[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.
 */

/* #define VERBOSE_DEBUG */

#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/usb/composite.h>

#include "g_zero.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;
static unsigned buflen;

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

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,
};

/* super speed support: */

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

	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize =	cpu_to_le16(1024),
};

struct usb_ss_ep_comp_descriptor ss_loop_source_comp_desc = {
	.bLength =		USB_DT_SS_EP_COMP_SIZE,
	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
	.bMaxBurst =		0,
	.bmAttributes =		0,
	.wBytesPerInterval =	0,
};

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

	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize =	cpu_to_le16(1024),
};

struct usb_ss_ep_comp_descriptor ss_loop_sink_comp_desc = {
	.bLength =		USB_DT_SS_EP_COMP_SIZE,
	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
	.bMaxBurst =		0,
	.bmAttributes =		0,
	.wBytesPerInterval =	0,
};

static struct usb_descriptor_header *ss_loopback_descs[] = {
	(struct usb_descriptor_header *) &loopback_intf,
	(struct usb_descriptor_header *) &ss_loop_source_desc,
	(struct usb_descriptor_header *) &ss_loop_source_comp_desc,
	(struct usb_descriptor_header *) &ss_loop_sink_desc,
	(struct usb_descriptor_header *) &ss_loop_sink_comp_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 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;
	int ret;

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

	id = usb_string_id(cdev);
	if (id < 0)
		return id;
	strings_loopback[0].id = id;
	loopback_intf.iInterface = 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 */
	hs_loop_source_desc.bEndpointAddress =
		fs_loop_source_desc.bEndpointAddress;
	hs_loop_sink_desc.bEndpointAddress = fs_loop_sink_desc.bEndpointAddress;

	/* support super speed hardware */
	ss_loop_source_desc.bEndpointAddress =
		fs_loop_source_desc.bEndpointAddress;
	ss_loop_sink_desc.bEndpointAddress = fs_loop_sink_desc.bEndpointAddress;

	ret = usb_assign_descriptors(f, fs_loopback_descs, hs_loopback_descs,
			ss_loopback_descs);
	if (ret)
		return ret;

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

static void lb_free_func(struct usb_function *f)
{
	usb_free_all_descriptors(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, NULL, NULL);
	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;
	result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
	if (result)
		return result;
	result = usb_ep_enable(ep);
	if (result < 0)
		return result;
	ep->driver_data = loop;

	/* one endpoint just reads OUT packets */
	ep = loop->out_ep;
	result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
	if (result)
		goto fail0;

	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, 0);
		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 struct usb_function *loopback_alloc(struct usb_function_instance *fi)
{
	struct f_loopback	*loop;
	struct f_lb_opts	*lb_opts;

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

	lb_opts = container_of(fi, struct f_lb_opts, func_inst);
	buflen = lb_opts->bulk_buflen;
	qlen = lb_opts->qlen;
	if (!qlen)
		qlen = 32;

	loop->function.name = "loopback";
	loop->function.bind = loopback_bind;
	loop->function.set_alt = loopback_set_alt;
	loop->function.disable = loopback_disable;
	loop->function.strings = loopback_strings;

	loop->function.free_func = lb_free_func;

	return &loop->function;
}

static void lb_free_instance(struct usb_function_instance *fi)
{
	struct f_lb_opts *lb_opts;

	lb_opts = container_of(fi, struct f_lb_opts, func_inst);
	kfree(lb_opts);
}

static struct usb_function_instance *loopback_alloc_instance(void)
{
	struct f_lb_opts *lb_opts;

	lb_opts = kzalloc(sizeof(*lb_opts), GFP_KERNEL);
	if (!lb_opts)
		return ERR_PTR(-ENOMEM);
	lb_opts->func_inst.free_func_inst = lb_free_instance;
	return  &lb_opts->func_inst;
}
DECLARE_USB_FUNCTION(Loopback, loopback_alloc_instance, loopback_alloc);

int __init lb_modinit(void)
{
	int ret;

	ret = usb_function_register(&Loopbackusb_func);
	if (ret)
		return ret;
	return ret;
}
void __exit lb_modexit(void)
{
	usb_function_unregister(&Loopbackusb_func);
}

MODULE_LICENSE("GPL");
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.
e5760fda DB	11	*/
	12
	13	/* #define VERBOSE_DEBUG */
	14
5a0e3ad6	15	#include <linux/slab.h>
e5760fda	16	#include <linux/kernel.h>
e5760fda	17	#include <linux/device.h>
cf9a08ae SAS	18	#include <linux/module.h>
	19	#include <linux/err.h>
	20	#include <linux/usb/composite.h>
e5760fda DB	21
e5760fda DB	22	#include "g_zero.h"
e5760fda DB	23
	24	/*
	25	* LOOPBACK FUNCTION ... a testing vehicle for USB peripherals,
	26	*
	27	* This takes messages of various sizes written OUT to a device, and loops
	28	* them back so they can be read IN from it. It has been used by certain
	29	* test applications. It supports limited testing of data queueing logic.
	30	*
	31	*
	32	* This is currently packaged as a configuration driver, which can't be
	33	* combined with other functions to make composite devices. However, it
	34	* can be combined with other independent configurations.
	35	*/
	36	struct f_loopback {
	37	struct usb_function function;
	38
	39	struct usb_ep *in_ep;
	40	struct usb_ep *out_ep;
	41	};
	42
	43	static inline struct f_loopback func_to_loop(struct usb_function f)
	44	{
	45	return container_of(f, struct f_loopback, function);
	46	}
	47
cf9a08ae SAS	48	static unsigned qlen;
cf9a08ae SAS	49	static unsigned buflen;
e5760fda DB	50
	51	/-------------------------------------------------------------------------/
	52
	53	static struct usb_interface_descriptor loopback_intf = {
	54	.bLength = sizeof loopback_intf,
	55	.bDescriptorType = USB_DT_INTERFACE,
	56
	57	.bNumEndpoints = 2,
	58	.bInterfaceClass = USB_CLASS_VENDOR_SPEC,
	59	/* .iInterface = DYNAMIC */
	60	};
	61
	62	/* full speed support: */
	63
7e75bc0f	64	static struct usb_endpoint_descriptor fs_loop_source_desc = {
e5760fda DB	65	.bLength = USB_DT_ENDPOINT_SIZE,
	66	.bDescriptorType = USB_DT_ENDPOINT,
	67
	68	.bEndpointAddress = USB_DIR_IN,
	69	.bmAttributes = USB_ENDPOINT_XFER_BULK,
	70	};
	71
7e75bc0f	72	static struct usb_endpoint_descriptor fs_loop_sink_desc = {
e5760fda DB	73	.bLength = USB_DT_ENDPOINT_SIZE,
	74	.bDescriptorType = USB_DT_ENDPOINT,
	75
	76	.bEndpointAddress = USB_DIR_OUT,
	77	.bmAttributes = USB_ENDPOINT_XFER_BULK,
	78	};
	79
	80	static struct usb_descriptor_header *fs_loopback_descs[] = {
	81	(struct usb_descriptor_header *) &loopback_intf,
7e75bc0f DB	82	(struct usb_descriptor_header *) &fs_loop_sink_desc,
7e75bc0f DB	83	(struct usb_descriptor_header *) &fs_loop_source_desc,
e5760fda DB	84	NULL,
	85	};
	86
	87	/* high speed support: */
	88
7e75bc0f	89	static struct usb_endpoint_descriptor hs_loop_source_desc = {
e5760fda DB	90	.bLength = USB_DT_ENDPOINT_SIZE,
	91	.bDescriptorType = USB_DT_ENDPOINT,
	92
	93	.bmAttributes = USB_ENDPOINT_XFER_BULK,
551509d2	94	.wMaxPacketSize = cpu_to_le16(512),
e5760fda DB	95	};
e5760fda DB	96
7e75bc0f	97	static struct usb_endpoint_descriptor hs_loop_sink_desc = {
e5760fda DB	98	.bLength = USB_DT_ENDPOINT_SIZE,
	99	.bDescriptorType = USB_DT_ENDPOINT,
	100
	101	.bmAttributes = USB_ENDPOINT_XFER_BULK,
551509d2	102	.wMaxPacketSize = cpu_to_le16(512),
e5760fda DB	103	};
	104
	105	static struct usb_descriptor_header *hs_loopback_descs[] = {
	106	(struct usb_descriptor_header *) &loopback_intf,
7e75bc0f DB	107	(struct usb_descriptor_header *) &hs_loop_source_desc,
7e75bc0f DB	108	(struct usb_descriptor_header *) &hs_loop_sink_desc,
e5760fda DB	109	NULL,
	110	};
	111
57c97c02 AB	112	/* super speed support: */
	113
	114	static struct usb_endpoint_descriptor ss_loop_source_desc = {
	115	.bLength = USB_DT_ENDPOINT_SIZE,
	116	.bDescriptorType = USB_DT_ENDPOINT,
	117
	118	.bmAttributes = USB_ENDPOINT_XFER_BULK,
	119	.wMaxPacketSize = cpu_to_le16(1024),
	120	};
	121
	122	struct usb_ss_ep_comp_descriptor ss_loop_source_comp_desc = {
	123	.bLength = USB_DT_SS_EP_COMP_SIZE,
	124	.bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
	125	.bMaxBurst = 0,
	126	.bmAttributes = 0,
	127	.wBytesPerInterval = 0,
	128	};
	129
	130	static struct usb_endpoint_descriptor ss_loop_sink_desc = {
	131	.bLength = USB_DT_ENDPOINT_SIZE,
	132	.bDescriptorType = USB_DT_ENDPOINT,
	133
	134	.bmAttributes = USB_ENDPOINT_XFER_BULK,
	135	.wMaxPacketSize = cpu_to_le16(1024),
	136	};
	137
	138	struct usb_ss_ep_comp_descriptor ss_loop_sink_comp_desc = {
	139	.bLength = USB_DT_SS_EP_COMP_SIZE,
	140	.bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
	141	.bMaxBurst = 0,
	142	.bmAttributes = 0,
	143	.wBytesPerInterval = 0,
	144	};
	145
	146	static struct usb_descriptor_header *ss_loopback_descs[] = {
	147	(struct usb_descriptor_header *) &loopback_intf,
	148	(struct usb_descriptor_header *) &ss_loop_source_desc,
	149	(struct usb_descriptor_header *) &ss_loop_source_comp_desc,
	150	(struct usb_descriptor_header *) &ss_loop_sink_desc,
	151	(struct usb_descriptor_header *) &ss_loop_sink_comp_desc,
	152	NULL,
	153	};
	154
e5760fda DB	155	/* function-specific strings: */
	156
	157	static struct usb_string strings_loopback[] = {
	158	[0].s = "loop input to output",
	159	{ } /* end of list */
	160	};
	161
	162	static struct usb_gadget_strings stringtab_loop = {
	163	.language = 0x0409, /* en-us */
	164	.strings = strings_loopback,
	165	};
	166
	167	static struct usb_gadget_strings *loopback_strings[] = {
	168	&stringtab_loop,
	169	NULL,
	170	};
	171
	172	/-------------------------------------------------------------------------/
	173
cf9a08ae	174	static int loopback_bind(struct usb_configuration c, struct usb_function f)
e5760fda DB	175	{
	176	struct usb_composite_dev *cdev = c->cdev;
	177	struct f_loopback *loop = func_to_loop(f);
	178	int id;
10287bae	179	int ret;
e5760fda DB	180
	181	/* allocate interface ID(s) */
	182	id = usb_interface_id(c, f);
	183	if (id < 0)
	184	return id;
	185	loopback_intf.bInterfaceNumber = id;
	186
78f46f09 SAS	187	id = usb_string_id(cdev);
	188	if (id < 0)
	189	return id;
	190	strings_loopback[0].id = id;
	191	loopback_intf.iInterface = id;
	192
e5760fda DB	193	/* allocate endpoints */
e5760fda DB	194
7e75bc0f	195	loop->in_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_source_desc);
e5760fda DB	196	if (!loop->in_ep) {
	197	autoconf_fail:
	198	ERROR(cdev, "%s: can't autoconfigure on %s\n",
	199	f->name, cdev->gadget->name);
	200	return -ENODEV;
	201	}
	202	loop->in_ep->driver_data = cdev; /* claim */
	203
7e75bc0f	204	loop->out_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_sink_desc);
e5760fda DB	205	if (!loop->out_ep)
	206	goto autoconf_fail;
	207	loop->out_ep->driver_data = cdev; /* claim */
	208
	209	/* support high speed hardware */
10287bae SAS	210	hs_loop_source_desc.bEndpointAddress =
	211	fs_loop_source_desc.bEndpointAddress;
	212	hs_loop_sink_desc.bEndpointAddress = fs_loop_sink_desc.bEndpointAddress;
e5760fda	213
57c97c02	214	/* support super speed hardware */
10287bae SAS	215	ss_loop_source_desc.bEndpointAddress =
	216	fs_loop_source_desc.bEndpointAddress;
	217	ss_loop_sink_desc.bEndpointAddress = fs_loop_sink_desc.bEndpointAddress;
	218
	219	ret = usb_assign_descriptors(f, fs_loopback_descs, hs_loopback_descs,
	220	ss_loopback_descs);
	221	if (ret)
	222	return ret;
57c97c02	223
e5760fda	224	DBG(cdev, "%s speed %s: IN/%s, OUT/%s\n",
57c97c02 AB	225	(gadget_is_superspeed(c->cdev->gadget) ? "super" :
57c97c02 AB	226	(gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full")),
e5760fda DB	227	f->name, loop->in_ep->name, loop->out_ep->name);
	228	return 0;
	229	}
	230
cf9a08ae	231	static void lb_free_func(struct usb_function *f)
e5760fda	232	{
10287bae	233	usb_free_all_descriptors(f);
e5760fda DB	234	kfree(func_to_loop(f));
	235	}
	236
	237	static void loopback_complete(struct usb_ep ep, struct usb_request req)
	238	{
	239	struct f_loopback *loop = ep->driver_data;
	240	struct usb_composite_dev *cdev = loop->function.config->cdev;
	241	int status = req->status;
	242
	243	switch (status) {
	244
	245	case 0: /* normal completion? */
	246	if (ep == loop->out_ep) {
	247	/* loop this OUT packet back IN to the host */
	248	req->zero = (req->actual < req->length);
	249	req->length = req->actual;
	250	status = usb_ep_queue(loop->in_ep, req, GFP_ATOMIC);
	251	if (status == 0)
	252	return;
	253
	254	/* "should never get here" */
	255	ERROR(cdev, "can't loop %s to %s: %d\n",
	256	ep->name, loop->in_ep->name,
	257	status);
	258	}
	259
	260	/* queue the buffer for some later OUT packet */
	261	req->length = buflen;
	262	status = usb_ep_queue(loop->out_ep, req, GFP_ATOMIC);
	263	if (status == 0)
	264	return;
	265
	266	/* "should never get here" */
	267	/* FALLTHROUGH */
	268
	269	default:
	270	ERROR(cdev, "%s loop complete --> %d, %d/%d\n", ep->name,
	271	status, req->actual, req->length);
	272	/* FALLTHROUGH */
	273
	274	/* NOTE: since this driver doesn't maintain an explicit record
	275	* of requests it submitted (just maintains qlen count), we
	276	* rely on the hardware driver to clean up on disconnect or
	277	* endpoint disable.
	278	*/
	279	case -ECONNABORTED: /* hardware forced ep reset */
	280	case -ECONNRESET: /* request dequeued */
	281	case -ESHUTDOWN: /* disconnect from host */
	282	free_ep_req(ep, req);
	283	return;
	284	}
	285	}
	286
	287	static void disable_loopback(struct f_loopback *loop)
	288	{
	289	struct usb_composite_dev *cdev;
	290
	291	cdev = loop->function.config->cdev;
b4036ccd	292	disable_endpoints(cdev, loop->in_ep, loop->out_ep, NULL, NULL);
e5760fda DB	293	VDBG(cdev, "%s disabled\n", loop->function.name);
	294	}
	295
	296	static int
	297	enable_loopback(struct usb_composite_dev cdev, struct f_loopback loop)
	298	{
	299	int result = 0;
e5760fda DB	300	struct usb_ep *ep;
	301	struct usb_request *req;
	302	unsigned i;
	303
e5760fda DB	304	/* one endpoint writes data back IN to the host */
e5760fda DB	305	ep = loop->in_ep;
ea2a1df7 TB	306	result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
	307	if (result)
	308	return result;
72c973dd	309	result = usb_ep_enable(ep);
e5760fda DB	310	if (result < 0)
	311	return result;
	312	ep->driver_data = loop;
	313
	314	/* one endpoint just reads OUT packets */
	315	ep = loop->out_ep;
ea2a1df7 TB	316	result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
	317	if (result)
	318	goto fail0;
	319
72c973dd	320	result = usb_ep_enable(ep);
e5760fda DB	321	if (result < 0) {
	322	fail0:
	323	ep = loop->in_ep;
	324	usb_ep_disable(ep);
	325	ep->driver_data = NULL;
	326	return result;
	327	}
	328	ep->driver_data = loop;
	329
	330	/* allocate a bunch of read buffers and queue them all at once.
	331	* we buffer at most 'qlen' transfers; fewer if any need more
	332	* than 'buflen' bytes each.
	333	*/
	334	for (i = 0; i < qlen && result == 0; i++) {
b4036ccd	335	req = alloc_ep_req(ep, 0);
e5760fda DB	336	if (req) {
	337	req->complete = loopback_complete;
	338	result = usb_ep_queue(ep, req, GFP_ATOMIC);
	339	if (result)
	340	ERROR(cdev, "%s queue req --> %d\n",
	341	ep->name, result);
	342	} else {
	343	usb_ep_disable(ep);
	344	ep->driver_data = NULL;
	345	result = -ENOMEM;
	346	goto fail0;
	347	}
	348	}
	349
	350	DBG(cdev, "%s enabled\n", loop->function.name);
	351	return result;
	352	}
	353
	354	static int loopback_set_alt(struct usb_function *f,
	355	unsigned intf, unsigned alt)
	356	{
	357	struct f_loopback *loop = func_to_loop(f);
	358	struct usb_composite_dev *cdev = f->config->cdev;
	359
	360	/* we know alt is zero */
	361	if (loop->in_ep->driver_data)
	362	disable_loopback(loop);
	363	return enable_loopback(cdev, loop);
	364	}
	365
	366	static void loopback_disable(struct usb_function *f)
	367	{
	368	struct f_loopback *loop = func_to_loop(f);
	369
	370	disable_loopback(loop);
	371	}
	372
cf9a08ae	373	static struct usb_function loopback_alloc(struct usb_function_instance fi)
e5760fda DB	374	{
e5760fda DB	375	struct f_loopback *loop;
cf9a08ae	376	struct f_lb_opts *lb_opts;
e5760fda DB	377
	378	loop = kzalloc(sizeof *loop, GFP_KERNEL);
	379	if (!loop)
cf9a08ae SAS	380	return ERR_PTR(-ENOMEM);
	381
	382	lb_opts = container_of(fi, struct f_lb_opts, func_inst);
	383	buflen = lb_opts->bulk_buflen;
	384	qlen = lb_opts->qlen;
	385	if (!qlen)
	386	qlen = 32;
e5760fda DB	387
e5760fda DB	388	loop->function.name = "loopback";
e5760fda	389	loop->function.bind = loopback_bind;
e5760fda DB	390	loop->function.set_alt = loopback_set_alt;
e5760fda DB	391	loop->function.disable = loopback_disable;
cf9a08ae SAS	392	loop->function.strings = loopback_strings;
	393
	394	loop->function.free_func = lb_free_func;
	395
	396	return &loop->function;
	397	}
	398
	399	static void lb_free_instance(struct usb_function_instance *fi)
	400	{
	401	struct f_lb_opts *lb_opts;
e5760fda	402
cf9a08ae SAS	403	lb_opts = container_of(fi, struct f_lb_opts, func_inst);
cf9a08ae SAS	404	kfree(lb_opts);
e5760fda	405	}
cf9a08ae SAS	406
	407	static struct usb_function_instance *loopback_alloc_instance(void)
	408	{
	409	struct f_lb_opts *lb_opts;
	410
	411	lb_opts = kzalloc(sizeof(*lb_opts), GFP_KERNEL);
	412	if (!lb_opts)
	413	return ERR_PTR(-ENOMEM);
	414	lb_opts->func_inst.free_func_inst = lb_free_instance;
	415	return &lb_opts->func_inst;
	416	}
	417	DECLARE_USB_FUNCTION(Loopback, loopback_alloc_instance, loopback_alloc);
	418
	419	int __init lb_modinit(void)
	420	{
	421	int ret;
	422
	423	ret = usb_function_register(&Loopbackusb_func);
	424	if (ret)
	425	return ret;
	426	return ret;
	427	}
	428	void __exit lb_modexit(void)
	429	{
	430	usb_function_unregister(&Loopbackusb_func);
	431	}
	432
	433	MODULE_LICENSE("GPL");