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 #define HUAWEI_VENDOR_ID        0x12D1
  36
  37 static const struct usb_device_id wdm_ids[] = {
  38         {
  39                 .match_flags = USB_DEVICE_ID_MATCH_INT_CLASS |
  40                                  USB_DEVICE_ID_MATCH_INT_SUBCLASS,
  41                 .bInterfaceClass = USB_CLASS_COMM,
  42                 .bInterfaceSubClass = USB_CDC_SUBCLASS_DMM
  43         },
  44         {
  45                 /*
  46                  * Huawei E392, E398 and possibly other Qualcomm based modems
  47                  * embed the Qualcomm QMI protocol inside CDC on CDC ECM like
  48                  * control interfaces.  Userspace access to this is required
  49                  * to configure the accompanying data interface
  50                  */
  51                 .match_flags        = USB_DEVICE_ID_MATCH_VENDOR |
  52                                         USB_DEVICE_ID_MATCH_INT_INFO,
  53                 .idVendor           = HUAWEI_VENDOR_ID,
  54                 .bInterfaceClass    = USB_CLASS_VENDOR_SPEC,
  55                 .bInterfaceSubClass = 1,
  56                 .bInterfaceProtocol = 9, /* NOTE: CDC ECM control interface! */
  57         },
  58         {
  59                  /* Vodafone/Huawei K5005 (12d1:14c8) and similar modems */
  60                 .match_flags        = USB_DEVICE_ID_MATCH_VENDOR |
  61                                       USB_DEVICE_ID_MATCH_INT_INFO,
  62                 .idVendor           = HUAWEI_VENDOR_ID,
  63                 .bInterfaceClass    = USB_CLASS_VENDOR_SPEC,
  64                 .bInterfaceSubClass = 1,
  65                 .bInterfaceProtocol = 57, /* NOTE: CDC ECM control interface! */
  66         },
  67         { }
  68 };
  69
  70 MODULE_DEVICE_TABLE (usb, wdm_ids);
  71
  72 #define WDM_MINOR_BASE  176
  73
  74
  75 #define WDM_IN_USE              1
  76 #define WDM_DISCONNECTING       2
  77 #define WDM_RESULT              3
  78 #define WDM_READ                4
  79 #define WDM_INT_STALL           5
  80 #define WDM_POLL_RUNNING        6
  81 #define WDM_RESPONDING          7
  82 #define WDM_SUSPENDING          8
  83 #define WDM_RESETTING           9
  84
  85 #define WDM_MAX                 16
  86
  87 /* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */
  88 #define WDM_DEFAULT_BUFSIZE     256
  89
  90 static DEFINE_MUTEX(wdm_mutex);
  91 static DEFINE_SPINLOCK(wdm_device_list_lock);
  92 static LIST_HEAD(wdm_device_list);
  93
  94 /* --- method tables --- */
  95
  96 struct wdm_device {
  97         u8                      *inbuf; /* buffer for response */
  98         u8                      *outbuf; /* buffer for command */
  99         u8                      *sbuf; /* buffer for status */
 100         u8                      *ubuf; /* buffer for copy to user space */
 101
 102         struct urb              *command;
 103         struct urb              *response;
 104         struct urb              *validity;
 105         struct usb_interface    *intf;
 106         struct usb_ctrlrequest  *orq;
 107         struct usb_ctrlrequest  *irq;
 108         spinlock_t              iuspin;
 109
 110         unsigned long           flags;
 111         u16                     bufsize;
 112         u16                     wMaxCommand;
 113         u16                     wMaxPacketSize;
 114         __le16                  inum;
 115         int                     reslength;
 116         int                     length;
 117         int                     read;
 118         int                     count;
 119         dma_addr_t              shandle;
 120         dma_addr_t              ihandle;
 121         struct mutex            wlock;
 122         struct mutex            rlock;
 123         wait_queue_head_t       wait;
 124         struct work_struct      rxwork;
 125         int                     werr;
 126         int                     rerr;
 127
 128         struct list_head        device_list;
 129         int                     (*manage_power)(struct usb_interface *, int);
 130 };
 131
 132 static struct usb_driver wdm_driver;
 133
 134 /* return intfdata if we own the interface, else look up intf in the list */
 135 static struct wdm_device *wdm_find_device(struct usb_interface *intf)
 136 {
 137         struct wdm_device *desc = NULL;
 138
 139         spin_lock(&wdm_device_list_lock);
 140         list_for_each_entry(desc, &wdm_device_list, device_list)
 141                 if (desc->intf == intf)
 142                         break;
 143         spin_unlock(&wdm_device_list_lock);
 144
 145         return desc;
 146 }
 147
 148 static struct wdm_device *wdm_find_device_by_minor(int minor)
 149 {
 150         struct wdm_device *desc = NULL;
 151
 152         spin_lock(&wdm_device_list_lock);
 153         list_for_each_entry(desc, &wdm_device_list, device_list)
 154                 if (desc->intf->minor == minor)
 155                         break;
 156         spin_unlock(&wdm_device_list_lock);
 157
 158         return desc;
 159 }
 160
 161 /* --- callbacks --- */
 162 static void wdm_out_callback(struct urb *urb)
 163 {
 164         struct wdm_device *desc;
 165         desc = urb->context;
 166         spin_lock(&desc->iuspin);
 167         desc->werr = urb->status;
 168         spin_unlock(&desc->iuspin);
 169         kfree(desc->outbuf);
 170         desc->outbuf = NULL;
 171         clear_bit(WDM_IN_USE, &desc->flags);
 172         wake_up(&desc->wait);
 173 }
 174
 175 static void wdm_in_callback(struct urb *urb)
 176 {
 177         struct wdm_device *desc = urb->context;
 178         int status = urb->status;
 179
 180         spin_lock(&desc->iuspin);
 181         clear_bit(WDM_RESPONDING, &desc->flags);
 182
 183         if (status) {
 184                 switch (status) {
 185                 case -ENOENT:
 186                         dev_dbg(&desc->intf->dev,
 187                                 "nonzero urb status received: -ENOENT");
 188                         goto skip_error;
 189                 case -ECONNRESET:
 190                         dev_dbg(&desc->intf->dev,
 191                                 "nonzero urb status received: -ECONNRESET");
 192                         goto skip_error;
 193                 case -ESHUTDOWN:
 194                         dev_dbg(&desc->intf->dev,
 195                                 "nonzero urb status received: -ESHUTDOWN");
 196                         goto skip_error;
 197                 case -EPIPE:
 198                         dev_err(&desc->intf->dev,
 199                                 "nonzero urb status received: -EPIPE\n");
 200                         break;
 201                 default:
 202                         dev_err(&desc->intf->dev,
 203                                 "Unexpected error %d\n", status);
 204                         break;
 205                 }
 206         }
 207
 208         desc->rerr = status;
 209         desc->reslength = urb->actual_length;
 210         memmove(desc->ubuf + desc->length, desc->inbuf, desc->reslength);
 211         desc->length += desc->reslength;
 212 skip_error:
 213         wake_up(&desc->wait);
 214
 215         set_bit(WDM_READ, &desc->flags);
 216         spin_unlock(&desc->iuspin);
 217 }
 218
 219 static void wdm_int_callback(struct urb *urb)
 220 {
 221         int rv = 0;
 222         int status = urb->status;
 223         struct wdm_device *desc;
 224         struct usb_cdc_notification *dr;
 225
 226         desc = urb->context;
 227         dr = (struct usb_cdc_notification *)desc->sbuf;
 228
 229         if (status) {
 230                 switch (status) {
 231                 case -ESHUTDOWN:
 232                 case -ENOENT:
 233                 case -ECONNRESET:
 234                         return; /* unplug */
 235                 case -EPIPE:
 236                         set_bit(WDM_INT_STALL, &desc->flags);
 237                         dev_err(&desc->intf->dev, "Stall on int endpoint\n");
 238                         goto sw; /* halt is cleared in work */
 239                 default:
 240                         dev_err(&desc->intf->dev,
 241                                 "nonzero urb status received: %d\n", status);
 242                         break;
 243                 }
 244         }
 245
 246         if (urb->actual_length < sizeof(struct usb_cdc_notification)) {
 247                 dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n",
 248                         urb->actual_length);
 249                 goto exit;
 250         }
 251
 252         switch (dr->bNotificationType) {
 253         case USB_CDC_NOTIFY_RESPONSE_AVAILABLE:
 254                 dev_dbg(&desc->intf->dev,
 255                         "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d",
 256                         dr->wIndex, dr->wLength);
 257                 break;
 258
 259         case USB_CDC_NOTIFY_NETWORK_CONNECTION:
 260
 261                 dev_dbg(&desc->intf->dev,
 262                         "NOTIFY_NETWORK_CONNECTION %s network",
 263                         dr->wValue ? "connected to" : "disconnected from");
 264                 goto exit;
 265         default:
 266                 clear_bit(WDM_POLL_RUNNING, &desc->flags);
 267                 dev_err(&desc->intf->dev,
 268                         "unknown notification %d received: index %d len %d\n",
 269                         dr->bNotificationType, dr->wIndex, dr->wLength);
 270                 goto exit;
 271         }
 272
 273         spin_lock(&desc->iuspin);
 274         clear_bit(WDM_READ, &desc->flags);
 275         set_bit(WDM_RESPONDING, &desc->flags);
 276         if (!test_bit(WDM_DISCONNECTING, &desc->flags)
 277                 && !test_bit(WDM_SUSPENDING, &desc->flags)) {
 278                 rv = usb_submit_urb(desc->response, GFP_ATOMIC);
 279                 dev_dbg(&desc->intf->dev, "%s: usb_submit_urb %d",
 280                         __func__, rv);
 281         }
 282         spin_unlock(&desc->iuspin);
 283         if (rv < 0) {
 284                 clear_bit(WDM_RESPONDING, &desc->flags);
 285                 if (rv == -EPERM)
 286                         return;
 287                 if (rv == -ENOMEM) {
 288 sw:
 289                         rv = schedule_work(&desc->rxwork);
 290                         if (rv)
 291                                 dev_err(&desc->intf->dev,
 292                                         "Cannot schedule work\n");
 293                 }
 294         }
 295 exit:
 296         rv = usb_submit_urb(urb, GFP_ATOMIC);
 297         if (rv)
 298                 dev_err(&desc->intf->dev,
 299                         "%s - usb_submit_urb failed with result %d\n",
 300                         __func__, rv);
 301
 302 }
 303
 304 static void kill_urbs(struct wdm_device *desc)
 305 {
 306         /* the order here is essential */
 307         usb_kill_urb(desc->command);
 308         usb_kill_urb(desc->validity);
 309         usb_kill_urb(desc->response);
 310 }
 311
 312 static void free_urbs(struct wdm_device *desc)
 313 {
 314         usb_free_urb(desc->validity);
 315         usb_free_urb(desc->response);
 316         usb_free_urb(desc->command);
 317 }
 318
 319 static void cleanup(struct wdm_device *desc)
 320 {
 321         kfree(desc->sbuf);
 322         kfree(desc->inbuf);
 323         kfree(desc->orq);
 324         kfree(desc->irq);
 325         kfree(desc->ubuf);
 326         free_urbs(desc);
 327         kfree(desc);
 328 }
 329
 330 static ssize_t wdm_write
 331 (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 332 {
 333         u8 *buf;
 334         int rv = -EMSGSIZE, r, we;
 335         struct wdm_device *desc = file->private_data;
 336         struct usb_ctrlrequest *req;
 337
 338         if (count > desc->wMaxCommand)
 339                 count = desc->wMaxCommand;
 340
 341         spin_lock_irq(&desc->iuspin);
 342         we = desc->werr;
 343         desc->werr = 0;
 344         spin_unlock_irq(&desc->iuspin);
 345         if (we < 0)
 346                 return -EIO;
 347
 348         buf = kmalloc(count, GFP_KERNEL);
 349         if (!buf) {
 350                 rv = -ENOMEM;
 351                 goto outnl;
 352         }
 353
 354         r = copy_from_user(buf, buffer, count);
 355         if (r > 0) {
 356                 kfree(buf);
 357                 rv = -EFAULT;
 358                 goto outnl;
 359         }
 360
 361         /* concurrent writes and disconnect */
 362         r = mutex_lock_interruptible(&desc->wlock);
 363         rv = -ERESTARTSYS;
 364         if (r) {
 365                 kfree(buf);
 366                 goto outnl;
 367         }
 368
 369         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 370                 kfree(buf);
 371                 rv = -ENODEV;
 372                 goto outnp;
 373         }
 374
 375         r = usb_autopm_get_interface(desc->intf);
 376         if (r < 0) {
 377                 kfree(buf);
 378                 rv = usb_translate_errors(r);
 379                 goto outnp;
 380         }
 381
 382         if (!(file->f_flags & O_NONBLOCK))
 383                 r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
 384                                                                 &desc->flags));
 385         else
 386                 if (test_bit(WDM_IN_USE, &desc->flags))
 387                         r = -EAGAIN;
 388
 389         if (test_bit(WDM_RESETTING, &desc->flags))
 390                 r = -EIO;
 391
 392         if (r < 0) {
 393                 kfree(buf);
 394                 rv = r;
 395                 goto out;
 396         }
 397
 398         req = desc->orq;
 399         usb_fill_control_urb(
 400                 desc->command,
 401                 interface_to_usbdev(desc->intf),
 402                 /* using common endpoint 0 */
 403                 usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
 404                 (unsigned char *)req,
 405                 buf,
 406                 count,
 407                 wdm_out_callback,
 408                 desc
 409         );
 410
 411         req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
 412                              USB_RECIP_INTERFACE);
 413         req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
 414         req->wValue = 0;
 415         req->wIndex = desc->inum;
 416         req->wLength = cpu_to_le16(count);
 417         set_bit(WDM_IN_USE, &desc->flags);
 418         desc->outbuf = buf;
 419
 420         rv = usb_submit_urb(desc->command, GFP_KERNEL);
 421         if (rv < 0) {
 422                 kfree(buf);
 423                 desc->outbuf = NULL;
 424                 clear_bit(WDM_IN_USE, &desc->flags);
 425                 dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
 426                 rv = usb_translate_errors(rv);
 427         } else {
 428                 dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d",
 429                         req->wIndex);
 430         }
 431 out:
 432         usb_autopm_put_interface(desc->intf);
 433 outnp:
 434         mutex_unlock(&desc->wlock);
 435 outnl:
 436         return rv < 0 ? rv : count;
 437 }
 438
 439 static ssize_t wdm_read
 440 (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 441 {
 442         int rv, cntr;
 443         int i = 0;
 444         struct wdm_device *desc = file->private_data;
 445
 446
 447         rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
 448         if (rv < 0)
 449                 return -ERESTARTSYS;
 450
 451         cntr = ACCESS_ONCE(desc->length);
 452         if (cntr == 0) {
 453                 desc->read = 0;
 454 retry:
 455                 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 456                         rv = -ENODEV;
 457                         goto err;
 458                 }
 459                 i++;
 460                 if (file->f_flags & O_NONBLOCK) {
 461                         if (!test_bit(WDM_READ, &desc->flags)) {
 462                                 rv = cntr ? cntr : -EAGAIN;
 463                                 goto err;
 464                         }
 465                         rv = 0;
 466                 } else {
 467                         rv = wait_event_interruptible(desc->wait,
 468                                 test_bit(WDM_READ, &desc->flags));
 469                 }
 470
 471                 /* may have happened while we slept */
 472                 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 473                         rv = -ENODEV;
 474                         goto err;
 475                 }
 476                 if (test_bit(WDM_RESETTING, &desc->flags)) {
 477                         rv = -EIO;
 478                         goto err;
 479                 }
 480                 usb_mark_last_busy(interface_to_usbdev(desc->intf));
 481                 if (rv < 0) {
 482                         rv = -ERESTARTSYS;
 483                         goto err;
 484                 }
 485
 486                 spin_lock_irq(&desc->iuspin);
 487
 488                 if (desc->rerr) { /* read completed, error happened */
 489                         desc->rerr = 0;
 490                         spin_unlock_irq(&desc->iuspin);
 491                         rv = -EIO;
 492                         goto err;
 493                 }
 494                 /*
 495                  * recheck whether we've lost the race
 496                  * against the completion handler
 497                  */
 498                 if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */
 499                         spin_unlock_irq(&desc->iuspin);
 500                         goto retry;
 501                 }
 502                 if (!desc->reslength) { /* zero length read */
 503                         spin_unlock_irq(&desc->iuspin);
 504                         goto retry;
 505                 }
 506                 cntr = desc->length;
 507                 spin_unlock_irq(&desc->iuspin);
 508         }
 509
 510         if (cntr > count)
 511                 cntr = count;
 512         rv = copy_to_user(buffer, desc->ubuf, cntr);
 513         if (rv > 0) {
 514                 rv = -EFAULT;
 515                 goto err;
 516         }
 517
 518         spin_lock_irq(&desc->iuspin);
 519
 520         for (i = 0; i < desc->length - cntr; i++)
 521                 desc->ubuf[i] = desc->ubuf[i + cntr];
 522
 523         desc->length -= cntr;
 524         /* in case we had outstanding data */
 525         if (!desc->length)
 526                 clear_bit(WDM_READ, &desc->flags);
 527
 528         spin_unlock_irq(&desc->iuspin);
 529
 530         rv = cntr;
 531
 532 err:
 533         mutex_unlock(&desc->rlock);
 534         return rv;
 535 }
 536
 537 static int wdm_flush(struct file *file, fl_owner_t id)
 538 {
 539         struct wdm_device *desc = file->private_data;
 540
 541         wait_event(desc->wait, !test_bit(WDM_IN_USE, &desc->flags));
 542
 543         /* cannot dereference desc->intf if WDM_DISCONNECTING */
 544         if (desc->werr < 0 && !test_bit(WDM_DISCONNECTING, &desc->flags))
 545                 dev_err(&desc->intf->dev, "Error in flush path: %d\n",
 546                         desc->werr);
 547
 548         return usb_translate_errors(desc->werr);
 549 }
 550
 551 static unsigned int wdm_poll(struct file *file, struct poll_table_struct *wait)
 552 {
 553         struct wdm_device *desc = file->private_data;
 554         unsigned long flags;
 555         unsigned int mask = 0;
 556
 557         spin_lock_irqsave(&desc->iuspin, flags);
 558         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 559                 mask = POLLHUP | POLLERR;
 560                 spin_unlock_irqrestore(&desc->iuspin, flags);
 561                 goto desc_out;
 562         }
 563         if (test_bit(WDM_READ, &desc->flags))
 564                 mask = POLLIN | POLLRDNORM;
 565         if (desc->rerr || desc->werr)
 566                 mask |= POLLERR;
 567         if (!test_bit(WDM_IN_USE, &desc->flags))
 568                 mask |= POLLOUT | POLLWRNORM;
 569         spin_unlock_irqrestore(&desc->iuspin, flags);
 570
 571         poll_wait(file, &desc->wait, wait);
 572
 573 desc_out:
 574         return mask;
 575 }
 576
 577 static int wdm_open(struct inode *inode, struct file *file)
 578 {
 579         int minor = iminor(inode);
 580         int rv = -ENODEV;
 581         struct usb_interface *intf;
 582         struct wdm_device *desc;
 583
 584         mutex_lock(&wdm_mutex);
 585         desc = wdm_find_device_by_minor(minor);
 586         if (!desc)
 587                 goto out;
 588
 589         intf = desc->intf;
 590         if (test_bit(WDM_DISCONNECTING, &desc->flags))
 591                 goto out;
 592         file->private_data = desc;
 593
 594         rv = usb_autopm_get_interface(desc->intf);
 595         if (rv < 0) {
 596                 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
 597                 goto out;
 598         }
 599
 600         /* using write lock to protect desc->count */
 601         mutex_lock(&desc->wlock);
 602         if (!desc->count++) {
 603                 desc->werr = 0;
 604                 desc->rerr = 0;
 605                 rv = usb_submit_urb(desc->validity, GFP_KERNEL);
 606                 if (rv < 0) {
 607                         desc->count--;
 608                         dev_err(&desc->intf->dev,
 609                                 "Error submitting int urb - %d\n", rv);
 610                         rv = usb_translate_errors(rv);
 611                 }
 612         } else {
 613                 rv = 0;
 614         }
 615         mutex_unlock(&desc->wlock);
 616         if (desc->count == 1)
 617                 desc->manage_power(intf, 1);
 618         usb_autopm_put_interface(desc->intf);
 619 out:
 620         mutex_unlock(&wdm_mutex);
 621         return rv;
 622 }
 623
 624 static int wdm_release(struct inode *inode, struct file *file)
 625 {
 626         struct wdm_device *desc = file->private_data;
 627
 628         mutex_lock(&wdm_mutex);
 629
 630         /* using write lock to protect desc->count */
 631         mutex_lock(&desc->wlock);
 632         desc->count--;
 633         mutex_unlock(&desc->wlock);
 634
 635         if (!desc->count) {
 636                 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
 637                         dev_dbg(&desc->intf->dev, "wdm_release: cleanup");
 638                         kill_urbs(desc);
 639                         desc->manage_power(desc->intf, 0);
 640                 } else {
 641                         /* must avoid dev_printk here as desc->intf is invalid */
 642                         pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
 643                         cleanup(desc);
 644                 }
 645         }
 646         mutex_unlock(&wdm_mutex);
 647         return 0;
 648 }
 649
 650 static const struct file_operations wdm_fops = {
 651         .owner =        THIS_MODULE,
 652         .read =         wdm_read,
 653         .write =        wdm_write,
 654         .open =         wdm_open,
 655         .flush =        wdm_flush,
 656         .release =      wdm_release,
 657         .poll =         wdm_poll,
 658         .llseek =       noop_llseek,
 659 };
 660
 661 static struct usb_class_driver wdm_class = {
 662         .name =         "cdc-wdm%d",
 663         .fops =         &wdm_fops,
 664         .minor_base =   WDM_MINOR_BASE,
 665 };
 666
 667 /* --- error handling --- */
 668 static void wdm_rxwork(struct work_struct *work)
 669 {
 670         struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
 671         unsigned long flags;
 672         int rv;
 673
 674         spin_lock_irqsave(&desc->iuspin, flags);
 675         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 676                 spin_unlock_irqrestore(&desc->iuspin, flags);
 677         } else {
 678                 spin_unlock_irqrestore(&desc->iuspin, flags);
 679                 rv = usb_submit_urb(desc->response, GFP_KERNEL);
 680                 if (rv < 0 && rv != -EPERM) {
 681                         spin_lock_irqsave(&desc->iuspin, flags);
 682                         if (!test_bit(WDM_DISCONNECTING, &desc->flags))
 683                                 schedule_work(&desc->rxwork);
 684                         spin_unlock_irqrestore(&desc->iuspin, flags);
 685                 }
 686         }
 687 }
 688
 689 /* --- hotplug --- */
 690
 691 static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
 692                 u16 bufsize, int (*manage_power)(struct usb_interface *, int))
 693 {
 694         int rv = -ENOMEM;
 695         struct wdm_device *desc;
 696
 697         desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
 698         if (!desc)
 699                 goto out;
 700         INIT_LIST_HEAD(&desc->device_list);
 701         mutex_init(&desc->rlock);
 702         mutex_init(&desc->wlock);
 703         spin_lock_init(&desc->iuspin);
 704         init_waitqueue_head(&desc->wait);
 705         desc->wMaxCommand = bufsize;
 706         /* this will be expanded and needed in hardware endianness */
 707         desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
 708         desc->intf = intf;
 709         INIT_WORK(&desc->rxwork, wdm_rxwork);
 710
 711         rv = -EINVAL;
 712         if (!usb_endpoint_is_int_in(ep))
 713                 goto err;
 714
 715         desc->wMaxPacketSize = usb_endpoint_maxp(ep);
 716
 717         desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
 718         if (!desc->orq)
 719                 goto err;
 720         desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
 721         if (!desc->irq)
 722                 goto err;
 723
 724         desc->validity = usb_alloc_urb(0, GFP_KERNEL);
 725         if (!desc->validity)
 726                 goto err;
 727
 728         desc->response = usb_alloc_urb(0, GFP_KERNEL);
 729         if (!desc->response)
 730                 goto err;
 731
 732         desc->command = usb_alloc_urb(0, GFP_KERNEL);
 733         if (!desc->command)
 734                 goto err;
 735
 736         desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
 737         if (!desc->ubuf)
 738                 goto err;
 739
 740         desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);
 741         if (!desc->sbuf)
 742                 goto err;
 743
 744         desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
 745         if (!desc->inbuf)
 746                 goto err;
 747
 748         usb_fill_int_urb(
 749                 desc->validity,
 750                 interface_to_usbdev(intf),
 751                 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
 752                 desc->sbuf,
 753                 desc->wMaxPacketSize,
 754                 wdm_int_callback,
 755                 desc,
 756                 ep->bInterval
 757         );
 758
 759         desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
 760         desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
 761         desc->irq->wValue = 0;
 762         desc->irq->wIndex = desc->inum;
 763         desc->irq->wLength = cpu_to_le16(desc->wMaxCommand);
 764
 765         usb_fill_control_urb(
 766                 desc->response,
 767                 interface_to_usbdev(intf),
 768                 /* using common endpoint 0 */
 769                 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
 770                 (unsigned char *)desc->irq,
 771                 desc->inbuf,
 772                 desc->wMaxCommand,
 773                 wdm_in_callback,
 774                 desc
 775         );
 776
 777         desc->manage_power = manage_power;
 778
 779         spin_lock(&wdm_device_list_lock);
 780         list_add(&desc->device_list, &wdm_device_list);
 781         spin_unlock(&wdm_device_list_lock);
 782
 783         rv = usb_register_dev(intf, &wdm_class);
 784         if (rv < 0)
 785                 goto err;
 786         else
 787                 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev));
 788 out:
 789         return rv;
 790 err:
 791         spin_lock(&wdm_device_list_lock);
 792         list_del(&desc->device_list);
 793         spin_unlock(&wdm_device_list_lock);
 794         cleanup(desc);
 795         return rv;
 796 }
 797
 798 static int wdm_manage_power(struct usb_interface *intf, int on)
 799 {
 800         /* need autopm_get/put here to ensure the usbcore sees the new value */
 801         int rv = usb_autopm_get_interface(intf);
 802         if (rv < 0)
 803                 goto err;
 804
 805         intf->needs_remote_wakeup = on;
 806         usb_autopm_put_interface(intf);
 807 err:
 808         return rv;
 809 }
 810
 811 static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
 812 {
 813         int rv = -EINVAL;
 814         struct usb_host_interface *iface;
 815         struct usb_endpoint_descriptor *ep;
 816         struct usb_cdc_dmm_desc *dmhd;
 817         u8 *buffer = intf->altsetting->extra;
 818         int buflen = intf->altsetting->extralen;
 819         u16 maxcom = WDM_DEFAULT_BUFSIZE;
 820
 821         if (!buffer)
 822                 goto err;
 823         while (buflen > 2) {
 824                 if (buffer[1] != USB_DT_CS_INTERFACE) {
 825                         dev_err(&intf->dev, "skipping garbage\n");
 826                         goto next_desc;
 827                 }
 828
 829                 switch (buffer[2]) {
 830                 case USB_CDC_HEADER_TYPE:
 831                         break;
 832                 case USB_CDC_DMM_TYPE:
 833                         dmhd = (struct usb_cdc_dmm_desc *)buffer;
 834                         maxcom = le16_to_cpu(dmhd->wMaxCommand);
 835                         dev_dbg(&intf->dev,
 836                                 "Finding maximum buffer length: %d", maxcom);
 837                         break;
 838                 default:
 839                         dev_err(&intf->dev,
 840                                 "Ignoring extra header, type %d, length %d\n",
 841                                 buffer[2], buffer[0]);
 842                         break;
 843                 }
 844 next_desc:
 845                 buflen -= buffer[0];
 846                 buffer += buffer[0];
 847         }
 848
 849         iface = intf->cur_altsetting;
 850         if (iface->desc.bNumEndpoints != 1)
 851                 goto err;
 852         ep = &iface->endpoint[0].desc;
 853
 854         rv = wdm_create(intf, ep, maxcom, &wdm_manage_power);
 855
 856 err:
 857         return rv;
 858 }
 859
 860 /**
 861  * usb_cdc_wdm_register - register a WDM subdriver
 862  * @intf: usb interface the subdriver will associate with
 863  * @ep: interrupt endpoint to monitor for notifications
 864  * @bufsize: maximum message size to support for read/write
 865  *
 866  * Create WDM usb class character device and associate it with intf
 867  * without binding, allowing another driver to manage the interface.
 868  *
 869  * The subdriver will manage the given interrupt endpoint exclusively
 870  * and will issue control requests referring to the given intf. It
 871  * will otherwise avoid interferring, and in particular not do
 872  * usb_set_intfdata/usb_get_intfdata on intf.
 873  *
 874  * The return value is a pointer to the subdriver's struct usb_driver.
 875  * The registering driver is responsible for calling this subdriver's
 876  * disconnect, suspend, resume, pre_reset and post_reset methods from
 877  * its own.
 878  */
 879 struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,
 880                                         struct usb_endpoint_descriptor *ep,
 881                                         int bufsize,
 882                                         int (*manage_power)(struct usb_interface *, int))
 883 {
 884         int rv = -EINVAL;
 885
 886         rv = wdm_create(intf, ep, bufsize, manage_power);
 887         if (rv < 0)
 888                 goto err;
 889
 890         return &wdm_driver;
 891 err:
 892         return ERR_PTR(rv);
 893 }
 894 EXPORT_SYMBOL(usb_cdc_wdm_register);
 895
 896 static void wdm_disconnect(struct usb_interface *intf)
 897 {
 898         struct wdm_device *desc;
 899         unsigned long flags;
 900
 901         usb_deregister_dev(intf, &wdm_class);
 902         desc = wdm_find_device(intf);
 903         mutex_lock(&wdm_mutex);
 904
 905         /* the spinlock makes sure no new urbs are generated in the callbacks */
 906         spin_lock_irqsave(&desc->iuspin, flags);
 907         set_bit(WDM_DISCONNECTING, &desc->flags);
 908         set_bit(WDM_READ, &desc->flags);
 909         /* to terminate pending flushes */
 910         clear_bit(WDM_IN_USE, &desc->flags);
 911         spin_unlock_irqrestore(&desc->iuspin, flags);
 912         wake_up_all(&desc->wait);
 913         mutex_lock(&desc->rlock);
 914         mutex_lock(&desc->wlock);
 915         kill_urbs(desc);
 916         cancel_work_sync(&desc->rxwork);
 917         mutex_unlock(&desc->wlock);
 918         mutex_unlock(&desc->rlock);
 919
 920         /* the desc->intf pointer used as list key is now invalid */
 921         spin_lock(&wdm_device_list_lock);
 922         list_del(&desc->device_list);
 923         spin_unlock(&wdm_device_list_lock);
 924
 925         if (!desc->count)
 926                 cleanup(desc);
 927         else
 928                 dev_dbg(&intf->dev, "%s: %d open files - postponing cleanup\n", __func__, desc->count);
 929         mutex_unlock(&wdm_mutex);
 930 }
 931
 932 #ifdef CONFIG_PM
 933 static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
 934 {
 935         struct wdm_device *desc = wdm_find_device(intf);
 936         int rv = 0;
 937
 938         dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
 939
 940         /* if this is an autosuspend the caller does the locking */
 941         if (!PMSG_IS_AUTO(message)) {
 942                 mutex_lock(&desc->rlock);
 943                 mutex_lock(&desc->wlock);
 944         }
 945         spin_lock_irq(&desc->iuspin);
 946
 947         if (PMSG_IS_AUTO(message) &&
 948                         (test_bit(WDM_IN_USE, &desc->flags)
 949                         || test_bit(WDM_RESPONDING, &desc->flags))) {
 950                 spin_unlock_irq(&desc->iuspin);
 951                 rv = -EBUSY;
 952         } else {
 953
 954                 set_bit(WDM_SUSPENDING, &desc->flags);
 955                 spin_unlock_irq(&desc->iuspin);
 956                 /* callback submits work - order is essential */
 957                 kill_urbs(desc);
 958                 cancel_work_sync(&desc->rxwork);
 959         }
 960         if (!PMSG_IS_AUTO(message)) {
 961                 mutex_unlock(&desc->wlock);
 962                 mutex_unlock(&desc->rlock);
 963         }
 964
 965         return rv;
 966 }
 967 #endif
 968
 969 static int recover_from_urb_loss(struct wdm_device *desc)
 970 {
 971         int rv = 0;
 972
 973         if (desc->count) {
 974                 rv = usb_submit_urb(desc->validity, GFP_NOIO);
 975                 if (rv < 0)
 976                         dev_err(&desc->intf->dev,
 977                                 "Error resume submitting int urb - %d\n", rv);
 978         }
 979         return rv;
 980 }
 981
 982 #ifdef CONFIG_PM
 983 static int wdm_resume(struct usb_interface *intf)
 984 {
 985         struct wdm_device *desc = wdm_find_device(intf);
 986         int rv;
 987
 988         dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
 989
 990         clear_bit(WDM_SUSPENDING, &desc->flags);
 991         rv = recover_from_urb_loss(desc);
 992
 993         return rv;
 994 }
 995 #endif
 996
 997 static int wdm_pre_reset(struct usb_interface *intf)
 998 {
 999         struct wdm_device *desc = wdm_find_device(intf);
1000
1001         /*
1002          * we notify everybody using poll of
1003          * an exceptional situation
1004          * must be done before recovery lest a spontaneous
1005          * message from the device is lost
1006          */
1007         spin_lock_irq(&desc->iuspin);
1008         set_bit(WDM_RESETTING, &desc->flags);   /* inform read/write */
1009         set_bit(WDM_READ, &desc->flags);        /* unblock read */
1010         clear_bit(WDM_IN_USE, &desc->flags);    /* unblock write */
1011         desc->rerr = -EINTR;
1012         spin_unlock_irq(&desc->iuspin);
1013         wake_up_all(&desc->wait);
1014         mutex_lock(&desc->rlock);
1015         mutex_lock(&desc->wlock);
1016         kill_urbs(desc);
1017         cancel_work_sync(&desc->rxwork);
1018         return 0;
1019 }
1020
1021 static int wdm_post_reset(struct usb_interface *intf)
1022 {
1023         struct wdm_device *desc = wdm_find_device(intf);
1024         int rv;
1025
1026         clear_bit(WDM_RESETTING, &desc->flags);
1027         rv = recover_from_urb_loss(desc);
1028         mutex_unlock(&desc->wlock);
1029         mutex_unlock(&desc->rlock);
1030         return 0;
1031 }
1032
1033 static struct usb_driver wdm_driver = {
1034         .name =         "cdc_wdm",
1035         .probe =        wdm_probe,
1036         .disconnect =   wdm_disconnect,
1037 #ifdef CONFIG_PM
1038         .suspend =      wdm_suspend,
1039         .resume =       wdm_resume,
1040         .reset_resume = wdm_resume,
1041 #endif
1042         .pre_reset =    wdm_pre_reset,
1043         .post_reset =   wdm_post_reset,
1044         .id_table =     wdm_ids,
1045         .supports_autosuspend = 1,
1046         .disable_hub_initiated_lpm = 1,
1047 };
1048
1049 module_usb_driver(wdm_driver);
1050
1051 MODULE_AUTHOR(DRIVER_AUTHOR);
1052 MODULE_DESCRIPTION(DRIVER_DESC);
1053 MODULE_LICENSE("GPL");