kernel/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, !test_bit(WDM_IN_USE, &desc->flags));
 581
 582         /* cannot dereference desc->intf if WDM_DISCONNECTING */
 583         if (desc->werr < 0 && !test_bit(WDM_DISCONNECTING, &desc->flags))
 584                 dev_err(&desc->intf->dev, "Error in flush path: %d\n",
 585                         desc->werr);
 586
 587         return usb_translate_errors(desc->werr);
 588 }
 589
 590 static unsigned int wdm_poll(struct file *file, struct poll_table_struct *wait)
 591 {
 592         struct wdm_device *desc = file->private_data;
 593         unsigned long flags;
 594         unsigned int mask = 0;
 595
 596         spin_lock_irqsave(&desc->iuspin, flags);
 597         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 598                 mask = POLLHUP | POLLERR;
 599                 spin_unlock_irqrestore(&desc->iuspin, flags);
 600                 goto desc_out;
 601         }
 602         if (test_bit(WDM_READ, &desc->flags))
 603                 mask = POLLIN | POLLRDNORM;
 604         if (desc->rerr || desc->werr)
 605                 mask |= POLLERR;
 606         if (!test_bit(WDM_IN_USE, &desc->flags))
 607                 mask |= POLLOUT | POLLWRNORM;
 608         spin_unlock_irqrestore(&desc->iuspin, flags);
 609
 610         poll_wait(file, &desc->wait, wait);
 611
 612 desc_out:
 613         return mask;
 614 }
 615
 616 static int wdm_open(struct inode *inode, struct file *file)
 617 {
 618         int minor = iminor(inode);
 619         int rv = -ENODEV;
 620         struct usb_interface *intf;
 621         struct wdm_device *desc;
 622
 623         mutex_lock(&wdm_mutex);
 624         desc = wdm_find_device_by_minor(minor);
 625         if (!desc)
 626                 goto out;
 627
 628         intf = desc->intf;
 629         if (test_bit(WDM_DISCONNECTING, &desc->flags))
 630                 goto out;
 631         file->private_data = desc;
 632
 633         rv = usb_autopm_get_interface(desc->intf);
 634         if (rv < 0) {
 635                 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
 636                 goto out;
 637         }
 638
 639         /* using write lock to protect desc->count */
 640         mutex_lock(&desc->wlock);
 641         if (!desc->count++) {
 642                 desc->werr = 0;
 643                 desc->rerr = 0;
 644                 rv = usb_submit_urb(desc->validity, GFP_KERNEL);
 645                 if (rv < 0) {
 646                         desc->count--;
 647                         dev_err(&desc->intf->dev,
 648                                 "Error submitting int urb - %d\n", rv);
 649                         rv = usb_translate_errors(rv);
 650                 }
 651         } else {
 652                 rv = 0;
 653         }
 654         mutex_unlock(&desc->wlock);
 655         if (desc->count == 1)
 656                 desc->manage_power(intf, 1);
 657         usb_autopm_put_interface(desc->intf);
 658 out:
 659         mutex_unlock(&wdm_mutex);
 660         return rv;
 661 }
 662
 663 static int wdm_release(struct inode *inode, struct file *file)
 664 {
 665         struct wdm_device *desc = file->private_data;
 666
 667         mutex_lock(&wdm_mutex);
 668
 669         /* using write lock to protect desc->count */
 670         mutex_lock(&desc->wlock);
 671         desc->count--;
 672         mutex_unlock(&desc->wlock);
 673
 674         if (!desc->count) {
 675                 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
 676                         dev_dbg(&desc->intf->dev, "wdm_release: cleanup");
 677                         kill_urbs(desc);
 678                         spin_lock_irq(&desc->iuspin);
 679                         desc->resp_count = 0;
 680                         spin_unlock_irq(&desc->iuspin);
 681                         desc->manage_power(desc->intf, 0);
 682                 } else {
 683                         /* must avoid dev_printk here as desc->intf is invalid */
 684                         pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
 685                         cleanup(desc);
 686                 }
 687         }
 688         mutex_unlock(&wdm_mutex);
 689         return 0;
 690 }
 691
 692 static long wdm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 693 {
 694         struct wdm_device *desc = file->private_data;
 695         int rv = 0;
 696
 697         switch (cmd) {
 698         case IOCTL_WDM_MAX_COMMAND:
 699                 if (copy_to_user((void __user *)arg, &desc->wMaxCommand, sizeof(desc->wMaxCommand)))
 700                         rv = -EFAULT;
 701                 break;
 702         default:
 703                 rv = -ENOTTY;
 704         }
 705         return rv;
 706 }
 707
 708 static const struct file_operations wdm_fops = {
 709         .owner =        THIS_MODULE,
 710         .read =         wdm_read,
 711         .write =        wdm_write,
 712         .open =         wdm_open,
 713         .flush =        wdm_flush,
 714         .release =      wdm_release,
 715         .poll =         wdm_poll,
 716         .unlocked_ioctl = wdm_ioctl,
 717         .compat_ioctl = wdm_ioctl,
 718         .llseek =       noop_llseek,
 719 };
 720
 721 static struct usb_class_driver wdm_class = {
 722         .name =         "cdc-wdm%d",
 723         .fops =         &wdm_fops,
 724         .minor_base =   WDM_MINOR_BASE,
 725 };
 726
 727 /* --- error handling --- */
 728 static void wdm_rxwork(struct work_struct *work)
 729 {
 730         struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
 731         unsigned long flags;
 732         int rv = 0;
 733         int responding;
 734
 735         spin_lock_irqsave(&desc->iuspin, flags);
 736         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 737                 spin_unlock_irqrestore(&desc->iuspin, flags);
 738         } else {
 739                 responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
 740                 spin_unlock_irqrestore(&desc->iuspin, flags);
 741                 if (!responding)
 742                         rv = usb_submit_urb(desc->response, GFP_KERNEL);
 743                 if (rv < 0 && rv != -EPERM) {
 744                         spin_lock_irqsave(&desc->iuspin, flags);
 745                         clear_bit(WDM_RESPONDING, &desc->flags);
 746                         if (!test_bit(WDM_DISCONNECTING, &desc->flags))
 747                                 schedule_work(&desc->rxwork);
 748                         spin_unlock_irqrestore(&desc->iuspin, flags);
 749                 }
 750         }
 751 }
 752
 753 /* --- hotplug --- */
 754
 755 static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
 756                 u16 bufsize, int (*manage_power)(struct usb_interface *, int))
 757 {
 758         int rv = -ENOMEM;
 759         struct wdm_device *desc;
 760
 761         desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
 762         if (!desc)
 763                 goto out;
 764         INIT_LIST_HEAD(&desc->device_list);
 765         mutex_init(&desc->rlock);
 766         mutex_init(&desc->wlock);
 767         spin_lock_init(&desc->iuspin);
 768         init_waitqueue_head(&desc->wait);
 769         desc->wMaxCommand = bufsize;
 770         /* this will be expanded and needed in hardware endianness */
 771         desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
 772         desc->intf = intf;
 773         INIT_WORK(&desc->rxwork, wdm_rxwork);
 774
 775         rv = -EINVAL;
 776         if (!usb_endpoint_is_int_in(ep))
 777                 goto err;
 778
 779         desc->wMaxPacketSize = usb_endpoint_maxp(ep);
 780
 781         desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
 782         if (!desc->orq)
 783                 goto err;
 784         desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
 785         if (!desc->irq)
 786                 goto err;
 787
 788         desc->validity = usb_alloc_urb(0, GFP_KERNEL);
 789         if (!desc->validity)
 790                 goto err;
 791
 792         desc->response = usb_alloc_urb(0, GFP_KERNEL);
 793         if (!desc->response)
 794                 goto err;
 795
 796         desc->command = usb_alloc_urb(0, GFP_KERNEL);
 797         if (!desc->command)
 798                 goto err;
 799
 800         desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
 801         if (!desc->ubuf)
 802                 goto err;
 803
 804         desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);
 805         if (!desc->sbuf)
 806                 goto err;
 807
 808         desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
 809         if (!desc->inbuf)
 810                 goto err;
 811
 812         usb_fill_int_urb(
 813                 desc->validity,
 814                 interface_to_usbdev(intf),
 815                 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
 816                 desc->sbuf,
 817                 desc->wMaxPacketSize,
 818                 wdm_int_callback,
 819                 desc,
 820                 ep->bInterval
 821         );
 822
 823         desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
 824         desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
 825         desc->irq->wValue = 0;
 826         desc->irq->wIndex = desc->inum; /* already converted */
 827         desc->irq->wLength = cpu_to_le16(desc->wMaxCommand);
 828
 829         usb_fill_control_urb(
 830                 desc->response,
 831                 interface_to_usbdev(intf),
 832                 /* using common endpoint 0 */
 833                 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
 834                 (unsigned char *)desc->irq,
 835                 desc->inbuf,
 836                 desc->wMaxCommand,
 837                 wdm_in_callback,
 838                 desc
 839         );
 840
 841         desc->manage_power = manage_power;
 842
 843         spin_lock(&wdm_device_list_lock);
 844         list_add(&desc->device_list, &wdm_device_list);
 845         spin_unlock(&wdm_device_list_lock);
 846
 847         rv = usb_register_dev(intf, &wdm_class);
 848         if (rv < 0)
 849                 goto err;
 850         else
 851                 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev));
 852 out:
 853         return rv;
 854 err:
 855         spin_lock(&wdm_device_list_lock);
 856         list_del(&desc->device_list);
 857         spin_unlock(&wdm_device_list_lock);
 858         cleanup(desc);
 859         return rv;
 860 }
 861
 862 static int wdm_manage_power(struct usb_interface *intf, int on)
 863 {
 864         /* need autopm_get/put here to ensure the usbcore sees the new value */
 865         int rv = usb_autopm_get_interface(intf);
 866
 867         intf->needs_remote_wakeup = on;
 868         if (!rv)
 869                 usb_autopm_put_interface(intf);
 870         return 0;
 871 }
 872
 873 static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
 874 {
 875         int rv = -EINVAL;
 876         struct usb_host_interface *iface;
 877         struct usb_endpoint_descriptor *ep;
 878         struct usb_cdc_dmm_desc *dmhd;
 879         u8 *buffer = intf->altsetting->extra;
 880         int buflen = intf->altsetting->extralen;
 881         u16 maxcom = WDM_DEFAULT_BUFSIZE;
 882
 883         if (!buffer)
 884                 goto err;
 885         while (buflen > 2) {
 886                 if (buffer[1] != USB_DT_CS_INTERFACE) {
 887                         dev_err(&intf->dev, "skipping garbage\n");
 888                         goto next_desc;
 889                 }
 890
 891                 switch (buffer[2]) {
 892                 case USB_CDC_HEADER_TYPE:
 893                         break;
 894                 case USB_CDC_DMM_TYPE:
 895                         dmhd = (struct usb_cdc_dmm_desc *)buffer;
 896                         maxcom = le16_to_cpu(dmhd->wMaxCommand);
 897                         dev_dbg(&intf->dev,
 898                                 "Finding maximum buffer length: %d", maxcom);
 899                         break;
 900                 default:
 901                         dev_err(&intf->dev,
 902                                 "Ignoring extra header, type %d, length %d\n",
 903                                 buffer[2], buffer[0]);
 904                         break;
 905                 }
 906 next_desc:
 907                 buflen -= buffer[0];
 908                 buffer += buffer[0];
 909         }
 910
 911         iface = intf->cur_altsetting;
 912         if (iface->desc.bNumEndpoints != 1)
 913                 goto err;
 914         ep = &iface->endpoint[0].desc;
 915
 916         rv = wdm_create(intf, ep, maxcom, &wdm_manage_power);
 917
 918 err:
 919         return rv;
 920 }
 921
 922 /**
 923  * usb_cdc_wdm_register - register a WDM subdriver
 924  * @intf: usb interface the subdriver will associate with
 925  * @ep: interrupt endpoint to monitor for notifications
 926  * @bufsize: maximum message size to support for read/write
 927  *
 928  * Create WDM usb class character device and associate it with intf
 929  * without binding, allowing another driver to manage the interface.
 930  *
 931  * The subdriver will manage the given interrupt endpoint exclusively
 932  * and will issue control requests referring to the given intf. It
 933  * will otherwise avoid interferring, and in particular not do
 934  * usb_set_intfdata/usb_get_intfdata on intf.
 935  *
 936  * The return value is a pointer to the subdriver's struct usb_driver.
 937  * The registering driver is responsible for calling this subdriver's
 938  * disconnect, suspend, resume, pre_reset and post_reset methods from
 939  * its own.
 940  */
 941 struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,
 942                                         struct usb_endpoint_descriptor *ep,
 943                                         int bufsize,
 944                                         int (*manage_power)(struct usb_interface *, int))
 945 {
 946         int rv = -EINVAL;
 947
 948         rv = wdm_create(intf, ep, bufsize, manage_power);
 949         if (rv < 0)
 950                 goto err;
 951
 952         return &wdm_driver;
 953 err:
 954         return ERR_PTR(rv);
 955 }
 956 EXPORT_SYMBOL(usb_cdc_wdm_register);
 957
 958 static void wdm_disconnect(struct usb_interface *intf)
 959 {
 960         struct wdm_device *desc;
 961         unsigned long flags;
 962
 963         usb_deregister_dev(intf, &wdm_class);
 964         desc = wdm_find_device(intf);
 965         mutex_lock(&wdm_mutex);
 966
 967         /* the spinlock makes sure no new urbs are generated in the callbacks */
 968         spin_lock_irqsave(&desc->iuspin, flags);
 969         set_bit(WDM_DISCONNECTING, &desc->flags);
 970         set_bit(WDM_READ, &desc->flags);
 971         /* to terminate pending flushes */
 972         clear_bit(WDM_IN_USE, &desc->flags);
 973         spin_unlock_irqrestore(&desc->iuspin, flags);
 974         wake_up_all(&desc->wait);
 975         mutex_lock(&desc->rlock);
 976         mutex_lock(&desc->wlock);
 977         kill_urbs(desc);
 978         cancel_work_sync(&desc->rxwork);
 979         mutex_unlock(&desc->wlock);
 980         mutex_unlock(&desc->rlock);
 981
 982         /* the desc->intf pointer used as list key is now invalid */
 983         spin_lock(&wdm_device_list_lock);
 984         list_del(&desc->device_list);
 985         spin_unlock(&wdm_device_list_lock);
 986
 987         if (!desc->count)
 988                 cleanup(desc);
 989         else
 990                 dev_dbg(&intf->dev, "%s: %d open files - postponing cleanup\n", __func__, desc->count);
 991         mutex_unlock(&wdm_mutex);
 992 }
 993
 994 #ifdef CONFIG_PM
 995 static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
 996 {
 997         struct wdm_device *desc = wdm_find_device(intf);
 998         int rv = 0;
 999
1000         dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
1001
1002         /* if this is an autosuspend the caller does the locking */
1003         if (!PMSG_IS_AUTO(message)) {
1004                 mutex_lock(&desc->rlock);
1005                 mutex_lock(&desc->wlock);
1006         }
1007         spin_lock_irq(&desc->iuspin);
1008
1009         if (PMSG_IS_AUTO(message) &&
1010                         (test_bit(WDM_IN_USE, &desc->flags)
1011                         || test_bit(WDM_RESPONDING, &desc->flags))) {
1012                 spin_unlock_irq(&desc->iuspin);
1013                 rv = -EBUSY;
1014         } else {
1015
1016                 set_bit(WDM_SUSPENDING, &desc->flags);
1017                 spin_unlock_irq(&desc->iuspin);
1018                 /* callback submits work - order is essential */
1019                 kill_urbs(desc);
1020                 cancel_work_sync(&desc->rxwork);
1021         }
1022         if (!PMSG_IS_AUTO(message)) {
1023                 mutex_unlock(&desc->wlock);
1024                 mutex_unlock(&desc->rlock);
1025         }
1026
1027         return rv;
1028 }
1029 #endif
1030
1031 static int recover_from_urb_loss(struct wdm_device *desc)
1032 {
1033         int rv = 0;
1034
1035         if (desc->count) {
1036                 rv = usb_submit_urb(desc->validity, GFP_NOIO);
1037                 if (rv < 0)
1038                         dev_err(&desc->intf->dev,
1039                                 "Error resume submitting int urb - %d\n", rv);
1040         }
1041         return rv;
1042 }
1043
1044 #ifdef CONFIG_PM
1045 static int wdm_resume(struct usb_interface *intf)
1046 {
1047         struct wdm_device *desc = wdm_find_device(intf);
1048         int rv;
1049
1050         dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
1051
1052         clear_bit(WDM_SUSPENDING, &desc->flags);
1053         rv = recover_from_urb_loss(desc);
1054
1055         return rv;
1056 }
1057 #endif
1058
1059 static int wdm_pre_reset(struct usb_interface *intf)
1060 {
1061         struct wdm_device *desc = wdm_find_device(intf);
1062
1063         /*
1064          * we notify everybody using poll of
1065          * an exceptional situation
1066          * must be done before recovery lest a spontaneous
1067          * message from the device is lost
1068          */
1069         spin_lock_irq(&desc->iuspin);
1070         set_bit(WDM_RESETTING, &desc->flags);   /* inform read/write */
1071         set_bit(WDM_READ, &desc->flags);        /* unblock read */
1072         clear_bit(WDM_IN_USE, &desc->flags);    /* unblock write */
1073         desc->rerr = -EINTR;
1074         spin_unlock_irq(&desc->iuspin);
1075         wake_up_all(&desc->wait);
1076         mutex_lock(&desc->rlock);
1077         mutex_lock(&desc->wlock);
1078         kill_urbs(desc);
1079         cancel_work_sync(&desc->rxwork);
1080         return 0;
1081 }
1082
1083 static int wdm_post_reset(struct usb_interface *intf)
1084 {
1085         struct wdm_device *desc = wdm_find_device(intf);
1086         int rv;
1087
1088         clear_bit(WDM_OVERFLOW, &desc->flags);
1089         clear_bit(WDM_RESETTING, &desc->flags);
1090         rv = recover_from_urb_loss(desc);
1091         mutex_unlock(&desc->wlock);
1092         mutex_unlock(&desc->rlock);
1093         return 0;
1094 }
1095
1096 static struct usb_driver wdm_driver = {
1097         .name =         "cdc_wdm",
1098         .probe =        wdm_probe,
1099         .disconnect =   wdm_disconnect,
1100 #ifdef CONFIG_PM
1101         .suspend =      wdm_suspend,
1102         .resume =       wdm_resume,
1103         .reset_resume = wdm_resume,
1104 #endif
1105         .pre_reset =    wdm_pre_reset,
1106         .post_reset =   wdm_post_reset,
1107         .id_table =     wdm_ids,
1108         .supports_autosuspend = 1,
1109         .disable_hub_initiated_lpm = 1,
1110 };
1111
1112 module_usb_driver(wdm_driver);
1113
1114 MODULE_AUTHOR(DRIVER_AUTHOR);
1115 MODULE_DESCRIPTION(DRIVER_DESC);
1116 MODULE_LICENSE("GPL");