event_list)) {
                list_add_tail(&hub->event_list, &hub_event_list);
                wake_up(&khubd_wait);
        }
@@ -330,6 +332,7 @@ static void kick_khubd(struct usb_hub *hub)
 
 void usb_kick_khubd(struct usb_device *hdev)
 {
+       /* FIXME: What if hdev isn't bound to the hub driver? */
        kick_khubd(hdev_to_hub(hdev));
 }
 
@@ -845,43 +848,42 @@ fail:
        return ret;
 }
 
+static void hub_release(struct kref *kref)
+{
+       struct usb_hub *hub = container_of(kref, struct usb_hub, kref);
+
+       usb_put_intf(to_usb_interface(hub->intfdev));
+       kfree(hub);
+}
+
 static unsigned highspeed_hubs;
 
 static void hub_disconnect(struct usb_interface *intf)
 {
        struct usb_hub *hub = usb_get_intfdata (intf);
-       struct usb_device *hdev;
+
+       /* Take the hub off the event list and don't let it be added again */
+       spin_lock_irq(&hub_event_lock);
+       list_del_init(&hub->event_list);
+       hub->disconnected = 1;
+       spin_unlock_irq(&hub_event_lock);
 
        /* Disconnect all children and quiesce the hub */
        hub->error = 0;
        hub_pre_reset(intf);
 
        usb_set_intfdata (intf, NULL);
-       hdev = hub->hdev;
 
-       if (hdev->speed == USB_SPEED_HIGH)
+       if (hub->hdev->speed == USB_SPEED_HIGH)
                highspeed_hubs--;
 
        usb_free_urb(hub->urb);
-       hub->urb = NULL;
-
-       spin_lock_irq(&hub_event_lock);
-       list_del_init(&hub->event_list);
-       spin_unlock_irq(&hub_event_lock);
-
        kfree(hub->descriptor);
-       hub->descriptor = NULL;
-
        kfree(hub->status);
-       hub->status = NULL;
+       usb_buffer_free(hub->hdev, sizeof(*hub->buffer), hub->buffer,
+                       hub->buffer_dma);
 
-       if (hub->buffer) {
-               usb_buffer_free(hdev, sizeof(*hub->buffer), hub->buffer,
-                               hub->buffer_dma);
-               hub->buffer = NULL;
-       }
-
-       kfree(hub);
+       kref_put(&hub->kref, hub_release);
 }
 
 static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)
@@ -929,10 +931,12 @@ descriptor_error:
                return -ENOMEM;
        }
 
+       kref_init(&hub->kref);
        INIT_LIST_HEAD(&hub->event_list);
        hub->intfdev = &intf->dev;
        hub->hdev = hdev;
        INIT_DELAYED_WORK(&hub->leds, led_work);
+       usb_get_intf(intf);
 
        usb_set_intfdata (intf, hub);
        intf->needs_remote_wakeup = 1;
@@ -982,49 +986,6 @@ hub_ioctl(struct usb_interface *intf, unsigned int code, void *user_data)
 }
 
 
-/* grab device/port lock, returning index of that port (zero based).
- * protects the upstream link used by this device from concurrent
- * tree operations like suspend, resume, reset, and disconnect, which
- * apply to everything downstream of a given port.
- */
-static int locktree(struct usb_device *udev)
-{
-       int                     t;
-       struct usb_device       *hdev;
-
-       if (!udev)
-               return -ENODEV;
-
-       /* root hub is always the first lock in the series */
-       hdev = udev->parent;
-       if (!hdev) {
-               usb_lock_device(udev);
-               return 0;
-       }
-
-       /* on the path from root to us, lock everything from
-        * top down, dropping parent locks when not needed
-        */
-       t = locktree(hdev);
-       if (t < 0)
-               return t;
-
-       /* everything is fail-fast once disconnect
-        * processing starts
-        */
-       if (udev->state == USB_STATE_NOTATTACHED) {
-               usb_unlock_device(hdev);
-               return -ENODEV;
-       }
-
-       /* when everyone grabs locks top->bottom,
-        * non-overlapping work may be concurrent
-        */
-       usb_lock_device(udev);
-       usb_unlock_device(hdev);
-       return udev->portnum;
-}
-
 static void recursively_mark_NOTATTACHED(struct usb_device *udev)
 {
        int i;
@@ -1109,11 +1070,6 @@ void usb_root_hub_lost_power(struct usb_device *rhdev)
 
        dev_warn(&rhdev->dev, "root hub lost power or was reset\n");
 
-       /* Make sure no potential wakeup events get lost,
-        * by forcing the root hub to be resumed.
-        */
-       rhdev->dev.power.prev_state.event = PM_EVENT_ON;
-
        spin_lock_irqsave(&device_state_lock, flags);
        hub = hdev_to_hub(rhdev);
        for (port1 = 1; port1 <= rhdev->maxchild; ++port1) {
@@ -1158,6 +1114,30 @@ static void release_address(struct usb_device *udev)
        }
 }
 
+#ifdef CONFIG_USB_SUSPEND
+
+static void usb_stop_pm(struct usb_device *udev)
+{
+       /* Synchronize with the ksuspend thread to prevent any more
+        * autosuspend requests from being submitted, and decrement
+        * the parent's count of unsuspended children.
+        */
+       usb_pm_lock(udev);
+       if (udev->parent && !udev->discon_suspended)
+               usb_autosuspend_device(udev->parent);
+       usb_pm_unlock(udev);
+
+       /* Stop any autosuspend requests already submitted */
+       cancel_rearming_delayed_work(&udev->autosuspend);
+}
+
+#else
+
+static inline void usb_stop_pm(struct usb_device *udev)
+{ }
+
+#endif
+
 /**
  * usb_disconnect - disconnect a device (usbcore-internal)
  * @pdev: pointer to device being disconnected
@@ -1224,13 +1204,7 @@ void usb_disconnect(struct usb_device **pdev)
        *pdev = NULL;
        spin_unlock_irq(&device_state_lock);
 
-       /* Decrement the parent's count of unsuspended children */
-       if (udev->parent) {
-               usb_pm_lock(udev);
-               if (!udev->discon_suspended)
-                       usb_autosuspend_device(udev->parent);
-               usb_pm_unlock(udev);
-       }
+       usb_stop_pm(udev);
 
        put_device(&udev->dev);
 }
@@ -1903,7 +1877,6 @@ static int hub_suspend(struct usb_interface *intf, pm_message_t msg)
        struct usb_hub          *hub = usb_get_intfdata (intf);
        struct usb_device       *hdev = hub->hdev;
        unsigned                port1;
-       int                     status = 0;
 
        /* fail if children aren't already suspended */
        for (port1 = 1; port1 <= hdev->maxchild; port1++) {
@@ -1929,44 +1902,15 @@ static int hub_suspend(struct usb_interface *intf, pm_message_t msg)
 
        /* stop khubd and related activity */
        hub_quiesce(hub);
-
-       /* "global suspend" of the downstream HC-to-USB interface */
-       if (!hdev->parent) {
-               status = hcd_bus_suspend(hdev->bus);
-               if (status != 0) {
-                       dev_dbg(&hdev->dev, "'global' suspend %d\n", status);
-                       hub_activate(hub);
-               }
-       }
-       return status;
+       return 0;
 }
 
 static int hub_resume(struct usb_interface *intf)
 {
        struct usb_hub          *hub = usb_get_intfdata (intf);
-       struct usb_device       *hdev = hub->hdev;
-       int                     status;
 
        dev_dbg(&intf->dev, "%s\n", __FUNCTION__);
 
-       /* "global resume" of the downstream HC-to-USB interface */
-       if (!hdev->parent) {
-               struct usb_bus  *bus = hdev->bus;
-               if (bus) {
-                       status = hcd_bus_resume (bus);
-                       if (status) {
-                               dev_dbg(&intf->dev, "'global' resume %d\n",
-                                       status);
-                               return status;
-                       }
-               } else
-                       return -EOPNOTSUPP;
-               if (status == 0) {
-                       /* TRSMRCY = 10 msec */
-                       msleep(10);
-               }
-       }
-
        /* tell khubd to look for changes on this hub */
        hub_activate(hub);
        return 0;
@@ -2201,14 +2145,9 @@ hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1,
                                continue;
                        }
 
-                       /* Use a short timeout the first time through,
-                        * so that recalcitrant full-speed devices with
-                        * 8- or 16-byte ep0-maxpackets won't slow things
-                        * down tremendously by NAKing the unexpectedly
-                        * early status stage.  Also, retry on all errors;
-                        * some devices are flakey.
-                        * 255 is for WUSB devices, we actually need to use 512.
-                        * WUSB1.0[4.8.1].
+                       /* Retry on all errors; some devices are flakey.
+                        * 255 is for WUSB devices, we actually need to use
+                        * 512 (WUSB1.0[4.8.1]).
                         */
                        for (j = 0; j < 3; ++j) {
                                buf->bMaxPacketSize0 = 0;
@@ -2216,7 +2155,7 @@ hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1,
                                        USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
                                        USB_DT_DEVICE << 8, 0,
                                        buf, GET_DESCRIPTOR_BUFSIZE,
-                                       (i ? USB_CTRL_GET_TIMEOUT : 1000));
+                                       USB_CTRL_GET_TIMEOUT);
                                switch (buf->bMaxPacketSize0) {
                                case 8: case 16: case 32: case 64: case 255:
                                        if (buf->bDescriptorType ==
@@ -2426,10 +2365,10 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
 
        if (portchange & USB_PORT_STAT_C_CONNECTION) {
                status = hub_port_debounce(hub, port1);
-               if (status < 0 && printk_ratelimit()) {
-                       dev_err (hub_dev,
-                               "connect-debounce failed, port %d disabled\n",
-                               port1);
+               if (status < 0) {
+                       if (printk_ratelimit())
+                               dev_err (hub_dev, "connect-debounce failed, "
+                                               "port %d disabled\n", port1);
                        goto done;
                }
                portstatus = status;
@@ -2448,19 +2387,6 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
                return;
        }
 
-#ifdef  CONFIG_USB_SUSPEND
-       /* If something is connected, but the port is suspended, wake it up. */
-       if (portstatus & USB_PORT_STAT_SUSPEND) {
-               status = hub_port_resume(hub, port1, NULL);
-               if (status < 0) {
-                       dev_dbg(hub_dev,
-                               "can't clear suspend on port %d; %d\n",
-                               port1, status);
-                       goto done;
-               }
-       }
-#endif
-
        for (i = 0; i < SET_CONFIG_TRIES; i++) {
                struct usb_device *udev;
 
@@ -2612,10 +2538,12 @@ static void hub_events(void)
                list_del_init(tmp);
 
                hub = list_entry(tmp, struct usb_hub, event_list);
-               hdev = hub->hdev;
-               intf = to_usb_interface(hub->intfdev);
-               hub_dev = &intf->dev;
+               kref_get(&hub->kref);
+               spin_unlock_irq(&hub_event_lock);
 
+               hdev = hub->hdev;
+               hub_dev = hub->intfdev;
+               intf = to_usb_interface(hub_dev);
                dev_dbg(hub_dev, "state %d ports %d chg %04x evt %04x\n",
                                hdev->state, hub->descriptor
                                        ? hub->descriptor->bNbrPorts
@@ -2624,16 +2552,10 @@ static void hub_events(void)
                                (u16) hub->change_bits[0],
                                (u16) hub->event_bits[0]);
 
-               usb_get_intf(intf);
-               spin_unlock_irq(&hub_event_lock);
-
                /* Lock the device, then check to see if we were
                 * disconnected while waiting for the lock to succeed. */
-               if (locktree(hdev) < 0) {
-                       usb_put_intf(intf);
-                       continue;
-               }
-               if (hub != usb_get_intfdata(intf))
+               usb_lock_device(hdev);
+               if (unlikely(hub->disconnected))
                        goto loop;
 
                /* If the hub has died, clean up after it */
@@ -2796,7 +2718,7 @@ loop_autopm:
                        usb_autopm_enable(intf);
 loop:
                usb_unlock_device(hdev);
-               usb_put_intf(intf);
+               kref_put(&hub->kref, hub_release);
 
         } /* end while (1) */
 }