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