Commit de53c254 authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Felipe Balbi
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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: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarFelipe Balbi <balbi@ti.com>
parent 78f46f09

drivers/usb/gadget/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -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

drivers/usb/gadget/composite.c

+30 −17
Original line number Diff line number Diff line
@@ -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
@@ -703,29 +728,17 @@ 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)

		goto done;



	/* Prevent duplicate configuration identifiers */

	list_for_each_entry(c, &cdev->configs, list) {

		if (c->bConfigurationValue == config->bConfigurationValue) {

			status = -EBUSY;

	status = usb_add_config_only(cdev, config);

	if (status)

		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) {

include/linux/usb/composite.h

+52 −0
Original line number Diff line number Diff line
@@ -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)

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