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