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  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 /* #define VERBOSE_DEBUG */
  23
  24 #include <linux/slab.h>
  25 #include <linux/kernel.h>
  26 #include <linux/device.h>
  27
  28 #include "g_zero.h"
  29 #include "gadget_chips.h"
  30
  31
  32 /*
  33  * LOOPBACK FUNCTION ... a testing vehicle for USB peripherals,
  34  *
  35  * This takes messages of various sizes written OUT to a device, and loops
  36  * them back so they can be read IN from it.  It has been used by certain
  37  * test applications.  It supports limited testing of data queueing logic.
  38  *
  39  *
  40  * This is currently packaged as a configuration driver, which can't be
  41  * combined with other functions to make composite devices.  However, it
  42  * can be combined with other independent configurations.
  43  */
  44 struct f_loopback {
  45         struct usb_function     function;
  46
  47         struct usb_ep           *in_ep;
  48         struct usb_ep           *out_ep;
  49 };
  50
  51 static inline struct f_loopback *func_to_loop(struct usb_function *f)
  52 {
  53         return container_of(f, struct f_loopback, function);
  54 }
  55
  56 static unsigned qlen = 32;
  57 module_param(qlen, uint, 0);
  58 MODULE_PARM_DESC(qlenn, "depth of loopback queue");
  59
  60 /*-------------------------------------------------------------------------*/
  61
  62 static struct usb_interface_descriptor loopback_intf = {
  63         .bLength =              sizeof loopback_intf,
  64         .bDescriptorType =      USB_DT_INTERFACE,
  65
  66         .bNumEndpoints =        2,
  67         .bInterfaceClass =      USB_CLASS_VENDOR_SPEC,
  68         /* .iInterface = DYNAMIC */
  69 };
  70
  71 /* full speed support: */
  72
  73 static struct usb_endpoint_descriptor fs_loop_source_desc = {
  74         .bLength =              USB_DT_ENDPOINT_SIZE,
  75         .bDescriptorType =      USB_DT_ENDPOINT,
  76
  77         .bEndpointAddress =     USB_DIR_IN,
  78         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  79 };
  80
  81 static struct usb_endpoint_descriptor fs_loop_sink_desc = {
  82         .bLength =              USB_DT_ENDPOINT_SIZE,
  83         .bDescriptorType =      USB_DT_ENDPOINT,
  84
  85         .bEndpointAddress =     USB_DIR_OUT,
  86         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  87 };
  88
  89 static struct usb_descriptor_header *fs_loopback_descs[] = {
  90         (struct usb_descriptor_header *) &loopback_intf,
  91         (struct usb_descriptor_header *) &fs_loop_sink_desc,
  92         (struct usb_descriptor_header *) &fs_loop_source_desc,
  93         NULL,
  94 };
  95
  96 /* high speed support: */
  97
  98 static struct usb_endpoint_descriptor hs_loop_source_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
 106 static struct usb_endpoint_descriptor hs_loop_sink_desc = {
 107         .bLength =              USB_DT_ENDPOINT_SIZE,
 108         .bDescriptorType =      USB_DT_ENDPOINT,
 109
 110         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 111         .wMaxPacketSize =       cpu_to_le16(512),
 112 };
 113
 114 static struct usb_descriptor_header *hs_loopback_descs[] = {
 115         (struct usb_descriptor_header *) &loopback_intf,
 116         (struct usb_descriptor_header *) &hs_loop_source_desc,
 117         (struct usb_descriptor_header *) &hs_loop_sink_desc,
 118         NULL,
 119 };
 120
 121 /* function-specific strings: */
 122
 123 static struct usb_string strings_loopback[] = {
 124         [0].s = "loop input to output",
 125         {  }                    /* end of list */
 126 };
 127
 128 static struct usb_gadget_strings stringtab_loop = {
 129         .language       = 0x0409,       /* en-us */
 130         .strings        = strings_loopback,
 131 };
 132
 133 static struct usb_gadget_strings *loopback_strings[] = {
 134         &stringtab_loop,
 135         NULL,
 136 };
 137
 138 /*-------------------------------------------------------------------------*/
 139
 140 static int __init
 141 loopback_bind(struct usb_configuration *c, struct usb_function *f)
 142 {
 143         struct usb_composite_dev *cdev = c->cdev;
 144         struct f_loopback       *loop = func_to_loop(f);
 145         int                     id;
 146
 147         /* allocate interface ID(s) */
 148         id = usb_interface_id(c, f);
 149         if (id < 0)
 150                 return id;
 151         loopback_intf.bInterfaceNumber = id;
 152
 153         /* allocate endpoints */
 154
 155         loop->in_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_source_desc);
 156         if (!loop->in_ep) {
 157 autoconf_fail:
 158                 ERROR(cdev, "%s: can't autoconfigure on %s\n",
 159                         f->name, cdev->gadget->name);
 160                 return -ENODEV;
 161         }
 162         loop->in_ep->driver_data = cdev;        /* claim */
 163
 164         loop->out_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_sink_desc);
 165         if (!loop->out_ep)
 166                 goto autoconf_fail;
 167         loop->out_ep->driver_data = cdev;       /* claim */
 168
 169         /* support high speed hardware */
 170         if (gadget_is_dualspeed(c->cdev->gadget)) {
 171                 hs_loop_source_desc.bEndpointAddress =
 172                                 fs_loop_source_desc.bEndpointAddress;
 173                 hs_loop_sink_desc.bEndpointAddress =
 174                                 fs_loop_sink_desc.bEndpointAddress;
 175                 f->hs_descriptors = hs_loopback_descs;
 176         }
 177
 178         DBG(cdev, "%s speed %s: IN/%s, OUT/%s\n",
 179                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 180                         f->name, loop->in_ep->name, loop->out_ep->name);
 181         return 0;
 182 }
 183
 184 static void
 185 loopback_unbind(struct usb_configuration *c, struct usb_function *f)
 186 {
 187         kfree(func_to_loop(f));
 188 }
 189
 190 static void loopback_complete(struct usb_ep *ep, struct usb_request *req)
 191 {
 192         struct f_loopback       *loop = ep->driver_data;
 193         struct usb_composite_dev *cdev = loop->function.config->cdev;
 194         int                     status = req->status;
 195
 196         switch (status) {
 197
 198         case 0:                         /* normal completion? */
 199                 if (ep == loop->out_ep) {
 200                         /* loop this OUT packet back IN to the host */
 201                         req->zero = (req->actual < req->length);
 202                         req->length = req->actual;
 203                         status = usb_ep_queue(loop->in_ep, req, GFP_ATOMIC);
 204                         if (status == 0)
 205                                 return;
 206
 207                         /* "should never get here" */
 208                         ERROR(cdev, "can't loop %s to %s: %d\n",
 209                                 ep->name, loop->in_ep->name,
 210                                 status);
 211                 }
 212
 213                 /* queue the buffer for some later OUT packet */
 214                 req->length = buflen;
 215                 status = usb_ep_queue(loop->out_ep, req, GFP_ATOMIC);
 216                 if (status == 0)
 217                         return;
 218
 219                 /* "should never get here" */
 220                 /* FALLTHROUGH */
 221
 222         default:
 223                 ERROR(cdev, "%s loop complete --> %d, %d/%d\n", ep->name,
 224                                 status, req->actual, req->length);
 225                 /* FALLTHROUGH */
 226
 227         /* NOTE:  since this driver doesn't maintain an explicit record
 228          * of requests it submitted (just maintains qlen count), we
 229          * rely on the hardware driver to clean up on disconnect or
 230          * endpoint disable.
 231          */
 232         case -ECONNABORTED:             /* hardware forced ep reset */
 233         case -ECONNRESET:               /* request dequeued */
 234         case -ESHUTDOWN:                /* disconnect from host */
 235                 free_ep_req(ep, req);
 236                 return;
 237         }
 238 }
 239
 240 static void disable_loopback(struct f_loopback *loop)
 241 {
 242         struct usb_composite_dev        *cdev;
 243
 244         cdev = loop->function.config->cdev;
 245         disable_endpoints(cdev, loop->in_ep, loop->out_ep);
 246         VDBG(cdev, "%s disabled\n", loop->function.name);
 247 }
 248
 249 static int
 250 enable_loopback(struct usb_composite_dev *cdev, struct f_loopback *loop)
 251 {
 252         int                                     result = 0;
 253         const struct usb_endpoint_descriptor    *src, *sink;
 254         struct usb_ep                           *ep;
 255         struct usb_request                      *req;
 256         unsigned                                i;
 257
 258         src = ep_choose(cdev->gadget,
 259                         &hs_loop_source_desc, &fs_loop_source_desc);
 260         sink = ep_choose(cdev->gadget,
 261                         &hs_loop_sink_desc, &fs_loop_sink_desc);
 262
 263         /* one endpoint writes data back IN to the host */
 264         ep = loop->in_ep;
 265         result = usb_ep_enable(ep, src);
 266         if (result < 0)
 267                 return result;
 268         ep->driver_data = loop;
 269
 270         /* one endpoint just reads OUT packets */
 271         ep = loop->out_ep;
 272         result = usb_ep_enable(ep, sink);
 273         if (result < 0) {
 274 fail0:
 275                 ep = loop->in_ep;
 276                 usb_ep_disable(ep);
 277                 ep->driver_data = NULL;
 278                 return result;
 279         }
 280         ep->driver_data = loop;
 281
 282         /* allocate a bunch of read buffers and queue them all at once.
 283          * we buffer at most 'qlen' transfers; fewer if any need more
 284          * than 'buflen' bytes each.
 285          */
 286         for (i = 0; i < qlen && result == 0; i++) {
 287                 req = alloc_ep_req(ep);
 288                 if (req) {
 289                         req->complete = loopback_complete;
 290                         result = usb_ep_queue(ep, req, GFP_ATOMIC);
 291                         if (result)
 292                                 ERROR(cdev, "%s queue req --> %d\n",
 293                                                 ep->name, result);
 294                 } else {
 295                         usb_ep_disable(ep);
 296                         ep->driver_data = NULL;
 297                         result = -ENOMEM;
 298                         goto fail0;
 299                 }
 300         }
 301
 302         DBG(cdev, "%s enabled\n", loop->function.name);
 303         return result;
 304 }
 305
 306 static int loopback_set_alt(struct usb_function *f,
 307                 unsigned intf, unsigned alt)
 308 {
 309         struct f_loopback       *loop = func_to_loop(f);
 310         struct usb_composite_dev *cdev = f->config->cdev;
 311
 312         /* we know alt is zero */
 313         if (loop->in_ep->driver_data)
 314                 disable_loopback(loop);
 315         return enable_loopback(cdev, loop);
 316 }
 317
 318 static void loopback_disable(struct usb_function *f)
 319 {
 320         struct f_loopback       *loop = func_to_loop(f);
 321
 322         disable_loopback(loop);
 323 }
 324
 325 /*-------------------------------------------------------------------------*/
 326
 327 static int __init loopback_bind_config(struct usb_configuration *c)
 328 {
 329         struct f_loopback       *loop;
 330         int                     status;
 331
 332         loop = kzalloc(sizeof *loop, GFP_KERNEL);
 333         if (!loop)
 334                 return -ENOMEM;
 335
 336         loop->function.name = "loopback";
 337         loop->function.descriptors = fs_loopback_descs;
 338         loop->function.bind = loopback_bind;
 339         loop->function.unbind = loopback_unbind;
 340         loop->function.set_alt = loopback_set_alt;
 341         loop->function.disable = loopback_disable;
 342
 343         status = usb_add_function(c, &loop->function);
 344         if (status)
 345                 kfree(loop);
 346         return status;
 347 }
 348
 349 static struct usb_configuration loopback_driver = {
 350         .label          = "loopback",
 351         .strings        = loopback_strings,
 352         .bConfigurationValue = 2,
 353         .bmAttributes   = USB_CONFIG_ATT_SELFPOWER,
 354         /* .iConfiguration = DYNAMIC */
 355 };
 356
 357 /**
 358  * loopback_add - add a loopback testing configuration to a device
 359  * @cdev: the device to support the loopback configuration
 360  */
 361 int __init loopback_add(struct usb_composite_dev *cdev, bool autoresume)
 362 {
 363         int id;
 364
 365         /* allocate string ID(s) */
 366         id = usb_string_id(cdev);
 367         if (id < 0)
 368                 return id;
 369         strings_loopback[0].id = id;
 370
 371         loopback_intf.iInterface = id;
 372         loopback_driver.iConfiguration = id;
 373
 374         /* support autoresume for remote wakeup testing */
 375         if (autoresume)
 376                 sourcesink_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
 377
 378         /* support OTG systems */
 379         if (gadget_is_otg(cdev->gadget)) {
 380                 loopback_driver.descriptors = otg_desc;
 381                 loopback_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
 382         }
 383
 384         return usb_add_config(cdev, &loopback_driver, loopback_bind_config);
 385 }