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