drivers/usb/class/cdc-wdm.c

   1 /*
   2  * cdc-wdm.c
   3  *
   4  * This driver supports USB CDC WCM Device Management.
   5  *
   6  * Copyright (c) 2007-2009 Oliver Neukum
   7  *
   8  * Some code taken from cdc-acm.c
   9  *
  10  * Released under the GPLv2.
  11  *
  12  * Many thanks to Carl Nordbeck
  13  */
  14 #include <linux/kernel.h>
  15 #include <linux/errno.h>
  16 #include <linux/slab.h>
  17 #include <linux/module.h>
  18 #include <linux/mutex.h>
  19 #include <linux/uaccess.h>
  20 #include <linux/bitops.h>
  21 #include <linux/poll.h>
  22 #include <linux/usb.h>
  23 #include <linux/usb/cdc.h>
  24 #include <asm/byteorder.h>
  25 #include <asm/unaligned.h>
  26 #include <linux/usb/cdc-wdm.h>
  27
  28 /*
  29  * Version Information
  30  */
  31 #define DRIVER_VERSION "v0.03"
  32 #define DRIVER_AUTHOR "Oliver Neukum"
  33 #define DRIVER_DESC "USB Abstract Control Model driver for USB WCM Device Management"
  34
  35 static const struct usb_device_id wdm_ids[] = {
  36         {
  37                 .match_flags = USB_DEVICE_ID_MATCH_INT_CLASS |
  38                                  USB_DEVICE_ID_MATCH_INT_SUBCLASS,
  39                 .bInterfaceClass = USB_CLASS_COMM,
  40                 .bInterfaceSubClass = USB_CDC_SUBCLASS_DMM
  41         },
  42         { }
  43 };
  44
  45 MODULE_DEVICE_TABLE (usb, wdm_ids);
  46
  47 #define WDM_MINOR_BASE  176
  48
  49
  50 #define WDM_IN_USE              1
  51 #define WDM_DISCONNECTING       2
  52 #define WDM_RESULT              3
  53 #define WDM_READ                4
  54 #define WDM_INT_STALL           5
  55 #define WDM_POLL_RUNNING        6
  56 #define WDM_RESPONDING          7
  57 #define WDM_SUSPENDING          8
  58 #define WDM_RESETTING           9
  59
  60 #define WDM_MAX                 16
  61
  62 /* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */
  63 #define WDM_DEFAULT_BUFSIZE     256
  64
  65 static DEFINE_MUTEX(wdm_mutex);
  66 static DEFINE_SPINLOCK(wdm_device_list_lock);
  67 static LIST_HEAD(wdm_device_list);
  68
  69 /* --- method tables --- */
  70
  71 struct wdm_device {
  72         u8                      *inbuf; /* buffer for response */
  73         u8                      *outbuf; /* buffer for command */
  74         u8                      *sbuf; /* buffer for status */
  75         u8                      *ubuf; /* buffer for copy to user space */
  76
  77         struct urb              *command;
  78         struct urb              *response;
  79         struct urb              *validity;
  80         struct usb_interface    *intf;
  81         struct usb_ctrlrequest  *orq;
  82         struct usb_ctrlrequest  *irq;
  83         spinlock_t              iuspin;
  84
  85         unsigned long           flags;
  86         u16                     bufsize;
  87         u16                     wMaxCommand;
  88         u16                     wMaxPacketSize;
  89         __le16                  inum;
  90         int                     reslength;
  91         int                     length;
  92         int                     read;
  93         int                     count;
  94         dma_addr_t              shandle;
  95         dma_addr_t              ihandle;
  96         struct mutex            wlock;
  97         struct mutex            rlock;
  98         wait_queue_head_t       wait;
  99         struct work_struct      rxwork;
 100         int                     werr;
 101         int                     rerr;
 102
 103         struct list_head        device_list;
 104         int                     (*manage_power)(struct usb_interface *, int);
 105 };
 106
 107 static struct usb_driver wdm_driver;
 108
 109 /* return intfdata if we own the interface, else look up intf in the list */
 110 static struct wdm_device *wdm_find_device(struct usb_interface *intf)
 111 {
 112         struct wdm_device *desc;
 113
 114         spin_lock(&wdm_device_list_lock);
 115         list_for_each_entry(desc, &wdm_device_list, device_list)
 116                 if (desc->intf == intf)
 117                         goto found;
 118         desc = NULL;
 119 found:
 120         spin_unlock(&wdm_device_list_lock);
 121
 122         return desc;
 123 }
 124
 125 static struct wdm_device *wdm_find_device_by_minor(int minor)
 126 {
 127         struct wdm_device *desc;
 128
 129         spin_lock(&wdm_device_list_lock);
 130         list_for_each_entry(desc, &wdm_device_list, device_list)
 131                 if (desc->intf->minor == minor)
 132                         goto found;
 133         desc = NULL;
 134 found:
 135         spin_unlock(&wdm_device_list_lock);
 136
 137         return desc;
 138 }
 139
 140 /* --- callbacks --- */
 141 static void wdm_out_callback(struct urb *urb)
 142 {
 143         struct wdm_device *desc;
 144         desc = urb->context;
 145         spin_lock(&desc->iuspin);
 146         desc->werr = urb->status;
 147         spin_unlock(&desc->iuspin);
 148         kfree(desc->outbuf);
 149         desc->outbuf = NULL;
 150         clear_bit(WDM_IN_USE, &desc->flags);
 151         wake_up(&desc->wait);
 152 }
 153
 154 static void wdm_in_callback(struct urb *urb)
 155 {
 156         struct wdm_device *desc = urb->context;
 157         int status = urb->status;
 158
 159         spin_lock(&desc->iuspin);
 160         clear_bit(WDM_RESPONDING, &desc->flags);
 161
 162         if (status) {
 163                 switch (status) {
 164                 case -ENOENT:
 165                         dev_dbg(&desc->intf->dev,
 166                                 "nonzero urb status received: -ENOENT");
 167                         goto skip_error;
 168                 case -ECONNRESET:
 169                         dev_dbg(&desc->intf->dev,
 170                                 "nonzero urb status received: -ECONNRESET");
 171                         goto skip_error;
 172                 case -ESHUTDOWN:
 173                         dev_dbg(&desc->intf->dev,
 174                                 "nonzero urb status received: -ESHUTDOWN");
 175                         goto skip_error;
 176                 case -EPIPE:
 177                         dev_err(&desc->intf->dev,
 178                                 "nonzero urb status received: -EPIPE\n");
 179                         break;
 180                 default:
 181                         dev_err(&desc->intf->dev,
 182                                 "Unexpected error %d\n", status);
 183                         break;
 184                 }
 185         }
 186
 187         desc->rerr = status;
 188         desc->reslength = urb->actual_length;
 189         memmove(desc->ubuf + desc->length, desc->inbuf, desc->reslength);
 190         desc->length += desc->reslength;
 191 skip_error:
 192         wake_up(&desc->wait);
 193
 194         set_bit(WDM_READ, &desc->flags);
 195         spin_unlock(&desc->iuspin);
 196 }
 197
 198 static void wdm_int_callback(struct urb *urb)
 199 {
 200         int rv = 0;
 201         int status = urb->status;
 202         struct wdm_device *desc;
 203         struct usb_cdc_notification *dr;
 204
 205         desc = urb->context;
 206         dr = (struct usb_cdc_notification *)desc->sbuf;
 207
 208         if (status) {
 209                 switch (status) {
 210                 case -ESHUTDOWN:
 211                 case -ENOENT:
 212                 case -ECONNRESET:
 213                         return; /* unplug */
 214                 case -EPIPE:
 215                         set_bit(WDM_INT_STALL, &desc->flags);
 216                         dev_err(&desc->intf->dev, "Stall on int endpoint\n");
 217                         goto sw; /* halt is cleared in work */
 218                 default:
 219                         dev_err(&desc->intf->dev,
 220                                 "nonzero urb status received: %d\n", status);
 221                         break;
 222                 }
 223         }
 224
 225         if (urb->actual_length < sizeof(struct usb_cdc_notification)) {
 226                 dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n",
 227                         urb->actual_length);
 228                 goto exit;
 229         }
 230
 231         switch (dr->bNotificationType) {
 232         case USB_CDC_NOTIFY_RESPONSE_AVAILABLE:
 233                 dev_dbg(&desc->intf->dev,
 234                         "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d",
 235                         dr->wIndex, dr->wLength);
 236                 break;
 237
 238         case USB_CDC_NOTIFY_NETWORK_CONNECTION:
 239
 240                 dev_dbg(&desc->intf->dev,
 241                         "NOTIFY_NETWORK_CONNECTION %s network",
 242                         dr->wValue ? "connected to" : "disconnected from");
 243                 goto exit;
 244         default:
 245                 clear_bit(WDM_POLL_RUNNING, &desc->flags);
 246                 dev_err(&desc->intf->dev,
 247                         "unknown notification %d received: index %d len %d\n",
 248                         dr->bNotificationType, dr->wIndex, dr->wLength);
 249                 goto exit;
 250         }
 251
 252         spin_lock(&desc->iuspin);
 253         clear_bit(WDM_READ, &desc->flags);
 254         set_bit(WDM_RESPONDING, &desc->flags);
 255         if (!test_bit(WDM_DISCONNECTING, &desc->flags)
 256                 && !test_bit(WDM_SUSPENDING, &desc->flags)) {
 257                 rv = usb_submit_urb(desc->response, GFP_ATOMIC);
 258                 dev_dbg(&desc->intf->dev, "%s: usb_submit_urb %d",
 259                         __func__, rv);
 260         }
 261         spin_unlock(&desc->iuspin);
 262         if (rv < 0) {
 263                 clear_bit(WDM_RESPONDING, &desc->flags);
 264                 if (rv == -EPERM)
 265                         return;
 266                 if (rv == -ENOMEM) {
 267 sw:
 268                         rv = schedule_work(&desc->rxwork);
 269                         if (rv)
 270                                 dev_err(&desc->intf->dev,
 271                                         "Cannot schedule work\n");
 272                 }
 273         }
 274 exit:
 275         rv = usb_submit_urb(urb, GFP_ATOMIC);
 276         if (rv)
 277                 dev_err(&desc->intf->dev,
 278                         "%s - usb_submit_urb failed with result %d\n",
 279                         __func__, rv);
 280
 281 }
 282
 283 static void kill_urbs(struct wdm_device *desc)
 284 {
 285         /* the order here is essential */
 286         usb_kill_urb(desc->command);
 287         usb_kill_urb(desc->validity);
 288         usb_kill_urb(desc->response);
 289 }
 290
 291 static void free_urbs(struct wdm_device *desc)
 292 {
 293         usb_free_urb(desc->validity);
 294         usb_free_urb(desc->response);
 295         usb_free_urb(desc->command);
 296 }
 297
 298 static void cleanup(struct wdm_device *desc)
 299 {
 300         kfree(desc->sbuf);
 301         kfree(desc->inbuf);
 302         kfree(desc->orq);
 303         kfree(desc->irq);
 304         kfree(desc->ubuf);
 305         free_urbs(desc);
 306         kfree(desc);
 307 }
 308
 309 static ssize_t wdm_write
 310 (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 311 {
 312         u8 *buf;
 313         int rv = -EMSGSIZE, r, we;
 314         struct wdm_device *desc = file->private_data;
 315         struct usb_ctrlrequest *req;
 316
 317         if (count > desc->wMaxCommand)
 318                 count = desc->wMaxCommand;
 319
 320         spin_lock_irq(&desc->iuspin);
 321         we = desc->werr;
 322         desc->werr = 0;
 323         spin_unlock_irq(&desc->iuspin);
 324         if (we < 0)
 325                 return -EIO;
 326
 327         buf = kmalloc(count, GFP_KERNEL);
 328         if (!buf) {
 329                 rv = -ENOMEM;
 330                 goto outnl;
 331         }
 332
 333         r = copy_from_user(buf, buffer, count);
 334         if (r > 0) {
 335                 kfree(buf);
 336                 rv = -EFAULT;
 337                 goto outnl;
 338         }
 339
 340         /* concurrent writes and disconnect */
 341         r = mutex_lock_interruptible(&desc->wlock);
 342         rv = -ERESTARTSYS;
 343         if (r) {
 344                 kfree(buf);
 345                 goto outnl;
 346         }
 347
 348         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 349                 kfree(buf);
 350                 rv = -ENODEV;
 351                 goto outnp;
 352         }
 353
 354         r = usb_autopm_get_interface(desc->intf);
 355         if (r < 0) {
 356                 kfree(buf);
 357                 rv = usb_translate_errors(r);
 358                 goto outnp;
 359         }
 360
 361         if (!(file->f_flags & O_NONBLOCK))
 362                 r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
 363                                                                 &desc->flags));
 364         else
 365                 if (test_bit(WDM_IN_USE, &desc->flags))
 366                         r = -EAGAIN;
 367
 368         if (test_bit(WDM_RESETTING, &desc->flags))
 369                 r = -EIO;
 370
 371         if (r < 0) {
 372                 kfree(buf);
 373                 rv = r;
 374                 goto out;
 375         }
 376
 377         req = desc->orq;
 378         usb_fill_control_urb(
 379                 desc->command,
 380                 interface_to_usbdev(desc->intf),
 381                 /* using common endpoint 0 */
 382                 usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
 383                 (unsigned char *)req,
 384                 buf,
 385                 count,
 386                 wdm_out_callback,
 387                 desc
 388         );
 389
 390         req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
 391                              USB_RECIP_INTERFACE);
 392         req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
 393         req->wValue = 0;
 394         req->wIndex = desc->inum;
 395         req->wLength = cpu_to_le16(count);
 396         set_bit(WDM_IN_USE, &desc->flags);
 397         desc->outbuf = buf;
 398
 399         rv = usb_submit_urb(desc->command, GFP_KERNEL);
 400         if (rv < 0) {
 401                 kfree(buf);
 402                 desc->outbuf = NULL;
 403                 clear_bit(WDM_IN_USE, &desc->flags);
 404                 dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
 405                 rv = usb_translate_errors(rv);
 406         } else {
 407                 dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d",
 408                         req->wIndex);
 409         }
 410 out:
 411         usb_autopm_put_interface(desc->intf);
 412 outnp:
 413         mutex_unlock(&desc->wlock);
 414 outnl:
 415         return rv < 0 ? rv : count;
 416 }
 417
 418 static ssize_t wdm_read
 419 (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 420 {
 421         int rv, cntr;
 422         int i = 0;
 423         struct wdm_device *desc = file->private_data;
 424
 425
 426         rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
 427         if (rv < 0)
 428                 return -ERESTARTSYS;
 429
 430         cntr = ACCESS_ONCE(desc->length);
 431         if (cntr == 0) {
 432                 desc->read = 0;
 433 retry:
 434                 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 435                         rv = -ENODEV;
 436                         goto err;
 437                 }
 438                 i++;
 439                 if (file->f_flags & O_NONBLOCK) {
 440                         if (!test_bit(WDM_READ, &desc->flags)) {
 441                                 rv = cntr ? cntr : -EAGAIN;
 442                                 goto err;
 443                         }
 444                         rv = 0;
 445                 } else {
 446                         rv = wait_event_interruptible(desc->wait,
 447                                 test_bit(WDM_READ, &desc->flags));
 448                 }
 449
 450                 /* may have happened while we slept */
 451                 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 452                         rv = -ENODEV;
 453                         goto err;
 454                 }
 455                 if (test_bit(WDM_RESETTING, &desc->flags)) {
 456                         rv = -EIO;
 457                         goto err;
 458                 }
 459                 usb_mark_last_busy(interface_to_usbdev(desc->intf));
 460                 if (rv < 0) {
 461                         rv = -ERESTARTSYS;
 462                         goto err;
 463                 }
 464
 465                 spin_lock_irq(&desc->iuspin);
 466
 467                 if (desc->rerr) { /* read completed, error happened */
 468                         desc->rerr = 0;
 469                         spin_unlock_irq(&desc->iuspin);
 470                         rv = -EIO;
 471                         goto err;
 472                 }
 473                 /*
 474                  * recheck whether we've lost the race
 475                  * against the completion handler
 476                  */
 477                 if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */
 478                         spin_unlock_irq(&desc->iuspin);
 479                         goto retry;
 480                 }
 481                 if (!desc->reslength) { /* zero length read */
 482                         dev_dbg(&desc->intf->dev, "%s: zero length - clearing WDM_READ\n", __func__);
 483                         clear_bit(WDM_READ, &desc->flags);
 484                         spin_unlock_irq(&desc->iuspin);
 485                         goto retry;
 486                 }
 487                 cntr = desc->length;
 488                 spin_unlock_irq(&desc->iuspin);
 489         }
 490
 491         if (cntr > count)
 492                 cntr = count;
 493         rv = copy_to_user(buffer, desc->ubuf, cntr);
 494         if (rv > 0) {
 495                 rv = -EFAULT;
 496                 goto err;
 497         }
 498
 499         spin_lock_irq(&desc->iuspin);
 500
 501         for (i = 0; i < desc->length - cntr; i++)
 502                 desc->ubuf[i] = desc->ubuf[i + cntr];
 503
 504         desc->length -= cntr;
 505         /* in case we had outstanding data */
 506         if (!desc->length)
 507                 clear_bit(WDM_READ, &desc->flags);
 508
 509         spin_unlock_irq(&desc->iuspin);
 510
 511         rv = cntr;
 512
 513 err:
 514         mutex_unlock(&desc->rlock);
 515         return rv;
 516 }
 517
 518 static int wdm_flush(struct file *file, fl_owner_t id)
 519 {
 520         struct wdm_device *desc = file->private_data;
 521
 522         wait_event(desc->wait, !test_bit(WDM_IN_USE, &desc->flags));
 523
 524         /* cannot dereference desc->intf if WDM_DISCONNECTING */
 525         if (desc->werr < 0 && !test_bit(WDM_DISCONNECTING, &desc->flags))
 526                 dev_err(&desc->intf->dev, "Error in flush path: %d\n",
 527                         desc->werr);
 528
 529         return usb_translate_errors(desc->werr);
 530 }
 531
 532 static unsigned int wdm_poll(struct file *file, struct poll_table_struct *wait)
 533 {
 534         struct wdm_device *desc = file->private_data;
 535         unsigned long flags;
 536         unsigned int mask = 0;
 537
 538         spin_lock_irqsave(&desc->iuspin, flags);
 539         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 540                 mask = POLLHUP | POLLERR;
 541                 spin_unlock_irqrestore(&desc->iuspin, flags);
 542                 goto desc_out;
 543         }
 544         if (test_bit(WDM_READ, &desc->flags))
 545                 mask = POLLIN | POLLRDNORM;
 546         if (desc->rerr || desc->werr)
 547                 mask |= POLLERR;
 548         if (!test_bit(WDM_IN_USE, &desc->flags))
 549                 mask |= POLLOUT | POLLWRNORM;
 550         spin_unlock_irqrestore(&desc->iuspin, flags);
 551
 552         poll_wait(file, &desc->wait, wait);
 553
 554 desc_out:
 555         return mask;
 556 }
 557
 558 static int wdm_open(struct inode *inode, struct file *file)
 559 {
 560         int minor = iminor(inode);
 561         int rv = -ENODEV;
 562         struct usb_interface *intf;
 563         struct wdm_device *desc;
 564
 565         mutex_lock(&wdm_mutex);
 566         desc = wdm_find_device_by_minor(minor);
 567         if (!desc)
 568                 goto out;
 569
 570         intf = desc->intf;
 571         if (test_bit(WDM_DISCONNECTING, &desc->flags))
 572                 goto out;
 573         file->private_data = desc;
 574
 575         rv = usb_autopm_get_interface(desc->intf);
 576         if (rv < 0) {
 577                 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
 578                 goto out;
 579         }
 580
 581         /* using write lock to protect desc->count */
 582         mutex_lock(&desc->wlock);
 583         if (!desc->count++) {
 584                 desc->werr = 0;
 585                 desc->rerr = 0;
 586                 rv = usb_submit_urb(desc->validity, GFP_KERNEL);
 587                 if (rv < 0) {
 588                         desc->count--;
 589                         dev_err(&desc->intf->dev,
 590                                 "Error submitting int urb - %d\n", rv);
 591                         rv = usb_translate_errors(rv);
 592                 }
 593         } else {
 594                 rv = 0;
 595         }
 596         mutex_unlock(&desc->wlock);
 597         if (desc->count == 1)
 598                 desc->manage_power(intf, 1);
 599         usb_autopm_put_interface(desc->intf);
 600 out:
 601         mutex_unlock(&wdm_mutex);
 602         return rv;
 603 }
 604
 605 static int wdm_release(struct inode *inode, struct file *file)
 606 {
 607         struct wdm_device *desc = file->private_data;
 608
 609         mutex_lock(&wdm_mutex);
 610
 611         /* using write lock to protect desc->count */
 612         mutex_lock(&desc->wlock);
 613         desc->count--;
 614         mutex_unlock(&desc->wlock);
 615
 616         if (!desc->count) {
 617                 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
 618                         dev_dbg(&desc->intf->dev, "wdm_release: cleanup");
 619                         kill_urbs(desc);
 620                         desc->manage_power(desc->intf, 0);
 621                 } else {
 622                         /* must avoid dev_printk here as desc->intf is invalid */
 623                         pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
 624                         cleanup(desc);
 625                 }
 626         }
 627         mutex_unlock(&wdm_mutex);
 628         return 0;
 629 }
 630
 631 static const struct file_operations wdm_fops = {
 632         .owner =        THIS_MODULE,
 633         .read =         wdm_read,
 634         .write =        wdm_write,
 635         .open =         wdm_open,
 636         .flush =        wdm_flush,
 637         .release =      wdm_release,
 638         .poll =         wdm_poll,
 639         .llseek =       noop_llseek,
 640 };
 641
 642 static struct usb_class_driver wdm_class = {
 643         .name =         "cdc-wdm%d",
 644         .fops =         &wdm_fops,
 645         .minor_base =   WDM_MINOR_BASE,
 646 };
 647
 648 /* --- error handling --- */
 649 static void wdm_rxwork(struct work_struct *work)
 650 {
 651         struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
 652         unsigned long flags;
 653         int rv;
 654
 655         spin_lock_irqsave(&desc->iuspin, flags);
 656         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 657                 spin_unlock_irqrestore(&desc->iuspin, flags);
 658         } else {
 659                 spin_unlock_irqrestore(&desc->iuspin, flags);
 660                 rv = usb_submit_urb(desc->response, GFP_KERNEL);
 661                 if (rv < 0 && rv != -EPERM) {
 662                         spin_lock_irqsave(&desc->iuspin, flags);
 663                         if (!test_bit(WDM_DISCONNECTING, &desc->flags))
 664                                 schedule_work(&desc->rxwork);
 665                         spin_unlock_irqrestore(&desc->iuspin, flags);
 666                 }
 667         }
 668 }
 669
 670 /* --- hotplug --- */
 671
 672 static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
 673                 u16 bufsize, int (*manage_power)(struct usb_interface *, int))
 674 {
 675         int rv = -ENOMEM;
 676         struct wdm_device *desc;
 677
 678         desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
 679         if (!desc)
 680                 goto out;
 681         INIT_LIST_HEAD(&desc->device_list);
 682         mutex_init(&desc->rlock);
 683         mutex_init(&desc->wlock);
 684         spin_lock_init(&desc->iuspin);
 685         init_waitqueue_head(&desc->wait);
 686         desc->wMaxCommand = bufsize;
 687         /* this will be expanded and needed in hardware endianness */
 688         desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
 689         desc->intf = intf;
 690         INIT_WORK(&desc->rxwork, wdm_rxwork);
 691
 692         rv = -EINVAL;
 693         if (!usb_endpoint_is_int_in(ep))
 694                 goto err;
 695
 696         desc->wMaxPacketSize = usb_endpoint_maxp(ep);
 697
 698         desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
 699         if (!desc->orq)
 700                 goto err;
 701         desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
 702         if (!desc->irq)
 703                 goto err;
 704
 705         desc->validity = usb_alloc_urb(0, GFP_KERNEL);
 706         if (!desc->validity)
 707                 goto err;
 708
 709         desc->response = usb_alloc_urb(0, GFP_KERNEL);
 710         if (!desc->response)
 711                 goto err;
 712
 713         desc->command = usb_alloc_urb(0, GFP_KERNEL);
 714         if (!desc->command)
 715                 goto err;
 716
 717         desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
 718         if (!desc->ubuf)
 719                 goto err;
 720
 721         desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);
 722         if (!desc->sbuf)
 723                 goto err;
 724
 725         desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
 726         if (!desc->inbuf)
 727                 goto err;
 728
 729         usb_fill_int_urb(
 730                 desc->validity,
 731                 interface_to_usbdev(intf),
 732                 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
 733                 desc->sbuf,
 734                 desc->wMaxPacketSize,
 735                 wdm_int_callback,
 736                 desc,
 737                 ep->bInterval
 738         );
 739
 740         desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
 741         desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
 742         desc->irq->wValue = 0;
 743         desc->irq->wIndex = desc->inum;
 744         desc->irq->wLength = cpu_to_le16(desc->wMaxCommand);
 745
 746         usb_fill_control_urb(
 747                 desc->response,
 748                 interface_to_usbdev(intf),
 749                 /* using common endpoint 0 */
 750                 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
 751                 (unsigned char *)desc->irq,
 752                 desc->inbuf,
 753                 desc->wMaxCommand,
 754                 wdm_in_callback,
 755                 desc
 756         );
 757
 758         desc->manage_power = manage_power;
 759
 760         spin_lock(&wdm_device_list_lock);
 761         list_add(&desc->device_list, &wdm_device_list);
 762         spin_unlock(&wdm_device_list_lock);
 763
 764         rv = usb_register_dev(intf, &wdm_class);
 765         if (rv < 0)
 766                 goto err;
 767         else
 768                 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev));
 769 out:
 770         return rv;
 771 err:
 772         spin_lock(&wdm_device_list_lock);
 773         list_del(&desc->device_list);
 774         spin_unlock(&wdm_device_list_lock);
 775         cleanup(desc);
 776         return rv;
 777 }
 778
 779 static int wdm_manage_power(struct usb_interface *intf, int on)
 780 {
 781         /* need autopm_get/put here to ensure the usbcore sees the new value */
 782         int rv = usb_autopm_get_interface(intf);
 783         if (rv < 0)
 784                 goto err;
 785
 786         intf->needs_remote_wakeup = on;
 787         usb_autopm_put_interface(intf);
 788 err:
 789         return rv;
 790 }
 791
 792 static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
 793 {
 794         int rv = -EINVAL;
 795         struct usb_host_interface *iface;
 796         struct usb_endpoint_descriptor *ep;
 797         struct usb_cdc_dmm_desc *dmhd;
 798         u8 *buffer = intf->altsetting->extra;
 799         int buflen = intf->altsetting->extralen;
 800         u16 maxcom = WDM_DEFAULT_BUFSIZE;
 801
 802         if (!buffer)
 803                 goto err;
 804         while (buflen > 2) {
 805                 if (buffer[1] != USB_DT_CS_INTERFACE) {
 806                         dev_err(&intf->dev, "skipping garbage\n");
 807                         goto next_desc;
 808                 }
 809
 810                 switch (buffer[2]) {
 811                 case USB_CDC_HEADER_TYPE:
 812                         break;
 813                 case USB_CDC_DMM_TYPE:
 814                         dmhd = (struct usb_cdc_dmm_desc *)buffer;
 815                         maxcom = le16_to_cpu(dmhd->wMaxCommand);
 816                         dev_dbg(&intf->dev,
 817                                 "Finding maximum buffer length: %d", maxcom);
 818                         break;
 819                 default:
 820                         dev_err(&intf->dev,
 821                                 "Ignoring extra header, type %d, length %d\n",
 822                                 buffer[2], buffer[0]);
 823                         break;
 824                 }
 825 next_desc:
 826                 buflen -= buffer[0];
 827                 buffer += buffer[0];
 828         }
 829
 830         iface = intf->cur_altsetting;
 831         if (iface->desc.bNumEndpoints != 1)
 832                 goto err;
 833         ep = &iface->endpoint[0].desc;
 834
 835         rv = wdm_create(intf, ep, maxcom, &wdm_manage_power);
 836
 837 err:
 838         return rv;
 839 }
 840
 841 /**
 842  * usb_cdc_wdm_register - register a WDM subdriver
 843  * @intf: usb interface the subdriver will associate with
 844  * @ep: interrupt endpoint to monitor for notifications
 845  * @bufsize: maximum message size to support for read/write
 846  *
 847  * Create WDM usb class character device and associate it with intf
 848  * without binding, allowing another driver to manage the interface.
 849  *
 850  * The subdriver will manage the given interrupt endpoint exclusively
 851  * and will issue control requests referring to the given intf. It
 852  * will otherwise avoid interferring, and in particular not do
 853  * usb_set_intfdata/usb_get_intfdata on intf.
 854  *
 855  * The return value is a pointer to the subdriver's struct usb_driver.
 856  * The registering driver is responsible for calling this subdriver's
 857  * disconnect, suspend, resume, pre_reset and post_reset methods from
 858  * its own.
 859  */
 860 struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,
 861                                         struct usb_endpoint_descriptor *ep,
 862                                         int bufsize,
 863                                         int (*manage_power)(struct usb_interface *, int))
 864 {
 865         int rv = -EINVAL;
 866
 867         rv = wdm_create(intf, ep, bufsize, manage_power);
 868         if (rv < 0)
 869                 goto err;
 870
 871         return &wdm_driver;
 872 err:
 873         return ERR_PTR(rv);
 874 }
 875 EXPORT_SYMBOL(usb_cdc_wdm_register);
 876
 877 static void wdm_disconnect(struct usb_interface *intf)
 878 {
 879         struct wdm_device *desc;
 880         unsigned long flags;
 881
 882         usb_deregister_dev(intf, &wdm_class);
 883         desc = wdm_find_device(intf);
 884         mutex_lock(&wdm_mutex);
 885
 886         /* the spinlock makes sure no new urbs are generated in the callbacks */
 887         spin_lock_irqsave(&desc->iuspin, flags);
 888         set_bit(WDM_DISCONNECTING, &desc->flags);
 889         set_bit(WDM_READ, &desc->flags);
 890         /* to terminate pending flushes */
 891         clear_bit(WDM_IN_USE, &desc->flags);
 892         spin_unlock_irqrestore(&desc->iuspin, flags);
 893         wake_up_all(&desc->wait);
 894         mutex_lock(&desc->rlock);
 895         mutex_lock(&desc->wlock);
 896         kill_urbs(desc);
 897         cancel_work_sync(&desc->rxwork);
 898         mutex_unlock(&desc->wlock);
 899         mutex_unlock(&desc->rlock);
 900
 901         /* the desc->intf pointer used as list key is now invalid */
 902         spin_lock(&wdm_device_list_lock);
 903         list_del(&desc->device_list);
 904         spin_unlock(&wdm_device_list_lock);
 905
 906         if (!desc->count)
 907                 cleanup(desc);
 908         else
 909                 dev_dbg(&intf->dev, "%s: %d open files - postponing cleanup\n", __func__, desc->count);
 910         mutex_unlock(&wdm_mutex);
 911 }
 912
 913 #ifdef CONFIG_PM
 914 static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
 915 {
 916         struct wdm_device *desc = wdm_find_device(intf);
 917         int rv = 0;
 918
 919         dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
 920
 921         /* if this is an autosuspend the caller does the locking */
 922         if (!PMSG_IS_AUTO(message)) {
 923                 mutex_lock(&desc->rlock);
 924                 mutex_lock(&desc->wlock);
 925         }
 926         spin_lock_irq(&desc->iuspin);
 927
 928         if (PMSG_IS_AUTO(message) &&
 929                         (test_bit(WDM_IN_USE, &desc->flags)
 930                         || test_bit(WDM_RESPONDING, &desc->flags))) {
 931                 spin_unlock_irq(&desc->iuspin);
 932                 rv = -EBUSY;
 933         } else {
 934
 935                 set_bit(WDM_SUSPENDING, &desc->flags);
 936                 spin_unlock_irq(&desc->iuspin);
 937                 /* callback submits work - order is essential */
 938                 kill_urbs(desc);
 939                 cancel_work_sync(&desc->rxwork);
 940         }
 941         if (!PMSG_IS_AUTO(message)) {
 942                 mutex_unlock(&desc->wlock);
 943                 mutex_unlock(&desc->rlock);
 944         }
 945
 946         return rv;
 947 }
 948 #endif
 949
 950 static int recover_from_urb_loss(struct wdm_device *desc)
 951 {
 952         int rv = 0;
 953
 954         if (desc->count) {
 955                 rv = usb_submit_urb(desc->validity, GFP_NOIO);
 956                 if (rv < 0)
 957                         dev_err(&desc->intf->dev,
 958                                 "Error resume submitting int urb - %d\n", rv);
 959         }
 960         return rv;
 961 }
 962
 963 #ifdef CONFIG_PM
 964 static int wdm_resume(struct usb_interface *intf)
 965 {
 966         struct wdm_device *desc = wdm_find_device(intf);
 967         int rv;
 968
 969         dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
 970
 971         clear_bit(WDM_SUSPENDING, &desc->flags);
 972         rv = recover_from_urb_loss(desc);
 973
 974         return rv;
 975 }
 976 #endif
 977
 978 static int wdm_pre_reset(struct usb_interface *intf)
 979 {
 980         struct wdm_device *desc = wdm_find_device(intf);
 981
 982         /*
 983          * we notify everybody using poll of
 984          * an exceptional situation
 985          * must be done before recovery lest a spontaneous
 986          * message from the device is lost
 987          */
 988         spin_lock_irq(&desc->iuspin);
 989         set_bit(WDM_RESETTING, &desc->flags);   /* inform read/write */
 990         set_bit(WDM_READ, &desc->flags);        /* unblock read */
 991         clear_bit(WDM_IN_USE, &desc->flags);    /* unblock write */
 992         desc->rerr = -EINTR;
 993         spin_unlock_irq(&desc->iuspin);
 994         wake_up_all(&desc->wait);
 995         mutex_lock(&desc->rlock);
 996         mutex_lock(&desc->wlock);
 997         kill_urbs(desc);
 998         cancel_work_sync(&desc->rxwork);
 999         return 0;
1000 }
1001
1002 static int wdm_post_reset(struct usb_interface *intf)
1003 {
1004         struct wdm_device *desc = wdm_find_device(intf);
1005         int rv;
1006
1007         clear_bit(WDM_RESETTING, &desc->flags);
1008         rv = recover_from_urb_loss(desc);
1009         mutex_unlock(&desc->wlock);
1010         mutex_unlock(&desc->rlock);
1011         return 0;
1012 }
1013
1014 static struct usb_driver wdm_driver = {
1015         .name =         "cdc_wdm",
1016         .probe =        wdm_probe,
1017         .disconnect =   wdm_disconnect,
1018 #ifdef CONFIG_PM
1019         .suspend =      wdm_suspend,
1020         .resume =       wdm_resume,
1021         .reset_resume = wdm_resume,
1022 #endif
1023         .pre_reset =    wdm_pre_reset,
1024         .post_reset =   wdm_post_reset,
1025         .id_table =     wdm_ids,
1026         .supports_autosuspend = 1,
1027         .disable_hub_initiated_lpm = 1,
1028 };
1029
1030 module_usb_driver(wdm_driver);
1031
1032 MODULE_AUTHOR(DRIVER_AUTHOR);
1033 MODULE_DESCRIPTION(DRIVER_DESC);
1034 MODULE_LICENSE("GPL");