v4.19.13 snapshot.
diff --git a/drivers/usb/gadget/legacy/zero.c b/drivers/usb/gadget/legacy/zero.c
new file mode 100644
index 0000000..6e84b44
--- /dev/null
+++ b/drivers/usb/gadget/legacy/zero.c
@@ -0,0 +1,428 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * zero.c -- Gadget Zero, for USB development
+ *
+ * Copyright (C) 2003-2008 David Brownell
+ * Copyright (C) 2008 by Nokia Corporation
+ */
+
+/*
+ * Gadget Zero only needs two bulk endpoints, and is an example of how you
+ * can write a hardware-agnostic gadget driver running inside a USB device.
+ * Some hardware details are visible, but don't affect most of the driver.
+ *
+ * Use it with the Linux host/master side "usbtest" driver to get a basic
+ * functional test of your device-side usb stack, or with "usb-skeleton".
+ *
+ * It supports two similar configurations.  One sinks whatever the usb host
+ * writes, and in return sources zeroes.  The other loops whatever the host
+ * writes back, so the host can read it.
+ *
+ * Many drivers will only have one configuration, letting them be much
+ * simpler if they also don't support high speed operation (like this
+ * driver does).
+ *
+ * Why is *this* driver using two configurations, rather than setting up
+ * two interfaces with different functions?  To help verify that multiple
+ * configuration infrastructure is working correctly; also, so that it can
+ * work with low capability USB controllers without four bulk endpoints.
+ */
+
+/*
+ * driver assumes self-powered hardware, and
+ * has no way for users to trigger remote wakeup.
+ */
+
+/* #define VERBOSE_DEBUG */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/usb/composite.h>
+
+#include "g_zero.h"
+/*-------------------------------------------------------------------------*/
+USB_GADGET_COMPOSITE_OPTIONS();
+
+#define DRIVER_VERSION		"Cinco de Mayo 2008"
+
+static const char longname[] = "Gadget Zero";
+
+/*
+ * Normally the "loopback" configuration is second (index 1) so
+ * it's not the default.  Here's where to change that order, to
+ * work better with hosts where config changes are problematic or
+ * controllers (like original superh) that only support one config.
+ */
+static bool loopdefault = 0;
+module_param(loopdefault, bool, S_IRUGO|S_IWUSR);
+
+static struct usb_zero_options gzero_options = {
+	.isoc_interval = GZERO_ISOC_INTERVAL,
+	.isoc_maxpacket = GZERO_ISOC_MAXPACKET,
+	.bulk_buflen = GZERO_BULK_BUFLEN,
+	.qlen = GZERO_QLEN,
+	.ss_bulk_qlen = GZERO_SS_BULK_QLEN,
+	.ss_iso_qlen = GZERO_SS_ISO_QLEN,
+};
+
+/*-------------------------------------------------------------------------*/
+
+/* Thanks to NetChip Technologies for donating this product ID.
+ *
+ * DO NOT REUSE THESE IDs with a protocol-incompatible driver!!  Ever!!
+ * Instead:  allocate your own, using normal USB-IF procedures.
+ */
+#ifndef	CONFIG_USB_ZERO_HNPTEST
+#define DRIVER_VENDOR_NUM	0x0525		/* NetChip */
+#define DRIVER_PRODUCT_NUM	0xa4a0		/* Linux-USB "Gadget Zero" */
+#define DEFAULT_AUTORESUME	0
+#else
+#define DRIVER_VENDOR_NUM	0x1a0a		/* OTG test device IDs */
+#define DRIVER_PRODUCT_NUM	0xbadd
+#define DEFAULT_AUTORESUME	5
+#endif
+
+/* If the optional "autoresume" mode is enabled, it provides good
+ * functional coverage for the "USBCV" test harness from USB-IF.
+ * It's always set if OTG mode is enabled.
+ */
+static unsigned autoresume = DEFAULT_AUTORESUME;
+module_param(autoresume, uint, S_IRUGO);
+MODULE_PARM_DESC(autoresume, "zero, or seconds before remote wakeup");
+
+/* Maximum Autoresume time */
+static unsigned max_autoresume;
+module_param(max_autoresume, uint, S_IRUGO);
+MODULE_PARM_DESC(max_autoresume, "maximum seconds before remote wakeup");
+
+/* Interval between two remote wakeups */
+static unsigned autoresume_interval_ms;
+module_param(autoresume_interval_ms, uint, S_IRUGO);
+MODULE_PARM_DESC(autoresume_interval_ms,
+		"milliseconds to increase successive wakeup delays");
+
+static unsigned autoresume_step_ms;
+/*-------------------------------------------------------------------------*/
+
+static struct usb_device_descriptor device_desc = {
+	.bLength =		sizeof device_desc,
+	.bDescriptorType =	USB_DT_DEVICE,
+
+	/* .bcdUSB = DYNAMIC */
+	.bDeviceClass =		USB_CLASS_VENDOR_SPEC,
+
+	.idVendor =		cpu_to_le16(DRIVER_VENDOR_NUM),
+	.idProduct =		cpu_to_le16(DRIVER_PRODUCT_NUM),
+	.bNumConfigurations =	2,
+};
+
+static const struct usb_descriptor_header *otg_desc[2];
+
+/* string IDs are assigned dynamically */
+/* default serial number takes at least two packets */
+static char serial[] = "0123456789.0123456789.0123456789";
+
+#define USB_GZERO_SS_DESC	(USB_GADGET_FIRST_AVAIL_IDX + 0)
+#define USB_GZERO_LB_DESC	(USB_GADGET_FIRST_AVAIL_IDX + 1)
+
+static struct usb_string strings_dev[] = {
+	[USB_GADGET_MANUFACTURER_IDX].s = "",
+	[USB_GADGET_PRODUCT_IDX].s = longname,
+	[USB_GADGET_SERIAL_IDX].s = serial,
+	[USB_GZERO_SS_DESC].s	= "source and sink data",
+	[USB_GZERO_LB_DESC].s	= "loop input to output",
+	{  }			/* end of list */
+};
+
+static struct usb_gadget_strings stringtab_dev = {
+	.language	= 0x0409,	/* en-us */
+	.strings	= strings_dev,
+};
+
+static struct usb_gadget_strings *dev_strings[] = {
+	&stringtab_dev,
+	NULL,
+};
+
+/*-------------------------------------------------------------------------*/
+
+static struct timer_list	autoresume_timer;
+static struct usb_composite_dev *autoresume_cdev;
+
+static void zero_autoresume(struct timer_list *unused)
+{
+	struct usb_composite_dev	*cdev = autoresume_cdev;
+	struct usb_gadget		*g = cdev->gadget;
+
+	/* unconfigured devices can't issue wakeups */
+	if (!cdev->config)
+		return;
+
+	/* Normally the host would be woken up for something
+	 * more significant than just a timer firing; likely
+	 * because of some direct user request.
+	 */
+	if (g->speed != USB_SPEED_UNKNOWN) {
+		int status = usb_gadget_wakeup(g);
+		INFO(cdev, "%s --> %d\n", __func__, status);
+	}
+}
+
+static void zero_suspend(struct usb_composite_dev *cdev)
+{
+	if (cdev->gadget->speed == USB_SPEED_UNKNOWN)
+		return;
+
+	if (autoresume) {
+		if (max_autoresume &&
+			(autoresume_step_ms > max_autoresume * 1000))
+				autoresume_step_ms = autoresume * 1000;
+
+		mod_timer(&autoresume_timer, jiffies +
+			msecs_to_jiffies(autoresume_step_ms));
+		DBG(cdev, "suspend, wakeup in %d milliseconds\n",
+			autoresume_step_ms);
+
+		autoresume_step_ms += autoresume_interval_ms;
+	} else
+		DBG(cdev, "%s\n", __func__);
+}
+
+static void zero_resume(struct usb_composite_dev *cdev)
+{
+	DBG(cdev, "%s\n", __func__);
+	del_timer(&autoresume_timer);
+}
+
+/*-------------------------------------------------------------------------*/
+
+static struct usb_configuration loopback_driver = {
+	.label          = "loopback",
+	.bConfigurationValue = 2,
+	.bmAttributes   = USB_CONFIG_ATT_SELFPOWER,
+	/* .iConfiguration = DYNAMIC */
+};
+
+static struct usb_function *func_ss;
+static struct usb_function_instance *func_inst_ss;
+
+static int ss_config_setup(struct usb_configuration *c,
+		const struct usb_ctrlrequest *ctrl)
+{
+	switch (ctrl->bRequest) {
+	case 0x5b:
+	case 0x5c:
+		return func_ss->setup(func_ss, ctrl);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static struct usb_configuration sourcesink_driver = {
+	.label                  = "source/sink",
+	.setup                  = ss_config_setup,
+	.bConfigurationValue    = 3,
+	.bmAttributes           = USB_CONFIG_ATT_SELFPOWER,
+	/* .iConfiguration      = DYNAMIC */
+};
+
+module_param_named(buflen, gzero_options.bulk_buflen, uint, 0);
+module_param_named(pattern, gzero_options.pattern, uint, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(pattern, "0 = all zeroes, 1 = mod63, 2 = none");
+
+module_param_named(isoc_interval, gzero_options.isoc_interval, uint,
+		S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(isoc_interval, "1 - 16");
+
+module_param_named(isoc_maxpacket, gzero_options.isoc_maxpacket, uint,
+		S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(isoc_maxpacket, "0 - 1023 (fs), 0 - 1024 (hs/ss)");
+
+module_param_named(isoc_mult, gzero_options.isoc_mult, uint, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(isoc_mult, "0 - 2 (hs/ss only)");
+
+module_param_named(isoc_maxburst, gzero_options.isoc_maxburst, uint,
+		S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(isoc_maxburst, "0 - 15 (ss only)");
+
+static struct usb_function *func_lb;
+static struct usb_function_instance *func_inst_lb;
+
+module_param_named(qlen, gzero_options.qlen, uint, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(qlen, "depth of loopback queue");
+
+module_param_named(ss_bulk_qlen, gzero_options.ss_bulk_qlen, uint,
+		S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(bulk_qlen, "depth of sourcesink queue for bulk transfer");
+
+module_param_named(ss_iso_qlen, gzero_options.ss_iso_qlen, uint,
+		S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(iso_qlen, "depth of sourcesink queue for iso transfer");
+
+static int zero_bind(struct usb_composite_dev *cdev)
+{
+	struct f_ss_opts	*ss_opts;
+	struct f_lb_opts	*lb_opts;
+	int			status;
+
+	/* Allocate string descriptor numbers ... note that string
+	 * contents can be overridden by the composite_dev glue.
+	 */
+	status = usb_string_ids_tab(cdev, strings_dev);
+	if (status < 0)
+		return status;
+
+	device_desc.iManufacturer = strings_dev[USB_GADGET_MANUFACTURER_IDX].id;
+	device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
+	device_desc.iSerialNumber = strings_dev[USB_GADGET_SERIAL_IDX].id;
+
+	autoresume_cdev = cdev;
+	timer_setup(&autoresume_timer, zero_autoresume, 0);
+
+	func_inst_ss = usb_get_function_instance("SourceSink");
+	if (IS_ERR(func_inst_ss))
+		return PTR_ERR(func_inst_ss);
+
+	ss_opts =  container_of(func_inst_ss, struct f_ss_opts, func_inst);
+	ss_opts->pattern = gzero_options.pattern;
+	ss_opts->isoc_interval = gzero_options.isoc_interval;
+	ss_opts->isoc_maxpacket = gzero_options.isoc_maxpacket;
+	ss_opts->isoc_mult = gzero_options.isoc_mult;
+	ss_opts->isoc_maxburst = gzero_options.isoc_maxburst;
+	ss_opts->bulk_buflen = gzero_options.bulk_buflen;
+	ss_opts->bulk_qlen = gzero_options.ss_bulk_qlen;
+	ss_opts->iso_qlen = gzero_options.ss_iso_qlen;
+
+	func_ss = usb_get_function(func_inst_ss);
+	if (IS_ERR(func_ss)) {
+		status = PTR_ERR(func_ss);
+		goto err_put_func_inst_ss;
+	}
+
+	func_inst_lb = usb_get_function_instance("Loopback");
+	if (IS_ERR(func_inst_lb)) {
+		status = PTR_ERR(func_inst_lb);
+		goto err_put_func_ss;
+	}
+
+	lb_opts = container_of(func_inst_lb, struct f_lb_opts, func_inst);
+	lb_opts->bulk_buflen = gzero_options.bulk_buflen;
+	lb_opts->qlen = gzero_options.qlen;
+
+	func_lb = usb_get_function(func_inst_lb);
+	if (IS_ERR(func_lb)) {
+		status = PTR_ERR(func_lb);
+		goto err_put_func_inst_lb;
+	}
+
+	sourcesink_driver.iConfiguration = strings_dev[USB_GZERO_SS_DESC].id;
+	loopback_driver.iConfiguration = strings_dev[USB_GZERO_LB_DESC].id;
+
+	/* support autoresume for remote wakeup testing */
+	sourcesink_driver.bmAttributes &= ~USB_CONFIG_ATT_WAKEUP;
+	loopback_driver.bmAttributes &= ~USB_CONFIG_ATT_WAKEUP;
+	sourcesink_driver.descriptors = NULL;
+	loopback_driver.descriptors = NULL;
+	if (autoresume) {
+		sourcesink_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
+		loopback_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
+		autoresume_step_ms = autoresume * 1000;
+	}
+
+	/* support OTG systems */
+	if (gadget_is_otg(cdev->gadget)) {
+		if (!otg_desc[0]) {
+			struct usb_descriptor_header *usb_desc;
+
+			usb_desc = usb_otg_descriptor_alloc(cdev->gadget);
+			if (!usb_desc) {
+				status = -ENOMEM;
+				goto err_conf_flb;
+			}
+			usb_otg_descriptor_init(cdev->gadget, usb_desc);
+			otg_desc[0] = usb_desc;
+			otg_desc[1] = NULL;
+		}
+		sourcesink_driver.descriptors = otg_desc;
+		sourcesink_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
+		loopback_driver.descriptors = otg_desc;
+		loopback_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
+	}
+
+	/* Register primary, then secondary configuration.  Note that
+	 * SH3 only allows one config...
+	 */
+	if (loopdefault) {
+		usb_add_config_only(cdev, &loopback_driver);
+		usb_add_config_only(cdev, &sourcesink_driver);
+	} else {
+		usb_add_config_only(cdev, &sourcesink_driver);
+		usb_add_config_only(cdev, &loopback_driver);
+	}
+	status = usb_add_function(&sourcesink_driver, func_ss);
+	if (status)
+		goto err_free_otg_desc;
+
+	usb_ep_autoconfig_reset(cdev->gadget);
+	status = usb_add_function(&loopback_driver, func_lb);
+	if (status)
+		goto err_free_otg_desc;
+
+	usb_ep_autoconfig_reset(cdev->gadget);
+	usb_composite_overwrite_options(cdev, &coverwrite);
+
+	INFO(cdev, "%s, version: " DRIVER_VERSION "\n", longname);
+
+	return 0;
+
+err_free_otg_desc:
+	kfree(otg_desc[0]);
+	otg_desc[0] = NULL;
+err_conf_flb:
+	usb_put_function(func_lb);
+	func_lb = NULL;
+err_put_func_inst_lb:
+	usb_put_function_instance(func_inst_lb);
+	func_inst_lb = NULL;
+err_put_func_ss:
+	usb_put_function(func_ss);
+	func_ss = NULL;
+err_put_func_inst_ss:
+	usb_put_function_instance(func_inst_ss);
+	func_inst_ss = NULL;
+	return status;
+}
+
+static int zero_unbind(struct usb_composite_dev *cdev)
+{
+	del_timer_sync(&autoresume_timer);
+	if (!IS_ERR_OR_NULL(func_ss))
+		usb_put_function(func_ss);
+	usb_put_function_instance(func_inst_ss);
+	if (!IS_ERR_OR_NULL(func_lb))
+		usb_put_function(func_lb);
+	usb_put_function_instance(func_inst_lb);
+	kfree(otg_desc[0]);
+	otg_desc[0] = NULL;
+
+	return 0;
+}
+
+static struct usb_composite_driver zero_driver = {
+	.name		= "zero",
+	.dev		= &device_desc,
+	.strings	= dev_strings,
+	.max_speed	= USB_SPEED_SUPER,
+	.bind		= zero_bind,
+	.unbind		= zero_unbind,
+	.suspend	= zero_suspend,
+	.resume		= zero_resume,
+};
+
+module_usb_composite_driver(zero_driver);
+
+MODULE_AUTHOR("David Brownell");
+MODULE_LICENSE("GPL");