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path: root/drivers/usb/gadget/functions.c
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Diffstat (limited to 'drivers/usb/gadget/functions.c')
-rw-r--r--drivers/usb/gadget/functions.c117
1 files changed, 117 insertions, 0 deletions
diff --git a/drivers/usb/gadget/functions.c b/drivers/usb/gadget/functions.c
new file mode 100644
index 000000000..203361a64
--- /dev/null
+++ b/drivers/usb/gadget/functions.c
@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/err.h>
+
+#include <linux/usb/composite.h>
+
+static LIST_HEAD(func_list);
+static DEFINE_MUTEX(func_lock);
+
+static struct usb_function_instance *try_get_usb_function_instance(const char *name)
+{
+ struct usb_function_driver *fd;
+ struct usb_function_instance *fi;
+
+ fi = ERR_PTR(-ENOENT);
+ mutex_lock(&func_lock);
+ list_for_each_entry(fd, &func_list, list) {
+
+ if (strcmp(name, fd->name))
+ continue;
+
+ if (!try_module_get(fd->mod)) {
+ fi = ERR_PTR(-EBUSY);
+ break;
+ }
+ fi = fd->alloc_inst();
+ if (IS_ERR(fi))
+ module_put(fd->mod);
+ else
+ fi->fd = fd;
+ break;
+ }
+ mutex_unlock(&func_lock);
+ return fi;
+}
+
+struct usb_function_instance *usb_get_function_instance(const char *name)
+{
+ struct usb_function_instance *fi;
+ int ret;
+
+ fi = try_get_usb_function_instance(name);
+ if (!IS_ERR(fi))
+ return fi;
+ ret = PTR_ERR(fi);
+ if (ret != -ENOENT)
+ return fi;
+ ret = request_module("usbfunc:%s", name);
+ if (ret < 0)
+ return ERR_PTR(ret);
+ return try_get_usb_function_instance(name);
+}
+EXPORT_SYMBOL_GPL(usb_get_function_instance);
+
+struct usb_function *usb_get_function(struct usb_function_instance *fi)
+{
+ struct usb_function *f;
+
+ f = fi->fd->alloc_func(fi);
+ if (IS_ERR(f))
+ return f;
+ f->fi = fi;
+ return f;
+}
+EXPORT_SYMBOL_GPL(usb_get_function);
+
+void usb_put_function_instance(struct usb_function_instance *fi)
+{
+ struct module *mod;
+
+ if (!fi)
+ return;
+
+ mod = fi->fd->mod;
+ fi->free_func_inst(fi);
+ module_put(mod);
+}
+EXPORT_SYMBOL_GPL(usb_put_function_instance);
+
+void usb_put_function(struct usb_function *f)
+{
+ if (!f)
+ return;
+
+ f->free_func(f);
+}
+EXPORT_SYMBOL_GPL(usb_put_function);
+
+int usb_function_register(struct usb_function_driver *newf)
+{
+ struct usb_function_driver *fd;
+ int ret;
+
+ ret = -EEXIST;
+
+ mutex_lock(&func_lock);
+ list_for_each_entry(fd, &func_list, list) {
+ if (!strcmp(fd->name, newf->name))
+ goto out;
+ }
+ ret = 0;
+ list_add_tail(&newf->list, &func_list);
+out:
+ mutex_unlock(&func_lock);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(usb_function_register);
+
+void usb_function_unregister(struct usb_function_driver *fd)
+{
+ mutex_lock(&func_lock);
+ list_del(&fd->list);
+ mutex_unlock(&func_lock);
+}
+EXPORT_SYMBOL_GPL(usb_function_unregister);