drivers/usb/class/cdc-wdm.c

   1 /*
   2  * cdc-wdm.c
   3  *
   4  * This driver supports USB CDC WCM Device Management.
   5  *
   6  * Copyright (c) 2007-2009 Oliver Neukum
   7  *
   8  * Some code taken from cdc-acm.c
   9  *
  10  * Released under the GPLv2.
  11  *
  12  * Many thanks to Carl Nordbeck
  13  */
  14 #include <linux/kernel.h>
  15 #include <linux/errno.h>
  16 #include <linux/slab.h>
  17 #include <linux/module.h>
  18 #include <linux/mutex.h>
  19 #include <linux/uaccess.h>
  20 #include <linux/bitops.h>
  21 #include <linux/poll.h>
  22 #include <linux/usb.h>
  23 #include <linux/usb/cdc.h>
  24 #include <asm/byteorder.h>
  25 #include <asm/unaligned.h>
  26 #include <linux/usb/cdc-wdm.h>
  27
  28 /*
  29  * Version Information
  30  */
  31 #define DRIVER_VERSION "v0.03"
  32 #define DRIVER_AUTHOR "Oliver Neukum"
  33 #define DRIVER_DESC "USB Abstract Control Model driver for USB WCM Device Management"
  34
  35 static const struct usb_device_id wdm_ids[] = {
  36         {
  37                 .match_flags = USB_DEVICE_ID_MATCH_INT_CLASS |
  38                                  USB_DEVICE_ID_MATCH_INT_SUBCLASS,
  39                 .bInterfaceClass = USB_CLASS_COMM,
  40                 .bInterfaceSubClass = USB_CDC_SUBCLASS_DMM
  41         },
  42         { }
  43 };
  44
  45 MODULE_DEVICE_TABLE (usb, wdm_ids);
  46
  47 #define WDM_MINOR_BASE  176
  48
  49
  50 #define WDM_IN_USE              1
  51 #define WDM_DISCONNECTING       2
  52 #define WDM_RESULT              3
  53 #define WDM_READ                4
  54 #define WDM_INT_STALL           5
  55 #define WDM_POLL_RUNNING        6
  56 #define WDM_RESPONDING          7
  57 #define WDM_SUSPENDING          8
  58 #define WDM_RESETTING           9
  59
  60 #define WDM_MAX                 16
  61
  62 /* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */
  63 #define WDM_DEFAULT_BUFSIZE     256
  64
  65 static DEFINE_MUTEX(wdm_mutex);
  66 static DEFINE_SPINLOCK(wdm_device_list_lock);
  67 static LIST_HEAD(wdm_device_list);
  68
  69 /* --- method tables --- */
  70
  71 struct wdm_device {
  72         u8                      *inbuf; /* buffer for response */
  73         u8                      *outbuf; /* buffer for command */
  74         u8                      *sbuf; /* buffer for status */
  75         u8                      *ubuf; /* buffer for copy to user space */
  76
  77         struct urb              *command;
  78         struct urb              *response;
  79         struct urb              *validity;
  80         struct usb_interface    *intf;
  81         struct usb_ctrlrequest  *orq;
  82         struct usb_ctrlrequest  *irq;
  83         spinlock_t              iuspin;
  84
  85         unsigned long           flags;
  86         u16                     bufsize;
  87         u16                     wMaxCommand;
  88         u16                     wMaxPacketSize;
  89         __le16                  inum;
  90         int                     reslength;
  91         int                     length;
  92         int                     read;
  93         int                     count;
  94         dma_addr_t              shandle;
  95         dma_addr_t              ihandle;
  96         struct mutex            wlock;
  97         struct mutex            rlock;
  98         wait_queue_head_t       wait;
  99         struct work_struct      rxwork;
 100         int                     werr;
 101         int                     rerr;
 102
 103         struct list_head        device_list;
 104         int                     (*manage_power)(struct usb_interface *, int);
 105 };
 106
 107 static struct usb_driver wdm_driver;
 108
 109 /* return intfdata if we own the interface, else look up intf in the list */
 110 static struct wdm_device *wdm_find_device(struct usb_interface *intf)
 111 {
 112         struct wdm_device *desc = NULL;
 113
 114         spin_lock(&wdm_device_list_lock);
 115         list_for_each_entry(desc, &wdm_device_list, device_list)
 116                 if (desc->intf == intf)
 117                         break;
 118         spin_unlock(&wdm_device_list_lock);
 119
 120         return desc;
 121 }
 122
 123 static struct wdm_device *wdm_find_device_by_minor(int minor)
 124 {
 125         struct wdm_device *desc = NULL;
 126
 127         spin_lock(&wdm_device_list_lock);
 128         list_for_each_entry(desc, &wdm_device_list, device_list)
 129                 if (desc->intf->minor == minor)
 130                         break;
 131         spin_unlock(&wdm_device_list_lock);
 132
 133         return desc;
 134 }
 135
 136 /* --- callbacks --- */
 137 static void wdm_out_callback(struct urb *urb)
 138 {
 139         struct wdm_device *desc;
 140         desc = urb->context;
 141         spin_lock(&desc->iuspin);
 142         desc->werr = urb->status;
 143         spin_unlock(&desc->iuspin);
 144         kfree(desc->outbuf);
 145         desc->outbuf = NULL;
 146         clear_bit(WDM_IN_USE, &desc->flags);
 147         wake_up(&desc->wait);
 148 }
 149
 150 static void wdm_in_callback(struct urb *urb)
 151 {
 152         struct wdm_device *desc = urb->context;
 153         int status = urb->status;
 154
 155         spin_lock(&desc->iuspin);
 156         clear_bit(WDM_RESPONDING, &desc->flags);
 157
 158         if (status) {
 159                 switch (status) {
 160                 case -ENOENT:
 161                         dev_dbg(&desc->intf->dev,
 162                                 "nonzero urb status received: -ENOENT");
 163                         goto skip_error;
 164                 case -ECONNRESET:
 165                         dev_dbg(&desc->intf->dev,
 166                                 "nonzero urb status received: -ECONNRESET");
 167                         goto skip_error;
 168                 case -ESHUTDOWN:
 169                         dev_dbg(&desc->intf->dev,
 170                                 "nonzero urb status received: -ESHUTDOWN");
 171                         goto skip_error;
 172                 case -EPIPE:
 173                         dev_err(&desc->intf->dev,
 174                                 "nonzero urb status received: -EPIPE\n");
 175                         break;
 176                 default:
 177                         dev_err(&desc->intf->dev,
 178                                 "Unexpected error %d\n", status);
 179                         break;
 180                 }
 181         }
 182
 183         desc->rerr = status;
 184         desc->reslength = urb->actual_length;
 185         memmove(desc->ubuf + desc->length, desc->inbuf, desc->reslength);
 186         desc->length += desc->reslength;
 187 skip_error:
 188         wake_up(&desc->wait);
 189
 190         set_bit(WDM_READ, &desc->flags);
 191         spin_unlock(&desc->iuspin);
 192 }
 193
 194 static void wdm_int_callback(struct urb *urb)
 195 {
 196         int rv = 0;
 197         int status = urb->status;
 198         struct wdm_device *desc;
 199         struct usb_cdc_notification *dr;
 200
 201         desc = urb->context;
 202         dr = (struct usb_cdc_notification *)desc->sbuf;
 203
 204         if (status) {
 205                 switch (status) {
 206                 case -ESHUTDOWN:
 207                 case -ENOENT:
 208                 case -ECONNRESET:
 209                         return; /* unplug */
 210                 case -EPIPE:
 211                         set_bit(WDM_INT_STALL, &desc->flags);
 212                         dev_err(&desc->intf->dev, "Stall on int endpoint\n");
 213                         goto sw; /* halt is cleared in work */
 214                 default:
 215                         dev_err(&desc->intf->dev,
 216                                 "nonzero urb status received: %d\n", status);
 217                         break;
 218                 }
 219         }
 220
 221         if (urb->actual_length < sizeof(struct usb_cdc_notification)) {
 222                 dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n",
 223                         urb->actual_length);
 224                 goto exit;
 225         }
 226
 227         switch (dr->bNotificationType) {
 228         case USB_CDC_NOTIFY_RESPONSE_AVAILABLE:
 229                 dev_dbg(&desc->intf->dev,
 230                         "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d",
 231                         dr->wIndex, dr->wLength);
 232                 break;
 233
 234         case USB_CDC_NOTIFY_NETWORK_CONNECTION:
 235
 236                 dev_dbg(&desc->intf->dev,
 237                         "NOTIFY_NETWORK_CONNECTION %s network",
 238                         dr->wValue ? "connected to" : "disconnected from");
 239                 goto exit;
 240         default:
 241                 clear_bit(WDM_POLL_RUNNING, &desc->flags);
 242                 dev_err(&desc->intf->dev,
 243                         "unknown notification %d received: index %d len %d\n",
 244                         dr->bNotificationType, dr->wIndex, dr->wLength);
 245                 goto exit;
 246         }
 247
 248         spin_lock(&desc->iuspin);
 249         clear_bit(WDM_READ, &desc->flags);
 250         set_bit(WDM_RESPONDING, &desc->flags);
 251         if (!test_bit(WDM_DISCONNECTING, &desc->flags)
 252                 && !test_bit(WDM_SUSPENDING, &desc->flags)) {
 253                 rv = usb_submit_urb(desc->response, GFP_ATOMIC);
 254                 dev_dbg(&desc->intf->dev, "%s: usb_submit_urb %d",
 255                         __func__, rv);
 256         }
 257         spin_unlock(&desc->iuspin);
 258         if (rv < 0) {
 259                 clear_bit(WDM_RESPONDING, &desc->flags);
 260                 if (rv == -EPERM)
 261                         return;
 262                 if (rv == -ENOMEM) {
 263 sw:
 264                         rv = schedule_work(&desc->rxwork);
 265                         if (rv)
 266                                 dev_err(&desc->intf->dev,
 267                                         "Cannot schedule work\n");
 268                 }
 269         }
 270 exit:
 271         rv = usb_submit_urb(urb, GFP_ATOMIC);
 272         if (rv)
 273                 dev_err(&desc->intf->dev,
 274                         "%s - usb_submit_urb failed with result %d\n",
 275                         __func__, rv);
 276
 277 }
 278
 279 static void kill_urbs(struct wdm_device *desc)
 280 {
 281         /* the order here is essential */
 282         usb_kill_urb(desc->command);
 283         usb_kill_urb(desc->validity);
 284         usb_kill_urb(desc->response);
 285 }
 286
 287 static void free_urbs(struct wdm_device *desc)
 288 {
 289         usb_free_urb(desc->validity);
 290         usb_free_urb(desc->response);
 291         usb_free_urb(desc->command);
 292 }
 293
 294 static void cleanup(struct wdm_device *desc)
 295 {
 296         kfree(desc->sbuf);
 297         kfree(desc->inbuf);
 298         kfree(desc->orq);
 299         kfree(desc->irq);
 300         kfree(desc->ubuf);
 301         free_urbs(desc);
 302         kfree(desc);
 303 }
 304
 305 static ssize_t wdm_write
 306 (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 307 {
 308         u8 *buf;
 309         int rv = -EMSGSIZE, r, we;
 310         struct wdm_device *desc = file->private_data;
 311         struct usb_ctrlrequest *req;
 312
 313         if (count > desc->wMaxCommand)
 314                 count = desc->wMaxCommand;
 315
 316         spin_lock_irq(&desc->iuspin);
 317         we = desc->werr;
 318         desc->werr = 0;
 319         spin_unlock_irq(&desc->iuspin);
 320         if (we < 0)
 321                 return -EIO;
 322
 323         buf = kmalloc(count, GFP_KERNEL);
 324         if (!buf) {
 325                 rv = -ENOMEM;
 326                 goto outnl;
 327         }
 328
 329         r = copy_from_user(buf, buffer, count);
 330         if (r > 0) {
 331                 kfree(buf);
 332                 rv = -EFAULT;
 333                 goto outnl;
 334         }
 335
 336         /* concurrent writes and disconnect */
 337         r = mutex_lock_interruptible(&desc->wlock);
 338         rv = -ERESTARTSYS;
 339         if (r) {
 340                 kfree(buf);
 341                 goto outnl;
 342         }
 343
 344         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 345                 kfree(buf);
 346                 rv = -ENODEV;
 347                 goto outnp;
 348         }
 349
 350         r = usb_autopm_get_interface(desc->intf);
 351         if (r < 0) {
 352                 kfree(buf);
 353                 rv = usb_translate_errors(r);
 354                 goto outnp;
 355         }
 356
 357         if (!(file->f_flags & O_NONBLOCK))
 358                 r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
 359                                                                 &desc->flags));
 360         else
 361                 if (test_bit(WDM_IN_USE, &desc->flags))
 362                         r = -EAGAIN;
 363
 364         if (test_bit(WDM_RESETTING, &desc->flags))
 365                 r = -EIO;
 366
 367         if (r < 0) {
 368                 kfree(buf);
 369                 rv = r;
 370                 goto out;
 371         }
 372
 373         req = desc->orq;
 374         usb_fill_control_urb(
 375                 desc->command,
 376                 interface_to_usbdev(desc->intf),
 377                 /* using common endpoint 0 */
 378                 usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
 379                 (unsigned char *)req,
 380                 buf,
 381                 count,
 382                 wdm_out_callback,
 383                 desc
 384         );
 385
 386         req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
 387                              USB_RECIP_INTERFACE);
 388         req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
 389         req->wValue = 0;
 390         req->wIndex = desc->inum;
 391         req->wLength = cpu_to_le16(count);
 392         set_bit(WDM_IN_USE, &desc->flags);
 393         desc->outbuf = buf;
 394
 395         rv = usb_submit_urb(desc->command, GFP_KERNEL);
 396         if (rv < 0) {
 397                 kfree(buf);
 398                 desc->outbuf = NULL;
 399                 clear_bit(WDM_IN_USE, &desc->flags);
 400                 dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
 401                 rv = usb_translate_errors(rv);
 402         } else {
 403                 dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d",
 404                         req->wIndex);
 405         }
 406 out:
 407         usb_autopm_put_interface(desc->intf);
 408 outnp:
 409         mutex_unlock(&desc->wlock);
 410 outnl:
 411         return rv < 0 ? rv : count;
 412 }
 413
 414 static ssize_t wdm_read
 415 (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 416 {
 417         int rv, cntr;
 418         int i = 0;
 419         struct wdm_device *desc = file->private_data;
 420
 421
 422         rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
 423         if (rv < 0)
 424                 return -ERESTARTSYS;
 425
 426         cntr = ACCESS_ONCE(desc->length);
 427         if (cntr == 0) {
 428                 desc->read = 0;
 429 retry:
 430                 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 431                         rv = -ENODEV;
 432                         goto err;
 433                 }
 434                 i++;
 435                 if (file->f_flags & O_NONBLOCK) {
 436                         if (!test_bit(WDM_READ, &desc->flags)) {
 437                                 rv = cntr ? cntr : -EAGAIN;
 438                                 goto err;
 439                         }
 440                         rv = 0;
 441                 } else {
 442                         rv = wait_event_interruptible(desc->wait,
 443                                 test_bit(WDM_READ, &desc->flags));
 444                 }
 445
 446                 /* may have happened while we slept */
 447                 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 448                         rv = -ENODEV;
 449                         goto err;
 450                 }
 451                 if (test_bit(WDM_RESETTING, &desc->flags)) {
 452                         rv = -EIO;
 453                         goto err;
 454                 }
 455                 usb_mark_last_busy(interface_to_usbdev(desc->intf));
 456                 if (rv < 0) {
 457                         rv = -ERESTARTSYS;
 458                         goto err;
 459                 }
 460
 461                 spin_lock_irq(&desc->iuspin);
 462
 463                 if (desc->rerr) { /* read completed, error happened */
 464                         desc->rerr = 0;
 465                         spin_unlock_irq(&desc->iuspin);
 466                         rv = -EIO;
 467                         goto err;
 468                 }
 469                 /*
 470                  * recheck whether we've lost the race
 471                  * against the completion handler
 472                  */
 473                 if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */
 474                         spin_unlock_irq(&desc->iuspin);
 475                         goto retry;
 476                 }
 477                 if (!desc->reslength) { /* zero length read */
 478                         dev_dbg(&desc->intf->dev, "%s: zero length - clearing WDM_READ\n", __func__);
 479                         clear_bit(WDM_READ, &desc->flags);
 480                         spin_unlock_irq(&desc->iuspin);
 481                         goto retry;
 482                 }
 483                 cntr = desc->length;
 484                 spin_unlock_irq(&desc->iuspin);
 485         }
 486
 487         if (cntr > count)
 488                 cntr = count;
 489         rv = copy_to_user(buffer, desc->ubuf, cntr);
 490         if (rv > 0) {
 491                 rv = -EFAULT;
 492                 goto err;
 493         }
 494
 495         spin_lock_irq(&desc->iuspin);
 496
 497         for (i = 0; i < desc->length - cntr; i++)
 498                 desc->ubuf[i] = desc->ubuf[i + cntr];
 499
 500         desc->length -= cntr;
 501         /* in case we had outstanding data */
 502         if (!desc->length)
 503                 clear_bit(WDM_READ, &desc->flags);
 504
 505         spin_unlock_irq(&desc->iuspin);
 506
 507         rv = cntr;
 508
 509 err:
 510         mutex_unlock(&desc->rlock);
 511         return rv;
 512 }
 513
 514 static int wdm_flush(struct file *file, fl_owner_t id)
 515 {
 516         struct wdm_device *desc = file->private_data;
 517
 518         wait_event(desc->wait, !test_bit(WDM_IN_USE, &desc->flags));
 519
 520         /* cannot dereference desc->intf if WDM_DISCONNECTING */
 521         if (desc->werr < 0 && !test_bit(WDM_DISCONNECTING, &desc->flags))
 522                 dev_err(&desc->intf->dev, "Error in flush path: %d\n",
 523                         desc->werr);
 524
 525         return usb_translate_errors(desc->werr);
 526 }
 527
 528 static unsigned int wdm_poll(struct file *file, struct poll_table_struct *wait)
 529 {
 530         struct wdm_device *desc = file->private_data;
 531         unsigned long flags;
 532         unsigned int mask = 0;
 533
 534         spin_lock_irqsave(&desc->iuspin, flags);
 535         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 536                 mask = POLLHUP | POLLERR;
 537                 spin_unlock_irqrestore(&desc->iuspin, flags);
 538                 goto desc_out;
 539         }
 540         if (test_bit(WDM_READ, &desc->flags))
 541                 mask = POLLIN | POLLRDNORM;
 542         if (desc->rerr || desc->werr)
 543                 mask |= POLLERR;
 544         if (!test_bit(WDM_IN_USE, &desc->flags))
 545                 mask |= POLLOUT | POLLWRNORM;
 546         spin_unlock_irqrestore(&desc->iuspin, flags);
 547
 548         poll_wait(file, &desc->wait, wait);
 549
 550 desc_out:
 551         return mask;
 552 }
 553
 554 static int wdm_open(struct inode *inode, struct file *file)
 555 {
 556         int minor = iminor(inode);
 557         int rv = -ENODEV;
 558         struct usb_interface *intf;
 559         struct wdm_device *desc;
 560
 561         mutex_lock(&wdm_mutex);
 562         desc = wdm_find_device_by_minor(minor);
 563         if (!desc)
 564                 goto out;
 565
 566         intf = desc->intf;
 567         if (test_bit(WDM_DISCONNECTING, &desc->flags))
 568                 goto out;
 569         file->private_data = desc;
 570
 571         rv = usb_autopm_get_interface(desc->intf);
 572         if (rv < 0) {
 573                 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
 574                 goto out;
 575         }
 576
 577         /* using write lock to protect desc->count */
 578         mutex_lock(&desc->wlock);
 579         if (!desc->count++) {
 580                 desc->werr = 0;
 581                 desc->rerr = 0;
 582                 rv = usb_submit_urb(desc->validity, GFP_KERNEL);
 583                 if (rv < 0) {
 584                         desc->count--;
 585                         dev_err(&desc->intf->dev,
 586                                 "Error submitting int urb - %d\n", rv);
 587                         rv = usb_translate_errors(rv);
 588                 }
 589         } else {
 590                 rv = 0;
 591         }
 592         mutex_unlock(&desc->wlock);
 593         if (desc->count == 1)
 594                 desc->manage_power(intf, 1);
 595         usb_autopm_put_interface(desc->intf);
 596 out:
 597         mutex_unlock(&wdm_mutex);
 598         return rv;
 599 }
 600
 601 static int wdm_release(struct inode *inode, struct file *file)
 602 {
 603         struct wdm_device *desc = file->private_data;
 604
 605         mutex_lock(&wdm_mutex);
 606
 607         /* using write lock to protect desc->count */
 608         mutex_lock(&desc->wlock);
 609         desc->count--;
 610         mutex_unlock(&desc->wlock);
 611
 612         if (!desc->count) {
 613                 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
 614                         dev_dbg(&desc->intf->dev, "wdm_release: cleanup");
 615                         kill_urbs(desc);
 616                         desc->manage_power(desc->intf, 0);
 617                 } else {
 618                         /* must avoid dev_printk here as desc->intf is invalid */
 619                         pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
 620                         cleanup(desc);
 621                 }
 622         }
 623         mutex_unlock(&wdm_mutex);
 624         return 0;
 625 }
 626
 627 static const struct file_operations wdm_fops = {
 628         .owner =        THIS_MODULE,
 629         .read =         wdm_read,
 630         .write =        wdm_write,
 631         .open =         wdm_open,
 632         .flush =        wdm_flush,
 633         .release =      wdm_release,
 634         .poll =         wdm_poll,
 635         .llseek =       noop_llseek,
 636 };
 637
 638 static struct usb_class_driver wdm_class = {
 639         .name =         "cdc-wdm%d",
 640         .fops =         &wdm_fops,
 641         .minor_base =   WDM_MINOR_BASE,
 642 };
 643
 644 /* --- error handling --- */
 645 static void wdm_rxwork(struct work_struct *work)
 646 {
 647         struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
 648         unsigned long flags;
 649         int rv;
 650
 651         spin_lock_irqsave(&desc->iuspin, flags);
 652         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 653                 spin_unlock_irqrestore(&desc->iuspin, flags);
 654         } else {
 655                 spin_unlock_irqrestore(&desc->iuspin, flags);
 656                 rv = usb_submit_urb(desc->response, GFP_KERNEL);
 657                 if (rv < 0 && rv != -EPERM) {
 658                         spin_lock_irqsave(&desc->iuspin, flags);
 659                         if (!test_bit(WDM_DISCONNECTING, &desc->flags))
 660                                 schedule_work(&desc->rxwork);
 661                         spin_unlock_irqrestore(&desc->iuspin, flags);
 662                 }
 663         }
 664 }
 665
 666 /* --- hotplug --- */
 667
 668 static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
 669                 u16 bufsize, int (*manage_power)(struct usb_interface *, int))
 670 {
 671         int rv = -ENOMEM;
 672         struct wdm_device *desc;
 673
 674         desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
 675         if (!desc)
 676                 goto out;
 677         INIT_LIST_HEAD(&desc->device_list);
 678         mutex_init(&desc->rlock);
 679         mutex_init(&desc->wlock);
 680         spin_lock_init(&desc->iuspin);
 681         init_waitqueue_head(&desc->wait);
 682         desc->wMaxCommand = bufsize;
 683         /* this will be expanded and needed in hardware endianness */
 684         desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
 685         desc->intf = intf;
 686         INIT_WORK(&desc->rxwork, wdm_rxwork);
 687
 688         rv = -EINVAL;
 689         if (!usb_endpoint_is_int_in(ep))
 690                 goto err;
 691
 692         desc->wMaxPacketSize = usb_endpoint_maxp(ep);
 693
 694         desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
 695         if (!desc->orq)
 696                 goto err;
 697         desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
 698         if (!desc->irq)
 699                 goto err;
 700
 701         desc->validity = usb_alloc_urb(0, GFP_KERNEL);
 702         if (!desc->validity)
 703                 goto err;
 704
 705         desc->response = usb_alloc_urb(0, GFP_KERNEL);
 706         if (!desc->response)
 707                 goto err;
 708
 709         desc->command = usb_alloc_urb(0, GFP_KERNEL);
 710         if (!desc->command)
 711                 goto err;
 712
 713         desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
 714         if (!desc->ubuf)
 715                 goto err;
 716
 717         desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);
 718         if (!desc->sbuf)
 719                 goto err;
 720
 721         desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
 722         if (!desc->inbuf)
 723                 goto err;
 724
 725         usb_fill_int_urb(
 726                 desc->validity,
 727                 interface_to_usbdev(intf),
 728                 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
 729                 desc->sbuf,
 730                 desc->wMaxPacketSize,
 731                 wdm_int_callback,
 732                 desc,
 733                 ep->bInterval
 734         );
 735
 736         desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
 737         desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
 738         desc->irq->wValue = 0;
 739         desc->irq->wIndex = desc->inum;
 740         desc->irq->wLength = cpu_to_le16(desc->wMaxCommand);
 741
 742         usb_fill_control_urb(
 743                 desc->response,
 744                 interface_to_usbdev(intf),
 745                 /* using common endpoint 0 */
 746                 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
 747                 (unsigned char *)desc->irq,
 748                 desc->inbuf,
 749                 desc->wMaxCommand,
 750                 wdm_in_callback,
 751                 desc
 752         );
 753
 754         desc->manage_power = manage_power;
 755
 756         spin_lock(&wdm_device_list_lock);
 757         list_add(&desc->device_list, &wdm_device_list);
 758         spin_unlock(&wdm_device_list_lock);
 759
 760         rv = usb_register_dev(intf, &wdm_class);
 761         if (rv < 0)
 762                 goto err;
 763         else
 764                 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev));
 765 out:
 766         return rv;
 767 err:
 768         spin_lock(&wdm_device_list_lock);
 769         list_del(&desc->device_list);
 770         spin_unlock(&wdm_device_list_lock);
 771         cleanup(desc);
 772         return rv;
 773 }
 774
 775 static int wdm_manage_power(struct usb_interface *intf, int on)
 776 {
 777         /* need autopm_get/put here to ensure the usbcore sees the new value */
 778         int rv = usb_autopm_get_interface(intf);
 779         if (rv < 0)
 780                 goto err;
 781
 782         intf->needs_remote_wakeup = on;
 783         usb_autopm_put_interface(intf);
 784 err:
 785         return rv;
 786 }
 787
 788 static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
 789 {
 790         int rv = -EINVAL;
 791         struct usb_host_interface *iface;
 792         struct usb_endpoint_descriptor *ep;
 793         struct usb_cdc_dmm_desc *dmhd;
 794         u8 *buffer = intf->altsetting->extra;
 795         int buflen = intf->altsetting->extralen;
 796         u16 maxcom = WDM_DEFAULT_BUFSIZE;
 797
 798         if (!buffer)
 799                 goto err;
 800         while (buflen > 2) {
 801                 if (buffer[1] != USB_DT_CS_INTERFACE) {
 802                         dev_err(&intf->dev, "skipping garbage\n");
 803                         goto next_desc;
 804                 }
 805
 806                 switch (buffer[2]) {
 807                 case USB_CDC_HEADER_TYPE:
 808                         break;
 809                 case USB_CDC_DMM_TYPE:
 810                         dmhd = (struct usb_cdc_dmm_desc *)buffer;
 811                         maxcom = le16_to_cpu(dmhd->wMaxCommand);
 812                         dev_dbg(&intf->dev,
 813                                 "Finding maximum buffer length: %d", maxcom);
 814                         break;
 815                 default:
 816                         dev_err(&intf->dev,
 817                                 "Ignoring extra header, type %d, length %d\n",
 818                                 buffer[2], buffer[0]);
 819                         break;
 820                 }
 821 next_desc:
 822                 buflen -= buffer[0];
 823                 buffer += buffer[0];
 824         }
 825
 826         iface = intf->cur_altsetting;
 827         if (iface->desc.bNumEndpoints != 1)
 828                 goto err;
 829         ep = &iface->endpoint[0].desc;
 830
 831         rv = wdm_create(intf, ep, maxcom, &wdm_manage_power);
 832
 833 err:
 834         return rv;
 835 }
 836
 837 /**
 838  * usb_cdc_wdm_register - register a WDM subdriver
 839  * @intf: usb interface the subdriver will associate with
 840  * @ep: interrupt endpoint to monitor for notifications
 841  * @bufsize: maximum message size to support for read/write
 842  *
 843  * Create WDM usb class character device and associate it with intf
 844  * without binding, allowing another driver to manage the interface.
 845  *
 846  * The subdriver will manage the given interrupt endpoint exclusively
 847  * and will issue control requests referring to the given intf. It
 848  * will otherwise avoid interferring, and in particular not do
 849  * usb_set_intfdata/usb_get_intfdata on intf.
 850  *
 851  * The return value is a pointer to the subdriver's struct usb_driver.
 852  * The registering driver is responsible for calling this subdriver's
 853  * disconnect, suspend, resume, pre_reset and post_reset methods from
 854  * its own.
 855  */
 856 struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,
 857                                         struct usb_endpoint_descriptor *ep,
 858                                         int bufsize,
 859                                         int (*manage_power)(struct usb_interface *, int))
 860 {
 861         int rv = -EINVAL;
 862
 863         rv = wdm_create(intf, ep, bufsize, manage_power);
 864         if (rv < 0)
 865                 goto err;
 866
 867         return &wdm_driver;
 868 err:
 869         return ERR_PTR(rv);
 870 }
 871 EXPORT_SYMBOL(usb_cdc_wdm_register);
 872
 873 static void wdm_disconnect(struct usb_interface *intf)
 874 {
 875         struct wdm_device *desc;
 876         unsigned long flags;
 877
 878         usb_deregister_dev(intf, &wdm_class);
 879         desc = wdm_find_device(intf);
 880         mutex_lock(&wdm_mutex);
 881
 882         /* the spinlock makes sure no new urbs are generated in the callbacks */
 883         spin_lock_irqsave(&desc->iuspin, flags);
 884         set_bit(WDM_DISCONNECTING, &desc->flags);
 885         set_bit(WDM_READ, &desc->flags);
 886         /* to terminate pending flushes */
 887         clear_bit(WDM_IN_USE, &desc->flags);
 888         spin_unlock_irqrestore(&desc->iuspin, flags);
 889         wake_up_all(&desc->wait);
 890         mutex_lock(&desc->rlock);
 891         mutex_lock(&desc->wlock);
 892         kill_urbs(desc);
 893         cancel_work_sync(&desc->rxwork);
 894         mutex_unlock(&desc->wlock);
 895         mutex_unlock(&desc->rlock);
 896
 897         /* the desc->intf pointer used as list key is now invalid */
 898         spin_lock(&wdm_device_list_lock);
 899         list_del(&desc->device_list);
 900         spin_unlock(&wdm_device_list_lock);
 901
 902         if (!desc->count)
 903                 cleanup(desc);
 904         else
 905                 dev_dbg(&intf->dev, "%s: %d open files - postponing cleanup\n", __func__, desc->count);
 906         mutex_unlock(&wdm_mutex);
 907 }
 908
 909 #ifdef CONFIG_PM
 910 static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
 911 {
 912         struct wdm_device *desc = wdm_find_device(intf);
 913         int rv = 0;
 914
 915         dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
 916
 917         /* if this is an autosuspend the caller does the locking */
 918         if (!PMSG_IS_AUTO(message)) {
 919                 mutex_lock(&desc->rlock);
 920                 mutex_lock(&desc->wlock);
 921         }
 922         spin_lock_irq(&desc->iuspin);
 923
 924         if (PMSG_IS_AUTO(message) &&
 925                         (test_bit(WDM_IN_USE, &desc->flags)
 926                         || test_bit(WDM_RESPONDING, &desc->flags))) {
 927                 spin_unlock_irq(&desc->iuspin);
 928                 rv = -EBUSY;
 929         } else {
 930
 931                 set_bit(WDM_SUSPENDING, &desc->flags);
 932                 spin_unlock_irq(&desc->iuspin);
 933                 /* callback submits work - order is essential */
 934                 kill_urbs(desc);
 935                 cancel_work_sync(&desc->rxwork);
 936         }
 937         if (!PMSG_IS_AUTO(message)) {
 938                 mutex_unlock(&desc->wlock);
 939                 mutex_unlock(&desc->rlock);
 940         }
 941
 942         return rv;
 943 }
 944 #endif
 945
 946 static int recover_from_urb_loss(struct wdm_device *desc)
 947 {
 948         int rv = 0;
 949
 950         if (desc->count) {
 951                 rv = usb_submit_urb(desc->validity, GFP_NOIO);
 952                 if (rv < 0)
 953                         dev_err(&desc->intf->dev,
 954                                 "Error resume submitting int urb - %d\n", rv);
 955         }
 956         return rv;
 957 }
 958
 959 #ifdef CONFIG_PM
 960 static int wdm_resume(struct usb_interface *intf)
 961 {
 962         struct wdm_device *desc = wdm_find_device(intf);
 963         int rv;
 964
 965         dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
 966
 967         clear_bit(WDM_SUSPENDING, &desc->flags);
 968         rv = recover_from_urb_loss(desc);
 969
 970         return rv;
 971 }
 972 #endif
 973
 974 static int wdm_pre_reset(struct usb_interface *intf)
 975 {
 976         struct wdm_device *desc = wdm_find_device(intf);
 977
 978         /*
 979          * we notify everybody using poll of
 980          * an exceptional situation
 981          * must be done before recovery lest a spontaneous
 982          * message from the device is lost
 983          */
 984         spin_lock_irq(&desc->iuspin);
 985         set_bit(WDM_RESETTING, &desc->flags);   /* inform read/write */
 986         set_bit(WDM_READ, &desc->flags);        /* unblock read */
 987         clear_bit(WDM_IN_USE, &desc->flags);    /* unblock write */
 988         desc->rerr = -EINTR;
 989         spin_unlock_irq(&desc->iuspin);
 990         wake_up_all(&desc->wait);
 991         mutex_lock(&desc->rlock);
 992         mutex_lock(&desc->wlock);
 993         kill_urbs(desc);
 994         cancel_work_sync(&desc->rxwork);
 995         return 0;
 996 }
 997
 998 static int wdm_post_reset(struct usb_interface *intf)
 999 {
1000         struct wdm_device *desc = wdm_find_device(intf);
1001         int rv;
1002
1003         clear_bit(WDM_RESETTING, &desc->flags);
1004         rv = recover_from_urb_loss(desc);
1005         mutex_unlock(&desc->wlock);
1006         mutex_unlock(&desc->rlock);
1007         return 0;
1008 }
1009
1010 static struct usb_driver wdm_driver = {
1011         .name =         "cdc_wdm",
1012         .probe =        wdm_probe,
1013         .disconnect =   wdm_disconnect,
1014 #ifdef CONFIG_PM
1015         .suspend =      wdm_suspend,
1016         .resume =       wdm_resume,
1017         .reset_resume = wdm_resume,
1018 #endif
1019         .pre_reset =    wdm_pre_reset,
1020         .post_reset =   wdm_post_reset,
1021         .id_table =     wdm_ids,
1022         .supports_autosuspend = 1,
1023         .disable_hub_initiated_lpm = 1,
1024 };
1025
1026 module_usb_driver(wdm_driver);
1027
1028 MODULE_AUTHOR(DRIVER_AUTHOR);
1029 MODULE_DESCRIPTION(DRIVER_DESC);
1030 MODULE_LICENSE("GPL");