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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
13/* #define VERBOSE_DEBUG */
14
15#include <linux/slab.h>
16#include <linux/kernel.h>
17#include <linux/device.h>
18#include <linux/module.h>
19#include <linux/err.h>
20#include <linux/usb/composite.h>
21
22#include "g_zero.h"
23#include "u_f.h"
24
25/*
26 * LOOPBACK FUNCTION ... a testing vehicle for USB peripherals,
27 *
28 * This takes messages of various sizes written OUT to a device, and loops
29 * them back so they can be read IN from it. It has been used by certain
30 * test applications. It supports limited testing of data queueing logic.
31 *
32 *
33 * This is currently packaged as a configuration driver, which can't be
34 * combined with other functions to make composite devices. However, it
35 * can be combined with other independent configurations.
36 */
37struct f_loopback {
38 struct usb_function function;
39
40 struct usb_ep *in_ep;
41 struct usb_ep *out_ep;
42};
43
44static inline struct f_loopback *func_to_loop(struct usb_function *f)
45{
46 return container_of(f, struct f_loopback, function);
47}
48
49static unsigned qlen;
50static unsigned buflen;
51
52/*-------------------------------------------------------------------------*/
53
54static struct usb_interface_descriptor loopback_intf = {
55 .bLength = sizeof loopback_intf,
56 .bDescriptorType = USB_DT_INTERFACE,
57
58 .bNumEndpoints = 2,
59 .bInterfaceClass = USB_CLASS_VENDOR_SPEC,
60 /* .iInterface = DYNAMIC */
61};
62
63/* full speed support: */
64
65static struct usb_endpoint_descriptor fs_loop_source_desc = {
66 .bLength = USB_DT_ENDPOINT_SIZE,
67 .bDescriptorType = USB_DT_ENDPOINT,
68
69 .bEndpointAddress = USB_DIR_IN,
70 .bmAttributes = USB_ENDPOINT_XFER_BULK,
71};
72
73static struct usb_endpoint_descriptor fs_loop_sink_desc = {
74 .bLength = USB_DT_ENDPOINT_SIZE,
75 .bDescriptorType = USB_DT_ENDPOINT,
76
77 .bEndpointAddress = USB_DIR_OUT,
78 .bmAttributes = USB_ENDPOINT_XFER_BULK,
79};
80
81static struct usb_descriptor_header *fs_loopback_descs[] = {
82 (struct usb_descriptor_header *) &loopback_intf,
83 (struct usb_descriptor_header *) &fs_loop_sink_desc,
84 (struct usb_descriptor_header *) &fs_loop_source_desc,
85 NULL,
86};
87
88/* high speed support: */
89
90static struct usb_endpoint_descriptor hs_loop_source_desc = {
91 .bLength = USB_DT_ENDPOINT_SIZE,
92 .bDescriptorType = USB_DT_ENDPOINT,
93
94 .bmAttributes = USB_ENDPOINT_XFER_BULK,
95 .wMaxPacketSize = cpu_to_le16(512),
96};
97
98static struct usb_endpoint_descriptor hs_loop_sink_desc = {
99 .bLength = USB_DT_ENDPOINT_SIZE,
100 .bDescriptorType = USB_DT_ENDPOINT,
101
102 .bmAttributes = USB_ENDPOINT_XFER_BULK,
103 .wMaxPacketSize = cpu_to_le16(512),
104};
105
106static struct usb_descriptor_header *hs_loopback_descs[] = {
107 (struct usb_descriptor_header *) &loopback_intf,
108 (struct usb_descriptor_header *) &hs_loop_source_desc,
109 (struct usb_descriptor_header *) &hs_loop_sink_desc,
110 NULL,
111};
112
113/* super speed support: */
114
115static struct usb_endpoint_descriptor ss_loop_source_desc = {
116 .bLength = USB_DT_ENDPOINT_SIZE,
117 .bDescriptorType = USB_DT_ENDPOINT,
118
119 .bmAttributes = USB_ENDPOINT_XFER_BULK,
120 .wMaxPacketSize = cpu_to_le16(1024),
121};
122
123static struct usb_ss_ep_comp_descriptor ss_loop_source_comp_desc = {
124 .bLength = USB_DT_SS_EP_COMP_SIZE,
125 .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
126 .bMaxBurst = 0,
127 .bmAttributes = 0,
128 .wBytesPerInterval = 0,
129};
130
131static struct usb_endpoint_descriptor ss_loop_sink_desc = {
132 .bLength = USB_DT_ENDPOINT_SIZE,
133 .bDescriptorType = USB_DT_ENDPOINT,
134
135 .bmAttributes = USB_ENDPOINT_XFER_BULK,
136 .wMaxPacketSize = cpu_to_le16(1024),
137};
138
139static struct usb_ss_ep_comp_descriptor ss_loop_sink_comp_desc = {
140 .bLength = USB_DT_SS_EP_COMP_SIZE,
141 .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
142 .bMaxBurst = 0,
143 .bmAttributes = 0,
144 .wBytesPerInterval = 0,
145};
146
147static struct usb_descriptor_header *ss_loopback_descs[] = {
148 (struct usb_descriptor_header *) &loopback_intf,
149 (struct usb_descriptor_header *) &ss_loop_source_desc,
150 (struct usb_descriptor_header *) &ss_loop_source_comp_desc,
151 (struct usb_descriptor_header *) &ss_loop_sink_desc,
152 (struct usb_descriptor_header *) &ss_loop_sink_comp_desc,
153 NULL,
154};
155
156/* function-specific strings: */
157
158static struct usb_string strings_loopback[] = {
159 [0].s = "loop input to output",
160 { } /* end of list */
161};
162
163static struct usb_gadget_strings stringtab_loop = {
164 .language = 0x0409, /* en-us */
165 .strings = strings_loopback,
166};
167
168static struct usb_gadget_strings *loopback_strings[] = {
169 &stringtab_loop,
170 NULL,
171};
172
173/*-------------------------------------------------------------------------*/
174
175static int loopback_bind(struct usb_configuration *c, struct usb_function *f)
176{
177 struct usb_composite_dev *cdev = c->cdev;
178 struct f_loopback *loop = func_to_loop(f);
179 int id;
180 int ret;
181
182 /* allocate interface ID(s) */
183 id = usb_interface_id(c, f);
184 if (id < 0)
185 return id;
186 loopback_intf.bInterfaceNumber = id;
187
188 id = usb_string_id(cdev);
189 if (id < 0)
190 return id;
191 strings_loopback[0].id = id;
192 loopback_intf.iInterface = id;
193
194 /* allocate endpoints */
195
196 loop->in_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_source_desc);
197 if (!loop->in_ep) {
198autoconf_fail:
199 ERROR(cdev, "%s: can't autoconfigure on %s\n",
200 f->name, cdev->gadget->name);
201 return -ENODEV;
202 }
203 loop->in_ep->driver_data = cdev; /* claim */
204
205 loop->out_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_sink_desc);
206 if (!loop->out_ep)
207 goto autoconf_fail;
208 loop->out_ep->driver_data = cdev; /* claim */
209
210 /* support high speed hardware */
211 hs_loop_source_desc.bEndpointAddress =
212 fs_loop_source_desc.bEndpointAddress;
213 hs_loop_sink_desc.bEndpointAddress = fs_loop_sink_desc.bEndpointAddress;
214
215 /* support super speed hardware */
216 ss_loop_source_desc.bEndpointAddress =
217 fs_loop_source_desc.bEndpointAddress;
218 ss_loop_sink_desc.bEndpointAddress = fs_loop_sink_desc.bEndpointAddress;
219
220 ret = usb_assign_descriptors(f, fs_loopback_descs, hs_loopback_descs,
221 ss_loopback_descs);
222 if (ret)
223 return ret;
224
225 DBG(cdev, "%s speed %s: IN/%s, OUT/%s\n",
226 (gadget_is_superspeed(c->cdev->gadget) ? "super" :
227 (gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full")),
228 f->name, loop->in_ep->name, loop->out_ep->name);
229 return 0;
230}
231
232static void lb_free_func(struct usb_function *f)
233{
234 struct f_lb_opts *opts;
235
236 opts = container_of(f->fi, struct f_lb_opts, func_inst);
237
238 mutex_lock(&opts->lock);
239 opts->refcnt--;
240 mutex_unlock(&opts->lock);
241
242 usb_free_all_descriptors(f);
243 kfree(func_to_loop(f));
244}
245
246static void loopback_complete(struct usb_ep *ep, struct usb_request *req)
247{
248 struct f_loopback *loop = ep->driver_data;
249 struct usb_composite_dev *cdev = loop->function.config->cdev;
250 int status = req->status;
251
252 switch (status) {
253
254 case 0: /* normal completion? */
255 if (ep == loop->out_ep) {
256 /* loop this OUT packet back IN to the host */
257 req->zero = (req->actual < req->length);
258 req->length = req->actual;
259 status = usb_ep_queue(loop->in_ep, req, GFP_ATOMIC);
260 if (status == 0)
261 return;
262
263 /* "should never get here" */
264 ERROR(cdev, "can't loop %s to %s: %d\n",
265 ep->name, loop->in_ep->name,
266 status);
267 }
268
269 /* queue the buffer for some later OUT packet */
270 req->length = buflen;
271 status = usb_ep_queue(loop->out_ep, req, GFP_ATOMIC);
272 if (status == 0)
273 return;
274
275 /* "should never get here" */
276 /* FALLTHROUGH */
277
278 default:
279 ERROR(cdev, "%s loop complete --> %d, %d/%d\n", ep->name,
280 status, req->actual, req->length);
281 /* FALLTHROUGH */
282
283 /* NOTE: since this driver doesn't maintain an explicit record
284 * of requests it submitted (just maintains qlen count), we
285 * rely on the hardware driver to clean up on disconnect or
286 * endpoint disable.
287 */
288 case -ECONNABORTED: /* hardware forced ep reset */
289 case -ECONNRESET: /* request dequeued */
290 case -ESHUTDOWN: /* disconnect from host */
291 free_ep_req(ep, req);
292 return;
293 }
294}
295
296static void disable_loopback(struct f_loopback *loop)
297{
298 struct usb_composite_dev *cdev;
299
300 cdev = loop->function.config->cdev;
301 disable_endpoints(cdev, loop->in_ep, loop->out_ep, NULL, NULL);
302 VDBG(cdev, "%s disabled\n", loop->function.name);
303}
304
305static inline struct usb_request *lb_alloc_ep_req(struct usb_ep *ep, int len)
306{
307 return alloc_ep_req(ep, len, buflen);
308}
309
310static int
311enable_loopback(struct usb_composite_dev *cdev, struct f_loopback *loop)
312{
313 int result = 0;
314 struct usb_ep *ep;
315 struct usb_request *req;
316 unsigned i;
317
318 /* one endpoint writes data back IN to the host */
319 ep = loop->in_ep;
320 result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
321 if (result)
322 return result;
323 result = usb_ep_enable(ep);
324 if (result < 0)
325 return result;
326 ep->driver_data = loop;
327
328 /* one endpoint just reads OUT packets */
329 ep = loop->out_ep;
330 result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
331 if (result)
332 goto fail0;
333
334 result = usb_ep_enable(ep);
335 if (result < 0) {
336fail0:
337 ep = loop->in_ep;
338 usb_ep_disable(ep);
339 ep->driver_data = NULL;
340 return result;
341 }
342 ep->driver_data = loop;
343
344 /* allocate a bunch of read buffers and queue them all at once.
345 * we buffer at most 'qlen' transfers; fewer if any need more
346 * than 'buflen' bytes each.
347 */
348 for (i = 0; i < qlen && result == 0; i++) {
349 req = lb_alloc_ep_req(ep, 0);
350 if (req) {
351 req->complete = loopback_complete;
352 result = usb_ep_queue(ep, req, GFP_ATOMIC);
353 if (result)
354 ERROR(cdev, "%s queue req --> %d\n",
355 ep->name, result);
356 } else {
357 usb_ep_disable(ep);
358 ep->driver_data = NULL;
359 result = -ENOMEM;
360 goto fail0;
361 }
362 }
363
364 DBG(cdev, "%s enabled\n", loop->function.name);
365 return result;
366}
367
368static int loopback_set_alt(struct usb_function *f,
369 unsigned intf, unsigned alt)
370{
371 struct f_loopback *loop = func_to_loop(f);
372 struct usb_composite_dev *cdev = f->config->cdev;
373
374 /* we know alt is zero */
375 if (loop->in_ep->driver_data)
376 disable_loopback(loop);
377 return enable_loopback(cdev, loop);
378}
379
380static void loopback_disable(struct usb_function *f)
381{
382 struct f_loopback *loop = func_to_loop(f);
383
384 disable_loopback(loop);
385}
386
387static struct usb_function *loopback_alloc(struct usb_function_instance *fi)
388{
389 struct f_loopback *loop;
390 struct f_lb_opts *lb_opts;
391
392 loop = kzalloc(sizeof *loop, GFP_KERNEL);
393 if (!loop)
394 return ERR_PTR(-ENOMEM);
395
396 lb_opts = container_of(fi, struct f_lb_opts, func_inst);
397
398 mutex_lock(&lb_opts->lock);
399 lb_opts->refcnt++;
400 mutex_unlock(&lb_opts->lock);
401
402 buflen = lb_opts->bulk_buflen;
403 qlen = lb_opts->qlen;
404 if (!qlen)
405 qlen = 32;
406
407 loop->function.name = "loopback";
408 loop->function.bind = loopback_bind;
409 loop->function.set_alt = loopback_set_alt;
410 loop->function.disable = loopback_disable;
411 loop->function.strings = loopback_strings;
412
413 loop->function.free_func = lb_free_func;
414
415 return &loop->function;
416}
417
418static inline struct f_lb_opts *to_f_lb_opts(struct config_item *item)
419{
420 return container_of(to_config_group(item), struct f_lb_opts,
421 func_inst.group);
422}
423
424CONFIGFS_ATTR_STRUCT(f_lb_opts);
425CONFIGFS_ATTR_OPS(f_lb_opts);
426
427static void lb_attr_release(struct config_item *item)
428{
429 struct f_lb_opts *lb_opts = to_f_lb_opts(item);
430
431 usb_put_function_instance(&lb_opts->func_inst);
432}
433
434static struct configfs_item_operations lb_item_ops = {
435 .release = lb_attr_release,
436 .show_attribute = f_lb_opts_attr_show,
437 .store_attribute = f_lb_opts_attr_store,
438};
439
440static ssize_t f_lb_opts_qlen_show(struct f_lb_opts *opts, char *page)
441{
442 int result;
443
444 mutex_lock(&opts->lock);
445 result = sprintf(page, "%d", opts->qlen);
446 mutex_unlock(&opts->lock);
447
448 return result;
449}
450
451static ssize_t f_lb_opts_qlen_store(struct f_lb_opts *opts,
452 const char *page, size_t len)
453{
454 int ret;
455 u32 num;
456
457 mutex_lock(&opts->lock);
458 if (opts->refcnt) {
459 ret = -EBUSY;
460 goto end;
461 }
462
463 ret = kstrtou32(page, 0, &num);
464 if (ret)
465 goto end;
466
467 opts->qlen = num;
468 ret = len;
469end:
470 mutex_unlock(&opts->lock);
471 return ret;
472}
473
474static struct f_lb_opts_attribute f_lb_opts_qlen =
475 __CONFIGFS_ATTR(qlen, S_IRUGO | S_IWUSR,
476 f_lb_opts_qlen_show,
477 f_lb_opts_qlen_store);
478
479static ssize_t f_lb_opts_bulk_buflen_show(struct f_lb_opts *opts, char *page)
480{
481 int result;
482
483 mutex_lock(&opts->lock);
484 result = sprintf(page, "%d", opts->bulk_buflen);
485 mutex_unlock(&opts->lock);
486
487 return result;
488}
489
490static ssize_t f_lb_opts_bulk_buflen_store(struct f_lb_opts *opts,
491 const char *page, size_t len)
492{
493 int ret;
494 u32 num;
495
496 mutex_lock(&opts->lock);
497 if (opts->refcnt) {
498 ret = -EBUSY;
499 goto end;
500 }
501
502 ret = kstrtou32(page, 0, &num);
503 if (ret)
504 goto end;
505
506 opts->bulk_buflen = num;
507 ret = len;
508end:
509 mutex_unlock(&opts->lock);
510 return ret;
511}
512
513static struct f_lb_opts_attribute f_lb_opts_bulk_buflen =
514 __CONFIGFS_ATTR(buflen, S_IRUGO | S_IWUSR,
515 f_lb_opts_bulk_buflen_show,
516 f_lb_opts_bulk_buflen_store);
517
518static struct configfs_attribute *lb_attrs[] = {
519 &f_lb_opts_qlen.attr,
520 &f_lb_opts_bulk_buflen.attr,
521 NULL,
522};
523
524static struct config_item_type lb_func_type = {
525 .ct_item_ops = &lb_item_ops,
526 .ct_attrs = lb_attrs,
527 .ct_owner = THIS_MODULE,
528};
529
530static void lb_free_instance(struct usb_function_instance *fi)
531{
532 struct f_lb_opts *lb_opts;
533
534 lb_opts = container_of(fi, struct f_lb_opts, func_inst);
535 kfree(lb_opts);
536}
537
538static struct usb_function_instance *loopback_alloc_instance(void)
539{
540 struct f_lb_opts *lb_opts;
541
542 lb_opts = kzalloc(sizeof(*lb_opts), GFP_KERNEL);
543 if (!lb_opts)
544 return ERR_PTR(-ENOMEM);
545 mutex_init(&lb_opts->lock);
546 lb_opts->func_inst.free_func_inst = lb_free_instance;
547 lb_opts->bulk_buflen = GZERO_BULK_BUFLEN;
548 lb_opts->qlen = GZERO_QLEN;
549
550 config_group_init_type_name(&lb_opts->func_inst.group, "",
551 &lb_func_type);
552
553 return &lb_opts->func_inst;
554}
555DECLARE_USB_FUNCTION(Loopback, loopback_alloc_instance, loopback_alloc);
556
557int __init lb_modinit(void)
558{
559 int ret;
560
561 ret = usb_function_register(&Loopbackusb_func);
562 if (ret)
563 return ret;
564 return ret;
565}
566void __exit lb_modexit(void)
567{
568 usb_function_unregister(&Loopbackusb_func);
569}
570
571MODULE_LICENSE("GPL");