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

Thanks to Johannes Hölzl <johannes.hoelzl@gmx.de> 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 <gregkh@suse.de>
Signed-off-by: Johannes Hölzl <johannes.hoelzl@gmx.de>

3 files changed, 100 insertions, 21 deletions

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index d6eb5ce1dd1d..0c0c03a4e031 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -28,24 +28,16 @@
 #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;
@@ -65,9 +57,9 @@ static ssize_t store_new_id(struct device_driver *driver,
         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);
@@ -78,6 +70,15 @@ static ssize_t store_new_id(struct device_driver *driver,
                 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);
 
 static int usb_create_newid_file(struct usb_driver *usb_drv)
@@ -365,8 +366,8 @@ void usb_driver_release_interface(struct usb_driver *driver,
 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;
@@ -432,6 +433,8 @@ static int usb_match_one_id(struct usb_interface *interface,
 
         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
diff --git a/drivers/usb/serial/bus.c b/drivers/usb/serial/bus.c
index 6542f220468f..c08a38402b93 100644
--- a/drivers/usb/serial/bus.c
+++ b/drivers/usb/serial/bus.c
@@ -103,11 +103,52 @@ exit:
         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)
@@ -115,6 +156,9 @@ 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;
@@ -122,6 +166,7 @@ int usb_serial_bus_register(struct usb_serial_driver *driver)
 
 void usb_serial_bus_deregister(struct usb_serial_driver *driver)
 {
+        free_dynids(driver);
         driver_unregister(&driver->driver);
 }
 
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 716f6806cc89..90beb5c50e59 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -596,6 +596,39 @@ static struct usb_serial * create_serial (struct usb_device *dev,
         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;
@@ -605,11 +638,9 @@ static struct usb_serial_driver *search_serial_device(struct usb_interface *ifac
         /* 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;
@@ -661,7 +692,7 @@ int usb_serial_probe(struct usb_interface *interface,
                         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);