[deliverable/linux.git] / drivers / usb / gadget / f_loopback.c

/*
 * f_loopback.c - USB peripheral loopback configuration driver
 *
 * Copyright (C) 2003-2008 David Brownell
 * Copyright (C) 2008 by Nokia Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/* #define VERBOSE_DEBUG */

#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/device.h>

#include "g_zero.h"
#include "gadget_chips.h"


/*
 * LOOPBACK FUNCTION ... a testing vehicle for USB peripherals,
 *
 * This takes messages of various sizes written OUT to a device, and loops
 * them back so they can be read IN from it.  It has been used by certain
 * test applications.  It supports limited testing of data queueing logic.
 *
 *
 * This is currently packaged as a configuration driver, which can't be
 * combined with other functions to make composite devices.  However, it
 * can be combined with other independent configurations.
 */
struct f_loopback {
	struct usb_function	function;

	struct usb_ep		*in_ep;
	struct usb_ep		*out_ep;
};

static inline struct f_loopback *func_to_loop(struct usb_function *f)
{
	return container_of(f, struct f_loopback, function);
}

static unsigned qlen = 32;
module_param(qlen, uint, 0);
MODULE_PARM_DESC(qlenn, "depth of loopback queue");

/*-------------------------------------------------------------------------*/

static struct usb_interface_descriptor loopback_intf = {
	.bLength =		sizeof loopback_intf,
	.bDescriptorType =	USB_DT_INTERFACE,

	.bNumEndpoints =	2,
	.bInterfaceClass =	USB_CLASS_VENDOR_SPEC,
	/* .iInterface = DYNAMIC */
};

/* full speed support: */

static struct usb_endpoint_descriptor fs_loop_source_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	.bEndpointAddress =	USB_DIR_IN,
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
};

static struct usb_endpoint_descriptor fs_loop_sink_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	.bEndpointAddress =	USB_DIR_OUT,
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
};

static struct usb_descriptor_header *fs_loopback_descs[] = {
	(struct usb_descriptor_header *) &loopback_intf,
	(struct usb_descriptor_header *) &fs_loop_sink_desc,
	(struct usb_descriptor_header *) &fs_loop_source_desc,
	NULL,
};

/* high speed support: */

static struct usb_endpoint_descriptor hs_loop_source_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize =	cpu_to_le16(512),
};

static struct usb_endpoint_descriptor hs_loop_sink_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize =	cpu_to_le16(512),
};

static struct usb_descriptor_header *hs_loopback_descs[] = {
	(struct usb_descriptor_header *) &loopback_intf,
	(struct usb_descriptor_header *) &hs_loop_source_desc,
	(struct usb_descriptor_header *) &hs_loop_sink_desc,
	NULL,
};

/* function-specific strings: */

static struct usb_string strings_loopback[] = {
	[0].s = "loop input to output",
	{  }			/* end of list */
};

static struct usb_gadget_strings stringtab_loop = {
	.language	= 0x0409,	/* en-us */
	.strings	= strings_loopback,
};

static struct usb_gadget_strings *loopback_strings[] = {
	&stringtab_loop,
	NULL,
};

/*-------------------------------------------------------------------------*/

static int __init
loopback_bind(struct usb_configuration *c, struct usb_function *f)
{
	struct usb_composite_dev *cdev = c->cdev;
	struct f_loopback	*loop = func_to_loop(f);
	int			id;

	/* allocate interface ID(s) */
	id = usb_interface_id(c, f);
	if (id < 0)
		return id;
	loopback_intf.bInterfaceNumber = id;

	/* allocate endpoints */

	loop->in_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_source_desc);
	if (!loop->in_ep) {
autoconf_fail:
		ERROR(cdev, "%s: can't autoconfigure on %s\n",
			f->name, cdev->gadget->name);
		return -ENODEV;
	}
	loop->in_ep->driver_data = cdev;	/* claim */

	loop->out_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_sink_desc);
	if (!loop->out_ep)
		goto autoconf_fail;
	loop->out_ep->driver_data = cdev;	/* claim */

	/* support high speed hardware */
	if (gadget_is_dualspeed(c->cdev->gadget)) {
		hs_loop_source_desc.bEndpointAddress =
				fs_loop_source_desc.bEndpointAddress;
		hs_loop_sink_desc.bEndpointAddress =
				fs_loop_sink_desc.bEndpointAddress;
		f->hs_descriptors = hs_loopback_descs;
	}

	DBG(cdev, "%s speed %s: IN/%s, OUT/%s\n",
			gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
			f->name, loop->in_ep->name, loop->out_ep->name);
	return 0;
}

static void
loopback_unbind(struct usb_configuration *c, struct usb_function *f)
{
	kfree(func_to_loop(f));
}

static void loopback_complete(struct usb_ep *ep, struct usb_request *req)
{
	struct f_loopback	*loop = ep->driver_data;
	struct usb_composite_dev *cdev = loop->function.config->cdev;
	int			status = req->status;

	switch (status) {

	case 0:				/* normal completion? */
		if (ep == loop->out_ep) {
			/* loop this OUT packet back IN to the host */
			req->zero = (req->actual < req->length);
			req->length = req->actual;
			status = usb_ep_queue(loop->in_ep, req, GFP_ATOMIC);
			if (status == 0)
				return;

			/* "should never get here" */
			ERROR(cdev, "can't loop %s to %s: %d\n",
				ep->name, loop->in_ep->name,
				status);
		}

		/* queue the buffer for some later OUT packet */
		req->length = buflen;
		status = usb_ep_queue(loop->out_ep, req, GFP_ATOMIC);
		if (status == 0)
			return;

		/* "should never get here" */
		/* FALLTHROUGH */

	default:
		ERROR(cdev, "%s loop complete --> %d, %d/%d\n", ep->name,
				status, req->actual, req->length);
		/* FALLTHROUGH */

	/* NOTE:  since this driver doesn't maintain an explicit record
	 * of requests it submitted (just maintains qlen count), we
	 * rely on the hardware driver to clean up on disconnect or
	 * endpoint disable.
	 */
	case -ECONNABORTED:		/* hardware forced ep reset */
	case -ECONNRESET:		/* request dequeued */
	case -ESHUTDOWN:		/* disconnect from host */
		free_ep_req(ep, req);
		return;
	}
}

static void disable_loopback(struct f_loopback *loop)
{
	struct usb_composite_dev	*cdev;

	cdev = loop->function.config->cdev;
	disable_endpoints(cdev, loop->in_ep, loop->out_ep);
	VDBG(cdev, "%s disabled\n", loop->function.name);
}

static int
enable_loopback(struct usb_composite_dev *cdev, struct f_loopback *loop)
{
	int					result = 0;
	struct usb_ep				*ep;
	struct usb_request			*req;
	unsigned				i;

	/* one endpoint writes data back IN to the host */
	ep = loop->in_ep;
	ep->desc = ep_choose(cdev->gadget,
			&hs_loop_source_desc, &fs_loop_source_desc);
	result = usb_ep_enable(ep);
	if (result < 0)
		return result;
	ep->driver_data = loop;

	/* one endpoint just reads OUT packets */
	ep = loop->out_ep;
	ep->desc = ep_choose(cdev->gadget,
			&hs_loop_sink_desc, &fs_loop_sink_desc);
	result = usb_ep_enable(ep);
	if (result < 0) {
fail0:
		ep = loop->in_ep;
		usb_ep_disable(ep);
		ep->driver_data = NULL;
		return result;
	}
	ep->driver_data = loop;

	/* allocate a bunch of read buffers and queue them all at once.
	 * we buffer at most 'qlen' transfers; fewer if any need more
	 * than 'buflen' bytes each.
	 */
	for (i = 0; i < qlen && result == 0; i++) {
		req = alloc_ep_req(ep);
		if (req) {
			req->complete = loopback_complete;
			result = usb_ep_queue(ep, req, GFP_ATOMIC);
			if (result)
				ERROR(cdev, "%s queue req --> %d\n",
						ep->name, result);
		} else {
			usb_ep_disable(ep);
			ep->driver_data = NULL;
			result = -ENOMEM;
			goto fail0;
		}
	}

	DBG(cdev, "%s enabled\n", loop->function.name);
	return result;
}

static int loopback_set_alt(struct usb_function *f,
		unsigned intf, unsigned alt)
{
	struct f_loopback	*loop = func_to_loop(f);
	struct usb_composite_dev *cdev = f->config->cdev;

	/* we know alt is zero */
	if (loop->in_ep->driver_data)
		disable_loopback(loop);
	return enable_loopback(cdev, loop);
}

static void loopback_disable(struct usb_function *f)
{
	struct f_loopback	*loop = func_to_loop(f);

	disable_loopback(loop);
}

/*-------------------------------------------------------------------------*/

static int __init loopback_bind_config(struct usb_configuration *c)
{
	struct f_loopback	*loop;
	int			status;

	loop = kzalloc(sizeof *loop, GFP_KERNEL);
	if (!loop)
		return -ENOMEM;

	loop->function.name = "loopback";
	loop->function.descriptors = fs_loopback_descs;
	loop->function.bind = loopback_bind;
	loop->function.unbind = loopback_unbind;
	loop->function.set_alt = loopback_set_alt;
	loop->function.disable = loopback_disable;

	status = usb_add_function(c, &loop->function);
	if (status)
		kfree(loop);
	return status;
}

static struct usb_configuration loopback_driver = {
	.label		= "loopback",
	.strings	= loopback_strings,
	.bConfigurationValue = 2,
	.bmAttributes	= USB_CONFIG_ATT_SELFPOWER,
	/* .iConfiguration = DYNAMIC */
};

/**
 * loopback_add - add a loopback testing configuration to a device
 * @cdev: the device to support the loopback configuration
 */
int __init loopback_add(struct usb_composite_dev *cdev, bool autoresume)
{
	int id;

	/* allocate string ID(s) */
	id = usb_string_id(cdev);
	if (id < 0)
		return id;
	strings_loopback[0].id = id;

	loopback_intf.iInterface = id;
	loopback_driver.iConfiguration = id;

	/* support autoresume for remote wakeup testing */
	if (autoresume)
		sourcesink_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;

	/* support OTG systems */
	if (gadget_is_otg(cdev->gadget)) {
		loopback_driver.descriptors = otg_desc;
		loopback_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
	}

	return usb_add_config(cdev, &loopback_driver, loopback_bind_config);
}
Commit	Line	Data
e5760fda DB	1	/*
	2	* f_loopback.c - USB peripheral loopback configuration driver
	3	*
	4	* Copyright (C) 2003-2008 David Brownell
	5	* Copyright (C) 2008 by Nokia Corporation
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License as published by
	9	* the Free Software Foundation; either version 2 of the License, or
	10	* (at your option) any later version.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program; if not, write to the Free Software
	19	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	20	*/
	21
	22	/* #define VERBOSE_DEBUG */
	23
5a0e3ad6	24	#include <linux/slab.h>
e5760fda	25	#include <linux/kernel.h>
e5760fda DB	26	#include <linux/device.h>
	27
	28	#include "g_zero.h"
	29	#include "gadget_chips.h"
	30
	31
	32	/*
	33	* LOOPBACK FUNCTION ... a testing vehicle for USB peripherals,
	34	*
	35	* This takes messages of various sizes written OUT to a device, and loops
	36	* them back so they can be read IN from it. It has been used by certain
	37	* test applications. It supports limited testing of data queueing logic.
	38	*
	39	*
	40	* This is currently packaged as a configuration driver, which can't be
	41	* combined with other functions to make composite devices. However, it
	42	* can be combined with other independent configurations.
	43	*/
	44	struct f_loopback {
	45	struct usb_function function;
	46
	47	struct usb_ep *in_ep;
	48	struct usb_ep *out_ep;
	49	};
	50
	51	static inline struct f_loopback func_to_loop(struct usb_function f)
	52	{
	53	return container_of(f, struct f_loopback, function);
	54	}
	55
	56	static unsigned qlen = 32;
	57	module_param(qlen, uint, 0);
	58	MODULE_PARM_DESC(qlenn, "depth of loopback queue");
	59
	60	/-------------------------------------------------------------------------/
	61
	62	static struct usb_interface_descriptor loopback_intf = {
	63	.bLength = sizeof loopback_intf,
	64	.bDescriptorType = USB_DT_INTERFACE,
	65
	66	.bNumEndpoints = 2,
	67	.bInterfaceClass = USB_CLASS_VENDOR_SPEC,
	68	/* .iInterface = DYNAMIC */
	69	};
	70
	71	/* full speed support: */
	72
7e75bc0f	73	static struct usb_endpoint_descriptor fs_loop_source_desc = {
e5760fda DB	74	.bLength = USB_DT_ENDPOINT_SIZE,
	75	.bDescriptorType = USB_DT_ENDPOINT,
	76
	77	.bEndpointAddress = USB_DIR_IN,
	78	.bmAttributes = USB_ENDPOINT_XFER_BULK,
	79	};
	80
7e75bc0f	81	static struct usb_endpoint_descriptor fs_loop_sink_desc = {
e5760fda DB	82	.bLength = USB_DT_ENDPOINT_SIZE,
	83	.bDescriptorType = USB_DT_ENDPOINT,
	84
	85	.bEndpointAddress = USB_DIR_OUT,
	86	.bmAttributes = USB_ENDPOINT_XFER_BULK,
	87	};
	88
	89	static struct usb_descriptor_header *fs_loopback_descs[] = {
	90	(struct usb_descriptor_header *) &loopback_intf,
7e75bc0f DB	91	(struct usb_descriptor_header *) &fs_loop_sink_desc,
7e75bc0f DB	92	(struct usb_descriptor_header *) &fs_loop_source_desc,
e5760fda DB	93	NULL,
	94	};
	95
	96	/* high speed support: */
	97
7e75bc0f	98	static struct usb_endpoint_descriptor hs_loop_source_desc = {
e5760fda DB	99	.bLength = USB_DT_ENDPOINT_SIZE,
	100	.bDescriptorType = USB_DT_ENDPOINT,
	101
	102	.bmAttributes = USB_ENDPOINT_XFER_BULK,
551509d2	103	.wMaxPacketSize = cpu_to_le16(512),
e5760fda DB	104	};
e5760fda DB	105
7e75bc0f	106	static struct usb_endpoint_descriptor hs_loop_sink_desc = {
e5760fda DB	107	.bLength = USB_DT_ENDPOINT_SIZE,
	108	.bDescriptorType = USB_DT_ENDPOINT,
	109
	110	.bmAttributes = USB_ENDPOINT_XFER_BULK,
551509d2	111	.wMaxPacketSize = cpu_to_le16(512),
e5760fda DB	112	};
	113
	114	static struct usb_descriptor_header *hs_loopback_descs[] = {
	115	(struct usb_descriptor_header *) &loopback_intf,
7e75bc0f DB	116	(struct usb_descriptor_header *) &hs_loop_source_desc,
7e75bc0f DB	117	(struct usb_descriptor_header *) &hs_loop_sink_desc,
e5760fda DB	118	NULL,
	119	};
	120
	121	/* function-specific strings: */
	122
	123	static struct usb_string strings_loopback[] = {
	124	[0].s = "loop input to output",
	125	{ } /* end of list */
	126	};
	127
	128	static struct usb_gadget_strings stringtab_loop = {
	129	.language = 0x0409, /* en-us */
	130	.strings = strings_loopback,
	131	};
	132
	133	static struct usb_gadget_strings *loopback_strings[] = {
	134	&stringtab_loop,
	135	NULL,
	136	};
	137
	138	/-------------------------------------------------------------------------/
	139
	140	static int __init
	141	loopback_bind(struct usb_configuration c, struct usb_function f)
	142	{
	143	struct usb_composite_dev *cdev = c->cdev;
	144	struct f_loopback *loop = func_to_loop(f);
	145	int id;
	146
	147	/* allocate interface ID(s) */
	148	id = usb_interface_id(c, f);
	149	if (id < 0)
	150	return id;
	151	loopback_intf.bInterfaceNumber = id;
	152
	153	/* allocate endpoints */
	154
7e75bc0f	155	loop->in_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_source_desc);
e5760fda DB	156	if (!loop->in_ep) {
	157	autoconf_fail:
	158	ERROR(cdev, "%s: can't autoconfigure on %s\n",
	159	f->name, cdev->gadget->name);
	160	return -ENODEV;
	161	}
	162	loop->in_ep->driver_data = cdev; /* claim */
	163
7e75bc0f	164	loop->out_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_sink_desc);
e5760fda DB	165	if (!loop->out_ep)
	166	goto autoconf_fail;
	167	loop->out_ep->driver_data = cdev; /* claim */
	168
	169	/* support high speed hardware */
	170	if (gadget_is_dualspeed(c->cdev->gadget)) {
7e75bc0f DB	171	hs_loop_source_desc.bEndpointAddress =
	172	fs_loop_source_desc.bEndpointAddress;
	173	hs_loop_sink_desc.bEndpointAddress =
	174	fs_loop_sink_desc.bEndpointAddress;
e5760fda DB	175	f->hs_descriptors = hs_loopback_descs;
	176	}
	177
	178	DBG(cdev, "%s speed %s: IN/%s, OUT/%s\n",
	179	gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
	180	f->name, loop->in_ep->name, loop->out_ep->name);
	181	return 0;
	182	}
	183
	184	static void
	185	loopback_unbind(struct usb_configuration c, struct usb_function f)
	186	{
	187	kfree(func_to_loop(f));
	188	}
	189
	190	static void loopback_complete(struct usb_ep ep, struct usb_request req)
	191	{
	192	struct f_loopback *loop = ep->driver_data;
	193	struct usb_composite_dev *cdev = loop->function.config->cdev;
	194	int status = req->status;
	195
	196	switch (status) {
	197
	198	case 0: /* normal completion? */
	199	if (ep == loop->out_ep) {
	200	/* loop this OUT packet back IN to the host */
	201	req->zero = (req->actual < req->length);
	202	req->length = req->actual;
	203	status = usb_ep_queue(loop->in_ep, req, GFP_ATOMIC);
	204	if (status == 0)
	205	return;
	206
	207	/* "should never get here" */
	208	ERROR(cdev, "can't loop %s to %s: %d\n",
	209	ep->name, loop->in_ep->name,
	210	status);
	211	}
	212
	213	/* queue the buffer for some later OUT packet */
	214	req->length = buflen;
	215	status = usb_ep_queue(loop->out_ep, req, GFP_ATOMIC);
	216	if (status == 0)
	217	return;
	218
	219	/* "should never get here" */
	220	/* FALLTHROUGH */
	221
	222	default:
	223	ERROR(cdev, "%s loop complete --> %d, %d/%d\n", ep->name,
	224	status, req->actual, req->length);
	225	/* FALLTHROUGH */
	226
	227	/* NOTE: since this driver doesn't maintain an explicit record
	228	* of requests it submitted (just maintains qlen count), we
	229	* rely on the hardware driver to clean up on disconnect or
	230	* endpoint disable.
	231	*/
	232	case -ECONNABORTED: /* hardware forced ep reset */
	233	case -ECONNRESET: /* request dequeued */
	234	case -ESHUTDOWN: /* disconnect from host */
	235	free_ep_req(ep, req);
	236	return;
	237	}
	238	}
239
240	static void disable_loopback(struct f_loopback *loop)
241	{
242	struct usb_composite_dev *cdev;
243
244	cdev = loop->function.config->cdev;
245	disable_endpoints(cdev, loop->in_ep, loop->out_ep);
246	VDBG(cdev, "%s disabled\n", loop->function.name);
247	}
248
249	static int
250	enable_loopback(struct usb_composite_dev cdev, struct f_loopback loop)
251	{
252	int result = 0;
e5760fda DB	253	struct usb_ep *ep;
	254	struct usb_request *req;
	255	unsigned i;
	256
e5760fda DB	257	/* one endpoint writes data back IN to the host */
e5760fda DB	258	ep = loop->in_ep;
72c973dd TB	259	ep->desc = ep_choose(cdev->gadget,
	260	&hs_loop_source_desc, &fs_loop_source_desc);
	261	result = usb_ep_enable(ep);
e5760fda DB	262	if (result < 0)
	263	return result;
	264	ep->driver_data = loop;
	265
	266	/* one endpoint just reads OUT packets */
	267	ep = loop->out_ep;
72c973dd TB	268	ep->desc = ep_choose(cdev->gadget,
	269	&hs_loop_sink_desc, &fs_loop_sink_desc);
	270	result = usb_ep_enable(ep);
e5760fda DB	271	if (result < 0) {
	272	fail0:
	273	ep = loop->in_ep;
	274	usb_ep_disable(ep);
	275	ep->driver_data = NULL;
	276	return result;
	277	}
	278	ep->driver_data = loop;
	279
	280	/* allocate a bunch of read buffers and queue them all at once.
	281	* we buffer at most 'qlen' transfers; fewer if any need more
	282	* than 'buflen' bytes each.
	283	*/
	284	for (i = 0; i < qlen && result == 0; i++) {
	285	req = alloc_ep_req(ep);
	286	if (req) {
	287	req->complete = loopback_complete;
	288	result = usb_ep_queue(ep, req, GFP_ATOMIC);
	289	if (result)
	290	ERROR(cdev, "%s queue req --> %d\n",
	291	ep->name, result);
	292	} else {
	293	usb_ep_disable(ep);
	294	ep->driver_data = NULL;
	295	result = -ENOMEM;
	296	goto fail0;
	297	}
	298	}
	299
	300	DBG(cdev, "%s enabled\n", loop->function.name);
	301	return result;
	302	}
	303
	304	static int loopback_set_alt(struct usb_function *f,
	305	unsigned intf, unsigned alt)
	306	{
	307	struct f_loopback *loop = func_to_loop(f);
	308	struct usb_composite_dev *cdev = f->config->cdev;
	309
	310	/* we know alt is zero */
	311	if (loop->in_ep->driver_data)
	312	disable_loopback(loop);
	313	return enable_loopback(cdev, loop);
	314	}
	315
	316	static void loopback_disable(struct usb_function *f)
	317	{
	318	struct f_loopback *loop = func_to_loop(f);
	319
	320	disable_loopback(loop);
	321	}
	322
	323	/-------------------------------------------------------------------------/
	324
e12995ec	325	static int __init loopback_bind_config(struct usb_configuration *c)
e5760fda DB	326	{
	327	struct f_loopback *loop;
	328	int status;
	329
	330	loop = kzalloc(sizeof *loop, GFP_KERNEL);
	331	if (!loop)
	332	return -ENOMEM;
	333
	334	loop->function.name = "loopback";
	335	loop->function.descriptors = fs_loopback_descs;
	336	loop->function.bind = loopback_bind;
	337	loop->function.unbind = loopback_unbind;
	338	loop->function.set_alt = loopback_set_alt;
	339	loop->function.disable = loopback_disable;
	340
	341	status = usb_add_function(c, &loop->function);
	342	if (status)
	343	kfree(loop);
	344	return status;
	345	}
	346
e12995ec	347	static struct usb_configuration loopback_driver = {
e5760fda DB	348	.label = "loopback",
e5760fda DB	349	.strings = loopback_strings,
e5760fda DB	350	.bConfigurationValue = 2,
e5760fda DB	351	.bmAttributes = USB_CONFIG_ATT_SELFPOWER,
e5760fda DB	352	/* .iConfiguration = DYNAMIC */
	353	};
	354
	355	/**
	356	* loopback_add - add a loopback testing configuration to a device
	357	* @cdev: the device to support the loopback configuration
	358	*/
ab943a2e	359	int __init loopback_add(struct usb_composite_dev *cdev, bool autoresume)
e5760fda DB	360	{
	361	int id;
	362
	363	/* allocate string ID(s) */
	364	id = usb_string_id(cdev);
	365	if (id < 0)
	366	return id;
	367	strings_loopback[0].id = id;
	368
	369	loopback_intf.iInterface = id;
	370	loopback_driver.iConfiguration = id;
	371
ab943a2e DB	372	/* support autoresume for remote wakeup testing */
	373	if (autoresume)
	374	sourcesink_driver.bmAttributes \|= USB_CONFIG_ATT_WAKEUP;
	375
e5760fda DB	376	/* support OTG systems */
	377	if (gadget_is_otg(cdev->gadget)) {
	378	loopback_driver.descriptors = otg_desc;
	379	loopback_driver.bmAttributes \|= USB_CONFIG_ATT_WAKEUP;
	380	}
	381
c9bfff9c	382	return usb_add_config(cdev, &loopback_driver, loopback_bind_config);
e5760fda	383	}