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         int used;
 489
 490         /* submit read urb only if the device is waiting for it */
 491         if (!desc->resp_count || !--desc->resp_count)
 492                 goto out;
 493
 494         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 495                 rv = -ENODEV;
 496                 goto out;
 497         }
 498         if (test_bit(WDM_RESETTING, &desc->flags)) {
 499                 rv = -EIO;
 500                 goto out;
 501         }
 502
 503         used = test_and_set_bit(WDM_RESPONDING, &desc->flags);
 504         if (used)
 505                 goto out;
 506
 507         spin_unlock_irq(&desc->iuspin);
 508         rv = usb_submit_urb(desc->response, GFP_KERNEL);
 509         spin_lock_irq(&desc->iuspin);
 510         if (rv) {
 511                 if (!test_bit(WDM_DISCONNECTING, &desc->flags))
 512                         dev_err(&desc->intf->dev,
 513                                 "usb_submit_urb failed with result %d\n", rv);
 514
 515                 /* make sure the next notification trigger a submit */
 516                 clear_bit(WDM_RESPONDING, &desc->flags);
 517                 desc->resp_count = 0;
 518         }
 519 out:
 520         return rv;
 521 }
 522
 523 static ssize_t wdm_read
 524 (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 525 {
 526         int rv, cntr;
 527         int i = 0;
 528         struct wdm_device *desc = file->private_data;
 529
 530
 531         rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
 532         if (rv < 0)
 533                 return -ERESTARTSYS;
 534
 535         cntr = READ_ONCE(desc->length);
 536         if (cntr == 0) {
 537                 desc->read = 0;
 538 retry:
 539                 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 540                         rv = -ENODEV;
 541                         goto err;
 542                 }
 543                 if (test_bit(WDM_OVERFLOW, &desc->flags)) {
 544                         clear_bit(WDM_OVERFLOW, &desc->flags);
 545                         rv = -ENOBUFS;
 546                         goto err;
 547                 }
 548                 i++;
 549                 if (file->f_flags & O_NONBLOCK) {
 550                         if (!test_bit(WDM_READ, &desc->flags)) {
 551                                 rv = -EAGAIN;
 552                                 goto err;
 553                         }
 554                         rv = 0;
 555                 } else {
 556                         rv = wait_event_interruptible(desc->wait,
 557                                 test_bit(WDM_READ, &desc->flags));
 558                 }
 559
 560                 /* may have happened while we slept */
 561                 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 562                         rv = -ENODEV;
 563                         goto err;
 564                 }
 565                 if (test_bit(WDM_RESETTING, &desc->flags)) {
 566                         rv = -EIO;
 567                         goto err;
 568                 }
 569                 usb_mark_last_busy(interface_to_usbdev(desc->intf));
 570                 if (rv < 0) {
 571                         rv = -ERESTARTSYS;
 572                         goto err;
 573                 }
 574
 575                 spin_lock_irq(&desc->iuspin);
 576
 577                 if (desc->rerr) { /* read completed, error happened */
 578                         rv = usb_translate_errors(desc->rerr);
 579                         desc->rerr = 0;
 580                         spin_unlock_irq(&desc->iuspin);
 581                         goto err;
 582                 }
 583                 /*
 584                  * recheck whether we've lost the race
 585                  * against the completion handler
 586                  */
 587                 if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */
 588                         spin_unlock_irq(&desc->iuspin);
 589                         goto retry;
 590                 }
 591
 592                 if (!desc->reslength) { /* zero length read */
 593                         dev_dbg(&desc->intf->dev, "zero length - clearing WDM_READ\n");
 594                         clear_bit(WDM_READ, &desc->flags);
 595                         rv = service_outstanding_interrupt(desc);
 596                         spin_unlock_irq(&desc->iuspin);
 597                         if (rv < 0)
 598                                 goto err;
 599                         goto retry;
 600                 }
 601                 cntr = desc->length;
 602                 spin_unlock_irq(&desc->iuspin);
 603         }
 604
 605         if (cntr > count)
 606                 cntr = count;
 607         rv = copy_to_user(buffer, desc->ubuf, cntr);
 608         if (rv > 0) {
 609                 rv = -EFAULT;
 610                 goto err;
 611         }
 612
 613         spin_lock_irq(&desc->iuspin);
 614
 615         for (i = 0; i < desc->length - cntr; i++)
 616                 desc->ubuf[i] = desc->ubuf[i + cntr];
 617
 618         desc->length -= cntr;
 619         /* in case we had outstanding data */
 620         if (!desc->length) {
 621                 clear_bit(WDM_READ, &desc->flags);
 622                 service_outstanding_interrupt(desc);
 623         }
 624         spin_unlock_irq(&desc->iuspin);
 625         rv = cntr;
 626
 627 err:
 628         mutex_unlock(&desc->rlock);
 629         return rv;
 630 }
 631
 632 static int wdm_wait_for_response(struct file *file, long timeout)
 633 {
 634         struct wdm_device *desc = file->private_data;
 635         long rv; /* Use long here because (int) MAX_SCHEDULE_TIMEOUT < 0. */
 636
 637         /*
 638          * Needs both flags. We cannot do with one because resetting it would
 639          * cause a race with write() yet we need to signal a disconnect.
 640          */
 641         rv = wait_event_interruptible_timeout(desc->wait,
 642                               !test_bit(WDM_IN_USE, &desc->flags) ||
 643                               test_bit(WDM_DISCONNECTING, &desc->flags),
 644                               timeout);
 645
 646         /*
 647          * To report the correct error. This is best effort.
 648          * We are inevitably racing with the hardware.
 649          */
 650         if (test_bit(WDM_DISCONNECTING, &desc->flags))
 651                 return -ENODEV;
 652         if (!rv)
 653                 return -EIO;
 654         if (rv < 0)
 655                 return -EINTR;
 656
 657         spin_lock_irq(&desc->iuspin);
 658         rv = desc->werr;
 659         desc->werr = 0;
 660         spin_unlock_irq(&desc->iuspin);
 661
 662         return usb_translate_errors(rv);
 663
 664 }
 665
 666 /*
 667  * You need to send a signal when you react to malicious or defective hardware.
 668  * Also, don't abort when fsync() returned -EINVAL, for older kernels which do
 669  * not implement wdm_flush() will return -EINVAL.
 670  */
 671 static int wdm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 672 {
 673         return wdm_wait_for_response(file, MAX_SCHEDULE_TIMEOUT);
 674 }
 675
 676 /*
 677  * Same with wdm_fsync(), except it uses finite timeout in order to react to
 678  * malicious or defective hardware which ceased communication after close() was
 679  * implicitly called due to process termination.
 680  */
 681 static int wdm_flush(struct file *file, fl_owner_t id)
 682 {
 683         return wdm_wait_for_response(file, WDM_FLUSH_TIMEOUT);
 684 }
 685
 686 static __poll_t wdm_poll(struct file *file, struct poll_table_struct *wait)
 687 {
 688         struct wdm_device *desc = file->private_data;
 689         unsigned long flags;
 690         __poll_t mask = 0;
 691
 692         spin_lock_irqsave(&desc->iuspin, flags);
 693         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 694                 mask = EPOLLHUP | EPOLLERR;
 695                 spin_unlock_irqrestore(&desc->iuspin, flags);
 696                 goto desc_out;
 697         }
 698         if (test_bit(WDM_READ, &desc->flags))
 699                 mask = EPOLLIN | EPOLLRDNORM;
 700         if (desc->rerr || desc->werr)
 701                 mask |= EPOLLERR;
 702         if (!test_bit(WDM_IN_USE, &desc->flags))
 703                 mask |= EPOLLOUT | EPOLLWRNORM;
 704         spin_unlock_irqrestore(&desc->iuspin, flags);
 705
 706         poll_wait(file, &desc->wait, wait);
 707
 708 desc_out:
 709         return mask;
 710 }
 711
 712 static int wdm_open(struct inode *inode, struct file *file)
 713 {
 714         int minor = iminor(inode);
 715         int rv = -ENODEV;
 716         struct usb_interface *intf;
 717         struct wdm_device *desc;
 718
 719         mutex_lock(&wdm_mutex);
 720         desc = wdm_find_device_by_minor(minor);
 721         if (!desc)
 722                 goto out;
 723
 724         intf = desc->intf;
 725         if (test_bit(WDM_DISCONNECTING, &desc->flags))
 726                 goto out;
 727         file->private_data = desc;
 728
 729         if (test_bit(WDM_WWAN_IN_USE, &desc->flags)) {
 730                 rv = -EBUSY;
 731                 goto out;
 732         }
 733
 734         rv = usb_autopm_get_interface(desc->intf);
 735         if (rv < 0) {
 736                 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
 737                 goto out;
 738         }
 739
 740         /* using write lock to protect desc->count */
 741         mutex_lock(&desc->wlock);
 742         if (!desc->count++) {
 743                 desc->werr = 0;
 744                 desc->rerr = 0;
 745                 rv = usb_submit_urb(desc->validity, GFP_KERNEL);
 746                 if (rv < 0) {
 747                         desc->count--;
 748                         dev_err(&desc->intf->dev,
 749                                 "Error submitting int urb - %d\n", rv);
 750                         rv = usb_translate_errors(rv);
 751                 }
 752         } else {
 753                 rv = 0;
 754         }
 755         mutex_unlock(&desc->wlock);
 756         if (desc->count == 1)
 757                 desc->manage_power(intf, 1);
 758         usb_autopm_put_interface(desc->intf);
 759 out:
 760         mutex_unlock(&wdm_mutex);
 761         return rv;
 762 }
 763
 764 static int wdm_release(struct inode *inode, struct file *file)
 765 {
 766         struct wdm_device *desc = file->private_data;
 767
 768         mutex_lock(&wdm_mutex);
 769
 770         /* using write lock to protect desc->count */
 771         mutex_lock(&desc->wlock);
 772         desc->count--;
 773         mutex_unlock(&desc->wlock);
 774
 775         if (!desc->count) {
 776                 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
 777                         dev_dbg(&desc->intf->dev, "wdm_release: cleanup\n");
 778                         poison_urbs(desc);
 779                         spin_lock_irq(&desc->iuspin);
 780                         desc->resp_count = 0;
 781                         clear_bit(WDM_RESPONDING, &desc->flags);
 782                         spin_unlock_irq(&desc->iuspin);
 783                         desc->manage_power(desc->intf, 0);
 784                         unpoison_urbs(desc);
 785                 } else {
 786                         /* must avoid dev_printk here as desc->intf is invalid */
 787                         pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
 788                         cleanup(desc);
 789                 }
 790         }
 791         mutex_unlock(&wdm_mutex);
 792         return 0;
 793 }
 794
 795 static long wdm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 796 {
 797         struct wdm_device *desc = file->private_data;
 798         int rv = 0;
 799
 800         switch (cmd) {
 801         case IOCTL_WDM_MAX_COMMAND:
 802                 if (copy_to_user((void __user *)arg, &desc->wMaxCommand, sizeof(desc->wMaxCommand)))
 803                         rv = -EFAULT;
 804                 break;
 805         default:
 806                 rv = -ENOTTY;
 807         }
 808         return rv;
 809 }
 810
 811 static const struct file_operations wdm_fops = {
 812         .owner =        THIS_MODULE,
 813         .read =         wdm_read,
 814         .write =        wdm_write,
 815         .fsync =        wdm_fsync,
 816         .open =         wdm_open,
 817         .flush =        wdm_flush,
 818         .release =      wdm_release,
 819         .poll =         wdm_poll,
 820         .unlocked_ioctl = wdm_ioctl,
 821         .compat_ioctl = compat_ptr_ioctl,
 822         .llseek =       noop_llseek,
 823 };
 824
 825 static struct usb_class_driver wdm_class = {
 826         .name =         "cdc-wdm%d",
 827         .fops =         &wdm_fops,
 828         .minor_base =   WDM_MINOR_BASE,
 829 };
 830
 831 /* --- WWAN framework integration --- */
 832 #ifdef CONFIG_WWAN
 833 static int wdm_wwan_port_start(struct wwan_port *port)
 834 {
 835         struct wdm_device *desc = wwan_port_get_drvdata(port);
 836
 837         /* The interface is both exposed via the WWAN framework and as a
 838          * legacy usbmisc chardev. If chardev is already open, just fail
 839          * to prevent concurrent usage. Otherwise, switch to WWAN mode.
 840          */
 841         mutex_lock(&wdm_mutex);
 842         if (desc->count) {
 843                 mutex_unlock(&wdm_mutex);
 844                 return -EBUSY;
 845         }
 846         set_bit(WDM_WWAN_IN_USE, &desc->flags);
 847         mutex_unlock(&wdm_mutex);
 848
 849         desc->manage_power(desc->intf, 1);
 850
 851         /* tx is allowed */
 852         wwan_port_txon(port);
 853
 854         /* Start getting events */
 855         return usb_submit_urb(desc->validity, GFP_KERNEL);
 856 }
 857
 858 static void wdm_wwan_port_stop(struct wwan_port *port)
 859 {
 860         struct wdm_device *desc = wwan_port_get_drvdata(port);
 861
 862         /* Stop all transfers and disable WWAN mode */
 863         poison_urbs(desc);
 864         desc->manage_power(desc->intf, 0);
 865         clear_bit(WDM_READ, &desc->flags);
 866         clear_bit(WDM_WWAN_IN_USE, &desc->flags);
 867         unpoison_urbs(desc);
 868 }
 869
 870 static void wdm_wwan_port_tx_complete(struct urb *urb)
 871 {
 872         struct sk_buff *skb = urb->context;
 873         struct wdm_device *desc = skb_shinfo(skb)->destructor_arg;
 874
 875         usb_autopm_put_interface(desc->intf);
 876         wwan_port_txon(desc->wwanp);
 877         kfree_skb(skb);
 878 }
 879
 880 static int wdm_wwan_port_tx(struct wwan_port *port, struct sk_buff *skb)
 881 {
 882         struct wdm_device *desc = wwan_port_get_drvdata(port);
 883         struct usb_interface *intf = desc->intf;
 884         struct usb_ctrlrequest *req = desc->orq;
 885         int rv;
 886
 887         rv = usb_autopm_get_interface(intf);
 888         if (rv)
 889                 return rv;
 890
 891         usb_fill_control_urb(
 892                 desc->command,
 893                 interface_to_usbdev(intf),
 894                 usb_sndctrlpipe(interface_to_usbdev(intf), 0),
 895                 (unsigned char *)req,
 896                 skb->data,
 897                 skb->len,
 898                 wdm_wwan_port_tx_complete,
 899                 skb
 900         );
 901
 902         req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
 903         req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
 904         req->wValue = 0;
 905         req->wIndex = desc->inum;
 906         req->wLength = cpu_to_le16(skb->len);
 907
 908         skb_shinfo(skb)->destructor_arg = desc;
 909
 910         rv = usb_submit_urb(desc->command, GFP_KERNEL);
 911         if (rv)
 912                 usb_autopm_put_interface(intf);
 913         else /* One transfer at a time, stop TX until URB completion */
 914                 wwan_port_txoff(port);
 915
 916         return rv;
 917 }
 918
 919 static const struct wwan_port_ops wdm_wwan_port_ops = {
 920         .start = wdm_wwan_port_start,
 921         .stop = wdm_wwan_port_stop,
 922         .tx = wdm_wwan_port_tx,
 923 };
 924
 925 static void wdm_wwan_init(struct wdm_device *desc)
 926 {
 927         struct usb_interface *intf = desc->intf;
 928         struct wwan_port *port;
 929
 930         /* Only register to WWAN core if protocol/type is known */
 931         if (desc->wwanp_type == WWAN_PORT_UNKNOWN) {
 932                 dev_info(&intf->dev, "Unknown control protocol\n");
 933                 return;
 934         }
 935
 936         port = wwan_create_port(&intf->dev, desc->wwanp_type, &wdm_wwan_port_ops,
 937                                 NULL, desc);
 938         if (IS_ERR(port)) {
 939                 dev_err(&intf->dev, "%s: Unable to create WWAN port\n",
 940                         dev_name(intf->usb_dev));
 941                 return;
 942         }
 943
 944         desc->wwanp = port;
 945 }
 946
 947 static void wdm_wwan_deinit(struct wdm_device *desc)
 948 {
 949         if (!desc->wwanp)
 950                 return;
 951
 952         wwan_remove_port(desc->wwanp);
 953         desc->wwanp = NULL;
 954 }
 955
 956 static void wdm_wwan_rx(struct wdm_device *desc, int length)
 957 {
 958         struct wwan_port *port = desc->wwanp;
 959         struct sk_buff *skb;
 960
 961         /* Forward data to WWAN port */
 962         skb = alloc_skb(length, GFP_ATOMIC);
 963         if (!skb)
 964                 return;
 965
 966         skb_put_data(skb, desc->inbuf, length);
 967         wwan_port_rx(port, skb);
 968
 969         /* inbuf has been copied, it is safe to check for outstanding data */
 970         schedule_work(&desc->service_outs_intr);
 971 }
 972 #else /* CONFIG_WWAN */
 973 static void wdm_wwan_init(struct wdm_device *desc) {}
 974 static void wdm_wwan_deinit(struct wdm_device *desc) {}
 975 static void wdm_wwan_rx(struct wdm_device *desc, int length) {}
 976 #endif /* CONFIG_WWAN */
 977
 978 /* --- error handling --- */
 979 static void wdm_rxwork(struct work_struct *work)
 980 {
 981         struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
 982         unsigned long flags;
 983         int rv = 0;
 984         int responding;
 985
 986         spin_lock_irqsave(&desc->iuspin, flags);
 987         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 988                 spin_unlock_irqrestore(&desc->iuspin, flags);
 989         } else {
 990                 responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
 991                 spin_unlock_irqrestore(&desc->iuspin, flags);
 992                 if (!responding)
 993                         rv = usb_submit_urb(desc->response, GFP_KERNEL);
 994                 if (rv < 0 && rv != -EPERM) {
 995                         spin_lock_irqsave(&desc->iuspin, flags);
 996                         clear_bit(WDM_RESPONDING, &desc->flags);
 997                         if (!test_bit(WDM_DISCONNECTING, &desc->flags))
 998                                 schedule_work(&desc->rxwork);
 999                         spin_unlock_irqrestore(&desc->iuspin, flags);
1000                 }
1001         }
1002 }
1003
1004 static void service_interrupt_work(struct work_struct *work)
1005 {
1006         struct wdm_device *desc;
1007
1008         desc = container_of(work, struct wdm_device, service_outs_intr);
1009
1010         spin_lock_irq(&desc->iuspin);
1011         service_outstanding_interrupt(desc);
1012         if (!desc->resp_count) {
1013                 set_bit(WDM_READ, &desc->flags);
1014                 wake_up(&desc->wait);
1015         }
1016         spin_unlock_irq(&desc->iuspin);
1017 }
1018
1019 /* --- hotplug --- */
1020
1021 static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
1022                       u16 bufsize, enum wwan_port_type type,
1023                       int (*manage_power)(struct usb_interface *, int))
1024 {
1025         int rv = -ENOMEM;
1026         struct wdm_device *desc;
1027
1028         desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
1029         if (!desc)
1030                 goto out;
1031         INIT_LIST_HEAD(&desc->device_list);
1032         mutex_init(&desc->rlock);
1033         mutex_init(&desc->wlock);
1034         spin_lock_init(&desc->iuspin);
1035         init_waitqueue_head(&desc->wait);
1036         desc->wMaxCommand = bufsize;
1037         /* this will be expanded and needed in hardware endianness */
1038         desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
1039         desc->intf = intf;
1040         desc->wwanp_type = type;
1041         INIT_WORK(&desc->rxwork, wdm_rxwork);
1042         INIT_WORK(&desc->service_outs_intr, service_interrupt_work);
1043
1044         if (!usb_endpoint_is_int_in(ep)) {
1045                 rv = -EINVAL;
1046                 goto err;
1047         }
1048
1049         desc->wMaxPacketSize = usb_endpoint_maxp(ep);
1050
1051         desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
1052         if (!desc->orq)
1053                 goto err;
1054         desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
1055         if (!desc->irq)
1056                 goto err;
1057
1058         desc->validity = usb_alloc_urb(0, GFP_KERNEL);
1059         if (!desc->validity)
1060                 goto err;
1061
1062         desc->response = usb_alloc_urb(0, GFP_KERNEL);
1063         if (!desc->response)
1064                 goto err;
1065
1066         desc->command = usb_alloc_urb(0, GFP_KERNEL);
1067         if (!desc->command)
1068                 goto err;
1069
1070         desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
1071         if (!desc->ubuf)
1072                 goto err;
1073
1074         desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);
1075         if (!desc->sbuf)
1076                 goto err;
1077
1078         desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
1079         if (!desc->inbuf)
1080                 goto err;
1081
1082         usb_fill_int_urb(
1083                 desc->validity,
1084                 interface_to_usbdev(intf),
1085                 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
1086                 desc->sbuf,
1087                 desc->wMaxPacketSize,
1088                 wdm_int_callback,
1089                 desc,
1090                 ep->bInterval
1091         );
1092
1093         desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
1094         desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
1095         desc->irq->wValue = 0;
1096         desc->irq->wIndex = desc->inum; /* already converted */
1097         desc->irq->wLength = cpu_to_le16(desc->wMaxCommand);
1098
1099         usb_fill_control_urb(
1100                 desc->response,
1101                 interface_to_usbdev(intf),
1102                 /* using common endpoint 0 */
1103                 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
1104                 (unsigned char *)desc->irq,
1105                 desc->inbuf,
1106                 desc->wMaxCommand,
1107                 wdm_in_callback,
1108                 desc
1109         );
1110
1111         desc->manage_power = manage_power;
1112
1113         spin_lock(&wdm_device_list_lock);
1114         list_add(&desc->device_list, &wdm_device_list);
1115         spin_unlock(&wdm_device_list_lock);
1116
1117         rv = usb_register_dev(intf, &wdm_class);
1118         if (rv < 0)
1119                 goto err;
1120         else
1121                 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev));
1122
1123         wdm_wwan_init(desc);
1124
1125 out:
1126         return rv;
1127 err:
1128         spin_lock(&wdm_device_list_lock);
1129         list_del(&desc->device_list);
1130         spin_unlock(&wdm_device_list_lock);
1131         cleanup(desc);
1132         return rv;
1133 }
1134
1135 static int wdm_manage_power(struct usb_interface *intf, int on)
1136 {
1137         /* need autopm_get/put here to ensure the usbcore sees the new value */
1138         int rv = usb_autopm_get_interface(intf);
1139
1140         intf->needs_remote_wakeup = on;
1141         if (!rv)
1142                 usb_autopm_put_interface(intf);
1143         return 0;
1144 }
1145
1146 static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
1147 {
1148         int rv = -EINVAL;
1149         struct usb_host_interface *iface;
1150         struct usb_endpoint_descriptor *ep;
1151         struct usb_cdc_parsed_header hdr;
1152         u8 *buffer = intf->altsetting->extra;
1153         int buflen = intf->altsetting->extralen;
1154         u16 maxcom = WDM_DEFAULT_BUFSIZE;
1155
1156         if (!buffer)
1157                 goto err;
1158
1159         cdc_parse_cdc_header(&hdr, intf, buffer, buflen);
1160
1161         if (hdr.usb_cdc_dmm_desc)
1162                 maxcom = le16_to_cpu(hdr.usb_cdc_dmm_desc->wMaxCommand);
1163
1164         iface = intf->cur_altsetting;
1165         if (iface->desc.bNumEndpoints != 1)
1166                 goto err;
1167         ep = &iface->endpoint[0].desc;
1168
1169         rv = wdm_create(intf, ep, maxcom, WWAN_PORT_UNKNOWN, &wdm_manage_power);
1170
1171 err:
1172         return rv;
1173 }
1174
1175 /**
1176  * usb_cdc_wdm_register - register a WDM subdriver
1177  * @intf: usb interface the subdriver will associate with
1178  * @ep: interrupt endpoint to monitor for notifications
1179  * @bufsize: maximum message size to support for read/write
1180  * @type: Type/protocol of the transported data (MBIM, QMI...)
1181  * @manage_power: call-back invoked during open and release to
1182  *                manage the device's power
1183  * Create WDM usb class character device and associate it with intf
1184  * without binding, allowing another driver to manage the interface.
1185  *
1186  * The subdriver will manage the given interrupt endpoint exclusively
1187  * and will issue control requests referring to the given intf. It
1188  * will otherwise avoid interferring, and in particular not do
1189  * usb_set_intfdata/usb_get_intfdata on intf.
1190  *
1191  * The return value is a pointer to the subdriver's struct usb_driver.
1192  * The registering driver is responsible for calling this subdriver's
1193  * disconnect, suspend, resume, pre_reset and post_reset methods from
1194  * its own.
1195  */
1196 struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,
1197                                         struct usb_endpoint_descriptor *ep,
1198                                         int bufsize, enum wwan_port_type type,
1199                                         int (*manage_power)(struct usb_interface *, int))
1200 {
1201         int rv;
1202
1203         rv = wdm_create(intf, ep, bufsize, type, manage_power);
1204         if (rv < 0)
1205                 goto err;
1206
1207         return &wdm_driver;
1208 err:
1209         return ERR_PTR(rv);
1210 }
1211 EXPORT_SYMBOL(usb_cdc_wdm_register);
1212
1213 static void wdm_disconnect(struct usb_interface *intf)
1214 {
1215         struct wdm_device *desc;
1216         unsigned long flags;
1217
1218         usb_deregister_dev(intf, &wdm_class);
1219         desc = wdm_find_device(intf);
1220         mutex_lock(&wdm_mutex);
1221
1222         wdm_wwan_deinit(desc);
1223
1224         /* the spinlock makes sure no new urbs are generated in the callbacks */
1225         spin_lock_irqsave(&desc->iuspin, flags);
1226         set_bit(WDM_DISCONNECTING, &desc->flags);
1227         set_bit(WDM_READ, &desc->flags);
1228         spin_unlock_irqrestore(&desc->iuspin, flags);
1229         wake_up_all(&desc->wait);
1230         mutex_lock(&desc->rlock);
1231         mutex_lock(&desc->wlock);
1232         poison_urbs(desc);
1233         cancel_work_sync(&desc->rxwork);
1234         cancel_work_sync(&desc->service_outs_intr);
1235         mutex_unlock(&desc->wlock);
1236         mutex_unlock(&desc->rlock);
1237
1238         /* the desc->intf pointer used as list key is now invalid */
1239         spin_lock(&wdm_device_list_lock);
1240         list_del(&desc->device_list);
1241         spin_unlock(&wdm_device_list_lock);
1242
1243         if (!desc->count)
1244                 cleanup(desc);
1245         else
1246                 dev_dbg(&intf->dev, "%d open files - postponing cleanup\n", desc->count);
1247         mutex_unlock(&wdm_mutex);
1248 }
1249
1250 #ifdef CONFIG_PM
1251 static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
1252 {
1253         struct wdm_device *desc = wdm_find_device(intf);
1254         int rv = 0;
1255
1256         dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
1257
1258         /* if this is an autosuspend the caller does the locking */
1259         if (!PMSG_IS_AUTO(message)) {
1260                 mutex_lock(&desc->rlock);
1261                 mutex_lock(&desc->wlock);
1262         }
1263         spin_lock_irq(&desc->iuspin);
1264
1265         if (PMSG_IS_AUTO(message) &&
1266                         (test_bit(WDM_IN_USE, &desc->flags)
1267                         || test_bit(WDM_RESPONDING, &desc->flags))) {
1268                 spin_unlock_irq(&desc->iuspin);
1269                 rv = -EBUSY;
1270         } else {
1271
1272                 set_bit(WDM_SUSPENDING, &desc->flags);
1273                 spin_unlock_irq(&desc->iuspin);
1274                 /* callback submits work - order is essential */
1275                 poison_urbs(desc);
1276                 cancel_work_sync(&desc->rxwork);
1277                 cancel_work_sync(&desc->service_outs_intr);
1278                 unpoison_urbs(desc);
1279         }
1280         if (!PMSG_IS_AUTO(message)) {
1281                 mutex_unlock(&desc->wlock);
1282                 mutex_unlock(&desc->rlock);
1283         }
1284
1285         return rv;
1286 }
1287 #endif
1288
1289 static int recover_from_urb_loss(struct wdm_device *desc)
1290 {
1291         int rv = 0;
1292
1293         if (desc->count) {
1294                 rv = usb_submit_urb(desc->validity, GFP_NOIO);
1295                 if (rv < 0)
1296                         dev_err(&desc->intf->dev,
1297                                 "Error resume submitting int urb - %d\n", rv);
1298         }
1299         return rv;
1300 }
1301
1302 #ifdef CONFIG_PM
1303 static int wdm_resume(struct usb_interface *intf)
1304 {
1305         struct wdm_device *desc = wdm_find_device(intf);
1306         int rv;
1307
1308         dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
1309
1310         clear_bit(WDM_SUSPENDING, &desc->flags);
1311         rv = recover_from_urb_loss(desc);
1312
1313         return rv;
1314 }
1315 #endif
1316
1317 static int wdm_pre_reset(struct usb_interface *intf)
1318 {
1319         struct wdm_device *desc = wdm_find_device(intf);
1320
1321         /*
1322          * we notify everybody using poll of
1323          * an exceptional situation
1324          * must be done before recovery lest a spontaneous
1325          * message from the device is lost
1326          */
1327         spin_lock_irq(&desc->iuspin);
1328         set_bit(WDM_RESETTING, &desc->flags);   /* inform read/write */
1329         set_bit(WDM_READ, &desc->flags);        /* unblock read */
1330         clear_bit(WDM_IN_USE, &desc->flags);    /* unblock write */
1331         desc->rerr = -EINTR;
1332         spin_unlock_irq(&desc->iuspin);
1333         wake_up_all(&desc->wait);
1334         mutex_lock(&desc->rlock);
1335         mutex_lock(&desc->wlock);
1336         poison_urbs(desc);
1337         cancel_work_sync(&desc->rxwork);
1338         cancel_work_sync(&desc->service_outs_intr);
1339         return 0;
1340 }
1341
1342 static int wdm_post_reset(struct usb_interface *intf)
1343 {
1344         struct wdm_device *desc = wdm_find_device(intf);
1345         int rv;
1346
1347         unpoison_urbs(desc);
1348         clear_bit(WDM_OVERFLOW, &desc->flags);
1349         clear_bit(WDM_RESETTING, &desc->flags);
1350         rv = recover_from_urb_loss(desc);
1351         mutex_unlock(&desc->wlock);
1352         mutex_unlock(&desc->rlock);
1353         return rv;
1354 }
1355
1356 static struct usb_driver wdm_driver = {
1357         .name =         "cdc_wdm",
1358         .probe =        wdm_probe,
1359         .disconnect =   wdm_disconnect,
1360 #ifdef CONFIG_PM
1361         .suspend =      wdm_suspend,
1362         .resume =       wdm_resume,
1363         .reset_resume = wdm_resume,
1364 #endif
1365         .pre_reset =    wdm_pre_reset,
1366         .post_reset =   wdm_post_reset,
1367         .id_table =     wdm_ids,
1368         .supports_autosuspend = 1,
1369         .disable_hub_initiated_lpm = 1,
1370 };
1371
1372 module_usb_driver(wdm_driver);
1373
1374 MODULE_AUTHOR(DRIVER_AUTHOR);
1375 MODULE_DESCRIPTION(DRIVER_DESC);
1376 MODULE_LICENSE("GPL");