USB: autosuspend for cdc-wdm

this patch implements

- suspend/resume
- aggressive autosuspend for the cdc-wdm driver
- pre/post_reset

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 101 insertions, 6 deletions

diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index 3a656f8f9935..1103ce7016b1 100644
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -88,6 +88,7 @@ struct wdm_device {
         dma_addr_t              ihandle;
         struct mutex            wlock;
         struct mutex            rlock;
+        struct mutex            plock;
         wait_queue_head_t       wait;
         struct work_struct      rxwork;
         int                     werr;
@@ -248,6 +249,7 @@ exit:
 
 static void kill_urbs(struct wdm_device *desc)
 {
+        /* the order here is essential */
         usb_kill_urb(desc->command);
         usb_kill_urb(desc->validity);
         usb_kill_urb(desc->response);
@@ -300,6 +302,9 @@ static ssize_t wdm_write
         if (r)
                 goto outnl;
 
+        r = usb_autopm_get_interface(desc->intf);
+        if (r < 0)
+                goto outnp;
         r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
                                                            &desc->flags));
         if (r < 0)
@@ -354,6 +359,8 @@ static ssize_t wdm_write
                         req->wIndex);
         }
 out:
+        usb_autopm_put_interface(desc->intf);
+outnp:
         mutex_unlock(&desc->wlock);
 outnl:
         return rv < 0 ? rv : count;
@@ -378,6 +385,11 @@ retry:
                 rv = wait_event_interruptible(desc->wait,
                                               test_bit(WDM_READ, &desc->flags));
 
+                if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
+                        rv = -ENODEV;
+                        goto err;
+                }
+                usb_mark_last_busy(interface_to_usbdev(desc->intf));
                 if (rv < 0) {
                         rv = -ERESTARTSYS;
                         goto err;
@@ -485,18 +497,28 @@ static int wdm_open(struct inode *inode, struct file *file)
         if (test_bit(WDM_DISCONNECTING, &desc->flags))
                 goto out;
 
-        desc->count++;
+        ;
         file->private_data = desc;
 
-        rv = usb_submit_urb(desc->validity, GFP_KERNEL);
-
+        rv = usb_autopm_get_interface(desc->intf);
         if (rv < 0) {
-                desc->count--;
-                err("Error submitting int urb - %d", rv);
+                err("Error autopm - %d", rv);
                 goto out;
         }
-        rv = 0;
+        intf->needs_remote_wakeup = 1;
 
+        mutex_lock(&desc->plock);
+        if (!desc->count++) {
+                rv = usb_submit_urb(desc->validity, GFP_KERNEL);
+                if (rv < 0) {
+                        desc->count--;
+                        err("Error submitting int urb - %d", rv);
+                }
+        } else {
+                rv = 0;
+        }
+        mutex_unlock(&desc->plock);
+        usb_autopm_put_interface(desc->intf);
 out:
         mutex_unlock(&wdm_mutex);
         return rv;
@@ -507,10 +529,15 @@ static int wdm_release(struct inode *inode, struct file *file)
         struct wdm_device *desc = file->private_data;
 
         mutex_lock(&wdm_mutex);
+        mutex_lock(&desc->plock);
         desc->count--;
+        mutex_unlock(&desc->plock);
+
         if (!desc->count) {
                 dev_dbg(&desc->intf->dev, "wdm_release: cleanup");
                 kill_urbs(desc);
+                if (!test_bit(WDM_DISCONNECTING, &desc->flags))
+                        desc->intf->needs_remote_wakeup = 0;
         }
         mutex_unlock(&wdm_mutex);
         return 0;
@@ -602,6 +629,7 @@ next_desc:
                 goto out;
         mutex_init(&desc->wlock);
         mutex_init(&desc->rlock);
+        mutex_init(&desc->plock);
         spin_lock_init(&desc->iuspin);
         init_waitqueue_head(&desc->wait);
         desc->wMaxCommand = maxcom;
@@ -703,6 +731,7 @@ static void wdm_disconnect(struct usb_interface *intf)
         spin_lock_irqsave(&desc->iuspin, flags);
         set_bit(WDM_DISCONNECTING, &desc->flags);
         set_bit(WDM_READ, &desc->flags);
+        /* to terminate pending flushes */
         clear_bit(WDM_IN_USE, &desc->flags);
         spin_unlock_irqrestore(&desc->iuspin, flags);
         cancel_work_sync(&desc->rxwork);
@@ -713,11 +742,77 @@ static void wdm_disconnect(struct usb_interface *intf)
         mutex_unlock(&wdm_mutex);
 }
 
+static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
+{
+        struct wdm_device *desc = usb_get_intfdata(intf);
+        int rv = 0;
+
+        dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
+
+        mutex_lock(&desc->plock);
+        if (interface_to_usbdev(desc->intf)->auto_pm && test_bit(WDM_IN_USE, &desc->flags)) {
+                rv = -EBUSY;
+        } else {
+                cancel_work_sync(&desc->rxwork);
+                kill_urbs(desc);
+        }
+        mutex_unlock(&desc->plock);
+
+        return rv;
+}
+
+static int recover_from_urb_loss(struct wdm_device *desc)
+{
+        int rv = 0;
+
+        if (desc->count) {
+                rv = usb_submit_urb(desc->validity, GFP_NOIO);
+                if (rv < 0)
+                        err("Error resume submitting int urb - %d", rv);
+        }
+        return rv;
+}
+static int wdm_resume(struct usb_interface *intf)
+{
+        struct wdm_device *desc = usb_get_intfdata(intf);
+        int rv;
+
+        dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
+        mutex_lock(&desc->plock);
+        rv = recover_from_urb_loss(desc);
+        mutex_unlock(&desc->plock);
+        return rv;
+}
+
+static int wdm_pre_reset(struct usb_interface *intf)
+{
+        struct wdm_device *desc = usb_get_intfdata(intf);
+
+        mutex_lock(&desc->plock);
+        return 0;
+}
+
+static int wdm_post_reset(struct usb_interface *intf)
+{
+        struct wdm_device *desc = usb_get_intfdata(intf);
+        int rv;
+
+        rv = recover_from_urb_loss(desc);
+        mutex_unlock(&desc->plock);
+        return 0;
+}
+
 static struct usb_driver wdm_driver = {
         .name =         "cdc_wdm",
         .probe =        wdm_probe,
         .disconnect =   wdm_disconnect,
+        .suspend =      wdm_suspend,
+        .resume =       wdm_resume,
+        .reset_resume = wdm_resume,
+        .pre_reset =    wdm_pre_reset,
+        .post_reset =   wdm_post_reset,
         .id_table =     wdm_ids,
+        .supports_autosuspend = 1,
 };
 
 /* --- low level module stuff --- */