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