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                         dev_dbg(&desc->intf->dev, "%s: zero length - clearing WDM_READ\n", __func__);
 504                         clear_bit(WDM_READ, &desc->flags);
 505                         spin_unlock_irq(&desc->iuspin);
 506                         goto retry;
 507                 }
 508                 cntr = desc->length;
 509                 spin_unlock_irq(&desc->iuspin);
 510         }
 511
 512         if (cntr > count)
 513                 cntr = count;
 514         rv = copy_to_user(buffer, desc->ubuf, cntr);
 515         if (rv > 0) {
 516                 rv = -EFAULT;
 517                 goto err;
 518         }
 519
 520         spin_lock_irq(&desc->iuspin);
 521
 522         for (i = 0; i < desc->length - cntr; i++)
 523                 desc->ubuf[i] = desc->ubuf[i + cntr];
 524
 525         desc->length -= cntr;
 526         /* in case we had outstanding data */
 527         if (!desc->length)
 528                 clear_bit(WDM_READ, &desc->flags);
 529
 530         spin_unlock_irq(&desc->iuspin);
 531
 532         rv = cntr;
 533
 534 err:
 535         mutex_unlock(&desc->rlock);
 536         return rv;
 537 }
 538
 539 static int wdm_flush(struct file *file, fl_owner_t id)
 540 {
 541         struct wdm_device *desc = file->private_data;
 542
 543         wait_event(desc->wait, !test_bit(WDM_IN_USE, &desc->flags));
 544
 545         /* cannot dereference desc->intf if WDM_DISCONNECTING */
 546         if (desc->werr < 0 && !test_bit(WDM_DISCONNECTING, &desc->flags))
 547                 dev_err(&desc->intf->dev, "Error in flush path: %d\n",
 548                         desc->werr);
 549
 550         return usb_translate_errors(desc->werr);
 551 }
 552
 553 static unsigned int wdm_poll(struct file *file, struct poll_table_struct *wait)
 554 {
 555         struct wdm_device *desc = file->private_data;
 556         unsigned long flags;
 557         unsigned int mask = 0;
 558
 559         spin_lock_irqsave(&desc->iuspin, flags);
 560         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 561                 mask = POLLHUP | POLLERR;
 562                 spin_unlock_irqrestore(&desc->iuspin, flags);
 563                 goto desc_out;
 564         }
 565         if (test_bit(WDM_READ, &desc->flags))
 566                 mask = POLLIN | POLLRDNORM;
 567         if (desc->rerr || desc->werr)
 568                 mask |= POLLERR;
 569         if (!test_bit(WDM_IN_USE, &desc->flags))
 570                 mask |= POLLOUT | POLLWRNORM;
 571         spin_unlock_irqrestore(&desc->iuspin, flags);
 572
 573         poll_wait(file, &desc->wait, wait);
 574
 575 desc_out:
 576         return mask;
 577 }
 578
 579 static int wdm_open(struct inode *inode, struct file *file)
 580 {
 581         int minor = iminor(inode);
 582         int rv = -ENODEV;
 583         struct usb_interface *intf;
 584         struct wdm_device *desc;
 585
 586         mutex_lock(&wdm_mutex);
 587         desc = wdm_find_device_by_minor(minor);
 588         if (!desc)
 589                 goto out;
 590
 591         intf = desc->intf;
 592         if (test_bit(WDM_DISCONNECTING, &desc->flags))
 593                 goto out;
 594         file->private_data = desc;
 595
 596         rv = usb_autopm_get_interface(desc->intf);
 597         if (rv < 0) {
 598                 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
 599                 goto out;
 600         }
 601
 602         /* using write lock to protect desc->count */
 603         mutex_lock(&desc->wlock);
 604         if (!desc->count++) {
 605                 desc->werr = 0;
 606                 desc->rerr = 0;
 607                 rv = usb_submit_urb(desc->validity, GFP_KERNEL);
 608                 if (rv < 0) {
 609                         desc->count--;
 610                         dev_err(&desc->intf->dev,
 611                                 "Error submitting int urb - %d\n", rv);
 612                         rv = usb_translate_errors(rv);
 613                 }
 614         } else {
 615                 rv = 0;
 616         }
 617         mutex_unlock(&desc->wlock);
 618         if (desc->count == 1)
 619                 desc->manage_power(intf, 1);
 620         usb_autopm_put_interface(desc->intf);
 621 out:
 622         mutex_unlock(&wdm_mutex);
 623         return rv;
 624 }
 625
 626 static int wdm_release(struct inode *inode, struct file *file)
 627 {
 628         struct wdm_device *desc = file->private_data;
 629
 630         mutex_lock(&wdm_mutex);
 631
 632         /* using write lock to protect desc->count */
 633         mutex_lock(&desc->wlock);
 634         desc->count--;
 635         mutex_unlock(&desc->wlock);
 636
 637         if (!desc->count) {
 638                 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
 639                         dev_dbg(&desc->intf->dev, "wdm_release: cleanup");
 640                         kill_urbs(desc);
 641                         desc->manage_power(desc->intf, 0);
 642                 } else {
 643                         /* must avoid dev_printk here as desc->intf is invalid */
 644                         pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
 645                         cleanup(desc);
 646                 }
 647         }
 648         mutex_unlock(&wdm_mutex);
 649         return 0;
 650 }
 651
 652 static const struct file_operations wdm_fops = {
 653         .owner =        THIS_MODULE,
 654         .read =         wdm_read,
 655         .write =        wdm_write,
 656         .open =         wdm_open,
 657         .flush =        wdm_flush,
 658         .release =      wdm_release,
 659         .poll =         wdm_poll,
 660         .llseek =       noop_llseek,
 661 };
 662
 663 static struct usb_class_driver wdm_class = {
 664         .name =         "cdc-wdm%d",
 665         .fops =         &wdm_fops,
 666         .minor_base =   WDM_MINOR_BASE,
 667 };
 668
 669 /* --- error handling --- */
 670 static void wdm_rxwork(struct work_struct *work)
 671 {
 672         struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
 673         unsigned long flags;
 674         int rv;
 675
 676         spin_lock_irqsave(&desc->iuspin, flags);
 677         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 678                 spin_unlock_irqrestore(&desc->iuspin, flags);
 679         } else {
 680                 spin_unlock_irqrestore(&desc->iuspin, flags);
 681                 rv = usb_submit_urb(desc->response, GFP_KERNEL);
 682                 if (rv < 0 && rv != -EPERM) {
 683                         spin_lock_irqsave(&desc->iuspin, flags);
 684                         if (!test_bit(WDM_DISCONNECTING, &desc->flags))
 685                                 schedule_work(&desc->rxwork);
 686                         spin_unlock_irqrestore(&desc->iuspin, flags);
 687                 }
 688         }
 689 }
 690
 691 /* --- hotplug --- */
 692
 693 static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
 694                 u16 bufsize, int (*manage_power)(struct usb_interface *, int))
 695 {
 696         int rv = -ENOMEM;
 697         struct wdm_device *desc;
 698
 699         desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
 700         if (!desc)
 701                 goto out;
 702         INIT_LIST_HEAD(&desc->device_list);
 703         mutex_init(&desc->rlock);
 704         mutex_init(&desc->wlock);
 705         spin_lock_init(&desc->iuspin);
 706         init_waitqueue_head(&desc->wait);
 707         desc->wMaxCommand = bufsize;
 708         /* this will be expanded and needed in hardware endianness */
 709         desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
 710         desc->intf = intf;
 711         INIT_WORK(&desc->rxwork, wdm_rxwork);
 712
 713         rv = -EINVAL;
 714         if (!usb_endpoint_is_int_in(ep))
 715                 goto err;
 716
 717         desc->wMaxPacketSize = usb_endpoint_maxp(ep);
 718
 719         desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
 720         if (!desc->orq)
 721                 goto err;
 722         desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
 723         if (!desc->irq)
 724                 goto err;
 725
 726         desc->validity = usb_alloc_urb(0, GFP_KERNEL);
 727         if (!desc->validity)
 728                 goto err;
 729
 730         desc->response = usb_alloc_urb(0, GFP_KERNEL);
 731         if (!desc->response)
 732                 goto err;
 733
 734         desc->command = usb_alloc_urb(0, GFP_KERNEL);
 735         if (!desc->command)
 736                 goto err;
 737
 738         desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
 739         if (!desc->ubuf)
 740                 goto err;
 741
 742         desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);
 743         if (!desc->sbuf)
 744                 goto err;
 745
 746         desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
 747         if (!desc->inbuf)
 748                 goto err;
 749
 750         usb_fill_int_urb(
 751                 desc->validity,
 752                 interface_to_usbdev(intf),
 753                 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
 754                 desc->sbuf,
 755                 desc->wMaxPacketSize,
 756                 wdm_int_callback,
 757                 desc,
 758                 ep->bInterval
 759         );
 760
 761         desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
 762         desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
 763         desc->irq->wValue = 0;
 764         desc->irq->wIndex = desc->inum;
 765         desc->irq->wLength = cpu_to_le16(desc->wMaxCommand);
 766
 767         usb_fill_control_urb(
 768                 desc->response,
 769                 interface_to_usbdev(intf),
 770                 /* using common endpoint 0 */
 771                 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
 772                 (unsigned char *)desc->irq,
 773                 desc->inbuf,
 774                 desc->wMaxCommand,
 775                 wdm_in_callback,
 776                 desc
 777         );
 778
 779         desc->manage_power = manage_power;
 780
 781         spin_lock(&wdm_device_list_lock);
 782         list_add(&desc->device_list, &wdm_device_list);
 783         spin_unlock(&wdm_device_list_lock);
 784
 785         rv = usb_register_dev(intf, &wdm_class);
 786         if (rv < 0)
 787                 goto err;
 788         else
 789                 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev));
 790 out:
 791         return rv;
 792 err:
 793         spin_lock(&wdm_device_list_lock);
 794         list_del(&desc->device_list);
 795         spin_unlock(&wdm_device_list_lock);
 796         cleanup(desc);
 797         return rv;
 798 }
 799
 800 static int wdm_manage_power(struct usb_interface *intf, int on)
 801 {
 802         /* need autopm_get/put here to ensure the usbcore sees the new value */
 803         int rv = usb_autopm_get_interface(intf);
 804         if (rv < 0)
 805                 goto err;
 806
 807         intf->needs_remote_wakeup = on;
 808         usb_autopm_put_interface(intf);
 809 err:
 810         return rv;
 811 }
 812
 813 static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
 814 {
 815         int rv = -EINVAL;
 816         struct usb_host_interface *iface;
 817         struct usb_endpoint_descriptor *ep;
 818         struct usb_cdc_dmm_desc *dmhd;
 819         u8 *buffer = intf->altsetting->extra;
 820         int buflen = intf->altsetting->extralen;
 821         u16 maxcom = WDM_DEFAULT_BUFSIZE;
 822
 823         if (!buffer)
 824                 goto err;
 825         while (buflen > 2) {
 826                 if (buffer[1] != USB_DT_CS_INTERFACE) {
 827                         dev_err(&intf->dev, "skipping garbage\n");
 828                         goto next_desc;
 829                 }
 830
 831                 switch (buffer[2]) {
 832                 case USB_CDC_HEADER_TYPE:
 833                         break;
 834                 case USB_CDC_DMM_TYPE:
 835                         dmhd = (struct usb_cdc_dmm_desc *)buffer;
 836                         maxcom = le16_to_cpu(dmhd->wMaxCommand);
 837                         dev_dbg(&intf->dev,
 838                                 "Finding maximum buffer length: %d", maxcom);
 839                         break;
 840                 default:
 841                         dev_err(&intf->dev,
 842                                 "Ignoring extra header, type %d, length %d\n",
 843                                 buffer[2], buffer[0]);
 844                         break;
 845                 }
 846 next_desc:
 847                 buflen -= buffer[0];
 848                 buffer += buffer[0];
 849         }
 850
 851         iface = intf->cur_altsetting;
 852         if (iface->desc.bNumEndpoints != 1)
 853                 goto err;
 854         ep = &iface->endpoint[0].desc;
 855
 856         rv = wdm_create(intf, ep, maxcom, &wdm_manage_power);
 857
 858 err:
 859         return rv;
 860 }
 861
 862 /**
 863  * usb_cdc_wdm_register - register a WDM subdriver
 864  * @intf: usb interface the subdriver will associate with
 865  * @ep: interrupt endpoint to monitor for notifications
 866  * @bufsize: maximum message size to support for read/write
 867  *
 868  * Create WDM usb class character device and associate it with intf
 869  * without binding, allowing another driver to manage the interface.
 870  *
 871  * The subdriver will manage the given interrupt endpoint exclusively
 872  * and will issue control requests referring to the given intf. It
 873  * will otherwise avoid interferring, and in particular not do
 874  * usb_set_intfdata/usb_get_intfdata on intf.
 875  *
 876  * The return value is a pointer to the subdriver's struct usb_driver.
 877  * The registering driver is responsible for calling this subdriver's
 878  * disconnect, suspend, resume, pre_reset and post_reset methods from
 879  * its own.
 880  */
 881 struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,
 882                                         struct usb_endpoint_descriptor *ep,
 883                                         int bufsize,
 884                                         int (*manage_power)(struct usb_interface *, int))
 885 {
 886         int rv = -EINVAL;
 887
 888         rv = wdm_create(intf, ep, bufsize, manage_power);
 889         if (rv < 0)
 890                 goto err;
 891
 892         return &wdm_driver;
 893 err:
 894         return ERR_PTR(rv);
 895 }
 896 EXPORT_SYMBOL(usb_cdc_wdm_register);
 897
 898 static void wdm_disconnect(struct usb_interface *intf)
 899 {
 900         struct wdm_device *desc;
 901         unsigned long flags;
 902
 903         usb_deregister_dev(intf, &wdm_class);
 904         desc = wdm_find_device(intf);
 905         mutex_lock(&wdm_mutex);
 906
 907         /* the spinlock makes sure no new urbs are generated in the callbacks */
 908         spin_lock_irqsave(&desc->iuspin, flags);
 909         set_bit(WDM_DISCONNECTING, &desc->flags);
 910         set_bit(WDM_READ, &desc->flags);
 911         /* to terminate pending flushes */
 912         clear_bit(WDM_IN_USE, &desc->flags);
 913         spin_unlock_irqrestore(&desc->iuspin, flags);
 914         wake_up_all(&desc->wait);
 915         mutex_lock(&desc->rlock);
 916         mutex_lock(&desc->wlock);
 917         kill_urbs(desc);
 918         cancel_work_sync(&desc->rxwork);
 919         mutex_unlock(&desc->wlock);
 920         mutex_unlock(&desc->rlock);
 921
 922         /* the desc->intf pointer used as list key is now invalid */
 923         spin_lock(&wdm_device_list_lock);
 924         list_del(&desc->device_list);
 925         spin_unlock(&wdm_device_list_lock);
 926
 927         if (!desc->count)
 928                 cleanup(desc);
 929         else
 930                 dev_dbg(&intf->dev, "%s: %d open files - postponing cleanup\n", __func__, desc->count);
 931         mutex_unlock(&wdm_mutex);
 932 }
 933
 934 #ifdef CONFIG_PM
 935 static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
 936 {
 937         struct wdm_device *desc = wdm_find_device(intf);
 938         int rv = 0;
 939
 940         dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
 941
 942         /* if this is an autosuspend the caller does the locking */
 943         if (!PMSG_IS_AUTO(message)) {
 944                 mutex_lock(&desc->rlock);
 945                 mutex_lock(&desc->wlock);
 946         }
 947         spin_lock_irq(&desc->iuspin);
 948
 949         if (PMSG_IS_AUTO(message) &&
 950                         (test_bit(WDM_IN_USE, &desc->flags)
 951                         || test_bit(WDM_RESPONDING, &desc->flags))) {
 952                 spin_unlock_irq(&desc->iuspin);
 953                 rv = -EBUSY;
 954         } else {
 955
 956                 set_bit(WDM_SUSPENDING, &desc->flags);
 957                 spin_unlock_irq(&desc->iuspin);
 958                 /* callback submits work - order is essential */
 959                 kill_urbs(desc);
 960                 cancel_work_sync(&desc->rxwork);
 961         }
 962         if (!PMSG_IS_AUTO(message)) {
 963                 mutex_unlock(&desc->wlock);
 964                 mutex_unlock(&desc->rlock);
 965         }
 966
 967         return rv;
 968 }
 969 #endif
 970
 971 static int recover_from_urb_loss(struct wdm_device *desc)
 972 {
 973         int rv = 0;
 974
 975         if (desc->count) {
 976                 rv = usb_submit_urb(desc->validity, GFP_NOIO);
 977                 if (rv < 0)
 978                         dev_err(&desc->intf->dev,
 979                                 "Error resume submitting int urb - %d\n", rv);
 980         }
 981         return rv;
 982 }
 983
 984 #ifdef CONFIG_PM
 985 static int wdm_resume(struct usb_interface *intf)
 986 {
 987         struct wdm_device *desc = wdm_find_device(intf);
 988         int rv;
 989
 990         dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
 991
 992         clear_bit(WDM_SUSPENDING, &desc->flags);
 993         rv = recover_from_urb_loss(desc);
 994
 995         return rv;
 996 }
 997 #endif
 998
 999 static int wdm_pre_reset(struct usb_interface *intf)
1000 {
1001         struct wdm_device *desc = wdm_find_device(intf);
1002
1003         /*
1004          * we notify everybody using poll of
1005          * an exceptional situation
1006          * must be done before recovery lest a spontaneous
1007          * message from the device is lost
1008          */
1009         spin_lock_irq(&desc->iuspin);
1010         set_bit(WDM_RESETTING, &desc->flags);   /* inform read/write */
1011         set_bit(WDM_READ, &desc->flags);        /* unblock read */
1012         clear_bit(WDM_IN_USE, &desc->flags);    /* unblock write */
1013         desc->rerr = -EINTR;
1014         spin_unlock_irq(&desc->iuspin);
1015         wake_up_all(&desc->wait);
1016         mutex_lock(&desc->rlock);
1017         mutex_lock(&desc->wlock);
1018         kill_urbs(desc);
1019         cancel_work_sync(&desc->rxwork);
1020         return 0;
1021 }
1022
1023 static int wdm_post_reset(struct usb_interface *intf)
1024 {
1025         struct wdm_device *desc = wdm_find_device(intf);
1026         int rv;
1027
1028         clear_bit(WDM_RESETTING, &desc->flags);
1029         rv = recover_from_urb_loss(desc);
1030         mutex_unlock(&desc->wlock);
1031         mutex_unlock(&desc->rlock);
1032         return 0;
1033 }
1034
1035 static struct usb_driver wdm_driver = {
1036         .name =         "cdc_wdm",
1037         .probe =        wdm_probe,
1038         .disconnect =   wdm_disconnect,
1039 #ifdef CONFIG_PM
1040         .suspend =      wdm_suspend,
1041         .resume =       wdm_resume,
1042         .reset_resume = wdm_resume,
1043 #endif
1044         .pre_reset =    wdm_pre_reset,
1045         .post_reset =   wdm_post_reset,
1046         .id_table =     wdm_ids,
1047         .supports_autosuspend = 1,
1048         .disable_hub_initiated_lpm = 1,
1049 };
1050
1051 module_usb_driver(wdm_driver);
1052
1053 MODULE_AUTHOR(DRIVER_AUTHOR);
1054 MODULE_DESCRIPTION(DRIVER_DESC);
1055 MODULE_LICENSE("GPL");