drivers/usb/class/cdc-wdm.c

   1 /*
   2  * cdc-wdm.c
   3  *
   4  * This driver supports USB CDC WCM Device Management.
   5  *
   6  * Copyright (c) 2007-2009 Oliver Neukum
   7  *
   8  * Some code taken from cdc-acm.c
   9  *
  10  * Released under the GPLv2.
  11  *
  12  * Many thanks to Carl Nordbeck
  13  */
  14 #include <linux/kernel.h>
  15 #include <linux/errno.h>
  16 #include <linux/ioctl.h>
  17 #include <linux/slab.h>
  18 #include <linux/module.h>
  19 #include <linux/mutex.h>
  20 #include <linux/uaccess.h>
  21 #include <linux/bitops.h>
  22 #include <linux/poll.h>
  23 #include <linux/usb.h>
  24 #include <linux/usb/cdc.h>
  25 #include <asm/byteorder.h>
  26 #include <asm/unaligned.h>
  27 #include <linux/usb/cdc-wdm.h>
  28
  29 /*
  30  * Version Information
  31  */
  32 #define DRIVER_VERSION "v0.03"
  33 #define DRIVER_AUTHOR "Oliver Neukum"
  34 #define DRIVER_DESC "USB Abstract Control Model driver for USB WCM Device Management"
  35
  36 static const struct usb_device_id wdm_ids[] = {
  37         {
  38                 .match_flags = USB_DEVICE_ID_MATCH_INT_CLASS |
  39                                  USB_DEVICE_ID_MATCH_INT_SUBCLASS,
  40                 .bInterfaceClass = USB_CLASS_COMM,
  41                 .bInterfaceSubClass = USB_CDC_SUBCLASS_DMM
  42         },
  43         { }
  44 };
  45
  46 MODULE_DEVICE_TABLE (usb, wdm_ids);
  47
  48 #define WDM_MINOR_BASE  176
  49
  50
  51 #define WDM_IN_USE              1
  52 #define WDM_DISCONNECTING       2
  53 #define WDM_RESULT              3
  54 #define WDM_READ                4
  55 #define WDM_INT_STALL           5
  56 #define WDM_POLL_RUNNING        6
  57 #define WDM_RESPONDING          7
  58 #define WDM_SUSPENDING          8
  59 #define WDM_RESETTING           9
  60 #define WDM_OVERFLOW            10
  61
  62 #define WDM_MAX                 16
  63
  64 /* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */
  65 #define WDM_DEFAULT_BUFSIZE     256
  66
  67 static DEFINE_MUTEX(wdm_mutex);
  68 static DEFINE_SPINLOCK(wdm_device_list_lock);
  69 static LIST_HEAD(wdm_device_list);
  70
  71 /* --- method tables --- */
  72
  73 struct wdm_device {
  74         u8                      *inbuf; /* buffer for response */
  75         u8                      *outbuf; /* buffer for command */
  76         u8                      *sbuf; /* buffer for status */
  77         u8                      *ubuf; /* buffer for copy to user space */
  78
  79         struct urb              *command;
  80         struct urb              *response;
  81         struct urb              *validity;
  82         struct usb_interface    *intf;
  83         struct usb_ctrlrequest  *orq;
  84         struct usb_ctrlrequest  *irq;
  85         spinlock_t              iuspin;
  86
  87         unsigned long           flags;
  88         u16                     bufsize;
  89         u16                     wMaxCommand;
  90         u16                     wMaxPacketSize;
  91         __le16                  inum;
  92         int                     reslength;
  93         int                     length;
  94         int                     read;
  95         int                     count;
  96         dma_addr_t              shandle;
  97         dma_addr_t              ihandle;
  98         struct mutex            wlock;
  99         struct mutex            rlock;
 100         wait_queue_head_t       wait;
 101         struct work_struct      rxwork;
 102         int                     werr;
 103         int                     rerr;
 104         int                     resp_count;
 105
 106         struct list_head        device_list;
 107         int                     (*manage_power)(struct usb_interface *, int);
 108 };
 109
 110 static struct usb_driver wdm_driver;
 111
 112 /* return intfdata if we own the interface, else look up intf in the list */
 113 static struct wdm_device *wdm_find_device(struct usb_interface *intf)
 114 {
 115         struct wdm_device *desc;
 116
 117         spin_lock(&wdm_device_list_lock);
 118         list_for_each_entry(desc, &wdm_device_list, device_list)
 119                 if (desc->intf == intf)
 120                         goto found;
 121         desc = NULL;
 122 found:
 123         spin_unlock(&wdm_device_list_lock);
 124
 125         return desc;
 126 }
 127
 128 static struct wdm_device *wdm_find_device_by_minor(int minor)
 129 {
 130         struct wdm_device *desc;
 131
 132         spin_lock(&wdm_device_list_lock);
 133         list_for_each_entry(desc, &wdm_device_list, device_list)
 134                 if (desc->intf->minor == minor)
 135                         goto found;
 136         desc = NULL;
 137 found:
 138         spin_unlock(&wdm_device_list_lock);
 139
 140         return desc;
 141 }
 142
 143 /* --- callbacks --- */
 144 static void wdm_out_callback(struct urb *urb)
 145 {
 146         struct wdm_device *desc;
 147         desc = urb->context;
 148         spin_lock(&desc->iuspin);
 149         desc->werr = urb->status;
 150         spin_unlock(&desc->iuspin);
 151         kfree(desc->outbuf);
 152         desc->outbuf = NULL;
 153         clear_bit(WDM_IN_USE, &desc->flags);
 154         wake_up(&desc->wait);
 155 }
 156
 157 static void wdm_in_callback(struct urb *urb)
 158 {
 159         struct wdm_device *desc = urb->context;
 160         int status = urb->status;
 161         int length = urb->actual_length;
 162
 163         spin_lock(&desc->iuspin);
 164         clear_bit(WDM_RESPONDING, &desc->flags);
 165
 166         if (status) {
 167                 switch (status) {
 168                 case -ENOENT:
 169                         dev_dbg(&desc->intf->dev,
 170                                 "nonzero urb status received: -ENOENT");
 171                         goto skip_error;
 172                 case -ECONNRESET:
 173                         dev_dbg(&desc->intf->dev,
 174                                 "nonzero urb status received: -ECONNRESET");
 175                         goto skip_error;
 176                 case -ESHUTDOWN:
 177                         dev_dbg(&desc->intf->dev,
 178                                 "nonzero urb status received: -ESHUTDOWN");
 179                         goto skip_error;
 180                 case -EPIPE:
 181                         dev_err(&desc->intf->dev,
 182                                 "nonzero urb status received: -EPIPE\n");
 183                         break;
 184                 default:
 185                         dev_err(&desc->intf->dev,
 186                                 "Unexpected error %d\n", status);
 187                         break;
 188                 }
 189         }
 190
 191         desc->rerr = status;
 192         if (length + desc->length > desc->wMaxCommand) {
 193                 /* The buffer would overflow */
 194                 set_bit(WDM_OVERFLOW, &desc->flags);
 195         } else {
 196                 /* we may already be in overflow */
 197                 if (!test_bit(WDM_OVERFLOW, &desc->flags)) {
 198                         memmove(desc->ubuf + desc->length, desc->inbuf, length);
 199                         desc->length += length;
 200                         desc->reslength = length;
 201                 }
 202         }
 203 skip_error:
 204         wake_up(&desc->wait);
 205
 206         set_bit(WDM_READ, &desc->flags);
 207         spin_unlock(&desc->iuspin);
 208 }
 209
 210 static void wdm_int_callback(struct urb *urb)
 211 {
 212         int rv = 0;
 213         int responding;
 214         int status = urb->status;
 215         struct wdm_device *desc;
 216         struct usb_cdc_notification *dr;
 217
 218         desc = urb->context;
 219         dr = (struct usb_cdc_notification *)desc->sbuf;
 220
 221         if (status) {
 222                 switch (status) {
 223                 case -ESHUTDOWN:
 224                 case -ENOENT:
 225                 case -ECONNRESET:
 226                         return; /* unplug */
 227                 case -EPIPE:
 228                         set_bit(WDM_INT_STALL, &desc->flags);
 229                         dev_err(&desc->intf->dev, "Stall on int endpoint\n");
 230                         goto sw; /* halt is cleared in work */
 231                 default:
 232                         dev_err(&desc->intf->dev,
 233                                 "nonzero urb status received: %d\n", status);
 234                         break;
 235                 }
 236         }
 237
 238         if (urb->actual_length < sizeof(struct usb_cdc_notification)) {
 239                 dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n",
 240                         urb->actual_length);
 241                 goto exit;
 242         }
 243
 244         switch (dr->bNotificationType) {
 245         case USB_CDC_NOTIFY_RESPONSE_AVAILABLE:
 246                 dev_dbg(&desc->intf->dev,
 247                         "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d",
 248                         le16_to_cpu(dr->wIndex), le16_to_cpu(dr->wLength));
 249                 break;
 250
 251         case USB_CDC_NOTIFY_NETWORK_CONNECTION:
 252
 253                 dev_dbg(&desc->intf->dev,
 254                         "NOTIFY_NETWORK_CONNECTION %s network",
 255                         dr->wValue ? "connected to" : "disconnected from");
 256                 goto exit;
 257         case USB_CDC_NOTIFY_SPEED_CHANGE:
 258                 dev_dbg(&desc->intf->dev, "SPEED_CHANGE received (len %u)",
 259                         urb->actual_length);
 260                 goto exit;
 261         default:
 262                 clear_bit(WDM_POLL_RUNNING, &desc->flags);
 263                 dev_err(&desc->intf->dev,
 264                         "unknown notification %d received: index %d len %d\n",
 265                         dr->bNotificationType,
 266                         le16_to_cpu(dr->wIndex),
 267                         le16_to_cpu(dr->wLength));
 268                 goto exit;
 269         }
 270
 271         spin_lock(&desc->iuspin);
 272         responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
 273         if (!desc->resp_count++ && !responding
 274                 && !test_bit(WDM_DISCONNECTING, &desc->flags)
 275                 && !test_bit(WDM_SUSPENDING, &desc->flags)) {
 276                 rv = usb_submit_urb(desc->response, GFP_ATOMIC);
 277                 dev_dbg(&desc->intf->dev, "%s: usb_submit_urb %d",
 278                         __func__, rv);
 279         }
 280         spin_unlock(&desc->iuspin);
 281         if (rv < 0) {
 282                 clear_bit(WDM_RESPONDING, &desc->flags);
 283                 if (rv == -EPERM)
 284                         return;
 285                 if (rv == -ENOMEM) {
 286 sw:
 287                         rv = schedule_work(&desc->rxwork);
 288                         if (rv)
 289                                 dev_err(&desc->intf->dev,
 290                                         "Cannot schedule work\n");
 291                 }
 292         }
 293 exit:
 294         rv = usb_submit_urb(urb, GFP_ATOMIC);
 295         if (rv)
 296                 dev_err(&desc->intf->dev,
 297                         "%s - usb_submit_urb failed with result %d\n",
 298                         __func__, rv);
 299
 300 }
 301
 302 static void kill_urbs(struct wdm_device *desc)
 303 {
 304         /* the order here is essential */
 305         usb_kill_urb(desc->command);
 306         usb_kill_urb(desc->validity);
 307         usb_kill_urb(desc->response);
 308 }
 309
 310 static void free_urbs(struct wdm_device *desc)
 311 {
 312         usb_free_urb(desc->validity);
 313         usb_free_urb(desc->response);
 314         usb_free_urb(desc->command);
 315 }
 316
 317 static void cleanup(struct wdm_device *desc)
 318 {
 319         kfree(desc->sbuf);
 320         kfree(desc->inbuf);
 321         kfree(desc->orq);
 322         kfree(desc->irq);
 323         kfree(desc->ubuf);
 324         free_urbs(desc);
 325         kfree(desc);
 326 }
 327
 328 static ssize_t wdm_write
 329 (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 330 {
 331         u8 *buf;
 332         int rv = -EMSGSIZE, r, we;
 333         struct wdm_device *desc = file->private_data;
 334         struct usb_ctrlrequest *req;
 335
 336         if (count > desc->wMaxCommand)
 337                 count = desc->wMaxCommand;
 338
 339         spin_lock_irq(&desc->iuspin);
 340         we = desc->werr;
 341         desc->werr = 0;
 342         spin_unlock_irq(&desc->iuspin);
 343         if (we < 0)
 344                 return usb_translate_errors(we);
 345
 346         buf = kmalloc(count, GFP_KERNEL);
 347         if (!buf) {
 348                 rv = -ENOMEM;
 349                 goto outnl;
 350         }
 351
 352         r = copy_from_user(buf, buffer, count);
 353         if (r > 0) {
 354                 rv = -EFAULT;
 355                 goto out_free_mem;
 356         }
 357
 358         /* concurrent writes and disconnect */
 359         r = mutex_lock_interruptible(&desc->wlock);
 360         rv = -ERESTARTSYS;
 361         if (r)
 362                 goto out_free_mem;
 363
 364         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 365                 rv = -ENODEV;
 366                 goto out_free_mem_lock;
 367         }
 368
 369         r = usb_autopm_get_interface(desc->intf);
 370         if (r < 0) {
 371                 rv = usb_translate_errors(r);
 372                 goto out_free_mem_lock;
 373         }
 374
 375         if (!(file->f_flags & O_NONBLOCK))
 376                 r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
 377                                                                 &desc->flags));
 378         else
 379                 if (test_bit(WDM_IN_USE, &desc->flags))
 380                         r = -EAGAIN;
 381
 382         if (test_bit(WDM_RESETTING, &desc->flags))
 383                 r = -EIO;
 384
 385         if (r < 0) {
 386                 rv = r;
 387                 goto out_free_mem_pm;
 388         }
 389
 390         req = desc->orq;
 391         usb_fill_control_urb(
 392                 desc->command,
 393                 interface_to_usbdev(desc->intf),
 394                 /* using common endpoint 0 */
 395                 usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
 396                 (unsigned char *)req,
 397                 buf,
 398                 count,
 399                 wdm_out_callback,
 400                 desc
 401         );
 402
 403         req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
 404                              USB_RECIP_INTERFACE);
 405         req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
 406         req->wValue = 0;
 407         req->wIndex = desc->inum; /* already converted */
 408         req->wLength = cpu_to_le16(count);
 409         set_bit(WDM_IN_USE, &desc->flags);
 410         desc->outbuf = buf;
 411
 412         rv = usb_submit_urb(desc->command, GFP_KERNEL);
 413         if (rv < 0) {
 414                 desc->outbuf = NULL;
 415                 clear_bit(WDM_IN_USE, &desc->flags);
 416                 dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
 417                 rv = usb_translate_errors(rv);
 418                 goto out_free_mem_pm;
 419         } else {
 420                 dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d",
 421                         le16_to_cpu(req->wIndex));
 422         }
 423
 424         usb_autopm_put_interface(desc->intf);
 425         mutex_unlock(&desc->wlock);
 426 outnl:
 427         return rv < 0 ? rv : count;
 428
 429 out_free_mem_pm:
 430         usb_autopm_put_interface(desc->intf);
 431 out_free_mem_lock:
 432         mutex_unlock(&desc->wlock);
 433 out_free_mem:
 434         kfree(buf);
 435         return rv;
 436 }
 437
 438 /*
 439  * clear WDM_READ flag and possibly submit the read urb if resp_count
 440  * is non-zero.
 441  *
 442  * Called with desc->iuspin locked
 443  */
 444 static int clear_wdm_read_flag(struct wdm_device *desc)
 445 {
 446         int rv = 0;
 447
 448         clear_bit(WDM_READ, &desc->flags);
 449
 450         /* submit read urb only if the device is waiting for it */
 451         if (!desc->resp_count || !--desc->resp_count)
 452                 goto out;
 453
 454         set_bit(WDM_RESPONDING, &desc->flags);
 455         spin_unlock_irq(&desc->iuspin);
 456         rv = usb_submit_urb(desc->response, GFP_KERNEL);
 457         spin_lock_irq(&desc->iuspin);
 458         if (rv) {
 459                 dev_err(&desc->intf->dev,
 460                         "usb_submit_urb failed with result %d\n", rv);
 461
 462                 /* make sure the next notification trigger a submit */
 463                 clear_bit(WDM_RESPONDING, &desc->flags);
 464                 desc->resp_count = 0;
 465         }
 466 out:
 467         return rv;
 468 }
 469
 470 static ssize_t wdm_read
 471 (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 472 {
 473         int rv, cntr;
 474         int i = 0;
 475         struct wdm_device *desc = file->private_data;
 476
 477
 478         rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
 479         if (rv < 0)
 480                 return -ERESTARTSYS;
 481
 482         cntr = ACCESS_ONCE(desc->length);
 483         if (cntr == 0) {
 484                 desc->read = 0;
 485 retry:
 486                 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 487                         rv = -ENODEV;
 488                         goto err;
 489                 }
 490                 if (test_bit(WDM_OVERFLOW, &desc->flags)) {
 491                         clear_bit(WDM_OVERFLOW, &desc->flags);
 492                         rv = -ENOBUFS;
 493                         goto err;
 494                 }
 495                 i++;
 496                 if (file->f_flags & O_NONBLOCK) {
 497                         if (!test_bit(WDM_READ, &desc->flags)) {
 498                                 rv = cntr ? cntr : -EAGAIN;
 499                                 goto err;
 500                         }
 501                         rv = 0;
 502                 } else {
 503                         rv = wait_event_interruptible(desc->wait,
 504                                 test_bit(WDM_READ, &desc->flags));
 505                 }
 506
 507                 /* may have happened while we slept */
 508                 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 509                         rv = -ENODEV;
 510                         goto err;
 511                 }
 512                 if (test_bit(WDM_RESETTING, &desc->flags)) {
 513                         rv = -EIO;
 514                         goto err;
 515                 }
 516                 usb_mark_last_busy(interface_to_usbdev(desc->intf));
 517                 if (rv < 0) {
 518                         rv = -ERESTARTSYS;
 519                         goto err;
 520                 }
 521
 522                 spin_lock_irq(&desc->iuspin);
 523
 524                 if (desc->rerr) { /* read completed, error happened */
 525                         rv = usb_translate_errors(desc->rerr);
 526                         desc->rerr = 0;
 527                         spin_unlock_irq(&desc->iuspin);
 528                         goto err;
 529                 }
 530                 /*
 531                  * recheck whether we've lost the race
 532                  * against the completion handler
 533                  */
 534                 if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */
 535                         spin_unlock_irq(&desc->iuspin);
 536                         goto retry;
 537                 }
 538
 539                 if (!desc->reslength) { /* zero length read */
 540                         dev_dbg(&desc->intf->dev, "%s: zero length - clearing WDM_READ\n", __func__);
 541                         rv = clear_wdm_read_flag(desc);
 542                         spin_unlock_irq(&desc->iuspin);
 543                         if (rv < 0)
 544                                 goto err;
 545                         goto retry;
 546                 }
 547                 cntr = desc->length;
 548                 spin_unlock_irq(&desc->iuspin);
 549         }
 550
 551         if (cntr > count)
 552                 cntr = count;
 553         rv = copy_to_user(buffer, desc->ubuf, cntr);
 554         if (rv > 0) {
 555                 rv = -EFAULT;
 556                 goto err;
 557         }
 558
 559         spin_lock_irq(&desc->iuspin);
 560
 561         for (i = 0; i < desc->length - cntr; i++)
 562                 desc->ubuf[i] = desc->ubuf[i + cntr];
 563
 564         desc->length -= cntr;
 565         /* in case we had outstanding data */
 566         if (!desc->length)
 567                 clear_wdm_read_flag(desc);
 568         spin_unlock_irq(&desc->iuspin);
 569         rv = cntr;
 570
 571 err:
 572         mutex_unlock(&desc->rlock);
 573         return rv;
 574 }
 575
 576 static int wdm_flush(struct file *file, fl_owner_t id)
 577 {
 578         struct wdm_device *desc = file->private_data;
 579
 580         wait_event(desc->wait,
 581                         /*
 582                          * needs both flags. We cannot do with one
 583                          * because resetting it would cause a race
 584                          * with write() yet we need to signal
 585                          * a disconnect
 586                          */
 587                         !test_bit(WDM_IN_USE, &desc->flags) ||
 588                         test_bit(WDM_DISCONNECTING, &desc->flags));
 589
 590         /* cannot dereference desc->intf if WDM_DISCONNECTING */
 591         if (test_bit(WDM_DISCONNECTING, &desc->flags))
 592                 return -ENODEV;
 593         if (desc->werr < 0)
 594                 dev_err(&desc->intf->dev, "Error in flush path: %d\n",
 595                         desc->werr);
 596
 597         return usb_translate_errors(desc->werr);
 598 }
 599
 600 static unsigned int wdm_poll(struct file *file, struct poll_table_struct *wait)
 601 {
 602         struct wdm_device *desc = file->private_data;
 603         unsigned long flags;
 604         unsigned int mask = 0;
 605
 606         spin_lock_irqsave(&desc->iuspin, flags);
 607         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 608                 mask = POLLHUP | POLLERR;
 609                 spin_unlock_irqrestore(&desc->iuspin, flags);
 610                 goto desc_out;
 611         }
 612         if (test_bit(WDM_READ, &desc->flags))
 613                 mask = POLLIN | POLLRDNORM;
 614         if (desc->rerr || desc->werr)
 615                 mask |= POLLERR;
 616         if (!test_bit(WDM_IN_USE, &desc->flags))
 617                 mask |= POLLOUT | POLLWRNORM;
 618         spin_unlock_irqrestore(&desc->iuspin, flags);
 619
 620         poll_wait(file, &desc->wait, wait);
 621
 622 desc_out:
 623         return mask;
 624 }
 625
 626 static int wdm_open(struct inode *inode, struct file *file)
 627 {
 628         int minor = iminor(inode);
 629         int rv = -ENODEV;
 630         struct usb_interface *intf;
 631         struct wdm_device *desc;
 632
 633         mutex_lock(&wdm_mutex);
 634         desc = wdm_find_device_by_minor(minor);
 635         if (!desc)
 636                 goto out;
 637
 638         intf = desc->intf;
 639         if (test_bit(WDM_DISCONNECTING, &desc->flags))
 640                 goto out;
 641         file->private_data = desc;
 642
 643         rv = usb_autopm_get_interface(desc->intf);
 644         if (rv < 0) {
 645                 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
 646                 goto out;
 647         }
 648
 649         /* using write lock to protect desc->count */
 650         mutex_lock(&desc->wlock);
 651         if (!desc->count++) {
 652                 desc->werr = 0;
 653                 desc->rerr = 0;
 654                 rv = usb_submit_urb(desc->validity, GFP_KERNEL);
 655                 if (rv < 0) {
 656                         desc->count--;
 657                         dev_err(&desc->intf->dev,
 658                                 "Error submitting int urb - %d\n", rv);
 659                         rv = usb_translate_errors(rv);
 660                 }
 661         } else {
 662                 rv = 0;
 663         }
 664         mutex_unlock(&desc->wlock);
 665         if (desc->count == 1)
 666                 desc->manage_power(intf, 1);
 667         usb_autopm_put_interface(desc->intf);
 668 out:
 669         mutex_unlock(&wdm_mutex);
 670         return rv;
 671 }
 672
 673 static int wdm_release(struct inode *inode, struct file *file)
 674 {
 675         struct wdm_device *desc = file->private_data;
 676
 677         mutex_lock(&wdm_mutex);
 678
 679         /* using write lock to protect desc->count */
 680         mutex_lock(&desc->wlock);
 681         desc->count--;
 682         mutex_unlock(&desc->wlock);
 683
 684         if (!desc->count) {
 685                 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
 686                         dev_dbg(&desc->intf->dev, "wdm_release: cleanup");
 687                         kill_urbs(desc);
 688                         spin_lock_irq(&desc->iuspin);
 689                         desc->resp_count = 0;
 690                         spin_unlock_irq(&desc->iuspin);
 691                         desc->manage_power(desc->intf, 0);
 692                 } else {
 693                         /* must avoid dev_printk here as desc->intf is invalid */
 694                         pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
 695                         cleanup(desc);
 696                 }
 697         }
 698         mutex_unlock(&wdm_mutex);
 699         return 0;
 700 }
 701
 702 static long wdm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 703 {
 704         struct wdm_device *desc = file->private_data;
 705         int rv = 0;
 706
 707         switch (cmd) {
 708         case IOCTL_WDM_MAX_COMMAND:
 709                 if (copy_to_user((void __user *)arg, &desc->wMaxCommand, sizeof(desc->wMaxCommand)))
 710                         rv = -EFAULT;
 711                 break;
 712         default:
 713                 rv = -ENOTTY;
 714         }
 715         return rv;
 716 }
 717
 718 static const struct file_operations wdm_fops = {
 719         .owner =        THIS_MODULE,
 720         .read =         wdm_read,
 721         .write =        wdm_write,
 722         .open =         wdm_open,
 723         .flush =        wdm_flush,
 724         .release =      wdm_release,
 725         .poll =         wdm_poll,
 726         .unlocked_ioctl = wdm_ioctl,
 727         .compat_ioctl = wdm_ioctl,
 728         .llseek =       noop_llseek,
 729 };
 730
 731 static struct usb_class_driver wdm_class = {
 732         .name =         "cdc-wdm%d",
 733         .fops =         &wdm_fops,
 734         .minor_base =   WDM_MINOR_BASE,
 735 };
 736
 737 /* --- error handling --- */
 738 static void wdm_rxwork(struct work_struct *work)
 739 {
 740         struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
 741         unsigned long flags;
 742         int rv = 0;
 743         int responding;
 744
 745         spin_lock_irqsave(&desc->iuspin, flags);
 746         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 747                 spin_unlock_irqrestore(&desc->iuspin, flags);
 748         } else {
 749                 responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
 750                 spin_unlock_irqrestore(&desc->iuspin, flags);
 751                 if (!responding)
 752                         rv = usb_submit_urb(desc->response, GFP_KERNEL);
 753                 if (rv < 0 && rv != -EPERM) {
 754                         spin_lock_irqsave(&desc->iuspin, flags);
 755                         clear_bit(WDM_RESPONDING, &desc->flags);
 756                         if (!test_bit(WDM_DISCONNECTING, &desc->flags))
 757                                 schedule_work(&desc->rxwork);
 758                         spin_unlock_irqrestore(&desc->iuspin, flags);
 759                 }
 760         }
 761 }
 762
 763 /* --- hotplug --- */
 764
 765 static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
 766                 u16 bufsize, int (*manage_power)(struct usb_interface *, int))
 767 {
 768         int rv = -ENOMEM;
 769         struct wdm_device *desc;
 770
 771         desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
 772         if (!desc)
 773                 goto out;
 774         INIT_LIST_HEAD(&desc->device_list);
 775         mutex_init(&desc->rlock);
 776         mutex_init(&desc->wlock);
 777         spin_lock_init(&desc->iuspin);
 778         init_waitqueue_head(&desc->wait);
 779         desc->wMaxCommand = bufsize;
 780         /* this will be expanded and needed in hardware endianness */
 781         desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
 782         desc->intf = intf;
 783         INIT_WORK(&desc->rxwork, wdm_rxwork);
 784
 785         rv = -EINVAL;
 786         if (!usb_endpoint_is_int_in(ep))
 787                 goto err;
 788
 789         desc->wMaxPacketSize = usb_endpoint_maxp(ep);
 790
 791         desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
 792         if (!desc->orq)
 793                 goto err;
 794         desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
 795         if (!desc->irq)
 796                 goto err;
 797
 798         desc->validity = usb_alloc_urb(0, GFP_KERNEL);
 799         if (!desc->validity)
 800                 goto err;
 801
 802         desc->response = usb_alloc_urb(0, GFP_KERNEL);
 803         if (!desc->response)
 804                 goto err;
 805
 806         desc->command = usb_alloc_urb(0, GFP_KERNEL);
 807         if (!desc->command)
 808                 goto err;
 809
 810         desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
 811         if (!desc->ubuf)
 812                 goto err;
 813
 814         desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);
 815         if (!desc->sbuf)
 816                 goto err;
 817
 818         desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
 819         if (!desc->inbuf)
 820                 goto err;
 821
 822         usb_fill_int_urb(
 823                 desc->validity,
 824                 interface_to_usbdev(intf),
 825                 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
 826                 desc->sbuf,
 827                 desc->wMaxPacketSize,
 828                 wdm_int_callback,
 829                 desc,
 830                 ep->bInterval
 831         );
 832
 833         desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
 834         desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
 835         desc->irq->wValue = 0;
 836         desc->irq->wIndex = desc->inum; /* already converted */
 837         desc->irq->wLength = cpu_to_le16(desc->wMaxCommand);
 838
 839         usb_fill_control_urb(
 840                 desc->response,
 841                 interface_to_usbdev(intf),
 842                 /* using common endpoint 0 */
 843                 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
 844                 (unsigned char *)desc->irq,
 845                 desc->inbuf,
 846                 desc->wMaxCommand,
 847                 wdm_in_callback,
 848                 desc
 849         );
 850
 851         desc->manage_power = manage_power;
 852
 853         spin_lock(&wdm_device_list_lock);
 854         list_add(&desc->device_list, &wdm_device_list);
 855         spin_unlock(&wdm_device_list_lock);
 856
 857         rv = usb_register_dev(intf, &wdm_class);
 858         if (rv < 0)
 859                 goto err;
 860         else
 861                 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev));
 862 out:
 863         return rv;
 864 err:
 865         spin_lock(&wdm_device_list_lock);
 866         list_del(&desc->device_list);
 867         spin_unlock(&wdm_device_list_lock);
 868         cleanup(desc);
 869         return rv;
 870 }
 871
 872 static int wdm_manage_power(struct usb_interface *intf, int on)
 873 {
 874         /* need autopm_get/put here to ensure the usbcore sees the new value */
 875         int rv = usb_autopm_get_interface(intf);
 876
 877         intf->needs_remote_wakeup = on;
 878         if (!rv)
 879                 usb_autopm_put_interface(intf);
 880         return 0;
 881 }
 882
 883 static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
 884 {
 885         int rv = -EINVAL;
 886         struct usb_host_interface *iface;
 887         struct usb_endpoint_descriptor *ep;
 888         struct usb_cdc_dmm_desc *dmhd;
 889         u8 *buffer = intf->altsetting->extra;
 890         int buflen = intf->altsetting->extralen;
 891         u16 maxcom = WDM_DEFAULT_BUFSIZE;
 892
 893         if (!buffer)
 894                 goto err;
 895         while (buflen > 2) {
 896                 if (buffer[1] != USB_DT_CS_INTERFACE) {
 897                         dev_err(&intf->dev, "skipping garbage\n");
 898                         goto next_desc;
 899                 }
 900
 901                 switch (buffer[2]) {
 902                 case USB_CDC_HEADER_TYPE:
 903                         break;
 904                 case USB_CDC_DMM_TYPE:
 905                         dmhd = (struct usb_cdc_dmm_desc *)buffer;
 906                         maxcom = le16_to_cpu(dmhd->wMaxCommand);
 907                         dev_dbg(&intf->dev,
 908                                 "Finding maximum buffer length: %d", maxcom);
 909                         break;
 910                 default:
 911                         dev_err(&intf->dev,
 912                                 "Ignoring extra header, type %d, length %d\n",
 913                                 buffer[2], buffer[0]);
 914                         break;
 915                 }
 916 next_desc:
 917                 buflen -= buffer[0];
 918                 buffer += buffer[0];
 919         }
 920
 921         iface = intf->cur_altsetting;
 922         if (iface->desc.bNumEndpoints != 1)
 923                 goto err;
 924         ep = &iface->endpoint[0].desc;
 925
 926         rv = wdm_create(intf, ep, maxcom, &wdm_manage_power);
 927
 928 err:
 929         return rv;
 930 }
 931
 932 /**
 933  * usb_cdc_wdm_register - register a WDM subdriver
 934  * @intf: usb interface the subdriver will associate with
 935  * @ep: interrupt endpoint to monitor for notifications
 936  * @bufsize: maximum message size to support for read/write
 937  *
 938  * Create WDM usb class character device and associate it with intf
 939  * without binding, allowing another driver to manage the interface.
 940  *
 941  * The subdriver will manage the given interrupt endpoint exclusively
 942  * and will issue control requests referring to the given intf. It
 943  * will otherwise avoid interferring, and in particular not do
 944  * usb_set_intfdata/usb_get_intfdata on intf.
 945  *
 946  * The return value is a pointer to the subdriver's struct usb_driver.
 947  * The registering driver is responsible for calling this subdriver's
 948  * disconnect, suspend, resume, pre_reset and post_reset methods from
 949  * its own.
 950  */
 951 struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,
 952                                         struct usb_endpoint_descriptor *ep,
 953                                         int bufsize,
 954                                         int (*manage_power)(struct usb_interface *, int))
 955 {
 956         int rv = -EINVAL;
 957
 958         rv = wdm_create(intf, ep, bufsize, manage_power);
 959         if (rv < 0)
 960                 goto err;
 961
 962         return &wdm_driver;
 963 err:
 964         return ERR_PTR(rv);
 965 }
 966 EXPORT_SYMBOL(usb_cdc_wdm_register);
 967
 968 static void wdm_disconnect(struct usb_interface *intf)
 969 {
 970         struct wdm_device *desc;
 971         unsigned long flags;
 972
 973         usb_deregister_dev(intf, &wdm_class);
 974         desc = wdm_find_device(intf);
 975         mutex_lock(&wdm_mutex);
 976
 977         /* the spinlock makes sure no new urbs are generated in the callbacks */
 978         spin_lock_irqsave(&desc->iuspin, flags);
 979         set_bit(WDM_DISCONNECTING, &desc->flags);
 980         set_bit(WDM_READ, &desc->flags);
 981         spin_unlock_irqrestore(&desc->iuspin, flags);
 982         wake_up_all(&desc->wait);
 983         mutex_lock(&desc->rlock);
 984         mutex_lock(&desc->wlock);
 985         kill_urbs(desc);
 986         cancel_work_sync(&desc->rxwork);
 987         mutex_unlock(&desc->wlock);
 988         mutex_unlock(&desc->rlock);
 989
 990         /* the desc->intf pointer used as list key is now invalid */
 991         spin_lock(&wdm_device_list_lock);
 992         list_del(&desc->device_list);
 993         spin_unlock(&wdm_device_list_lock);
 994
 995         if (!desc->count)
 996                 cleanup(desc);
 997         else
 998                 dev_dbg(&intf->dev, "%s: %d open files - postponing cleanup\n", __func__, desc->count);
 999         mutex_unlock(&wdm_mutex);
1000 }
1001
1002 #ifdef CONFIG_PM
1003 static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
1004 {
1005         struct wdm_device *desc = wdm_find_device(intf);
1006         int rv = 0;
1007
1008         dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
1009
1010         /* if this is an autosuspend the caller does the locking */
1011         if (!PMSG_IS_AUTO(message)) {
1012                 mutex_lock(&desc->rlock);
1013                 mutex_lock(&desc->wlock);
1014         }
1015         spin_lock_irq(&desc->iuspin);
1016
1017         if (PMSG_IS_AUTO(message) &&
1018                         (test_bit(WDM_IN_USE, &desc->flags)
1019                         || test_bit(WDM_RESPONDING, &desc->flags))) {
1020                 spin_unlock_irq(&desc->iuspin);
1021                 rv = -EBUSY;
1022         } else {
1023
1024                 set_bit(WDM_SUSPENDING, &desc->flags);
1025                 spin_unlock_irq(&desc->iuspin);
1026                 /* callback submits work - order is essential */
1027                 kill_urbs(desc);
1028                 cancel_work_sync(&desc->rxwork);
1029         }
1030         if (!PMSG_IS_AUTO(message)) {
1031                 mutex_unlock(&desc->wlock);
1032                 mutex_unlock(&desc->rlock);
1033         }
1034
1035         return rv;
1036 }
1037 #endif
1038
1039 static int recover_from_urb_loss(struct wdm_device *desc)
1040 {
1041         int rv = 0;
1042
1043         if (desc->count) {
1044                 rv = usb_submit_urb(desc->validity, GFP_NOIO);
1045                 if (rv < 0)
1046                         dev_err(&desc->intf->dev,
1047                                 "Error resume submitting int urb - %d\n", rv);
1048         }
1049         return rv;
1050 }
1051
1052 #ifdef CONFIG_PM
1053 static int wdm_resume(struct usb_interface *intf)
1054 {
1055         struct wdm_device *desc = wdm_find_device(intf);
1056         int rv;
1057
1058         dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
1059
1060         clear_bit(WDM_SUSPENDING, &desc->flags);
1061         rv = recover_from_urb_loss(desc);
1062
1063         return rv;
1064 }
1065 #endif
1066
1067 static int wdm_pre_reset(struct usb_interface *intf)
1068 {
1069         struct wdm_device *desc = wdm_find_device(intf);
1070
1071         /*
1072          * we notify everybody using poll of
1073          * an exceptional situation
1074          * must be done before recovery lest a spontaneous
1075          * message from the device is lost
1076          */
1077         spin_lock_irq(&desc->iuspin);
1078         set_bit(WDM_RESETTING, &desc->flags);   /* inform read/write */
1079         set_bit(WDM_READ, &desc->flags);        /* unblock read */
1080         clear_bit(WDM_IN_USE, &desc->flags);    /* unblock write */
1081         desc->rerr = -EINTR;
1082         spin_unlock_irq(&desc->iuspin);
1083         wake_up_all(&desc->wait);
1084         mutex_lock(&desc->rlock);
1085         mutex_lock(&desc->wlock);
1086         kill_urbs(desc);
1087         cancel_work_sync(&desc->rxwork);
1088         return 0;
1089 }
1090
1091 static int wdm_post_reset(struct usb_interface *intf)
1092 {
1093         struct wdm_device *desc = wdm_find_device(intf);
1094         int rv;
1095
1096         clear_bit(WDM_OVERFLOW, &desc->flags);
1097         clear_bit(WDM_RESETTING, &desc->flags);
1098         rv = recover_from_urb_loss(desc);
1099         mutex_unlock(&desc->wlock);
1100         mutex_unlock(&desc->rlock);
1101         return 0;
1102 }
1103
1104 static struct usb_driver wdm_driver = {
1105         .name =         "cdc_wdm",
1106         .probe =        wdm_probe,
1107         .disconnect =   wdm_disconnect,
1108 #ifdef CONFIG_PM
1109         .suspend =      wdm_suspend,
1110         .resume =       wdm_resume,
1111         .reset_resume = wdm_resume,
1112 #endif
1113         .pre_reset =    wdm_pre_reset,
1114         .post_reset =   wdm_post_reset,
1115         .id_table =     wdm_ids,
1116         .supports_autosuspend = 1,
1117         .disable_hub_initiated_lpm = 1,
1118 };
1119
1120 module_usb_driver(wdm_driver);
1121
1122 MODULE_AUTHOR(DRIVER_AUTHOR);
1123 MODULE_DESCRIPTION(DRIVER_DESC);
1124 MODULE_LICENSE("GPL");