usbnet & cdc-ether: Autosuspend for online devices

Using remote wakeup and delayed transmission to allow
online device to go into usb autosuspend.
Minimal alternate support for devices that don't support
remote wakeup.

Signed-off-by: Oliver Neukum <oliver@neukum.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 136 insertions, 29 deletions

diff --git a/drivers/net/usb/cdc_ether.c b/drivers/net/usb/cdc_ether.c
index 197912d9c04..21e183a83b9 100644
--- a/drivers/net/usb/cdc_ether.c
+++ b/drivers/net/usb/cdc_ether.c
@@ -411,6 +411,12 @@ static int cdc_bind(struct usbnet *dev, struct usb_interface *intf)
         return 0;
 }
 
+static int cdc_manage_power(struct usbnet *dev, int on)
+{
+        dev->intf->needs_remote_wakeup = on;
+        return 0;
+}
+
 static const struct driver_info cdc_info = {
         .description =  "CDC Ethernet Device",
         .flags =        FLAG_ETHER | FLAG_LINK_INTR,
@@ -418,6 +424,7 @@ static const struct driver_info	cdc_info = {
         .bind =         cdc_bind,
         .unbind =       usbnet_cdc_unbind,
         .status =       cdc_status,
+        .manage_power = cdc_manage_power,
 };
 
 static const struct driver_info mbm_info = {
@@ -619,6 +626,7 @@ static struct usb_driver cdc_driver = {
         .suspend =      usbnet_suspend,
         .resume =       usbnet_resume,
         .reset_resume = usbnet_resume,
+        .supports_autosuspend = 1,
 };
 
 
diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 511e7bdc457..035fab04c0a 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -353,7 +353,8 @@ static void rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
 
         if (netif_running (dev->net) &&
             netif_device_present (dev->net) &&
-            !test_bit (EVENT_RX_HALT, &dev->flags)) {
+            !test_bit (EVENT_RX_HALT, &dev->flags) &&
+            !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
                 switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
                 case -EPIPE:
                         usbnet_defer_kevent (dev, EVENT_RX_HALT);
@@ -611,15 +612,39 @@ EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
 /*-------------------------------------------------------------------------*/
 
 // precondition: never called in_interrupt
+static void usbnet_terminate_urbs(struct usbnet *dev)
+{
+        DECLARE_WAIT_QUEUE_HEAD_ONSTACK(unlink_wakeup);
+        DECLARE_WAITQUEUE(wait, current);
+        int temp;
+
+        /* ensure there are no more active urbs */
+        add_wait_queue(&unlink_wakeup, &wait);
+        set_current_state(TASK_UNINTERRUPTIBLE);
+        dev->wait = &unlink_wakeup;
+        temp = unlink_urbs(dev, &dev->txq) +
+                unlink_urbs(dev, &dev->rxq);
+
+        /* maybe wait for deletions to finish. */
+        while (!skb_queue_empty(&dev->rxq)
+                && !skb_queue_empty(&dev->txq)
+                && !skb_queue_empty(&dev->done)) {
+                        schedule_timeout(UNLINK_TIMEOUT_MS);
+                        set_current_state(TASK_UNINTERRUPTIBLE);
+                        if (netif_msg_ifdown(dev))
+                                devdbg(dev, "waited for %d urb completions",
+                                        temp);
+        }
+        set_current_state(TASK_RUNNING);
+        dev->wait = NULL;
+        remove_wait_queue(&unlink_wakeup, &wait);
+}
 
 int usbnet_stop (struct net_device *net)
 {
         struct usbnet           *dev = netdev_priv(net);
         struct driver_info      *info = dev->driver_info;
-        int                     temp;
         int                     retval;
-        DECLARE_WAIT_QUEUE_HEAD_ONSTACK (unlink_wakeup);
-        DECLARE_WAITQUEUE (wait, current);
 
         netif_stop_queue (net);
 
@@ -641,25 +666,8 @@ int usbnet_stop (struct net_device *net)
                                 info->description);
         }
 
-        if (!(info->flags & FLAG_AVOID_UNLINK_URBS)) {
-                /* ensure there are no more active urbs */
-                add_wait_queue(&unlink_wakeup, &wait);
-                dev->wait = &unlink_wakeup;
-                temp = unlink_urbs(dev, &dev->txq) +
-                        unlink_urbs(dev, &dev->rxq);
-
-                /* maybe wait for deletions to finish. */
-                while (!skb_queue_empty(&dev->rxq) &&
-                       !skb_queue_empty(&dev->txq) &&
-                       !skb_queue_empty(&dev->done)) {
-                        msleep(UNLINK_TIMEOUT_MS);
-                        if (netif_msg_ifdown(dev))
-                                devdbg(dev, "waited for %d urb completions",
-                                        temp);
-                }
-                dev->wait = NULL;
-                remove_wait_queue(&unlink_wakeup, &wait);
-        }
+        if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
+                usbnet_terminate_urbs(dev);
 
         usb_kill_urb(dev->interrupt);
 
@@ -672,7 +680,10 @@ int usbnet_stop (struct net_device *net)
         dev->flags = 0;
         del_timer_sync (&dev->delay);
         tasklet_kill (&dev->bh);
-        usb_autopm_put_interface(dev->intf);
+        if (info->manage_power)
+                info->manage_power(dev, 0);
+        else
+                usb_autopm_put_interface(dev->intf);
 
         return 0;
 }
@@ -753,6 +764,12 @@ int usbnet_open (struct net_device *net)
 
         // delay posting reads until we're fully open
         tasklet_schedule (&dev->bh);
+        if (info->manage_power) {
+                retval = info->manage_power(dev, 1);
+                if (retval < 0)
+                        goto done;
+                usb_autopm_put_interface(dev->intf);
+        }
         return retval;
 done:
         usb_autopm_put_interface(dev->intf);
@@ -881,11 +898,16 @@ kevent (struct work_struct *work)
         /* usb_clear_halt() needs a thread context */
         if (test_bit (EVENT_TX_HALT, &dev->flags)) {
                 unlink_urbs (dev, &dev->txq);
+                status = usb_autopm_get_interface(dev->intf);
+                if (status < 0)
+                        goto fail_pipe;
                 status = usb_clear_halt (dev->udev, dev->out);
+                usb_autopm_put_interface(dev->intf);
                 if (status < 0 &&
                     status != -EPIPE &&
                     status != -ESHUTDOWN) {
                         if (netif_msg_tx_err (dev))
+fail_pipe:
                                 deverr (dev, "can't clear tx halt, status %d",
                                         status);
                 } else {
@@ -896,11 +918,16 @@ kevent (struct work_struct *work)
         }
         if (test_bit (EVENT_RX_HALT, &dev->flags)) {
                 unlink_urbs (dev, &dev->rxq);
+                status = usb_autopm_get_interface(dev->intf);
+                if (status < 0)
+                        goto fail_halt;
                 status = usb_clear_halt (dev->udev, dev->in);
+                usb_autopm_put_interface(dev->intf);
                 if (status < 0 &&
                     status != -EPIPE &&
                     status != -ESHUTDOWN) {
                         if (netif_msg_rx_err (dev))
+fail_halt:
                                 deverr (dev, "can't clear rx halt, status %d",
                                         status);
                 } else {
@@ -919,7 +946,12 @@ kevent (struct work_struct *work)
                         clear_bit (EVENT_RX_MEMORY, &dev->flags);
                 if (urb != NULL) {
                         clear_bit (EVENT_RX_MEMORY, &dev->flags);
+                        status = usb_autopm_get_interface(dev->intf);
+                        if (status < 0)
+                                goto fail_lowmem;
                         rx_submit (dev, urb, GFP_KERNEL);
+                        usb_autopm_put_interface(dev->intf);
+fail_lowmem:
                         tasklet_schedule (&dev->bh);
                 }
         }
@@ -929,11 +961,18 @@ kevent (struct work_struct *work)
                 int                     retval = 0;
 
                 clear_bit (EVENT_LINK_RESET, &dev->flags);
+                status = usb_autopm_get_interface(dev->intf);
+                if (status < 0)
+                        goto skip_reset;
                 if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
+                        usb_autopm_put_interface(dev->intf);
+skip_reset:
                         devinfo(dev, "link reset failed (%d) usbnet usb-%s-%s, %s",
                                 retval,
                                 dev->udev->bus->bus_name, dev->udev->devpath,
                                 info->description);
+                } else {
+                        usb_autopm_put_interface(dev->intf);
                 }
         }
 
@@ -971,6 +1010,7 @@ static void tx_complete (struct urb *urb)
                 case -EPROTO:
                 case -ETIME:
                 case -EILSEQ:
+                        usb_mark_last_busy(dev->udev);
                         if (!timer_pending (&dev->delay)) {
                                 mod_timer (&dev->delay,
                                         jiffies + THROTTLE_JIFFIES);
@@ -987,6 +1027,7 @@ static void tx_complete (struct urb *urb)
                 }
         }
 
+        usb_autopm_put_interface_async(dev->intf);
         urb->dev = NULL;
         entry->state = tx_done;
         defer_bh(dev, skb, &dev->txq);
@@ -1057,14 +1098,34 @@ netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
                 }
         }
 
-        spin_lock_irqsave (&dev->txq.lock, flags);
+        spin_lock_irqsave(&dev->txq.lock, flags);
+        retval = usb_autopm_get_interface_async(dev->intf);
+        if (retval < 0) {
+                spin_unlock_irqrestore(&dev->txq.lock, flags);
+                goto drop;
+        }
+
+#ifdef CONFIG_PM
+        /* if this triggers the device is still a sleep */
+        if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
+                /* transmission will be done in resume */
+                usb_anchor_urb(urb, &dev->deferred);
+                /* no use to process more packets */
+                netif_stop_queue(net);
+                spin_unlock_irqrestore(&dev->txq.lock, flags);
+                devdbg(dev, "Delaying transmission for resumption");
+                goto deferred;
+        }
+#endif
 
         switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
         case -EPIPE:
                 netif_stop_queue (net);
                 usbnet_defer_kevent (dev, EVENT_TX_HALT);
+                usb_autopm_put_interface_async(dev->intf);
                 break;
         default:
+                usb_autopm_put_interface_async(dev->intf);
                 if (netif_msg_tx_err (dev))
                         devdbg (dev, "tx: submit urb err %d", retval);
                 break;
@@ -1088,6 +1149,9 @@ drop:
                 devdbg (dev, "> tx, len %d, type 0x%x",
                         length, skb->protocol);
         }
+#ifdef CONFIG_PM
+deferred:
+#endif
         return NETDEV_TX_OK;
 }
 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
@@ -1263,6 +1327,7 @@ usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
         dev->bh.func = usbnet_bh;
         dev->bh.data = (unsigned long) dev;
         INIT_WORK (&dev->kevent, kevent);
+        init_usb_anchor(&dev->deferred);
         dev->delay.function = usbnet_bh;
         dev->delay.data = (unsigned long) dev;
         init_timer (&dev->delay);
@@ -1382,13 +1447,23 @@ int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
         struct usbnet           *dev = usb_get_intfdata(intf);
 
         if (!dev->suspend_count++) {
+                spin_lock_irq(&dev->txq.lock);
+                /* don't autosuspend while transmitting */
+                if (dev->txq.qlen && (message.event & PM_EVENT_AUTO)) {
+                        spin_unlock_irq(&dev->txq.lock);
+                        return -EBUSY;
+                } else {
+                        set_bit(EVENT_DEV_ASLEEP, &dev->flags);
+                        spin_unlock_irq(&dev->txq.lock);
+                }
                 /*
                  * accelerate emptying of the rx and queues, to avoid
                  * having everything error out.
                  */
                 netif_device_detach (dev->net);
-                (void) unlink_urbs (dev, &dev->rxq);
-                (void) unlink_urbs (dev, &dev->txq);
+                usbnet_terminate_urbs(dev);
+                usb_kill_urb(dev->interrupt);
+
                 /*
                  * reattach so runtime management can use and
                  * wake the device
@@ -1402,10 +1477,34 @@ EXPORT_SYMBOL_GPL(usbnet_suspend);
 int usbnet_resume (struct usb_interface *intf)
 {
         struct usbnet           *dev = usb_get_intfdata(intf);
+        struct sk_buff          *skb;
+        struct urb              *res;
+        int                     retval;
+
+        if (!--dev->suspend_count) {
+                spin_lock_irq(&dev->txq.lock);
+                while ((res = usb_get_from_anchor(&dev->deferred))) {
+
+                        printk(KERN_INFO"%s has delayed data\n", __func__);
+                        skb = (struct sk_buff *)res->context;
+                        retval = usb_submit_urb(res, GFP_ATOMIC);
+                        if (retval < 0) {
+                                dev_kfree_skb_any(skb);
+                                usb_free_urb(res);
+                                usb_autopm_put_interface_async(dev->intf);
+                        } else {
+                                dev->net->trans_start = jiffies;
+                                __skb_queue_tail(&dev->txq, skb);
+                        }
+                }
 
-        if (!--dev->suspend_count)
+                smp_mb();
+                clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
+                spin_unlock_irq(&dev->txq.lock);
+                if (!(dev->txq.qlen >= TX_QLEN(dev)))
+                        netif_start_queue(dev->net);
                 tasklet_schedule (&dev->bh);
-
+        }
         return 0;
 }
 EXPORT_SYMBOL_GPL(usbnet_resume);