2 * f_loopback.c - USB peripheral loopback configuration driver
4 * Copyright (C) 2003-2008 David Brownell
5 * Copyright (C) 2008 by Nokia Corporation
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.
13 /* #define VERBOSE_DEBUG */
15 #include <linux/slab.h>
16 #include <linux/kernel.h>
17 #include <linux/device.h>
20 #include "gadget_chips.h"
24 * LOOPBACK FUNCTION ... a testing vehicle for USB peripherals,
26 * This takes messages of various sizes written OUT to a device, and loops
27 * them back so they can be read IN from it. It has been used by certain
28 * test applications. It supports limited testing of data queueing logic.
31 * This is currently packaged as a configuration driver, which can't be
32 * combined with other functions to make composite devices. However, it
33 * can be combined with other independent configurations.
36 struct usb_function function;
39 struct usb_ep *out_ep;
42 static inline struct f_loopback *func_to_loop(struct usb_function *f)
44 return container_of(f, struct f_loopback, function);
47 static unsigned qlen = 32;
48 module_param(qlen, uint, 0);
49 MODULE_PARM_DESC(qlenn, "depth of loopback queue");
51 /*-------------------------------------------------------------------------*/
53 static struct usb_interface_descriptor loopback_intf = {
54 .bLength = sizeof loopback_intf,
55 .bDescriptorType = USB_DT_INTERFACE,
58 .bInterfaceClass = USB_CLASS_VENDOR_SPEC,
59 /* .iInterface = DYNAMIC */
62 /* full speed support: */
64 static struct usb_endpoint_descriptor fs_loop_source_desc = {
65 .bLength = USB_DT_ENDPOINT_SIZE,
66 .bDescriptorType = USB_DT_ENDPOINT,
68 .bEndpointAddress = USB_DIR_IN,
69 .bmAttributes = USB_ENDPOINT_XFER_BULK,
72 static struct usb_endpoint_descriptor fs_loop_sink_desc = {
73 .bLength = USB_DT_ENDPOINT_SIZE,
74 .bDescriptorType = USB_DT_ENDPOINT,
76 .bEndpointAddress = USB_DIR_OUT,
77 .bmAttributes = USB_ENDPOINT_XFER_BULK,
80 static struct usb_descriptor_header *fs_loopback_descs[] = {
81 (struct usb_descriptor_header *) &loopback_intf,
82 (struct usb_descriptor_header *) &fs_loop_sink_desc,
83 (struct usb_descriptor_header *) &fs_loop_source_desc,
87 /* high speed support: */
89 static struct usb_endpoint_descriptor hs_loop_source_desc = {
90 .bLength = USB_DT_ENDPOINT_SIZE,
91 .bDescriptorType = USB_DT_ENDPOINT,
93 .bmAttributes = USB_ENDPOINT_XFER_BULK,
94 .wMaxPacketSize = cpu_to_le16(512),
97 static struct usb_endpoint_descriptor hs_loop_sink_desc = {
98 .bLength = USB_DT_ENDPOINT_SIZE,
99 .bDescriptorType = USB_DT_ENDPOINT,
101 .bmAttributes = USB_ENDPOINT_XFER_BULK,
102 .wMaxPacketSize = cpu_to_le16(512),
105 static struct usb_descriptor_header *hs_loopback_descs[] = {
106 (struct usb_descriptor_header *) &loopback_intf,
107 (struct usb_descriptor_header *) &hs_loop_source_desc,
108 (struct usb_descriptor_header *) &hs_loop_sink_desc,
112 /* super speed support: */
114 static struct usb_endpoint_descriptor ss_loop_source_desc = {
115 .bLength = USB_DT_ENDPOINT_SIZE,
116 .bDescriptorType = USB_DT_ENDPOINT,
118 .bmAttributes = USB_ENDPOINT_XFER_BULK,
119 .wMaxPacketSize = cpu_to_le16(1024),
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,
127 .wBytesPerInterval = 0,
130 static struct usb_endpoint_descriptor ss_loop_sink_desc = {
131 .bLength = USB_DT_ENDPOINT_SIZE,
132 .bDescriptorType = USB_DT_ENDPOINT,
134 .bmAttributes = USB_ENDPOINT_XFER_BULK,
135 .wMaxPacketSize = cpu_to_le16(1024),
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,
143 .wBytesPerInterval = 0,
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,
155 /* function-specific strings: */
157 static struct usb_string strings_loopback[] = {
158 [0].s = "loop input to output",
159 { } /* end of list */
162 static struct usb_gadget_strings stringtab_loop = {
163 .language = 0x0409, /* en-us */
164 .strings = strings_loopback,
167 static struct usb_gadget_strings *loopback_strings[] = {
172 /*-------------------------------------------------------------------------*/
175 loopback_bind(struct usb_configuration *c, struct usb_function *f)
177 struct usb_composite_dev *cdev = c->cdev;
178 struct f_loopback *loop = func_to_loop(f);
182 /* allocate interface ID(s) */
183 id = usb_interface_id(c, f);
186 loopback_intf.bInterfaceNumber = id;
188 /* allocate endpoints */
190 loop->in_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_source_desc);
193 ERROR(cdev, "%s: can't autoconfigure on %s\n",
194 f->name, cdev->gadget->name);
197 loop->in_ep->driver_data = cdev; /* claim */
199 loop->out_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_sink_desc);
202 loop->out_ep->driver_data = cdev; /* claim */
204 /* support high speed hardware */
205 hs_loop_source_desc.bEndpointAddress =
206 fs_loop_source_desc.bEndpointAddress;
207 hs_loop_sink_desc.bEndpointAddress = fs_loop_sink_desc.bEndpointAddress;
209 /* support super speed hardware */
210 ss_loop_source_desc.bEndpointAddress =
211 fs_loop_source_desc.bEndpointAddress;
212 ss_loop_sink_desc.bEndpointAddress = fs_loop_sink_desc.bEndpointAddress;
214 ret = usb_assign_descriptors(f, fs_loopback_descs, hs_loopback_descs,
219 DBG(cdev, "%s speed %s: IN/%s, OUT/%s\n",
220 (gadget_is_superspeed(c->cdev->gadget) ? "super" :
221 (gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full")),
222 f->name, loop->in_ep->name, loop->out_ep->name);
227 loopback_unbind(struct usb_configuration *c, struct usb_function *f)
229 usb_free_all_descriptors(f);
230 kfree(func_to_loop(f));
233 static void loopback_complete(struct usb_ep *ep, struct usb_request *req)
235 struct f_loopback *loop = ep->driver_data;
236 struct usb_composite_dev *cdev = loop->function.config->cdev;
237 int status = req->status;
241 case 0: /* normal completion? */
242 if (ep == loop->out_ep) {
243 /* loop this OUT packet back IN to the host */
244 req->zero = (req->actual < req->length);
245 req->length = req->actual;
246 status = usb_ep_queue(loop->in_ep, req, GFP_ATOMIC);
250 /* "should never get here" */
251 ERROR(cdev, "can't loop %s to %s: %d\n",
252 ep->name, loop->in_ep->name,
256 /* queue the buffer for some later OUT packet */
257 req->length = buflen;
258 status = usb_ep_queue(loop->out_ep, req, GFP_ATOMIC);
262 /* "should never get here" */
266 ERROR(cdev, "%s loop complete --> %d, %d/%d\n", ep->name,
267 status, req->actual, req->length);
270 /* NOTE: since this driver doesn't maintain an explicit record
271 * of requests it submitted (just maintains qlen count), we
272 * rely on the hardware driver to clean up on disconnect or
275 case -ECONNABORTED: /* hardware forced ep reset */
276 case -ECONNRESET: /* request dequeued */
277 case -ESHUTDOWN: /* disconnect from host */
278 free_ep_req(ep, req);
283 static void disable_loopback(struct f_loopback *loop)
285 struct usb_composite_dev *cdev;
287 cdev = loop->function.config->cdev;
288 disable_endpoints(cdev, loop->in_ep, loop->out_ep, NULL, NULL);
289 VDBG(cdev, "%s disabled\n", loop->function.name);
293 enable_loopback(struct usb_composite_dev *cdev, struct f_loopback *loop)
297 struct usb_request *req;
300 /* one endpoint writes data back IN to the host */
302 result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
305 result = usb_ep_enable(ep);
308 ep->driver_data = loop;
310 /* one endpoint just reads OUT packets */
312 result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
316 result = usb_ep_enable(ep);
321 ep->driver_data = NULL;
324 ep->driver_data = loop;
326 /* allocate a bunch of read buffers and queue them all at once.
327 * we buffer at most 'qlen' transfers; fewer if any need more
328 * than 'buflen' bytes each.
330 for (i = 0; i < qlen && result == 0; i++) {
331 req = alloc_ep_req(ep, 0);
333 req->complete = loopback_complete;
334 result = usb_ep_queue(ep, req, GFP_ATOMIC);
336 ERROR(cdev, "%s queue req --> %d\n",
340 ep->driver_data = NULL;
346 DBG(cdev, "%s enabled\n", loop->function.name);
350 static int loopback_set_alt(struct usb_function *f,
351 unsigned intf, unsigned alt)
353 struct f_loopback *loop = func_to_loop(f);
354 struct usb_composite_dev *cdev = f->config->cdev;
356 /* we know alt is zero */
357 if (loop->in_ep->driver_data)
358 disable_loopback(loop);
359 return enable_loopback(cdev, loop);
362 static void loopback_disable(struct usb_function *f)
364 struct f_loopback *loop = func_to_loop(f);
366 disable_loopback(loop);
369 /*-------------------------------------------------------------------------*/
371 static int __init loopback_bind_config(struct usb_configuration *c)
373 struct f_loopback *loop;
376 loop = kzalloc(sizeof *loop, GFP_KERNEL);
380 loop->function.name = "loopback";
381 loop->function.bind = loopback_bind;
382 loop->function.unbind = loopback_unbind;
383 loop->function.set_alt = loopback_set_alt;
384 loop->function.disable = loopback_disable;
386 status = usb_add_function(c, &loop->function);
392 static struct usb_configuration loopback_driver = {
394 .strings = loopback_strings,
395 .bConfigurationValue = 2,
396 .bmAttributes = USB_CONFIG_ATT_SELFPOWER,
397 /* .iConfiguration = DYNAMIC */
401 * loopback_add - add a loopback testing configuration to a device
402 * @cdev: the device to support the loopback configuration
404 int __init loopback_add(struct usb_composite_dev *cdev, bool autoresume)
408 /* allocate string ID(s) */
409 id = usb_string_id(cdev);
412 strings_loopback[0].id = id;
414 loopback_intf.iInterface = id;
415 loopback_driver.iConfiguration = id;
417 /* support autoresume for remote wakeup testing */
419 loopback_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
421 /* support OTG systems */
422 if (gadget_is_otg(cdev->gadget)) {
423 loopback_driver.descriptors = otg_desc;
424 loopback_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
427 return usb_add_config(cdev, &loopback_driver, loopback_bind_config);