1#include <linux/kernel.h>
  2#include <linux/slab.h>
  3#include <linux/module.h>
  4#include <linux/err.h>
  5
  6#include <linux/usb/composite.h>
  7
  8static LIST_HEAD(func_list);
  9static DEFINE_MUTEX(func_lock);
 10
 11static struct usb_function_instance *try_get_usb_function_instance(const char *name)
 12{
 13	struct usb_function_driver *fd;
 14	struct usb_function_instance *fi;
 15
 16	fi = ERR_PTR(-ENOENT);
 17	mutex_lock(&func_lock);
 18	list_for_each_entry(fd, &func_list, list) {
 19
 20		if (strcmp(name, fd->name))
 21			continue;
 22
 23		if (!try_module_get(fd->mod)) {
 24			fi = ERR_PTR(-EBUSY);
 25			break;
 26		}
 27		fi = fd->alloc_inst();
 28		if (IS_ERR(fi))
 29			module_put(fd->mod);
 30		else
 31			fi->fd = fd;
 32		break;
 33	}
 34	mutex_unlock(&func_lock);
 35	return fi;
 36}
 37
 38struct usb_function_instance *usb_get_function_instance(const char *name)
 39{
 40	struct usb_function_instance *fi;
 41	int ret;
 42
 43	fi = try_get_usb_function_instance(name);
 44	if (!IS_ERR(fi))
 45		return fi;
 46	ret = PTR_ERR(fi);
 47	if (ret != -ENOENT)
 48		return fi;
 49	ret = request_module("usbfunc:%s", name);
 50	if (ret < 0)
 51		return ERR_PTR(ret);
 52	return try_get_usb_function_instance(name);
 53}
 54EXPORT_SYMBOL_GPL(usb_get_function_instance);
 55
 56struct usb_function *usb_get_function(struct usb_function_instance *fi)
 57{
 58	struct usb_function *f;
 59
 60	f = fi->fd->alloc_func(fi);
 61	if (IS_ERR(f))
 62		return f;
 63	f->fi = fi;
 64	return f;
 65}
 66EXPORT_SYMBOL_GPL(usb_get_function);
 67
 68void usb_put_function_instance(struct usb_function_instance *fi)
 69{
 70	struct module *mod;
 71
 72	if (!fi)
 73		return;
 74
 75	mod = fi->fd->mod;
 76	fi->free_func_inst(fi);
 77	module_put(mod);
 78}
 79EXPORT_SYMBOL_GPL(usb_put_function_instance);
 80
 81void usb_put_function(struct usb_function *f)
 82{
 83	if (!f)
 84		return;
 85
 86	f->free_func(f);
 87}
 88EXPORT_SYMBOL_GPL(usb_put_function);
 89
 90int usb_function_register(struct usb_function_driver *newf)
 91{
 92	struct usb_function_driver *fd;
 93	int ret;
 94
 95	ret = -EEXIST;
 96
 97	mutex_lock(&func_lock);
 98	list_for_each_entry(fd, &func_list, list) {
 99		if (!strcmp(fd->name, newf->name))
100			goto out;
101	}
102	ret = 0;
103	list_add_tail(&newf->list, &func_list);
104out:
105	mutex_unlock(&func_lock);
106	return ret;
107}
108EXPORT_SYMBOL_GPL(usb_function_register);
109
110void usb_function_unregister(struct usb_function_driver *fd)
111{
112	mutex_lock(&func_lock);
113	list_del(&fd->list);
114	mutex_unlock(&func_lock);
115}
116EXPORT_SYMBOL_GPL(usb_function_unregister);