drivers/usb/gadget/composite.c

   1 /*
   2  * composite.c - infrastructure for Composite USB Gadgets
   3  *
   4  * Copyright (C) 2006-2008 David Brownell
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 /* #define VERBOSE_DEBUG */
  22
  23 #include <linux/kallsyms.h>
  24 #include <linux/kernel.h>
  25 #include <linux/slab.h>
  26 #include <linux/device.h>
  27 #include <linux/utsname.h>
  28
  29 #include <linux/usb/composite.h>
  30
  31
  32 /*
  33  * The code in this file is utility code, used to build a gadget driver
  34  * from one or more "function" drivers, one or more "configuration"
  35  * objects, and a "usb_composite_driver" by gluing them together along
  36  * with the relevant device-wide data.
  37  */
  38
  39 /* big enough to hold our biggest descriptor */
  40 #define USB_BUFSIZ      1024
  41
  42 static struct usb_composite_driver *composite;
  43 static int (*composite_gadget_bind)(struct usb_composite_dev *cdev);
  44
  45 /* Some systems will need runtime overrides for the  product identifiers
  46  * published in the device descriptor, either numbers or strings or both.
  47  * String parameters are in UTF-8 (superset of ASCII's 7 bit characters).
  48  */
  49
  50 static ushort idVendor;
  51 module_param(idVendor, ushort, 0);
  52 MODULE_PARM_DESC(idVendor, "USB Vendor ID");
  53
  54 static ushort idProduct;
  55 module_param(idProduct, ushort, 0);
  56 MODULE_PARM_DESC(idProduct, "USB Product ID");
  57
  58 static ushort bcdDevice;
  59 module_param(bcdDevice, ushort, 0);
  60 MODULE_PARM_DESC(bcdDevice, "USB Device version (BCD)");
  61
  62 static char *iManufacturer;
  63 module_param(iManufacturer, charp, 0);
  64 MODULE_PARM_DESC(iManufacturer, "USB Manufacturer string");
  65
  66 static char *iProduct;
  67 module_param(iProduct, charp, 0);
  68 MODULE_PARM_DESC(iProduct, "USB Product string");
  69
  70 static char *iSerialNumber;
  71 module_param(iSerialNumber, charp, 0);
  72 MODULE_PARM_DESC(iSerialNumber, "SerialNumber string");
  73
  74 static char composite_manufacturer[50];
  75 static int gadget_connected = 0;
  76 /*-------------------------------------------------------------------------*/
  77
  78 /**
  79  * usb_add_function() - add a function to a configuration
  80  * @config: the configuration
  81  * @function: the function being added
  82  * Context: single threaded during gadget setup
  83  *
  84  * After initialization, each configuration must have one or more
  85  * functions added to it.  Adding a function involves calling its @bind()
  86  * method to allocate resources such as interface and string identifiers
  87  * and endpoints.
  88  *
  89  * This function returns the value of the function's bind(), which is
  90  * zero for success else a negative errno value.
  91  */
  92 int usb_add_function(struct usb_configuration *config,
  93                 struct usb_function *function)
  94 {
  95         int     value = -EINVAL;
  96
  97         DBG(config->cdev, "adding '%s'/%p to config '%s'/%p\n",
  98                         function->name, function,
  99                         config->label, config);
 100
 101         if (!function->set_alt || !function->disable)
 102                 goto done;
 103
 104         function->config = config;
 105         list_add_tail(&function->list, &config->functions);
 106
 107         /* REVISIT *require* function->bind? */
 108         if (function->bind) {
 109                 value = function->bind(config, function);
 110                 if (value < 0) {
 111                         list_del(&function->list);
 112                         function->config = NULL;
 113                 }
 114         } else
 115                 value = 0;
 116
 117         /* We allow configurations that don't work at both speeds.
 118          * If we run into a lowspeed Linux system, treat it the same
 119          * as full speed ... it's the function drivers that will need
 120          * to avoid bulk and ISO transfers.
 121          */
 122         if (!config->fullspeed && function->descriptors)
 123                 config->fullspeed = true;
 124         if (!config->highspeed && function->hs_descriptors)
 125                 config->highspeed = true;
 126
 127 done:
 128         if (value)
 129                 DBG(config->cdev, "adding '%s'/%p --> %d\n",
 130                                 function->name, function, value);
 131         return value;
 132 }
 133
 134 /**
 135  * usb_function_deactivate - prevent function and gadget enumeration
 136  * @function: the function that isn't yet ready to respond
 137  *
 138  * Blocks response of the gadget driver to host enumeration by
 139  * preventing the data line pullup from being activated.  This is
 140  * normally called during @bind() processing to change from the
 141  * initial "ready to respond" state, or when a required resource
 142  * becomes available.
 143  *
 144  * For example, drivers that serve as a passthrough to a userspace
 145  * daemon can block enumeration unless that daemon (such as an OBEX,
 146  * MTP, or print server) is ready to handle host requests.
 147  *
 148  * Not all systems support software control of their USB peripheral
 149  * data pullups.
 150  *
 151  * Returns zero on success, else negative errno.
 152  */
 153 int usb_function_deactivate(struct usb_function *function)
 154 {
 155         struct usb_composite_dev        *cdev = function->config->cdev;
 156         unsigned long                   flags;
 157         int                             status = 0;
 158
 159         spin_lock_irqsave(&cdev->lock, flags);
 160
 161         if (cdev->deactivations == 0)
 162                 status = usb_gadget_disconnect(cdev->gadget);
 163         if (status == 0)
 164                 cdev->deactivations++;
 165
 166         spin_unlock_irqrestore(&cdev->lock, flags);
 167         return status;
 168 }
 169
 170 /**
 171  * usb_function_activate - allow function and gadget enumeration
 172  * @function: function on which usb_function_activate() was called
 173  *
 174  * Reverses effect of usb_function_deactivate().  If no more functions
 175  * are delaying their activation, the gadget driver will respond to
 176  * host enumeration procedures.
 177  *
 178  * Returns zero on success, else negative errno.
 179  */
 180 int usb_function_activate(struct usb_function *function)
 181 {
 182         struct usb_composite_dev        *cdev = function->config->cdev;
 183         int                             status = 0;
 184
 185         spin_lock(&cdev->lock);
 186
 187         if (WARN_ON(cdev->deactivations == 0))
 188                 status = -EINVAL;
 189         else {
 190                 cdev->deactivations--;
 191                 if (cdev->deactivations == 0)
 192                         status = usb_gadget_connect(cdev->gadget);
 193         }
 194
 195         spin_unlock(&cdev->lock);
 196         return status;
 197 }
 198
 199 /**
 200  * usb_interface_id() - allocate an unused interface ID
 201  * @config: configuration associated with the interface
 202  * @function: function handling the interface
 203  * Context: single threaded during gadget setup
 204  *
 205  * usb_interface_id() is called from usb_function.bind() callbacks to
 206  * allocate new interface IDs.  The function driver will then store that
 207  * ID in interface, association, CDC union, and other descriptors.  It
 208  * will also handle any control requests targeted at that interface,
 209  * particularly changing its altsetting via set_alt().  There may
 210  * also be class-specific or vendor-specific requests to handle.
 211  *
 212  * All interface identifier should be allocated using this routine, to
 213  * ensure that for example different functions don't wrongly assign
 214  * different meanings to the same identifier.  Note that since interface
 215  * identifiers are configuration-specific, functions used in more than
 216  * one configuration (or more than once in a given configuration) need
 217  * multiple versions of the relevant descriptors.
 218  *
 219  * Returns the interface ID which was allocated; or -ENODEV if no
 220  * more interface IDs can be allocated.
 221  */
 222 int usb_interface_id(struct usb_configuration *config,
 223                 struct usb_function *function)
 224 {
 225         unsigned id = config->next_interface_id;
 226
 227         if (id < MAX_CONFIG_INTERFACES) {
 228                 config->interface[id] = function;
 229                 config->next_interface_id = id + 1;
 230                 return id;
 231         }
 232         return -ENODEV;
 233 }
 234
 235 static int config_buf(struct usb_configuration *config,
 236                 enum usb_device_speed speed, void *buf, u8 type)
 237 {
 238         struct usb_config_descriptor    *c = buf;
 239         void                            *next = buf + USB_DT_CONFIG_SIZE;
 240         int                             len = USB_BUFSIZ - USB_DT_CONFIG_SIZE;
 241         struct usb_function             *f;
 242         int                             status;
 243
 244         /* write the config descriptor */
 245         c = buf;
 246         c->bLength = USB_DT_CONFIG_SIZE;
 247         c->bDescriptorType = type;
 248         /* wTotalLength is written later */
 249         c->bNumInterfaces = config->next_interface_id;
 250         c->bConfigurationValue = config->bConfigurationValue;
 251         c->iConfiguration = config->iConfiguration;
 252         c->bmAttributes = USB_CONFIG_ATT_ONE | config->bmAttributes;
 253         c->bMaxPower = config->bMaxPower ? : (CONFIG_USB_GADGET_VBUS_DRAW / 2);
 254
 255         /* There may be e.g. OTG descriptors */
 256         if (config->descriptors) {
 257                 status = usb_descriptor_fillbuf(next, len,
 258                                 config->descriptors);
 259                 if (status < 0)
 260                         return status;
 261                 len -= status;
 262                 next += status;
 263         }
 264
 265         /* add each function's descriptors */
 266         list_for_each_entry(f, &config->functions, list) {
 267                 struct usb_descriptor_header **descriptors;
 268
 269                 if (speed == USB_SPEED_HIGH)
 270                         descriptors = f->hs_descriptors;
 271                 else
 272                         descriptors = f->descriptors;
 273                 if (!descriptors)
 274                         continue;
 275                 status = usb_descriptor_fillbuf(next, len,
 276                         (const struct usb_descriptor_header **) descriptors);
 277                 if (status < 0)
 278                         return status;
 279                 len -= status;
 280                 next += status;
 281         }
 282
 283         len = next - buf;
 284         c->wTotalLength = cpu_to_le16(len);
 285         return len;
 286 }
 287
 288 static int config_desc(struct usb_composite_dev *cdev, unsigned w_value)
 289 {
 290         struct usb_gadget               *gadget = cdev->gadget;
 291         struct usb_configuration        *c;
 292         u8                              type = w_value >> 8;
 293         enum usb_device_speed           speed = USB_SPEED_UNKNOWN;
 294
 295         if (gadget_is_dualspeed(gadget)) {
 296                 int                     hs = 0;
 297
 298                 if (gadget->speed == USB_SPEED_HIGH)
 299                         hs = 1;
 300                 if (type == USB_DT_OTHER_SPEED_CONFIG)
 301                         hs = !hs;
 302                 if (hs)
 303                         speed = USB_SPEED_HIGH;
 304
 305         }
 306
 307         /* This is a lookup by config *INDEX* */
 308         w_value &= 0xff;
 309         list_for_each_entry(c, &cdev->configs, list) {
 310                 /* ignore configs that won't work at this speed */
 311                 if (speed == USB_SPEED_HIGH) {
 312                         if (!c->highspeed)
 313                                 continue;
 314                 } else {
 315                         if (!c->fullspeed)
 316                                 continue;
 317                 }
 318                 if (w_value == 0)
 319                         return config_buf(c, speed, cdev->req->buf, type);
 320                 w_value--;
 321         }
 322         return -EINVAL;
 323 }
 324
 325 static int count_configs(struct usb_composite_dev *cdev, unsigned type)
 326 {
 327         struct usb_gadget               *gadget = cdev->gadget;
 328         struct usb_configuration        *c;
 329         unsigned                        count = 0;
 330         int                             hs = 0;
 331
 332         if (gadget_is_dualspeed(gadget)) {
 333                 if (gadget->speed == USB_SPEED_HIGH)
 334                         hs = 1;
 335                 if (type == USB_DT_DEVICE_QUALIFIER)
 336                         hs = !hs;
 337         }
 338         list_for_each_entry(c, &cdev->configs, list) {
 339                 /* ignore configs that won't work at this speed */
 340                 if (hs) {
 341                         if (!c->highspeed)
 342                                 continue;
 343                 } else {
 344                         if (!c->fullspeed)
 345                                 continue;
 346                 }
 347                 count++;
 348         }
 349         return count;
 350 }
 351
 352 static void device_qual(struct usb_composite_dev *cdev)
 353 {
 354         struct usb_qualifier_descriptor *qual = cdev->req->buf;
 355
 356         qual->bLength = sizeof(*qual);
 357         qual->bDescriptorType = USB_DT_DEVICE_QUALIFIER;
 358         /* POLICY: same bcdUSB and device type info at both speeds */
 359         qual->bcdUSB = cdev->desc.bcdUSB;
 360         qual->bDeviceClass = cdev->desc.bDeviceClass;
 361         qual->bDeviceSubClass = cdev->desc.bDeviceSubClass;
 362         qual->bDeviceProtocol = cdev->desc.bDeviceProtocol;
 363         /* ASSUME same EP0 fifo size at both speeds */
 364         qual->bMaxPacketSize0 = cdev->desc.bMaxPacketSize0;
 365         qual->bNumConfigurations = count_configs(cdev, USB_DT_DEVICE_QUALIFIER);
 366         qual->bRESERVED = 0;
 367 }
 368
 369 /*-------------------------------------------------------------------------*/
 370
 371 static void reset_config(struct usb_composite_dev *cdev)
 372 {
 373         struct usb_function             *f;
 374
 375         DBG(cdev, "reset config\n");
 376
 377         list_for_each_entry(f, &cdev->config->functions, list) {
 378                 if (f->disable)
 379                         f->disable(f);
 380
 381                 bitmap_zero(f->endpoints, 32);
 382         }
 383         cdev->config = NULL;
 384 }
 385
 386 static int set_config(struct usb_composite_dev *cdev,
 387                 const struct usb_ctrlrequest *ctrl, unsigned number)
 388 {
 389         struct usb_gadget       *gadget = cdev->gadget;
 390         struct usb_configuration *c = NULL;
 391         int                     result = -EINVAL;
 392         unsigned                power = gadget_is_otg(gadget) ? 8 : 100;
 393         int                     tmp;
 394
 395         if (cdev->config)
 396                 reset_config(cdev);
 397
 398         if (number) {
 399                 list_for_each_entry(c, &cdev->configs, list) {
 400                         if (c->bConfigurationValue == number) {
 401                                 result = 0;
 402                                 break;
 403                         }
 404                 }
 405                 if (result < 0)
 406                         goto done;
 407         } else
 408                 result = 0;
 409
 410         INFO(cdev, "%s speed config #%d: %s\n",
 411                 ({ char *speed;
 412                 switch (gadget->speed) {
 413                 case USB_SPEED_LOW:     speed = "low"; break;
 414                 case USB_SPEED_FULL:    speed = "full"; break;
 415                 case USB_SPEED_HIGH:    speed = "high"; break;
 416                 default:                speed = "?"; break;
 417                 } ; speed; }), number, c ? c->label : "unconfigured");
 418
 419         if (!c)
 420                 goto done;
 421
 422         cdev->config = c;
 423
 424         /* reset delay status to zero every time usb reconnect */
 425         cdev->delayed_status = 0;
 426
 427         /* Initialize all interfaces by setting them to altsetting zero. */
 428         for (tmp = 0; tmp < MAX_CONFIG_INTERFACES; tmp++) {
 429                 struct usb_function     *f = c->interface[tmp];
 430                 struct usb_descriptor_header **descriptors;
 431
 432                 if (!f)
 433                         break;
 434
 435                 /*
 436                  * Record which endpoints are used by the function. This is used
 437                  * to dispatch control requests targeted at that endpoint to the
 438                  * function's setup callback instead of the current
 439                  * configuration's setup callback.
 440                  */
 441                 if (gadget->speed == USB_SPEED_HIGH)
 442                         descriptors = f->hs_descriptors;
 443                 else
 444                         descriptors = f->descriptors;
 445
 446                 for (; *descriptors; ++descriptors) {
 447                         struct usb_endpoint_descriptor *ep;
 448                         int addr;
 449
 450                         if ((*descriptors)->bDescriptorType != USB_DT_ENDPOINT)
 451                                 continue;
 452
 453                         ep = (struct usb_endpoint_descriptor *)*descriptors;
 454                         addr = ((ep->bEndpointAddress & 0x80) >> 3)
 455                              |  (ep->bEndpointAddress & 0x0f);
 456                         set_bit(addr, f->endpoints);
 457                 }
 458
 459                 result = f->set_alt(f, tmp, 0);
 460                 if (result < 0) {
 461                         DBG(cdev, "interface %d (%s/%p) alt 0 --> %d\n",
 462                                         tmp, f->name, f, result);
 463
 464                         reset_config(cdev);
 465                         goto done;
 466                 }
 467
 468                 if (result == USB_GADGET_DELAYED_STATUS) {
 469                         DBG(cdev,
 470                          "%s: interface %d (%s) requested delayed status\n",
 471                                         __func__, tmp, f->name);
 472                         cdev->delayed_status++;
 473                         DBG(cdev, "delayed_status count %d\n",
 474                                         cdev->delayed_status);
 475                 }
 476         }
 477
 478         /* when we return, be sure our power usage is valid */
 479         power = c->bMaxPower ? (2 * c->bMaxPower) : CONFIG_USB_GADGET_VBUS_DRAW;
 480
 481         /* usb gadget connect flag */
 482         gadget_connected = 1;
 483 done:
 484         usb_gadget_vbus_draw(gadget, power);
 485
 486         if (result >= 0 && cdev->delayed_status)
 487                 result = USB_GADGET_DELAYED_STATUS;
 488         return result;
 489 }
 490
 491 /**
 492  * usb_add_config() - add a configuration to a device.
 493  * @cdev: wraps the USB gadget
 494  * @config: the configuration, with bConfigurationValue assigned
 495  * @bind: the configuration's bind function
 496  * Context: single threaded during gadget setup
 497  *
 498  * One of the main tasks of a composite @bind() routine is to
 499  * add each of the configurations it supports, using this routine.
 500  *
 501  * This function returns the value of the configuration's @bind(), which
 502  * is zero for success else a negative errno value.  Binding configurations
 503  * assigns global resources including string IDs, and per-configuration
 504  * resources such as interface IDs and endpoints.
 505  */
 506 int usb_add_config(struct usb_composite_dev *cdev,
 507                 struct usb_configuration *config,
 508                 int (*bind)(struct usb_configuration *))
 509 {
 510         int                             status = -EINVAL;
 511         struct usb_configuration        *c;
 512
 513         DBG(cdev, "adding config #%u '%s'/%p\n",
 514                         config->bConfigurationValue,
 515                         config->label, config);
 516
 517         if (!config->bConfigurationValue || !bind)
 518                 goto done;
 519
 520         /* Prevent duplicate configuration identifiers */
 521         list_for_each_entry(c, &cdev->configs, list) {
 522                 if (c->bConfigurationValue == config->bConfigurationValue) {
 523                         printk("usb_add_config, already configed,everest\n");
 524                         status = -EBUSY;
 525                         goto done;
 526                 }
 527         }
 528
 529         config->cdev = cdev;
 530         list_add_tail(&config->list, &cdev->configs);
 531
 532         INIT_LIST_HEAD(&config->functions);
 533         config->next_interface_id = 0;
 534         memset(config->interface, '\0', sizeof(config->interface));
 535
 536         status = bind(config);
 537         if (status < 0) {
 538                 list_del(&config->list);
 539                 config->cdev = NULL;
 540         } else {
 541                 unsigned        i;
 542
 543                 DBG(cdev, "cfg %d/%p speeds:%s%s\n",
 544                         config->bConfigurationValue, config,
 545                         config->highspeed ? " high" : "",
 546                         config->fullspeed
 547                                 ? (gadget_is_dualspeed(cdev->gadget)
 548                                         ? " full"
 549                                         : " full/low")
 550                                 : "");
 551
 552                 for (i = 0; i < MAX_CONFIG_INTERFACES; i++) {
 553                         struct usb_function     *f = config->interface[i];
 554
 555                         if (!f)
 556                                 continue;
 557                         DBG(cdev, "  interface %d = %s/%p\n",
 558                                 i, f->name, f);
 559                 }
 560         }
 561
 562         /* set_alt(), or next bind(), sets up
 563          * ep->driver_data as needed.
 564          */
 565         usb_ep_autoconfig_reset(cdev->gadget);
 566
 567 done:
 568         if (status)
 569                 DBG(cdev, "added config '%s'/%u --> %d\n", config->label,
 570                                 config->bConfigurationValue, status);
 571         return status;
 572 }
 573
 574 static int unbind_config(struct usb_composite_dev *cdev,
 575                               struct usb_configuration *config)
 576 {
 577         while (!list_empty(&config->functions)) {
 578                 struct usb_function             *f;
 579
 580                 f = list_first_entry(&config->functions,
 581                                 struct usb_function, list);
 582                 list_del(&f->list);
 583                 if (f->unbind) {
 584                         DBG(cdev, "unbind function '%s'/%p\n", f->name, f);
 585                         f->unbind(config, f);
 586                         /* may free memory for "f" */
 587                 }
 588         }
 589         if (config->unbind) {
 590                 DBG(cdev, "unbind config '%s'/%p\n", config->label, config);
 591                 config->unbind(config);
 592                         /* may free memory for "c" */
 593         }
 594         return 0;
 595 }
 596
 597 int usb_remove_config(struct usb_composite_dev *cdev,
 598                       struct usb_configuration *config)
 599 {
 600         unsigned long flags;
 601
 602         spin_lock_irqsave(&cdev->lock, flags);
 603
 604         if (cdev->config == config)
 605                 reset_config(cdev);
 606
 607         list_del(&config->list);
 608
 609         spin_unlock_irqrestore(&cdev->lock, flags);
 610
 611         return unbind_config(cdev, config);
 612 }
 613
 614 /*-------------------------------------------------------------------------*/
 615
 616 /* We support strings in multiple languages ... string descriptor zero
 617  * says which languages are supported.  The typical case will be that
 618  * only one language (probably English) is used, with I18N handled on
 619  * the host side.
 620  */
 621
 622 static void collect_langs(struct usb_gadget_strings **sp, __le16 *buf)
 623 {
 624         const struct usb_gadget_strings *s;
 625         u16                             language;
 626         __le16                          *tmp;
 627
 628         while (*sp) {
 629                 s = *sp;
 630                 language = cpu_to_le16(s->language);
 631                 for (tmp = buf; *tmp && tmp < &buf[126]; tmp++) {
 632                         if (*tmp == language)
 633                                 goto repeat;
 634                 }
 635                 *tmp++ = language;
 636 repeat:
 637                 sp++;
 638         }
 639 }
 640
 641 static int lookup_string(
 642         struct usb_gadget_strings       **sp,
 643         void                            *buf,
 644         u16                             language,
 645         int                             id
 646 )
 647 {
 648         struct usb_gadget_strings       *s;
 649         int                             value;
 650
 651         while (*sp) {
 652                 s = *sp++;
 653                 if (s->language != language)
 654                         continue;
 655                 value = usb_gadget_get_string(s, id, buf);
 656                 if (value > 0)
 657                         return value;
 658         }
 659         return -EINVAL;
 660 }
 661
 662 static int get_string(struct usb_composite_dev *cdev,
 663                 void *buf, u16 language, int id)
 664 {
 665         struct usb_configuration        *c;
 666         struct usb_function             *f;
 667         int                             len;
 668         const char                      *str;
 669
 670         /* Yes, not only is USB's I18N support probably more than most
 671          * folk will ever care about ... also, it's all supported here.
 672          * (Except for UTF8 support for Unicode's "Astral Planes".)
 673          */
 674
 675         /* 0 == report all available language codes */
 676         if (id == 0) {
 677                 struct usb_string_descriptor    *s = buf;
 678                 struct usb_gadget_strings       **sp;
 679
 680                 memset(s, 0, 256);
 681                 s->bDescriptorType = USB_DT_STRING;
 682
 683                 sp = composite->strings;
 684                 if (sp)
 685                         collect_langs(sp, s->wData);
 686
 687                 list_for_each_entry(c, &cdev->configs, list) {
 688                         sp = c->strings;
 689                         if (sp)
 690                                 collect_langs(sp, s->wData);
 691
 692                         list_for_each_entry(f, &c->functions, list) {
 693                                 sp = f->strings;
 694                                 if (sp)
 695                                         collect_langs(sp, s->wData);
 696                         }
 697                 }
 698
 699                 for (len = 0; len <= 126 && s->wData[len]; len++)
 700                         continue;
 701                 if (!len)
 702                         return -EINVAL;
 703
 704                 s->bLength = 2 * (len + 1);
 705                 return s->bLength;
 706         }
 707
 708         /* Otherwise, look up and return a specified string.  First
 709          * check if the string has not been overridden.
 710          */
 711         if (cdev->manufacturer_override == id)
 712                 str = iManufacturer ?: composite->iManufacturer ?:
 713                         composite_manufacturer;
 714         else if (cdev->product_override == id)
 715                 str = iProduct ?: composite->iProduct;
 716         else if (cdev->serial_override == id)
 717                 str = iSerialNumber;
 718         else
 719                 str = NULL;
 720         if (str) {
 721                 struct usb_gadget_strings strings = {
 722                         .language = language,
 723                         .strings  = &(struct usb_string) { 0xff, str }
 724                 };
 725                 return usb_gadget_get_string(&strings, 0xff, buf);
 726         }
 727
 728         /* String IDs are device-scoped, so we look up each string
 729          * table we're told about.  These lookups are infrequent;
 730          * simpler-is-better here.
 731          */
 732         if (composite->strings) {
 733                 len = lookup_string(composite->strings, buf, language, id);
 734                 if (len > 0)
 735                         return len;
 736         }
 737         list_for_each_entry(c, &cdev->configs, list) {
 738                 if (c->strings) {
 739                         len = lookup_string(c->strings, buf, language, id);
 740                         if (len > 0)
 741                                 return len;
 742                 }
 743                 list_for_each_entry(f, &c->functions, list) {
 744                         if (!f->strings)
 745                                 continue;
 746                         len = lookup_string(f->strings, buf, language, id);
 747                         if (len > 0)
 748                                 return len;
 749                 }
 750         }
 751         return -EINVAL;
 752 }
 753
 754 /**
 755  * usb_string_id() - allocate an unused string ID
 756  * @cdev: the device whose string descriptor IDs are being allocated
 757  * Context: single threaded during gadget setup
 758  *
 759  * @usb_string_id() is called from bind() callbacks to allocate
 760  * string IDs.  Drivers for functions, configurations, or gadgets will
 761  * then store that ID in the appropriate descriptors and string table.
 762  *
 763  * All string identifier should be allocated using this,
 764  * @usb_string_ids_tab() or @usb_string_ids_n() routine, to ensure
 765  * that for example different functions don't wrongly assign different
 766  * meanings to the same identifier.
 767  */
 768 int usb_string_id(struct usb_composite_dev *cdev)
 769 {
 770         if (cdev->next_string_id < 254) {
 771                 /* string id 0 is reserved by USB spec for list of
 772                  * supported languages */
 773                 /* 255 reserved as well? -- mina86 */
 774                 cdev->next_string_id++;
 775                 return cdev->next_string_id;
 776         }
 777         return -ENODEV;
 778 }
 779
 780 /**
 781  * usb_string_ids() - allocate unused string IDs in batch
 782  * @cdev: the device whose string descriptor IDs are being allocated
 783  * @str: an array of usb_string objects to assign numbers to
 784  * Context: single threaded during gadget setup
 785  *
 786  * @usb_string_ids() is called from bind() callbacks to allocate
 787  * string IDs.  Drivers for functions, configurations, or gadgets will
 788  * then copy IDs from the string table to the appropriate descriptors
 789  * and string table for other languages.
 790  *
 791  * All string identifier should be allocated using this,
 792  * @usb_string_id() or @usb_string_ids_n() routine, to ensure that for
 793  * example different functions don't wrongly assign different meanings
 794  * to the same identifier.
 795  */
 796 int usb_string_ids_tab(struct usb_composite_dev *cdev, struct usb_string *str)
 797 {
 798         int next = cdev->next_string_id;
 799
 800         for (; str->s; ++str) {
 801                 if (unlikely(next >= 254))
 802                         return -ENODEV;
 803                 str->id = ++next;
 804         }
 805
 806         cdev->next_string_id = next;
 807
 808         return 0;
 809 }
 810
 811 /**
 812  * usb_string_ids_n() - allocate unused string IDs in batch
 813  * @c: the device whose string descriptor IDs are being allocated
 814  * @n: number of string IDs to allocate
 815  * Context: single threaded during gadget setup
 816  *
 817  * Returns the first requested ID.  This ID and next @n-1 IDs are now
 818  * valid IDs.  At least provided that @n is non-zero because if it
 819  * is, returns last requested ID which is now very useful information.
 820  *
 821  * @usb_string_ids_n() is called from bind() callbacks to allocate
 822  * string IDs.  Drivers for functions, configurations, or gadgets will
 823  * then store that ID in the appropriate descriptors and string table.
 824  *
 825  * All string identifier should be allocated using this,
 826  * @usb_string_id() or @usb_string_ids_n() routine, to ensure that for
 827  * example different functions don't wrongly assign different meanings
 828  * to the same identifier.
 829  */
 830 int usb_string_ids_n(struct usb_composite_dev *c, unsigned n)
 831 {
 832         unsigned next = c->next_string_id;
 833         if (unlikely(n > 254 || (unsigned)next + n > 254))
 834                 return -ENODEV;
 835         c->next_string_id += n;
 836         return next + 1;
 837 }
 838
 839
 840 /*-------------------------------------------------------------------------*/
 841
 842 static void composite_setup_complete(struct usb_ep *ep, struct usb_request *req)
 843 {
 844         if (req->status || req->actual != req->length)
 845                 DBG((struct usb_composite_dev *) ep->driver_data,
 846                                 "setup complete --> %d, %d/%d\n",
 847                                 req->status, req->actual, req->length);
 848 }
 849
 850 /*
 851  * The setup() callback implements all the ep0 functionality that's
 852  * not handled lower down, in hardware or the hardware driver(like
 853  * device and endpoint feature flags, and their status).  It's all
 854  * housekeeping for the gadget function we're implementing.  Most of
 855  * the work is in config and function specific setup.
 856  */
 857 static int
 858 composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
 859 {
 860         struct usb_composite_dev        *cdev = get_gadget_data(gadget);
 861         struct usb_request              *req = cdev->req;
 862         int                             value = -EOPNOTSUPP;
 863         u16                             w_index = le16_to_cpu(ctrl->wIndex);
 864         u8                              intf = w_index & 0xFF;
 865         u16                             w_value = le16_to_cpu(ctrl->wValue);
 866         u16                             w_length = le16_to_cpu(ctrl->wLength);
 867         struct usb_function             *f = NULL;
 868         u8                              endp;
 869
 870         /* partial re-init of the response message; the function or the
 871          * gadget might need to intercept e.g. a control-OUT completion
 872          * when we delegate to it.
 873          */
 874         req->zero = 0;
 875         req->complete = composite_setup_complete;
 876         req->length = 0;
 877         gadget->ep0->driver_data = cdev;
 878
 879         switch (ctrl->bRequest) {
 880
 881         /* we handle all standard USB descriptors */
 882         case USB_REQ_GET_DESCRIPTOR:
 883                 if (ctrl->bRequestType != USB_DIR_IN)
 884                         goto unknown;
 885                 switch (w_value >> 8) {
 886
 887                 case USB_DT_DEVICE:
 888                         cdev->desc.bNumConfigurations =
 889                                 count_configs(cdev, USB_DT_DEVICE);
 890                         value = min(w_length, (u16) sizeof cdev->desc);
 891                         memcpy(req->buf, &cdev->desc, value);
 892                         break;
 893                 case USB_DT_DEVICE_QUALIFIER:
 894                         if (!gadget_is_dualspeed(gadget))
 895                                 break;
 896                         device_qual(cdev);
 897                         value = min_t(int, w_length,
 898                                 sizeof(struct usb_qualifier_descriptor));
 899                         break;
 900                 case USB_DT_OTHER_SPEED_CONFIG:
 901                         if (!gadget_is_dualspeed(gadget))
 902                                 break;
 903                         /* FALLTHROUGH */
 904                 case USB_DT_CONFIG:
 905                         value = config_desc(cdev, w_value);
 906                         if (value >= 0)
 907                                 value = min(w_length, (u16) value);
 908                         break;
 909                 case USB_DT_STRING:
 910                         value = get_string(cdev, req->buf,
 911                                         w_index, w_value & 0xff);
 912                         if (value >= 0)
 913                                 value = min(w_length, (u16) value);
 914                         break;
 915                 }
 916                 break;
 917
 918         /* any number of configs can work */
 919         case USB_REQ_SET_CONFIGURATION:
 920                 if (ctrl->bRequestType != 0)
 921                         goto unknown;
 922                 if (gadget_is_otg(gadget)) {
 923                         if (gadget->a_hnp_support)
 924                                 DBG(cdev, "HNP available\n");
 925                         else if (gadget->a_alt_hnp_support)
 926                                 DBG(cdev, "HNP on another port\n");
 927                         else
 928                                 VDBG(cdev, "HNP inactive\n");
 929                 }
 930                 spin_lock(&cdev->lock);
 931                 value = set_config(cdev, ctrl, w_value);
 932                 spin_unlock(&cdev->lock);
 933                 break;
 934         case USB_REQ_GET_CONFIGURATION:
 935                 if (ctrl->bRequestType != USB_DIR_IN)
 936                         goto unknown;
 937                 if (cdev->config)
 938                         *(u8 *)req->buf = cdev->config->bConfigurationValue;
 939                 else
 940                         *(u8 *)req->buf = 0;
 941                 value = min(w_length, (u16) 1);
 942                 break;
 943
 944         /* function drivers must handle get/set altsetting; if there's
 945          * no get() method, we know only altsetting zero works.
 946          */
 947         case USB_REQ_SET_INTERFACE:
 948                 if (ctrl->bRequestType != USB_RECIP_INTERFACE)
 949                         goto unknown;
 950                 if (!cdev->config || intf >= MAX_CONFIG_INTERFACES)
 951                         break;
 952                 f = cdev->config->interface[intf];
 953                 if (!f)
 954                         break;
 955                 if (w_value && !f->set_alt)
 956                         break;
 957                 value = f->set_alt(f, w_index, w_value);
 958                 if (value == USB_GADGET_DELAYED_STATUS) {
 959                         DBG(cdev,
 960                          "%s: interface %d (%s) requested delayed status\n",
 961                                         __func__, intf, f->name);
 962                         cdev->delayed_status++;
 963                         DBG(cdev, "delayed_status count %d\n",
 964                                         cdev->delayed_status);
 965                 }
 966                 break;
 967         case USB_REQ_GET_INTERFACE:
 968                 if (ctrl->bRequestType != (USB_DIR_IN|USB_RECIP_INTERFACE))
 969                         goto unknown;
 970                 if (!cdev->config || intf >= MAX_CONFIG_INTERFACES)
 971                         break;
 972                 f = cdev->config->interface[intf];
 973                 if (!f)
 974                         break;
 975                 /* lots of interfaces only need altsetting zero... */
 976                 value = f->get_alt ? f->get_alt(f, w_index) : 0;
 977                 if (value < 0)
 978                         break;
 979                 *((u8 *)req->buf) = value;
 980                 value = min(w_length, (u16) 1);
 981                 break;
 982         default:
 983 unknown:
 984                 VDBG(cdev,
 985                         "non-core control req%02x.%02x v%04x i%04x l%d\n",
 986                         ctrl->bRequestType, ctrl->bRequest,
 987                         w_value, w_index, w_length);
 988
 989                 /* functions always handle their interfaces and endpoints...
 990                  * punt other recipients (other, WUSB, ...) to the current
 991                  * configuration code.
 992                  *
 993                  * REVISIT it could make sense to let the composite device
 994                  * take such requests too, if that's ever needed:  to work
 995                  * in config 0, etc.
 996                  */
 997                 switch (ctrl->bRequestType & USB_RECIP_MASK) {
 998                 case USB_RECIP_INTERFACE:
 999                         if (!cdev->config || intf >= MAX_CONFIG_INTERFACES)
1000                                 break;
1001                         f = cdev->config->interface[intf];
1002                         break;
1003
1004                 case USB_RECIP_ENDPOINT:
1005                         endp = ((w_index & 0x80) >> 3) | (w_index & 0x0f);
1006                         list_for_each_entry(f, &cdev->config->functions, list) {
1007                                 if (test_bit(endp, f->endpoints))
1008                                         break;
1009                         }
1010                         if (&f->list == &cdev->config->functions)
1011                                 f = NULL;
1012                         break;
1013                 }
1014
1015                 if (f && f->setup)
1016                         value = f->setup(f, ctrl);
1017                 else {
1018                         struct usb_configuration        *c;
1019
1020                         c = cdev->config;
1021                         if (c && c->setup)
1022                                 value = c->setup(c, ctrl);
1023                 }
1024
1025                 goto done;
1026         }
1027
1028         /* respond with data transfer before status phase? */
1029         if (value >= 0 && value != USB_GADGET_DELAYED_STATUS) {
1030                 req->length = value;
1031                 req->zero = value < w_length;
1032                 value = usb_ep_queue(gadget->ep0, req, GFP_ATOMIC);
1033                 if (value < 0) {
1034                         DBG(cdev, "ep_queue --> %d\n", value);
1035                         req->status = 0;
1036                         composite_setup_complete(gadget->ep0, req);
1037                 }
1038         } else if (value == USB_GADGET_DELAYED_STATUS && w_length != 0) {
1039                 WARN(cdev,
1040                         "%s: Delayed status not supported for w_length != 0",
1041                         __func__);
1042         }
1043
1044 done:
1045         /* device either stalls (value < 0) or reports success */
1046         return value;
1047 }
1048
1049 static void composite_disconnect(struct usb_gadget *gadget)
1050 {
1051         struct usb_composite_dev        *cdev = get_gadget_data(gadget);
1052         unsigned long                   flags;
1053
1054         /* REVISIT:  should we have config and device level
1055          * disconnect callbacks?
1056          */
1057         spin_lock_irqsave(&cdev->lock, flags);
1058         if (cdev->config)
1059                 reset_config(cdev);
1060         if (composite->disconnect)
1061                 composite->disconnect(cdev);
1062         /* usb gadget connect flag */
1063         gadget_connected = 0;
1064         spin_unlock_irqrestore(&cdev->lock, flags);
1065 }
1066
1067 /*-------------------------------------------------------------------------*/
1068 int get_gadget_connect_flag( void )
1069 {
1070     return gadget_connected;
1071 }
1072 EXPORT_SYMBOL(get_gadget_connect_flag);
1073
1074 static ssize_t composite_show_suspended(struct device *dev,
1075                                         struct device_attribute *attr,
1076                                         char *buf)
1077 {
1078         struct usb_gadget *gadget = dev_to_usb_gadget(dev);
1079         struct usb_composite_dev *cdev = get_gadget_data(gadget);
1080
1081         return sprintf(buf, "%d\n", cdev->suspended);
1082 }
1083
1084 static DEVICE_ATTR(suspended, 0444, composite_show_suspended, NULL);
1085
1086 static void
1087 composite_unbind(struct usb_gadget *gadget)
1088 {
1089         struct usb_composite_dev        *cdev = get_gadget_data(gadget);
1090
1091         /* composite_disconnect() must already have been called
1092          * by the underlying peripheral controller driver!
1093          * so there's no i/o concurrency that could affect the
1094          * state protected by cdev->lock.
1095          */
1096         WARN_ON(cdev->config);
1097
1098         while (!list_empty(&cdev->configs)) {
1099                 struct usb_configuration        *c;
1100                 c = list_first_entry(&cdev->configs,
1101                                 struct usb_configuration, list);
1102                 list_del(&c->list);
1103                 unbind_config(cdev, c);
1104         }
1105         if (composite->unbind)
1106                 composite->unbind(cdev);
1107
1108         if (cdev->req) {
1109                 kfree(cdev->req->buf);
1110                 usb_ep_free_request(gadget->ep0, cdev->req);
1111         }
1112         device_remove_file(&gadget->dev, &dev_attr_suspended);
1113         kfree(cdev);
1114         set_gadget_data(gadget, NULL);
1115         composite = NULL;
1116 }
1117
1118 static u8 override_id(struct usb_composite_dev *cdev, u8 *desc)
1119 {
1120         if (!*desc) {
1121                 int ret = usb_string_id(cdev);
1122                 if (unlikely(ret < 0))
1123                         WARNING(cdev, "failed to override string ID\n");
1124                 else
1125                         *desc = ret;
1126         }
1127
1128         return *desc;
1129 }
1130
1131 static int composite_bind(struct usb_gadget *gadget)
1132 {
1133         struct usb_composite_dev        *cdev;
1134         int                             status = -ENOMEM;
1135
1136         cdev = kzalloc(sizeof *cdev, GFP_KERNEL);
1137         if (!cdev)
1138                 return status;
1139
1140         spin_lock_init(&cdev->lock);
1141         cdev->gadget = gadget;
1142         set_gadget_data(gadget, cdev);
1143         INIT_LIST_HEAD(&cdev->configs);
1144
1145         /* preallocate control response and buffer */
1146         cdev->req = usb_ep_alloc_request(gadget->ep0, GFP_KERNEL);
1147         if (!cdev->req)
1148                 goto fail;
1149         cdev->req->buf = kmalloc(USB_BUFSIZ, GFP_KERNEL);
1150         if (!cdev->req->buf)
1151                 goto fail;
1152         cdev->req->complete = composite_setup_complete;
1153         gadget->ep0->driver_data = cdev;
1154
1155         cdev->bufsiz = USB_BUFSIZ;
1156         cdev->driver = composite;
1157
1158         /*
1159          * As per USB compliance update, a device that is actively drawing
1160          * more than 100mA from USB must report itself as bus-powered in
1161          * the GetStatus(DEVICE) call.
1162          */
1163         if (CONFIG_USB_GADGET_VBUS_DRAW <= USB_SELF_POWER_VBUS_MAX_DRAW)
1164                 usb_gadget_set_selfpowered(gadget);
1165
1166         /* interface and string IDs start at zero via kzalloc.
1167          * we force endpoints to start unassigned; few controller
1168          * drivers will zero ep->driver_data.
1169          */
1170         usb_ep_autoconfig_reset(cdev->gadget);
1171
1172         /* composite gadget needs to assign strings for whole device (like
1173          * serial number), register function drivers, potentially update
1174          * power state and consumption, etc
1175          */
1176         status = composite_gadget_bind(cdev);
1177         if (status < 0)
1178                 goto fail;
1179
1180         cdev->desc = *composite->dev;
1181         cdev->desc.bMaxPacketSize0 = gadget->ep0->maxpacket;
1182
1183         /* standardized runtime overrides for device ID data */
1184         if (idVendor)
1185                 cdev->desc.idVendor = cpu_to_le16(idVendor);
1186         if (idProduct)
1187                 cdev->desc.idProduct = cpu_to_le16(idProduct);
1188         if (bcdDevice)
1189                 cdev->desc.bcdDevice = cpu_to_le16(bcdDevice);
1190
1191         /* string overrides */
1192         if (iManufacturer || !cdev->desc.iManufacturer) {
1193                 if (!iManufacturer && !composite->iManufacturer &&
1194                     !*composite_manufacturer)
1195                         snprintf(composite_manufacturer,
1196                                  sizeof composite_manufacturer,
1197                                  "%s %s with %s",
1198                                  init_utsname()->sysname,
1199                                  init_utsname()->release,
1200                                  gadget->name);
1201
1202                 cdev->manufacturer_override =
1203                         override_id(cdev, &cdev->desc.iManufacturer);
1204         }
1205
1206         if (iProduct || (!cdev->desc.iProduct && composite->iProduct))
1207                 cdev->product_override =
1208                         override_id(cdev, &cdev->desc.iProduct);
1209
1210         if (iSerialNumber)
1211                 cdev->serial_override =
1212                         override_id(cdev, &cdev->desc.iSerialNumber);
1213
1214         /* has userspace failed to provide a serial number? */
1215         if (composite->needs_serial && !cdev->desc.iSerialNumber)
1216                 WARNING(cdev, "userspace failed to provide iSerialNumber\n");
1217
1218         /* finish up */
1219         status = device_create_file(&gadget->dev, &dev_attr_suspended);
1220         if (status)
1221                 goto fail;
1222
1223         INFO(cdev, "%s ready\n", composite->name);
1224         return 0;
1225
1226 fail:
1227         composite_unbind(gadget);
1228         return status;
1229 }
1230
1231 /*-------------------------------------------------------------------------*/
1232
1233 static void
1234 composite_suspend(struct usb_gadget *gadget)
1235 {
1236         struct usb_composite_dev        *cdev = get_gadget_data(gadget);
1237         struct usb_function             *f;
1238
1239         /* REVISIT:  should we have config level
1240          * suspend/resume callbacks?
1241          */
1242         DBG(cdev, "suspend\n");
1243         if (cdev->config) {
1244                 list_for_each_entry(f, &cdev->config->functions, list) {
1245                         if (f->suspend)
1246                                 f->suspend(f);
1247                 }
1248         }
1249         if (composite->suspend)
1250                 composite->suspend(cdev);
1251
1252         cdev->suspended = 1;
1253
1254         usb_gadget_vbus_draw(gadget, 2);
1255 }
1256
1257 static void
1258 composite_resume(struct usb_gadget *gadget)
1259 {
1260         struct usb_composite_dev        *cdev = get_gadget_data(gadget);
1261         struct usb_function             *f;
1262         u8                              maxpower;
1263
1264         /* REVISIT:  should we have config level
1265          * suspend/resume callbacks?
1266          */
1267         DBG(cdev, "resume\n");
1268         if (composite->resume)
1269                 composite->resume(cdev);
1270         if (cdev->config) {
1271                 list_for_each_entry(f, &cdev->config->functions, list) {
1272                         if (f->resume)
1273                                 f->resume(f);
1274                 }
1275
1276                 maxpower = cdev->config->bMaxPower;
1277
1278                 usb_gadget_vbus_draw(gadget, maxpower ?
1279                         (2 * maxpower) : CONFIG_USB_GADGET_VBUS_DRAW);
1280         }
1281
1282         cdev->suspended = 0;
1283 }
1284
1285 /*-------------------------------------------------------------------------*/
1286
1287 static struct usb_gadget_driver composite_driver = {
1288         .speed          = USB_SPEED_HIGH,
1289
1290         .unbind         = composite_unbind,
1291
1292         .setup          = composite_setup,
1293         .disconnect     = composite_disconnect,
1294
1295         .suspend        = composite_suspend,
1296         .resume         = composite_resume,
1297
1298         .driver = {
1299                 .owner          = THIS_MODULE,
1300         },
1301 };
1302
1303 /**
1304  * usb_composite_probe() - register a composite driver
1305  * @driver: the driver to register
1306  * @bind: the callback used to allocate resources that are shared across the
1307  *      whole device, such as string IDs, and add its configurations using
1308  *      @usb_add_config().  This may fail by returning a negative errno
1309  *      value; it should return zero on successful initialization.
1310  * Context: single threaded during gadget setup
1311  *
1312  * This function is used to register drivers using the composite driver
1313  * framework.  The return value is zero, or a negative errno value.
1314  * Those values normally come from the driver's @bind method, which does
1315  * all the work of setting up the driver to match the hardware.
1316  *
1317  * On successful return, the gadget is ready to respond to requests from
1318  * the host, unless one of its components invokes usb_gadget_disconnect()
1319  * while it was binding.  That would usually be done in order to wait for
1320  * some userspace participation.
1321  */
1322 int usb_composite_probe(struct usb_composite_driver *driver,
1323                                int (*bind)(struct usb_composite_dev *cdev))
1324 {
1325         if (!driver || !driver->dev || !bind || composite)
1326                 return -EINVAL;
1327
1328         if (!driver->name)
1329                 driver->name = "composite";
1330         if (!driver->iProduct)
1331                 driver->iProduct = driver->name;
1332         composite_driver.function =  (char *) driver->name;
1333         composite_driver.driver.name = driver->name;
1334         composite = driver;
1335         composite_gadget_bind = bind;
1336
1337         return usb_gadget_probe_driver(&composite_driver, composite_bind);
1338 }
1339
1340 /**
1341  * usb_composite_unregister() - unregister a composite driver
1342  * @driver: the driver to unregister
1343  *
1344  * This function is used to unregister drivers using the composite
1345  * driver framework.
1346  */
1347 void usb_composite_unregister(struct usb_composite_driver *driver)
1348 {
1349         if (composite != driver)
1350                 return;
1351         usb_gadget_unregister_driver(&composite_driver);
1352 }
1353
1354 /**
1355  * usb_composite_setup_continue() - Continue with the control transfer
1356  * @cdev: the composite device who's control transfer was kept waiting
1357  *
1358  * This function must be called by the USB function driver to continue
1359  * with the control transfer's data/status stage in case it had requested to
1360  * delay the data/status stages. A USB function's setup handler (e.g. set_alt())
1361  * can request the composite framework to delay the setup request's data/status
1362  * stages by returning USB_GADGET_DELAYED_STATUS.
1363  */
1364 void usb_composite_setup_continue(struct usb_composite_dev *cdev)
1365 {
1366         int                     value;
1367         struct usb_request      *req = cdev->req;
1368         unsigned long           flags;
1369
1370         DBG(cdev, "%s\n", __func__);
1371         spin_lock_irqsave(&cdev->lock, flags);
1372
1373         if (cdev->delayed_status == 0) {
1374                 WARN(cdev, "%s: Unexpected call\n", __func__);
1375
1376         } else if (--cdev->delayed_status == 0) {
1377                 DBG(cdev, "%s: Completing delayed status\n", __func__);
1378                 req->length = 0;
1379                 value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
1380                 if (value < 0) {
1381                         DBG(cdev, "ep_queue --> %d\n", value);
1382                         req->status = 0;
1383                         composite_setup_complete(cdev->gadget->ep0, req);
1384                 }
1385         }
1386         else{
1387             WARN(cdev, "%s: Unexpected delayed status 0x%x\n", __func__, cdev->delayed_status);
1388         }
1389
1390         spin_unlock_irqrestore(&cdev->lock, flags);
1391 }
1392