drivers/usb/gadget/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
  24 /*
  25  * LOOPBACK FUNCTION ... a testing vehicle for USB peripherals,
  26  *
  27  * This takes messages of various sizes written OUT to a device, and loops
  28  * them back so they can be read IN from it.  It has been used by certain
  29  * test applications.  It supports limited testing of data queueing logic.
  30  *
  31  *
  32  * This is currently packaged as a configuration driver, which can't be
  33  * combined with other functions to make composite devices.  However, it
  34  * can be combined with other independent configurations.
  35  */
  36 struct f_loopback {
  37         struct usb_function     function;
  38
  39         struct usb_ep           *in_ep;
  40         struct usb_ep           *out_ep;
  41 };
  42
  43 static inline struct f_loopback *func_to_loop(struct usb_function *f)
  44 {
  45         return container_of(f, struct f_loopback, function);
  46 }
  47
  48 static unsigned qlen;
  49 static unsigned buflen;
  50
  51 /*-------------------------------------------------------------------------*/
  52
  53 static struct usb_interface_descriptor loopback_intf = {
  54         .bLength =              sizeof loopback_intf,
  55         .bDescriptorType =      USB_DT_INTERFACE,
  56
  57         .bNumEndpoints =        2,
  58         .bInterfaceClass =      USB_CLASS_VENDOR_SPEC,
  59         /* .iInterface = DYNAMIC */
  60 };
  61
  62 /* full speed support: */
  63
  64 static struct usb_endpoint_descriptor fs_loop_source_desc = {
  65         .bLength =              USB_DT_ENDPOINT_SIZE,
  66         .bDescriptorType =      USB_DT_ENDPOINT,
  67
  68         .bEndpointAddress =     USB_DIR_IN,
  69         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  70 };
  71
  72 static struct usb_endpoint_descriptor fs_loop_sink_desc = {
  73         .bLength =              USB_DT_ENDPOINT_SIZE,
  74         .bDescriptorType =      USB_DT_ENDPOINT,
  75
  76         .bEndpointAddress =     USB_DIR_OUT,
  77         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  78 };
  79
  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,
  84         NULL,
  85 };
  86
  87 /* high speed support: */
  88
  89 static struct usb_endpoint_descriptor hs_loop_source_desc = {
  90         .bLength =              USB_DT_ENDPOINT_SIZE,
  91         .bDescriptorType =      USB_DT_ENDPOINT,
  92
  93         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  94         .wMaxPacketSize =       cpu_to_le16(512),
  95 };
  96
  97 static struct usb_endpoint_descriptor hs_loop_sink_desc = {
  98         .bLength =              USB_DT_ENDPOINT_SIZE,
  99         .bDescriptorType =      USB_DT_ENDPOINT,
 100
 101         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 102         .wMaxPacketSize =       cpu_to_le16(512),
 103 };
 104
 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,
 109         NULL,
 110 };
 111
 112 /* super speed support: */
 113
 114 static struct usb_endpoint_descriptor ss_loop_source_desc = {
 115         .bLength =              USB_DT_ENDPOINT_SIZE,
 116         .bDescriptorType =      USB_DT_ENDPOINT,
 117
 118         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 119         .wMaxPacketSize =       cpu_to_le16(1024),
 120 };
 121
 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,
 125         .bMaxBurst =            0,
 126         .bmAttributes =         0,
 127         .wBytesPerInterval =    0,
 128 };
 129
 130 static struct usb_endpoint_descriptor ss_loop_sink_desc = {
 131         .bLength =              USB_DT_ENDPOINT_SIZE,
 132         .bDescriptorType =      USB_DT_ENDPOINT,
 133
 134         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 135         .wMaxPacketSize =       cpu_to_le16(1024),
 136 };
 137
 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,
 141         .bMaxBurst =            0,
 142         .bmAttributes =         0,
 143         .wBytesPerInterval =    0,
 144 };
 145
 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,
 152         NULL,
 153 };
 154
 155 /* function-specific strings: */
 156
 157 static struct usb_string strings_loopback[] = {
 158         [0].s = "loop input to output",
 159         {  }                    /* end of list */
 160 };
 161
 162 static struct usb_gadget_strings stringtab_loop = {
 163         .language       = 0x0409,       /* en-us */
 164         .strings        = strings_loopback,
 165 };
 166
 167 static struct usb_gadget_strings *loopback_strings[] = {
 168         &stringtab_loop,
 169         NULL,
 170 };
 171
 172 /*-------------------------------------------------------------------------*/
 173
 174 static int loopback_bind(struct usb_configuration *c, struct usb_function *f)
 175 {
 176         struct usb_composite_dev *cdev = c->cdev;
 177         struct f_loopback       *loop = func_to_loop(f);
 178         int                     id;
 179         int ret;
 180
 181         /* allocate interface ID(s) */
 182         id = usb_interface_id(c, f);
 183         if (id < 0)
 184                 return id;
 185         loopback_intf.bInterfaceNumber = id;
 186
 187         id = usb_string_id(cdev);
 188         if (id < 0)
 189                 return id;
 190         strings_loopback[0].id = id;
 191         loopback_intf.iInterface = id;
 192
 193         /* allocate endpoints */
 194
 195         loop->in_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_source_desc);
 196         if (!loop->in_ep) {
 197 autoconf_fail:
 198                 ERROR(cdev, "%s: can't autoconfigure on %s\n",
 199                         f->name, cdev->gadget->name);
 200                 return -ENODEV;
 201         }
 202         loop->in_ep->driver_data = cdev;        /* claim */
 203
 204         loop->out_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_sink_desc);
 205         if (!loop->out_ep)
 206                 goto autoconf_fail;
 207         loop->out_ep->driver_data = cdev;       /* claim */
 208
 209         /* support high speed hardware */
 210         hs_loop_source_desc.bEndpointAddress =
 211                 fs_loop_source_desc.bEndpointAddress;
 212         hs_loop_sink_desc.bEndpointAddress = fs_loop_sink_desc.bEndpointAddress;
 213
 214         /* support super speed hardware */
 215         ss_loop_source_desc.bEndpointAddress =
 216                 fs_loop_source_desc.bEndpointAddress;
 217         ss_loop_sink_desc.bEndpointAddress = fs_loop_sink_desc.bEndpointAddress;
 218
 219         ret = usb_assign_descriptors(f, fs_loopback_descs, hs_loopback_descs,
 220                         ss_loopback_descs);
 221         if (ret)
 222                 return ret;
 223
 224         DBG(cdev, "%s speed %s: IN/%s, OUT/%s\n",
 225             (gadget_is_superspeed(c->cdev->gadget) ? "super" :
 226              (gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full")),
 227                         f->name, loop->in_ep->name, loop->out_ep->name);
 228         return 0;
 229 }
 230
 231 static void lb_free_func(struct usb_function *f)
 232 {
 233         usb_free_all_descriptors(f);
 234         kfree(func_to_loop(f));
 235 }
 236
 237 static void loopback_complete(struct usb_ep *ep, struct usb_request *req)
 238 {
 239         struct f_loopback       *loop = ep->driver_data;
 240         struct usb_composite_dev *cdev = loop->function.config->cdev;
 241         int                     status = req->status;
 242
 243         switch (status) {
 244
 245         case 0:                         /* normal completion? */
 246                 if (ep == loop->out_ep) {
 247                         /* loop this OUT packet back IN to the host */
 248                         req->zero = (req->actual < req->length);
 249                         req->length = req->actual;
 250                         status = usb_ep_queue(loop->in_ep, req, GFP_ATOMIC);
 251                         if (status == 0)
 252                                 return;
 253
 254                         /* "should never get here" */
 255                         ERROR(cdev, "can't loop %s to %s: %d\n",
 256                                 ep->name, loop->in_ep->name,
 257                                 status);
 258                 }
 259
 260                 /* queue the buffer for some later OUT packet */
 261                 req->length = buflen;
 262                 status = usb_ep_queue(loop->out_ep, req, GFP_ATOMIC);
 263                 if (status == 0)
 264                         return;
 265
 266                 /* "should never get here" */
 267                 /* FALLTHROUGH */
 268
 269         default:
 270                 ERROR(cdev, "%s loop complete --> %d, %d/%d\n", ep->name,
 271                                 status, req->actual, req->length);
 272                 /* FALLTHROUGH */
 273
 274         /* NOTE:  since this driver doesn't maintain an explicit record
 275          * of requests it submitted (just maintains qlen count), we
 276          * rely on the hardware driver to clean up on disconnect or
 277          * endpoint disable.
 278          */
 279         case -ECONNABORTED:             /* hardware forced ep reset */
 280         case -ECONNRESET:               /* request dequeued */
 281         case -ESHUTDOWN:                /* disconnect from host */
 282                 free_ep_req(ep, req);
 283                 return;
 284         }
 285 }
 286
 287 static void disable_loopback(struct f_loopback *loop)
 288 {
 289         struct usb_composite_dev        *cdev;
 290
 291         cdev = loop->function.config->cdev;
 292         disable_endpoints(cdev, loop->in_ep, loop->out_ep, NULL, NULL);
 293         VDBG(cdev, "%s disabled\n", loop->function.name);
 294 }
 295
 296 static int
 297 enable_loopback(struct usb_composite_dev *cdev, struct f_loopback *loop)
 298 {
 299         int                                     result = 0;
 300         struct usb_ep                           *ep;
 301         struct usb_request                      *req;
 302         unsigned                                i;
 303
 304         /* one endpoint writes data back IN to the host */
 305         ep = loop->in_ep;
 306         result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
 307         if (result)
 308                 return result;
 309         result = usb_ep_enable(ep);
 310         if (result < 0)
 311                 return result;
 312         ep->driver_data = loop;
 313
 314         /* one endpoint just reads OUT packets */
 315         ep = loop->out_ep;
 316         result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
 317         if (result)
 318                 goto fail0;
 319
 320         result = usb_ep_enable(ep);
 321         if (result < 0) {
 322 fail0:
 323                 ep = loop->in_ep;
 324                 usb_ep_disable(ep);
 325                 ep->driver_data = NULL;
 326                 return result;
 327         }
 328         ep->driver_data = loop;
 329
 330         /* allocate a bunch of read buffers and queue them all at once.
 331          * we buffer at most 'qlen' transfers; fewer if any need more
 332          * than 'buflen' bytes each.
 333          */
 334         for (i = 0; i < qlen && result == 0; i++) {
 335                 req = alloc_ep_req(ep, 0);
 336                 if (req) {
 337                         req->complete = loopback_complete;
 338                         result = usb_ep_queue(ep, req, GFP_ATOMIC);
 339                         if (result)
 340                                 ERROR(cdev, "%s queue req --> %d\n",
 341                                                 ep->name, result);
 342                 } else {
 343                         usb_ep_disable(ep);
 344                         ep->driver_data = NULL;
 345                         result = -ENOMEM;
 346                         goto fail0;
 347                 }
 348         }
 349
 350         DBG(cdev, "%s enabled\n", loop->function.name);
 351         return result;
 352 }
 353
 354 static int loopback_set_alt(struct usb_function *f,
 355                 unsigned intf, unsigned alt)
 356 {
 357         struct f_loopback       *loop = func_to_loop(f);
 358         struct usb_composite_dev *cdev = f->config->cdev;
 359
 360         /* we know alt is zero */
 361         if (loop->in_ep->driver_data)
 362                 disable_loopback(loop);
 363         return enable_loopback(cdev, loop);
 364 }
 365
 366 static void loopback_disable(struct usb_function *f)
 367 {
 368         struct f_loopback       *loop = func_to_loop(f);
 369
 370         disable_loopback(loop);
 371 }
 372
 373 static struct usb_function *loopback_alloc(struct usb_function_instance *fi)
 374 {
 375         struct f_loopback       *loop;
 376         struct f_lb_opts        *lb_opts;
 377
 378         loop = kzalloc(sizeof *loop, GFP_KERNEL);
 379         if (!loop)
 380                 return ERR_PTR(-ENOMEM);
 381
 382         lb_opts = container_of(fi, struct f_lb_opts, func_inst);
 383         buflen = lb_opts->bulk_buflen;
 384         qlen = lb_opts->qlen;
 385         if (!qlen)
 386                 qlen = 32;
 387
 388         loop->function.name = "loopback";
 389         loop->function.bind = loopback_bind;
 390         loop->function.set_alt = loopback_set_alt;
 391         loop->function.disable = loopback_disable;
 392         loop->function.strings = loopback_strings;
 393
 394         loop->function.free_func = lb_free_func;
 395
 396         return &loop->function;
 397 }
 398
 399 static void lb_free_instance(struct usb_function_instance *fi)
 400 {
 401         struct f_lb_opts *lb_opts;
 402
 403         lb_opts = container_of(fi, struct f_lb_opts, func_inst);
 404         kfree(lb_opts);
 405 }
 406
 407 static struct usb_function_instance *loopback_alloc_instance(void)
 408 {
 409         struct f_lb_opts *lb_opts;
 410
 411         lb_opts = kzalloc(sizeof(*lb_opts), GFP_KERNEL);
 412         if (!lb_opts)
 413                 return ERR_PTR(-ENOMEM);
 414         lb_opts->func_inst.free_func_inst = lb_free_instance;
 415         return  &lb_opts->func_inst;
 416 }
 417 DECLARE_USB_FUNCTION(Loopback, loopback_alloc_instance, loopback_alloc);
 418
 419 int __init lb_modinit(void)
 420 {
 421         int ret;
 422
 423         ret = usb_function_register(&Loopbackusb_func);
 424         if (ret)
 425                 return ret;
 426         return ret;
 427 }
 428 void __exit lb_modexit(void)
 429 {
 430         usb_function_unregister(&Loopbackusb_func);
 431 }
 432
 433 MODULE_LICENSE("GPL");