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                         dr->wIndex, 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, dr->wIndex, dr->wLength);
 266                 goto exit;
 267         }
 268
 269         spin_lock(&desc->iuspin);
 270         responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
 271         if (!desc->resp_count++ && !responding
 272                 && !test_bit(WDM_DISCONNECTING, &desc->flags)
 273                 && !test_bit(WDM_SUSPENDING, &desc->flags)) {
 274                 rv = usb_submit_urb(desc->response, GFP_ATOMIC);
 275                 dev_dbg(&desc->intf->dev, "%s: usb_submit_urb %d",
 276                         __func__, rv);
 277         }
 278         spin_unlock(&desc->iuspin);
 279         if (rv < 0) {
 280                 clear_bit(WDM_RESPONDING, &desc->flags);
 281                 if (rv == -EPERM)
 282                         return;
 283                 if (rv == -ENOMEM) {
 284 sw:
 285                         rv = schedule_work(&desc->rxwork);
 286                         if (rv)
 287                                 dev_err(&desc->intf->dev,
 288                                         "Cannot schedule work\n");
 289                 }
 290         }
 291 exit:
 292         rv = usb_submit_urb(urb, GFP_ATOMIC);
 293         if (rv)
 294                 dev_err(&desc->intf->dev,
 295                         "%s - usb_submit_urb failed with result %d\n",
 296                         __func__, rv);
 297
 298 }
 299
 300 static void kill_urbs(struct wdm_device *desc)
 301 {
 302         /* the order here is essential */
 303         usb_kill_urb(desc->command);
 304         usb_kill_urb(desc->validity);
 305         usb_kill_urb(desc->response);
 306 }
 307
 308 static void free_urbs(struct wdm_device *desc)
 309 {
 310         usb_free_urb(desc->validity);
 311         usb_free_urb(desc->response);
 312         usb_free_urb(desc->command);
 313 }
 314
 315 static void cleanup(struct wdm_device *desc)
 316 {
 317         kfree(desc->sbuf);
 318         kfree(desc->inbuf);
 319         kfree(desc->orq);
 320         kfree(desc->irq);
 321         kfree(desc->ubuf);
 322         free_urbs(desc);
 323         kfree(desc);
 324 }
 325
 326 static ssize_t wdm_write
 327 (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 328 {
 329         u8 *buf;
 330         int rv = -EMSGSIZE, r, we;
 331         struct wdm_device *desc = file->private_data;
 332         struct usb_ctrlrequest *req;
 333
 334         if (count > desc->wMaxCommand)
 335                 count = desc->wMaxCommand;
 336
 337         spin_lock_irq(&desc->iuspin);
 338         we = desc->werr;
 339         desc->werr = 0;
 340         spin_unlock_irq(&desc->iuspin);
 341         if (we < 0)
 342                 return -EIO;
 343
 344         buf = kmalloc(count, GFP_KERNEL);
 345         if (!buf) {
 346                 rv = -ENOMEM;
 347                 goto outnl;
 348         }
 349
 350         r = copy_from_user(buf, buffer, count);
 351         if (r > 0) {
 352                 kfree(buf);
 353                 rv = -EFAULT;
 354                 goto outnl;
 355         }
 356
 357         /* concurrent writes and disconnect */
 358         r = mutex_lock_interruptible(&desc->wlock);
 359         rv = -ERESTARTSYS;
 360         if (r) {
 361                 kfree(buf);
 362                 goto outnl;
 363         }
 364
 365         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 366                 kfree(buf);
 367                 rv = -ENODEV;
 368                 goto outnp;
 369         }
 370
 371         r = usb_autopm_get_interface(desc->intf);
 372         if (r < 0) {
 373                 kfree(buf);
 374                 rv = usb_translate_errors(r);
 375                 goto outnp;
 376         }
 377
 378         if (!(file->f_flags & O_NONBLOCK))
 379                 r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
 380                                                                 &desc->flags));
 381         else
 382                 if (test_bit(WDM_IN_USE, &desc->flags))
 383                         r = -EAGAIN;
 384
 385         if (test_bit(WDM_RESETTING, &desc->flags))
 386                 r = -EIO;
 387
 388         if (r < 0) {
 389                 kfree(buf);
 390                 rv = r;
 391                 goto out;
 392         }
 393
 394         req = desc->orq;
 395         usb_fill_control_urb(
 396                 desc->command,
 397                 interface_to_usbdev(desc->intf),
 398                 /* using common endpoint 0 */
 399                 usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
 400                 (unsigned char *)req,
 401                 buf,
 402                 count,
 403                 wdm_out_callback,
 404                 desc
 405         );
 406
 407         req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
 408                              USB_RECIP_INTERFACE);
 409         req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
 410         req->wValue = 0;
 411         req->wIndex = desc->inum;
 412         req->wLength = cpu_to_le16(count);
 413         set_bit(WDM_IN_USE, &desc->flags);
 414         desc->outbuf = buf;
 415
 416         rv = usb_submit_urb(desc->command, GFP_KERNEL);
 417         if (rv < 0) {
 418                 kfree(buf);
 419                 desc->outbuf = NULL;
 420                 clear_bit(WDM_IN_USE, &desc->flags);
 421                 dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
 422                 rv = usb_translate_errors(rv);
 423         } else {
 424                 dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d",
 425                         req->wIndex);
 426         }
 427 out:
 428         usb_autopm_put_interface(desc->intf);
 429 outnp:
 430         mutex_unlock(&desc->wlock);
 431 outnl:
 432         return rv < 0 ? rv : count;
 433 }
 434
 435 /*
 436  * clear WDM_READ flag and possibly submit the read urb if resp_count
 437  * is non-zero.
 438  *
 439  * Called with desc->iuspin locked
 440  */
 441 static int clear_wdm_read_flag(struct wdm_device *desc)
 442 {
 443         int rv = 0;
 444
 445         clear_bit(WDM_READ, &desc->flags);
 446
 447         /* submit read urb only if the device is waiting for it */
 448         if (!desc->resp_count || !--desc->resp_count)
 449                 goto out;
 450
 451         set_bit(WDM_RESPONDING, &desc->flags);
 452         spin_unlock_irq(&desc->iuspin);
 453         rv = usb_submit_urb(desc->response, GFP_KERNEL);
 454         spin_lock_irq(&desc->iuspin);
 455         if (rv) {
 456                 dev_err(&desc->intf->dev,
 457                         "usb_submit_urb failed with result %d\n", rv);
 458
 459                 /* make sure the next notification trigger a submit */
 460                 clear_bit(WDM_RESPONDING, &desc->flags);
 461                 desc->resp_count = 0;
 462         }
 463 out:
 464         return rv;
 465 }
 466
 467 static ssize_t wdm_read
 468 (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 469 {
 470         int rv, cntr;
 471         int i = 0;
 472         struct wdm_device *desc = file->private_data;
 473
 474
 475         rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
 476         if (rv < 0)
 477                 return -ERESTARTSYS;
 478
 479         cntr = ACCESS_ONCE(desc->length);
 480         if (cntr == 0) {
 481                 desc->read = 0;
 482 retry:
 483                 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 484                         rv = -ENODEV;
 485                         goto err;
 486                 }
 487                 if (test_bit(WDM_OVERFLOW, &desc->flags)) {
 488                         clear_bit(WDM_OVERFLOW, &desc->flags);
 489                         rv = -ENOBUFS;
 490                         goto err;
 491                 }
 492                 i++;
 493                 if (file->f_flags & O_NONBLOCK) {
 494                         if (!test_bit(WDM_READ, &desc->flags)) {
 495                                 rv = cntr ? cntr : -EAGAIN;
 496                                 goto err;
 497                         }
 498                         rv = 0;
 499                 } else {
 500                         rv = wait_event_interruptible(desc->wait,
 501                                 test_bit(WDM_READ, &desc->flags));
 502                 }
 503
 504                 /* may have happened while we slept */
 505                 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 506                         rv = -ENODEV;
 507                         goto err;
 508                 }
 509                 if (test_bit(WDM_RESETTING, &desc->flags)) {
 510                         rv = -EIO;
 511                         goto err;
 512                 }
 513                 usb_mark_last_busy(interface_to_usbdev(desc->intf));
 514                 if (rv < 0) {
 515                         rv = -ERESTARTSYS;
 516                         goto err;
 517                 }
 518
 519                 spin_lock_irq(&desc->iuspin);
 520
 521                 if (desc->rerr) { /* read completed, error happened */
 522                         desc->rerr = 0;
 523                         spin_unlock_irq(&desc->iuspin);
 524                         rv = -EIO;
 525                         goto err;
 526                 }
 527                 /*
 528                  * recheck whether we've lost the race
 529                  * against the completion handler
 530                  */
 531                 if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */
 532                         spin_unlock_irq(&desc->iuspin);
 533                         goto retry;
 534                 }
 535
 536                 if (!desc->reslength) { /* zero length read */
 537                         dev_dbg(&desc->intf->dev, "%s: zero length - clearing WDM_READ\n", __func__);
 538                         rv = clear_wdm_read_flag(desc);
 539                         spin_unlock_irq(&desc->iuspin);
 540                         if (rv < 0)
 541                                 goto err;
 542                         goto retry;
 543                 }
 544                 cntr = desc->length;
 545                 spin_unlock_irq(&desc->iuspin);
 546         }
 547
 548         if (cntr > count)
 549                 cntr = count;
 550         rv = copy_to_user(buffer, desc->ubuf, cntr);
 551         if (rv > 0) {
 552                 rv = -EFAULT;
 553                 goto err;
 554         }
 555
 556         spin_lock_irq(&desc->iuspin);
 557
 558         for (i = 0; i < desc->length - cntr; i++)
 559                 desc->ubuf[i] = desc->ubuf[i + cntr];
 560
 561         desc->length -= cntr;
 562         /* in case we had outstanding data */
 563         if (!desc->length)
 564                 clear_wdm_read_flag(desc);
 565         spin_unlock_irq(&desc->iuspin);
 566         rv = cntr;
 567
 568 err:
 569         mutex_unlock(&desc->rlock);
 570         return rv;
 571 }
 572
 573 static int wdm_flush(struct file *file, fl_owner_t id)
 574 {
 575         struct wdm_device *desc = file->private_data;
 576
 577         wait_event(desc->wait, !test_bit(WDM_IN_USE, &desc->flags));
 578
 579         /* cannot dereference desc->intf if WDM_DISCONNECTING */
 580         if (desc->werr < 0 && !test_bit(WDM_DISCONNECTING, &desc->flags))
 581                 dev_err(&desc->intf->dev, "Error in flush path: %d\n",
 582                         desc->werr);
 583
 584         return usb_translate_errors(desc->werr);
 585 }
 586
 587 static unsigned int wdm_poll(struct file *file, struct poll_table_struct *wait)
 588 {
 589         struct wdm_device *desc = file->private_data;
 590         unsigned long flags;
 591         unsigned int mask = 0;
 592
 593         spin_lock_irqsave(&desc->iuspin, flags);
 594         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 595                 mask = POLLHUP | POLLERR;
 596                 spin_unlock_irqrestore(&desc->iuspin, flags);
 597                 goto desc_out;
 598         }
 599         if (test_bit(WDM_READ, &desc->flags))
 600                 mask = POLLIN | POLLRDNORM;
 601         if (desc->rerr || desc->werr)
 602                 mask |= POLLERR;
 603         if (!test_bit(WDM_IN_USE, &desc->flags))
 604                 mask |= POLLOUT | POLLWRNORM;
 605         spin_unlock_irqrestore(&desc->iuspin, flags);
 606
 607         poll_wait(file, &desc->wait, wait);
 608
 609 desc_out:
 610         return mask;
 611 }
 612
 613 static int wdm_open(struct inode *inode, struct file *file)
 614 {
 615         int minor = iminor(inode);
 616         int rv = -ENODEV;
 617         struct usb_interface *intf;
 618         struct wdm_device *desc;
 619
 620         mutex_lock(&wdm_mutex);
 621         desc = wdm_find_device_by_minor(minor);
 622         if (!desc)
 623                 goto out;
 624
 625         intf = desc->intf;
 626         if (test_bit(WDM_DISCONNECTING, &desc->flags))
 627                 goto out;
 628         file->private_data = desc;
 629
 630         rv = usb_autopm_get_interface(desc->intf);
 631         if (rv < 0) {
 632                 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
 633                 goto out;
 634         }
 635
 636         /* using write lock to protect desc->count */
 637         mutex_lock(&desc->wlock);
 638         if (!desc->count++) {
 639                 desc->werr = 0;
 640                 desc->rerr = 0;
 641                 rv = usb_submit_urb(desc->validity, GFP_KERNEL);
 642                 if (rv < 0) {
 643                         desc->count--;
 644                         dev_err(&desc->intf->dev,
 645                                 "Error submitting int urb - %d\n", rv);
 646                         rv = usb_translate_errors(rv);
 647                 }
 648         } else {
 649                 rv = 0;
 650         }
 651         mutex_unlock(&desc->wlock);
 652         if (desc->count == 1)
 653                 desc->manage_power(intf, 1);
 654         usb_autopm_put_interface(desc->intf);
 655 out:
 656         mutex_unlock(&wdm_mutex);
 657         return rv;
 658 }
 659
 660 static int wdm_release(struct inode *inode, struct file *file)
 661 {
 662         struct wdm_device *desc = file->private_data;
 663
 664         mutex_lock(&wdm_mutex);
 665
 666         /* using write lock to protect desc->count */
 667         mutex_lock(&desc->wlock);
 668         desc->count--;
 669         mutex_unlock(&desc->wlock);
 670
 671         if (!desc->count) {
 672                 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
 673                         dev_dbg(&desc->intf->dev, "wdm_release: cleanup");
 674                         kill_urbs(desc);
 675                         spin_lock_irq(&desc->iuspin);
 676                         desc->resp_count = 0;
 677                         spin_unlock_irq(&desc->iuspin);
 678                         desc->manage_power(desc->intf, 0);
 679                 } else {
 680                         /* must avoid dev_printk here as desc->intf is invalid */
 681                         pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
 682                         cleanup(desc);
 683                 }
 684         }
 685         mutex_unlock(&wdm_mutex);
 686         return 0;
 687 }
 688
 689 static long wdm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 690 {
 691         struct wdm_device *desc = file->private_data;
 692         int rv = 0;
 693
 694         switch (cmd) {
 695         case IOCTL_WDM_MAX_COMMAND:
 696                 if (copy_to_user((void __user *)arg, &desc->wMaxCommand, sizeof(desc->wMaxCommand)))
 697                         rv = -EFAULT;
 698                 break;
 699         default:
 700                 rv = -ENOTTY;
 701         }
 702         return rv;
 703 }
 704
 705 static const struct file_operations wdm_fops = {
 706         .owner =        THIS_MODULE,
 707         .read =         wdm_read,
 708         .write =        wdm_write,
 709         .open =         wdm_open,
 710         .flush =        wdm_flush,
 711         .release =      wdm_release,
 712         .poll =         wdm_poll,
 713         .unlocked_ioctl = wdm_ioctl,
 714         .compat_ioctl = wdm_ioctl,
 715         .llseek =       noop_llseek,
 716 };
 717
 718 static struct usb_class_driver wdm_class = {
 719         .name =         "cdc-wdm%d",
 720         .fops =         &wdm_fops,
 721         .minor_base =   WDM_MINOR_BASE,
 722 };
 723
 724 /* --- error handling --- */
 725 static void wdm_rxwork(struct work_struct *work)
 726 {
 727         struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
 728         unsigned long flags;
 729         int rv = 0;
 730         int responding;
 731
 732         spin_lock_irqsave(&desc->iuspin, flags);
 733         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 734                 spin_unlock_irqrestore(&desc->iuspin, flags);
 735         } else {
 736                 responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
 737                 spin_unlock_irqrestore(&desc->iuspin, flags);
 738                 if (!responding)
 739                         rv = usb_submit_urb(desc->response, GFP_KERNEL);
 740                 if (rv < 0 && rv != -EPERM) {
 741                         spin_lock_irqsave(&desc->iuspin, flags);
 742                         clear_bit(WDM_RESPONDING, &desc->flags);
 743                         if (!test_bit(WDM_DISCONNECTING, &desc->flags))
 744                                 schedule_work(&desc->rxwork);
 745                         spin_unlock_irqrestore(&desc->iuspin, flags);
 746                 }
 747         }
 748 }
 749
 750 /* --- hotplug --- */
 751
 752 static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
 753                 u16 bufsize, int (*manage_power)(struct usb_interface *, int))
 754 {
 755         int rv = -ENOMEM;
 756         struct wdm_device *desc;
 757
 758         desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
 759         if (!desc)
 760                 goto out;
 761         INIT_LIST_HEAD(&desc->device_list);
 762         mutex_init(&desc->rlock);
 763         mutex_init(&desc->wlock);
 764         spin_lock_init(&desc->iuspin);
 765         init_waitqueue_head(&desc->wait);
 766         desc->wMaxCommand = bufsize;
 767         /* this will be expanded and needed in hardware endianness */
 768         desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
 769         desc->intf = intf;
 770         INIT_WORK(&desc->rxwork, wdm_rxwork);
 771
 772         rv = -EINVAL;
 773         if (!usb_endpoint_is_int_in(ep))
 774                 goto err;
 775
 776         desc->wMaxPacketSize = usb_endpoint_maxp(ep);
 777
 778         desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
 779         if (!desc->orq)
 780                 goto err;
 781         desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
 782         if (!desc->irq)
 783                 goto err;
 784
 785         desc->validity = usb_alloc_urb(0, GFP_KERNEL);
 786         if (!desc->validity)
 787                 goto err;
 788
 789         desc->response = usb_alloc_urb(0, GFP_KERNEL);
 790         if (!desc->response)
 791                 goto err;
 792
 793         desc->command = usb_alloc_urb(0, GFP_KERNEL);
 794         if (!desc->command)
 795                 goto err;
 796
 797         desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
 798         if (!desc->ubuf)
 799                 goto err;
 800
 801         desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);
 802         if (!desc->sbuf)
 803                 goto err;
 804
 805         desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
 806         if (!desc->inbuf)
 807                 goto err;
 808
 809         usb_fill_int_urb(
 810                 desc->validity,
 811                 interface_to_usbdev(intf),
 812                 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
 813                 desc->sbuf,
 814                 desc->wMaxPacketSize,
 815                 wdm_int_callback,
 816                 desc,
 817                 ep->bInterval
 818         );
 819
 820         desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
 821         desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
 822         desc->irq->wValue = 0;
 823         desc->irq->wIndex = desc->inum;
 824         desc->irq->wLength = cpu_to_le16(desc->wMaxCommand);
 825
 826         usb_fill_control_urb(
 827                 desc->response,
 828                 interface_to_usbdev(intf),
 829                 /* using common endpoint 0 */
 830                 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
 831                 (unsigned char *)desc->irq,
 832                 desc->inbuf,
 833                 desc->wMaxCommand,
 834                 wdm_in_callback,
 835                 desc
 836         );
 837
 838         desc->manage_power = manage_power;
 839
 840         spin_lock(&wdm_device_list_lock);
 841         list_add(&desc->device_list, &wdm_device_list);
 842         spin_unlock(&wdm_device_list_lock);
 843
 844         rv = usb_register_dev(intf, &wdm_class);
 845         if (rv < 0)
 846                 goto err;
 847         else
 848                 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev));
 849 out:
 850         return rv;
 851 err:
 852         spin_lock(&wdm_device_list_lock);
 853         list_del(&desc->device_list);
 854         spin_unlock(&wdm_device_list_lock);
 855         cleanup(desc);
 856         return rv;
 857 }
 858
 859 static int wdm_manage_power(struct usb_interface *intf, int on)
 860 {
 861         /* need autopm_get/put here to ensure the usbcore sees the new value */
 862         int rv = usb_autopm_get_interface(intf);
 863
 864         intf->needs_remote_wakeup = on;
 865         if (!rv)
 866                 usb_autopm_put_interface(intf);
 867         return 0;
 868 }
 869
 870 static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
 871 {
 872         int rv = -EINVAL;
 873         struct usb_host_interface *iface;
 874         struct usb_endpoint_descriptor *ep;
 875         struct usb_cdc_dmm_desc *dmhd;
 876         u8 *buffer = intf->altsetting->extra;
 877         int buflen = intf->altsetting->extralen;
 878         u16 maxcom = WDM_DEFAULT_BUFSIZE;
 879
 880         if (!buffer)
 881                 goto err;
 882         while (buflen > 2) {
 883                 if (buffer[1] != USB_DT_CS_INTERFACE) {
 884                         dev_err(&intf->dev, "skipping garbage\n");
 885                         goto next_desc;
 886                 }
 887
 888                 switch (buffer[2]) {
 889                 case USB_CDC_HEADER_TYPE:
 890                         break;
 891                 case USB_CDC_DMM_TYPE:
 892                         dmhd = (struct usb_cdc_dmm_desc *)buffer;
 893                         maxcom = le16_to_cpu(dmhd->wMaxCommand);
 894                         dev_dbg(&intf->dev,
 895                                 "Finding maximum buffer length: %d", maxcom);
 896                         break;
 897                 default:
 898                         dev_err(&intf->dev,
 899                                 "Ignoring extra header, type %d, length %d\n",
 900                                 buffer[2], buffer[0]);
 901                         break;
 902                 }
 903 next_desc:
 904                 buflen -= buffer[0];
 905                 buffer += buffer[0];
 906         }
 907
 908         iface = intf->cur_altsetting;
 909         if (iface->desc.bNumEndpoints != 1)
 910                 goto err;
 911         ep = &iface->endpoint[0].desc;
 912
 913         rv = wdm_create(intf, ep, maxcom, &wdm_manage_power);
 914
 915 err:
 916         return rv;
 917 }
 918
 919 /**
 920  * usb_cdc_wdm_register - register a WDM subdriver
 921  * @intf: usb interface the subdriver will associate with
 922  * @ep: interrupt endpoint to monitor for notifications
 923  * @bufsize: maximum message size to support for read/write
 924  *
 925  * Create WDM usb class character device and associate it with intf
 926  * without binding, allowing another driver to manage the interface.
 927  *
 928  * The subdriver will manage the given interrupt endpoint exclusively
 929  * and will issue control requests referring to the given intf. It
 930  * will otherwise avoid interferring, and in particular not do
 931  * usb_set_intfdata/usb_get_intfdata on intf.
 932  *
 933  * The return value is a pointer to the subdriver's struct usb_driver.
 934  * The registering driver is responsible for calling this subdriver's
 935  * disconnect, suspend, resume, pre_reset and post_reset methods from
 936  * its own.
 937  */
 938 struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,
 939                                         struct usb_endpoint_descriptor *ep,
 940                                         int bufsize,
 941                                         int (*manage_power)(struct usb_interface *, int))
 942 {
 943         int rv = -EINVAL;
 944
 945         rv = wdm_create(intf, ep, bufsize, manage_power);
 946         if (rv < 0)
 947                 goto err;
 948
 949         return &wdm_driver;
 950 err:
 951         return ERR_PTR(rv);
 952 }
 953 EXPORT_SYMBOL(usb_cdc_wdm_register);
 954
 955 static void wdm_disconnect(struct usb_interface *intf)
 956 {
 957         struct wdm_device *desc;
 958         unsigned long flags;
 959
 960         usb_deregister_dev(intf, &wdm_class);
 961         desc = wdm_find_device(intf);
 962         mutex_lock(&wdm_mutex);
 963
 964         /* the spinlock makes sure no new urbs are generated in the callbacks */
 965         spin_lock_irqsave(&desc->iuspin, flags);
 966         set_bit(WDM_DISCONNECTING, &desc->flags);
 967         set_bit(WDM_READ, &desc->flags);
 968         /* to terminate pending flushes */
 969         clear_bit(WDM_IN_USE, &desc->flags);
 970         spin_unlock_irqrestore(&desc->iuspin, flags);
 971         wake_up_all(&desc->wait);
 972         mutex_lock(&desc->rlock);
 973         mutex_lock(&desc->wlock);
 974         kill_urbs(desc);
 975         cancel_work_sync(&desc->rxwork);
 976         mutex_unlock(&desc->wlock);
 977         mutex_unlock(&desc->rlock);
 978
 979         /* the desc->intf pointer used as list key is now invalid */
 980         spin_lock(&wdm_device_list_lock);
 981         list_del(&desc->device_list);
 982         spin_unlock(&wdm_device_list_lock);
 983
 984         if (!desc->count)
 985                 cleanup(desc);
 986         else
 987                 dev_dbg(&intf->dev, "%s: %d open files - postponing cleanup\n", __func__, desc->count);
 988         mutex_unlock(&wdm_mutex);
 989 }
 990
 991 #ifdef CONFIG_PM
 992 static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
 993 {
 994         struct wdm_device *desc = wdm_find_device(intf);
 995         int rv = 0;
 996
 997         dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
 998
 999         /* if this is an autosuspend the caller does the locking */
1000         if (!PMSG_IS_AUTO(message)) {
1001                 mutex_lock(&desc->rlock);
1002                 mutex_lock(&desc->wlock);
1003         }
1004         spin_lock_irq(&desc->iuspin);
1005
1006         if (PMSG_IS_AUTO(message) &&
1007                         (test_bit(WDM_IN_USE, &desc->flags)
1008                         || test_bit(WDM_RESPONDING, &desc->flags))) {
1009                 spin_unlock_irq(&desc->iuspin);
1010                 rv = -EBUSY;
1011         } else {
1012
1013                 set_bit(WDM_SUSPENDING, &desc->flags);
1014                 spin_unlock_irq(&desc->iuspin);
1015                 /* callback submits work - order is essential */
1016                 kill_urbs(desc);
1017                 cancel_work_sync(&desc->rxwork);
1018         }
1019         if (!PMSG_IS_AUTO(message)) {
1020                 mutex_unlock(&desc->wlock);
1021                 mutex_unlock(&desc->rlock);
1022         }
1023
1024         return rv;
1025 }
1026 #endif
1027
1028 static int recover_from_urb_loss(struct wdm_device *desc)
1029 {
1030         int rv = 0;
1031
1032         if (desc->count) {
1033                 rv = usb_submit_urb(desc->validity, GFP_NOIO);
1034                 if (rv < 0)
1035                         dev_err(&desc->intf->dev,
1036                                 "Error resume submitting int urb - %d\n", rv);
1037         }
1038         return rv;
1039 }
1040
1041 #ifdef CONFIG_PM
1042 static int wdm_resume(struct usb_interface *intf)
1043 {
1044         struct wdm_device *desc = wdm_find_device(intf);
1045         int rv;
1046
1047         dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
1048
1049         clear_bit(WDM_SUSPENDING, &desc->flags);
1050         rv = recover_from_urb_loss(desc);
1051
1052         return rv;
1053 }
1054 #endif
1055
1056 static int wdm_pre_reset(struct usb_interface *intf)
1057 {
1058         struct wdm_device *desc = wdm_find_device(intf);
1059
1060         /*
1061          * we notify everybody using poll of
1062          * an exceptional situation
1063          * must be done before recovery lest a spontaneous
1064          * message from the device is lost
1065          */
1066         spin_lock_irq(&desc->iuspin);
1067         set_bit(WDM_RESETTING, &desc->flags);   /* inform read/write */
1068         set_bit(WDM_READ, &desc->flags);        /* unblock read */
1069         clear_bit(WDM_IN_USE, &desc->flags);    /* unblock write */
1070         desc->rerr = -EINTR;
1071         spin_unlock_irq(&desc->iuspin);
1072         wake_up_all(&desc->wait);
1073         mutex_lock(&desc->rlock);
1074         mutex_lock(&desc->wlock);
1075         kill_urbs(desc);
1076         cancel_work_sync(&desc->rxwork);
1077         return 0;
1078 }
1079
1080 static int wdm_post_reset(struct usb_interface *intf)
1081 {
1082         struct wdm_device *desc = wdm_find_device(intf);
1083         int rv;
1084
1085         clear_bit(WDM_OVERFLOW, &desc->flags);
1086         clear_bit(WDM_RESETTING, &desc->flags);
1087         rv = recover_from_urb_loss(desc);
1088         mutex_unlock(&desc->wlock);
1089         mutex_unlock(&desc->rlock);
1090         return 0;
1091 }
1092
1093 static struct usb_driver wdm_driver = {
1094         .name =         "cdc_wdm",
1095         .probe =        wdm_probe,
1096         .disconnect =   wdm_disconnect,
1097 #ifdef CONFIG_PM
1098         .suspend =      wdm_suspend,
1099         .resume =       wdm_resume,
1100         .reset_resume = wdm_resume,
1101 #endif
1102         .pre_reset =    wdm_pre_reset,
1103         .post_reset =   wdm_post_reset,
1104         .id_table =     wdm_ids,
1105         .supports_autosuspend = 1,
1106         .disable_hub_initiated_lpm = 1,
1107 };
1108
1109 module_usb_driver(wdm_driver);
1110
1111 MODULE_AUTHOR(DRIVER_AUTHOR);
1112 MODULE_DESCRIPTION(DRIVER_DESC);
1113 MODULE_LICENSE("GPL");