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