USB: add reset_resume method

This patch (as918) introduces a new USB driver method: reset_resume.
It is called when a device needs to be reset as part of a resume
procedure (whether because of a device quirk or because of the
USB-Persist facility), thereby taking over a role formerly assigned to
the post_reset method.  As a consequence, post_reset no longer needs
an argument indicating whether it is being called as part of a
reset-resume.  This separation of functions makes the code clearer.

In addition, the pre_reset and post_reset method return types are
changed; they now must return an error code.  The return value is
unused at present, but at some later time we may unbind drivers and
re-probe if they encounter an error during reset handling.

The existing pre_reset and post_reset methods in the usbhid,
usb-storage, and hub drivers are updated to match the new
requirements.  For usbhid the post_reset routine is also used for
reset_resume (duplicate method pointers); for the other drivers a new
reset_resume routine is added.  The change to hub.c looks bigger than
it really is, because mark_children_for_reset_resume() gets moved down
next to the new hub_reset_resume() routine.

A minor change to usb-storage makes the usb_stor_report_bus_reset()
routine acquire the host lock instead of requiring the caller to hold
it already.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
CC: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

6 files changed, 140 insertions, 80 deletions

diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c
index e221b0d1f667..b2baeaeba9be 100644
--- a/drivers/hid/usbhid/hid-core.c
+++ b/drivers/hid/usbhid/hid-core.c
@@ -1009,20 +1009,22 @@ static int hid_resume(struct usb_interface *intf)
 }
 
 /* Treat USB reset pretty much the same as suspend/resume */
-static void hid_pre_reset(struct usb_interface *intf)
+static int hid_pre_reset(struct usb_interface *intf)
 {
         /* FIXME: What if the interface is already suspended? */
         hid_suspend(intf, PMSG_ON);
+        return 0;
 }
 
-static void hid_post_reset(struct usb_interface *intf, int reset_resume)
+/* Same routine used for post_reset and reset_resume */
+static int hid_post_reset(struct usb_interface *intf)
 {
         struct usb_device *dev = interface_to_usbdev (intf);
 
         hid_set_idle(dev, intf->cur_altsetting->desc.bInterfaceNumber, 0, 0);
         /* FIXME: Any more reinitialization needed? */
 
-        hid_resume(intf);
+        return hid_resume(intf);
 }
 
 static struct usb_device_id hid_usb_ids [] = {
@@ -1039,6 +1041,7 @@ static struct usb_driver hid_driver = {
         .disconnect =   hid_disconnect,
         .suspend =      hid_suspend,
         .resume =       hid_resume,
+        .reset_resume = hid_post_reset,
         .pre_reset =    hid_pre_reset,
         .post_reset =   hid_post_reset,
         .id_table =     hid_usb_ids,
diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 6c62a6d91484..3cd9af2638fc 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -915,21 +915,37 @@ static int usb_resume_interface(struct usb_interface *intf, int reset_resume)
         }
         driver = to_usb_driver(intf->dev.driver);
 
-        if (reset_resume && driver->post_reset)
-                driver->post_reset(intf, reset_resume);
-        else if (driver->resume) {
-                status = driver->resume(intf);
-                if (status)
-                        dev_err(&intf->dev, "%s error %d\n",
-                                        "resume", status);
-        } else
-                dev_warn(&intf->dev, "no resume for driver %s?\n",
-                                driver->name);
+        if (reset_resume) {
+                if (driver->reset_resume) {
+                        status = driver->reset_resume(intf);
+                        if (status)
+                                dev_err(&intf->dev, "%s error %d\n",
+                                                "reset_resume", status);
+                } else {
+                        // status = -EOPNOTSUPP;
+                        dev_warn(&intf->dev, "no %s for driver %s?\n",
+                                        "reset_resume", driver->name);
+                }
+        } else {
+                if (driver->resume) {
+                        status = driver->resume(intf);
+                        if (status)
+                                dev_err(&intf->dev, "%s error %d\n",
+                                                "resume", status);
+                } else {
+                        // status = -EOPNOTSUPP;
+                        dev_warn(&intf->dev, "no %s for driver %s?\n",
+                                        "resume", driver->name);
+                }
+        }
 
 done:
         dev_vdbg(&intf->dev, "%s: status %d\n", __FUNCTION__, status);
         if (status == 0)
                 mark_active(intf);
+
+        /* FIXME: Unbind the driver and reprobe if the resume failed
+         * (not possible if auto_pm is set) */
         return status;
 }
 
@@ -966,6 +982,18 @@ static int autosuspend_check(struct usb_device *udev)
                                                 "for autosuspend\n");
                                 return -EOPNOTSUPP;
                         }
+
+                        /* Don't allow autosuspend if the device will need
+                         * a reset-resume and any of its interface drivers
+                         * doesn't include support.
+                         */
+                        if (udev->quirks & USB_QUIRK_RESET_RESUME) {
+                                struct usb_driver *driver;
+
+                                driver = to_usb_driver(intf->dev.driver);
+                                if (!driver->reset_resume)
+                                        return -EOPNOTSUPP;
+                        }
                 }
         }
 
@@ -1146,7 +1174,8 @@ static int usb_resume_both(struct usb_device *udev)
                         status = usb_autoresume_device(parent);
                         if (status == 0) {
                                 status = usb_resume_device(udev);
-                                if (status) {
+                                if (status || udev->state ==
+                                                USB_STATE_NOTATTACHED) {
                                         usb_autosuspend_device(parent);
 
                                         /* It's possible usb_resume_device()
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index ca3dbf84e800..0b8ed414d5cf 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -605,73 +605,26 @@ static void disconnect_all_children(struct usb_hub *hub, int logical)
         }
 }
 
-#ifdef  CONFIG_USB_PERSIST
-
-#define USB_PERSIST     1
-
-/* For "persistent-device" resets we must mark the child devices for reset
- * and turn off a possible connect-change status (so khubd won't disconnect
- * them later).
- */
-static void mark_children_for_reset_resume(struct usb_hub *hub)
-{
-        struct usb_device *hdev = hub->hdev;
-        int port1;
-
-        for (port1 = 1; port1 <= hdev->maxchild; ++port1) {
-                struct usb_device *child = hdev->children[port1-1];
-
-                if (child) {
-                        child->reset_resume = 1;
-                        clear_port_feature(hdev, port1,
-                                        USB_PORT_FEAT_C_CONNECTION);
-                }
-        }
-}
-
-#else
-
-#define USB_PERSIST     0
-
-static inline void mark_children_for_reset_resume(struct usb_hub *hub)
-{ }
-
-#endif  /* CONFIG_USB_PERSIST */
-
 /* caller has locked the hub device */
-static void hub_pre_reset(struct usb_interface *intf)
+static int hub_pre_reset(struct usb_interface *intf)
 {
         struct usb_hub *hub = usb_get_intfdata(intf);
 
-        /* This routine doesn't run as part of a reset-resume, so it's safe
-         * to disconnect all the drivers below the hub.
-         */
         disconnect_all_children(hub, 0);
         hub_quiesce(hub);
+        return 0;
 }
 
 /* caller has locked the hub device */
-static void hub_post_reset(struct usb_interface *intf, int reset_resume)
+static int hub_post_reset(struct usb_interface *intf)
 {
         struct usb_hub *hub = usb_get_intfdata(intf);
 
         hub_power_on(hub);
-        if (reset_resume) {
-                if (USB_PERSIST)
-                        mark_children_for_reset_resume(hub);
-                else {
-                        /* Reset-resume doesn't call pre_reset, so we have to
-                         * disconnect the children here.  But we may not lock
-                         * the child devices, so we have to do a "logical"
-                         * disconnect.
-                         */
-                        disconnect_all_children(hub, 1);
-                }
-        }
         hub_activate(hub);
+        return 0;
 }
 
-
 static int hub_configure(struct usb_hub *hub,
         struct usb_endpoint_descriptor *endpoint)
 {
@@ -1931,6 +1884,58 @@ static int hub_resume(struct usb_interface *intf)
         return 0;
 }
 
+#ifdef  CONFIG_USB_PERSIST
+
+#define USB_PERSIST     1
+
+/* For "persistent-device" resets we must mark the child devices for reset
+ * and turn off a possible connect-change status (so khubd won't disconnect
+ * them later).
+ */
+static void mark_children_for_reset_resume(struct usb_hub *hub)
+{
+        struct usb_device *hdev = hub->hdev;
+        int port1;
+
+        for (port1 = 1; port1 <= hdev->maxchild; ++port1) {
+                struct usb_device *child = hdev->children[port1-1];
+
+                if (child) {
+                        child->reset_resume = 1;
+                        clear_port_feature(hdev, port1,
+                                        USB_PORT_FEAT_C_CONNECTION);
+                }
+        }
+}
+
+#else
+
+#define USB_PERSIST     0
+
+static inline void mark_children_for_reset_resume(struct usb_hub *hub)
+{ }
+
+#endif  /* CONFIG_USB_PERSIST */
+
+static int hub_reset_resume(struct usb_interface *intf)
+{
+        struct usb_hub *hub = usb_get_intfdata(intf);
+
+        hub_power_on(hub);
+        if (USB_PERSIST)
+                mark_children_for_reset_resume(hub);
+        else {
+                /* Reset-resume doesn't call pre_reset, so we have to
+                 * disconnect the children here.  But we may not lock
+                 * the child devices, so we have to do a "logical"
+                 * disconnect.
+                 */
+                disconnect_all_children(hub, 1);
+        }
+        hub_activate(hub);
+        return 0;
+}
+
 #else   /* CONFIG_PM */
 
 static inline int remote_wakeup(struct usb_device *udev)
@@ -1938,8 +1943,9 @@ static inline int remote_wakeup(struct usb_device *udev)
         return 0;
 }
 
-#define hub_suspend NULL
-#define hub_resume NULL
+#define hub_suspend             NULL
+#define hub_resume              NULL
+#define hub_reset_resume        NULL
 #endif
 
 
@@ -2768,6 +2774,7 @@ static struct usb_driver hub_driver = {
         .disconnect =   hub_disconnect,
         .suspend =      hub_suspend,
         .resume =       hub_resume,
+        .reset_resume = hub_reset_resume,
         .pre_reset =    hub_pre_reset,
         .post_reset =   hub_post_reset,
         .ioctl =        hub_ioctl,
@@ -3021,6 +3028,7 @@ int usb_reset_composite_device(struct usb_device *udev,
                                 drv = to_usb_driver(cintf->dev.driver);
                                 if (drv->pre_reset)
                                         (drv->pre_reset)(cintf);
+        /* FIXME: Unbind if pre_reset returns an error or isn't defined */
                         }
                 }
         }
@@ -3038,7 +3046,8 @@ int usb_reset_composite_device(struct usb_device *udev,
                                         cintf->dev.driver) {
                                 drv = to_usb_driver(cintf->dev.driver);
                                 if (drv->post_reset)
-                                        (drv->post_reset)(cintf, 0);
+                                        (drv->post_reset)(cintf);
+        /* FIXME: Unbind if post_reset returns an error or isn't defined */
                         }
                         if (cintf != iface)
                                 up(&cintf->dev.sem);
diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c
index e227f64d5641..1ba19eaa1970 100644
--- a/drivers/usb/storage/scsiglue.c
+++ b/drivers/usb/storage/scsiglue.c
@@ -321,10 +321,14 @@ void usb_stor_report_device_reset(struct us_data *us)
 
 /* Report a driver-initiated bus reset to the SCSI layer.
  * Calling this for a SCSI-initiated reset is unnecessary but harmless.
- * The caller must own the SCSI host lock. */
+ * The caller must not own the SCSI host lock. */
 void usb_stor_report_bus_reset(struct us_data *us)
 {
-        scsi_report_bus_reset(us_to_host(us), 0);
+        struct Scsi_Host *host = us_to_host(us);
+
+        scsi_lock(host);
+        scsi_report_bus_reset(host, 0);
+        scsi_unlock(host);
 }
 
 /***********************************************************************
diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c
index be4cd8fe4ce6..00521f1d6a6b 100644
--- a/drivers/usb/storage/usb.c
+++ b/drivers/usb/storage/usb.c
@@ -219,6 +219,20 @@ static int storage_resume(struct usb_interface *iface)
         return 0;
 }
 
+static int storage_reset_resume(struct usb_interface *iface)
+{
+        struct us_data *us = usb_get_intfdata(iface);
+
+        US_DEBUGP("%s\n", __FUNCTION__);
+
+        /* Report the reset to the SCSI core */
+        usb_stor_report_bus_reset(us);
+
+        /* FIXME: Notify the subdrivers that they need to reinitialize
+         * the device */
+        return 0;
+}
+
 #endif /* CONFIG_PM */
 
 /*
@@ -226,7 +240,7 @@ static int storage_resume(struct usb_interface *iface)
  * a USB port reset, whether from this driver or a different one.
  */
 
-static void storage_pre_reset(struct usb_interface *iface)
+static int storage_pre_reset(struct usb_interface *iface)
 {
         struct us_data *us = usb_get_intfdata(iface);
 
@@ -234,26 +248,23 @@ static void storage_pre_reset(struct usb_interface *iface)
 
         /* Make sure no command runs during the reset */
         mutex_lock(&us->dev_mutex);
+        return 0;
 }
 
-static void storage_post_reset(struct usb_interface *iface, int reset_resume)
+static int storage_post_reset(struct usb_interface *iface)
 {
         struct us_data *us = usb_get_intfdata(iface);
 
         US_DEBUGP("%s\n", __FUNCTION__);
 
         /* Report the reset to the SCSI core */
-        scsi_lock(us_to_host(us));
         usb_stor_report_bus_reset(us);
-        scsi_unlock(us_to_host(us));
 
         /* FIXME: Notify the subdrivers that they need to reinitialize
          * the device */
 
-        /* If this is a reset-resume then the pre_reset routine wasn't
-         * called, so we don't need to unlock the mutex. */
-        if (!reset_resume)
-                mutex_unlock(&us->dev_mutex);
+        mutex_unlock(&us->dev_mutex);
+        return 0;
 }
 
 /*
@@ -1061,6 +1072,7 @@ static struct usb_driver usb_storage_driver = {
 #ifdef CONFIG_PM
         .suspend =      storage_suspend,
         .resume =       storage_resume,
+        .reset_resume = storage_reset_resume,
 #endif
         .pre_reset =    storage_pre_reset,
         .post_reset =   storage_post_reset,
diff --git a/include/linux/usb.h b/include/linux/usb.h
index 0873c6219efc..bde8c65e2bfc 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -839,6 +839,8 @@ struct usbdrv_wrap {
  *      do (or don't) show up otherwise in the filesystem.
  * @suspend: Called when the device is going to be suspended by the system.
  * @resume: Called when the device is being resumed by the system.
+ * @reset_resume: Called when the suspended device has been reset instead
+ *      of being resumed.
  * @pre_reset: Called by usb_reset_composite_device() when the device
  *      is about to be reset.
  * @post_reset: Called by usb_reset_composite_device() after the device
@@ -885,9 +887,10 @@ struct usb_driver {
 
         int (*suspend) (struct usb_interface *intf, pm_message_t message);
         int (*resume) (struct usb_interface *intf);
+        int (*reset_resume)(struct usb_interface *intf);
 
-        void (*pre_reset) (struct usb_interface *intf);
-        void (*post_reset) (struct usb_interface *intf, int reset_resume);
+        int (*pre_reset)(struct usb_interface *intf);
+        int (*post_reset)(struct usb_interface *intf);
 
         const struct usb_device_id *id_table;