3 files changed, 83 insertions, 18 deletions

diff --git a/drivers/usb/gadget/Makefile b/drivers/usb/gadget/Makefile
index 8b4acfd92aa3..fef41f5d6e8d 100644
--- a/drivers/usb/gadget/Makefile
+++ b/drivers/usb/gadget/Makefile
@@ -6,7 +6,7 @@ ccflags-$(CONFIG_USB_GADGET_DEBUG) := -DDEBUG
 obj-$(CONFIG_USB_GADGET)        += udc-core.o
 obj-$(CONFIG_USB_LIBCOMPOSITE)  += libcomposite.o
 libcomposite-y                  := usbstring.o config.o epautoconf.o
-libcomposite-y                  += composite.o
+libcomposite-y                  += composite.o functions.o
 obj-$(CONFIG_USB_DUMMY_HCD)     += dummy_hcd.o
 obj-$(CONFIG_USB_NET2272)       += net2272.o
 obj-$(CONFIG_USB_NET2280)       += net2280.o
diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 9db000013f5d..4aa0e4652228 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -683,6 +683,31 @@ done:
         return result;
 }
 
+int usb_add_config_only(struct usb_composite_dev *cdev,
+                struct usb_configuration *config)
+{
+        struct usb_configuration *c;
+
+        if (!config->bConfigurationValue)
+                return -EINVAL;
+
+        /* Prevent duplicate configuration identifiers */
+        list_for_each_entry(c, &cdev->configs, list) {
+                if (c->bConfigurationValue == config->bConfigurationValue)
+                        return -EBUSY;
+        }
+
+        config->cdev = cdev;
+        list_add_tail(&config->list, &cdev->configs);
+
+        INIT_LIST_HEAD(&config->functions);
+        config->next_interface_id = 0;
+        memset(config->interface, 0, sizeof(config->interface));
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(usb_add_config_only);
+
 /**
  * usb_add_config() - add a configuration to a device.
  * @cdev: wraps the USB gadget
@@ -703,30 +728,18 @@ int usb_add_config(struct usb_composite_dev *cdev,
                 int (*bind)(struct usb_configuration *))
 {
         int                             status = -EINVAL;
-        struct usb_configuration        *c;
+
+        if (!bind)
+                goto done;
 
         DBG(cdev, "adding config #%u '%s'/%p\n",
                         config->bConfigurationValue,
                         config->label, config);
 
-        if (!config->bConfigurationValue || !bind)
+        status = usb_add_config_only(cdev, config);
+        if (status)
                 goto done;
 
-        /* Prevent duplicate configuration identifiers */
-        list_for_each_entry(c, &cdev->configs, list) {
-                if (c->bConfigurationValue == config->bConfigurationValue) {
-                        status = -EBUSY;
-                        goto done;
-                }
-        }
-
-        config->cdev = cdev;
-        list_add_tail(&config->list, &cdev->configs);
-
-        INIT_LIST_HEAD(&config->functions);
-        config->next_interface_id = 0;
-        memset(config->interface, 0, sizeof(config->interface));
-
         status = bind(config);
         if (status < 0) {
                 while (!list_empty(&config->functions)) {
diff --git a/include/linux/usb/composite.h b/include/linux/usb/composite.h
index dc512c9432d7..3834e3330b23 100644
--- a/include/linux/usb/composite.h
+++ b/include/linux/usb/composite.h
@@ -77,6 +77,8 @@ struct usb_configuration;
  *      in interface or class descriptors; endpoints; I/O buffers; and so on.
  * @unbind: Reverses @bind; called as a side effect of unregistering the
  *      driver which added this function.
+ * @free_func: free the struct usb_function.
+ * @mod: (internal) points to the module that created this structure.
  * @set_alt: (REQUIRED) Reconfigures altsettings; function drivers may
  *      initialize usb_ep.driver data at this time (when it is used).
  *      Note that setting an interface to its current altsetting resets
@@ -116,6 +118,7 @@ struct usb_configuration;
  * two or more distinct instances within the same configuration, providing
  * several independent logical data links to a USB host.
  */
+
 struct usb_function {
         const char                      *name;
         struct usb_gadget_strings       **strings;
@@ -136,6 +139,8 @@ struct usb_function {
                                         struct usb_function *);
         void                    (*unbind)(struct usb_configuration *,
                                         struct usb_function *);
+        void                    (*free_func)(struct usb_function *f);
+        struct module           *mod;
 
         /* runtime state management */
         int                     (*set_alt)(struct usb_function *,
@@ -432,6 +437,53 @@ static inline u16 get_default_bcdDevice(void)
         return bcdDevice;
 }
 
+struct usb_function_driver {
+        const char *name;
+        struct module *mod;
+        struct list_head list;
+        struct usb_function_instance *(*alloc_inst)(void);
+        struct usb_function *(*alloc_func)(struct usb_function_instance *inst);
+};
+
+struct usb_function_instance {
+        struct usb_function_driver *fd;
+        void (*free_func_inst)(struct usb_function_instance *inst);
+};
+
+void usb_function_unregister(struct usb_function_driver *f);
+int usb_function_register(struct usb_function_driver *newf);
+void usb_put_function_instance(struct usb_function_instance *fi);
+void usb_put_function(struct usb_function *f);
+struct usb_function_instance *usb_get_function_instance(const char *name);
+struct usb_function *usb_get_function(struct usb_function_instance *fi);
+
+struct usb_configuration *usb_get_config(struct usb_composite_dev *cdev,
+                int val);
+int usb_add_config_only(struct usb_composite_dev *cdev,
+                struct usb_configuration *config);
+
+#define DECLARE_USB_FUNCTION(_name, _inst_alloc, _func_alloc)           \
+        static struct usb_function_driver _name ## usb_func = {         \
+                .name = __stringify(_name),                             \
+                .mod  = THIS_MODULE,                                    \
+                .alloc_inst = _inst_alloc,                              \
+                .alloc_func = _func_alloc,                              \
+        };                                                              \
+        MODULE_ALIAS("usbfunc:"__stringify(_name));
+
+#define DECLARE_USB_FUNCTION_INIT(_name, _inst_alloc, _func_alloc)      \
+        DECLARE_USB_FUNCTION(_name, _inst_alloc, _func_alloc)           \
+        static int __init _name ## mod_init(void)                       \
+        {                                                               \
+                return usb_function_register(&_name ## usb_func);       \
+        }                                                               \
+        static void __exit _name ## mod_exit(void)                      \
+        {                                                               \
+                usb_function_unregister(&_name ## usb_func);            \
+        }                                                               \
+        module_init(_name ## mod_init);                                 \
+        module_exit(_name ## mod_exit)
+
 /* messaging utils */
 #define DBG(d, fmt, args...) \
         dev_dbg(&(d)->gadget->dev , fmt , ## args)