USB serial: add dynamic id support to usb-serial core

Thanks to Johannes Hölzl <[e-mail]> for fixing a few
things and getting it all working properly.

This adds support for dynamic usb ids to the usb serial core. The file
"new_id" will show up under the usb serial driver, not the usb driver
associated with the usb-serial driver (yeah, it can be a bit confusing
at first glance...)

This patch also modifies the USB core to allow the usb-serial core to
reuse much of the dynamic id logic.

Signed-off-by: Greg Kroah-Hartman <[e-mail]>
Signed-off-by: Johannes Hölzl <[e-mail]>

drivers/usb/core/driver.c

···
 #include "hcd.h"
 #include "usb.h"
 
-static int usb_match_one_id(struct usb_interface *interface,
-			    const struct usb_device_id *id);
-
-struct usb_dynid {
-	struct list_head node;
-	struct usb_device_id id;
-};
-
 #ifdef CONFIG_HOTPLUG
 
 /*
  * Adds a new dynamic USBdevice ID to this driver,
  * and cause the driver to probe for all devices again.
  */
-static ssize_t store_new_id(struct device_driver *driver,
-			    const char *buf, size_t count)
+ssize_t usb_store_new_id(struct usb_dynids *dynids,
+			 struct device_driver *driver,
+			 const char *buf, size_t count)
 {
-	struct usb_driver *usb_drv = to_usb_driver(driver);
 	struct usb_dynid *dynid;
 	u32 idVendor = 0;
 	u32 idProduct = 0;
···
 	dynid->id.idProduct = idProduct;
 	dynid->id.match_flags = USB_DEVICE_ID_MATCH_DEVICE;
 
-	spin_lock(&usb_drv->dynids.lock);
-	list_add_tail(&usb_drv->dynids.list, &dynid->node);
-	spin_unlock(&usb_drv->dynids.lock);
+	spin_lock(&dynids->lock);
+	list_add_tail(&dynids->list, &dynid->node);
+	spin_unlock(&dynids->lock);
 
 	if (get_driver(driver)) {
 		retval = driver_attach(driver);
···
 	if (retval)
 		return retval;
 	return count;
+}
+EXPORT_SYMBOL_GPL(usb_store_new_id);
+
+static ssize_t store_new_id(struct device_driver *driver,
+			    const char *buf, size_t count)
+{
+	struct usb_driver *usb_drv = to_usb_driver(driver);
+
+	return usb_store_new_id(&usb_drv->dynids, driver, buf, count);
 }
 static DRIVER_ATTR(new_id, S_IWUSR, NULL, store_new_id);
 
···
 EXPORT_SYMBOL(usb_driver_release_interface);
 
 /* returns 0 if no match, 1 if match */
-static int usb_match_one_id(struct usb_interface *interface,
-			    const struct usb_device_id *id)
+int usb_match_one_id(struct usb_interface *interface,
+		     const struct usb_device_id *id)
 {
 	struct usb_host_interface *intf;
 	struct usb_device *dev;
···
 
 	return 1;
 }
+EXPORT_SYMBOL_GPL(usb_match_one_id);
+
 /**
  * usb_match_id - find first usb_device_id matching device or interface
  * @interface: the interface of interest

drivers/usb/serial/bus.c

···
 	return retval;
 }
 
+#ifdef CONFIG_HOTPLUG
+static ssize_t store_new_id(struct device_driver *driver,
+			    const char *buf, size_t count)
+{
+	struct usb_serial_driver *usb_drv = to_usb_serial_driver(driver);
+	ssize_t retval = usb_store_new_id(&usb_drv->dynids, driver, buf, count);
+
+	if (retval >= 0 && usb_drv->usb_driver != NULL)
+		retval = usb_store_new_id(&usb_drv->usb_driver->dynids,
+					  &usb_drv->usb_driver->drvwrap.driver,
+					  buf, count);
+	return retval;
+}
+
+static struct driver_attribute drv_attrs[] = {
+	__ATTR(new_id, S_IWUSR, NULL, store_new_id),
+	__ATTR_NULL,
+};
+
+static void free_dynids(struct usb_serial_driver *drv)
+{
+	struct usb_dynid *dynid, *n;
+
+	spin_lock(&drv->dynids.lock);
+	list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
+		list_del(&dynid->node);
+		kfree(dynid);
+	}
+	spin_unlock(&drv->dynids.lock);
+}
+
+#else
+static struct driver_attribute drv_attrs[] = {
+	__ATTR_NULL,
+};
+static inline void free_dynids(struct usb_driver *drv)
+{
+}
+#endif
+
 struct bus_type usb_serial_bus_type = {
 	.name =		"usb-serial",
 	.match =	usb_serial_device_match,
 	.probe =	usb_serial_device_probe,
 	.remove =	usb_serial_device_remove,
+	.drv_attrs = 	drv_attrs,
 };
 
 int usb_serial_bus_register(struct usb_serial_driver *driver)
···
 	int retval;
 
 	driver->driver.bus = &usb_serial_bus_type;
+	spin_lock_init(&driver->dynids.lock);
+	INIT_LIST_HEAD(&driver->dynids.list);
+
 	retval = driver_register(&driver->driver);
 
 	return retval;
···
 
 void usb_serial_bus_deregister(struct usb_serial_driver *driver)
 {
+	free_dynids(driver);
 	driver_unregister(&driver->driver);
 }
 

drivers/usb/serial/usb-serial.c

···
 	return serial;
 }
 
+static const struct usb_device_id *match_dynamic_id(struct usb_interface *intf,
+						    struct usb_serial_driver *drv)
+{
+	struct usb_dynid *dynid;
+
+	spin_lock(&drv->dynids.lock);
+	list_for_each_entry(dynid, &drv->dynids.list, node) {
+		if (usb_match_one_id(intf, &dynid->id)) {
+			spin_unlock(&drv->dynids.lock);
+			return &dynid->id;
+		}
+	}
+	spin_unlock(&drv->dynids.lock);
+	return NULL;
+}
+
+static const struct usb_device_id *get_iface_id(struct usb_serial_driver *drv,
+						struct usb_interface *intf)
+{
+	const struct usb_device_id *id;
+
+	id = usb_match_id(intf, drv->id_table);
+	if (id) {
+		dbg("static descriptor matches");
+		goto exit;
+	}
+	id = match_dynamic_id(intf, drv);
+	if (id)
+		dbg("dynamic descriptor matches");
+exit:
+	return id;
+}
+
 static struct usb_serial_driver *search_serial_device(struct usb_interface *iface)
 {
 	struct list_head *p;
···
 	/* Check if the usb id matches a known device */
 	list_for_each(p, &usb_serial_driver_list) {
 		t = list_entry(p, struct usb_serial_driver, driver_list);
-		id = usb_match_id(iface, t->id_table);
-		if (id != NULL) {
-			dbg("descriptor matches");
+		id = get_iface_id(t, iface);
+		if (id)
 			return t;
-		}
 	}
 
 	return NULL;
···
 			return -EIO;
 		}
 
-		id = usb_match_id(interface, type->id_table);
+		id = get_iface_id(type, interface);
 		retval = type->probe(serial, id);
 		module_put(type->driver.owner);
 

include/linux/usb.h

···
 			struct usb_interface *iface);
 const struct usb_device_id *usb_match_id(struct usb_interface *interface,
 					 const struct usb_device_id *id);
+extern int usb_match_one_id(struct usb_interface *interface,
+			    const struct usb_device_id *id);
 
 extern struct usb_interface *usb_find_interface(struct usb_driver *drv,
 		int minor);
···
 
 /* ----------------------------------------------------------------------- */
 
+/* Stuff for dynamic usb ids */
 struct usb_dynids {
 	spinlock_t lock;
 	struct list_head list;
 };
+
+struct usb_dynid {
+	struct list_head node;
+	struct usb_device_id id;
+};
+
+extern ssize_t usb_store_new_id(struct usb_dynids *dynids,
+				struct device_driver *driver,
+				const char *buf, size_t count);
 
 /**
  * struct usbdrv_wrap - wrapper for driver-model structure

include/linux/usb/serial.h

···
  *	memory structure allocation at this point in time.
  * @shutdown: pointer to the driver's shutdown function.  This will be
  *	called when the device is removed from the system.
+ * @usb_driver: pointer to the struct usb_driver that controls this
+ *	device.  This is necessary to allow dynamic ids to be added to
+ *	the driver from sysfs.
  *
  * This structure is defines a USB Serial driver.  It provides all of
  * the information that the USB serial core code needs.  If the function
···
 
 	struct list_head	driver_list;
 	struct device_driver	driver;
+	struct usb_driver	*usb_driver;
+	struct usb_dynids	dynids;
 
 	int (*probe) (struct usb_serial *serial, const struct usb_device_id *id);
 	int (*attach) (struct usb_serial *serial);