usbcore: add usb_device_driver definition

This patch (as732) adds a usb_device_driver structure, for representing
drivers that manage an entire USB device as opposed to just an
interface.  Support routines like usb_register_device_driver,
usb_deregister_device_driver, usb_probe_device, and usb_unbind_device
are also added.

Unlike an earlier version of this patch, the new code is type-safe.  To
accomplish this, the existing struct driver embedded in struct
usb_driver had to be wrapped in an intermediate wrapper.  This enables
the core to tell at runtime whether a particular struct driver belongs
to a device driver or to an interface driver.


Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

5 files changed, 245 insertions, 84 deletions

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 8dcf2cd0c569..0d4b5dcee3ab 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -84,7 +84,7 @@ static int usb_create_newid_file(struct usb_driver *usb_drv)
                 goto exit;
 
         if (usb_drv->probe != NULL)
-                error = sysfs_create_file(&usb_drv->driver.kobj,
+                error = sysfs_create_file(&usb_drv->drvwrap.driver.kobj,
                                           &driver_attr_new_id.attr);
 exit:
         return error;
@@ -96,7 +96,7 @@ static void usb_remove_newid_file(struct usb_driver *usb_drv)
                 return;
 
         if (usb_drv->probe != NULL)
-                sysfs_remove_file(&usb_drv->driver.kobj,
+                sysfs_remove_file(&usb_drv->drvwrap.driver.kobj,
                                   &driver_attr_new_id.attr);
 }
 
@@ -143,18 +143,55 @@ static const struct usb_device_id *usb_match_dynamic_id(struct usb_interface *in
 }
 
 
-/* called from driver core with usb_bus_type.subsys writelock */
+/* called from driver core with dev locked */
+static int usb_probe_device(struct device *dev)
+{
+        struct usb_device_driver *udriver = to_usb_device_driver(dev->driver);
+        struct usb_device *udev;
+        int error = -ENODEV;
+
+        dev_dbg(dev, "%s\n", __FUNCTION__);
+
+        if (!is_usb_device(dev))        /* Sanity check */
+                return error;
+
+        udev = to_usb_device(dev);
+
+        /* FIXME: resume a suspended device */
+        if (udev->state == USB_STATE_SUSPENDED)
+                return -EHOSTUNREACH;
+
+        /* TODO: Add real matching code */
+
+        error = udriver->probe(udev);
+        return error;
+}
+
+/* called from driver core with dev locked */
+static int usb_unbind_device(struct device *dev)
+{
+        struct usb_device_driver *udriver = to_usb_device_driver(dev->driver);
+
+        udriver->disconnect(to_usb_device(dev));
+        return 0;
+}
+
+
+/* called from driver core with dev locked */
 static int usb_probe_interface(struct device *dev)
 {
-        struct usb_interface * intf = to_usb_interface(dev);
-        struct usb_driver * driver = to_usb_driver(dev->driver);
+        struct usb_driver *driver = to_usb_driver(dev->driver);
+        struct usb_interface *intf;
         const struct usb_device_id *id;
         int error = -ENODEV;
 
         dev_dbg(dev, "%s\n", __FUNCTION__);
 
-        if (!driver->probe)
+        if (is_usb_device(dev))         /* Sanity check */
                 return error;
+
+        intf = to_usb_interface(dev);
+
         /* FIXME we'd much prefer to just resume it ... */
         if (interface_to_usbdev(intf)->state == USB_STATE_SUSPENDED)
                 return -EHOSTUNREACH;
@@ -182,19 +219,18 @@ static int usb_probe_interface(struct device *dev)
         return error;
 }
 
-/* called from driver core with usb_bus_type.subsys writelock */
+/* called from driver core with dev locked */
 static int usb_unbind_interface(struct device *dev)
 {
+        struct usb_driver *driver = to_usb_driver(dev->driver);
         struct usb_interface *intf = to_usb_interface(dev);
-        struct usb_driver *driver = to_usb_driver(intf->dev.driver);
 
         intf->condition = USB_INTERFACE_UNBINDING;
 
         /* release all urbs for this interface */
         usb_disable_interface(interface_to_usbdev(intf), intf);
 
-        if (driver && driver->disconnect)
-                driver->disconnect(intf);
+        driver->disconnect(intf);
 
         /* reset other interface state */
         usb_set_interface(interface_to_usbdev(intf),
@@ -235,7 +271,7 @@ int usb_driver_claim_interface(struct usb_driver *driver,
         if (dev->driver)
                 return -EBUSY;
 
-        dev->driver = &driver->driver;
+        dev->driver = &driver->drvwrap.driver;
         usb_set_intfdata(iface, priv);
         iface->condition = USB_INTERFACE_BOUND;
         mark_active(iface);
@@ -270,7 +306,7 @@ void usb_driver_release_interface(struct usb_driver *driver,
         struct device *dev = &iface->dev;
 
         /* this should never happen, don't release something that's not ours */
-        if (!dev->driver || dev->driver != &driver->driver)
+        if (!dev->driver || dev->driver != &driver->drvwrap.driver)
                 return;
 
         /* don't release from within disconnect() */
@@ -433,24 +469,37 @@ EXPORT_SYMBOL_GPL_FUTURE(usb_match_id);
 
 int usb_device_match(struct device *dev, struct device_driver *drv)
 {
-        struct usb_interface *intf;
-        struct usb_driver *usb_drv;
-        const struct usb_device_id *id;
-
-        /* check for generic driver, which we don't match any device with */
-        if (drv == &usb_generic_driver)
-                return 0;
+        /* devices and interfaces are handled separately */
+        if (is_usb_device(dev)) {
 
-        intf = to_usb_interface(dev);
-        usb_drv = to_usb_driver(drv);
+                /* interface drivers never match devices */
+                if (!is_usb_device_driver(drv))
+                        return 0;
 
-        id = usb_match_id(intf, usb_drv->id_table);
-        if (id)
+                /* TODO: Add real matching code */
                 return 1;
 
-        id = usb_match_dynamic_id(intf, usb_drv);
-        if (id)
-                return 1;
+        } else {
+                struct usb_interface *intf;
+                struct usb_driver *usb_drv;
+                const struct usb_device_id *id;
+
+                /* device drivers never match interfaces */
+                if (is_usb_device_driver(drv))
+                        return 0;
+
+                intf = to_usb_interface(dev);
+                usb_drv = to_usb_driver(drv);
+
+                id = usb_match_id(intf, usb_drv->id_table);
+                if (id)
+                        return 1;
+
+                id = usb_match_dynamic_id(intf, usb_drv);
+                if (id)
+                        return 1;
+        }
+
         return 0;
 }
 
@@ -481,14 +530,13 @@ static int usb_uevent(struct device *dev, char **envp, int num_envp,
         /* driver is often null here; dev_dbg() would oops */
         pr_debug ("usb %s: uevent\n", dev->bus_id);
 
-        /* Must check driver_data here, as on remove driver is always NULL */
-        if ((dev->driver == &usb_generic_driver) ||
-            (dev->driver_data == &usb_generic_driver_data))
+        if (is_usb_device(dev))
                 return 0;
-
-        intf = to_usb_interface(dev);
-        usb_dev = interface_to_usbdev (intf);
-        alt = intf->cur_altsetting;
+        else {
+                intf = to_usb_interface(dev);
+                usb_dev = interface_to_usbdev(intf);
+                alt = intf->cur_altsetting;
+        }
 
         if (usb_dev->devnum < 0) {
                 pr_debug ("usb %s: already deleted?\n", dev->bus_id);
@@ -569,13 +617,71 @@ static int usb_uevent(struct device *dev, char **envp,
 #endif  /* CONFIG_HOTPLUG */
 
 /**
- * usb_register_driver - register a USB driver
- * @new_driver: USB operations for the driver
+ * usb_register_device_driver - register a USB device (not interface) driver
+ * @new_udriver: USB operations for the device driver
  * @owner: module owner of this driver.
  *
- * Registers a USB driver with the USB core.  The list of unattached
- * interfaces will be rescanned whenever a new driver is added, allowing
- * the new driver to attach to any recognized devices.
+ * Registers a USB device driver with the USB core.  The list of
+ * unattached devices will be rescanned whenever a new driver is
+ * added, allowing the new driver to attach to any recognized devices.
+ * Returns a negative error code on failure and 0 on success.
+ */
+int usb_register_device_driver(struct usb_device_driver *new_udriver,
+                struct module *owner)
+{
+        int retval = 0;
+
+        if (usb_disabled())
+                return -ENODEV;
+
+        new_udriver->drvwrap.for_devices = 1;
+        new_udriver->drvwrap.driver.name = (char *) new_udriver->name;
+        new_udriver->drvwrap.driver.bus = &usb_bus_type;
+        new_udriver->drvwrap.driver.probe = usb_probe_device;
+        new_udriver->drvwrap.driver.remove = usb_unbind_device;
+        new_udriver->drvwrap.driver.owner = owner;
+
+        retval = driver_register(&new_udriver->drvwrap.driver);
+
+        if (!retval) {
+                pr_info("%s: registered new device driver %s\n",
+                        usbcore_name, new_udriver->name);
+                usbfs_update_special();
+        } else {
+                printk(KERN_ERR "%s: error %d registering device "
+                        "       driver %s\n",
+                        usbcore_name, retval, new_udriver->name);
+        }
+
+        return retval;
+}
+EXPORT_SYMBOL_GPL(usb_register_device_driver);
+
+/**
+ * usb_deregister_device_driver - unregister a USB device (not interface) driver
+ * @udriver: USB operations of the device driver to unregister
+ * Context: must be able to sleep
+ *
+ * Unlinks the specified driver from the internal USB driver list.
+ */
+void usb_deregister_device_driver(struct usb_device_driver *udriver)
+{
+        pr_info("%s: deregistering device driver %s\n",
+                        usbcore_name, udriver->name);
+
+        driver_unregister(&udriver->drvwrap.driver);
+        usbfs_update_special();
+}
+EXPORT_SYMBOL_GPL(usb_deregister_device_driver);
+
+/**
+ * usb_register_driver - register a USB interface driver
+ * @new_driver: USB operations for the interface driver
+ * @owner: module owner of this driver.
+ *
+ * Registers a USB interface driver with the USB core.  The list of
+ * unattached interfaces will be rescanned whenever a new driver is
+ * added, allowing the new driver to attach to any recognized interfaces.
  * Returns a negative error code on failure and 0 on success.
  *
  * NOTE: if you want your driver to use the USB major number, you must call
@@ -589,23 +695,25 @@ int usb_register_driver(struct usb_driver *new_driver, struct module *owner)
         if (usb_disabled())
                 return -ENODEV;
 
-        new_driver->driver.name = (char *)new_driver->name;
-        new_driver->driver.bus = &usb_bus_type;
-        new_driver->driver.probe = usb_probe_interface;
-        new_driver->driver.remove = usb_unbind_interface;
-        new_driver->driver.owner = owner;
+        new_driver->drvwrap.for_devices = 0;
+        new_driver->drvwrap.driver.name = (char *) new_driver->name;
+        new_driver->drvwrap.driver.bus = &usb_bus_type;
+        new_driver->drvwrap.driver.probe = usb_probe_interface;
+        new_driver->drvwrap.driver.remove = usb_unbind_interface;
+        new_driver->drvwrap.driver.owner = owner;
         spin_lock_init(&new_driver->dynids.lock);
         INIT_LIST_HEAD(&new_driver->dynids.list);
 
-        retval = driver_register(&new_driver->driver);
+        retval = driver_register(&new_driver->drvwrap.driver);
 
         if (!retval) {
-                pr_info("%s: registered new driver %s\n",
+                pr_info("%s: registered new interface driver %s\n",
                         usbcore_name, new_driver->name);
                 usbfs_update_special();
                 usb_create_newid_file(new_driver);
         } else {
-                printk(KERN_ERR "%s: error %d registering driver %s\n",
+                printk(KERN_ERR "%s: error %d registering interface "
+                        "       driver %s\n",
                         usbcore_name, retval, new_driver->name);
         }
 
@@ -614,8 +722,8 @@ int usb_register_driver(struct usb_driver *new_driver, struct module *owner)
 EXPORT_SYMBOL_GPL_FUTURE(usb_register_driver);
 
 /**
- * usb_deregister - unregister a USB driver
- * @driver: USB operations of the driver to unregister
+ * usb_deregister - unregister a USB interface driver
+ * @driver: USB operations of the interface driver to unregister
  * Context: must be able to sleep
  *
  * Unlinks the specified driver from the internal USB driver list.
@@ -626,11 +734,12 @@ EXPORT_SYMBOL_GPL_FUTURE(usb_register_driver);
  */
 void usb_deregister(struct usb_driver *driver)
 {
-        pr_info("%s: deregistering driver %s\n", usbcore_name, driver->name);
+        pr_info("%s: deregistering interface driver %s\n",
+                        usbcore_name, driver->name);
 
         usb_remove_newid_file(driver);
         usb_free_dynids(driver);
-        driver_unregister(&driver->driver);
+        driver_unregister(&driver->drvwrap.driver);
 
         usbfs_update_special();
 }
@@ -655,7 +764,7 @@ static int usb_generic_suspend(struct device *dev, pm_message_t message)
          * marked for FREEZE as soon as their children are already idled.
          * But those semantics are useless, so we equate the two (sigh).
          */
-        if (dev->driver == &usb_generic_driver) {
+        if (is_usb_device(dev)) {
                 if (dev->power.power_state.event == message.event)
                         return 0;
                 /* we need to rule out bogus requests through sysfs */
@@ -665,8 +774,7 @@ static int usb_generic_suspend(struct device *dev, pm_message_t message)
                 return usb_port_suspend(to_usb_device(dev));
         }
 
-        if ((dev->driver == NULL) ||
-            (dev->driver_data == &usb_generic_driver_data))
+        if (dev->driver == NULL)
                 return 0;
 
         intf = to_usb_interface(dev);
@@ -705,15 +813,14 @@ static int usb_generic_resume(struct device *dev)
         dev->power.power_state.event = PM_EVENT_ON;
 
         /* devices resume through their hubs */
-        if (dev->driver == &usb_generic_driver) {
+        if (is_usb_device(dev)) {
                 udev = to_usb_device(dev);
                 if (udev->state == USB_STATE_NOTATTACHED)
                         return 0;
                 return usb_port_resume(udev);
         }
 
-        if ((dev->driver == NULL) ||
-            (dev->driver_data == &usb_generic_driver_data)) {
+        if (dev->driver == NULL) {
                 dev->power.power_state.event = PM_EVENT_FREEZE;
                 return 0;
         }
diff --git a/drivers/usb/core/generic.c b/drivers/usb/core/generic.c
index 7bab9769b34f..fa6f34a12b4b 100644
--- a/drivers/usb/core/generic.c
+++ b/drivers/usb/core/generic.c
@@ -21,14 +21,12 @@
 #include <linux/usb.h>
 #include "usb.h"
 
-static int generic_probe(struct device *dev)
+static int generic_probe(struct usb_device *udev)
 {
         return 0;
 }
-static int generic_remove(struct device *dev)
+static void generic_disconnect(struct usb_device *udev)
 {
-        struct usb_device *udev = to_usb_device(dev);
-
         /* if this is only an unbind, not a physical disconnect, then
          * unconfigure the device */
         if (udev->state == USB_STATE_CONFIGURED)
@@ -37,17 +35,10 @@ static int generic_remove(struct device *dev)
         /* in case the call failed or the device was suspended */
         if (udev->state >= USB_STATE_CONFIGURED)
                 usb_disable_device(udev, 0);
-        return 0;
 }
 
-struct device_driver usb_generic_driver = {
-        .owner = THIS_MODULE,
+struct usb_device_driver usb_generic_driver = {
         .name = "usb",
-        .bus = &usb_bus_type,
         .probe = generic_probe,
-        .remove = generic_remove,
+        .disconnect = generic_disconnect,
 };
-
-/* Fun hack to determine if the struct device is a
- * usb device or a usb interface. */
-int usb_generic_driver_data;
diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index 0b8c67bcde60..6dfbc284369b 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -123,7 +123,7 @@ static int __find_interface(struct device * dev, void * data)
         struct usb_interface *intf;
 
         /* can't look at usb devices, only interfaces */
-        if (dev->driver == &usb_generic_driver)
+        if (is_usb_device(dev))
                 return 0;
 
         intf = to_usb_interface(dev);
@@ -149,7 +149,8 @@ struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor)
 
         argb.minor = minor;
         argb.interface = NULL;
-        driver_for_each_device(&drv->driver, NULL, &argb, __find_interface);
+        driver_for_each_device(&drv->drvwrap.driver, NULL, &argb,
+                        __find_interface);
         return argb.interface;
 }
 
@@ -204,11 +205,13 @@ usb_alloc_dev(struct usb_device *parent, struct usb_bus *bus, unsigned port1)
         device_initialize(&dev->dev);
         dev->dev.bus = &usb_bus_type;
         dev->dev.dma_mask = bus->controller->dma_mask;
-        dev->dev.driver_data = &usb_generic_driver_data;
-        dev->dev.driver = &usb_generic_driver;
+        dev->dev.driver = &usb_generic_driver.drvwrap.driver;
         dev->dev.release = usb_release_dev;
         dev->state = USB_STATE_ATTACHED;
 
+        /* This magic assignment distinguishes devices from interfaces */
+        dev->dev.platform_data = &usb_generic_driver;
+
         INIT_LIST_HEAD(&dev->ep0.urb_list);
         dev->ep0.desc.bLength = USB_DT_ENDPOINT_SIZE;
         dev->ep0.desc.bDescriptorType = USB_DT_ENDPOINT;
@@ -838,7 +841,7 @@ static int __init usb_init(void)
         retval = usb_hub_init();
         if (retval)
                 goto hub_init_failed;
-        retval = driver_register(&usb_generic_driver);
+        retval = usb_register_device_driver(&usb_generic_driver, THIS_MODULE);
         if (!retval)
                 goto out;
 
@@ -868,7 +871,7 @@ static void __exit usb_exit(void)
         if (nousb)
                 return;
 
-        driver_unregister(&usb_generic_driver);
+        usb_deregister_device_driver(&usb_generic_driver);
         usb_major_cleanup();
         usbfs_cleanup();
         usb_deregister(&usbfs_driver);
diff --git a/drivers/usb/core/usb.h b/drivers/usb/core/usb.h
index 82d397a6f773..1d25ccac7832 100644
--- a/drivers/usb/core/usb.h
+++ b/drivers/usb/core/usb.h
@@ -34,8 +34,24 @@ extern int usb_port_suspend(struct usb_device *dev);
 extern int usb_port_resume(struct usb_device *dev);
 
 extern struct bus_type usb_bus_type;
-extern struct device_driver usb_generic_driver;
-extern int usb_generic_driver_data;
+extern struct usb_device_driver usb_generic_driver;
+
+/* Here's how we tell apart devices and interfaces.  Luckily there's
+ * no such thing as a platform USB device, so we can steal the use
+ * of the platform_data field. */
+
+static inline int is_usb_device(struct device *dev)
+{
+        return dev->platform_data == &usb_generic_driver;
+}
+
+/* Do the same for device drivers and interface drivers. */
+
+static inline int is_usb_device_driver(struct device_driver *drv)
+{
+        return container_of(drv, struct usbdrv_wrap, driver)->
+                        for_devices;
+}
 
 /* Interfaces and their "power state" are owned by usbcore */
 
diff --git a/include/linux/usb.h b/include/linux/usb.h
index d2bd0c8e0154..b4ccce6d0982 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -540,7 +540,17 @@ struct usb_dynids {
 };
 
 /**
- * struct usb_driver - identifies USB driver to usbcore
+ * struct usbdrv_wrap - wrapper for driver-model structure
+ * @driver: The driver-model core driver structure.
+ * @for_devices: Non-zero for device drivers, 0 for interface drivers.
+ */
+struct usbdrv_wrap {
+        struct device_driver driver;
+        int for_devices;
+};
+
+/**
+ * struct usb_driver - identifies USB interface driver to usbcore
  * @name: The driver name should be unique among USB drivers,
  *      and should normally be the same as the module name.
  * @probe: Called to see if the driver is willing to manage a particular
@@ -567,12 +577,12 @@ struct usb_dynids {
  *      or your driver's probe function will never get called.
  * @dynids: used internally to hold the list of dynamically added device
  *      ids for this driver.
- * @driver: the driver model core driver structure.
+ * @drvwrap: Driver-model core structure wrapper.
  * @no_dynamic_id: if set to 1, the USB core will not allow dynamic ids to be
  *      added to this driver by preventing the sysfs file from being created.
  *
- * USB drivers must provide a name, probe() and disconnect() methods,
- * and an id_table.  Other driver fields are optional.
+ * USB interface drivers must provide a name, probe() and disconnect()
+ * methods, and an id_table.  Other driver fields are optional.
  *
  * The id_table is used in hotplugging.  It holds a set of descriptors,
  * and specialized data may be associated with each entry.  That table
@@ -606,10 +616,40 @@ struct usb_driver {
         const struct usb_device_id *id_table;
 
         struct usb_dynids dynids;
-        struct device_driver driver;
+        struct usbdrv_wrap drvwrap;
         unsigned int no_dynamic_id:1;
 };
-#define to_usb_driver(d) container_of(d, struct usb_driver, driver)
+#define to_usb_driver(d) container_of(d, struct usb_driver, drvwrap.driver)
+
+/**
+ * struct usb_device_driver - identifies USB device driver to usbcore
+ * @name: The driver name should be unique among USB drivers,
+ *      and should normally be the same as the module name.
+ * @probe: Called to see if the driver is willing to manage a particular
+ *      device.  If it is, probe returns zero and uses dev_set_drvdata()
+ *      to associate driver-specific data with the device.  If unwilling
+ *      to manage the device, return a negative errno value.
+ * @disconnect: Called when the device is no longer accessible, usually
+ *      because it has been (or is being) disconnected or the driver's
+ *      module is being unloaded.
+ * @suspend: Called when the device is going to be suspended by the system.
+ * @resume: Called when the device is being resumed by the system.
+ * @drvwrap: Driver-model core structure wrapper.
+ *
+ * USB drivers must provide all the fields listed above except drvwrap.
+ */
+struct usb_device_driver {
+        const char *name;
+
+        int (*probe) (struct usb_device *udev);
+        void (*disconnect) (struct usb_device *udev);
+
+        int (*suspend) (struct usb_device *udev, pm_message_t message);
+        int (*resume) (struct usb_device *udev);
+        struct usbdrv_wrap drvwrap;
+};
+#define to_usb_device_driver(d) container_of(d, struct usb_device_driver, \
+                drvwrap.driver)
 
 extern struct bus_type usb_bus_type;
 
@@ -633,13 +673,17 @@ struct usb_class_driver {
  * use these in module_init()/module_exit()
  * and don't forget MODULE_DEVICE_TABLE(usb, ...)
  */
-int usb_register_driver(struct usb_driver *, struct module *);
+extern int usb_register_driver(struct usb_driver *, struct module *);
 static inline int usb_register(struct usb_driver *driver)
 {
         return usb_register_driver(driver, THIS_MODULE);
 }
 extern void usb_deregister(struct usb_driver *);
 
+extern int usb_register_device_driver(struct usb_device_driver *,
+                        struct module *);
+extern void usb_deregister_device_driver(struct usb_device_driver *);
+
 extern int usb_register_dev(struct usb_interface *intf,
                             struct usb_class_driver *class_driver);
 extern void usb_deregister_dev(struct usb_interface *intf,