usb: gadget: add some infracture to register/unregister functions
This patch provides an infrastructure to register & unregister a USB
function. This allows to turn a function into a module and avoid the
'#include "f_.*.c"' magic and we get a clear API / cut between the bare
gadget and its functions.
The concept is simple:
Each function defines the DECLARE_USB_FUNCTION_INIT macro whith an unique
name of the function and two allocation functions.
- one to create an "instance". The instance holds the current configuration
set. In case there are two usb_configudations with one function there will
be one instance and two usb_functions
- one to create an "function" from the instance.
The name of the instance is used to automaticaly load the module if it the
instance is not yet available.
The usb_function callbacks are slightly modified and extended:
- usb_get_function()
creates a struct usb_function inclunding all pointers (bind,
unbind,…). It uses the "instance" to map its configuration. So we can
have _two_ struct usb_function, one for each usb_configuration.
- ->unbind()
Since the struct usb_function was not allocated in ->bind() it should
not kfree()d here. This function should only reverse what happens in
->bind() that is request cleanup and the cleanup of allocated
descriptors.
- ->free_func()
a simple kfree() of the struct usb_function
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/include/linux/usb/composite.h b/include/linux/usb/composite.h
index dc512c9..3834e33 100644
--- a/include/linux/usb/composite.h
+++ b/include/linux/usb/composite.h
@@ -77,6 +77,8 @@
* 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 @@
* 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 *);
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 @@
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)