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                         clear_bit(WDM_RESPONDING, &desc->flags);
 778                         spin_unlock_irq(&desc->iuspin);
 779                         desc->manage_power(desc->intf, 0);
 780                         unpoison_urbs(desc);
 781                 } else {
 782                         /* must avoid dev_printk here as desc->intf is invalid */
 783                         pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
 784                         cleanup(desc);
 785                 }
 786         }
 787         mutex_unlock(&wdm_mutex);
 788         return 0;
 789 }
 790
 791 static long wdm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 792 {
 793         struct wdm_device *desc = file->private_data;
 794         int rv = 0;
 795
 796         switch (cmd) {
 797         case IOCTL_WDM_MAX_COMMAND:
 798                 if (copy_to_user((void __user *)arg, &desc->wMaxCommand, sizeof(desc->wMaxCommand)))
 799                         rv = -EFAULT;
 800                 break;
 801         default:
 802                 rv = -ENOTTY;
 803         }
 804         return rv;
 805 }
 806
 807 static const struct file_operations wdm_fops = {
 808         .owner =        THIS_MODULE,
 809         .read =         wdm_read,
 810         .write =        wdm_write,
 811         .fsync =        wdm_fsync,
 812         .open =         wdm_open,
 813         .flush =        wdm_flush,
 814         .release =      wdm_release,
 815         .poll =         wdm_poll,
 816         .unlocked_ioctl = wdm_ioctl,
 817         .compat_ioctl = compat_ptr_ioctl,
 818         .llseek =       noop_llseek,
 819 };
 820
 821 static struct usb_class_driver wdm_class = {
 822         .name =         "cdc-wdm%d",
 823         .fops =         &wdm_fops,
 824         .minor_base =   WDM_MINOR_BASE,
 825 };
 826
 827 /* --- WWAN framework integration --- */
 828 #ifdef CONFIG_WWAN
 829 static int wdm_wwan_port_start(struct wwan_port *port)
 830 {
 831         struct wdm_device *desc = wwan_port_get_drvdata(port);
 832
 833         /* The interface is both exposed via the WWAN framework and as a
 834          * legacy usbmisc chardev. If chardev is already open, just fail
 835          * to prevent concurrent usage. Otherwise, switch to WWAN mode.
 836          */
 837         mutex_lock(&wdm_mutex);
 838         if (desc->count) {
 839                 mutex_unlock(&wdm_mutex);
 840                 return -EBUSY;
 841         }
 842         set_bit(WDM_WWAN_IN_USE, &desc->flags);
 843         mutex_unlock(&wdm_mutex);
 844
 845         desc->manage_power(desc->intf, 1);
 846
 847         /* tx is allowed */
 848         wwan_port_txon(port);
 849
 850         /* Start getting events */
 851         return usb_submit_urb(desc->validity, GFP_KERNEL);
 852 }
 853
 854 static void wdm_wwan_port_stop(struct wwan_port *port)
 855 {
 856         struct wdm_device *desc = wwan_port_get_drvdata(port);
 857
 858         /* Stop all transfers and disable WWAN mode */
 859         poison_urbs(desc);
 860         desc->manage_power(desc->intf, 0);
 861         clear_bit(WDM_READ, &desc->flags);
 862         clear_bit(WDM_WWAN_IN_USE, &desc->flags);
 863         unpoison_urbs(desc);
 864 }
 865
 866 static void wdm_wwan_port_tx_complete(struct urb *urb)
 867 {
 868         struct sk_buff *skb = urb->context;
 869         struct wdm_device *desc = skb_shinfo(skb)->destructor_arg;
 870
 871         usb_autopm_put_interface(desc->intf);
 872         wwan_port_txon(desc->wwanp);
 873         kfree_skb(skb);
 874 }
 875
 876 static int wdm_wwan_port_tx(struct wwan_port *port, struct sk_buff *skb)
 877 {
 878         struct wdm_device *desc = wwan_port_get_drvdata(port);
 879         struct usb_interface *intf = desc->intf;
 880         struct usb_ctrlrequest *req = desc->orq;
 881         int rv;
 882
 883         rv = usb_autopm_get_interface(intf);
 884         if (rv)
 885                 return rv;
 886
 887         usb_fill_control_urb(
 888                 desc->command,
 889                 interface_to_usbdev(intf),
 890                 usb_sndctrlpipe(interface_to_usbdev(intf), 0),
 891                 (unsigned char *)req,
 892                 skb->data,
 893                 skb->len,
 894                 wdm_wwan_port_tx_complete,
 895                 skb
 896         );
 897
 898         req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
 899         req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
 900         req->wValue = 0;
 901         req->wIndex = desc->inum;
 902         req->wLength = cpu_to_le16(skb->len);
 903
 904         skb_shinfo(skb)->destructor_arg = desc;
 905
 906         rv = usb_submit_urb(desc->command, GFP_KERNEL);
 907         if (rv)
 908                 usb_autopm_put_interface(intf);
 909         else /* One transfer at a time, stop TX until URB completion */
 910                 wwan_port_txoff(port);
 911
 912         return rv;
 913 }
 914
 915 static const struct wwan_port_ops wdm_wwan_port_ops = {
 916         .start = wdm_wwan_port_start,
 917         .stop = wdm_wwan_port_stop,
 918         .tx = wdm_wwan_port_tx,
 919 };
 920
 921 static void wdm_wwan_init(struct wdm_device *desc)
 922 {
 923         struct usb_interface *intf = desc->intf;
 924         struct wwan_port *port;
 925
 926         /* Only register to WWAN core if protocol/type is known */
 927         if (desc->wwanp_type == WWAN_PORT_UNKNOWN) {
 928                 dev_info(&intf->dev, "Unknown control protocol\n");
 929                 return;
 930         }
 931
 932         port = wwan_create_port(&intf->dev, desc->wwanp_type, &wdm_wwan_port_ops,
 933                                 NULL, desc);
 934         if (IS_ERR(port)) {
 935                 dev_err(&intf->dev, "%s: Unable to create WWAN port\n",
 936                         dev_name(intf->usb_dev));
 937                 return;
 938         }
 939
 940         desc->wwanp = port;
 941 }
 942
 943 static void wdm_wwan_deinit(struct wdm_device *desc)
 944 {
 945         if (!desc->wwanp)
 946                 return;
 947
 948         wwan_remove_port(desc->wwanp);
 949         desc->wwanp = NULL;
 950 }
 951
 952 static void wdm_wwan_rx(struct wdm_device *desc, int length)
 953 {
 954         struct wwan_port *port = desc->wwanp;
 955         struct sk_buff *skb;
 956
 957         /* Forward data to WWAN port */
 958         skb = alloc_skb(length, GFP_ATOMIC);
 959         if (!skb)
 960                 return;
 961
 962         skb_put_data(skb, desc->inbuf, length);
 963         wwan_port_rx(port, skb);
 964
 965         /* inbuf has been copied, it is safe to check for outstanding data */
 966         schedule_work(&desc->service_outs_intr);
 967 }
 968 #else /* CONFIG_WWAN */
 969 static void wdm_wwan_init(struct wdm_device *desc) {}
 970 static void wdm_wwan_deinit(struct wdm_device *desc) {}
 971 static void wdm_wwan_rx(struct wdm_device *desc, int length) {}
 972 #endif /* CONFIG_WWAN */
 973
 974 /* --- error handling --- */
 975 static void wdm_rxwork(struct work_struct *work)
 976 {
 977         struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
 978         unsigned long flags;
 979         int rv = 0;
 980         int responding;
 981
 982         spin_lock_irqsave(&desc->iuspin, flags);
 983         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 984                 spin_unlock_irqrestore(&desc->iuspin, flags);
 985         } else {
 986                 responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
 987                 spin_unlock_irqrestore(&desc->iuspin, flags);
 988                 if (!responding)
 989                         rv = usb_submit_urb(desc->response, GFP_KERNEL);
 990                 if (rv < 0 && rv != -EPERM) {
 991                         spin_lock_irqsave(&desc->iuspin, flags);
 992                         clear_bit(WDM_RESPONDING, &desc->flags);
 993                         if (!test_bit(WDM_DISCONNECTING, &desc->flags))
 994                                 schedule_work(&desc->rxwork);
 995                         spin_unlock_irqrestore(&desc->iuspin, flags);
 996                 }
 997         }
 998 }
 999
1000 static void service_interrupt_work(struct work_struct *work)
1001 {
1002         struct wdm_device *desc;
1003
1004         desc = container_of(work, struct wdm_device, service_outs_intr);
1005
1006         spin_lock_irq(&desc->iuspin);
1007         service_outstanding_interrupt(desc);
1008         if (!desc->resp_count) {
1009                 set_bit(WDM_READ, &desc->flags);
1010                 wake_up(&desc->wait);
1011         }
1012         spin_unlock_irq(&desc->iuspin);
1013 }
1014
1015 /* --- hotplug --- */
1016
1017 static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
1018                       u16 bufsize, enum wwan_port_type type,
1019                       int (*manage_power)(struct usb_interface *, int))
1020 {
1021         int rv = -ENOMEM;
1022         struct wdm_device *desc;
1023
1024         desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
1025         if (!desc)
1026                 goto out;
1027         INIT_LIST_HEAD(&desc->device_list);
1028         mutex_init(&desc->rlock);
1029         mutex_init(&desc->wlock);
1030         spin_lock_init(&desc->iuspin);
1031         init_waitqueue_head(&desc->wait);
1032         desc->wMaxCommand = bufsize;
1033         /* this will be expanded and needed in hardware endianness */
1034         desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
1035         desc->intf = intf;
1036         desc->wwanp_type = type;
1037         INIT_WORK(&desc->rxwork, wdm_rxwork);
1038         INIT_WORK(&desc->service_outs_intr, service_interrupt_work);
1039
1040         if (!usb_endpoint_is_int_in(ep)) {
1041                 rv = -EINVAL;
1042                 goto err;
1043         }
1044
1045         desc->wMaxPacketSize = usb_endpoint_maxp(ep);
1046
1047         desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
1048         if (!desc->orq)
1049                 goto err;
1050         desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
1051         if (!desc->irq)
1052                 goto err;
1053
1054         desc->validity = usb_alloc_urb(0, GFP_KERNEL);
1055         if (!desc->validity)
1056                 goto err;
1057
1058         desc->response = usb_alloc_urb(0, GFP_KERNEL);
1059         if (!desc->response)
1060                 goto err;
1061
1062         desc->command = usb_alloc_urb(0, GFP_KERNEL);
1063         if (!desc->command)
1064                 goto err;
1065
1066         desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
1067         if (!desc->ubuf)
1068                 goto err;
1069
1070         desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);
1071         if (!desc->sbuf)
1072                 goto err;
1073
1074         desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
1075         if (!desc->inbuf)
1076                 goto err;
1077
1078         usb_fill_int_urb(
1079                 desc->validity,
1080                 interface_to_usbdev(intf),
1081                 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
1082                 desc->sbuf,
1083                 desc->wMaxPacketSize,
1084                 wdm_int_callback,
1085                 desc,
1086                 ep->bInterval
1087         );
1088
1089         desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
1090         desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
1091         desc->irq->wValue = 0;
1092         desc->irq->wIndex = desc->inum; /* already converted */
1093         desc->irq->wLength = cpu_to_le16(desc->wMaxCommand);
1094
1095         usb_fill_control_urb(
1096                 desc->response,
1097                 interface_to_usbdev(intf),
1098                 /* using common endpoint 0 */
1099                 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
1100                 (unsigned char *)desc->irq,
1101                 desc->inbuf,
1102                 desc->wMaxCommand,
1103                 wdm_in_callback,
1104                 desc
1105         );
1106
1107         desc->manage_power = manage_power;
1108
1109         spin_lock(&wdm_device_list_lock);
1110         list_add(&desc->device_list, &wdm_device_list);
1111         spin_unlock(&wdm_device_list_lock);
1112
1113         rv = usb_register_dev(intf, &wdm_class);
1114         if (rv < 0)
1115                 goto err;
1116         else
1117                 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev));
1118
1119         wdm_wwan_init(desc);
1120
1121 out:
1122         return rv;
1123 err:
1124         spin_lock(&wdm_device_list_lock);
1125         list_del(&desc->device_list);
1126         spin_unlock(&wdm_device_list_lock);
1127         cleanup(desc);
1128         return rv;
1129 }
1130
1131 static int wdm_manage_power(struct usb_interface *intf, int on)
1132 {
1133         /* need autopm_get/put here to ensure the usbcore sees the new value */
1134         int rv = usb_autopm_get_interface(intf);
1135
1136         intf->needs_remote_wakeup = on;
1137         if (!rv)
1138                 usb_autopm_put_interface(intf);
1139         return 0;
1140 }
1141
1142 static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
1143 {
1144         int rv = -EINVAL;
1145         struct usb_host_interface *iface;
1146         struct usb_endpoint_descriptor *ep;
1147         struct usb_cdc_parsed_header hdr;
1148         u8 *buffer = intf->altsetting->extra;
1149         int buflen = intf->altsetting->extralen;
1150         u16 maxcom = WDM_DEFAULT_BUFSIZE;
1151
1152         if (!buffer)
1153                 goto err;
1154
1155         cdc_parse_cdc_header(&hdr, intf, buffer, buflen);
1156
1157         if (hdr.usb_cdc_dmm_desc)
1158                 maxcom = le16_to_cpu(hdr.usb_cdc_dmm_desc->wMaxCommand);
1159
1160         iface = intf->cur_altsetting;
1161         if (iface->desc.bNumEndpoints != 1)
1162                 goto err;
1163         ep = &iface->endpoint[0].desc;
1164
1165         rv = wdm_create(intf, ep, maxcom, WWAN_PORT_UNKNOWN, &wdm_manage_power);
1166
1167 err:
1168         return rv;
1169 }
1170
1171 /**
1172  * usb_cdc_wdm_register - register a WDM subdriver
1173  * @intf: usb interface the subdriver will associate with
1174  * @ep: interrupt endpoint to monitor for notifications
1175  * @bufsize: maximum message size to support for read/write
1176  * @type: Type/protocol of the transported data (MBIM, QMI...)
1177  * @manage_power: call-back invoked during open and release to
1178  *                manage the device's power
1179  * Create WDM usb class character device and associate it with intf
1180  * without binding, allowing another driver to manage the interface.
1181  *
1182  * The subdriver will manage the given interrupt endpoint exclusively
1183  * and will issue control requests referring to the given intf. It
1184  * will otherwise avoid interferring, and in particular not do
1185  * usb_set_intfdata/usb_get_intfdata on intf.
1186  *
1187  * The return value is a pointer to the subdriver's struct usb_driver.
1188  * The registering driver is responsible for calling this subdriver's
1189  * disconnect, suspend, resume, pre_reset and post_reset methods from
1190  * its own.
1191  */
1192 struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,
1193                                         struct usb_endpoint_descriptor *ep,
1194                                         int bufsize, enum wwan_port_type type,
1195                                         int (*manage_power)(struct usb_interface *, int))
1196 {
1197         int rv;
1198
1199         rv = wdm_create(intf, ep, bufsize, type, manage_power);
1200         if (rv < 0)
1201                 goto err;
1202
1203         return &wdm_driver;
1204 err:
1205         return ERR_PTR(rv);
1206 }
1207 EXPORT_SYMBOL(usb_cdc_wdm_register);
1208
1209 static void wdm_disconnect(struct usb_interface *intf)
1210 {
1211         struct wdm_device *desc;
1212         unsigned long flags;
1213
1214         usb_deregister_dev(intf, &wdm_class);
1215         desc = wdm_find_device(intf);
1216         mutex_lock(&wdm_mutex);
1217
1218         wdm_wwan_deinit(desc);
1219
1220         /* the spinlock makes sure no new urbs are generated in the callbacks */
1221         spin_lock_irqsave(&desc->iuspin, flags);
1222         set_bit(WDM_DISCONNECTING, &desc->flags);
1223         set_bit(WDM_READ, &desc->flags);
1224         spin_unlock_irqrestore(&desc->iuspin, flags);
1225         wake_up_all(&desc->wait);
1226         mutex_lock(&desc->rlock);
1227         mutex_lock(&desc->wlock);
1228         poison_urbs(desc);
1229         cancel_work_sync(&desc->rxwork);
1230         cancel_work_sync(&desc->service_outs_intr);
1231         mutex_unlock(&desc->wlock);
1232         mutex_unlock(&desc->rlock);
1233
1234         /* the desc->intf pointer used as list key is now invalid */
1235         spin_lock(&wdm_device_list_lock);
1236         list_del(&desc->device_list);
1237         spin_unlock(&wdm_device_list_lock);
1238
1239         if (!desc->count)
1240                 cleanup(desc);
1241         else
1242                 dev_dbg(&intf->dev, "%d open files - postponing cleanup\n", desc->count);
1243         mutex_unlock(&wdm_mutex);
1244 }
1245
1246 #ifdef CONFIG_PM
1247 static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
1248 {
1249         struct wdm_device *desc = wdm_find_device(intf);
1250         int rv = 0;
1251
1252         dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
1253
1254         /* if this is an autosuspend the caller does the locking */
1255         if (!PMSG_IS_AUTO(message)) {
1256                 mutex_lock(&desc->rlock);
1257                 mutex_lock(&desc->wlock);
1258         }
1259         spin_lock_irq(&desc->iuspin);
1260
1261         if (PMSG_IS_AUTO(message) &&
1262                         (test_bit(WDM_IN_USE, &desc->flags)
1263                         || test_bit(WDM_RESPONDING, &desc->flags))) {
1264                 spin_unlock_irq(&desc->iuspin);
1265                 rv = -EBUSY;
1266         } else {
1267
1268                 set_bit(WDM_SUSPENDING, &desc->flags);
1269                 spin_unlock_irq(&desc->iuspin);
1270                 /* callback submits work - order is essential */
1271                 poison_urbs(desc);
1272                 cancel_work_sync(&desc->rxwork);
1273                 cancel_work_sync(&desc->service_outs_intr);
1274                 unpoison_urbs(desc);
1275         }
1276         if (!PMSG_IS_AUTO(message)) {
1277                 mutex_unlock(&desc->wlock);
1278                 mutex_unlock(&desc->rlock);
1279         }
1280
1281         return rv;
1282 }
1283 #endif
1284
1285 static int recover_from_urb_loss(struct wdm_device *desc)
1286 {
1287         int rv = 0;
1288
1289         if (desc->count) {
1290                 rv = usb_submit_urb(desc->validity, GFP_NOIO);
1291                 if (rv < 0)
1292                         dev_err(&desc->intf->dev,
1293                                 "Error resume submitting int urb - %d\n", rv);
1294         }
1295         return rv;
1296 }
1297
1298 #ifdef CONFIG_PM
1299 static int wdm_resume(struct usb_interface *intf)
1300 {
1301         struct wdm_device *desc = wdm_find_device(intf);
1302         int rv;
1303
1304         dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
1305
1306         clear_bit(WDM_SUSPENDING, &desc->flags);
1307         rv = recover_from_urb_loss(desc);
1308
1309         return rv;
1310 }
1311 #endif
1312
1313 static int wdm_pre_reset(struct usb_interface *intf)
1314 {
1315         struct wdm_device *desc = wdm_find_device(intf);
1316
1317         /*
1318          * we notify everybody using poll of
1319          * an exceptional situation
1320          * must be done before recovery lest a spontaneous
1321          * message from the device is lost
1322          */
1323         spin_lock_irq(&desc->iuspin);
1324         set_bit(WDM_RESETTING, &desc->flags);   /* inform read/write */
1325         set_bit(WDM_READ, &desc->flags);        /* unblock read */
1326         clear_bit(WDM_IN_USE, &desc->flags);    /* unblock write */
1327         desc->rerr = -EINTR;
1328         spin_unlock_irq(&desc->iuspin);
1329         wake_up_all(&desc->wait);
1330         mutex_lock(&desc->rlock);
1331         mutex_lock(&desc->wlock);
1332         poison_urbs(desc);
1333         cancel_work_sync(&desc->rxwork);
1334         cancel_work_sync(&desc->service_outs_intr);
1335         return 0;
1336 }
1337
1338 static int wdm_post_reset(struct usb_interface *intf)
1339 {
1340         struct wdm_device *desc = wdm_find_device(intf);
1341         int rv;
1342
1343         unpoison_urbs(desc);
1344         clear_bit(WDM_OVERFLOW, &desc->flags);
1345         clear_bit(WDM_RESETTING, &desc->flags);
1346         rv = recover_from_urb_loss(desc);
1347         mutex_unlock(&desc->wlock);
1348         mutex_unlock(&desc->rlock);
1349         return rv;
1350 }
1351
1352 static struct usb_driver wdm_driver = {
1353         .name =         "cdc_wdm",
1354         .probe =        wdm_probe,
1355         .disconnect =   wdm_disconnect,
1356 #ifdef CONFIG_PM
1357         .suspend =      wdm_suspend,
1358         .resume =       wdm_resume,
1359         .reset_resume = wdm_resume,
1360 #endif
1361         .pre_reset =    wdm_pre_reset,
1362         .post_reset =   wdm_post_reset,
1363         .id_table =     wdm_ids,
1364         .supports_autosuspend = 1,
1365         .disable_hub_initiated_lpm = 1,
1366 };
1367
1368 module_usb_driver(wdm_driver);
1369
1370 MODULE_AUTHOR(DRIVER_AUTHOR);
1371 MODULE_DESCRIPTION(DRIVER_DESC);
1372 MODULE_LICENSE("GPL");