| 1 | // SPDX-License-Identifier: GPL-2.0 |
|---|---|
| 2 | #include <linux/kernel.h> |
| 3 | #include <linux/slab.h> |
| 4 | #include <linux/module.h> |
| 5 | #include <linux/err.h> |
| 6 | |
| 7 | #include <linux/usb/composite.h> |
| 8 | |
| 9 | static LIST_HEAD(func_list); |
| 10 | static DEFINE_MUTEX(func_lock); |
| 11 | |
| 12 | static struct usb_function_instance *try_get_usb_function_instance(const char *name) |
| 13 | { |
| 14 | struct usb_function_driver *fd; |
| 15 | struct usb_function_instance *fi; |
| 16 | |
| 17 | fi = ERR_PTR(error: -ENOENT); |
| 18 | mutex_lock(&func_lock); |
| 19 | list_for_each_entry(fd, &func_list, list) { |
| 20 | |
| 21 | if (strcmp(name, fd->name)) |
| 22 | continue; |
| 23 | |
| 24 | if (!try_module_get(module: fd->mod)) { |
| 25 | fi = ERR_PTR(error: -EBUSY); |
| 26 | break; |
| 27 | } |
| 28 | fi = fd->alloc_inst(); |
| 29 | if (IS_ERR(ptr: fi)) |
| 30 | module_put(module: fd->mod); |
| 31 | else |
| 32 | fi->fd = fd; |
| 33 | break; |
| 34 | } |
| 35 | mutex_unlock(lock: &func_lock); |
| 36 | return fi; |
| 37 | } |
| 38 | |
| 39 | struct usb_function_instance *usb_get_function_instance(const char *name) |
| 40 | { |
| 41 | struct usb_function_instance *fi; |
| 42 | int ret; |
| 43 | |
| 44 | fi = try_get_usb_function_instance(name); |
| 45 | if (!IS_ERR(ptr: fi)) |
| 46 | return fi; |
| 47 | ret = PTR_ERR(ptr: fi); |
| 48 | if (ret != -ENOENT) |
| 49 | return fi; |
| 50 | ret = request_module("usbfunc:%s", name); |
| 51 | if (ret < 0) |
| 52 | return ERR_PTR(error: ret); |
| 53 | return try_get_usb_function_instance(name); |
| 54 | } |
| 55 | EXPORT_SYMBOL_GPL(usb_get_function_instance); |
| 56 | |
| 57 | struct usb_function *usb_get_function(struct usb_function_instance *fi) |
| 58 | { |
| 59 | struct usb_function *f; |
| 60 | |
| 61 | f = fi->fd->alloc_func(fi); |
| 62 | if (IS_ERR(ptr: f)) |
| 63 | return f; |
| 64 | f->fi = fi; |
| 65 | return f; |
| 66 | } |
| 67 | EXPORT_SYMBOL_GPL(usb_get_function); |
| 68 | |
| 69 | void usb_put_function_instance(struct usb_function_instance *fi) |
| 70 | { |
| 71 | struct module *mod; |
| 72 | |
| 73 | if (!fi) |
| 74 | return; |
| 75 | |
| 76 | mod = fi->fd->mod; |
| 77 | fi->free_func_inst(fi); |
| 78 | module_put(module: mod); |
| 79 | } |
| 80 | EXPORT_SYMBOL_GPL(usb_put_function_instance); |
| 81 | |
| 82 | void usb_put_function(struct usb_function *f) |
| 83 | { |
| 84 | if (!f) |
| 85 | return; |
| 86 | |
| 87 | f->free_func(f); |
| 88 | } |
| 89 | EXPORT_SYMBOL_GPL(usb_put_function); |
| 90 | |
| 91 | int usb_function_register(struct usb_function_driver *newf) |
| 92 | { |
| 93 | struct usb_function_driver *fd; |
| 94 | int ret; |
| 95 | |
| 96 | ret = -EEXIST; |
| 97 | |
| 98 | mutex_lock(&func_lock); |
| 99 | list_for_each_entry(fd, &func_list, list) { |
| 100 | if (!strcmp(fd->name, newf->name)) |
| 101 | goto out; |
| 102 | } |
| 103 | ret = 0; |
| 104 | list_add_tail(new: &newf->list, head: &func_list); |
| 105 | out: |
| 106 | mutex_unlock(lock: &func_lock); |
| 107 | return ret; |
| 108 | } |
| 109 | EXPORT_SYMBOL_GPL(usb_function_register); |
| 110 | |
| 111 | void usb_function_unregister(struct usb_function_driver *fd) |
| 112 | { |
| 113 | mutex_lock(&func_lock); |
| 114 | list_del(entry: &fd->list); |
| 115 | mutex_unlock(lock: &func_lock); |
| 116 | } |
| 117 | EXPORT_SYMBOL_GPL(usb_function_unregister); |
| 118 |