drivers/usb/class/cdc-wdm.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * cdc-wdm.c
   4  *
   5  * This driver supports USB CDC WCM Device Management.
   6  *
   7  * Copyright (c) 2007-2009 Oliver Neukum
   8  *
   9  * Some code taken from cdc-acm.c
  10  *
  11  * Released under the GPLv2.
  12  *
  13  * Many thanks to Carl Nordbeck
  14  */
  15 #include <linux/kernel.h>
  16 #include <linux/errno.h>
  17 #include <linux/ioctl.h>
  18 #include <linux/slab.h>
  19 #include <linux/module.h>
  20 #include <linux/mutex.h>
  21 #include <linux/uaccess.h>
  22 #include <linux/bitops.h>
  23 #include <linux/poll.h>
  24 #include <linux/skbuff.h>
  25 #include <linux/usb.h>
  26 #include <linux/usb/cdc.h>
  27 #include <linux/wwan.h>
  28 #include <asm/byteorder.h>
  29 #include <asm/unaligned.h>
  30 #include <linux/usb/cdc-wdm.h>
  31
  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 #define WDM_OVERFLOW            10
  60 #define WDM_WWAN_IN_USE         11
  61
  62 #define WDM_MAX                 16
  63
  64 /* we cannot wait forever at flush() */
  65 #define WDM_FLUSH_TIMEOUT       (30 * HZ)
  66
  67 /* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */
  68 #define WDM_DEFAULT_BUFSIZE     256
  69
  70 static DEFINE_MUTEX(wdm_mutex);
  71 static DEFINE_SPINLOCK(wdm_device_list_lock);
  72 static LIST_HEAD(wdm_device_list);
  73
  74 /* --- method tables --- */
  75
  76 struct wdm_device {
  77         u8                      *inbuf; /* buffer for response */
  78         u8                      *outbuf; /* buffer for command */
  79         u8                      *sbuf; /* buffer for status */
  80         u8                      *ubuf; /* buffer for copy to user space */
  81
  82         struct urb              *command;
  83         struct urb              *response;
  84         struct urb              *validity;
  85         struct usb_interface    *intf;
  86         struct usb_ctrlrequest  *orq;
  87         struct usb_ctrlrequest  *irq;
  88         spinlock_t              iuspin;
  89
  90         unsigned long           flags;
  91         u16                     bufsize;
  92         u16                     wMaxCommand;
  93         u16                     wMaxPacketSize;
  94         __le16                  inum;
  95         int                     reslength;
  96         int                     length;
  97         int                     read;
  98         int                     count;
  99         dma_addr_t              shandle;
 100         dma_addr_t              ihandle;
 101         struct mutex            wlock;
 102         struct mutex            rlock;
 103         wait_queue_head_t       wait;
 104         struct work_struct      rxwork;
 105         struct work_struct      service_outs_intr;
 106         int                     werr;
 107         int                     rerr;
 108         int                     resp_count;
 109
 110         struct list_head        device_list;
 111         int                     (*manage_power)(struct usb_interface *, int);
 112
 113         enum wwan_port_type     wwanp_type;
 114         struct wwan_port        *wwanp;
 115 };
 116
 117 static struct usb_driver wdm_driver;
 118
 119 /* return intfdata if we own the interface, else look up intf in the list */
 120 static struct wdm_device *wdm_find_device(struct usb_interface *intf)
 121 {
 122         struct wdm_device *desc;
 123
 124         spin_lock(&wdm_device_list_lock);
 125         list_for_each_entry(desc, &wdm_device_list, device_list)
 126                 if (desc->intf == intf)
 127                         goto found;
 128         desc = NULL;
 129 found:
 130         spin_unlock(&wdm_device_list_lock);
 131
 132         return desc;
 133 }
 134
 135 static struct wdm_device *wdm_find_device_by_minor(int minor)
 136 {
 137         struct wdm_device *desc;
 138
 139         spin_lock(&wdm_device_list_lock);
 140         list_for_each_entry(desc, &wdm_device_list, device_list)
 141                 if (desc->intf->minor == minor)
 142                         goto found;
 143         desc = NULL;
 144 found:
 145         spin_unlock(&wdm_device_list_lock);
 146
 147         return desc;
 148 }
 149
 150 /* --- callbacks --- */
 151 static void wdm_out_callback(struct urb *urb)
 152 {
 153         struct wdm_device *desc;
 154         unsigned long flags;
 155
 156         desc = urb->context;
 157         spin_lock_irqsave(&desc->iuspin, flags);
 158         desc->werr = urb->status;
 159         spin_unlock_irqrestore(&desc->iuspin, flags);
 160         kfree(desc->outbuf);
 161         desc->outbuf = NULL;
 162         clear_bit(WDM_IN_USE, &desc->flags);
 163         wake_up_all(&desc->wait);
 164 }
 165
 166 static void wdm_wwan_rx(struct wdm_device *desc, int length);
 167
 168 static void wdm_in_callback(struct urb *urb)
 169 {
 170         unsigned long flags;
 171         struct wdm_device *desc = urb->context;
 172         int status = urb->status;
 173         int length = urb->actual_length;
 174
 175         spin_lock_irqsave(&desc->iuspin, flags);
 176         clear_bit(WDM_RESPONDING, &desc->flags);
 177
 178         if (status) {
 179                 switch (status) {
 180                 case -ENOENT:
 181                         dev_dbg(&desc->intf->dev,
 182                                 "nonzero urb status received: -ENOENT\n");
 183                         goto skip_error;
 184                 case -ECONNRESET:
 185                         dev_dbg(&desc->intf->dev,
 186                                 "nonzero urb status received: -ECONNRESET\n");
 187                         goto skip_error;
 188                 case -ESHUTDOWN:
 189                         dev_dbg(&desc->intf->dev,
 190                                 "nonzero urb status received: -ESHUTDOWN\n");
 191                         goto skip_error;
 192                 case -EPIPE:
 193                         dev_err(&desc->intf->dev,
 194                                 "nonzero urb status received: -EPIPE\n");
 195                         break;
 196                 default:
 197                         dev_err(&desc->intf->dev,
 198                                 "Unexpected error %d\n", status);
 199                         break;
 200                 }
 201         }
 202
 203         if (test_bit(WDM_WWAN_IN_USE, &desc->flags)) {
 204                 wdm_wwan_rx(desc, length);
 205                 goto out;
 206         }
 207
 208         /*
 209          * only set a new error if there is no previous error.
 210          * Errors are only cleared during read/open
 211          * Avoid propagating -EPIPE (stall) to userspace since it is
 212          * better handled as an empty read
 213          */
 214         if (desc->rerr == 0 && status != -EPIPE)
 215                 desc->rerr = status;
 216
 217         if (length + desc->length > desc->wMaxCommand) {
 218                 /* The buffer would overflow */
 219                 set_bit(WDM_OVERFLOW, &desc->flags);
 220         } else {
 221                 /* we may already be in overflow */
 222                 if (!test_bit(WDM_OVERFLOW, &desc->flags)) {
 223                         memmove(desc->ubuf + desc->length, desc->inbuf, length);
 224                         desc->length += length;
 225                         desc->reslength = length;
 226                 }
 227         }
 228 skip_error:
 229
 230         if (desc->rerr) {
 231                 /*
 232                  * Since there was an error, userspace may decide to not read
 233                  * any data after poll'ing.
 234                  * We should respond to further attempts from the device to send
 235                  * data, so that we can get unstuck.
 236                  */
 237                 schedule_work(&desc->service_outs_intr);
 238         } else {
 239                 set_bit(WDM_READ, &desc->flags);
 240                 wake_up(&desc->wait);
 241         }
 242 out:
 243         spin_unlock_irqrestore(&desc->iuspin, flags);
 244 }
 245
 246 static void wdm_int_callback(struct urb *urb)
 247 {
 248         unsigned long flags;
 249         int rv = 0;
 250         int responding;
 251         int status = urb->status;
 252         struct wdm_device *desc;
 253         struct usb_cdc_notification *dr;
 254
 255         desc = urb->context;
 256         dr = (struct usb_cdc_notification *)desc->sbuf;
 257
 258         if (status) {
 259                 switch (status) {
 260                 case -ESHUTDOWN:
 261                 case -ENOENT:
 262                 case -ECONNRESET:
 263                         return; /* unplug */
 264                 case -EPIPE:
 265                         set_bit(WDM_INT_STALL, &desc->flags);
 266                         dev_err(&desc->intf->dev, "Stall on int endpoint\n");
 267                         goto sw; /* halt is cleared in work */
 268                 default:
 269                         dev_err(&desc->intf->dev,
 270                                 "nonzero urb status received: %d\n", status);
 271                         break;
 272                 }
 273         }
 274
 275         if (urb->actual_length < sizeof(struct usb_cdc_notification)) {
 276                 dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n",
 277                         urb->actual_length);
 278                 goto exit;
 279         }
 280
 281         switch (dr->bNotificationType) {
 282         case USB_CDC_NOTIFY_RESPONSE_AVAILABLE:
 283                 dev_dbg(&desc->intf->dev,
 284                         "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d\n",
 285                         le16_to_cpu(dr->wIndex), le16_to_cpu(dr->wLength));
 286                 break;
 287
 288         case USB_CDC_NOTIFY_NETWORK_CONNECTION:
 289
 290                 dev_dbg(&desc->intf->dev,
 291                         "NOTIFY_NETWORK_CONNECTION %s network\n",
 292                         dr->wValue ? "connected to" : "disconnected from");
 293                 goto exit;
 294         case USB_CDC_NOTIFY_SPEED_CHANGE:
 295                 dev_dbg(&desc->intf->dev, "SPEED_CHANGE received (len %u)\n",
 296                         urb->actual_length);
 297                 goto exit;
 298         default:
 299                 clear_bit(WDM_POLL_RUNNING, &desc->flags);
 300                 dev_err(&desc->intf->dev,
 301                         "unknown notification %d received: index %d len %d\n",
 302                         dr->bNotificationType,
 303                         le16_to_cpu(dr->wIndex),
 304                         le16_to_cpu(dr->wLength));
 305                 goto exit;
 306         }
 307
 308         spin_lock_irqsave(&desc->iuspin, flags);
 309         responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
 310         if (!desc->resp_count++ && !responding
 311                 && !test_bit(WDM_DISCONNECTING, &desc->flags)
 312                 && !test_bit(WDM_SUSPENDING, &desc->flags)) {
 313                 rv = usb_submit_urb(desc->response, GFP_ATOMIC);
 314                 dev_dbg(&desc->intf->dev, "submit response URB %d\n", rv);
 315         }
 316         spin_unlock_irqrestore(&desc->iuspin, flags);
 317         if (rv < 0) {
 318                 clear_bit(WDM_RESPONDING, &desc->flags);
 319                 if (rv == -EPERM)
 320                         return;
 321                 if (rv == -ENOMEM) {
 322 sw:
 323                         rv = schedule_work(&desc->rxwork);
 324                         if (rv)
 325                                 dev_err(&desc->intf->dev,
 326                                         "Cannot schedule work\n");
 327                 }
 328         }
 329 exit:
 330         rv = usb_submit_urb(urb, GFP_ATOMIC);
 331         if (rv)
 332                 dev_err(&desc->intf->dev,
 333                         "%s - usb_submit_urb failed with result %d\n",
 334                         __func__, rv);
 335
 336 }
 337
 338 static void poison_urbs(struct wdm_device *desc)
 339 {
 340         /* the order here is essential */
 341         usb_poison_urb(desc->command);
 342         usb_poison_urb(desc->validity);
 343         usb_poison_urb(desc->response);
 344 }
 345
 346 static void unpoison_urbs(struct wdm_device *desc)
 347 {
 348         /*
 349          *  the order here is not essential
 350          *  it is symmetrical just to be nice
 351          */
 352         usb_unpoison_urb(desc->response);
 353         usb_unpoison_urb(desc->validity);
 354         usb_unpoison_urb(desc->command);
 355 }
 356
 357 static void free_urbs(struct wdm_device *desc)
 358 {
 359         usb_free_urb(desc->validity);
 360         usb_free_urb(desc->response);
 361         usb_free_urb(desc->command);
 362 }
 363
 364 static void cleanup(struct wdm_device *desc)
 365 {
 366         kfree(desc->sbuf);
 367         kfree(desc->inbuf);
 368         kfree(desc->orq);
 369         kfree(desc->irq);
 370         kfree(desc->ubuf);
 371         free_urbs(desc);
 372         kfree(desc);
 373 }
 374
 375 static ssize_t wdm_write
 376 (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 377 {
 378         u8 *buf;
 379         int rv = -EMSGSIZE, r, we;
 380         struct wdm_device *desc = file->private_data;
 381         struct usb_ctrlrequest *req;
 382
 383         if (count > desc->wMaxCommand)
 384                 count = desc->wMaxCommand;
 385
 386         spin_lock_irq(&desc->iuspin);
 387         we = desc->werr;
 388         desc->werr = 0;
 389         spin_unlock_irq(&desc->iuspin);
 390         if (we < 0)
 391                 return usb_translate_errors(we);
 392
 393         buf = memdup_user(buffer, count);
 394         if (IS_ERR(buf))
 395                 return PTR_ERR(buf);
 396
 397         /* concurrent writes and disconnect */
 398         r = mutex_lock_interruptible(&desc->wlock);
 399         rv = -ERESTARTSYS;
 400         if (r)
 401                 goto out_free_mem;
 402
 403         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 404                 rv = -ENODEV;
 405                 goto out_free_mem_lock;
 406         }
 407
 408         r = usb_autopm_get_interface(desc->intf);
 409         if (r < 0) {
 410                 rv = usb_translate_errors(r);
 411                 goto out_free_mem_lock;
 412         }
 413
 414         if (!(file->f_flags & O_NONBLOCK))
 415                 r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
 416                                                                 &desc->flags));
 417         else
 418                 if (test_bit(WDM_IN_USE, &desc->flags))
 419                         r = -EAGAIN;
 420
 421         if (test_bit(WDM_RESETTING, &desc->flags))
 422                 r = -EIO;
 423
 424         if (test_bit(WDM_DISCONNECTING, &desc->flags))
 425                 r = -ENODEV;
 426
 427         if (r < 0) {
 428                 rv = r;
 429                 goto out_free_mem_pm;
 430         }
 431
 432         req = desc->orq;
 433         usb_fill_control_urb(
 434                 desc->command,
 435                 interface_to_usbdev(desc->intf),
 436                 /* using common endpoint 0 */
 437                 usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
 438                 (unsigned char *)req,
 439                 buf,
 440                 count,
 441                 wdm_out_callback,
 442                 desc
 443         );
 444
 445         req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
 446                              USB_RECIP_INTERFACE);
 447         req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
 448         req->wValue = 0;
 449         req->wIndex = desc->inum; /* already converted */
 450         req->wLength = cpu_to_le16(count);
 451         set_bit(WDM_IN_USE, &desc->flags);
 452         desc->outbuf = buf;
 453
 454         rv = usb_submit_urb(desc->command, GFP_KERNEL);
 455         if (rv < 0) {
 456                 desc->outbuf = NULL;
 457                 clear_bit(WDM_IN_USE, &desc->flags);
 458                 wake_up_all(&desc->wait); /* for wdm_wait_for_response() */
 459                 dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
 460                 rv = usb_translate_errors(rv);
 461                 goto out_free_mem_pm;
 462         } else {
 463                 dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d\n",
 464                         le16_to_cpu(req->wIndex));
 465         }
 466
 467         usb_autopm_put_interface(desc->intf);
 468         mutex_unlock(&desc->wlock);
 469         return count;
 470
 471 out_free_mem_pm:
 472         usb_autopm_put_interface(desc->intf);
 473 out_free_mem_lock:
 474         mutex_unlock(&desc->wlock);
 475 out_free_mem:
 476         kfree(buf);
 477         return rv;
 478 }
 479
 480 /*
 481  * Submit the read urb if resp_count is non-zero.
 482  *
 483  * Called with desc->iuspin locked
 484  */
 485 static int service_outstanding_interrupt(struct wdm_device *desc)
 486 {
 487         int rv = 0;
 488
 489         /* submit read urb only if the device is waiting for it */
 490         if (!desc->resp_count || !--desc->resp_count)
 491                 goto out;
 492
 493         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 494                 rv = -ENODEV;
 495                 goto out;
 496         }
 497         if (test_bit(WDM_RESETTING, &desc->flags)) {
 498                 rv = -EIO;
 499                 goto out;
 500         }
 501
 502         set_bit(WDM_RESPONDING, &desc->flags);
 503         spin_unlock_irq(&desc->iuspin);
 504         rv = usb_submit_urb(desc->response, GFP_KERNEL);
 505         spin_lock_irq(&desc->iuspin);
 506         if (rv) {
 507                 if (!test_bit(WDM_DISCONNECTING, &desc->flags))
 508                         dev_err(&desc->intf->dev,
 509                                 "usb_submit_urb failed with result %d\n", rv);
 510
 511                 /* make sure the next notification trigger a submit */
 512                 clear_bit(WDM_RESPONDING, &desc->flags);
 513                 desc->resp_count = 0;
 514         }
 515 out:
 516         return rv;
 517 }
 518
 519 static ssize_t wdm_read
 520 (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 521 {
 522         int rv, cntr;
 523         int i = 0;
 524         struct wdm_device *desc = file->private_data;
 525
 526
 527         rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
 528         if (rv < 0)
 529                 return -ERESTARTSYS;
 530
 531         cntr = READ_ONCE(desc->length);
 532         if (cntr == 0) {
 533                 desc->read = 0;
 534 retry:
 535                 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 536                         rv = -ENODEV;
 537                         goto err;
 538                 }
 539                 if (test_bit(WDM_OVERFLOW, &desc->flags)) {
 540                         clear_bit(WDM_OVERFLOW, &desc->flags);
 541                         rv = -ENOBUFS;
 542                         goto err;
 543                 }
 544                 i++;
 545                 if (file->f_flags & O_NONBLOCK) {
 546                         if (!test_bit(WDM_READ, &desc->flags)) {
 547                                 rv = -EAGAIN;
 548                                 goto err;
 549                         }
 550                         rv = 0;
 551                 } else {
 552                         rv = wait_event_interruptible(desc->wait,
 553                                 test_bit(WDM_READ, &desc->flags));
 554                 }
 555
 556                 /* may have happened while we slept */
 557                 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 558                         rv = -ENODEV;
 559                         goto err;
 560                 }
 561                 if (test_bit(WDM_RESETTING, &desc->flags)) {
 562                         rv = -EIO;
 563                         goto err;
 564                 }
 565                 usb_mark_last_busy(interface_to_usbdev(desc->intf));
 566                 if (rv < 0) {
 567                         rv = -ERESTARTSYS;
 568                         goto err;
 569                 }
 570
 571                 spin_lock_irq(&desc->iuspin);
 572
 573                 if (desc->rerr) { /* read completed, error happened */
 574                         rv = usb_translate_errors(desc->rerr);
 575                         desc->rerr = 0;
 576                         spin_unlock_irq(&desc->iuspin);
 577                         goto err;
 578                 }
 579                 /*
 580                  * recheck whether we've lost the race
 581                  * against the completion handler
 582                  */
 583                 if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */
 584                         spin_unlock_irq(&desc->iuspin);
 585                         goto retry;
 586                 }
 587
 588                 if (!desc->reslength) { /* zero length read */
 589                         dev_dbg(&desc->intf->dev, "zero length - clearing WDM_READ\n");
 590                         clear_bit(WDM_READ, &desc->flags);
 591                         rv = service_outstanding_interrupt(desc);
 592                         spin_unlock_irq(&desc->iuspin);
 593                         if (rv < 0)
 594                                 goto err;
 595                         goto retry;
 596                 }
 597                 cntr = desc->length;
 598                 spin_unlock_irq(&desc->iuspin);
 599         }
 600
 601         if (cntr > count)
 602                 cntr = count;
 603         rv = copy_to_user(buffer, desc->ubuf, cntr);
 604         if (rv > 0) {
 605                 rv = -EFAULT;
 606                 goto err;
 607         }
 608
 609         spin_lock_irq(&desc->iuspin);
 610
 611         for (i = 0; i < desc->length - cntr; i++)
 612                 desc->ubuf[i] = desc->ubuf[i + cntr];
 613
 614         desc->length -= cntr;
 615         /* in case we had outstanding data */
 616         if (!desc->length) {
 617                 clear_bit(WDM_READ, &desc->flags);
 618                 service_outstanding_interrupt(desc);
 619         }
 620         spin_unlock_irq(&desc->iuspin);
 621         rv = cntr;
 622
 623 err:
 624         mutex_unlock(&desc->rlock);
 625         return rv;
 626 }
 627
 628 static int wdm_wait_for_response(struct file *file, long timeout)
 629 {
 630         struct wdm_device *desc = file->private_data;
 631         long rv; /* Use long here because (int) MAX_SCHEDULE_TIMEOUT < 0. */
 632
 633         /*
 634          * Needs both flags. We cannot do with one because resetting it would
 635          * cause a race with write() yet we need to signal a disconnect.
 636          */
 637         rv = wait_event_interruptible_timeout(desc->wait,
 638                               !test_bit(WDM_IN_USE, &desc->flags) ||
 639                               test_bit(WDM_DISCONNECTING, &desc->flags),
 640                               timeout);
 641
 642         /*
 643          * To report the correct error. This is best effort.
 644          * We are inevitably racing with the hardware.
 645          */
 646         if (test_bit(WDM_DISCONNECTING, &desc->flags))
 647                 return -ENODEV;
 648         if (!rv)
 649                 return -EIO;
 650         if (rv < 0)
 651                 return -EINTR;
 652
 653         spin_lock_irq(&desc->iuspin);
 654         rv = desc->werr;
 655         desc->werr = 0;
 656         spin_unlock_irq(&desc->iuspin);
 657
 658         return usb_translate_errors(rv);
 659
 660 }
 661
 662 /*
 663  * You need to send a signal when you react to malicious or defective hardware.
 664  * Also, don't abort when fsync() returned -EINVAL, for older kernels which do
 665  * not implement wdm_flush() will return -EINVAL.
 666  */
 667 static int wdm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 668 {
 669         return wdm_wait_for_response(file, MAX_SCHEDULE_TIMEOUT);
 670 }
 671
 672 /*
 673  * Same with wdm_fsync(), except it uses finite timeout in order to react to
 674  * malicious or defective hardware which ceased communication after close() was
 675  * implicitly called due to process termination.
 676  */
 677 static int wdm_flush(struct file *file, fl_owner_t id)
 678 {
 679         return wdm_wait_for_response(file, WDM_FLUSH_TIMEOUT);
 680 }
 681
 682 static __poll_t wdm_poll(struct file *file, struct poll_table_struct *wait)
 683 {
 684         struct wdm_device *desc = file->private_data;
 685         unsigned long flags;
 686         __poll_t mask = 0;
 687
 688         spin_lock_irqsave(&desc->iuspin, flags);
 689         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 690                 mask = EPOLLHUP | EPOLLERR;
 691                 spin_unlock_irqrestore(&desc->iuspin, flags);
 692                 goto desc_out;
 693         }
 694         if (test_bit(WDM_READ, &desc->flags))
 695                 mask = EPOLLIN | EPOLLRDNORM;
 696         if (desc->rerr || desc->werr)
 697                 mask |= EPOLLERR;
 698         if (!test_bit(WDM_IN_USE, &desc->flags))
 699                 mask |= EPOLLOUT | EPOLLWRNORM;
 700         spin_unlock_irqrestore(&desc->iuspin, flags);
 701
 702         poll_wait(file, &desc->wait, wait);
 703
 704 desc_out:
 705         return mask;
 706 }
 707
 708 static int wdm_open(struct inode *inode, struct file *file)
 709 {
 710         int minor = iminor(inode);
 711         int rv = -ENODEV;
 712         struct usb_interface *intf;
 713         struct wdm_device *desc;
 714
 715         mutex_lock(&wdm_mutex);
 716         desc = wdm_find_device_by_minor(minor);
 717         if (!desc)
 718                 goto out;
 719
 720         intf = desc->intf;
 721         if (test_bit(WDM_DISCONNECTING, &desc->flags))
 722                 goto out;
 723         file->private_data = desc;
 724
 725         if (test_bit(WDM_WWAN_IN_USE, &desc->flags)) {
 726                 rv = -EBUSY;
 727                 goto out;
 728         }
 729
 730         rv = usb_autopm_get_interface(desc->intf);
 731         if (rv < 0) {
 732                 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
 733                 goto out;
 734         }
 735
 736         /* using write lock to protect desc->count */
 737         mutex_lock(&desc->wlock);
 738         if (!desc->count++) {
 739                 desc->werr = 0;
 740                 desc->rerr = 0;
 741                 rv = usb_submit_urb(desc->validity, GFP_KERNEL);
 742                 if (rv < 0) {
 743                         desc->count--;
 744                         dev_err(&desc->intf->dev,
 745                                 "Error submitting int urb - %d\n", rv);
 746                         rv = usb_translate_errors(rv);
 747                 }
 748         } else {
 749                 rv = 0;
 750         }
 751         mutex_unlock(&desc->wlock);
 752         if (desc->count == 1)
 753                 desc->manage_power(intf, 1);
 754         usb_autopm_put_interface(desc->intf);
 755 out:
 756         mutex_unlock(&wdm_mutex);
 757         return rv;
 758 }
 759
 760 static int wdm_release(struct inode *inode, struct file *file)
 761 {
 762         struct wdm_device *desc = file->private_data;
 763
 764         mutex_lock(&wdm_mutex);
 765
 766         /* using write lock to protect desc->count */
 767         mutex_lock(&desc->wlock);
 768         desc->count--;
 769         mutex_unlock(&desc->wlock);
 770
 771         if (!desc->count) {
 772                 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
 773                         dev_dbg(&desc->intf->dev, "wdm_release: cleanup\n");
 774                         poison_urbs(desc);
 775                         spin_lock_irq(&desc->iuspin);
 776                         desc->resp_count = 0;
 777                         spin_unlock_irq(&desc->iuspin);
 778                         desc->manage_power(desc->intf, 0);
 779                         unpoison_urbs(desc);
 780                 } else {
 781                         /* must avoid dev_printk here as desc->intf is invalid */
 782                         pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
 783                         cleanup(desc);
 784                 }
 785         }
 786         mutex_unlock(&wdm_mutex);
 787         return 0;
 788 }
 789
 790 static long wdm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 791 {
 792         struct wdm_device *desc = file->private_data;
 793         int rv = 0;
 794
 795         switch (cmd) {
 796         case IOCTL_WDM_MAX_COMMAND:
 797                 if (copy_to_user((void __user *)arg, &desc->wMaxCommand, sizeof(desc->wMaxCommand)))
 798                         rv = -EFAULT;
 799                 break;
 800         default:
 801                 rv = -ENOTTY;
 802         }
 803         return rv;
 804 }
 805
 806 static const struct file_operations wdm_fops = {
 807         .owner =        THIS_MODULE,
 808         .read =         wdm_read,
 809         .write =        wdm_write,
 810         .fsync =        wdm_fsync,
 811         .open =         wdm_open,
 812         .flush =        wdm_flush,
 813         .release =      wdm_release,
 814         .poll =         wdm_poll,
 815         .unlocked_ioctl = wdm_ioctl,
 816         .compat_ioctl = compat_ptr_ioctl,
 817         .llseek =       noop_llseek,
 818 };
 819
 820 static struct usb_class_driver wdm_class = {
 821         .name =         "cdc-wdm%d",
 822         .fops =         &wdm_fops,
 823         .minor_base =   WDM_MINOR_BASE,
 824 };
 825
 826 /* --- WWAN framework integration --- */
 827 #ifdef CONFIG_WWAN_CORE
 828 static int wdm_wwan_port_start(struct wwan_port *port)
 829 {
 830         struct wdm_device *desc = wwan_port_get_drvdata(port);
 831
 832         /* The interface is both exposed via the WWAN framework and as a
 833          * legacy usbmisc chardev. If chardev is already open, just fail
 834          * to prevent concurrent usage. Otherwise, switch to WWAN mode.
 835          */
 836         mutex_lock(&wdm_mutex);
 837         if (desc->count) {
 838                 mutex_unlock(&wdm_mutex);
 839                 return -EBUSY;
 840         }
 841         set_bit(WDM_WWAN_IN_USE, &desc->flags);
 842         mutex_unlock(&wdm_mutex);
 843
 844         desc->manage_power(desc->intf, 1);
 845
 846         /* tx is allowed */
 847         wwan_port_txon(port);
 848
 849         /* Start getting events */
 850         return usb_submit_urb(desc->validity, GFP_KERNEL);
 851 }
 852
 853 static void wdm_wwan_port_stop(struct wwan_port *port)
 854 {
 855         struct wdm_device *desc = wwan_port_get_drvdata(port);
 856
 857         /* Stop all transfers and disable WWAN mode */
 858         poison_urbs(desc);
 859         desc->manage_power(desc->intf, 0);
 860         clear_bit(WDM_READ, &desc->flags);
 861         clear_bit(WDM_WWAN_IN_USE, &desc->flags);
 862         unpoison_urbs(desc);
 863 }
 864
 865 static void wdm_wwan_port_tx_complete(struct urb *urb)
 866 {
 867         struct sk_buff *skb = urb->context;
 868         struct wdm_device *desc = skb_shinfo(skb)->destructor_arg;
 869
 870         usb_autopm_put_interface(desc->intf);
 871         wwan_port_txon(desc->wwanp);
 872         kfree_skb(skb);
 873 }
 874
 875 static int wdm_wwan_port_tx(struct wwan_port *port, struct sk_buff *skb)
 876 {
 877         struct wdm_device *desc = wwan_port_get_drvdata(port);
 878         struct usb_interface *intf = desc->intf;
 879         struct usb_ctrlrequest *req = desc->orq;
 880         int rv;
 881
 882         rv = usb_autopm_get_interface(intf);
 883         if (rv)
 884                 return rv;
 885
 886         usb_fill_control_urb(
 887                 desc->command,
 888                 interface_to_usbdev(intf),
 889                 usb_sndctrlpipe(interface_to_usbdev(intf), 0),
 890                 (unsigned char *)req,
 891                 skb->data,
 892                 skb->len,
 893                 wdm_wwan_port_tx_complete,
 894                 skb
 895         );
 896
 897         req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
 898         req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
 899         req->wValue = 0;
 900         req->wIndex = desc->inum;
 901         req->wLength = cpu_to_le16(skb->len);
 902
 903         skb_shinfo(skb)->destructor_arg = desc;
 904
 905         rv = usb_submit_urb(desc->command, GFP_KERNEL);
 906         if (rv)
 907                 usb_autopm_put_interface(intf);
 908         else /* One transfer at a time, stop TX until URB completion */
 909                 wwan_port_txoff(port);
 910
 911         return rv;
 912 }
 913
 914 static struct wwan_port_ops wdm_wwan_port_ops = {
 915         .start = wdm_wwan_port_start,
 916         .stop = wdm_wwan_port_stop,
 917         .tx = wdm_wwan_port_tx,
 918 };
 919
 920 static void wdm_wwan_init(struct wdm_device *desc)
 921 {
 922         struct usb_interface *intf = desc->intf;
 923         struct wwan_port *port;
 924
 925         /* Only register to WWAN core if protocol/type is known */
 926         if (desc->wwanp_type == WWAN_PORT_UNKNOWN) {
 927                 dev_info(&intf->dev, "Unknown control protocol\n");
 928                 return;
 929         }
 930
 931         port = wwan_create_port(&intf->dev, desc->wwanp_type, &wdm_wwan_port_ops, desc);
 932         if (IS_ERR(port)) {
 933                 dev_err(&intf->dev, "%s: Unable to create WWAN port\n",
 934                         dev_name(intf->usb_dev));
 935                 return;
 936         }
 937
 938         desc->wwanp = port;
 939 }
 940
 941 static void wdm_wwan_deinit(struct wdm_device *desc)
 942 {
 943         if (!desc->wwanp)
 944                 return;
 945
 946         wwan_remove_port(desc->wwanp);
 947         desc->wwanp = NULL;
 948 }
 949
 950 static void wdm_wwan_rx(struct wdm_device *desc, int length)
 951 {
 952         struct wwan_port *port = desc->wwanp;
 953         struct sk_buff *skb;
 954
 955         /* Forward data to WWAN port */
 956         skb = alloc_skb(length, GFP_ATOMIC);
 957         if (!skb)
 958                 return;
 959
 960         memcpy(skb_put(skb, length), desc->inbuf, length);
 961         wwan_port_rx(port, skb);
 962
 963         /* inbuf has been copied, it is safe to check for outstanding data */
 964         schedule_work(&desc->service_outs_intr);
 965 }
 966 #else /* CONFIG_WWAN_CORE */
 967 static void wdm_wwan_init(struct wdm_device *desc) {}
 968 static void wdm_wwan_deinit(struct wdm_device *desc) {}
 969 static void wdm_wwan_rx(struct wdm_device *desc, int length) {}
 970 #endif /* CONFIG_WWAN_CORE */
 971
 972 /* --- error handling --- */
 973 static void wdm_rxwork(struct work_struct *work)
 974 {
 975         struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
 976         unsigned long flags;
 977         int rv = 0;
 978         int responding;
 979
 980         spin_lock_irqsave(&desc->iuspin, flags);
 981         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 982                 spin_unlock_irqrestore(&desc->iuspin, flags);
 983         } else {
 984                 responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
 985                 spin_unlock_irqrestore(&desc->iuspin, flags);
 986                 if (!responding)
 987                         rv = usb_submit_urb(desc->response, GFP_KERNEL);
 988                 if (rv < 0 && rv != -EPERM) {
 989                         spin_lock_irqsave(&desc->iuspin, flags);
 990                         clear_bit(WDM_RESPONDING, &desc->flags);
 991                         if (!test_bit(WDM_DISCONNECTING, &desc->flags))
 992                                 schedule_work(&desc->rxwork);
 993                         spin_unlock_irqrestore(&desc->iuspin, flags);
 994                 }
 995         }
 996 }
 997
 998 static void service_interrupt_work(struct work_struct *work)
 999 {
1000         struct wdm_device *desc;
1001
1002         desc = container_of(work, struct wdm_device, service_outs_intr);
1003
1004         spin_lock_irq(&desc->iuspin);
1005         service_outstanding_interrupt(desc);
1006         if (!desc->resp_count) {
1007                 set_bit(WDM_READ, &desc->flags);
1008                 wake_up(&desc->wait);
1009         }
1010         spin_unlock_irq(&desc->iuspin);
1011 }
1012
1013 /* --- hotplug --- */
1014
1015 static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
1016                       u16 bufsize, enum wwan_port_type type,
1017                       int (*manage_power)(struct usb_interface *, int))
1018 {
1019         int rv = -ENOMEM;
1020         struct wdm_device *desc;
1021
1022         desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
1023         if (!desc)
1024                 goto out;
1025         INIT_LIST_HEAD(&desc->device_list);
1026         mutex_init(&desc->rlock);
1027         mutex_init(&desc->wlock);
1028         spin_lock_init(&desc->iuspin);
1029         init_waitqueue_head(&desc->wait);
1030         desc->wMaxCommand = bufsize;
1031         /* this will be expanded and needed in hardware endianness */
1032         desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
1033         desc->intf = intf;
1034         desc->wwanp_type = type;
1035         INIT_WORK(&desc->rxwork, wdm_rxwork);
1036         INIT_WORK(&desc->service_outs_intr, service_interrupt_work);
1037
1038         if (!usb_endpoint_is_int_in(ep)) {
1039                 rv = -EINVAL;
1040                 goto err;
1041         }
1042
1043         desc->wMaxPacketSize = usb_endpoint_maxp(ep);
1044
1045         desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
1046         if (!desc->orq)
1047                 goto err;
1048         desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
1049         if (!desc->irq)
1050                 goto err;
1051
1052         desc->validity = usb_alloc_urb(0, GFP_KERNEL);
1053         if (!desc->validity)
1054                 goto err;
1055
1056         desc->response = usb_alloc_urb(0, GFP_KERNEL);
1057         if (!desc->response)
1058                 goto err;
1059
1060         desc->command = usb_alloc_urb(0, GFP_KERNEL);
1061         if (!desc->command)
1062                 goto err;
1063
1064         desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
1065         if (!desc->ubuf)
1066                 goto err;
1067
1068         desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);
1069         if (!desc->sbuf)
1070                 goto err;
1071
1072         desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
1073         if (!desc->inbuf)
1074                 goto err;
1075
1076         usb_fill_int_urb(
1077                 desc->validity,
1078                 interface_to_usbdev(intf),
1079                 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
1080                 desc->sbuf,
1081                 desc->wMaxPacketSize,
1082                 wdm_int_callback,
1083                 desc,
1084                 ep->bInterval
1085         );
1086
1087         desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
1088         desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
1089         desc->irq->wValue = 0;
1090         desc->irq->wIndex = desc->inum; /* already converted */
1091         desc->irq->wLength = cpu_to_le16(desc->wMaxCommand);
1092
1093         usb_fill_control_urb(
1094                 desc->response,
1095                 interface_to_usbdev(intf),
1096                 /* using common endpoint 0 */
1097                 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
1098                 (unsigned char *)desc->irq,
1099                 desc->inbuf,
1100                 desc->wMaxCommand,
1101                 wdm_in_callback,
1102                 desc
1103         );
1104
1105         desc->manage_power = manage_power;
1106
1107         spin_lock(&wdm_device_list_lock);
1108         list_add(&desc->device_list, &wdm_device_list);
1109         spin_unlock(&wdm_device_list_lock);
1110
1111         rv = usb_register_dev(intf, &wdm_class);
1112         if (rv < 0)
1113                 goto err;
1114         else
1115                 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev));
1116
1117         wdm_wwan_init(desc);
1118
1119 out:
1120         return rv;
1121 err:
1122         spin_lock(&wdm_device_list_lock);
1123         list_del(&desc->device_list);
1124         spin_unlock(&wdm_device_list_lock);
1125         cleanup(desc);
1126         return rv;
1127 }
1128
1129 static int wdm_manage_power(struct usb_interface *intf, int on)
1130 {
1131         /* need autopm_get/put here to ensure the usbcore sees the new value */
1132         int rv = usb_autopm_get_interface(intf);
1133
1134         intf->needs_remote_wakeup = on;
1135         if (!rv)
1136                 usb_autopm_put_interface(intf);
1137         return 0;
1138 }
1139
1140 static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
1141 {
1142         int rv = -EINVAL;
1143         struct usb_host_interface *iface;
1144         struct usb_endpoint_descriptor *ep;
1145         struct usb_cdc_parsed_header hdr;
1146         u8 *buffer = intf->altsetting->extra;
1147         int buflen = intf->altsetting->extralen;
1148         u16 maxcom = WDM_DEFAULT_BUFSIZE;
1149
1150         if (!buffer)
1151                 goto err;
1152
1153         cdc_parse_cdc_header(&hdr, intf, buffer, buflen);
1154
1155         if (hdr.usb_cdc_dmm_desc)
1156                 maxcom = le16_to_cpu(hdr.usb_cdc_dmm_desc->wMaxCommand);
1157
1158         iface = intf->cur_altsetting;
1159         if (iface->desc.bNumEndpoints != 1)
1160                 goto err;
1161         ep = &iface->endpoint[0].desc;
1162
1163         rv = wdm_create(intf, ep, maxcom, WWAN_PORT_UNKNOWN, &wdm_manage_power);
1164
1165 err:
1166         return rv;
1167 }
1168
1169 /**
1170  * usb_cdc_wdm_register - register a WDM subdriver
1171  * @intf: usb interface the subdriver will associate with
1172  * @ep: interrupt endpoint to monitor for notifications
1173  * @bufsize: maximum message size to support for read/write
1174  * @type: Type/protocol of the transported data (MBIM, QMI...)
1175  * @manage_power: call-back invoked during open and release to
1176  *                manage the device's power
1177  * Create WDM usb class character device and associate it with intf
1178  * without binding, allowing another driver to manage the interface.
1179  *
1180  * The subdriver will manage the given interrupt endpoint exclusively
1181  * and will issue control requests referring to the given intf. It
1182  * will otherwise avoid interferring, and in particular not do
1183  * usb_set_intfdata/usb_get_intfdata on intf.
1184  *
1185  * The return value is a pointer to the subdriver's struct usb_driver.
1186  * The registering driver is responsible for calling this subdriver's
1187  * disconnect, suspend, resume, pre_reset and post_reset methods from
1188  * its own.
1189  */
1190 struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,
1191                                         struct usb_endpoint_descriptor *ep,
1192                                         int bufsize, enum wwan_port_type type,
1193                                         int (*manage_power)(struct usb_interface *, int))
1194 {
1195         int rv;
1196
1197         rv = wdm_create(intf, ep, bufsize, type, manage_power);
1198         if (rv < 0)
1199                 goto err;
1200
1201         return &wdm_driver;
1202 err:
1203         return ERR_PTR(rv);
1204 }
1205 EXPORT_SYMBOL(usb_cdc_wdm_register);
1206
1207 static void wdm_disconnect(struct usb_interface *intf)
1208 {
1209         struct wdm_device *desc;
1210         unsigned long flags;
1211
1212         usb_deregister_dev(intf, &wdm_class);
1213         desc = wdm_find_device(intf);
1214         mutex_lock(&wdm_mutex);
1215
1216         wdm_wwan_deinit(desc);
1217
1218         /* the spinlock makes sure no new urbs are generated in the callbacks */
1219         spin_lock_irqsave(&desc->iuspin, flags);
1220         set_bit(WDM_DISCONNECTING, &desc->flags);
1221         set_bit(WDM_READ, &desc->flags);
1222         spin_unlock_irqrestore(&desc->iuspin, flags);
1223         wake_up_all(&desc->wait);
1224         mutex_lock(&desc->rlock);
1225         mutex_lock(&desc->wlock);
1226         poison_urbs(desc);
1227         cancel_work_sync(&desc->rxwork);
1228         cancel_work_sync(&desc->service_outs_intr);
1229         mutex_unlock(&desc->wlock);
1230         mutex_unlock(&desc->rlock);
1231
1232         /* the desc->intf pointer used as list key is now invalid */
1233         spin_lock(&wdm_device_list_lock);
1234         list_del(&desc->device_list);
1235         spin_unlock(&wdm_device_list_lock);
1236
1237         if (!desc->count)
1238                 cleanup(desc);
1239         else
1240                 dev_dbg(&intf->dev, "%d open files - postponing cleanup\n", desc->count);
1241         mutex_unlock(&wdm_mutex);
1242 }
1243
1244 #ifdef CONFIG_PM
1245 static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
1246 {
1247         struct wdm_device *desc = wdm_find_device(intf);
1248         int rv = 0;
1249
1250         dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
1251
1252         /* if this is an autosuspend the caller does the locking */
1253         if (!PMSG_IS_AUTO(message)) {
1254                 mutex_lock(&desc->rlock);
1255                 mutex_lock(&desc->wlock);
1256         }
1257         spin_lock_irq(&desc->iuspin);
1258
1259         if (PMSG_IS_AUTO(message) &&
1260                         (test_bit(WDM_IN_USE, &desc->flags)
1261                         || test_bit(WDM_RESPONDING, &desc->flags))) {
1262                 spin_unlock_irq(&desc->iuspin);
1263                 rv = -EBUSY;
1264         } else {
1265
1266                 set_bit(WDM_SUSPENDING, &desc->flags);
1267                 spin_unlock_irq(&desc->iuspin);
1268                 /* callback submits work - order is essential */
1269                 poison_urbs(desc);
1270                 cancel_work_sync(&desc->rxwork);
1271                 cancel_work_sync(&desc->service_outs_intr);
1272                 unpoison_urbs(desc);
1273         }
1274         if (!PMSG_IS_AUTO(message)) {
1275                 mutex_unlock(&desc->wlock);
1276                 mutex_unlock(&desc->rlock);
1277         }
1278
1279         return rv;
1280 }
1281 #endif
1282
1283 static int recover_from_urb_loss(struct wdm_device *desc)
1284 {
1285         int rv = 0;
1286
1287         if (desc->count) {
1288                 rv = usb_submit_urb(desc->validity, GFP_NOIO);
1289                 if (rv < 0)
1290                         dev_err(&desc->intf->dev,
1291                                 "Error resume submitting int urb - %d\n", rv);
1292         }
1293         return rv;
1294 }
1295
1296 #ifdef CONFIG_PM
1297 static int wdm_resume(struct usb_interface *intf)
1298 {
1299         struct wdm_device *desc = wdm_find_device(intf);
1300         int rv;
1301
1302         dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
1303
1304         clear_bit(WDM_SUSPENDING, &desc->flags);
1305         rv = recover_from_urb_loss(desc);
1306
1307         return rv;
1308 }
1309 #endif
1310
1311 static int wdm_pre_reset(struct usb_interface *intf)
1312 {
1313         struct wdm_device *desc = wdm_find_device(intf);
1314
1315         /*
1316          * we notify everybody using poll of
1317          * an exceptional situation
1318          * must be done before recovery lest a spontaneous
1319          * message from the device is lost
1320          */
1321         spin_lock_irq(&desc->iuspin);
1322         set_bit(WDM_RESETTING, &desc->flags);   /* inform read/write */
1323         set_bit(WDM_READ, &desc->flags);        /* unblock read */
1324         clear_bit(WDM_IN_USE, &desc->flags);    /* unblock write */
1325         desc->rerr = -EINTR;
1326         spin_unlock_irq(&desc->iuspin);
1327         wake_up_all(&desc->wait);
1328         mutex_lock(&desc->rlock);
1329         mutex_lock(&desc->wlock);
1330         poison_urbs(desc);
1331         cancel_work_sync(&desc->rxwork);
1332         cancel_work_sync(&desc->service_outs_intr);
1333         return 0;
1334 }
1335
1336 static int wdm_post_reset(struct usb_interface *intf)
1337 {
1338         struct wdm_device *desc = wdm_find_device(intf);
1339         int rv;
1340
1341         unpoison_urbs(desc);
1342         clear_bit(WDM_OVERFLOW, &desc->flags);
1343         clear_bit(WDM_RESETTING, &desc->flags);
1344         rv = recover_from_urb_loss(desc);
1345         mutex_unlock(&desc->wlock);
1346         mutex_unlock(&desc->rlock);
1347         return rv;
1348 }
1349
1350 static struct usb_driver wdm_driver = {
1351         .name =         "cdc_wdm",
1352         .probe =        wdm_probe,
1353         .disconnect =   wdm_disconnect,
1354 #ifdef CONFIG_PM
1355         .suspend =      wdm_suspend,
1356         .resume =       wdm_resume,
1357         .reset_resume = wdm_resume,
1358 #endif
1359         .pre_reset =    wdm_pre_reset,
1360         .post_reset =   wdm_post_reset,
1361         .id_table =     wdm_ids,
1362         .supports_autosuspend = 1,
1363         .disable_hub_initiated_lpm = 1,
1364 };
1365
1366 module_usb_driver(wdm_driver);
1367
1368 MODULE_AUTHOR(DRIVER_AUTHOR);
1369 MODULE_DESCRIPTION(DRIVER_DESC);
1370 MODULE_LICENSE("GPL");