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