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         unsigned                qlen;
  39         unsigned                buflen;
  40 };
  41
  42 static inline struct f_loopback *func_to_loop(struct usb_function *f)
  43 {
  44         return container_of(f, struct f_loopback, function);
  45 }
  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 = loop->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         struct f_loopback       *loop = ep->driver_data;
 292
 293         return alloc_ep_req(ep, len, loop->buflen);
 294 }
 295
 296 static int enable_endpoint(struct usb_composite_dev *cdev, struct f_loopback *loop,
 297                 struct usb_ep *ep)
 298 {
 299         struct usb_request                      *req;
 300         unsigned                                i;
 301         int                                     result;
 302
 303         /*
 304          * one endpoint writes data back IN to the host while another endpoint
 305          * just reads OUT packets
 306          */
 307         result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
 308         if (result)
 309                 goto fail0;
 310         result = usb_ep_enable(ep);
 311         if (result < 0)
 312                 goto fail0;
 313         ep->driver_data = loop;
 314
 315         /*
 316          * allocate a bunch of read buffers and queue them all at once.
 317          * we buffer at most 'qlen' transfers; fewer if any need more
 318          * than 'buflen' bytes each.
 319          */
 320         for (i = 0; i < loop->qlen && result == 0; i++) {
 321                 req = lb_alloc_ep_req(ep, 0);
 322                 if (!req)
 323                         goto fail1;
 324
 325                 req->complete = loopback_complete;
 326                 result = usb_ep_queue(ep, req, GFP_ATOMIC);
 327                 if (result) {
 328                         ERROR(cdev, "%s queue req --> %d\n",
 329                                         ep->name, result);
 330                         goto fail1;
 331                 }
 332         }
 333
 334         return 0;
 335
 336 fail1:
 337         usb_ep_disable(ep);
 338
 339 fail0:
 340         return result;
 341 }
 342
 343 static int
 344 enable_loopback(struct usb_composite_dev *cdev, struct f_loopback *loop)
 345 {
 346         int                                     result = 0;
 347
 348         result = enable_endpoint(cdev, loop, loop->in_ep);
 349         if (result)
 350                 return result;
 351
 352         result = enable_endpoint(cdev, loop, loop->out_ep);
 353         if (result)
 354                 return result;
 355
 356         DBG(cdev, "%s enabled\n", loop->function.name);
 357         return result;
 358 }
 359
 360 static int loopback_set_alt(struct usb_function *f,
 361                 unsigned intf, unsigned alt)
 362 {
 363         struct f_loopback       *loop = func_to_loop(f);
 364         struct usb_composite_dev *cdev = f->config->cdev;
 365
 366         /* we know alt is zero */
 367         disable_loopback(loop);
 368         return enable_loopback(cdev, loop);
 369 }
 370
 371 static void loopback_disable(struct usb_function *f)
 372 {
 373         struct f_loopback       *loop = func_to_loop(f);
 374
 375         disable_loopback(loop);
 376 }
 377
 378 static struct usb_function *loopback_alloc(struct usb_function_instance *fi)
 379 {
 380         struct f_loopback       *loop;
 381         struct f_lb_opts        *lb_opts;
 382
 383         loop = kzalloc(sizeof *loop, GFP_KERNEL);
 384         if (!loop)
 385                 return ERR_PTR(-ENOMEM);
 386
 387         lb_opts = container_of(fi, struct f_lb_opts, func_inst);
 388
 389         mutex_lock(&lb_opts->lock);
 390         lb_opts->refcnt++;
 391         mutex_unlock(&lb_opts->lock);
 392
 393         loop->buflen = lb_opts->bulk_buflen;
 394         loop->qlen = lb_opts->qlen;
 395         if (!loop->qlen)
 396                 loop->qlen = 32;
 397
 398         loop->function.name = "loopback";
 399         loop->function.bind = loopback_bind;
 400         loop->function.set_alt = loopback_set_alt;
 401         loop->function.disable = loopback_disable;
 402         loop->function.strings = loopback_strings;
 403
 404         loop->function.free_func = lb_free_func;
 405
 406         return &loop->function;
 407 }
 408
 409 static inline struct f_lb_opts *to_f_lb_opts(struct config_item *item)
 410 {
 411         return container_of(to_config_group(item), struct f_lb_opts,
 412                             func_inst.group);
 413 }
 414
 415 CONFIGFS_ATTR_STRUCT(f_lb_opts);
 416 CONFIGFS_ATTR_OPS(f_lb_opts);
 417
 418 static void lb_attr_release(struct config_item *item)
 419 {
 420         struct f_lb_opts *lb_opts = to_f_lb_opts(item);
 421
 422         usb_put_function_instance(&lb_opts->func_inst);
 423 }
 424
 425 static struct configfs_item_operations lb_item_ops = {
 426         .release                = lb_attr_release,
 427         .show_attribute         = f_lb_opts_attr_show,
 428         .store_attribute        = f_lb_opts_attr_store,
 429 };
 430
 431 static ssize_t f_lb_opts_qlen_show(struct f_lb_opts *opts, char *page)
 432 {
 433         int result;
 434
 435         mutex_lock(&opts->lock);
 436         result = sprintf(page, "%d\n", opts->qlen);
 437         mutex_unlock(&opts->lock);
 438
 439         return result;
 440 }
 441
 442 static ssize_t f_lb_opts_qlen_store(struct f_lb_opts *opts,
 443                                     const char *page, size_t len)
 444 {
 445         int ret;
 446         u32 num;
 447
 448         mutex_lock(&opts->lock);
 449         if (opts->refcnt) {
 450                 ret = -EBUSY;
 451                 goto end;
 452         }
 453
 454         ret = kstrtou32(page, 0, &num);
 455         if (ret)
 456                 goto end;
 457
 458         opts->qlen = num;
 459         ret = len;
 460 end:
 461         mutex_unlock(&opts->lock);
 462         return ret;
 463 }
 464
 465 static struct f_lb_opts_attribute f_lb_opts_qlen =
 466         __CONFIGFS_ATTR(qlen, S_IRUGO | S_IWUSR,
 467                         f_lb_opts_qlen_show,
 468                         f_lb_opts_qlen_store);
 469
 470 static ssize_t f_lb_opts_bulk_buflen_show(struct f_lb_opts *opts, char *page)
 471 {
 472         int result;
 473
 474         mutex_lock(&opts->lock);
 475         result = sprintf(page, "%d\n", opts->bulk_buflen);
 476         mutex_unlock(&opts->lock);
 477
 478         return result;
 479 }
 480
 481 static ssize_t f_lb_opts_bulk_buflen_store(struct f_lb_opts *opts,
 482                                     const char *page, size_t len)
 483 {
 484         int ret;
 485         u32 num;
 486
 487         mutex_lock(&opts->lock);
 488         if (opts->refcnt) {
 489                 ret = -EBUSY;
 490                 goto end;
 491         }
 492
 493         ret = kstrtou32(page, 0, &num);
 494         if (ret)
 495                 goto end;
 496
 497         opts->bulk_buflen = num;
 498         ret = len;
 499 end:
 500         mutex_unlock(&opts->lock);
 501         return ret;
 502 }
 503
 504 static struct f_lb_opts_attribute f_lb_opts_bulk_buflen =
 505         __CONFIGFS_ATTR(buflen, S_IRUGO | S_IWUSR,
 506                         f_lb_opts_bulk_buflen_show,
 507                         f_lb_opts_bulk_buflen_store);
 508
 509 static struct configfs_attribute *lb_attrs[] = {
 510         &f_lb_opts_qlen.attr,
 511         &f_lb_opts_bulk_buflen.attr,
 512         NULL,
 513 };
 514
 515 static struct config_item_type lb_func_type = {
 516         .ct_item_ops    = &lb_item_ops,
 517         .ct_attrs       = lb_attrs,
 518         .ct_owner       = THIS_MODULE,
 519 };
 520
 521 static void lb_free_instance(struct usb_function_instance *fi)
 522 {
 523         struct f_lb_opts *lb_opts;
 524
 525         lb_opts = container_of(fi, struct f_lb_opts, func_inst);
 526         kfree(lb_opts);
 527 }
 528
 529 static struct usb_function_instance *loopback_alloc_instance(void)
 530 {
 531         struct f_lb_opts *lb_opts;
 532
 533         lb_opts = kzalloc(sizeof(*lb_opts), GFP_KERNEL);
 534         if (!lb_opts)
 535                 return ERR_PTR(-ENOMEM);
 536         mutex_init(&lb_opts->lock);
 537         lb_opts->func_inst.free_func_inst = lb_free_instance;
 538         lb_opts->bulk_buflen = GZERO_BULK_BUFLEN;
 539         lb_opts->qlen = GZERO_QLEN;
 540
 541         config_group_init_type_name(&lb_opts->func_inst.group, "",
 542                                     &lb_func_type);
 543
 544         return  &lb_opts->func_inst;
 545 }
 546 DECLARE_USB_FUNCTION(Loopback, loopback_alloc_instance, loopback_alloc);
 547
 548 int __init lb_modinit(void)
 549 {
 550         int ret;
 551
 552         ret = usb_function_register(&Loopbackusb_func);
 553         if (ret)
 554                 return ret;
 555         return ret;
 556 }
 557 void __exit lb_modexit(void)
 558 {
 559         usb_function_unregister(&Loopbackusb_func);
 560 }
 561
 562 MODULE_LICENSE("GPL");