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);
117