Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 0062f6e5 authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Felipe Balbi
Browse files

usb: gadget: add a forward pointer from usb_function to its "instance" 



We can have multiple usb_functions which origin is the same "instance".
Within one USB configuration there should be only one function of an
instance. This back pointer helps configfs to recoginze to which
instance a given usb_function belongs.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarFelipe Balbi <balbi@ti.com>
parent 59835ad7

drivers/usb/gadget/functions.c

0 → 100644
+116 −0
Original line number Diff line number Diff line 
#include <linux/kernel.h>

#include <linux/slab.h>

#include <linux/module.h>

#include <linux/err.h>



#include <linux/usb/composite.h>



static LIST_HEAD(func_list);

static DEFINE_MUTEX(func_lock);



static struct usb_function_instance *try_get_usb_function_instance(const char *name)

{

	struct usb_function_driver *fd;

	struct usb_function_instance *fi;



	fi = ERR_PTR(-ENOENT);

	mutex_lock(&func_lock);

	list_for_each_entry(fd, &func_list, list) {



		if (strcmp(name, fd->name))

			continue;



		if (!try_module_get(fd->mod)) {

			fi = ERR_PTR(-EBUSY);

			break;

		}

		fi = fd->alloc_inst();

		if (IS_ERR(fi))

			module_put(fd->mod);

		else

			fi->fd = fd;

		break;

	}

	mutex_unlock(&func_lock);

	return fi;

}



struct usb_function_instance *usb_get_function_instance(const char *name)

{

	struct usb_function_instance *fi;

	int ret;



	fi = try_get_usb_function_instance(name);

	if (!IS_ERR(fi))

		return fi;

	ret = PTR_ERR(fi);

	if (ret != -ENOENT)

		return fi;

	ret = request_module("usbfunc:%s", name);

	if (ret < 0)

		return ERR_PTR(ret);

	return try_get_usb_function_instance(name);

}

EXPORT_SYMBOL_GPL(usb_get_function_instance);



struct usb_function *usb_get_function(struct usb_function_instance *fi)

{

	struct usb_function *f;



	f = fi->fd->alloc_func(fi);

	if (IS_ERR(f))

		return f;

	f->fi = fi;

	return f;

}

EXPORT_SYMBOL_GPL(usb_get_function);



void usb_put_function_instance(struct usb_function_instance *fi)

{

	struct module *mod;



	if (!fi)

		return;



	mod = fi->fd->mod;

	fi->free_func_inst(fi);

	module_put(mod);

}

EXPORT_SYMBOL_GPL(usb_put_function_instance);



void usb_put_function(struct usb_function *f)

{

	if (!f)

		return;



	f->free_func(f);

}

EXPORT_SYMBOL_GPL(usb_put_function);



int usb_function_register(struct usb_function_driver *newf)

{

	struct usb_function_driver *fd;

	int ret;



	ret = -EEXIST;



	mutex_lock(&func_lock);

	list_for_each_entry(fd, &func_list, list) {

		if (!strcmp(fd->name, newf->name))

			goto out;

	}

	ret = 0;

	list_add_tail(&newf->list, &func_list);

out:

	mutex_unlock(&func_lock);

	return ret;

}

EXPORT_SYMBOL_GPL(usb_function_register);



void usb_function_unregister(struct usb_function_driver *fd)

{

	mutex_lock(&func_lock);

	list_del(&fd->list);

	mutex_unlock(&func_lock);

}

EXPORT_SYMBOL_GPL(usb_function_unregister);

include/linux/usb/composite.h

+1 −0
Original line number Diff line number Diff line
@@ -161,6 +161,7 @@ struct usb_function { 
	/* internals */

	struct list_head		list;

	DECLARE_BITMAP(endpoints, 32);

	const struct usb_function_instance *fi;

};



int usb_add_function(struct usb_configuration *, struct usb_function *);