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 #define HUAWEI_VENDOR_ID        0x12D1
  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                  * Huawei E392, E398 and possibly other Qualcomm based modems
  46                  * embed the Qualcomm QMI protocol inside CDC on CDC ECM like
  47                  * control interfaces.  Userspace access to this is required
  48                  * to configure the accompanying data interface
  49                  */
  50                 .match_flags        = USB_DEVICE_ID_MATCH_VENDOR |
  51                                         USB_DEVICE_ID_MATCH_INT_INFO,
  52                 .idVendor           = HUAWEI_VENDOR_ID,
  53                 .bInterfaceClass    = USB_CLASS_VENDOR_SPEC,
  54                 .bInterfaceSubClass = 1,
  55                 .bInterfaceProtocol = 9, /* NOTE: CDC ECM control interface! */
  56         },
  57         { }
  58 };
  59
  60 MODULE_DEVICE_TABLE (usb, wdm_ids);
  61
  62 #define WDM_MINOR_BASE  176
  63
  64
  65 #define WDM_IN_USE              1
  66 #define WDM_DISCONNECTING       2
  67 #define WDM_RESULT              3
  68 #define WDM_READ                4
  69 #define WDM_INT_STALL           5
  70 #define WDM_POLL_RUNNING        6
  71 #define WDM_RESPONDING          7
  72 #define WDM_SUSPENDING          8
  73 #define WDM_RESETTING           9
  74
  75 #define WDM_MAX                 16
  76
  77 /* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */
  78 #define WDM_DEFAULT_BUFSIZE     256
  79
  80 static DEFINE_MUTEX(wdm_mutex);
  81
  82 /* --- method tables --- */
  83
  84 struct wdm_device {
  85         u8                      *inbuf; /* buffer for response */
  86         u8                      *outbuf; /* buffer for command */
  87         u8                      *sbuf; /* buffer for status */
  88         u8                      *ubuf; /* buffer for copy to user space */
  89
  90         struct urb              *command;
  91         struct urb              *response;
  92         struct urb              *validity;
  93         struct usb_interface    *intf;
  94         struct usb_ctrlrequest  *orq;
  95         struct usb_ctrlrequest  *irq;
  96         spinlock_t              iuspin;
  97
  98         unsigned long           flags;
  99         u16                     bufsize;
 100         u16                     wMaxCommand;
 101         u16                     wMaxPacketSize;
 102         __le16                  inum;
 103         int                     reslength;
 104         int                     length;
 105         int                     read;
 106         int                     count;
 107         dma_addr_t              shandle;
 108         dma_addr_t              ihandle;
 109         struct mutex            wlock;
 110         struct mutex            rlock;
 111         wait_queue_head_t       wait;
 112         struct work_struct      rxwork;
 113         int                     werr;
 114         int                     rerr;
 115 };
 116
 117 static struct usb_driver wdm_driver;
 118
 119 /* --- callbacks --- */
 120 static void wdm_out_callback(struct urb *urb)
 121 {
 122         struct wdm_device *desc;
 123         desc = urb->context;
 124         spin_lock(&desc->iuspin);
 125         desc->werr = urb->status;
 126         spin_unlock(&desc->iuspin);
 127         clear_bit(WDM_IN_USE, &desc->flags);
 128         kfree(desc->outbuf);
 129         wake_up(&desc->wait);
 130 }
 131
 132 static void wdm_in_callback(struct urb *urb)
 133 {
 134         struct wdm_device *desc = urb->context;
 135         int status = urb->status;
 136
 137         spin_lock(&desc->iuspin);
 138         clear_bit(WDM_RESPONDING, &desc->flags);
 139
 140         if (status) {
 141                 switch (status) {
 142                 case -ENOENT:
 143                         dev_dbg(&desc->intf->dev,
 144                                 "nonzero urb status received: -ENOENT");
 145                         goto skip_error;
 146                 case -ECONNRESET:
 147                         dev_dbg(&desc->intf->dev,
 148                                 "nonzero urb status received: -ECONNRESET");
 149                         goto skip_error;
 150                 case -ESHUTDOWN:
 151                         dev_dbg(&desc->intf->dev,
 152                                 "nonzero urb status received: -ESHUTDOWN");
 153                         goto skip_error;
 154                 case -EPIPE:
 155                         dev_err(&desc->intf->dev,
 156                                 "nonzero urb status received: -EPIPE\n");
 157                         break;
 158                 default:
 159                         dev_err(&desc->intf->dev,
 160                                 "Unexpected error %d\n", status);
 161                         break;
 162                 }
 163         }
 164
 165         desc->rerr = status;
 166         desc->reslength = urb->actual_length;
 167         memmove(desc->ubuf + desc->length, desc->inbuf, desc->reslength);
 168         desc->length += desc->reslength;
 169 skip_error:
 170         wake_up(&desc->wait);
 171
 172         set_bit(WDM_READ, &desc->flags);
 173         spin_unlock(&desc->iuspin);
 174 }
 175
 176 static void wdm_int_callback(struct urb *urb)
 177 {
 178         int rv = 0;
 179         int status = urb->status;
 180         struct wdm_device *desc;
 181         struct usb_cdc_notification *dr;
 182
 183         desc = urb->context;
 184         dr = (struct usb_cdc_notification *)desc->sbuf;
 185
 186         if (status) {
 187                 switch (status) {
 188                 case -ESHUTDOWN:
 189                 case -ENOENT:
 190                 case -ECONNRESET:
 191                         return; /* unplug */
 192                 case -EPIPE:
 193                         set_bit(WDM_INT_STALL, &desc->flags);
 194                         dev_err(&desc->intf->dev, "Stall on int endpoint\n");
 195                         goto sw; /* halt is cleared in work */
 196                 default:
 197                         dev_err(&desc->intf->dev,
 198                                 "nonzero urb status received: %d\n", status);
 199                         break;
 200                 }
 201         }
 202
 203         if (urb->actual_length < sizeof(struct usb_cdc_notification)) {
 204                 dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n",
 205                         urb->actual_length);
 206                 goto exit;
 207         }
 208
 209         switch (dr->bNotificationType) {
 210         case USB_CDC_NOTIFY_RESPONSE_AVAILABLE:
 211                 dev_dbg(&desc->intf->dev,
 212                         "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d",
 213                         dr->wIndex, dr->wLength);
 214                 break;
 215
 216         case USB_CDC_NOTIFY_NETWORK_CONNECTION:
 217
 218                 dev_dbg(&desc->intf->dev,
 219                         "NOTIFY_NETWORK_CONNECTION %s network",
 220                         dr->wValue ? "connected to" : "disconnected from");
 221                 goto exit;
 222         default:
 223                 clear_bit(WDM_POLL_RUNNING, &desc->flags);
 224                 dev_err(&desc->intf->dev,
 225                         "unknown notification %d received: index %d len %d\n",
 226                         dr->bNotificationType, dr->wIndex, dr->wLength);
 227                 goto exit;
 228         }
 229
 230         spin_lock(&desc->iuspin);
 231         clear_bit(WDM_READ, &desc->flags);
 232         set_bit(WDM_RESPONDING, &desc->flags);
 233         if (!test_bit(WDM_DISCONNECTING, &desc->flags)
 234                 && !test_bit(WDM_SUSPENDING, &desc->flags)) {
 235                 rv = usb_submit_urb(desc->response, GFP_ATOMIC);
 236                 dev_dbg(&desc->intf->dev, "%s: usb_submit_urb %d",
 237                         __func__, rv);
 238         }
 239         spin_unlock(&desc->iuspin);
 240         if (rv < 0) {
 241                 clear_bit(WDM_RESPONDING, &desc->flags);
 242                 if (rv == -EPERM)
 243                         return;
 244                 if (rv == -ENOMEM) {
 245 sw:
 246                         rv = schedule_work(&desc->rxwork);
 247                         if (rv)
 248                                 dev_err(&desc->intf->dev,
 249                                         "Cannot schedule work\n");
 250                 }
 251         }
 252 exit:
 253         rv = usb_submit_urb(urb, GFP_ATOMIC);
 254         if (rv)
 255                 dev_err(&desc->intf->dev,
 256                         "%s - usb_submit_urb failed with result %d\n",
 257                         __func__, rv);
 258
 259 }
 260
 261 static void kill_urbs(struct wdm_device *desc)
 262 {
 263         /* the order here is essential */
 264         usb_kill_urb(desc->command);
 265         usb_kill_urb(desc->validity);
 266         usb_kill_urb(desc->response);
 267 }
 268
 269 static void free_urbs(struct wdm_device *desc)
 270 {
 271         usb_free_urb(desc->validity);
 272         usb_free_urb(desc->response);
 273         usb_free_urb(desc->command);
 274 }
 275
 276 static void cleanup(struct wdm_device *desc)
 277 {
 278         kfree(desc->sbuf);
 279         kfree(desc->inbuf);
 280         kfree(desc->orq);
 281         kfree(desc->irq);
 282         kfree(desc->ubuf);
 283         free_urbs(desc);
 284         kfree(desc);
 285 }
 286
 287 static ssize_t wdm_write
 288 (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 289 {
 290         u8 *buf;
 291         int rv = -EMSGSIZE, r, we;
 292         struct wdm_device *desc = file->private_data;
 293         struct usb_ctrlrequest *req;
 294
 295         if (count > desc->wMaxCommand)
 296                 count = desc->wMaxCommand;
 297
 298         spin_lock_irq(&desc->iuspin);
 299         we = desc->werr;
 300         desc->werr = 0;
 301         spin_unlock_irq(&desc->iuspin);
 302         if (we < 0)
 303                 return -EIO;
 304
 305         desc->outbuf = buf = kmalloc(count, GFP_KERNEL);
 306         if (!buf) {
 307                 rv = -ENOMEM;
 308                 goto outnl;
 309         }
 310
 311         r = copy_from_user(buf, buffer, count);
 312         if (r > 0) {
 313                 kfree(buf);
 314                 rv = -EFAULT;
 315                 goto outnl;
 316         }
 317
 318         /* concurrent writes and disconnect */
 319         r = mutex_lock_interruptible(&desc->wlock);
 320         rv = -ERESTARTSYS;
 321         if (r) {
 322                 kfree(buf);
 323                 goto outnl;
 324         }
 325
 326         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 327                 kfree(buf);
 328                 rv = -ENODEV;
 329                 goto outnp;
 330         }
 331
 332         r = usb_autopm_get_interface(desc->intf);
 333         if (r < 0) {
 334                 kfree(buf);
 335                 goto outnp;
 336         }
 337
 338         if (!(file->f_flags & O_NONBLOCK))
 339                 r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
 340                                                                 &desc->flags));
 341         else
 342                 if (test_bit(WDM_IN_USE, &desc->flags))
 343                         r = -EAGAIN;
 344
 345         if (test_bit(WDM_RESETTING, &desc->flags))
 346                 r = -EIO;
 347
 348         if (r < 0) {
 349                 kfree(buf);
 350                 goto out;
 351         }
 352
 353         req = desc->orq;
 354         usb_fill_control_urb(
 355                 desc->command,
 356                 interface_to_usbdev(desc->intf),
 357                 /* using common endpoint 0 */
 358                 usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
 359                 (unsigned char *)req,
 360                 buf,
 361                 count,
 362                 wdm_out_callback,
 363                 desc
 364         );
 365
 366         req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
 367                              USB_RECIP_INTERFACE);
 368         req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
 369         req->wValue = 0;
 370         req->wIndex = desc->inum;
 371         req->wLength = cpu_to_le16(count);
 372         set_bit(WDM_IN_USE, &desc->flags);
 373
 374         rv = usb_submit_urb(desc->command, GFP_KERNEL);
 375         if (rv < 0) {
 376                 kfree(buf);
 377                 clear_bit(WDM_IN_USE, &desc->flags);
 378                 dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
 379         } else {
 380                 dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d",
 381                         req->wIndex);
 382         }
 383 out:
 384         usb_autopm_put_interface(desc->intf);
 385 outnp:
 386         mutex_unlock(&desc->wlock);
 387 outnl:
 388         return rv < 0 ? rv : count;
 389 }
 390
 391 static ssize_t wdm_read
 392 (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 393 {
 394         int rv, cntr;
 395         int i = 0;
 396         struct wdm_device *desc = file->private_data;
 397
 398
 399         rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
 400         if (rv < 0)
 401                 return -ERESTARTSYS;
 402
 403         cntr = ACCESS_ONCE(desc->length);
 404         if (cntr == 0) {
 405                 desc->read = 0;
 406 retry:
 407                 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 408                         rv = -ENODEV;
 409                         goto err;
 410                 }
 411                 i++;
 412                 if (file->f_flags & O_NONBLOCK) {
 413                         if (!test_bit(WDM_READ, &desc->flags)) {
 414                                 rv = cntr ? cntr : -EAGAIN;
 415                                 goto err;
 416                         }
 417                         rv = 0;
 418                 } else {
 419                         rv = wait_event_interruptible(desc->wait,
 420                                 test_bit(WDM_READ, &desc->flags));
 421                 }
 422
 423                 /* may have happened while we slept */
 424                 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 425                         rv = -ENODEV;
 426                         goto err;
 427                 }
 428                 if (test_bit(WDM_RESETTING, &desc->flags)) {
 429                         rv = -EIO;
 430                         goto err;
 431                 }
 432                 usb_mark_last_busy(interface_to_usbdev(desc->intf));
 433                 if (rv < 0) {
 434                         rv = -ERESTARTSYS;
 435                         goto err;
 436                 }
 437
 438                 spin_lock_irq(&desc->iuspin);
 439
 440                 if (desc->rerr) { /* read completed, error happened */
 441                         desc->rerr = 0;
 442                         spin_unlock_irq(&desc->iuspin);
 443                         rv = -EIO;
 444                         goto err;
 445                 }
 446                 /*
 447                  * recheck whether we've lost the race
 448                  * against the completion handler
 449                  */
 450                 if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */
 451                         spin_unlock_irq(&desc->iuspin);
 452                         goto retry;
 453                 }
 454                 if (!desc->reslength) { /* zero length read */
 455                         spin_unlock_irq(&desc->iuspin);
 456                         goto retry;
 457                 }
 458                 clear_bit(WDM_READ, &desc->flags);
 459                 cntr = desc->length;
 460                 spin_unlock_irq(&desc->iuspin);
 461         }
 462
 463         if (cntr > count)
 464                 cntr = count;
 465         rv = copy_to_user(buffer, desc->ubuf, cntr);
 466         if (rv > 0) {
 467                 rv = -EFAULT;
 468                 goto err;
 469         }
 470
 471         spin_lock_irq(&desc->iuspin);
 472
 473         for (i = 0; i < desc->length - cntr; i++)
 474                 desc->ubuf[i] = desc->ubuf[i + cntr];
 475
 476         desc->length -= cntr;
 477         /* in case we had outstanding data */
 478         if (!desc->length)
 479                 clear_bit(WDM_READ, &desc->flags);
 480
 481         spin_unlock_irq(&desc->iuspin);
 482
 483         rv = cntr;
 484
 485 err:
 486         mutex_unlock(&desc->rlock);
 487         return rv;
 488 }
 489
 490 static int wdm_flush(struct file *file, fl_owner_t id)
 491 {
 492         struct wdm_device *desc = file->private_data;
 493
 494         wait_event(desc->wait, !test_bit(WDM_IN_USE, &desc->flags));
 495         if (desc->werr < 0)
 496                 dev_err(&desc->intf->dev, "Error in flush path: %d\n",
 497                         desc->werr);
 498
 499         return desc->werr;
 500 }
 501
 502 static unsigned int wdm_poll(struct file *file, struct poll_table_struct *wait)
 503 {
 504         struct wdm_device *desc = file->private_data;
 505         unsigned long flags;
 506         unsigned int mask = 0;
 507
 508         spin_lock_irqsave(&desc->iuspin, flags);
 509         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 510                 mask = POLLERR;
 511                 spin_unlock_irqrestore(&desc->iuspin, flags);
 512                 goto desc_out;
 513         }
 514         if (test_bit(WDM_READ, &desc->flags))
 515                 mask = POLLIN | POLLRDNORM;
 516         if (desc->rerr || desc->werr)
 517                 mask |= POLLERR;
 518         if (!test_bit(WDM_IN_USE, &desc->flags))
 519                 mask |= POLLOUT | POLLWRNORM;
 520         spin_unlock_irqrestore(&desc->iuspin, flags);
 521
 522         poll_wait(file, &desc->wait, wait);
 523
 524 desc_out:
 525         return mask;
 526 }
 527
 528 static int wdm_open(struct inode *inode, struct file *file)
 529 {
 530         int minor = iminor(inode);
 531         int rv = -ENODEV;
 532         struct usb_interface *intf;
 533         struct wdm_device *desc;
 534
 535         mutex_lock(&wdm_mutex);
 536         intf = usb_find_interface(&wdm_driver, minor);
 537         if (!intf)
 538                 goto out;
 539
 540         desc = usb_get_intfdata(intf);
 541         if (test_bit(WDM_DISCONNECTING, &desc->flags))
 542                 goto out;
 543         file->private_data = desc;
 544
 545         rv = usb_autopm_get_interface(desc->intf);
 546         if (rv < 0) {
 547                 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
 548                 goto out;
 549         }
 550         intf->needs_remote_wakeup = 1;
 551
 552         /* using write lock to protect desc->count */
 553         mutex_lock(&desc->wlock);
 554         if (!desc->count++) {
 555                 desc->werr = 0;
 556                 desc->rerr = 0;
 557                 rv = usb_submit_urb(desc->validity, GFP_KERNEL);
 558                 if (rv < 0) {
 559                         desc->count--;
 560                         dev_err(&desc->intf->dev,
 561                                 "Error submitting int urb - %d\n", rv);
 562                 }
 563         } else {
 564                 rv = 0;
 565         }
 566         mutex_unlock(&desc->wlock);
 567         usb_autopm_put_interface(desc->intf);
 568 out:
 569         mutex_unlock(&wdm_mutex);
 570         return rv;
 571 }
 572
 573 static int wdm_release(struct inode *inode, struct file *file)
 574 {
 575         struct wdm_device *desc = file->private_data;
 576
 577         mutex_lock(&wdm_mutex);
 578
 579         /* using write lock to protect desc->count */
 580         mutex_lock(&desc->wlock);
 581         desc->count--;
 582         mutex_unlock(&desc->wlock);
 583
 584         if (!desc->count) {
 585                 dev_dbg(&desc->intf->dev, "wdm_release: cleanup");
 586                 kill_urbs(desc);
 587                 if (!test_bit(WDM_DISCONNECTING, &desc->flags))
 588                         desc->intf->needs_remote_wakeup = 0;
 589         }
 590         mutex_unlock(&wdm_mutex);
 591         return 0;
 592 }
 593
 594 static const struct file_operations wdm_fops = {
 595         .owner =        THIS_MODULE,
 596         .read =         wdm_read,
 597         .write =        wdm_write,
 598         .open =         wdm_open,
 599         .flush =        wdm_flush,
 600         .release =      wdm_release,
 601         .poll =         wdm_poll,
 602         .llseek =       noop_llseek,
 603 };
 604
 605 static struct usb_class_driver wdm_class = {
 606         .name =         "cdc-wdm%d",
 607         .fops =         &wdm_fops,
 608         .minor_base =   WDM_MINOR_BASE,
 609 };
 610
 611 /* --- error handling --- */
 612 static void wdm_rxwork(struct work_struct *work)
 613 {
 614         struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
 615         unsigned long flags;
 616         int rv;
 617
 618         spin_lock_irqsave(&desc->iuspin, flags);
 619         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 620                 spin_unlock_irqrestore(&desc->iuspin, flags);
 621         } else {
 622                 spin_unlock_irqrestore(&desc->iuspin, flags);
 623                 rv = usb_submit_urb(desc->response, GFP_KERNEL);
 624                 if (rv < 0 && rv != -EPERM) {
 625                         spin_lock_irqsave(&desc->iuspin, flags);
 626                         if (!test_bit(WDM_DISCONNECTING, &desc->flags))
 627                                 schedule_work(&desc->rxwork);
 628                         spin_unlock_irqrestore(&desc->iuspin, flags);
 629                 }
 630         }
 631 }
 632
 633 /* --- hotplug --- */
 634
 635 static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
 636 {
 637         int rv = -EINVAL;
 638         struct wdm_device *desc;
 639         struct usb_host_interface *iface;
 640         struct usb_endpoint_descriptor *ep;
 641         struct usb_cdc_dmm_desc *dmhd;
 642         u8 *buffer = intf->altsetting->extra;
 643         int buflen = intf->altsetting->extralen;
 644         u16 maxcom = WDM_DEFAULT_BUFSIZE;
 645
 646         if (!buffer)
 647                 goto out;
 648
 649         while (buflen > 2) {
 650                 if (buffer [1] != USB_DT_CS_INTERFACE) {
 651                         dev_err(&intf->dev, "skipping garbage\n");
 652                         goto next_desc;
 653                 }
 654
 655                 switch (buffer [2]) {
 656                 case USB_CDC_HEADER_TYPE:
 657                         break;
 658                 case USB_CDC_DMM_TYPE:
 659                         dmhd = (struct usb_cdc_dmm_desc *)buffer;
 660                         maxcom = le16_to_cpu(dmhd->wMaxCommand);
 661                         dev_dbg(&intf->dev,
 662                                 "Finding maximum buffer length: %d", maxcom);
 663                         break;
 664                 default:
 665                         dev_err(&intf->dev,
 666                                 "Ignoring extra header, type %d, length %d\n",
 667                                 buffer[2], buffer[0]);
 668                         break;
 669                 }
 670 next_desc:
 671                 buflen -= buffer[0];
 672                 buffer += buffer[0];
 673         }
 674
 675         rv = -ENOMEM;
 676         desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
 677         if (!desc)
 678                 goto out;
 679         mutex_init(&desc->rlock);
 680         mutex_init(&desc->wlock);
 681         spin_lock_init(&desc->iuspin);
 682         init_waitqueue_head(&desc->wait);
 683         desc->wMaxCommand = maxcom;
 684         /* this will be expanded and needed in hardware endianness */
 685         desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
 686         desc->intf = intf;
 687         INIT_WORK(&desc->rxwork, wdm_rxwork);
 688
 689         rv = -EINVAL;
 690         iface = intf->cur_altsetting;
 691         if (iface->desc.bNumEndpoints != 1)
 692                 goto err;
 693         ep = &iface->endpoint[0].desc;
 694         if (!ep || !usb_endpoint_is_int_in(ep))
 695                 goto err;
 696
 697         desc->wMaxPacketSize = usb_endpoint_maxp(ep);
 698
 699         desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
 700         if (!desc->orq)
 701                 goto err;
 702         desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
 703         if (!desc->irq)
 704                 goto err;
 705
 706         desc->validity = usb_alloc_urb(0, GFP_KERNEL);
 707         if (!desc->validity)
 708                 goto err;
 709
 710         desc->response = usb_alloc_urb(0, GFP_KERNEL);
 711         if (!desc->response)
 712                 goto err;
 713
 714         desc->command = usb_alloc_urb(0, GFP_KERNEL);
 715         if (!desc->command)
 716                 goto err;
 717
 718         desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
 719         if (!desc->ubuf)
 720                 goto err;
 721
 722         desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);
 723         if (!desc->sbuf)
 724                 goto err;
 725
 726         desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
 727         if (!desc->inbuf)
 728                 goto err;
 729
 730         usb_fill_int_urb(
 731                 desc->validity,
 732                 interface_to_usbdev(intf),
 733                 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
 734                 desc->sbuf,
 735                 desc->wMaxPacketSize,
 736                 wdm_int_callback,
 737                 desc,
 738                 ep->bInterval
 739         );
 740
 741         desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
 742         desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
 743         desc->irq->wValue = 0;
 744         desc->irq->wIndex = desc->inum;
 745         desc->irq->wLength = cpu_to_le16(desc->wMaxCommand);
 746
 747         usb_fill_control_urb(
 748                 desc->response,
 749                 interface_to_usbdev(intf),
 750                 /* using common endpoint 0 */
 751                 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
 752                 (unsigned char *)desc->irq,
 753                 desc->inbuf,
 754                 desc->wMaxCommand,
 755                 wdm_in_callback,
 756                 desc
 757         );
 758
 759         usb_set_intfdata(intf, desc);
 760         rv = usb_register_dev(intf, &wdm_class);
 761         if (rv < 0)
 762                 goto err2;
 763         else
 764                 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev));
 765 out:
 766         return rv;
 767 err2:
 768         usb_set_intfdata(intf, NULL);
 769 err:
 770         free_urbs(desc);
 771         kfree(desc->inbuf);
 772         kfree(desc->sbuf);
 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         /*
 878          * we notify everybody using poll of
 879          * an exceptional situation
 880          * must be done before recovery lest a spontaneous
 881          * message from the device is lost
 882          */
 883         spin_lock_irq(&desc->iuspin);
 884         set_bit(WDM_RESETTING, &desc->flags);   /* inform read/write */
 885         set_bit(WDM_READ, &desc->flags);        /* unblock read */
 886         clear_bit(WDM_IN_USE, &desc->flags);    /* unblock write */
 887         desc->rerr = -EINTR;
 888         spin_unlock_irq(&desc->iuspin);
 889         wake_up_all(&desc->wait);
 890         mutex_lock(&desc->rlock);
 891         mutex_lock(&desc->wlock);
 892         kill_urbs(desc);
 893         cancel_work_sync(&desc->rxwork);
 894         return 0;
 895 }
 896
 897 static int wdm_post_reset(struct usb_interface *intf)
 898 {
 899         struct wdm_device *desc = usb_get_intfdata(intf);
 900         int rv;
 901
 902         clear_bit(WDM_RESETTING, &desc->flags);
 903         rv = recover_from_urb_loss(desc);
 904         mutex_unlock(&desc->wlock);
 905         mutex_unlock(&desc->rlock);
 906         return 0;
 907 }
 908
 909 static struct usb_driver wdm_driver = {
 910         .name =         "cdc_wdm",
 911         .probe =        wdm_probe,
 912         .disconnect =   wdm_disconnect,
 913 #ifdef CONFIG_PM
 914         .suspend =      wdm_suspend,
 915         .resume =       wdm_resume,
 916         .reset_resume = wdm_resume,
 917 #endif
 918         .pre_reset =    wdm_pre_reset,
 919         .post_reset =   wdm_post_reset,
 920         .id_table =     wdm_ids,
 921         .supports_autosuspend = 1,
 922 };
 923
 924 module_usb_driver(wdm_driver);
 925
 926 MODULE_AUTHOR(DRIVER_AUTHOR);
 927 MODULE_DESCRIPTION(DRIVER_DESC);
 928 MODULE_LICENSE("GPL");