drivers/usb/class/cdc-wdm.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * cdc-wdm.c
   4  *
   5  * This driver supports USB CDC WCM Device Management.
   6  *
   7  * Copyright (c) 2007-2009 Oliver Neukum
   8  *
   9  * Some code taken from cdc-acm.c
  10  *
  11  * Released under the GPLv2.
  12  *
  13  * Many thanks to Carl Nordbeck
  14  */
  15 #include <linux/kernel.h>
  16 #include <linux/errno.h>
  17 #include <linux/ioctl.h>
  18 #include <linux/slab.h>
  19 #include <linux/module.h>
  20 #include <linux/mutex.h>
  21 #include <linux/uaccess.h>
  22 #include <linux/bitops.h>
  23 #include <linux/poll.h>
  24 #include <linux/usb.h>
  25 #include <linux/usb/cdc.h>
  26 #include <asm/byteorder.h>
  27 #include <asm/unaligned.h>
  28 #include <linux/usb/cdc-wdm.h>
  29
  30 #define DRIVER_AUTHOR "Oliver Neukum"
  31 #define DRIVER_DESC "USB Abstract Control Model driver for USB WCM Device Management"
  32
  33 static const struct usb_device_id wdm_ids[] = {
  34         {
  35                 .match_flags = USB_DEVICE_ID_MATCH_INT_CLASS |
  36                                  USB_DEVICE_ID_MATCH_INT_SUBCLASS,
  37                 .bInterfaceClass = USB_CLASS_COMM,
  38                 .bInterfaceSubClass = USB_CDC_SUBCLASS_DMM
  39         },
  40         { }
  41 };
  42
  43 MODULE_DEVICE_TABLE (usb, wdm_ids);
  44
  45 #define WDM_MINOR_BASE  176
  46
  47
  48 #define WDM_IN_USE              1
  49 #define WDM_DISCONNECTING       2
  50 #define WDM_RESULT              3
  51 #define WDM_READ                4
  52 #define WDM_INT_STALL           5
  53 #define WDM_POLL_RUNNING        6
  54 #define WDM_RESPONDING          7
  55 #define WDM_SUSPENDING          8
  56 #define WDM_RESETTING           9
  57 #define WDM_OVERFLOW            10
  58
  59 #define WDM_MAX                 16
  60
  61 /* we cannot wait forever at flush() */
  62 #define WDM_FLUSH_TIMEOUT       (30 * HZ)
  63
  64 /* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */
  65 #define WDM_DEFAULT_BUFSIZE     256
  66
  67 static DEFINE_MUTEX(wdm_mutex);
  68 static DEFINE_SPINLOCK(wdm_device_list_lock);
  69 static LIST_HEAD(wdm_device_list);
  70
  71 /* --- method tables --- */
  72
  73 struct wdm_device {
  74         u8                      *inbuf; /* buffer for response */
  75         u8                      *outbuf; /* buffer for command */
  76         u8                      *sbuf; /* buffer for status */
  77         u8                      *ubuf; /* buffer for copy to user space */
  78
  79         struct urb              *command;
  80         struct urb              *response;
  81         struct urb              *validity;
  82         struct usb_interface    *intf;
  83         struct usb_ctrlrequest  *orq;
  84         struct usb_ctrlrequest  *irq;
  85         spinlock_t              iuspin;
  86
  87         unsigned long           flags;
  88         u16                     bufsize;
  89         u16                     wMaxCommand;
  90         u16                     wMaxPacketSize;
  91         __le16                  inum;
  92         int                     reslength;
  93         int                     length;
  94         int                     read;
  95         int                     count;
  96         dma_addr_t              shandle;
  97         dma_addr_t              ihandle;
  98         struct mutex            wlock;
  99         struct mutex            rlock;
 100         wait_queue_head_t       wait;
 101         struct work_struct      rxwork;
 102         struct work_struct      service_outs_intr;
 103         int                     werr;
 104         int                     rerr;
 105         int                     resp_count;
 106
 107         struct list_head        device_list;
 108         int                     (*manage_power)(struct usb_interface *, int);
 109 };
 110
 111 static struct usb_driver wdm_driver;
 112
 113 /* return intfdata if we own the interface, else look up intf in the list */
 114 static struct wdm_device *wdm_find_device(struct usb_interface *intf)
 115 {
 116         struct wdm_device *desc;
 117
 118         spin_lock(&wdm_device_list_lock);
 119         list_for_each_entry(desc, &wdm_device_list, device_list)
 120                 if (desc->intf == intf)
 121                         goto found;
 122         desc = NULL;
 123 found:
 124         spin_unlock(&wdm_device_list_lock);
 125
 126         return desc;
 127 }
 128
 129 static struct wdm_device *wdm_find_device_by_minor(int minor)
 130 {
 131         struct wdm_device *desc;
 132
 133         spin_lock(&wdm_device_list_lock);
 134         list_for_each_entry(desc, &wdm_device_list, device_list)
 135                 if (desc->intf->minor == minor)
 136                         goto found;
 137         desc = NULL;
 138 found:
 139         spin_unlock(&wdm_device_list_lock);
 140
 141         return desc;
 142 }
 143
 144 /* --- callbacks --- */
 145 static void wdm_out_callback(struct urb *urb)
 146 {
 147         struct wdm_device *desc;
 148         unsigned long flags;
 149
 150         desc = urb->context;
 151         spin_lock_irqsave(&desc->iuspin, flags);
 152         desc->werr = urb->status;
 153         spin_unlock_irqrestore(&desc->iuspin, flags);
 154         kfree(desc->outbuf);
 155         desc->outbuf = NULL;
 156         clear_bit(WDM_IN_USE, &desc->flags);
 157         wake_up_all(&desc->wait);
 158 }
 159
 160 static void wdm_in_callback(struct urb *urb)
 161 {
 162         unsigned long flags;
 163         struct wdm_device *desc = urb->context;
 164         int status = urb->status;
 165         int length = urb->actual_length;
 166
 167         spin_lock_irqsave(&desc->iuspin, flags);
 168         clear_bit(WDM_RESPONDING, &desc->flags);
 169
 170         if (status) {
 171                 switch (status) {
 172                 case -ENOENT:
 173                         dev_dbg(&desc->intf->dev,
 174                                 "nonzero urb status received: -ENOENT\n");
 175                         goto skip_error;
 176                 case -ECONNRESET:
 177                         dev_dbg(&desc->intf->dev,
 178                                 "nonzero urb status received: -ECONNRESET\n");
 179                         goto skip_error;
 180                 case -ESHUTDOWN:
 181                         dev_dbg(&desc->intf->dev,
 182                                 "nonzero urb status received: -ESHUTDOWN\n");
 183                         goto skip_error;
 184                 case -EPIPE:
 185                         dev_err(&desc->intf->dev,
 186                                 "nonzero urb status received: -EPIPE\n");
 187                         break;
 188                 default:
 189                         dev_err(&desc->intf->dev,
 190                                 "Unexpected error %d\n", status);
 191                         break;
 192                 }
 193         }
 194
 195         /*
 196          * only set a new error if there is no previous error.
 197          * Errors are only cleared during read/open
 198          * Avoid propagating -EPIPE (stall) to userspace since it is
 199          * better handled as an empty read
 200          */
 201         if (desc->rerr == 0 && status != -EPIPE)
 202                 desc->rerr = status;
 203
 204         if (length + desc->length > desc->wMaxCommand) {
 205                 /* The buffer would overflow */
 206                 set_bit(WDM_OVERFLOW, &desc->flags);
 207         } else {
 208                 /* we may already be in overflow */
 209                 if (!test_bit(WDM_OVERFLOW, &desc->flags)) {
 210                         memmove(desc->ubuf + desc->length, desc->inbuf, length);
 211                         desc->length += length;
 212                         desc->reslength = length;
 213                 }
 214         }
 215 skip_error:
 216
 217         if (desc->rerr) {
 218                 /*
 219                  * Since there was an error, userspace may decide to not read
 220                  * any data after poll'ing.
 221                  * We should respond to further attempts from the device to send
 222                  * data, so that we can get unstuck.
 223                  */
 224                 schedule_work(&desc->service_outs_intr);
 225         } else {
 226                 set_bit(WDM_READ, &desc->flags);
 227                 wake_up(&desc->wait);
 228         }
 229         spin_unlock_irqrestore(&desc->iuspin, flags);
 230 }
 231
 232 static void wdm_int_callback(struct urb *urb)
 233 {
 234         unsigned long flags;
 235         int rv = 0;
 236         int responding;
 237         int status = urb->status;
 238         struct wdm_device *desc;
 239         struct usb_cdc_notification *dr;
 240
 241         desc = urb->context;
 242         dr = (struct usb_cdc_notification *)desc->sbuf;
 243
 244         if (status) {
 245                 switch (status) {
 246                 case -ESHUTDOWN:
 247                 case -ENOENT:
 248                 case -ECONNRESET:
 249                         return; /* unplug */
 250                 case -EPIPE:
 251                         set_bit(WDM_INT_STALL, &desc->flags);
 252                         dev_err(&desc->intf->dev, "Stall on int endpoint\n");
 253                         goto sw; /* halt is cleared in work */
 254                 default:
 255                         dev_err(&desc->intf->dev,
 256                                 "nonzero urb status received: %d\n", status);
 257                         break;
 258                 }
 259         }
 260
 261         if (urb->actual_length < sizeof(struct usb_cdc_notification)) {
 262                 dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n",
 263                         urb->actual_length);
 264                 goto exit;
 265         }
 266
 267         switch (dr->bNotificationType) {
 268         case USB_CDC_NOTIFY_RESPONSE_AVAILABLE:
 269                 dev_dbg(&desc->intf->dev,
 270                         "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d\n",
 271                         le16_to_cpu(dr->wIndex), le16_to_cpu(dr->wLength));
 272                 break;
 273
 274         case USB_CDC_NOTIFY_NETWORK_CONNECTION:
 275
 276                 dev_dbg(&desc->intf->dev,
 277                         "NOTIFY_NETWORK_CONNECTION %s network\n",
 278                         dr->wValue ? "connected to" : "disconnected from");
 279                 goto exit;
 280         case USB_CDC_NOTIFY_SPEED_CHANGE:
 281                 dev_dbg(&desc->intf->dev, "SPEED_CHANGE received (len %u)\n",
 282                         urb->actual_length);
 283                 goto exit;
 284         default:
 285                 clear_bit(WDM_POLL_RUNNING, &desc->flags);
 286                 dev_err(&desc->intf->dev,
 287                         "unknown notification %d received: index %d len %d\n",
 288                         dr->bNotificationType,
 289                         le16_to_cpu(dr->wIndex),
 290                         le16_to_cpu(dr->wLength));
 291                 goto exit;
 292         }
 293
 294         spin_lock_irqsave(&desc->iuspin, flags);
 295         responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
 296         if (!desc->resp_count++ && !responding
 297                 && !test_bit(WDM_DISCONNECTING, &desc->flags)
 298                 && !test_bit(WDM_SUSPENDING, &desc->flags)) {
 299                 rv = usb_submit_urb(desc->response, GFP_ATOMIC);
 300                 dev_dbg(&desc->intf->dev, "submit response URB %d\n", rv);
 301         }
 302         spin_unlock_irqrestore(&desc->iuspin, flags);
 303         if (rv < 0) {
 304                 clear_bit(WDM_RESPONDING, &desc->flags);
 305                 if (rv == -EPERM)
 306                         return;
 307                 if (rv == -ENOMEM) {
 308 sw:
 309                         rv = schedule_work(&desc->rxwork);
 310                         if (rv)
 311                                 dev_err(&desc->intf->dev,
 312                                         "Cannot schedule work\n");
 313                 }
 314         }
 315 exit:
 316         rv = usb_submit_urb(urb, GFP_ATOMIC);
 317         if (rv)
 318                 dev_err(&desc->intf->dev,
 319                         "%s - usb_submit_urb failed with result %d\n",
 320                         __func__, rv);
 321
 322 }
 323
 324 static void kill_urbs(struct wdm_device *desc)
 325 {
 326         /* the order here is essential */
 327         usb_kill_urb(desc->command);
 328         usb_kill_urb(desc->validity);
 329         usb_kill_urb(desc->response);
 330 }
 331
 332 static void free_urbs(struct wdm_device *desc)
 333 {
 334         usb_free_urb(desc->validity);
 335         usb_free_urb(desc->response);
 336         usb_free_urb(desc->command);
 337 }
 338
 339 static void cleanup(struct wdm_device *desc)
 340 {
 341         kfree(desc->sbuf);
 342         kfree(desc->inbuf);
 343         kfree(desc->orq);
 344         kfree(desc->irq);
 345         kfree(desc->ubuf);
 346         free_urbs(desc);
 347         kfree(desc);
 348 }
 349
 350 static ssize_t wdm_write
 351 (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 352 {
 353         u8 *buf;
 354         int rv = -EMSGSIZE, r, we;
 355         struct wdm_device *desc = file->private_data;
 356         struct usb_ctrlrequest *req;
 357
 358         if (count > desc->wMaxCommand)
 359                 count = desc->wMaxCommand;
 360
 361         spin_lock_irq(&desc->iuspin);
 362         we = desc->werr;
 363         desc->werr = 0;
 364         spin_unlock_irq(&desc->iuspin);
 365         if (we < 0)
 366                 return usb_translate_errors(we);
 367
 368         buf = memdup_user(buffer, count);
 369         if (IS_ERR(buf))
 370                 return PTR_ERR(buf);
 371
 372         /* concurrent writes and disconnect */
 373         r = mutex_lock_interruptible(&desc->wlock);
 374         rv = -ERESTARTSYS;
 375         if (r)
 376                 goto out_free_mem;
 377
 378         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 379                 rv = -ENODEV;
 380                 goto out_free_mem_lock;
 381         }
 382
 383         r = usb_autopm_get_interface(desc->intf);
 384         if (r < 0) {
 385                 rv = usb_translate_errors(r);
 386                 goto out_free_mem_lock;
 387         }
 388
 389         if (!(file->f_flags & O_NONBLOCK))
 390                 r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
 391                                                                 &desc->flags));
 392         else
 393                 if (test_bit(WDM_IN_USE, &desc->flags))
 394                         r = -EAGAIN;
 395
 396         if (test_bit(WDM_RESETTING, &desc->flags))
 397                 r = -EIO;
 398
 399         if (test_bit(WDM_DISCONNECTING, &desc->flags))
 400                 r = -ENODEV;
 401
 402         if (r < 0) {
 403                 rv = r;
 404                 goto out_free_mem_pm;
 405         }
 406
 407         req = desc->orq;
 408         usb_fill_control_urb(
 409                 desc->command,
 410                 interface_to_usbdev(desc->intf),
 411                 /* using common endpoint 0 */
 412                 usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
 413                 (unsigned char *)req,
 414                 buf,
 415                 count,
 416                 wdm_out_callback,
 417                 desc
 418         );
 419
 420         req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
 421                              USB_RECIP_INTERFACE);
 422         req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
 423         req->wValue = 0;
 424         req->wIndex = desc->inum; /* already converted */
 425         req->wLength = cpu_to_le16(count);
 426         set_bit(WDM_IN_USE, &desc->flags);
 427         desc->outbuf = buf;
 428
 429         rv = usb_submit_urb(desc->command, GFP_KERNEL);
 430         if (rv < 0) {
 431                 desc->outbuf = NULL;
 432                 clear_bit(WDM_IN_USE, &desc->flags);
 433                 wake_up_all(&desc->wait); /* for wdm_wait_for_response() */
 434                 dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
 435                 rv = usb_translate_errors(rv);
 436                 goto out_free_mem_pm;
 437         } else {
 438                 dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d\n",
 439                         le16_to_cpu(req->wIndex));
 440         }
 441
 442         usb_autopm_put_interface(desc->intf);
 443         mutex_unlock(&desc->wlock);
 444         return count;
 445
 446 out_free_mem_pm:
 447         usb_autopm_put_interface(desc->intf);
 448 out_free_mem_lock:
 449         mutex_unlock(&desc->wlock);
 450 out_free_mem:
 451         kfree(buf);
 452         return rv;
 453 }
 454
 455 /*
 456  * Submit the read urb if resp_count is non-zero.
 457  *
 458  * Called with desc->iuspin locked
 459  */
 460 static int service_outstanding_interrupt(struct wdm_device *desc)
 461 {
 462         int rv = 0;
 463
 464         /* submit read urb only if the device is waiting for it */
 465         if (!desc->resp_count || !--desc->resp_count)
 466                 goto out;
 467
 468         set_bit(WDM_RESPONDING, &desc->flags);
 469         spin_unlock_irq(&desc->iuspin);
 470         rv = usb_submit_urb(desc->response, GFP_KERNEL);
 471         spin_lock_irq(&desc->iuspin);
 472         if (rv) {
 473                 dev_err(&desc->intf->dev,
 474                         "usb_submit_urb failed with result %d\n", rv);
 475
 476                 /* make sure the next notification trigger a submit */
 477                 clear_bit(WDM_RESPONDING, &desc->flags);
 478                 desc->resp_count = 0;
 479         }
 480 out:
 481         return rv;
 482 }
 483
 484 static ssize_t wdm_read
 485 (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 486 {
 487         int rv, cntr;
 488         int i = 0;
 489         struct wdm_device *desc = file->private_data;
 490
 491
 492         rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
 493         if (rv < 0)
 494                 return -ERESTARTSYS;
 495
 496         cntr = READ_ONCE(desc->length);
 497         if (cntr == 0) {
 498                 desc->read = 0;
 499 retry:
 500                 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 501                         rv = -ENODEV;
 502                         goto err;
 503                 }
 504                 if (test_bit(WDM_OVERFLOW, &desc->flags)) {
 505                         clear_bit(WDM_OVERFLOW, &desc->flags);
 506                         rv = -ENOBUFS;
 507                         goto err;
 508                 }
 509                 i++;
 510                 if (file->f_flags & O_NONBLOCK) {
 511                         if (!test_bit(WDM_READ, &desc->flags)) {
 512                                 rv = -EAGAIN;
 513                                 goto err;
 514                         }
 515                         rv = 0;
 516                 } else {
 517                         rv = wait_event_interruptible(desc->wait,
 518                                 test_bit(WDM_READ, &desc->flags));
 519                 }
 520
 521                 /* may have happened while we slept */
 522                 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 523                         rv = -ENODEV;
 524                         goto err;
 525                 }
 526                 if (test_bit(WDM_RESETTING, &desc->flags)) {
 527                         rv = -EIO;
 528                         goto err;
 529                 }
 530                 usb_mark_last_busy(interface_to_usbdev(desc->intf));
 531                 if (rv < 0) {
 532                         rv = -ERESTARTSYS;
 533                         goto err;
 534                 }
 535
 536                 spin_lock_irq(&desc->iuspin);
 537
 538                 if (desc->rerr) { /* read completed, error happened */
 539                         rv = usb_translate_errors(desc->rerr);
 540                         desc->rerr = 0;
 541                         spin_unlock_irq(&desc->iuspin);
 542                         goto err;
 543                 }
 544                 /*
 545                  * recheck whether we've lost the race
 546                  * against the completion handler
 547                  */
 548                 if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */
 549                         spin_unlock_irq(&desc->iuspin);
 550                         goto retry;
 551                 }
 552
 553                 if (!desc->reslength) { /* zero length read */
 554                         dev_dbg(&desc->intf->dev, "zero length - clearing WDM_READ\n");
 555                         clear_bit(WDM_READ, &desc->flags);
 556                         rv = service_outstanding_interrupt(desc);
 557                         spin_unlock_irq(&desc->iuspin);
 558                         if (rv < 0)
 559                                 goto err;
 560                         goto retry;
 561                 }
 562                 cntr = desc->length;
 563                 spin_unlock_irq(&desc->iuspin);
 564         }
 565
 566         if (cntr > count)
 567                 cntr = count;
 568         rv = copy_to_user(buffer, desc->ubuf, cntr);
 569         if (rv > 0) {
 570                 rv = -EFAULT;
 571                 goto err;
 572         }
 573
 574         spin_lock_irq(&desc->iuspin);
 575
 576         for (i = 0; i < desc->length - cntr; i++)
 577                 desc->ubuf[i] = desc->ubuf[i + cntr];
 578
 579         desc->length -= cntr;
 580         /* in case we had outstanding data */
 581         if (!desc->length) {
 582                 clear_bit(WDM_READ, &desc->flags);
 583                 service_outstanding_interrupt(desc);
 584         }
 585         spin_unlock_irq(&desc->iuspin);
 586         rv = cntr;
 587
 588 err:
 589         mutex_unlock(&desc->rlock);
 590         return rv;
 591 }
 592
 593 static int wdm_wait_for_response(struct file *file, long timeout)
 594 {
 595         struct wdm_device *desc = file->private_data;
 596         long rv; /* Use long here because (int) MAX_SCHEDULE_TIMEOUT < 0. */
 597
 598         /*
 599          * Needs both flags. We cannot do with one because resetting it would
 600          * cause a race with write() yet we need to signal a disconnect.
 601          */
 602         rv = wait_event_interruptible_timeout(desc->wait,
 603                               !test_bit(WDM_IN_USE, &desc->flags) ||
 604                               test_bit(WDM_DISCONNECTING, &desc->flags),
 605                               timeout);
 606
 607         /*
 608          * To report the correct error. This is best effort.
 609          * We are inevitably racing with the hardware.
 610          */
 611         if (test_bit(WDM_DISCONNECTING, &desc->flags))
 612                 return -ENODEV;
 613         if (!rv)
 614                 return -EIO;
 615         if (rv < 0)
 616                 return -EINTR;
 617
 618         spin_lock_irq(&desc->iuspin);
 619         rv = desc->werr;
 620         desc->werr = 0;
 621         spin_unlock_irq(&desc->iuspin);
 622
 623         return usb_translate_errors(rv);
 624
 625 }
 626
 627 /*
 628  * You need to send a signal when you react to malicious or defective hardware.
 629  * Also, don't abort when fsync() returned -EINVAL, for older kernels which do
 630  * not implement wdm_flush() will return -EINVAL.
 631  */
 632 static int wdm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 633 {
 634         return wdm_wait_for_response(file, MAX_SCHEDULE_TIMEOUT);
 635 }
 636
 637 /*
 638  * Same with wdm_fsync(), except it uses finite timeout in order to react to
 639  * malicious or defective hardware which ceased communication after close() was
 640  * implicitly called due to process termination.
 641  */
 642 static int wdm_flush(struct file *file, fl_owner_t id)
 643 {
 644         return wdm_wait_for_response(file, WDM_FLUSH_TIMEOUT);
 645 }
 646
 647 static __poll_t wdm_poll(struct file *file, struct poll_table_struct *wait)
 648 {
 649         struct wdm_device *desc = file->private_data;
 650         unsigned long flags;
 651         __poll_t mask = 0;
 652
 653         spin_lock_irqsave(&desc->iuspin, flags);
 654         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 655                 mask = EPOLLHUP | EPOLLERR;
 656                 spin_unlock_irqrestore(&desc->iuspin, flags);
 657                 goto desc_out;
 658         }
 659         if (test_bit(WDM_READ, &desc->flags))
 660                 mask = EPOLLIN | EPOLLRDNORM;
 661         if (desc->rerr || desc->werr)
 662                 mask |= EPOLLERR;
 663         if (!test_bit(WDM_IN_USE, &desc->flags))
 664                 mask |= EPOLLOUT | EPOLLWRNORM;
 665         spin_unlock_irqrestore(&desc->iuspin, flags);
 666
 667         poll_wait(file, &desc->wait, wait);
 668
 669 desc_out:
 670         return mask;
 671 }
 672
 673 static int wdm_open(struct inode *inode, struct file *file)
 674 {
 675         int minor = iminor(inode);
 676         int rv = -ENODEV;
 677         struct usb_interface *intf;
 678         struct wdm_device *desc;
 679
 680         mutex_lock(&wdm_mutex);
 681         desc = wdm_find_device_by_minor(minor);
 682         if (!desc)
 683                 goto out;
 684
 685         intf = desc->intf;
 686         if (test_bit(WDM_DISCONNECTING, &desc->flags))
 687                 goto out;
 688         file->private_data = desc;
 689
 690         rv = usb_autopm_get_interface(desc->intf);
 691         if (rv < 0) {
 692                 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
 693                 goto out;
 694         }
 695
 696         /* using write lock to protect desc->count */
 697         mutex_lock(&desc->wlock);
 698         if (!desc->count++) {
 699                 desc->werr = 0;
 700                 desc->rerr = 0;
 701                 rv = usb_submit_urb(desc->validity, GFP_KERNEL);
 702                 if (rv < 0) {
 703                         desc->count--;
 704                         dev_err(&desc->intf->dev,
 705                                 "Error submitting int urb - %d\n", rv);
 706                         rv = usb_translate_errors(rv);
 707                 }
 708         } else {
 709                 rv = 0;
 710         }
 711         mutex_unlock(&desc->wlock);
 712         if (desc->count == 1)
 713                 desc->manage_power(intf, 1);
 714         usb_autopm_put_interface(desc->intf);
 715 out:
 716         mutex_unlock(&wdm_mutex);
 717         return rv;
 718 }
 719
 720 static int wdm_release(struct inode *inode, struct file *file)
 721 {
 722         struct wdm_device *desc = file->private_data;
 723
 724         mutex_lock(&wdm_mutex);
 725
 726         /* using write lock to protect desc->count */
 727         mutex_lock(&desc->wlock);
 728         desc->count--;
 729         mutex_unlock(&desc->wlock);
 730
 731         if (!desc->count) {
 732                 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
 733                         dev_dbg(&desc->intf->dev, "wdm_release: cleanup\n");
 734                         kill_urbs(desc);
 735                         spin_lock_irq(&desc->iuspin);
 736                         desc->resp_count = 0;
 737                         spin_unlock_irq(&desc->iuspin);
 738                         desc->manage_power(desc->intf, 0);
 739                 } else {
 740                         /* must avoid dev_printk here as desc->intf is invalid */
 741                         pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
 742                         cleanup(desc);
 743                 }
 744         }
 745         mutex_unlock(&wdm_mutex);
 746         return 0;
 747 }
 748
 749 static long wdm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 750 {
 751         struct wdm_device *desc = file->private_data;
 752         int rv = 0;
 753
 754         switch (cmd) {
 755         case IOCTL_WDM_MAX_COMMAND:
 756                 if (copy_to_user((void __user *)arg, &desc->wMaxCommand, sizeof(desc->wMaxCommand)))
 757                         rv = -EFAULT;
 758                 break;
 759         default:
 760                 rv = -ENOTTY;
 761         }
 762         return rv;
 763 }
 764
 765 static const struct file_operations wdm_fops = {
 766         .owner =        THIS_MODULE,
 767         .read =         wdm_read,
 768         .write =        wdm_write,
 769         .fsync =        wdm_fsync,
 770         .open =         wdm_open,
 771         .flush =        wdm_flush,
 772         .release =      wdm_release,
 773         .poll =         wdm_poll,
 774         .unlocked_ioctl = wdm_ioctl,
 775         .compat_ioctl = compat_ptr_ioctl,
 776         .llseek =       noop_llseek,
 777 };
 778
 779 static struct usb_class_driver wdm_class = {
 780         .name =         "cdc-wdm%d",
 781         .fops =         &wdm_fops,
 782         .minor_base =   WDM_MINOR_BASE,
 783 };
 784
 785 /* --- error handling --- */
 786 static void wdm_rxwork(struct work_struct *work)
 787 {
 788         struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
 789         unsigned long flags;
 790         int rv = 0;
 791         int responding;
 792
 793         spin_lock_irqsave(&desc->iuspin, flags);
 794         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
 795                 spin_unlock_irqrestore(&desc->iuspin, flags);
 796         } else {
 797                 responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
 798                 spin_unlock_irqrestore(&desc->iuspin, flags);
 799                 if (!responding)
 800                         rv = usb_submit_urb(desc->response, GFP_KERNEL);
 801                 if (rv < 0 && rv != -EPERM) {
 802                         spin_lock_irqsave(&desc->iuspin, flags);
 803                         clear_bit(WDM_RESPONDING, &desc->flags);
 804                         if (!test_bit(WDM_DISCONNECTING, &desc->flags))
 805                                 schedule_work(&desc->rxwork);
 806                         spin_unlock_irqrestore(&desc->iuspin, flags);
 807                 }
 808         }
 809 }
 810
 811 static void service_interrupt_work(struct work_struct *work)
 812 {
 813         struct wdm_device *desc;
 814
 815         desc = container_of(work, struct wdm_device, service_outs_intr);
 816
 817         spin_lock_irq(&desc->iuspin);
 818         service_outstanding_interrupt(desc);
 819         if (!desc->resp_count) {
 820                 set_bit(WDM_READ, &desc->flags);
 821                 wake_up(&desc->wait);
 822         }
 823         spin_unlock_irq(&desc->iuspin);
 824 }
 825
 826 /* --- hotplug --- */
 827
 828 static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
 829                 u16 bufsize, int (*manage_power)(struct usb_interface *, int))
 830 {
 831         int rv = -ENOMEM;
 832         struct wdm_device *desc;
 833
 834         desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
 835         if (!desc)
 836                 goto out;
 837         INIT_LIST_HEAD(&desc->device_list);
 838         mutex_init(&desc->rlock);
 839         mutex_init(&desc->wlock);
 840         spin_lock_init(&desc->iuspin);
 841         init_waitqueue_head(&desc->wait);
 842         desc->wMaxCommand = bufsize;
 843         /* this will be expanded and needed in hardware endianness */
 844         desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
 845         desc->intf = intf;
 846         INIT_WORK(&desc->rxwork, wdm_rxwork);
 847         INIT_WORK(&desc->service_outs_intr, service_interrupt_work);
 848
 849         rv = -EINVAL;
 850         if (!usb_endpoint_is_int_in(ep))
 851                 goto err;
 852
 853         desc->wMaxPacketSize = usb_endpoint_maxp(ep);
 854
 855         desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
 856         if (!desc->orq)
 857                 goto err;
 858         desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
 859         if (!desc->irq)
 860                 goto err;
 861
 862         desc->validity = usb_alloc_urb(0, GFP_KERNEL);
 863         if (!desc->validity)
 864                 goto err;
 865
 866         desc->response = usb_alloc_urb(0, GFP_KERNEL);
 867         if (!desc->response)
 868                 goto err;
 869
 870         desc->command = usb_alloc_urb(0, GFP_KERNEL);
 871         if (!desc->command)
 872                 goto err;
 873
 874         desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
 875         if (!desc->ubuf)
 876                 goto err;
 877
 878         desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);
 879         if (!desc->sbuf)
 880                 goto err;
 881
 882         desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
 883         if (!desc->inbuf)
 884                 goto err;
 885
 886         usb_fill_int_urb(
 887                 desc->validity,
 888                 interface_to_usbdev(intf),
 889                 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
 890                 desc->sbuf,
 891                 desc->wMaxPacketSize,
 892                 wdm_int_callback,
 893                 desc,
 894                 ep->bInterval
 895         );
 896
 897         desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
 898         desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
 899         desc->irq->wValue = 0;
 900         desc->irq->wIndex = desc->inum; /* already converted */
 901         desc->irq->wLength = cpu_to_le16(desc->wMaxCommand);
 902
 903         usb_fill_control_urb(
 904                 desc->response,
 905                 interface_to_usbdev(intf),
 906                 /* using common endpoint 0 */
 907                 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
 908                 (unsigned char *)desc->irq,
 909                 desc->inbuf,
 910                 desc->wMaxCommand,
 911                 wdm_in_callback,
 912                 desc
 913         );
 914
 915         desc->manage_power = manage_power;
 916
 917         spin_lock(&wdm_device_list_lock);
 918         list_add(&desc->device_list, &wdm_device_list);
 919         spin_unlock(&wdm_device_list_lock);
 920
 921         rv = usb_register_dev(intf, &wdm_class);
 922         if (rv < 0)
 923                 goto err;
 924         else
 925                 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev));
 926 out:
 927         return rv;
 928 err:
 929         spin_lock(&wdm_device_list_lock);
 930         list_del(&desc->device_list);
 931         spin_unlock(&wdm_device_list_lock);
 932         cleanup(desc);
 933         return rv;
 934 }
 935
 936 static int wdm_manage_power(struct usb_interface *intf, int on)
 937 {
 938         /* need autopm_get/put here to ensure the usbcore sees the new value */
 939         int rv = usb_autopm_get_interface(intf);
 940
 941         intf->needs_remote_wakeup = on;
 942         if (!rv)
 943                 usb_autopm_put_interface(intf);
 944         return 0;
 945 }
 946
 947 static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
 948 {
 949         int rv = -EINVAL;
 950         struct usb_host_interface *iface;
 951         struct usb_endpoint_descriptor *ep;
 952         struct usb_cdc_parsed_header hdr;
 953         u8 *buffer = intf->altsetting->extra;
 954         int buflen = intf->altsetting->extralen;
 955         u16 maxcom = WDM_DEFAULT_BUFSIZE;
 956
 957         if (!buffer)
 958                 goto err;
 959
 960         cdc_parse_cdc_header(&hdr, intf, buffer, buflen);
 961
 962         if (hdr.usb_cdc_dmm_desc)
 963                 maxcom = le16_to_cpu(hdr.usb_cdc_dmm_desc->wMaxCommand);
 964
 965         iface = intf->cur_altsetting;
 966         if (iface->desc.bNumEndpoints != 1)
 967                 goto err;
 968         ep = &iface->endpoint[0].desc;
 969
 970         rv = wdm_create(intf, ep, maxcom, &wdm_manage_power);
 971
 972 err:
 973         return rv;
 974 }
 975
 976 /**
 977  * usb_cdc_wdm_register - register a WDM subdriver
 978  * @intf: usb interface the subdriver will associate with
 979  * @ep: interrupt endpoint to monitor for notifications
 980  * @bufsize: maximum message size to support for read/write
 981  * @manage_power: call-back invoked during open and release to
 982  *                manage the device's power
 983  * Create WDM usb class character device and associate it with intf
 984  * without binding, allowing another driver to manage the interface.
 985  *
 986  * The subdriver will manage the given interrupt endpoint exclusively
 987  * and will issue control requests referring to the given intf. It
 988  * will otherwise avoid interferring, and in particular not do
 989  * usb_set_intfdata/usb_get_intfdata on intf.
 990  *
 991  * The return value is a pointer to the subdriver's struct usb_driver.
 992  * The registering driver is responsible for calling this subdriver's
 993  * disconnect, suspend, resume, pre_reset and post_reset methods from
 994  * its own.
 995  */
 996 struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,
 997                                         struct usb_endpoint_descriptor *ep,
 998                                         int bufsize,
 999                                         int (*manage_power)(struct usb_interface *, int))
1000 {
1001         int rv;
1002
1003         rv = wdm_create(intf, ep, bufsize, manage_power);
1004         if (rv < 0)
1005                 goto err;
1006
1007         return &wdm_driver;
1008 err:
1009         return ERR_PTR(rv);
1010 }
1011 EXPORT_SYMBOL(usb_cdc_wdm_register);
1012
1013 static void wdm_disconnect(struct usb_interface *intf)
1014 {
1015         struct wdm_device *desc;
1016         unsigned long flags;
1017
1018         usb_deregister_dev(intf, &wdm_class);
1019         desc = wdm_find_device(intf);
1020         mutex_lock(&wdm_mutex);
1021
1022         /* the spinlock makes sure no new urbs are generated in the callbacks */
1023         spin_lock_irqsave(&desc->iuspin, flags);
1024         set_bit(WDM_DISCONNECTING, &desc->flags);
1025         set_bit(WDM_READ, &desc->flags);
1026         spin_unlock_irqrestore(&desc->iuspin, flags);
1027         wake_up_all(&desc->wait);
1028         mutex_lock(&desc->rlock);
1029         mutex_lock(&desc->wlock);
1030         kill_urbs(desc);
1031         cancel_work_sync(&desc->rxwork);
1032         cancel_work_sync(&desc->service_outs_intr);
1033         mutex_unlock(&desc->wlock);
1034         mutex_unlock(&desc->rlock);
1035
1036         /* the desc->intf pointer used as list key is now invalid */
1037         spin_lock(&wdm_device_list_lock);
1038         list_del(&desc->device_list);
1039         spin_unlock(&wdm_device_list_lock);
1040
1041         if (!desc->count)
1042                 cleanup(desc);
1043         else
1044                 dev_dbg(&intf->dev, "%d open files - postponing cleanup\n", desc->count);
1045         mutex_unlock(&wdm_mutex);
1046 }
1047
1048 #ifdef CONFIG_PM
1049 static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
1050 {
1051         struct wdm_device *desc = wdm_find_device(intf);
1052         int rv = 0;
1053
1054         dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
1055
1056         /* if this is an autosuspend the caller does the locking */
1057         if (!PMSG_IS_AUTO(message)) {
1058                 mutex_lock(&desc->rlock);
1059                 mutex_lock(&desc->wlock);
1060         }
1061         spin_lock_irq(&desc->iuspin);
1062
1063         if (PMSG_IS_AUTO(message) &&
1064                         (test_bit(WDM_IN_USE, &desc->flags)
1065                         || test_bit(WDM_RESPONDING, &desc->flags))) {
1066                 spin_unlock_irq(&desc->iuspin);
1067                 rv = -EBUSY;
1068         } else {
1069
1070                 set_bit(WDM_SUSPENDING, &desc->flags);
1071                 spin_unlock_irq(&desc->iuspin);
1072                 /* callback submits work - order is essential */
1073                 kill_urbs(desc);
1074                 cancel_work_sync(&desc->rxwork);
1075                 cancel_work_sync(&desc->service_outs_intr);
1076         }
1077         if (!PMSG_IS_AUTO(message)) {
1078                 mutex_unlock(&desc->wlock);
1079                 mutex_unlock(&desc->rlock);
1080         }
1081
1082         return rv;
1083 }
1084 #endif
1085
1086 static int recover_from_urb_loss(struct wdm_device *desc)
1087 {
1088         int rv = 0;
1089
1090         if (desc->count) {
1091                 rv = usb_submit_urb(desc->validity, GFP_NOIO);
1092                 if (rv < 0)
1093                         dev_err(&desc->intf->dev,
1094                                 "Error resume submitting int urb - %d\n", rv);
1095         }
1096         return rv;
1097 }
1098
1099 #ifdef CONFIG_PM
1100 static int wdm_resume(struct usb_interface *intf)
1101 {
1102         struct wdm_device *desc = wdm_find_device(intf);
1103         int rv;
1104
1105         dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
1106
1107         clear_bit(WDM_SUSPENDING, &desc->flags);
1108         rv = recover_from_urb_loss(desc);
1109
1110         return rv;
1111 }
1112 #endif
1113
1114 static int wdm_pre_reset(struct usb_interface *intf)
1115 {
1116         struct wdm_device *desc = wdm_find_device(intf);
1117
1118         /*
1119          * we notify everybody using poll of
1120          * an exceptional situation
1121          * must be done before recovery lest a spontaneous
1122          * message from the device is lost
1123          */
1124         spin_lock_irq(&desc->iuspin);
1125         set_bit(WDM_RESETTING, &desc->flags);   /* inform read/write */
1126         set_bit(WDM_READ, &desc->flags);        /* unblock read */
1127         clear_bit(WDM_IN_USE, &desc->flags);    /* unblock write */
1128         desc->rerr = -EINTR;
1129         spin_unlock_irq(&desc->iuspin);
1130         wake_up_all(&desc->wait);
1131         mutex_lock(&desc->rlock);
1132         mutex_lock(&desc->wlock);
1133         kill_urbs(desc);
1134         cancel_work_sync(&desc->rxwork);
1135         cancel_work_sync(&desc->service_outs_intr);
1136         return 0;
1137 }
1138
1139 static int wdm_post_reset(struct usb_interface *intf)
1140 {
1141         struct wdm_device *desc = wdm_find_device(intf);
1142         int rv;
1143
1144         clear_bit(WDM_OVERFLOW, &desc->flags);
1145         clear_bit(WDM_RESETTING, &desc->flags);
1146         rv = recover_from_urb_loss(desc);
1147         mutex_unlock(&desc->wlock);
1148         mutex_unlock(&desc->rlock);
1149         return rv;
1150 }
1151
1152 static struct usb_driver wdm_driver = {
1153         .name =         "cdc_wdm",
1154         .probe =        wdm_probe,
1155         .disconnect =   wdm_disconnect,
1156 #ifdef CONFIG_PM
1157         .suspend =      wdm_suspend,
1158         .resume =       wdm_resume,
1159         .reset_resume = wdm_resume,
1160 #endif
1161         .pre_reset =    wdm_pre_reset,
1162         .post_reset =   wdm_post_reset,
1163         .id_table =     wdm_ids,
1164         .supports_autosuspend = 1,
1165         .disable_hub_initiated_lpm = 1,
1166 };
1167
1168 module_usb_driver(wdm_driver);
1169
1170 MODULE_AUTHOR(DRIVER_AUTHOR);
1171 MODULE_DESCRIPTION(DRIVER_DESC);
1172 MODULE_LICENSE("GPL");