drivers/usb/class/cdc-wdm.c

   1 /*
   2  * cdc-wdm.c
   3  *
   4  * This driver supports USB CDC WCM Device Management.
   5  *
   6  * Copyright (c) 2007-2009 Oliver Neukum
   7  *
   8  * Some code taken from cdc-acm.c
   9  *
  10  * Released under the GPLv2.
  11  *
  12  * Many thanks to Carl Nordbeck
  13  */
  14 #include <linux/kernel.h>
  15 #include <linux/errno.h>
  16 #include <linux/slab.h>
  17 #include <linux/module.h>
  18 #include <linux/mutex.h>
  19 #include <linux/uaccess.h>
  20 #include <linux/bitops.h>
  21 #include <linux/poll.h>
  22 #include <linux/usb.h>
  23 #include <linux/usb/cdc.h>
  24 #include <asm/byteorder.h>
  25 #include <asm/unaligned.h>
  26
  27 /*
  28  * Version Information
  29  */
  30 #define DRIVER_VERSION "v0.03"
  31 #define DRIVER_AUTHOR "Oliver Neukum"
  32 #define DRIVER_DESC "USB Abstract Control Model driver for USB WCM Device Management"
  33
  34 static const struct usb_device_id wdm_ids[] = {
  35         {
  36                 .match_flags = USB_DEVICE_ID_MATCH_INT_CLASS |
  37                                  USB_DEVICE_ID_MATCH_INT_SUBCLASS,
  38                 .bInterfaceClass = USB_CLASS_COMM,
  39                 .bInterfaceSubClass = USB_CDC_SUBCLASS_DMM
  40         },
  41         { }
  42 };
  43
  44 MODULE_DEVICE_TABLE (usb, wdm_ids);
  45
  46 #define WDM_MINOR_BASE  176
  47
  48
  49 #define WDM_IN_USE              1
  50 #define WDM_DISCONNECTING       2
  51 #define WDM_RESULT              3
  52 #define WDM_READ                4
  53 #define WDM_INT_STALL           5
  54 #define WDM_POLL_RUNNING        6
  55 #define WDM_RESPONDING          7
  56 #define WDM_SUSPENDING          8
  57
  58 #define WDM_MAX                 16
  59
  60 /* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */
  61 #define WDM_DEFAULT_BUFSIZE     256
  62
  63 static DEFINE_MUTEX(wdm_mutex);
  64
  65 /* --- method tables --- */
  66
  67 struct wdm_device {
  68         u8                      *inbuf; /* buffer for response */
  69         u8                      *outbuf; /* buffer for command */
  70         u8                      *sbuf; /* buffer for status */
  71         u8                      *ubuf; /* buffer for copy to user space */
  72
  73         struct urb              *command;
  74         struct urb              *response;
  75         struct urb              *validity;
  76         struct usb_interface    *intf;
  77         struct usb_ctrlrequest  *orq;
  78         struct usb_ctrlrequest  *irq;
  79         spinlock_t              iuspin;
  80
  81         unsigned long           flags;
  82         u16                     bufsize;
  83         u16                     wMaxCommand;
  84         u16                     wMaxPacketSize;
  85         u16                     bMaxPacketSize0;
  86         __le16                  inum;
  87         int                     reslength;
  88         int                     length;
  89         int                     read;
  90         int                     count;
  91         dma_addr_t              shandle;
  92         dma_addr_t              ihandle;
  93         struct mutex            wlock;
  94         struct mutex            rlock;
  95         wait_queue_head_t       wait;
  96         struct work_struct      rxwork;
  97         int                     werr;
  98         int                     rerr;
  99 };
 100
 101 static struct usb_driver wdm_driver;
 102
 103 /* --- callbacks --- */
 104 static void wdm_out_callback(struct urb *urb)
 105 {
 106         struct wdm_device *desc;
 107         desc = urb->context;
 108         spin_lock(&desc->iuspin);
 109         desc->werr = urb->status;
 110         spin_unlock(&desc->iuspin);
 111         clear_bit(WDM_IN_USE, &desc->flags);
 112         kfree(desc->outbuf);
 113         wake_up(&desc->wait);
 114 }
 115
 116 static void wdm_in_callback(struct urb *urb)
 117 {
 118         struct wdm_device *desc = urb->context;
 119         int status = urb->status;
 120
 121         spin_lock(&desc->iuspin);
 122         clear_bit(WDM_RESPONDING, &desc->flags);
 123
 124         if (status) {
 125                 switch (status) {
 126                 case -ENOENT:
 127                         dev_dbg(&desc->intf->dev,
 128                                 "nonzero urb status received: -ENOENT");
 129                         goto skip_error;
 130                 case -ECONNRESET:
 131                         dev_dbg(&desc->intf->dev,
 132                                 "nonzero urb status received: -ECONNRESET");
 133                         goto skip_error;
 134                 case -ESHUTDOWN:
 135                         dev_dbg(&desc->intf->dev,
 136                                 "nonzero urb status received: -ESHUTDOWN");
 137                         goto skip_error;
 138                 case -EPIPE:
 139                         dev_err(&desc->intf->dev,
 140                                 "nonzero urb status received: -EPIPE\n");
 141                         break;
 142                 default:
 143                         dev_err(&desc->intf->dev,
 144                                 "Unexpected error %d\n", status);
 145                         break;
 146                 }
 147         }
 148
 149         desc->rerr = status;
 150         desc->reslength = urb->actual_length;
 151         memmove(desc->ubuf + desc->length, desc->inbuf, desc->reslength);
 152         desc->length += desc->reslength;
 153 skip_error:
 154         wake_up(&desc->wait);
 155
 156         set_bit(WDM_READ, &desc->flags);
 157         spin_unlock(&desc->iuspin);
 158 }
 159
 160 static void wdm_int_callback(struct urb *urb)
 161 {
 162         int rv = 0;
 163         int status = urb->status;
 164         struct wdm_device *desc;
 165         struct usb_ctrlrequest *req;
 166         struct usb_cdc_notification *dr;
 167
 168         desc = urb->context;
 169         req = desc->irq;
 170         dr = (struct usb_cdc_notification *)desc->sbuf;
 171
 172         if (status) {
 173                 switch (status) {
 174                 case -ESHUTDOWN:
 175                 case -ENOENT:
 176                 case -ECONNRESET:
 177                         return; /* unplug */
 178                 case -EPIPE:
 179                         set_bit(WDM_INT_STALL, &desc->flags);
 180                         dev_err(&desc->intf->dev, "Stall on int endpoint\n");
 181                         goto sw; /* halt is cleared in work */
 182                 default:
 183                         dev_err(&desc->intf->dev,
 184                                 "nonzero urb status received: %d\n", status);
 185                         break;
 186                 }
 187         }
 188
 189         if (urb->actual_length < sizeof(struct usb_cdc_notification)) {
 190                 dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n",
 191                         urb->actual_length);
 192                 goto exit;
 193         }
 194
 195         switch (dr->bNotificationType) {
 196         case USB_CDC_NOTIFY_RESPONSE_AVAILABLE:
 197                 dev_dbg(&desc->intf->dev,
 198                         "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d",
 199                         dr->wIndex, dr->wLength);
 200                 break;
 201
 202         case USB_CDC_NOTIFY_NETWORK_CONNECTION:
 203
 204                 dev_dbg(&desc->intf->dev,
 205                         "NOTIFY_NETWORK_CONNECTION %s network",
 206                         dr->wValue ? "connected to" : "disconnected from");
 207                 goto exit;
 208         default:
 209                 clear_bit(WDM_POLL_RUNNING, &desc->flags);
 210                 dev_err(&desc->intf->dev,
 211                         "unknown notification %d received: index %d len %d\n",
 212                         dr->bNotificationType, dr->wIndex, dr->wLength);
 213                 goto exit;
 214         }
 215
 216         req->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
 217         req->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
 218         req->wValue = 0;
 219         req->wIndex = desc->inum;
 220         req->wLength = cpu_to_le16(desc->wMaxCommand);
 221
 222         usb_fill_control_urb(
 223                 desc->response,
 224                 interface_to_usbdev(desc->intf),
 225                 /* using common endpoint 0 */
 226                 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
 227                 (unsigned char *)req,
 228                 desc->inbuf,
 229                 desc->wMaxCommand,
 230                 wdm_in_callback,
 231                 desc
 232         );
 233         desc->response->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 234         spin_lock(&desc->iuspin);
 235         clear_bit(WDM_READ, &desc->flags);
 236         set_bit(WDM_RESPONDING, &desc->flags);
 237         if (!test_bit(WDM_DISCONNECTING, &desc->flags)
 238                 && !test_bit(WDM_SUSPENDING, &desc->flags)) {
 239                 rv = usb_submit_urb(desc->response, GFP_ATOMIC);
 240                 dev_dbg(&desc->intf->dev, "%s: usb_submit_urb %d",
 241                         __func__, rv);
 242         }
 243         spin_unlock(&desc->iuspin);
 244         if (rv < 0) {
 245                 clear_bit(WDM_RESPONDING, &desc->flags);
 246                 if (rv == -EPERM)
 247                         return;
 248                 if (rv == -ENOMEM) {
 249 sw:
 250                         rv = schedule_work(&desc->rxwork);
 251                         if (rv)
 252                                 dev_err(&desc->intf->dev,
 253                                         "Cannot schedule work\n");
 254                 }
 255         }
 256 exit:
 257         rv = usb_submit_urb(urb, GFP_ATOMIC);
 258         if (rv)
 259                 dev_err(&desc->intf->dev,
 260                         "%s - usb_submit_urb failed with result %d\n",
 261                         __func__, rv);
 262
 263 }
 264
 265 static void kill_urbs(struct wdm_device *desc)
 266 {
 267         /* the order here is essential */
 268         usb_kill_urb(desc->command);
 269         usb_kill_urb(desc->validity);
 270         usb_kill_urb(desc->response);
 271 }
 272
 273 static void free_urbs(struct wdm_device *desc)
 274 {
 275         usb_free_urb(desc->validity);
 276         usb_free_urb(desc->response);
 277         usb_free_urb(desc->command);
 278 }
 279
 280 static void cleanup(struct wdm_device *desc)
 281 {
 282         usb_free_coherent(interface_to_usbdev(desc->intf),
 283                           desc->wMaxPacketSize,
 284                           desc->sbuf,
 285                           desc->validity->transfer_dma);
 286         usb_free_coherent(interface_to_usbdev(desc->intf),
 287                           desc->bMaxPacketSize0,
 288                           desc->inbuf,
 289                           desc->response->transfer_dma);
 290         kfree(desc->orq);
 291         kfree(desc->irq);
 292         kfree(desc->ubuf);
 293         free_urbs(desc);
 294         kfree(desc);
 295 }
 296
 297 static ssize_t wdm_write
 298 (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 299 {
 300         u8 *buf;
 301         int rv = -EMSGSIZE, r, we;
 302         struct wdm_device *desc = file->private_data;
 303         struct usb_ctrlrequest *req;
 304
 305         if (count > desc->wMaxCommand)
 306                 count = desc->wMaxCommand;
 307
 308         spin_lock_irq(&desc->iuspin);
 309         we = desc->werr;
 310         desc->werr = 0;
 311         spin_unlock_irq(&desc->iuspin);
 312         if (we < 0)
 313                 return -EIO;
 314
 315         desc->outbuf = buf = kmalloc(count, GFP_KERNEL);
 316         if (!buf) {
 317                 rv = -ENOMEM;
 318                 goto outnl;
 319         }
 320
 321         r = copy_from_user(buf, buffer, count);
 322         if (r > 0) {
 323                 kfree(buf);
 324                 rv = -EFAULT;
 325                 goto outnl;
 326         }
 327
 328         /* concurrent writes and disconnect */
 329         r = mutex_lock_interruptible(&desc->wlock);
 330         rv = -ERESTARTSYS;
 331         if (r) {
 332                 kfree(buf);
 333                 goto outnl;
 334         }
 335
 336         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 337                 kfree(buf);
 338                 rv = -ENODEV;
 339                 goto outnp;
 340         }
 341
 342         r = usb_autopm_get_interface(desc->intf);
 343         if (r < 0) {
 344                 kfree(buf);
 345                 goto outnp;
 346         }
 347
 348         if (!(file->f_flags & O_NONBLOCK))
 349                 r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
 350                                                                 &desc->flags));
 351         else
 352                 if (test_bit(WDM_IN_USE, &desc->flags))
 353                         r = -EAGAIN;
 354         if (r < 0) {
 355                 kfree(buf);
 356                 goto out;
 357         }
 358
 359         req = desc->orq;
 360         usb_fill_control_urb(
 361                 desc->command,
 362                 interface_to_usbdev(desc->intf),
 363                 /* using common endpoint 0 */
 364                 usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
 365                 (unsigned char *)req,
 366                 buf,
 367                 count,
 368                 wdm_out_callback,
 369                 desc
 370         );
 371
 372         req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
 373                              USB_RECIP_INTERFACE);
 374         req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
 375         req->wValue = 0;
 376         req->wIndex = desc->inum;
 377         req->wLength = cpu_to_le16(count);
 378         set_bit(WDM_IN_USE, &desc->flags);
 379
 380         rv = usb_submit_urb(desc->command, GFP_KERNEL);
 381         if (rv < 0) {
 382                 kfree(buf);
 383                 clear_bit(WDM_IN_USE, &desc->flags);
 384                 dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
 385         } else {
 386                 dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d",
 387                         req->wIndex);
 388         }
 389 out:
 390         usb_autopm_put_interface(desc->intf);
 391 outnp:
 392         mutex_unlock(&desc->wlock);
 393 outnl:
 394         return rv < 0 ? rv : count;
 395 }
 396
 397 static ssize_t wdm_read
 398 (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 399 {
 400         int rv, cntr;
 401         int i = 0;
 402         struct wdm_device *desc = file->private_data;
 403
 404
 405         rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
 406         if (rv < 0)
 407                 return -ERESTARTSYS;
 408
 409         cntr = ACCESS_ONCE(desc->length);
 410         if (cntr == 0) {
 411                 desc->read = 0;
 412 retry:
 413                 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 414                         rv = -ENODEV;
 415                         goto err;
 416                 }
 417                 i++;
 418                 if (file->f_flags & O_NONBLOCK) {
 419                         if (!test_bit(WDM_READ, &desc->flags)) {
 420                                 rv = cntr ? cntr : -EAGAIN;
 421                                 goto err;
 422                         }
 423                         rv = 0;
 424                 } else {
 425                         rv = wait_event_interruptible(desc->wait,
 426                                 test_bit(WDM_READ, &desc->flags));
 427                 }
 428
 429                 /* may have happened while we slept */
 430                 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 431                         rv = -ENODEV;
 432                         goto err;
 433                 }
 434                 usb_mark_last_busy(interface_to_usbdev(desc->intf));
 435                 if (rv < 0) {
 436                         rv = -ERESTARTSYS;
 437                         goto err;
 438                 }
 439
 440                 spin_lock_irq(&desc->iuspin);
 441
 442                 if (desc->rerr) { /* read completed, error happened */
 443                         desc->rerr = 0;
 444                         spin_unlock_irq(&desc->iuspin);
 445                         rv = -EIO;
 446                         goto err;
 447                 }
 448                 /*
 449                  * recheck whether we've lost the race
 450                  * against the completion handler
 451                  */
 452                 if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */
 453                         spin_unlock_irq(&desc->iuspin);
 454                         goto retry;
 455                 }
 456                 if (!desc->reslength) { /* zero length read */
 457                         spin_unlock_irq(&desc->iuspin);
 458                         goto retry;
 459                 }
 460                 cntr = desc->length;
 461                 spin_unlock_irq(&desc->iuspin);
 462         }
 463
 464         if (cntr > count)
 465                 cntr = count;
 466         rv = copy_to_user(buffer, desc->ubuf, cntr);
 467         if (rv > 0) {
 468                 rv = -EFAULT;
 469                 goto err;
 470         }
 471
 472         spin_lock_irq(&desc->iuspin);
 473
 474         for (i = 0; i < desc->length - cntr; i++)
 475                 desc->ubuf[i] = desc->ubuf[i + cntr];
 476
 477         desc->length -= cntr;
 478         /* in case we had outstanding data */
 479         if (!desc->length)
 480                 clear_bit(WDM_READ, &desc->flags);
 481
 482         spin_unlock_irq(&desc->iuspin);
 483
 484         rv = cntr;
 485
 486 err:
 487         mutex_unlock(&desc->rlock);
 488         return rv;
 489 }
 490
 491 static int wdm_flush(struct file *file, fl_owner_t id)
 492 {
 493         struct wdm_device *desc = file->private_data;
 494
 495         wait_event(desc->wait, !test_bit(WDM_IN_USE, &desc->flags));
 496         if (desc->werr < 0)
 497                 dev_err(&desc->intf->dev, "Error in flush path: %d\n",
 498                         desc->werr);
 499
 500         return desc->werr;
 501 }
 502
 503 static unsigned int wdm_poll(struct file *file, struct poll_table_struct *wait)
 504 {
 505         struct wdm_device *desc = file->private_data;
 506         unsigned long flags;
 507         unsigned int mask = 0;
 508
 509         spin_lock_irqsave(&desc->iuspin, flags);
 510         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 511                 mask = POLLERR;
 512                 spin_unlock_irqrestore(&desc->iuspin, flags);
 513                 goto desc_out;
 514         }
 515         if (test_bit(WDM_READ, &desc->flags))
 516                 mask = POLLIN | POLLRDNORM;
 517         if (desc->rerr || desc->werr)
 518                 mask |= POLLERR;
 519         if (!test_bit(WDM_IN_USE, &desc->flags))
 520                 mask |= POLLOUT | POLLWRNORM;
 521         spin_unlock_irqrestore(&desc->iuspin, flags);
 522
 523         poll_wait(file, &desc->wait, wait);
 524
 525 desc_out:
 526         return mask;
 527 }
 528
 529 static int wdm_open(struct inode *inode, struct file *file)
 530 {
 531         int minor = iminor(inode);
 532         int rv = -ENODEV;
 533         struct usb_interface *intf;
 534         struct wdm_device *desc;
 535
 536         mutex_lock(&wdm_mutex);
 537         intf = usb_find_interface(&wdm_driver, minor);
 538         if (!intf)
 539                 goto out;
 540
 541         desc = usb_get_intfdata(intf);
 542         if (test_bit(WDM_DISCONNECTING, &desc->flags))
 543                 goto out;
 544         file->private_data = desc;
 545
 546         rv = usb_autopm_get_interface(desc->intf);
 547         if (rv < 0) {
 548                 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
 549                 goto out;
 550         }
 551         intf->needs_remote_wakeup = 1;
 552
 553         /* using write lock to protect desc->count */
 554         mutex_lock(&desc->wlock);
 555         if (!desc->count++) {
 556                 desc->werr = 0;
 557                 desc->rerr = 0;
 558                 rv = usb_submit_urb(desc->validity, GFP_KERNEL);
 559                 if (rv < 0) {
 560                         desc->count--;
 561                         dev_err(&desc->intf->dev,
 562                                 "Error submitting int urb - %d\n", rv);
 563                 }
 564         } else {
 565                 rv = 0;
 566         }
 567         mutex_unlock(&desc->wlock);
 568         usb_autopm_put_interface(desc->intf);
 569 out:
 570         mutex_unlock(&wdm_mutex);
 571         return rv;
 572 }
 573
 574 static int wdm_release(struct inode *inode, struct file *file)
 575 {
 576         struct wdm_device *desc = file->private_data;
 577
 578         mutex_lock(&wdm_mutex);
 579
 580         /* using write lock to protect desc->count */
 581         mutex_lock(&desc->wlock);
 582         desc->count--;
 583         mutex_unlock(&desc->wlock);
 584
 585         if (!desc->count) {
 586                 dev_dbg(&desc->intf->dev, "wdm_release: cleanup");
 587                 kill_urbs(desc);
 588                 if (!test_bit(WDM_DISCONNECTING, &desc->flags))
 589                         desc->intf->needs_remote_wakeup = 0;
 590         }
 591         mutex_unlock(&wdm_mutex);
 592         return 0;
 593 }
 594
 595 static const struct file_operations wdm_fops = {
 596         .owner =        THIS_MODULE,
 597         .read =         wdm_read,
 598         .write =        wdm_write,
 599         .open =         wdm_open,
 600         .flush =        wdm_flush,
 601         .release =      wdm_release,
 602         .poll =         wdm_poll,
 603         .llseek =       noop_llseek,
 604 };
 605
 606 static struct usb_class_driver wdm_class = {
 607         .name =         "cdc-wdm%d",
 608         .fops =         &wdm_fops,
 609         .minor_base =   WDM_MINOR_BASE,
 610 };
 611
 612 /* --- error handling --- */
 613 static void wdm_rxwork(struct work_struct *work)
 614 {
 615         struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
 616         unsigned long flags;
 617         int rv;
 618
 619         spin_lock_irqsave(&desc->iuspin, flags);
 620         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 621                 spin_unlock_irqrestore(&desc->iuspin, flags);
 622         } else {
 623                 spin_unlock_irqrestore(&desc->iuspin, flags);
 624                 rv = usb_submit_urb(desc->response, GFP_KERNEL);
 625                 if (rv < 0 && rv != -EPERM) {
 626                         spin_lock_irqsave(&desc->iuspin, flags);
 627                         if (!test_bit(WDM_DISCONNECTING, &desc->flags))
 628                                 schedule_work(&desc->rxwork);
 629                         spin_unlock_irqrestore(&desc->iuspin, flags);
 630                 }
 631         }
 632 }
 633
 634 /* --- hotplug --- */
 635
 636 static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
 637 {
 638         int rv = -EINVAL;
 639         struct usb_device *udev = interface_to_usbdev(intf);
 640         struct wdm_device *desc;
 641         struct usb_host_interface *iface;
 642         struct usb_endpoint_descriptor *ep;
 643         struct usb_cdc_dmm_desc *dmhd;
 644         u8 *buffer = intf->altsetting->extra;
 645         int buflen = intf->altsetting->extralen;
 646         u16 maxcom = WDM_DEFAULT_BUFSIZE;
 647
 648         if (!buffer)
 649                 goto out;
 650
 651         while (buflen > 2) {
 652                 if (buffer [1] != USB_DT_CS_INTERFACE) {
 653                         dev_err(&intf->dev, "skipping garbage\n");
 654                         goto next_desc;
 655                 }
 656
 657                 switch (buffer [2]) {
 658                 case USB_CDC_HEADER_TYPE:
 659                         break;
 660                 case USB_CDC_DMM_TYPE:
 661                         dmhd = (struct usb_cdc_dmm_desc *)buffer;
 662                         maxcom = le16_to_cpu(dmhd->wMaxCommand);
 663                         dev_dbg(&intf->dev,
 664                                 "Finding maximum buffer length: %d", maxcom);
 665                         break;
 666                 default:
 667                         dev_err(&intf->dev,
 668                                 "Ignoring extra header, type %d, length %d\n",
 669                                 buffer[2], buffer[0]);
 670                         break;
 671                 }
 672 next_desc:
 673                 buflen -= buffer[0];
 674                 buffer += buffer[0];
 675         }
 676
 677         rv = -ENOMEM;
 678         desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
 679         if (!desc)
 680                 goto out;
 681         mutex_init(&desc->rlock);
 682         mutex_init(&desc->wlock);
 683         spin_lock_init(&desc->iuspin);
 684         init_waitqueue_head(&desc->wait);
 685         desc->wMaxCommand = maxcom;
 686         /* this will be expanded and needed in hardware endianness */
 687         desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
 688         desc->intf = intf;
 689         INIT_WORK(&desc->rxwork, wdm_rxwork);
 690
 691         rv = -EINVAL;
 692         iface = intf->cur_altsetting;
 693         if (iface->desc.bNumEndpoints != 1)
 694                 goto err;
 695         ep = &iface->endpoint[0].desc;
 696         if (!ep || !usb_endpoint_is_int_in(ep))
 697                 goto err;
 698
 699         desc->wMaxPacketSize = usb_endpoint_maxp(ep);
 700         desc->bMaxPacketSize0 = udev->descriptor.bMaxPacketSize0;
 701
 702         desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
 703         if (!desc->orq)
 704                 goto err;
 705         desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
 706         if (!desc->irq)
 707                 goto err;
 708
 709         desc->validity = usb_alloc_urb(0, GFP_KERNEL);
 710         if (!desc->validity)
 711                 goto err;
 712
 713         desc->response = usb_alloc_urb(0, GFP_KERNEL);
 714         if (!desc->response)
 715                 goto err;
 716
 717         desc->command = usb_alloc_urb(0, GFP_KERNEL);
 718         if (!desc->command)
 719                 goto err;
 720
 721         desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
 722         if (!desc->ubuf)
 723                 goto err;
 724
 725         desc->sbuf = usb_alloc_coherent(interface_to_usbdev(intf),
 726                                         desc->wMaxPacketSize,
 727                                         GFP_KERNEL,
 728                                         &desc->validity->transfer_dma);
 729         if (!desc->sbuf)
 730                 goto err;
 731
 732         desc->inbuf = usb_alloc_coherent(interface_to_usbdev(intf),
 733                                          desc->wMaxCommand,
 734                                          GFP_KERNEL,
 735                                          &desc->response->transfer_dma);
 736         if (!desc->inbuf)
 737                 goto err2;
 738
 739         usb_fill_int_urb(
 740                 desc->validity,
 741                 interface_to_usbdev(intf),
 742                 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
 743                 desc->sbuf,
 744                 desc->wMaxPacketSize,
 745                 wdm_int_callback,
 746                 desc,
 747                 ep->bInterval
 748         );
 749         desc->validity->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 750
 751         usb_set_intfdata(intf, desc);
 752         rv = usb_register_dev(intf, &wdm_class);
 753         if (rv < 0)
 754                 goto err3;
 755         else
 756                 dev_info(&intf->dev, "cdc-wdm%d: USB WDM device\n",
 757                         intf->minor - WDM_MINOR_BASE);
 758 out:
 759         return rv;
 760 err3:
 761         usb_set_intfdata(intf, NULL);
 762         usb_free_coherent(interface_to_usbdev(desc->intf),
 763                           desc->bMaxPacketSize0,
 764                         desc->inbuf,
 765                         desc->response->transfer_dma);
 766 err2:
 767         usb_free_coherent(interface_to_usbdev(desc->intf),
 768                           desc->wMaxPacketSize,
 769                           desc->sbuf,
 770                           desc->validity->transfer_dma);
 771 err:
 772         free_urbs(desc);
 773         kfree(desc->ubuf);
 774         kfree(desc->orq);
 775         kfree(desc->irq);
 776         kfree(desc);
 777         return rv;
 778 }
 779
 780 static void wdm_disconnect(struct usb_interface *intf)
 781 {
 782         struct wdm_device *desc;
 783         unsigned long flags;
 784
 785         usb_deregister_dev(intf, &wdm_class);
 786         mutex_lock(&wdm_mutex);
 787         desc = usb_get_intfdata(intf);
 788
 789         /* the spinlock makes sure no new urbs are generated in the callbacks */
 790         spin_lock_irqsave(&desc->iuspin, flags);
 791         set_bit(WDM_DISCONNECTING, &desc->flags);
 792         set_bit(WDM_READ, &desc->flags);
 793         /* to terminate pending flushes */
 794         clear_bit(WDM_IN_USE, &desc->flags);
 795         spin_unlock_irqrestore(&desc->iuspin, flags);
 796         wake_up_all(&desc->wait);
 797         mutex_lock(&desc->rlock);
 798         mutex_lock(&desc->wlock);
 799         kill_urbs(desc);
 800         cancel_work_sync(&desc->rxwork);
 801         mutex_unlock(&desc->wlock);
 802         mutex_unlock(&desc->rlock);
 803         if (!desc->count)
 804                 cleanup(desc);
 805         mutex_unlock(&wdm_mutex);
 806 }
 807
 808 #ifdef CONFIG_PM
 809 static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
 810 {
 811         struct wdm_device *desc = usb_get_intfdata(intf);
 812         int rv = 0;
 813
 814         dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
 815
 816         /* if this is an autosuspend the caller does the locking */
 817         if (!PMSG_IS_AUTO(message)) {
 818                 mutex_lock(&desc->rlock);
 819                 mutex_lock(&desc->wlock);
 820         }
 821         spin_lock_irq(&desc->iuspin);
 822
 823         if (PMSG_IS_AUTO(message) &&
 824                         (test_bit(WDM_IN_USE, &desc->flags)
 825                         || test_bit(WDM_RESPONDING, &desc->flags))) {
 826                 spin_unlock_irq(&desc->iuspin);
 827                 rv = -EBUSY;
 828         } else {
 829
 830                 set_bit(WDM_SUSPENDING, &desc->flags);
 831                 spin_unlock_irq(&desc->iuspin);
 832                 /* callback submits work - order is essential */
 833                 kill_urbs(desc);
 834                 cancel_work_sync(&desc->rxwork);
 835         }
 836         if (!PMSG_IS_AUTO(message)) {
 837                 mutex_unlock(&desc->wlock);
 838                 mutex_unlock(&desc->rlock);
 839         }
 840
 841         return rv;
 842 }
 843 #endif
 844
 845 static int recover_from_urb_loss(struct wdm_device *desc)
 846 {
 847         int rv = 0;
 848
 849         if (desc->count) {
 850                 rv = usb_submit_urb(desc->validity, GFP_NOIO);
 851                 if (rv < 0)
 852                         dev_err(&desc->intf->dev,
 853                                 "Error resume submitting int urb - %d\n", rv);
 854         }
 855         return rv;
 856 }
 857
 858 #ifdef CONFIG_PM
 859 static int wdm_resume(struct usb_interface *intf)
 860 {
 861         struct wdm_device *desc = usb_get_intfdata(intf);
 862         int rv;
 863
 864         dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
 865
 866         clear_bit(WDM_SUSPENDING, &desc->flags);
 867         rv = recover_from_urb_loss(desc);
 868
 869         return rv;
 870 }
 871 #endif
 872
 873 static int wdm_pre_reset(struct usb_interface *intf)
 874 {
 875         struct wdm_device *desc = usb_get_intfdata(intf);
 876
 877         mutex_lock(&desc->rlock);
 878         mutex_lock(&desc->wlock);
 879         kill_urbs(desc);
 880
 881         /*
 882          * we notify everybody using poll of
 883          * an exceptional situation
 884          * must be done before recovery lest a spontaneous
 885          * message from the device is lost
 886          */
 887         spin_lock_irq(&desc->iuspin);
 888         desc->rerr = -EINTR;
 889         spin_unlock_irq(&desc->iuspin);
 890         wake_up_all(&desc->wait);
 891         return 0;
 892 }
 893
 894 static int wdm_post_reset(struct usb_interface *intf)
 895 {
 896         struct wdm_device *desc = usb_get_intfdata(intf);
 897         int rv;
 898
 899         rv = recover_from_urb_loss(desc);
 900         mutex_unlock(&desc->wlock);
 901         mutex_unlock(&desc->rlock);
 902         return 0;
 903 }
 904
 905 static struct usb_driver wdm_driver = {
 906         .name =         "cdc_wdm",
 907         .probe =        wdm_probe,
 908         .disconnect =   wdm_disconnect,
 909 #ifdef CONFIG_PM
 910         .suspend =      wdm_suspend,
 911         .resume =       wdm_resume,
 912         .reset_resume = wdm_resume,
 913 #endif
 914         .pre_reset =    wdm_pre_reset,
 915         .post_reset =   wdm_post_reset,
 916         .id_table =     wdm_ids,
 917         .supports_autosuspend = 1,
 918 };
 919
 920 /* --- low level module stuff --- */
 921
 922 static int __init wdm_init(void)
 923 {
 924         int rv;
 925
 926         rv = usb_register(&wdm_driver);
 927
 928         return rv;
 929 }
 930
 931 static void __exit wdm_exit(void)
 932 {
 933         usb_deregister(&wdm_driver);
 934 }
 935
 936 module_init(wdm_init);
 937 module_exit(wdm_exit);
 938
 939 MODULE_AUTHOR(DRIVER_AUTHOR);
 940 MODULE_DESCRIPTION(DRIVER_DESC);
 941 MODULE_LICENSE("GPL");