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https://github.com/edk2-porting/linux-next.git
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0062f6e56f
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: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Felipe Balbi <balbi@ti.com>
117 lines
2.2 KiB
C
117 lines
2.2 KiB
C
#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/err.h>
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#include <linux/usb/composite.h>
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static LIST_HEAD(func_list);
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static DEFINE_MUTEX(func_lock);
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static struct usb_function_instance *try_get_usb_function_instance(const char *name)
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{
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struct usb_function_driver *fd;
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struct usb_function_instance *fi;
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fi = ERR_PTR(-ENOENT);
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mutex_lock(&func_lock);
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list_for_each_entry(fd, &func_list, list) {
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if (strcmp(name, fd->name))
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continue;
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if (!try_module_get(fd->mod)) {
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fi = ERR_PTR(-EBUSY);
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break;
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}
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fi = fd->alloc_inst();
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if (IS_ERR(fi))
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module_put(fd->mod);
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else
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fi->fd = fd;
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break;
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}
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mutex_unlock(&func_lock);
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return fi;
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}
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struct usb_function_instance *usb_get_function_instance(const char *name)
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{
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struct usb_function_instance *fi;
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int ret;
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fi = try_get_usb_function_instance(name);
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if (!IS_ERR(fi))
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return fi;
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ret = PTR_ERR(fi);
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if (ret != -ENOENT)
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return fi;
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ret = request_module("usbfunc:%s", name);
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if (ret < 0)
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return ERR_PTR(ret);
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return try_get_usb_function_instance(name);
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}
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EXPORT_SYMBOL_GPL(usb_get_function_instance);
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struct usb_function *usb_get_function(struct usb_function_instance *fi)
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{
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struct usb_function *f;
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f = fi->fd->alloc_func(fi);
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if (IS_ERR(f))
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return f;
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f->fi = fi;
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return f;
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}
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EXPORT_SYMBOL_GPL(usb_get_function);
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void usb_put_function_instance(struct usb_function_instance *fi)
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{
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struct module *mod;
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if (!fi)
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return;
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mod = fi->fd->mod;
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fi->free_func_inst(fi);
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module_put(mod);
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}
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EXPORT_SYMBOL_GPL(usb_put_function_instance);
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void usb_put_function(struct usb_function *f)
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{
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if (!f)
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return;
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f->free_func(f);
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}
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EXPORT_SYMBOL_GPL(usb_put_function);
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int usb_function_register(struct usb_function_driver *newf)
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{
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struct usb_function_driver *fd;
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int ret;
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ret = -EEXIST;
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mutex_lock(&func_lock);
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list_for_each_entry(fd, &func_list, list) {
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if (!strcmp(fd->name, newf->name))
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goto out;
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}
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ret = 0;
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list_add_tail(&newf->list, &func_list);
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out:
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mutex_unlock(&func_lock);
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return ret;
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}
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EXPORT_SYMBOL_GPL(usb_function_register);
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void usb_function_unregister(struct usb_function_driver *fd)
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{
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mutex_lock(&func_lock);
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list_del(&fd->list);
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mutex_unlock(&func_lock);
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}
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EXPORT_SYMBOL_GPL(usb_function_unregister);
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