drivers/usb/gadget/function/f_loopback.c

   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\n", 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\n", 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");