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 struct f_loopback { 33 struct usb_function function; 34 35 struct usb_ep *in_ep; 36 struct usb_ep *out_ep; 37 }; 38 39 static inline struct f_loopback *func_to_loop(struct usb_function *f) 40 { 41 return container_of(f, struct f_loopback, function); 42 } 43 44 static unsigned qlen; 45 static unsigned buflen; 46 47 /*-------------------------------------------------------------------------*/ 48 49 static struct usb_interface_descriptor loopback_intf = { 50 .bLength = sizeof loopback_intf, 51 .bDescriptorType = USB_DT_INTERFACE, 52 53 .bNumEndpoints = 2, 54 .bInterfaceClass = USB_CLASS_VENDOR_SPEC, 55 /* .iInterface = DYNAMIC */ 56 }; 57 58 /* full speed support: */ 59 60 static struct usb_endpoint_descriptor fs_loop_source_desc = { 61 .bLength = USB_DT_ENDPOINT_SIZE, 62 .bDescriptorType = USB_DT_ENDPOINT, 63 64 .bEndpointAddress = USB_DIR_IN, 65 .bmAttributes = USB_ENDPOINT_XFER_BULK, 66 }; 67 68 static struct usb_endpoint_descriptor fs_loop_sink_desc = { 69 .bLength = USB_DT_ENDPOINT_SIZE, 70 .bDescriptorType = USB_DT_ENDPOINT, 71 72 .bEndpointAddress = USB_DIR_OUT, 73 .bmAttributes = USB_ENDPOINT_XFER_BULK, 74 }; 75 76 static struct usb_descriptor_header *fs_loopback_descs[] = { 77 (struct usb_descriptor_header *) &loopback_intf, 78 (struct usb_descriptor_header *) &fs_loop_sink_desc, 79 (struct usb_descriptor_header *) &fs_loop_source_desc, 80 NULL, 81 }; 82 83 /* high speed support: */ 84 85 static struct usb_endpoint_descriptor hs_loop_source_desc = { 86 .bLength = USB_DT_ENDPOINT_SIZE, 87 .bDescriptorType = USB_DT_ENDPOINT, 88 89 .bmAttributes = USB_ENDPOINT_XFER_BULK, 90 .wMaxPacketSize = cpu_to_le16(512), 91 }; 92 93 static struct usb_endpoint_descriptor hs_loop_sink_desc = { 94 .bLength = USB_DT_ENDPOINT_SIZE, 95 .bDescriptorType = USB_DT_ENDPOINT, 96 97 .bmAttributes = USB_ENDPOINT_XFER_BULK, 98 .wMaxPacketSize = cpu_to_le16(512), 99 }; 100 101 static struct usb_descriptor_header *hs_loopback_descs[] = { 102 (struct usb_descriptor_header *) &loopback_intf, 103 (struct usb_descriptor_header *) &hs_loop_source_desc, 104 (struct usb_descriptor_header *) &hs_loop_sink_desc, 105 NULL, 106 }; 107 108 /* super speed support: */ 109 110 static struct usb_endpoint_descriptor ss_loop_source_desc = { 111 .bLength = USB_DT_ENDPOINT_SIZE, 112 .bDescriptorType = USB_DT_ENDPOINT, 113 114 .bmAttributes = USB_ENDPOINT_XFER_BULK, 115 .wMaxPacketSize = cpu_to_le16(1024), 116 }; 117 118 static struct usb_ss_ep_comp_descriptor ss_loop_source_comp_desc = { 119 .bLength = USB_DT_SS_EP_COMP_SIZE, 120 .bDescriptorType = USB_DT_SS_ENDPOINT_COMP, 121 .bMaxBurst = 0, 122 .bmAttributes = 0, 123 .wBytesPerInterval = 0, 124 }; 125 126 static struct usb_endpoint_descriptor ss_loop_sink_desc = { 127 .bLength = USB_DT_ENDPOINT_SIZE, 128 .bDescriptorType = USB_DT_ENDPOINT, 129 130 .bmAttributes = USB_ENDPOINT_XFER_BULK, 131 .wMaxPacketSize = cpu_to_le16(1024), 132 }; 133 134 static struct usb_ss_ep_comp_descriptor ss_loop_sink_comp_desc = { 135 .bLength = USB_DT_SS_EP_COMP_SIZE, 136 .bDescriptorType = USB_DT_SS_ENDPOINT_COMP, 137 .bMaxBurst = 0, 138 .bmAttributes = 0, 139 .wBytesPerInterval = 0, 140 }; 141 142 static struct usb_descriptor_header *ss_loopback_descs[] = { 143 (struct usb_descriptor_header *) &loopback_intf, 144 (struct usb_descriptor_header *) &ss_loop_source_desc, 145 (struct usb_descriptor_header *) &ss_loop_source_comp_desc, 146 (struct usb_descriptor_header *) &ss_loop_sink_desc, 147 (struct usb_descriptor_header *) &ss_loop_sink_comp_desc, 148 NULL, 149 }; 150 151 /* function-specific strings: */ 152 153 static struct usb_string strings_loopback[] = { 154 [0].s = "loop input to output", 155 { } /* end of list */ 156 }; 157 158 static struct usb_gadget_strings stringtab_loop = { 159 .language = 0x0409, /* en-us */ 160 .strings = strings_loopback, 161 }; 162 163 static struct usb_gadget_strings *loopback_strings[] = { 164 &stringtab_loop, 165 NULL, 166 }; 167 168 /*-------------------------------------------------------------------------*/ 169 170 static int loopback_bind(struct usb_configuration *c, struct usb_function *f) 171 { 172 struct usb_composite_dev *cdev = c->cdev; 173 struct f_loopback *loop = func_to_loop(f); 174 int id; 175 int ret; 176 177 /* allocate interface ID(s) */ 178 id = usb_interface_id(c, f); 179 if (id < 0) 180 return id; 181 loopback_intf.bInterfaceNumber = id; 182 183 id = usb_string_id(cdev); 184 if (id < 0) 185 return id; 186 strings_loopback[0].id = id; 187 loopback_intf.iInterface = id; 188 189 /* allocate endpoints */ 190 191 loop->in_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_source_desc); 192 if (!loop->in_ep) { 193 autoconf_fail: 194 ERROR(cdev, "%s: can't autoconfigure on %s\n", 195 f->name, cdev->gadget->name); 196 return -ENODEV; 197 } 198 199 loop->out_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_sink_desc); 200 if (!loop->out_ep) 201 goto autoconf_fail; 202 203 /* support high speed hardware */ 204 hs_loop_source_desc.bEndpointAddress = 205 fs_loop_source_desc.bEndpointAddress; 206 hs_loop_sink_desc.bEndpointAddress = fs_loop_sink_desc.bEndpointAddress; 207 208 /* support super speed hardware */ 209 ss_loop_source_desc.bEndpointAddress = 210 fs_loop_source_desc.bEndpointAddress; 211 ss_loop_sink_desc.bEndpointAddress = fs_loop_sink_desc.bEndpointAddress; 212 213 ret = usb_assign_descriptors(f, fs_loopback_descs, hs_loopback_descs, 214 ss_loopback_descs); 215 if (ret) 216 return ret; 217 218 DBG(cdev, "%s speed %s: IN/%s, OUT/%s\n", 219 (gadget_is_superspeed(c->cdev->gadget) ? "super" : 220 (gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full")), 221 f->name, loop->in_ep->name, loop->out_ep->name); 222 return 0; 223 } 224 225 static void lb_free_func(struct usb_function *f) 226 { 227 struct f_lb_opts *opts; 228 229 opts = container_of(f->fi, struct f_lb_opts, func_inst); 230 231 mutex_lock(&opts->lock); 232 opts->refcnt--; 233 mutex_unlock(&opts->lock); 234 235 usb_free_all_descriptors(f); 236 kfree(func_to_loop(f)); 237 } 238 239 static void loopback_complete(struct usb_ep *ep, struct usb_request *req) 240 { 241 struct f_loopback *loop = ep->driver_data; 242 struct usb_composite_dev *cdev = loop->function.config->cdev; 243 int status = req->status; 244 245 switch (status) { 246 247 case 0: /* normal completion? */ 248 if (ep == loop->out_ep) { 249 req->zero = (req->actual < req->length); 250 req->length = req->actual; 251 } 252 253 /* queue the buffer for some later OUT packet */ 254 req->length = buflen; 255 status = usb_ep_queue(ep, req, GFP_ATOMIC); 256 if (status == 0) 257 return; 258 259 /* "should never get here" */ 260 /* FALLTHROUGH */ 261 262 default: 263 ERROR(cdev, "%s loop complete --> %d, %d/%d\n", ep->name, 264 status, req->actual, req->length); 265 /* FALLTHROUGH */ 266 267 /* NOTE: since this driver doesn't maintain an explicit record 268 * of requests it submitted (just maintains qlen count), we 269 * rely on the hardware driver to clean up on disconnect or 270 * endpoint disable. 271 */ 272 case -ECONNABORTED: /* hardware forced ep reset */ 273 case -ECONNRESET: /* request dequeued */ 274 case -ESHUTDOWN: /* disconnect from host */ 275 free_ep_req(ep, req); 276 return; 277 } 278 } 279 280 static void disable_loopback(struct f_loopback *loop) 281 { 282 struct usb_composite_dev *cdev; 283 284 cdev = loop->function.config->cdev; 285 disable_endpoints(cdev, loop->in_ep, loop->out_ep, NULL, NULL); 286 VDBG(cdev, "%s disabled\n", loop->function.name); 287 } 288 289 static inline struct usb_request *lb_alloc_ep_req(struct usb_ep *ep, int len) 290 { 291 return alloc_ep_req(ep, len, buflen); 292 } 293 294 static int enable_endpoint(struct usb_composite_dev *cdev, struct f_loopback *loop, 295 struct usb_ep *ep) 296 { 297 struct usb_request *req; 298 unsigned i; 299 int result; 300 301 /* 302 * one endpoint writes data back IN to the host while another endpoint 303 * just reads OUT packets 304 */ 305 result = config_ep_by_speed(cdev->gadget, &(loop->function), ep); 306 if (result) 307 goto fail0; 308 result = usb_ep_enable(ep); 309 if (result < 0) 310 goto fail0; 311 ep->driver_data = loop; 312 313 /* 314 * allocate a bunch of read buffers and queue them all at once. 315 * we buffer at most 'qlen' transfers; fewer if any need more 316 * than 'buflen' bytes each. 317 */ 318 for (i = 0; i < qlen && result == 0; i++) { 319 req = lb_alloc_ep_req(ep, 0); 320 if (!req) 321 goto fail1; 322 323 req->complete = loopback_complete; 324 result = usb_ep_queue(ep, req, GFP_ATOMIC); 325 if (result) { 326 ERROR(cdev, "%s queue req --> %d\n", 327 ep->name, result); 328 goto fail1; 329 } 330 } 331 332 return 0; 333 334 fail1: 335 usb_ep_disable(ep); 336 337 fail0: 338 return result; 339 } 340 341 static int 342 enable_loopback(struct usb_composite_dev *cdev, struct f_loopback *loop) 343 { 344 int result = 0; 345 346 result = enable_endpoint(cdev, loop, loop->in_ep); 347 if (result) 348 return result; 349 350 result = enable_endpoint(cdev, loop, loop->out_ep); 351 if (result) 352 return result; 353 354 DBG(cdev, "%s enabled\n", loop->function.name); 355 return result; 356 } 357 358 static int loopback_set_alt(struct usb_function *f, 359 unsigned intf, unsigned alt) 360 { 361 struct f_loopback *loop = func_to_loop(f); 362 struct usb_composite_dev *cdev = f->config->cdev; 363 364 /* we know alt is zero */ 365 disable_loopback(loop); 366 return enable_loopback(cdev, loop); 367 } 368 369 static void loopback_disable(struct usb_function *f) 370 { 371 struct f_loopback *loop = func_to_loop(f); 372 373 disable_loopback(loop); 374 } 375 376 static struct usb_function *loopback_alloc(struct usb_function_instance *fi) 377 { 378 struct f_loopback *loop; 379 struct f_lb_opts *lb_opts; 380 381 loop = kzalloc(sizeof *loop, GFP_KERNEL); 382 if (!loop) 383 return ERR_PTR(-ENOMEM); 384 385 lb_opts = container_of(fi, struct f_lb_opts, func_inst); 386 387 mutex_lock(&lb_opts->lock); 388 lb_opts->refcnt++; 389 mutex_unlock(&lb_opts->lock); 390 391 buflen = lb_opts->bulk_buflen; 392 qlen = lb_opts->qlen; 393 if (!qlen) 394 qlen = 32; 395 396 loop->function.name = "loopback"; 397 loop->function.bind = loopback_bind; 398 loop->function.set_alt = loopback_set_alt; 399 loop->function.disable = loopback_disable; 400 loop->function.strings = loopback_strings; 401 402 loop->function.free_func = lb_free_func; 403 404 return &loop->function; 405 } 406 407 static inline struct f_lb_opts *to_f_lb_opts(struct config_item *item) 408 { 409 return container_of(to_config_group(item), struct f_lb_opts, 410 func_inst.group); 411 } 412 413 CONFIGFS_ATTR_STRUCT(f_lb_opts); 414 CONFIGFS_ATTR_OPS(f_lb_opts); 415 416 static void lb_attr_release(struct config_item *item) 417 { 418 struct f_lb_opts *lb_opts = to_f_lb_opts(item); 419 420 usb_put_function_instance(&lb_opts->func_inst); 421 } 422 423 static struct configfs_item_operations lb_item_ops = { 424 .release = lb_attr_release, 425 .show_attribute = f_lb_opts_attr_show, 426 .store_attribute = f_lb_opts_attr_store, 427 }; 428 429 static ssize_t f_lb_opts_qlen_show(struct f_lb_opts *opts, char *page) 430 { 431 int result; 432 433 mutex_lock(&opts->lock); 434 result = sprintf(page, "%d", opts->qlen); 435 mutex_unlock(&opts->lock); 436 437 return result; 438 } 439 440 static ssize_t f_lb_opts_qlen_store(struct f_lb_opts *opts, 441 const char *page, size_t len) 442 { 443 int ret; 444 u32 num; 445 446 mutex_lock(&opts->lock); 447 if (opts->refcnt) { 448 ret = -EBUSY; 449 goto end; 450 } 451 452 ret = kstrtou32(page, 0, &num); 453 if (ret) 454 goto end; 455 456 opts->qlen = num; 457 ret = len; 458 end: 459 mutex_unlock(&opts->lock); 460 return ret; 461 } 462 463 static struct f_lb_opts_attribute f_lb_opts_qlen = 464 __CONFIGFS_ATTR(qlen, S_IRUGO | S_IWUSR, 465 f_lb_opts_qlen_show, 466 f_lb_opts_qlen_store); 467 468 static ssize_t f_lb_opts_bulk_buflen_show(struct f_lb_opts *opts, char *page) 469 { 470 int result; 471 472 mutex_lock(&opts->lock); 473 result = sprintf(page, "%d", opts->bulk_buflen); 474 mutex_unlock(&opts->lock); 475 476 return result; 477 } 478 479 static ssize_t f_lb_opts_bulk_buflen_store(struct f_lb_opts *opts, 480 const char *page, size_t len) 481 { 482 int ret; 483 u32 num; 484 485 mutex_lock(&opts->lock); 486 if (opts->refcnt) { 487 ret = -EBUSY; 488 goto end; 489 } 490 491 ret = kstrtou32(page, 0, &num); 492 if (ret) 493 goto end; 494 495 opts->bulk_buflen = num; 496 ret = len; 497 end: 498 mutex_unlock(&opts->lock); 499 return ret; 500 } 501 502 static struct f_lb_opts_attribute f_lb_opts_bulk_buflen = 503 __CONFIGFS_ATTR(buflen, S_IRUGO | S_IWUSR, 504 f_lb_opts_bulk_buflen_show, 505 f_lb_opts_bulk_buflen_store); 506 507 static struct configfs_attribute *lb_attrs[] = { 508 &f_lb_opts_qlen.attr, 509 &f_lb_opts_bulk_buflen.attr, 510 NULL, 511 }; 512 513 static struct config_item_type lb_func_type = { 514 .ct_item_ops = &lb_item_ops, 515 .ct_attrs = lb_attrs, 516 .ct_owner = THIS_MODULE, 517 }; 518 519 static void lb_free_instance(struct usb_function_instance *fi) 520 { 521 struct f_lb_opts *lb_opts; 522 523 lb_opts = container_of(fi, struct f_lb_opts, func_inst); 524 kfree(lb_opts); 525 } 526 527 static struct usb_function_instance *loopback_alloc_instance(void) 528 { 529 struct f_lb_opts *lb_opts; 530 531 lb_opts = kzalloc(sizeof(*lb_opts), GFP_KERNEL); 532 if (!lb_opts) 533 return ERR_PTR(-ENOMEM); 534 mutex_init(&lb_opts->lock); 535 lb_opts->func_inst.free_func_inst = lb_free_instance; 536 lb_opts->bulk_buflen = GZERO_BULK_BUFLEN; 537 lb_opts->qlen = GZERO_QLEN; 538 539 config_group_init_type_name(&lb_opts->func_inst.group, "", 540 &lb_func_type); 541 542 return &lb_opts->func_inst; 543 } 544 DECLARE_USB_FUNCTION(Loopback, loopback_alloc_instance, loopback_alloc); 545 546 int __init lb_modinit(void) 547 { 548 int ret; 549 550 ret = usb_function_register(&Loopbackusb_func); 551 if (ret) 552 return ret; 553 return ret; 554 } 555 void __exit lb_modexit(void) 556 { 557 usb_function_unregister(&Loopbackusb_func); 558 } 559 560 MODULE_LICENSE("GPL"); 561