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