Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1701 insertions, 0 deletions

diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
new file mode 100644
index 000000000..4dcf29577
--- /dev/null
+++ b/drivers/usb/gadget/configfs.c
@@ -0,0 +1,1701 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/configfs.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/nls.h>
+#include <linux/usb/composite.h>
+#include <linux/usb/gadget_configfs.h>
+#include "configfs.h"
+#include "u_f.h"
+#include "u_os_desc.h"
+
+int check_user_usb_string(const char *name,
+		struct usb_gadget_strings *stringtab_dev)
+{
+	u16 num;
+	int ret;
+
+	ret = kstrtou16(name, 0, &num);
+	if (ret)
+		return ret;
+
+	if (!usb_validate_langid(num))
+		return -EINVAL;
+
+	stringtab_dev->language = num;
+	return 0;
+}
+
+#define MAX_NAME_LEN	40
+#define MAX_USB_STRING_LANGS 2
+
+static const struct usb_descriptor_header *otg_desc[2];
+
+struct gadget_info {
+	struct config_group group;
+	struct config_group functions_group;
+	struct config_group configs_group;
+	struct config_group strings_group;
+	struct config_group os_desc_group;
+
+	struct mutex lock;
+	struct usb_gadget_strings *gstrings[MAX_USB_STRING_LANGS + 1];
+	struct list_head string_list;
+	struct list_head available_func;
+
+	struct usb_composite_driver composite;
+	struct usb_composite_dev cdev;
+	bool use_os_desc;
+	char b_vendor_code;
+	char qw_sign[OS_STRING_QW_SIGN_LEN];
+	spinlock_t spinlock;
+	bool unbind;
+};
+
+static inline struct gadget_info *to_gadget_info(struct config_item *item)
+{
+	return container_of(to_config_group(item), struct gadget_info, group);
+}
+
+struct config_usb_cfg {
+	struct config_group group;
+	struct config_group strings_group;
+	struct list_head string_list;
+	struct usb_configuration c;
+	struct list_head func_list;
+	struct usb_gadget_strings *gstrings[MAX_USB_STRING_LANGS + 1];
+};
+
+static inline struct config_usb_cfg *to_config_usb_cfg(struct config_item *item)
+{
+	return container_of(to_config_group(item), struct config_usb_cfg,
+			group);
+}
+
+static inline struct gadget_info *cfg_to_gadget_info(struct config_usb_cfg *cfg)
+{
+	return container_of(cfg->c.cdev, struct gadget_info, cdev);
+}
+
+struct gadget_strings {
+	struct usb_gadget_strings stringtab_dev;
+	struct usb_string strings[USB_GADGET_FIRST_AVAIL_IDX];
+	char *manufacturer;
+	char *product;
+	char *serialnumber;
+
+	struct config_group group;
+	struct list_head list;
+};
+
+struct gadget_config_name {
+	struct usb_gadget_strings stringtab_dev;
+	struct usb_string strings;
+	char *configuration;
+
+	struct config_group group;
+	struct list_head list;
+};
+
+#define USB_MAX_STRING_WITH_NULL_LEN	(USB_MAX_STRING_LEN+1)
+
+static int usb_string_copy(const char *s, char **s_copy)
+{
+	int ret;
+	char *str;
+	char *copy = *s_copy;
+	ret = strlen(s);
+	if (ret > USB_MAX_STRING_LEN)
+		return -EOVERFLOW;
+
+	if (copy) {
+		str = copy;
+	} else {
+		str = kmalloc(USB_MAX_STRING_WITH_NULL_LEN, GFP_KERNEL);
+		if (!str)
+			return -ENOMEM;
+	}
+	strcpy(str, s);
+	if (str[ret - 1] == '\n')
+		str[ret - 1] = '\0';
+	*s_copy = str;
+	return 0;
+}
+
+#define GI_DEVICE_DESC_SIMPLE_R_u8(__name)	\
+static ssize_t gadget_dev_desc_##__name##_show(struct config_item *item, \
+			char *page)	\
+{	\
+	return sprintf(page, "0x%02x\n", \
+		to_gadget_info(item)->cdev.desc.__name); \
+}
+
+#define GI_DEVICE_DESC_SIMPLE_R_u16(__name)	\
+static ssize_t gadget_dev_desc_##__name##_show(struct config_item *item, \
+			char *page)	\
+{	\
+	return sprintf(page, "0x%04x\n", \
+		le16_to_cpup(&to_gadget_info(item)->cdev.desc.__name)); \
+}
+
+
+#define GI_DEVICE_DESC_SIMPLE_W_u8(_name)		\
+static ssize_t gadget_dev_desc_##_name##_store(struct config_item *item, \
+		const char *page, size_t len)		\
+{							\
+	u8 val;						\
+	int ret;					\
+	ret = kstrtou8(page, 0, &val);			\
+	if (ret)					\
+		return ret;				\
+	to_gadget_info(item)->cdev.desc._name = val;	\
+	return len;					\
+}
+
+#define GI_DEVICE_DESC_SIMPLE_W_u16(_name)	\
+static ssize_t gadget_dev_desc_##_name##_store(struct config_item *item, \
+		const char *page, size_t len)		\
+{							\
+	u16 val;					\
+	int ret;					\
+	ret = kstrtou16(page, 0, &val);			\
+	if (ret)					\
+		return ret;				\
+	to_gadget_info(item)->cdev.desc._name = cpu_to_le16p(&val);	\
+	return len;					\
+}
+
+#define GI_DEVICE_DESC_SIMPLE_RW(_name, _type)	\
+	GI_DEVICE_DESC_SIMPLE_R_##_type(_name)	\
+	GI_DEVICE_DESC_SIMPLE_W_##_type(_name)
+
+GI_DEVICE_DESC_SIMPLE_R_u16(bcdUSB);
+GI_DEVICE_DESC_SIMPLE_RW(bDeviceClass, u8);
+GI_DEVICE_DESC_SIMPLE_RW(bDeviceSubClass, u8);
+GI_DEVICE_DESC_SIMPLE_RW(bDeviceProtocol, u8);
+GI_DEVICE_DESC_SIMPLE_RW(bMaxPacketSize0, u8);
+GI_DEVICE_DESC_SIMPLE_RW(idVendor, u16);
+GI_DEVICE_DESC_SIMPLE_RW(idProduct, u16);
+GI_DEVICE_DESC_SIMPLE_R_u16(bcdDevice);
+
+static ssize_t is_valid_bcd(u16 bcd_val)
+{
+	if ((bcd_val & 0xf) > 9)
+		return -EINVAL;
+	if (((bcd_val >> 4) & 0xf) > 9)
+		return -EINVAL;
+	if (((bcd_val >> 8) & 0xf) > 9)
+		return -EINVAL;
+	if (((bcd_val >> 12) & 0xf) > 9)
+		return -EINVAL;
+	return 0;
+}
+
+static ssize_t gadget_dev_desc_bcdDevice_store(struct config_item *item,
+		const char *page, size_t len)
+{
+	u16 bcdDevice;
+	int ret;
+
+	ret = kstrtou16(page, 0, &bcdDevice);
+	if (ret)
+		return ret;
+	ret = is_valid_bcd(bcdDevice);
+	if (ret)
+		return ret;
+
+	to_gadget_info(item)->cdev.desc.bcdDevice = cpu_to_le16(bcdDevice);
+	return len;
+}
+
+static ssize_t gadget_dev_desc_bcdUSB_store(struct config_item *item,
+		const char *page, size_t len)
+{
+	u16 bcdUSB;
+	int ret;
+
+	ret = kstrtou16(page, 0, &bcdUSB);
+	if (ret)
+		return ret;
+	ret = is_valid_bcd(bcdUSB);
+	if (ret)
+		return ret;
+
+	to_gadget_info(item)->cdev.desc.bcdUSB = cpu_to_le16(bcdUSB);
+	return len;
+}
+
+static ssize_t gadget_dev_desc_UDC_show(struct config_item *item, char *page)
+{
+	struct gadget_info *gi = to_gadget_info(item);
+	char *udc_name;
+	int ret;
+
+	mutex_lock(&gi->lock);
+	udc_name = gi->composite.gadget_driver.udc_name;
+	ret = sprintf(page, "%s\n", udc_name ?: "");
+	mutex_unlock(&gi->lock);
+
+	return ret;
+}
+
+static int unregister_gadget(struct gadget_info *gi)
+{
+	int ret;
+
+	if (!gi->composite.gadget_driver.udc_name)
+		return -ENODEV;
+
+	ret = usb_gadget_unregister_driver(&gi->composite.gadget_driver);
+	if (ret)
+		return ret;
+	kfree(gi->composite.gadget_driver.udc_name);
+	gi->composite.gadget_driver.udc_name = NULL;
+	return 0;
+}
+
+static ssize_t gadget_dev_desc_UDC_store(struct config_item *item,
+		const char *page, size_t len)
+{
+	struct gadget_info *gi = to_gadget_info(item);
+	char *name;
+	int ret;
+
+	if (strlen(page) < len)
+		return -EOVERFLOW;
+
+	name = kstrdup(page, GFP_KERNEL);
+	if (!name)
+		return -ENOMEM;
+	if (name[len - 1] == '\n')
+		name[len - 1] = '\0';
+
+	mutex_lock(&gi->lock);
+
+	if (!strlen(name)) {
+		ret = unregister_gadget(gi);
+		if (ret)
+			goto err;
+		kfree(name);
+	} else {
+		if (gi->composite.gadget_driver.udc_name) {
+			ret = -EBUSY;
+			goto err;
+		}
+		gi->composite.gadget_driver.udc_name = name;
+		ret = usb_gadget_register_driver(&gi->composite.gadget_driver);
+		if (ret) {
+			gi->composite.gadget_driver.udc_name = NULL;
+			goto err;
+		}
+	}
+	mutex_unlock(&gi->lock);
+	return len;
+err:
+	kfree(name);
+	mutex_unlock(&gi->lock);
+	return ret;
+}
+
+static ssize_t gadget_dev_desc_max_speed_show(struct config_item *item,
+					      char *page)
+{
+	enum usb_device_speed speed = to_gadget_info(item)->composite.max_speed;
+
+	return sprintf(page, "%s\n", usb_speed_string(speed));
+}
+
+static ssize_t gadget_dev_desc_max_speed_store(struct config_item *item,
+					       const char *page, size_t len)
+{
+	struct gadget_info *gi = to_gadget_info(item);
+
+	mutex_lock(&gi->lock);
+
+	/* Prevent changing of max_speed after the driver is binded */
+	if (gi->composite.gadget_driver.udc_name)
+		goto err;
+
+	if (strncmp(page, "super-speed-plus", 16) == 0)
+		gi->composite.max_speed = USB_SPEED_SUPER_PLUS;
+	else if (strncmp(page, "super-speed", 11) == 0)
+		gi->composite.max_speed = USB_SPEED_SUPER;
+	else if (strncmp(page, "high-speed", 10) == 0)
+		gi->composite.max_speed = USB_SPEED_HIGH;
+	else if (strncmp(page, "full-speed", 10) == 0)
+		gi->composite.max_speed = USB_SPEED_FULL;
+	else if (strncmp(page, "low-speed", 9) == 0)
+		gi->composite.max_speed = USB_SPEED_LOW;
+	else
+		goto err;
+
+	gi->composite.gadget_driver.max_speed = gi->composite.max_speed;
+
+	mutex_unlock(&gi->lock);
+	return len;
+err:
+	mutex_unlock(&gi->lock);
+	return -EINVAL;
+}
+
+CONFIGFS_ATTR(gadget_dev_desc_, bDeviceClass);
+CONFIGFS_ATTR(gadget_dev_desc_, bDeviceSubClass);
+CONFIGFS_ATTR(gadget_dev_desc_, bDeviceProtocol);
+CONFIGFS_ATTR(gadget_dev_desc_, bMaxPacketSize0);
+CONFIGFS_ATTR(gadget_dev_desc_, idVendor);
+CONFIGFS_ATTR(gadget_dev_desc_, idProduct);
+CONFIGFS_ATTR(gadget_dev_desc_, bcdDevice);
+CONFIGFS_ATTR(gadget_dev_desc_, bcdUSB);
+CONFIGFS_ATTR(gadget_dev_desc_, UDC);
+CONFIGFS_ATTR(gadget_dev_desc_, max_speed);
+
+static struct configfs_attribute *gadget_root_attrs[] = {
+	&gadget_dev_desc_attr_bDeviceClass,
+	&gadget_dev_desc_attr_bDeviceSubClass,
+	&gadget_dev_desc_attr_bDeviceProtocol,
+	&gadget_dev_desc_attr_bMaxPacketSize0,
+	&gadget_dev_desc_attr_idVendor,
+	&gadget_dev_desc_attr_idProduct,
+	&gadget_dev_desc_attr_bcdDevice,
+	&gadget_dev_desc_attr_bcdUSB,
+	&gadget_dev_desc_attr_UDC,
+	&gadget_dev_desc_attr_max_speed,
+	NULL,
+};
+
+static inline struct gadget_strings *to_gadget_strings(struct config_item *item)
+{
+	return container_of(to_config_group(item), struct gadget_strings,
+			 group);
+}
+
+static inline struct gadget_config_name *to_gadget_config_name(
+		struct config_item *item)
+{
+	return container_of(to_config_group(item), struct gadget_config_name,
+			 group);
+}
+
+static inline struct usb_function_instance *to_usb_function_instance(
+		struct config_item *item)
+{
+	return container_of(to_config_group(item),
+			 struct usb_function_instance, group);
+}
+
+static void gadget_info_attr_release(struct config_item *item)
+{
+	struct gadget_info *gi = to_gadget_info(item);
+
+	WARN_ON(!list_empty(&gi->cdev.configs));
+	WARN_ON(!list_empty(&gi->string_list));
+	WARN_ON(!list_empty(&gi->available_func));
+	kfree(gi->composite.gadget_driver.function);
+	kfree(gi->composite.gadget_driver.driver.name);
+	kfree(gi);
+}
+
+static struct configfs_item_operations gadget_root_item_ops = {
+	.release                = gadget_info_attr_release,
+};
+
+static void gadget_config_attr_release(struct config_item *item)
+{
+	struct config_usb_cfg *cfg = to_config_usb_cfg(item);
+
+	WARN_ON(!list_empty(&cfg->c.functions));
+	list_del(&cfg->c.list);
+	kfree(cfg->c.label);
+	kfree(cfg);
+}
+
+static int config_usb_cfg_link(
+	struct config_item *usb_cfg_ci,
+	struct config_item *usb_func_ci)
+{
+	struct config_usb_cfg *cfg = to_config_usb_cfg(usb_cfg_ci);
+	struct gadget_info *gi = cfg_to_gadget_info(cfg);
+
+	struct usb_function_instance *fi =
+			to_usb_function_instance(usb_func_ci);
+	struct usb_function_instance *a_fi = NULL, *iter;
+	struct usb_function *f;
+	int ret;
+
+	mutex_lock(&gi->lock);
+	/*
+	 * Make sure this function is from within our _this_ gadget and not
+	 * from another gadget or a random directory.
+	 * Also a function instance can only be linked once.
+	 */
+
+	if (gi->composite.gadget_driver.udc_name) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	list_for_each_entry(iter, &gi->available_func, cfs_list) {
+		if (iter != fi)
+			continue;
+		a_fi = iter;
+		break;
+	}
+	if (!a_fi) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	list_for_each_entry(f, &cfg->func_list, list) {
+		if (f->fi == fi) {
+			ret = -EEXIST;
+			goto out;
+		}
+	}
+
+	f = usb_get_function(fi);
+	if (IS_ERR(f)) {
+		ret = PTR_ERR(f);
+		goto out;
+	}
+
+	/* stash the function until we bind it to the gadget */
+	list_add_tail(&f->list, &cfg->func_list);
+	ret = 0;
+out:
+	mutex_unlock(&gi->lock);
+	return ret;
+}
+
+static void config_usb_cfg_unlink(
+	struct config_item *usb_cfg_ci,
+	struct config_item *usb_func_ci)
+{
+	struct config_usb_cfg *cfg = to_config_usb_cfg(usb_cfg_ci);
+	struct gadget_info *gi = cfg_to_gadget_info(cfg);
+
+	struct usb_function_instance *fi =
+			to_usb_function_instance(usb_func_ci);
+	struct usb_function *f;
+
+	/*
+	 * ideally I would like to forbid to unlink functions while a gadget is
+	 * bound to an UDC. Since this isn't possible at the moment, we simply
+	 * force an unbind, the function is available here and then we can
+	 * remove the function.
+	 */
+	mutex_lock(&gi->lock);
+	if (gi->composite.gadget_driver.udc_name)
+		unregister_gadget(gi);
+	WARN_ON(gi->composite.gadget_driver.udc_name);
+
+	list_for_each_entry(f, &cfg->func_list, list) {
+		if (f->fi == fi) {
+			list_del(&f->list);
+			usb_put_function(f);
+			mutex_unlock(&gi->lock);
+			return;
+		}
+	}
+	mutex_unlock(&gi->lock);
+	WARN(1, "Unable to locate function to unbind\n");
+}
+
+static struct configfs_item_operations gadget_config_item_ops = {
+	.release                = gadget_config_attr_release,
+	.allow_link             = config_usb_cfg_link,
+	.drop_link              = config_usb_cfg_unlink,
+};
+
+
+static ssize_t gadget_config_desc_MaxPower_show(struct config_item *item,
+		char *page)
+{
+	struct config_usb_cfg *cfg = to_config_usb_cfg(item);
+
+	return sprintf(page, "%u\n", cfg->c.MaxPower);
+}
+
+static ssize_t gadget_config_desc_MaxPower_store(struct config_item *item,
+		const char *page, size_t len)
+{
+	struct config_usb_cfg *cfg = to_config_usb_cfg(item);
+	u16 val;
+	int ret;
+	ret = kstrtou16(page, 0, &val);
+	if (ret)
+		return ret;
+	if (DIV_ROUND_UP(val, 8) > 0xff)
+		return -ERANGE;
+	cfg->c.MaxPower = val;
+	return len;
+}
+
+static ssize_t gadget_config_desc_bmAttributes_show(struct config_item *item,
+		char *page)
+{
+	struct config_usb_cfg *cfg = to_config_usb_cfg(item);
+
+	return sprintf(page, "0x%02x\n", cfg->c.bmAttributes);
+}
+
+static ssize_t gadget_config_desc_bmAttributes_store(struct config_item *item,
+		const char *page, size_t len)
+{
+	struct config_usb_cfg *cfg = to_config_usb_cfg(item);
+	u8 val;
+	int ret;
+	ret = kstrtou8(page, 0, &val);
+	if (ret)
+		return ret;
+	if (!(val & USB_CONFIG_ATT_ONE))
+		return -EINVAL;
+	if (val & ~(USB_CONFIG_ATT_ONE | USB_CONFIG_ATT_SELFPOWER |
+				USB_CONFIG_ATT_WAKEUP))
+		return -EINVAL;
+	cfg->c.bmAttributes = val;
+	return len;
+}
+
+CONFIGFS_ATTR(gadget_config_desc_, MaxPower);
+CONFIGFS_ATTR(gadget_config_desc_, bmAttributes);
+
+static struct configfs_attribute *gadget_config_attrs[] = {
+	&gadget_config_desc_attr_MaxPower,
+	&gadget_config_desc_attr_bmAttributes,
+	NULL,
+};
+
+static const struct config_item_type gadget_config_type = {
+	.ct_item_ops	= &gadget_config_item_ops,
+	.ct_attrs	= gadget_config_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static const struct config_item_type gadget_root_type = {
+	.ct_item_ops	= &gadget_root_item_ops,
+	.ct_attrs	= gadget_root_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static void composite_init_dev(struct usb_composite_dev *cdev)
+{
+	spin_lock_init(&cdev->lock);
+	INIT_LIST_HEAD(&cdev->configs);
+	INIT_LIST_HEAD(&cdev->gstrings);
+}
+
+static struct config_group *function_make(
+		struct config_group *group,
+		const char *name)
+{
+	struct gadget_info *gi;
+	struct usb_function_instance *fi;
+	char buf[MAX_NAME_LEN];
+	char *func_name;
+	char *instance_name;
+	int ret;
+
+	ret = snprintf(buf, MAX_NAME_LEN, "%s", name);
+	if (ret >= MAX_NAME_LEN)
+		return ERR_PTR(-ENAMETOOLONG);
+
+	func_name = buf;
+	instance_name = strchr(func_name, '.');
+	if (!instance_name) {
+		pr_err("Unable to locate . in FUNC.INSTANCE\n");
+		return ERR_PTR(-EINVAL);
+	}
+	*instance_name = '\0';
+	instance_name++;
+
+	fi = usb_get_function_instance(func_name);
+	if (IS_ERR(fi))
+		return ERR_CAST(fi);
+
+	ret = config_item_set_name(&fi->group.cg_item, "%s", name);
+	if (ret) {
+		usb_put_function_instance(fi);
+		return ERR_PTR(ret);
+	}
+	if (fi->set_inst_name) {
+		ret = fi->set_inst_name(fi, instance_name);
+		if (ret) {
+			usb_put_function_instance(fi);
+			return ERR_PTR(ret);
+		}
+	}
+
+	gi = container_of(group, struct gadget_info, functions_group);
+
+	mutex_lock(&gi->lock);
+	list_add_tail(&fi->cfs_list, &gi->available_func);
+	mutex_unlock(&gi->lock);
+	return &fi->group;
+}
+
+static void function_drop(
+		struct config_group *group,
+		struct config_item *item)
+{
+	struct usb_function_instance *fi = to_usb_function_instance(item);
+	struct gadget_info *gi;
+
+	gi = container_of(group, struct gadget_info, functions_group);
+
+	mutex_lock(&gi->lock);
+	list_del(&fi->cfs_list);
+	mutex_unlock(&gi->lock);
+	config_item_put(item);
+}
+
+static struct configfs_group_operations functions_ops = {
+	.make_group     = &function_make,
+	.drop_item      = &function_drop,
+};
+
+static const struct config_item_type functions_type = {
+	.ct_group_ops   = &functions_ops,
+	.ct_owner       = THIS_MODULE,
+};
+
+GS_STRINGS_RW(gadget_config_name, configuration);
+
+static struct configfs_attribute *gadget_config_name_langid_attrs[] = {
+	&gadget_config_name_attr_configuration,
+	NULL,
+};
+
+static void gadget_config_name_attr_release(struct config_item *item)
+{
+	struct gadget_config_name *cn = to_gadget_config_name(item);
+
+	kfree(cn->configuration);
+
+	list_del(&cn->list);
+	kfree(cn);
+}
+
+USB_CONFIG_STRING_RW_OPS(gadget_config_name);
+USB_CONFIG_STRINGS_LANG(gadget_config_name, config_usb_cfg);
+
+static struct config_group *config_desc_make(
+		struct config_group *group,
+		const char *name)
+{
+	struct gadget_info *gi;
+	struct config_usb_cfg *cfg;
+	char buf[MAX_NAME_LEN];
+	char *num_str;
+	u8 num;
+	int ret;
+
+	gi = container_of(group, struct gadget_info, configs_group);
+	ret = snprintf(buf, MAX_NAME_LEN, "%s", name);
+	if (ret >= MAX_NAME_LEN)
+		return ERR_PTR(-ENAMETOOLONG);
+
+	num_str = strchr(buf, '.');
+	if (!num_str) {
+		pr_err("Unable to locate . in name.bConfigurationValue\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	*num_str = '\0';
+	num_str++;
+
+	if (!strlen(buf))
+		return ERR_PTR(-EINVAL);
+
+	ret = kstrtou8(num_str, 0, &num);
+	if (ret)
+		return ERR_PTR(ret);
+
+	cfg = kzalloc(sizeof(*cfg), GFP_KERNEL);
+	if (!cfg)
+		return ERR_PTR(-ENOMEM);
+	cfg->c.label = kstrdup(buf, GFP_KERNEL);
+	if (!cfg->c.label) {
+		ret = -ENOMEM;
+		goto err;
+	}
+	cfg->c.bConfigurationValue = num;
+	cfg->c.MaxPower = CONFIG_USB_GADGET_VBUS_DRAW;
+	cfg->c.bmAttributes = USB_CONFIG_ATT_ONE;
+	INIT_LIST_HEAD(&cfg->string_list);
+	INIT_LIST_HEAD(&cfg->func_list);
+
+	config_group_init_type_name(&cfg->group, name,
+				&gadget_config_type);
+
+	config_group_init_type_name(&cfg->strings_group, "strings",
+			&gadget_config_name_strings_type);
+	configfs_add_default_group(&cfg->strings_group, &cfg->group);
+
+	ret = usb_add_config_only(&gi->cdev, &cfg->c);
+	if (ret)
+		goto err;
+
+	return &cfg->group;
+err:
+	kfree(cfg->c.label);
+	kfree(cfg);
+	return ERR_PTR(ret);
+}
+
+static void config_desc_drop(
+		struct config_group *group,
+		struct config_item *item)
+{
+	config_item_put(item);
+}
+
+static struct configfs_group_operations config_desc_ops = {
+	.make_group     = &config_desc_make,
+	.drop_item      = &config_desc_drop,
+};
+
+static const struct config_item_type config_desc_type = {
+	.ct_group_ops   = &config_desc_ops,
+	.ct_owner       = THIS_MODULE,
+};
+
+GS_STRINGS_RW(gadget_strings, manufacturer);
+GS_STRINGS_RW(gadget_strings, product);
+GS_STRINGS_RW(gadget_strings, serialnumber);
+
+static struct configfs_attribute *gadget_strings_langid_attrs[] = {
+	&gadget_strings_attr_manufacturer,
+	&gadget_strings_attr_product,
+	&gadget_strings_attr_serialnumber,
+	NULL,
+};
+
+static void gadget_strings_attr_release(struct config_item *item)
+{
+	struct gadget_strings *gs = to_gadget_strings(item);
+
+	kfree(gs->manufacturer);
+	kfree(gs->product);
+	kfree(gs->serialnumber);
+
+	list_del(&gs->list);
+	kfree(gs);
+}
+
+USB_CONFIG_STRING_RW_OPS(gadget_strings);
+USB_CONFIG_STRINGS_LANG(gadget_strings, gadget_info);
+
+static inline struct gadget_info *os_desc_item_to_gadget_info(
+		struct config_item *item)
+{
+	return container_of(to_config_group(item),
+			struct gadget_info, os_desc_group);
+}
+
+static ssize_t os_desc_use_show(struct config_item *item, char *page)
+{
+	return sprintf(page, "%d\n",
+			os_desc_item_to_gadget_info(item)->use_os_desc);
+}
+
+static ssize_t os_desc_use_store(struct config_item *item, const char *page,
+				 size_t len)
+{
+	struct gadget_info *gi = os_desc_item_to_gadget_info(item);
+	int ret;
+	bool use;
+
+	mutex_lock(&gi->lock);
+	ret = strtobool(page, &use);
+	if (!ret) {
+		gi->use_os_desc = use;
+		ret = len;
+	}
+	mutex_unlock(&gi->lock);
+
+	return ret;
+}
+
+static ssize_t os_desc_b_vendor_code_show(struct config_item *item, char *page)
+{
+	return sprintf(page, "0x%02x\n",
+			os_desc_item_to_gadget_info(item)->b_vendor_code);
+}
+
+static ssize_t os_desc_b_vendor_code_store(struct config_item *item,
+					   const char *page, size_t len)
+{
+	struct gadget_info *gi = os_desc_item_to_gadget_info(item);
+	int ret;
+	u8 b_vendor_code;
+
+	mutex_lock(&gi->lock);
+	ret = kstrtou8(page, 0, &b_vendor_code);
+	if (!ret) {
+		gi->b_vendor_code = b_vendor_code;
+		ret = len;
+	}
+	mutex_unlock(&gi->lock);
+
+	return ret;
+}
+
+static ssize_t os_desc_qw_sign_show(struct config_item *item, char *page)
+{
+	struct gadget_info *gi = os_desc_item_to_gadget_info(item);
+	int res;
+
+	res = utf16s_to_utf8s((wchar_t *) gi->qw_sign, OS_STRING_QW_SIGN_LEN,
+			      UTF16_LITTLE_ENDIAN, page, PAGE_SIZE - 1);
+	page[res++] = '\n';
+
+	return res;
+}
+
+static ssize_t os_desc_qw_sign_store(struct config_item *item, const char *page,
+				     size_t len)
+{
+	struct gadget_info *gi = os_desc_item_to_gadget_info(item);
+	int res, l;
+
+	l = min((int)len, OS_STRING_QW_SIGN_LEN >> 1);
+	if (page[l - 1] == '\n')
+		--l;
+
+	mutex_lock(&gi->lock);
+	res = utf8s_to_utf16s(page, l,
+			      UTF16_LITTLE_ENDIAN, (wchar_t *) gi->qw_sign,
+			      OS_STRING_QW_SIGN_LEN);
+	if (res > 0)
+		res = len;
+	mutex_unlock(&gi->lock);
+
+	return res;
+}
+
+CONFIGFS_ATTR(os_desc_, use);
+CONFIGFS_ATTR(os_desc_, b_vendor_code);
+CONFIGFS_ATTR(os_desc_, qw_sign);
+
+static struct configfs_attribute *os_desc_attrs[] = {
+	&os_desc_attr_use,
+	&os_desc_attr_b_vendor_code,
+	&os_desc_attr_qw_sign,
+	NULL,
+};
+
+static int os_desc_link(struct config_item *os_desc_ci,
+			struct config_item *usb_cfg_ci)
+{
+	struct gadget_info *gi = os_desc_item_to_gadget_info(os_desc_ci);
+	struct usb_composite_dev *cdev = &gi->cdev;
+	struct config_usb_cfg *c_target = to_config_usb_cfg(usb_cfg_ci);
+	struct usb_configuration *c = NULL, *iter;
+	int ret;
+
+	mutex_lock(&gi->lock);
+	list_for_each_entry(iter, &cdev->configs, list) {
+		if (iter != &c_target->c)
+			continue;
+		c = iter;
+		break;
+	}
+	if (!c) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (cdev->os_desc_config) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	cdev->os_desc_config = &c_target->c;
+	ret = 0;
+
+out:
+	mutex_unlock(&gi->lock);
+	return ret;
+}
+
+static void os_desc_unlink(struct config_item *os_desc_ci,
+			  struct config_item *usb_cfg_ci)
+{
+	struct gadget_info *gi = os_desc_item_to_gadget_info(os_desc_ci);
+	struct usb_composite_dev *cdev = &gi->cdev;
+
+	mutex_lock(&gi->lock);
+	if (gi->composite.gadget_driver.udc_name)
+		unregister_gadget(gi);
+	cdev->os_desc_config = NULL;
+	WARN_ON(gi->composite.gadget_driver.udc_name);
+	mutex_unlock(&gi->lock);
+}
+
+static struct configfs_item_operations os_desc_ops = {
+	.allow_link		= os_desc_link,
+	.drop_link		= os_desc_unlink,
+};
+
+static struct config_item_type os_desc_type = {
+	.ct_item_ops	= &os_desc_ops,
+	.ct_attrs	= os_desc_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static inline struct usb_os_desc_ext_prop
+*to_usb_os_desc_ext_prop(struct config_item *item)
+{
+	return container_of(item, struct usb_os_desc_ext_prop, item);
+}
+
+static ssize_t ext_prop_type_show(struct config_item *item, char *page)
+{
+	return sprintf(page, "%d\n", to_usb_os_desc_ext_prop(item)->type);
+}
+
+static ssize_t ext_prop_type_store(struct config_item *item,
+				   const char *page, size_t len)
+{
+	struct usb_os_desc_ext_prop *ext_prop = to_usb_os_desc_ext_prop(item);
+	struct usb_os_desc *desc = to_usb_os_desc(ext_prop->item.ci_parent);
+	u8 type;
+	int ret;
+
+	if (desc->opts_mutex)
+		mutex_lock(desc->opts_mutex);
+	ret = kstrtou8(page, 0, &type);
+	if (ret)
+		goto end;
+	if (type < USB_EXT_PROP_UNICODE || type > USB_EXT_PROP_UNICODE_MULTI) {
+		ret = -EINVAL;
+		goto end;
+	}
+
+	if ((ext_prop->type == USB_EXT_PROP_BINARY ||
+	    ext_prop->type == USB_EXT_PROP_LE32 ||
+	    ext_prop->type == USB_EXT_PROP_BE32) &&
+	    (type == USB_EXT_PROP_UNICODE ||
+	    type == USB_EXT_PROP_UNICODE_ENV ||
+	    type == USB_EXT_PROP_UNICODE_LINK))
+		ext_prop->data_len <<= 1;
+	else if ((ext_prop->type == USB_EXT_PROP_UNICODE ||
+		   ext_prop->type == USB_EXT_PROP_UNICODE_ENV ||
+		   ext_prop->type == USB_EXT_PROP_UNICODE_LINK) &&
+		   (type == USB_EXT_PROP_BINARY ||
+		   type == USB_EXT_PROP_LE32 ||
+		   type == USB_EXT_PROP_BE32))
+		ext_prop->data_len >>= 1;
+	ext_prop->type = type;
+	ret = len;
+
+end:
+	if (desc->opts_mutex)
+		mutex_unlock(desc->opts_mutex);
+	return ret;
+}
+
+static ssize_t ext_prop_data_show(struct config_item *item, char *page)
+{
+	struct usb_os_desc_ext_prop *ext_prop = to_usb_os_desc_ext_prop(item);
+	int len = ext_prop->data_len;
+
+	if (ext_prop->type == USB_EXT_PROP_UNICODE ||
+	    ext_prop->type == USB_EXT_PROP_UNICODE_ENV ||
+	    ext_prop->type == USB_EXT_PROP_UNICODE_LINK)
+		len >>= 1;
+	memcpy(page, ext_prop->data, len);
+
+	return len;
+}
+
+static ssize_t ext_prop_data_store(struct config_item *item,
+				   const char *page, size_t len)
+{
+	struct usb_os_desc_ext_prop *ext_prop = to_usb_os_desc_ext_prop(item);
+	struct usb_os_desc *desc = to_usb_os_desc(ext_prop->item.ci_parent);
+	char *new_data;
+	size_t ret_len = len;
+
+	if (page[len - 1] == '\n' || page[len - 1] == '\0')
+		--len;
+	new_data = kmemdup(page, len, GFP_KERNEL);
+	if (!new_data)
+		return -ENOMEM;
+
+	if (desc->opts_mutex)
+		mutex_lock(desc->opts_mutex);
+	kfree(ext_prop->data);
+	ext_prop->data = new_data;
+	desc->ext_prop_len -= ext_prop->data_len;
+	ext_prop->data_len = len;
+	desc->ext_prop_len += ext_prop->data_len;
+	if (ext_prop->type == USB_EXT_PROP_UNICODE ||
+	    ext_prop->type == USB_EXT_PROP_UNICODE_ENV ||
+	    ext_prop->type == USB_EXT_PROP_UNICODE_LINK) {
+		desc->ext_prop_len -= ext_prop->data_len;
+		ext_prop->data_len <<= 1;
+		ext_prop->data_len += 2;
+		desc->ext_prop_len += ext_prop->data_len;
+	}
+	if (desc->opts_mutex)
+		mutex_unlock(desc->opts_mutex);
+	return ret_len;
+}
+
+CONFIGFS_ATTR(ext_prop_, type);
+CONFIGFS_ATTR(ext_prop_, data);
+
+static struct configfs_attribute *ext_prop_attrs[] = {
+	&ext_prop_attr_type,
+	&ext_prop_attr_data,
+	NULL,
+};
+
+static void usb_os_desc_ext_prop_release(struct config_item *item)
+{
+	struct usb_os_desc_ext_prop *ext_prop = to_usb_os_desc_ext_prop(item);
+
+	kfree(ext_prop); /* frees a whole chunk */
+}
+
+static struct configfs_item_operations ext_prop_ops = {
+	.release		= usb_os_desc_ext_prop_release,
+};
+
+static struct config_item *ext_prop_make(
+		struct config_group *group,
+		const char *name)
+{
+	struct usb_os_desc_ext_prop *ext_prop;
+	struct config_item_type *ext_prop_type;
+	struct usb_os_desc *desc;
+	char *vlabuf;
+
+	vla_group(data_chunk);
+	vla_item(data_chunk, struct usb_os_desc_ext_prop, ext_prop, 1);
+	vla_item(data_chunk, struct config_item_type, ext_prop_type, 1);
+
+	vlabuf = kzalloc(vla_group_size(data_chunk), GFP_KERNEL);
+	if (!vlabuf)
+		return ERR_PTR(-ENOMEM);
+
+	ext_prop = vla_ptr(vlabuf, data_chunk, ext_prop);
+	ext_prop_type = vla_ptr(vlabuf, data_chunk, ext_prop_type);
+
+	desc = container_of(group, struct usb_os_desc, group);
+	ext_prop_type->ct_item_ops = &ext_prop_ops;
+	ext_prop_type->ct_attrs = ext_prop_attrs;
+	ext_prop_type->ct_owner = desc->owner;
+
+	config_item_init_type_name(&ext_prop->item, name, ext_prop_type);
+
+	ext_prop->name = kstrdup(name, GFP_KERNEL);
+	if (!ext_prop->name) {
+		kfree(vlabuf);
+		return ERR_PTR(-ENOMEM);
+	}
+	desc->ext_prop_len += 14;
+	ext_prop->name_len = 2 * strlen(ext_prop->name) + 2;
+	if (desc->opts_mutex)
+		mutex_lock(desc->opts_mutex);
+	desc->ext_prop_len += ext_prop->name_len;
+	list_add_tail(&ext_prop->entry, &desc->ext_prop);
+	++desc->ext_prop_count;
+	if (desc->opts_mutex)
+		mutex_unlock(desc->opts_mutex);
+
+	return &ext_prop->item;
+}
+
+static void ext_prop_drop(struct config_group *group, struct config_item *item)
+{
+	struct usb_os_desc_ext_prop *ext_prop = to_usb_os_desc_ext_prop(item);
+	struct usb_os_desc *desc = to_usb_os_desc(&group->cg_item);
+
+	if (desc->opts_mutex)
+		mutex_lock(desc->opts_mutex);
+	list_del(&ext_prop->entry);
+	--desc->ext_prop_count;
+	kfree(ext_prop->name);
+	desc->ext_prop_len -= (ext_prop->name_len + ext_prop->data_len + 14);
+	if (desc->opts_mutex)
+		mutex_unlock(desc->opts_mutex);
+	config_item_put(item);
+}
+
+static struct configfs_group_operations interf_grp_ops = {
+	.make_item	= &ext_prop_make,
+	.drop_item	= &ext_prop_drop,
+};
+
+static ssize_t interf_grp_compatible_id_show(struct config_item *item,
+					     char *page)
+{
+	memcpy(page, to_usb_os_desc(item)->ext_compat_id, 8);
+	return 8;
+}
+
+static ssize_t interf_grp_compatible_id_store(struct config_item *item,
+					      const char *page, size_t len)
+{
+	struct usb_os_desc *desc = to_usb_os_desc(item);
+	int l;
+
+	l = min_t(int, 8, len);
+	if (page[l - 1] == '\n')
+		--l;
+	if (desc->opts_mutex)
+		mutex_lock(desc->opts_mutex);
+	memcpy(desc->ext_compat_id, page, l);
+
+	if (desc->opts_mutex)
+		mutex_unlock(desc->opts_mutex);
+
+	return len;
+}
+
+static ssize_t interf_grp_sub_compatible_id_show(struct config_item *item,
+						 char *page)
+{
+	memcpy(page, to_usb_os_desc(item)->ext_compat_id + 8, 8);
+	return 8;
+}
+
+static ssize_t interf_grp_sub_compatible_id_store(struct config_item *item,
+						  const char *page, size_t len)
+{
+	struct usb_os_desc *desc = to_usb_os_desc(item);
+	int l;
+
+	l = min_t(int, 8, len);
+	if (page[l - 1] == '\n')
+		--l;
+	if (desc->opts_mutex)
+		mutex_lock(desc->opts_mutex);
+	memcpy(desc->ext_compat_id + 8, page, l);
+
+	if (desc->opts_mutex)
+		mutex_unlock(desc->opts_mutex);
+
+	return len;
+}
+
+CONFIGFS_ATTR(interf_grp_, compatible_id);
+CONFIGFS_ATTR(interf_grp_, sub_compatible_id);
+
+static struct configfs_attribute *interf_grp_attrs[] = {
+	&interf_grp_attr_compatible_id,
+	&interf_grp_attr_sub_compatible_id,
+	NULL
+};
+
+struct config_group *usb_os_desc_prepare_interf_dir(
+		struct config_group *parent,
+		int n_interf,
+		struct usb_os_desc **desc,
+		char **names,
+		struct module *owner)
+{
+	struct config_group *os_desc_group;
+	struct config_item_type *os_desc_type, *interface_type;
+
+	vla_group(data_chunk);
+	vla_item(data_chunk, struct config_group, os_desc_group, 1);
+	vla_item(data_chunk, struct config_item_type, os_desc_type, 1);
+	vla_item(data_chunk, struct config_item_type, interface_type, 1);
+
+	char *vlabuf = kzalloc(vla_group_size(data_chunk), GFP_KERNEL);
+	if (!vlabuf)
+		return ERR_PTR(-ENOMEM);
+
+	os_desc_group = vla_ptr(vlabuf, data_chunk, os_desc_group);
+	os_desc_type = vla_ptr(vlabuf, data_chunk, os_desc_type);
+	interface_type = vla_ptr(vlabuf, data_chunk, interface_type);
+
+	os_desc_type->ct_owner = owner;
+	config_group_init_type_name(os_desc_group, "os_desc", os_desc_type);
+	configfs_add_default_group(os_desc_group, parent);
+
+	interface_type->ct_group_ops = &interf_grp_ops;
+	interface_type->ct_attrs = interf_grp_attrs;
+	interface_type->ct_owner = owner;
+
+	while (n_interf--) {
+		struct usb_os_desc *d;
+
+		d = desc[n_interf];
+		d->owner = owner;
+		config_group_init_type_name(&d->group, "", interface_type);
+		config_item_set_name(&d->group.cg_item, "interface.%s",
+				     names[n_interf]);
+		configfs_add_default_group(&d->group, os_desc_group);
+	}
+
+	return os_desc_group;
+}
+EXPORT_SYMBOL(usb_os_desc_prepare_interf_dir);
+
+static int configfs_do_nothing(struct usb_composite_dev *cdev)
+{
+	WARN_ON(1);
+	return -EINVAL;
+}
+
+int composite_dev_prepare(struct usb_composite_driver *composite,
+		struct usb_composite_dev *dev);
+
+int composite_os_desc_req_prepare(struct usb_composite_dev *cdev,
+				  struct usb_ep *ep0);
+
+static void purge_configs_funcs(struct gadget_info *gi)
+{
+	struct usb_configuration	*c;
+
+	list_for_each_entry(c, &gi->cdev.configs, list) {
+		struct usb_function *f, *tmp;
+		struct config_usb_cfg *cfg;
+
+		cfg = container_of(c, struct config_usb_cfg, c);
+
+		list_for_each_entry_safe_reverse(f, tmp, &c->functions, list) {
+
+			list_move(&f->list, &cfg->func_list);
+			if (f->unbind) {
+				dev_dbg(&gi->cdev.gadget->dev,
+					"unbind function '%s'/%p\n",
+					f->name, f);
+				f->unbind(c, f);
+			}
+		}
+		c->next_interface_id = 0;
+		memset(c->interface, 0, sizeof(c->interface));
+		c->superspeed_plus = 0;
+		c->superspeed = 0;
+		c->highspeed = 0;
+		c->fullspeed = 0;
+	}
+}
+
+static int configfs_composite_bind(struct usb_gadget *gadget,
+		struct usb_gadget_driver *gdriver)
+{
+	struct usb_composite_driver     *composite = to_cdriver(gdriver);
+	struct gadget_info		*gi = container_of(composite,
+						struct gadget_info, composite);
+	struct usb_composite_dev	*cdev = &gi->cdev;
+	struct usb_configuration	*c;
+	struct usb_string		*s;
+	unsigned			i;
+	int				ret;
+
+	/* the gi->lock is hold by the caller */
+	gi->unbind = 0;
+	cdev->gadget = gadget;
+	set_gadget_data(gadget, cdev);
+	ret = composite_dev_prepare(composite, cdev);
+	if (ret)
+		return ret;
+	/* and now the gadget bind */
+	ret = -EINVAL;
+
+	if (list_empty(&gi->cdev.configs)) {
+		pr_err("Need at least one configuration in %s.\n",
+				gi->composite.name);
+		goto err_comp_cleanup;
+	}
+
+
+	list_for_each_entry(c, &gi->cdev.configs, list) {
+		struct config_usb_cfg *cfg;
+
+		cfg = container_of(c, struct config_usb_cfg, c);
+		if (list_empty(&cfg->func_list)) {
+			pr_err("Config %s/%d of %s needs at least one function.\n",
+			      c->label, c->bConfigurationValue,
+			      gi->composite.name);
+			goto err_comp_cleanup;
+		}
+	}
+
+	/* init all strings */
+	if (!list_empty(&gi->string_list)) {
+		struct gadget_strings *gs;
+
+		i = 0;
+		list_for_each_entry(gs, &gi->string_list, list) {
+
+			gi->gstrings[i] = &gs->stringtab_dev;
+			gs->stringtab_dev.strings = gs->strings;
+			gs->strings[USB_GADGET_MANUFACTURER_IDX].s =
+				gs->manufacturer;
+			gs->strings[USB_GADGET_PRODUCT_IDX].s = gs->product;
+			gs->strings[USB_GADGET_SERIAL_IDX].s = gs->serialnumber;
+			i++;
+		}
+		gi->gstrings[i] = NULL;
+		s = usb_gstrings_attach(&gi->cdev, gi->gstrings,
+				USB_GADGET_FIRST_AVAIL_IDX);
+		if (IS_ERR(s)) {
+			ret = PTR_ERR(s);
+			goto err_comp_cleanup;
+		}
+
+		gi->cdev.desc.iManufacturer = s[USB_GADGET_MANUFACTURER_IDX].id;
+		gi->cdev.desc.iProduct = s[USB_GADGET_PRODUCT_IDX].id;
+		gi->cdev.desc.iSerialNumber = s[USB_GADGET_SERIAL_IDX].id;
+	}
+
+	if (gi->use_os_desc) {
+		cdev->use_os_string = true;
+		cdev->b_vendor_code = gi->b_vendor_code;
+		memcpy(cdev->qw_sign, gi->qw_sign, OS_STRING_QW_SIGN_LEN);
+	}
+
+	if (gadget_is_otg(gadget) && !otg_desc[0]) {
+		struct usb_descriptor_header *usb_desc;
+
+		usb_desc = usb_otg_descriptor_alloc(gadget);
+		if (!usb_desc) {
+			ret = -ENOMEM;
+			goto err_comp_cleanup;
+		}
+		usb_otg_descriptor_init(gadget, usb_desc);
+		otg_desc[0] = usb_desc;
+		otg_desc[1] = NULL;
+	}
+
+	/* Go through all configs, attach all functions */
+	list_for_each_entry(c, &gi->cdev.configs, list) {
+		struct config_usb_cfg *cfg;
+		struct usb_function *f;
+		struct usb_function *tmp;
+		struct gadget_config_name *cn;
+
+		if (gadget_is_otg(gadget))
+			c->descriptors = otg_desc;
+
+		cfg = container_of(c, struct config_usb_cfg, c);
+		if (!list_empty(&cfg->string_list)) {
+			i = 0;
+			list_for_each_entry(cn, &cfg->string_list, list) {
+				cfg->gstrings[i] = &cn->stringtab_dev;
+				cn->stringtab_dev.strings = &cn->strings;
+				cn->strings.s = cn->configuration;
+				i++;
+			}
+			cfg->gstrings[i] = NULL;
+			s = usb_gstrings_attach(&gi->cdev, cfg->gstrings, 1);
+			if (IS_ERR(s)) {
+				ret = PTR_ERR(s);
+				goto err_comp_cleanup;
+			}
+			c->iConfiguration = s[0].id;
+		}
+
+		list_for_each_entry_safe(f, tmp, &cfg->func_list, list) {
+			list_del(&f->list);
+			ret = usb_add_function(c, f);
+			if (ret) {
+				list_add(&f->list, &cfg->func_list);
+				goto err_purge_funcs;
+			}
+		}
+		ret = usb_gadget_check_config(cdev->gadget);
+		if (ret)
+			goto err_purge_funcs;
+
+		usb_ep_autoconfig_reset(cdev->gadget);
+	}
+	if (cdev->use_os_string) {
+		ret = composite_os_desc_req_prepare(cdev, gadget->ep0);
+		if (ret)
+			goto err_purge_funcs;
+	}
+
+	usb_ep_autoconfig_reset(cdev->gadget);
+	return 0;
+
+err_purge_funcs:
+	purge_configs_funcs(gi);
+err_comp_cleanup:
+	composite_dev_cleanup(cdev);
+	return ret;
+}
+
+static void configfs_composite_unbind(struct usb_gadget *gadget)
+{
+	struct usb_composite_dev	*cdev;
+	struct gadget_info		*gi;
+	unsigned long flags;
+
+	/* the gi->lock is hold by the caller */
+
+	cdev = get_gadget_data(gadget);
+	gi = container_of(cdev, struct gadget_info, cdev);
+	spin_lock_irqsave(&gi->spinlock, flags);
+	gi->unbind = 1;
+	spin_unlock_irqrestore(&gi->spinlock, flags);
+
+	kfree(otg_desc[0]);
+	otg_desc[0] = NULL;
+	purge_configs_funcs(gi);
+	composite_dev_cleanup(cdev);
+	usb_ep_autoconfig_reset(cdev->gadget);
+	spin_lock_irqsave(&gi->spinlock, flags);
+	cdev->gadget = NULL;
+	cdev->deactivations = 0;
+	gadget->deactivated = false;
+	set_gadget_data(gadget, NULL);
+	spin_unlock_irqrestore(&gi->spinlock, flags);
+}
+
+static int configfs_composite_setup(struct usb_gadget *gadget,
+		const struct usb_ctrlrequest *ctrl)
+{
+	struct usb_composite_dev *cdev;
+	struct gadget_info *gi;
+	unsigned long flags;
+	int ret;
+
+	cdev = get_gadget_data(gadget);
+	if (!cdev)
+		return 0;
+
+	gi = container_of(cdev, struct gadget_info, cdev);
+	spin_lock_irqsave(&gi->spinlock, flags);
+	cdev = get_gadget_data(gadget);
+	if (!cdev || gi->unbind) {
+		spin_unlock_irqrestore(&gi->spinlock, flags);
+		return 0;
+	}
+
+	ret = composite_setup(gadget, ctrl);
+	spin_unlock_irqrestore(&gi->spinlock, flags);
+	return ret;
+}
+
+static void configfs_composite_disconnect(struct usb_gadget *gadget)
+{
+	struct usb_composite_dev *cdev;
+	struct gadget_info *gi;
+	unsigned long flags;
+
+	cdev = get_gadget_data(gadget);
+	if (!cdev)
+		return;
+
+	gi = container_of(cdev, struct gadget_info, cdev);
+	spin_lock_irqsave(&gi->spinlock, flags);
+	cdev = get_gadget_data(gadget);
+	if (!cdev || gi->unbind) {
+		spin_unlock_irqrestore(&gi->spinlock, flags);
+		return;
+	}
+
+	composite_disconnect(gadget);
+	spin_unlock_irqrestore(&gi->spinlock, flags);
+}
+
+static void configfs_composite_reset(struct usb_gadget *gadget)
+{
+	struct usb_composite_dev *cdev;
+	struct gadget_info *gi;
+	unsigned long flags;
+
+	cdev = get_gadget_data(gadget);
+	if (!cdev)
+		return;
+
+	gi = container_of(cdev, struct gadget_info, cdev);
+	spin_lock_irqsave(&gi->spinlock, flags);
+	cdev = get_gadget_data(gadget);
+	if (!cdev || gi->unbind) {
+		spin_unlock_irqrestore(&gi->spinlock, flags);
+		return;
+	}
+
+	composite_reset(gadget);
+	spin_unlock_irqrestore(&gi->spinlock, flags);
+}
+
+static void configfs_composite_suspend(struct usb_gadget *gadget)
+{
+	struct usb_composite_dev *cdev;
+	struct gadget_info *gi;
+	unsigned long flags;
+
+	cdev = get_gadget_data(gadget);
+	if (!cdev)
+		return;
+
+	gi = container_of(cdev, struct gadget_info, cdev);
+	spin_lock_irqsave(&gi->spinlock, flags);
+	cdev = get_gadget_data(gadget);
+	if (!cdev || gi->unbind) {
+		spin_unlock_irqrestore(&gi->spinlock, flags);
+		return;
+	}
+
+	composite_suspend(gadget);
+	spin_unlock_irqrestore(&gi->spinlock, flags);
+}
+
+static void configfs_composite_resume(struct usb_gadget *gadget)
+{
+	struct usb_composite_dev *cdev;
+	struct gadget_info *gi;
+	unsigned long flags;
+
+	cdev = get_gadget_data(gadget);
+	if (!cdev)
+		return;
+
+	gi = container_of(cdev, struct gadget_info, cdev);
+	spin_lock_irqsave(&gi->spinlock, flags);
+	cdev = get_gadget_data(gadget);
+	if (!cdev || gi->unbind) {
+		spin_unlock_irqrestore(&gi->spinlock, flags);
+		return;
+	}
+
+	composite_resume(gadget);
+	spin_unlock_irqrestore(&gi->spinlock, flags);
+}
+
+static const struct usb_gadget_driver configfs_driver_template = {
+	.bind           = configfs_composite_bind,
+	.unbind         = configfs_composite_unbind,
+
+	.setup          = configfs_composite_setup,
+	.reset          = configfs_composite_reset,
+	.disconnect     = configfs_composite_disconnect,
+
+	.suspend	= configfs_composite_suspend,
+	.resume		= configfs_composite_resume,
+
+	.max_speed	= USB_SPEED_SUPER_PLUS,
+	.driver = {
+		.owner          = THIS_MODULE,
+	},
+	.match_existing_only = 1,
+};
+
+static struct config_group *gadgets_make(
+		struct config_group *group,
+		const char *name)
+{
+	struct gadget_info *gi;
+
+	gi = kzalloc(sizeof(*gi), GFP_KERNEL);
+	if (!gi)
+		return ERR_PTR(-ENOMEM);
+
+	config_group_init_type_name(&gi->group, name, &gadget_root_type);
+
+	config_group_init_type_name(&gi->functions_group, "functions",
+			&functions_type);
+	configfs_add_default_group(&gi->functions_group, &gi->group);
+
+	config_group_init_type_name(&gi->configs_group, "configs",
+			&config_desc_type);
+	configfs_add_default_group(&gi->configs_group, &gi->group);
+
+	config_group_init_type_name(&gi->strings_group, "strings",
+			&gadget_strings_strings_type);
+	configfs_add_default_group(&gi->strings_group, &gi->group);
+
+	config_group_init_type_name(&gi->os_desc_group, "os_desc",
+			&os_desc_type);
+	configfs_add_default_group(&gi->os_desc_group, &gi->group);
+
+	gi->composite.bind = configfs_do_nothing;
+	gi->composite.unbind = configfs_do_nothing;
+	gi->composite.suspend = NULL;
+	gi->composite.resume = NULL;
+	gi->composite.max_speed = USB_SPEED_SUPER_PLUS;
+
+	spin_lock_init(&gi->spinlock);
+	mutex_init(&gi->lock);
+	INIT_LIST_HEAD(&gi->string_list);
+	INIT_LIST_HEAD(&gi->available_func);
+
+	composite_init_dev(&gi->cdev);
+	gi->cdev.desc.bLength = USB_DT_DEVICE_SIZE;
+	gi->cdev.desc.bDescriptorType = USB_DT_DEVICE;
+	gi->cdev.desc.bcdDevice = cpu_to_le16(get_default_bcdDevice());
+
+	gi->composite.gadget_driver = configfs_driver_template;
+
+	gi->composite.gadget_driver.driver.name = kasprintf(GFP_KERNEL,
+							    "configfs-gadget.%s", name);
+	if (!gi->composite.gadget_driver.driver.name)
+		goto err;
+
+	gi->composite.gadget_driver.function = kstrdup(name, GFP_KERNEL);
+	gi->composite.name = gi->composite.gadget_driver.function;
+
+	if (!gi->composite.gadget_driver.function)
+		goto out_free_driver_name;
+
+	return &gi->group;
+
+out_free_driver_name:
+	kfree(gi->composite.gadget_driver.driver.name);
+err:
+	kfree(gi);
+	return ERR_PTR(-ENOMEM);
+}
+
+static void gadgets_drop(struct config_group *group, struct config_item *item)
+{
+	config_item_put(item);
+}
+
+static struct configfs_group_operations gadgets_ops = {
+	.make_group     = &gadgets_make,
+	.drop_item      = &gadgets_drop,
+};
+
+static const struct config_item_type gadgets_type = {
+	.ct_group_ops   = &gadgets_ops,
+	.ct_owner       = THIS_MODULE,
+};
+
+static struct configfs_subsystem gadget_subsys = {
+	.su_group = {
+		.cg_item = {
+			.ci_namebuf = "usb_gadget",
+			.ci_type = &gadgets_type,
+		},
+	},
+	.su_mutex = __MUTEX_INITIALIZER(gadget_subsys.su_mutex),
+};
+
+void unregister_gadget_item(struct config_item *item)
+{
+	struct gadget_info *gi = to_gadget_info(item);
+
+	mutex_lock(&gi->lock);
+	unregister_gadget(gi);
+	mutex_unlock(&gi->lock);
+}
+EXPORT_SYMBOL_GPL(unregister_gadget_item);
+
+static int __init gadget_cfs_init(void)
+{
+	int ret;
+
+	config_group_init(&gadget_subsys.su_group);
+
+	ret = configfs_register_subsystem(&gadget_subsys);
+	return ret;
+}
+module_init(gadget_cfs_init);
+
+static void __exit gadget_cfs_exit(void)
+{
+	configfs_unregister_subsystem(&gadget_subsys);
+}
+module_exit(gadget_cfs_exit);