drivers/macintosh/adb.c

   1 /*
   2  * Device driver for the Apple Desktop Bus
   3  * and the /dev/adb device on macintoshes.
   4  *
   5  * Copyright (C) 1996 Paul Mackerras.
   6  *
   7  * Modified to declare controllers as structures, added
   8  * client notification of bus reset and handles PowerBook
   9  * sleep, by Benjamin Herrenschmidt.
  10  *
  11  * To do:
  12  *
  13  * - /sys/bus/adb to list the devices and infos
  14  * - more /dev/adb to allow userland to receive the
  15  *   flow of auto-polling datas from a given device.
  16  * - move bus probe to a kernel thread
  17  */
  18
  19 #include <linux/types.h>
  20 #include <linux/errno.h>
  21 #include <linux/kernel.h>
  22 #include <linux/slab.h>
  23 #include <linux/module.h>
  24 #include <linux/fs.h>
  25 #include <linux/mm.h>
  26 #include <linux/sched.h>
  27 #include <linux/adb.h>
  28 #include <linux/cuda.h>
  29 #include <linux/pmu.h>
  30 #include <linux/notifier.h>
  31 #include <linux/wait.h>
  32 #include <linux/init.h>
  33 #include <linux/delay.h>
  34 #include <linux/spinlock.h>
  35 #include <linux/completion.h>
  36 #include <linux/device.h>
  37 #include <linux/kthread.h>
  38 #include <linux/platform_device.h>
  39 #include <linux/mutex.h>
  40
  41 #include <asm/uaccess.h>
  42 #ifdef CONFIG_PPC
  43 #include <asm/prom.h>
  44 #include <asm/machdep.h>
  45 #endif
  46
  47
  48 EXPORT_SYMBOL(adb_client_list);
  49
  50 extern struct adb_driver via_macii_driver;
  51 extern struct adb_driver via_maciisi_driver;
  52 extern struct adb_driver via_cuda_driver;
  53 extern struct adb_driver adb_iop_driver;
  54 extern struct adb_driver via_pmu_driver;
  55 extern struct adb_driver macio_adb_driver;
  56
  57 static DEFINE_MUTEX(adb_mutex);
  58 static struct adb_driver *adb_driver_list[] = {
  59 #ifdef CONFIG_ADB_MACII
  60         &via_macii_driver,
  61 #endif
  62 #ifdef CONFIG_ADB_MACIISI
  63         &via_maciisi_driver,
  64 #endif
  65 #ifdef CONFIG_ADB_CUDA
  66         &via_cuda_driver,
  67 #endif
  68 #ifdef CONFIG_ADB_IOP
  69         &adb_iop_driver,
  70 #endif
  71 #if defined(CONFIG_ADB_PMU) || defined(CONFIG_ADB_PMU68K)
  72         &via_pmu_driver,
  73 #endif
  74 #ifdef CONFIG_ADB_MACIO
  75         &macio_adb_driver,
  76 #endif
  77         NULL
  78 };
  79
  80 static struct class *adb_dev_class;
  81
  82 static struct adb_driver *adb_controller;
  83 BLOCKING_NOTIFIER_HEAD(adb_client_list);
  84 static int adb_got_sleep;
  85 static int adb_inited;
  86 static DEFINE_SEMAPHORE(adb_probe_mutex);
  87 static int sleepy_trackpad;
  88 static int autopoll_devs;
  89 int __adb_probe_sync;
  90
  91 static int adb_scan_bus(void);
  92 static int do_adb_reset_bus(void);
  93 static void adbdev_init(void);
  94 static int try_handler_change(int, int);
  95
  96 static struct adb_handler {
  97         void (*handler)(unsigned char *, int, int);
  98         int original_address;
  99         int handler_id;
 100         int busy;
 101 } adb_handler[16];
 102
 103 /*
 104  * The adb_handler_mutex mutex protects all accesses to the original_address
 105  * and handler_id fields of adb_handler[i] for all i, and changes to the
 106  * handler field.
 107  * Accesses to the handler field are protected by the adb_handler_lock
 108  * rwlock.  It is held across all calls to any handler, so that by the
 109  * time adb_unregister returns, we know that the old handler isn't being
 110  * called.
 111  */
 112 static DEFINE_MUTEX(adb_handler_mutex);
 113 static DEFINE_RWLOCK(adb_handler_lock);
 114
 115 #if 0
 116 static void printADBreply(struct adb_request *req)
 117 {
 118         int i;
 119
 120         printk("adb reply (%d)", req->reply_len);
 121         for(i = 0; i < req->reply_len; i++)
 122                 printk(" %x", req->reply[i]);
 123         printk("\n");
 124
 125 }
 126 #endif
 127
 128 static int adb_scan_bus(void)
 129 {
 130         int i, highFree=0, noMovement;
 131         int devmask = 0;
 132         struct adb_request req;
 133
 134         /* assumes adb_handler[] is all zeroes at this point */
 135         for (i = 1; i < 16; i++) {
 136                 /* see if there is anything at address i */
 137                 adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 138                             (i << 4) | 0xf);
 139                 if (req.reply_len > 1)
 140                         /* one or more devices at this address */
 141                         adb_handler[i].original_address = i;
 142                 else if (i > highFree)
 143                         highFree = i;
 144         }
 145
 146         /* Note we reset noMovement to 0 each time we move a device */
 147         for (noMovement = 1; noMovement < 2 && highFree > 0; noMovement++) {
 148                 for (i = 1; i < 16; i++) {
 149                         if (adb_handler[i].original_address == 0)
 150                                 continue;
 151                         /*
 152                          * Send a "talk register 3" command to address i
 153                          * to provoke a collision if there is more than
 154                          * one device at this address.
 155                          */
 156                         adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 157                                     (i << 4) | 0xf);
 158                         /*
 159                          * Move the device(s) which didn't detect a
 160                          * collision to address `highFree'.  Hopefully
 161                          * this only moves one device.
 162                          */
 163                         adb_request(&req, NULL, ADBREQ_SYNC, 3,
 164                                     (i<< 4) | 0xb, (highFree | 0x60), 0xfe);
 165                         /*
 166                          * See if anybody actually moved. This is suggested
 167                          * by HW TechNote 01:
 168                          *
 169                          * http://developer.apple.com/technotes/hw/hw_01.html
 170                          */
 171                         adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 172                                     (highFree << 4) | 0xf);
 173                         if (req.reply_len <= 1) continue;
 174                         /*
 175                          * Test whether there are any device(s) left
 176                          * at address i.
 177                          */
 178                         adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 179                                     (i << 4) | 0xf);
 180                         if (req.reply_len > 1) {
 181                                 /*
 182                                  * There are still one or more devices
 183                                  * left at address i.  Register the one(s)
 184                                  * we moved to `highFree', and find a new
 185                                  * value for highFree.
 186                                  */
 187                                 adb_handler[highFree].original_address =
 188                                         adb_handler[i].original_address;
 189                                 while (highFree > 0 &&
 190                                        adb_handler[highFree].original_address)
 191                                         highFree--;
 192                                 if (highFree <= 0)
 193                                         break;
 194
 195                                 noMovement = 0;
 196                         }
 197                         else {
 198                                 /*
 199                                  * No devices left at address i; move the
 200                                  * one(s) we moved to `highFree' back to i.
 201                                  */
 202                                 adb_request(&req, NULL, ADBREQ_SYNC, 3,
 203                                             (highFree << 4) | 0xb,
 204                                             (i | 0x60), 0xfe);
 205                         }
 206                 }
 207         }
 208
 209         /* Now fill in the handler_id field of the adb_handler entries. */
 210         printk(KERN_DEBUG "adb devices:");
 211         for (i = 1; i < 16; i++) {
 212                 if (adb_handler[i].original_address == 0)
 213                         continue;
 214                 adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 215                             (i << 4) | 0xf);
 216                 adb_handler[i].handler_id = req.reply[2];
 217                 printk(" [%d]: %d %x", i, adb_handler[i].original_address,
 218                        adb_handler[i].handler_id);
 219                 devmask |= 1 << i;
 220         }
 221         printk("\n");
 222         return devmask;
 223 }
 224
 225 /*
 226  * This kernel task handles ADB probing. It dies once probing is
 227  * completed.
 228  */
 229 static int
 230 adb_probe_task(void *x)
 231 {
 232         printk(KERN_INFO "adb: starting probe task...\n");
 233         do_adb_reset_bus();
 234         printk(KERN_INFO "adb: finished probe task...\n");
 235
 236         up(&adb_probe_mutex);
 237
 238         return 0;
 239 }
 240
 241 static void
 242 __adb_probe_task(struct work_struct *bullshit)
 243 {
 244         kthread_run(adb_probe_task, NULL, "kadbprobe");
 245 }
 246
 247 static DECLARE_WORK(adb_reset_work, __adb_probe_task);
 248
 249 int
 250 adb_reset_bus(void)
 251 {
 252         if (__adb_probe_sync) {
 253                 do_adb_reset_bus();
 254                 return 0;
 255         }
 256
 257         down(&adb_probe_mutex);
 258         schedule_work(&adb_reset_work);
 259         return 0;
 260 }
 261
 262 #ifdef CONFIG_PM
 263 /*
 264  * notify clients before sleep
 265  */
 266 static int adb_suspend(struct platform_device *dev, pm_message_t state)
 267 {
 268         adb_got_sleep = 1;
 269         /* We need to get a lock on the probe thread */
 270         down(&adb_probe_mutex);
 271         /* Stop autopoll */
 272         if (adb_controller->autopoll)
 273                 adb_controller->autopoll(0);
 274         blocking_notifier_call_chain(&adb_client_list, ADB_MSG_POWERDOWN, NULL);
 275
 276         return 0;
 277 }
 278
 279 /*
 280  * reset bus after sleep
 281  */
 282 static int adb_resume(struct platform_device *dev)
 283 {
 284         adb_got_sleep = 0;
 285         up(&adb_probe_mutex);
 286         adb_reset_bus();
 287
 288         return 0;
 289 }
 290 #endif /* CONFIG_PM */
 291
 292 static int __init adb_init(void)
 293 {
 294         struct adb_driver *driver;
 295         int i;
 296
 297 #ifdef CONFIG_PPC32
 298         if (!machine_is(chrp) && !machine_is(powermac))
 299                 return 0;
 300 #endif
 301 #ifdef CONFIG_MAC
 302         if (!MACH_IS_MAC)
 303                 return 0;
 304 #endif
 305
 306         /* xmon may do early-init */
 307         if (adb_inited)
 308                 return 0;
 309         adb_inited = 1;
 310
 311         adb_controller = NULL;
 312
 313         i = 0;
 314         while ((driver = adb_driver_list[i++]) != NULL) {
 315                 if (!driver->probe()) {
 316                         adb_controller = driver;
 317                         break;
 318                 }
 319         }
 320         if (adb_controller != NULL && adb_controller->init &&
 321             adb_controller->init())
 322                 adb_controller = NULL;
 323         if (adb_controller == NULL) {
 324                 printk(KERN_WARNING "Warning: no ADB interface detected\n");
 325         } else {
 326 #ifdef CONFIG_PPC
 327                 if (of_machine_is_compatible("AAPL,PowerBook1998") ||
 328                         of_machine_is_compatible("PowerBook1,1"))
 329                         sleepy_trackpad = 1;
 330 #endif /* CONFIG_PPC */
 331
 332                 adbdev_init();
 333                 adb_reset_bus();
 334         }
 335         return 0;
 336 }
 337
 338 device_initcall(adb_init);
 339
 340 static int
 341 do_adb_reset_bus(void)
 342 {
 343         int ret;
 344
 345         if (adb_controller == NULL)
 346                 return -ENXIO;
 347
 348         if (adb_controller->autopoll)
 349                 adb_controller->autopoll(0);
 350
 351         blocking_notifier_call_chain(&adb_client_list,
 352                 ADB_MSG_PRE_RESET, NULL);
 353
 354         if (sleepy_trackpad) {
 355                 /* Let the trackpad settle down */
 356                 msleep(500);
 357         }
 358
 359         mutex_lock(&adb_handler_mutex);
 360         write_lock_irq(&adb_handler_lock);
 361         memset(adb_handler, 0, sizeof(adb_handler));
 362         write_unlock_irq(&adb_handler_lock);
 363
 364         /* That one is still a bit synchronous, oh well... */
 365         if (adb_controller->reset_bus)
 366                 ret = adb_controller->reset_bus();
 367         else
 368                 ret = 0;
 369
 370         if (sleepy_trackpad) {
 371                 /* Let the trackpad settle down */
 372                 msleep(1500);
 373         }
 374
 375         if (!ret) {
 376                 autopoll_devs = adb_scan_bus();
 377                 if (adb_controller->autopoll)
 378                         adb_controller->autopoll(autopoll_devs);
 379         }
 380         mutex_unlock(&adb_handler_mutex);
 381
 382         blocking_notifier_call_chain(&adb_client_list,
 383                 ADB_MSG_POST_RESET, NULL);
 384
 385         return ret;
 386 }
 387
 388 void
 389 adb_poll(void)
 390 {
 391         if ((adb_controller == NULL)||(adb_controller->poll == NULL))
 392                 return;
 393         adb_controller->poll();
 394 }
 395
 396 static void adb_sync_req_done(struct adb_request *req)
 397 {
 398         struct completion *comp = req->arg;
 399
 400         complete(comp);
 401 }
 402
 403 int
 404 adb_request(struct adb_request *req, void (*done)(struct adb_request *),
 405             int flags, int nbytes, ...)
 406 {
 407         va_list list;
 408         int i;
 409         int rc;
 410         struct completion comp;
 411
 412         if ((adb_controller == NULL) || (adb_controller->send_request == NULL))
 413                 return -ENXIO;
 414         if (nbytes < 1)
 415                 return -EINVAL;
 416
 417         req->nbytes = nbytes+1;
 418         req->done = done;
 419         req->reply_expected = flags & ADBREQ_REPLY;
 420         req->data[0] = ADB_PACKET;
 421         va_start(list, nbytes);
 422         for (i = 0; i < nbytes; ++i)
 423                 req->data[i+1] = va_arg(list, int);
 424         va_end(list);
 425
 426         if (flags & ADBREQ_NOSEND)
 427                 return 0;
 428
 429         /* Synchronous requests block using an on-stack completion */
 430         if (flags & ADBREQ_SYNC) {
 431                 WARN_ON(done);
 432                 req->done = adb_sync_req_done;
 433                 req->arg = &comp;
 434                 init_completion(&comp);
 435         }
 436
 437         rc = adb_controller->send_request(req, 0);
 438
 439         if ((flags & ADBREQ_SYNC) && !rc && !req->complete)
 440                 wait_for_completion(&comp);
 441
 442         return rc;
 443 }
 444
 445  /* Ultimately this should return the number of devices with
 446     the given default id.
 447     And it does it now ! Note: changed behaviour: This function
 448     will now register if default_id _and_ handler_id both match
 449     but handler_id can be left to 0 to match with default_id only.
 450     When handler_id is set, this function will try to adjust
 451     the handler_id id it doesn't match. */
 452 int
 453 adb_register(int default_id, int handler_id, struct adb_ids *ids,
 454              void (*handler)(unsigned char *, int, int))
 455 {
 456         int i;
 457
 458         mutex_lock(&adb_handler_mutex);
 459         ids->nids = 0;
 460         for (i = 1; i < 16; i++) {
 461                 if ((adb_handler[i].original_address == default_id) &&
 462                     (!handler_id || (handler_id == adb_handler[i].handler_id) ||
 463                     try_handler_change(i, handler_id))) {
 464                         if (adb_handler[i].handler != 0) {
 465                                 printk(KERN_ERR
 466                                        "Two handlers for ADB device %d\n",
 467                                        default_id);
 468                                 continue;
 469                         }
 470                         write_lock_irq(&adb_handler_lock);
 471                         adb_handler[i].handler = handler;
 472                         write_unlock_irq(&adb_handler_lock);
 473                         ids->id[ids->nids++] = i;
 474                 }
 475         }
 476         mutex_unlock(&adb_handler_mutex);
 477         return ids->nids;
 478 }
 479
 480 int
 481 adb_unregister(int index)
 482 {
 483         int ret = -ENODEV;
 484
 485         mutex_lock(&adb_handler_mutex);
 486         write_lock_irq(&adb_handler_lock);
 487         if (adb_handler[index].handler) {
 488                 while(adb_handler[index].busy) {
 489                         write_unlock_irq(&adb_handler_lock);
 490                         yield();
 491                         write_lock_irq(&adb_handler_lock);
 492                 }
 493                 ret = 0;
 494                 adb_handler[index].handler = NULL;
 495         }
 496         write_unlock_irq(&adb_handler_lock);
 497         mutex_unlock(&adb_handler_mutex);
 498         return ret;
 499 }
 500
 501 void
 502 adb_input(unsigned char *buf, int nb, int autopoll)
 503 {
 504         int i, id;
 505         static int dump_adb_input = 0;
 506         unsigned long flags;
 507
 508         void (*handler)(unsigned char *, int, int);
 509
 510         /* We skip keystrokes and mouse moves when the sleep process
 511          * has been started. We stop autopoll, but this is another security
 512          */
 513         if (adb_got_sleep)
 514                 return;
 515
 516         id = buf[0] >> 4;
 517         if (dump_adb_input) {
 518                 printk(KERN_INFO "adb packet: ");
 519                 for (i = 0; i < nb; ++i)
 520                         printk(" %x", buf[i]);
 521                 printk(", id = %d\n", id);
 522         }
 523         write_lock_irqsave(&adb_handler_lock, flags);
 524         handler = adb_handler[id].handler;
 525         if (handler != NULL)
 526                 adb_handler[id].busy = 1;
 527         write_unlock_irqrestore(&adb_handler_lock, flags);
 528         if (handler != NULL) {
 529                 (*handler)(buf, nb, autopoll);
 530                 wmb();
 531                 adb_handler[id].busy = 0;
 532         }
 533
 534 }
 535
 536 /* Try to change handler to new_id. Will return 1 if successful. */
 537 static int try_handler_change(int address, int new_id)
 538 {
 539         struct adb_request req;
 540
 541         if (adb_handler[address].handler_id == new_id)
 542             return 1;
 543         adb_request(&req, NULL, ADBREQ_SYNC, 3,
 544             ADB_WRITEREG(address, 3), address | 0x20, new_id);
 545         adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 546             ADB_READREG(address, 3));
 547         if (req.reply_len < 2)
 548             return 0;
 549         if (req.reply[2] != new_id)
 550             return 0;
 551         adb_handler[address].handler_id = req.reply[2];
 552
 553         return 1;
 554 }
 555
 556 int
 557 adb_try_handler_change(int address, int new_id)
 558 {
 559         int ret;
 560
 561         mutex_lock(&adb_handler_mutex);
 562         ret = try_handler_change(address, new_id);
 563         mutex_unlock(&adb_handler_mutex);
 564         return ret;
 565 }
 566
 567 int
 568 adb_get_infos(int address, int *original_address, int *handler_id)
 569 {
 570         mutex_lock(&adb_handler_mutex);
 571         *original_address = adb_handler[address].original_address;
 572         *handler_id = adb_handler[address].handler_id;
 573         mutex_unlock(&adb_handler_mutex);
 574
 575         return (*original_address != 0);
 576 }
 577
 578
 579 /*
 580  * /dev/adb device driver.
 581  */
 582
 583 #define ADB_MAJOR       56      /* major number for /dev/adb */
 584
 585 struct adbdev_state {
 586         spinlock_t      lock;
 587         atomic_t        n_pending;
 588         struct adb_request *completed;
 589         wait_queue_head_t wait_queue;
 590         int             inuse;
 591 };
 592
 593 static void adb_write_done(struct adb_request *req)
 594 {
 595         struct adbdev_state *state = (struct adbdev_state *) req->arg;
 596         unsigned long flags;
 597
 598         if (!req->complete) {
 599                 req->reply_len = 0;
 600                 req->complete = 1;
 601         }
 602         spin_lock_irqsave(&state->lock, flags);
 603         atomic_dec(&state->n_pending);
 604         if (!state->inuse) {
 605                 kfree(req);
 606                 if (atomic_read(&state->n_pending) == 0) {
 607                         spin_unlock_irqrestore(&state->lock, flags);
 608                         kfree(state);
 609                         return;
 610                 }
 611         } else {
 612                 struct adb_request **ap = &state->completed;
 613                 while (*ap != NULL)
 614                         ap = &(*ap)->next;
 615                 req->next = NULL;
 616                 *ap = req;
 617                 wake_up_interruptible(&state->wait_queue);
 618         }
 619         spin_unlock_irqrestore(&state->lock, flags);
 620 }
 621
 622 static int
 623 do_adb_query(struct adb_request *req)
 624 {
 625         int     ret = -EINVAL;
 626
 627         switch(req->data[1])
 628         {
 629         case ADB_QUERY_GETDEVINFO:
 630                 if (req->nbytes < 3)
 631                         break;
 632                 mutex_lock(&adb_handler_mutex);
 633                 req->reply[0] = adb_handler[req->data[2]].original_address;
 634                 req->reply[1] = adb_handler[req->data[2]].handler_id;
 635                 mutex_unlock(&adb_handler_mutex);
 636                 req->complete = 1;
 637                 req->reply_len = 2;
 638                 adb_write_done(req);
 639                 ret = 0;
 640                 break;
 641         }
 642         return ret;
 643 }
 644
 645 static int adb_open(struct inode *inode, struct file *file)
 646 {
 647         struct adbdev_state *state;
 648         int ret = 0;
 649
 650         mutex_lock(&adb_mutex);
 651         if (iminor(inode) > 0 || adb_controller == NULL) {
 652                 ret = -ENXIO;
 653                 goto out;
 654         }
 655         state = kmalloc(sizeof(struct adbdev_state), GFP_KERNEL);
 656         if (state == 0) {
 657                 ret = -ENOMEM;
 658                 goto out;
 659         }
 660         file->private_data = state;
 661         spin_lock_init(&state->lock);
 662         atomic_set(&state->n_pending, 0);
 663         state->completed = NULL;
 664         init_waitqueue_head(&state->wait_queue);
 665         state->inuse = 1;
 666
 667 out:
 668         mutex_unlock(&adb_mutex);
 669         return ret;
 670 }
 671
 672 static int adb_release(struct inode *inode, struct file *file)
 673 {
 674         struct adbdev_state *state = file->private_data;
 675         unsigned long flags;
 676
 677         mutex_lock(&adb_mutex);
 678         if (state) {
 679                 file->private_data = NULL;
 680                 spin_lock_irqsave(&state->lock, flags);
 681                 if (atomic_read(&state->n_pending) == 0
 682                     && state->completed == NULL) {
 683                         spin_unlock_irqrestore(&state->lock, flags);
 684                         kfree(state);
 685                 } else {
 686                         state->inuse = 0;
 687                         spin_unlock_irqrestore(&state->lock, flags);
 688                 }
 689         }
 690         mutex_unlock(&adb_mutex);
 691         return 0;
 692 }
 693
 694 static ssize_t adb_read(struct file *file, char __user *buf,
 695                         size_t count, loff_t *ppos)
 696 {
 697         int ret = 0;
 698         struct adbdev_state *state = file->private_data;
 699         struct adb_request *req;
 700         wait_queue_t wait = __WAITQUEUE_INITIALIZER(wait,current);
 701         unsigned long flags;
 702
 703         if (count < 2)
 704                 return -EINVAL;
 705         if (count > sizeof(req->reply))
 706                 count = sizeof(req->reply);
 707         if (!access_ok(VERIFY_WRITE, buf, count))
 708                 return -EFAULT;
 709
 710         req = NULL;
 711         spin_lock_irqsave(&state->lock, flags);
 712         add_wait_queue(&state->wait_queue, &wait);
 713         set_current_state(TASK_INTERRUPTIBLE);
 714
 715         for (;;) {
 716                 req = state->completed;
 717                 if (req != NULL)
 718                         state->completed = req->next;
 719                 else if (atomic_read(&state->n_pending) == 0)
 720                         ret = -EIO;
 721                 if (req != NULL || ret != 0)
 722                         break;
 723
 724                 if (file->f_flags & O_NONBLOCK) {
 725                         ret = -EAGAIN;
 726                         break;
 727                 }
 728                 if (signal_pending(current)) {
 729                         ret = -ERESTARTSYS;
 730                         break;
 731                 }
 732                 spin_unlock_irqrestore(&state->lock, flags);
 733                 schedule();
 734                 spin_lock_irqsave(&state->lock, flags);
 735         }
 736
 737         set_current_state(TASK_RUNNING);
 738         remove_wait_queue(&state->wait_queue, &wait);
 739         spin_unlock_irqrestore(&state->lock, flags);
 740
 741         if (ret)
 742                 return ret;
 743
 744         ret = req->reply_len;
 745         if (ret > count)
 746                 ret = count;
 747         if (ret > 0 && copy_to_user(buf, req->reply, ret))
 748                 ret = -EFAULT;
 749
 750         kfree(req);
 751         return ret;
 752 }
 753
 754 static ssize_t adb_write(struct file *file, const char __user *buf,
 755                          size_t count, loff_t *ppos)
 756 {
 757         int ret/*, i*/;
 758         struct adbdev_state *state = file->private_data;
 759         struct adb_request *req;
 760
 761         if (count < 2 || count > sizeof(req->data))
 762                 return -EINVAL;
 763         if (adb_controller == NULL)
 764                 return -ENXIO;
 765         if (!access_ok(VERIFY_READ, buf, count))
 766                 return -EFAULT;
 767
 768         req = kmalloc(sizeof(struct adb_request),
 769                                              GFP_KERNEL);
 770         if (req == NULL)
 771                 return -ENOMEM;
 772
 773         req->nbytes = count;
 774         req->done = adb_write_done;
 775         req->arg = (void *) state;
 776         req->complete = 0;
 777
 778         ret = -EFAULT;
 779         if (copy_from_user(req->data, buf, count))
 780                 goto out;
 781
 782         atomic_inc(&state->n_pending);
 783
 784         /* If a probe is in progress or we are sleeping, wait for it to complete */
 785         down(&adb_probe_mutex);
 786
 787         /* Queries are special requests sent to the ADB driver itself */
 788         if (req->data[0] == ADB_QUERY) {
 789                 if (count > 1)
 790                         ret = do_adb_query(req);
 791                 else
 792                         ret = -EINVAL;
 793                 up(&adb_probe_mutex);
 794         }
 795         /* Special case for ADB_BUSRESET request, all others are sent to
 796            the controller */
 797         else if ((req->data[0] == ADB_PACKET)&&(count > 1)
 798                 &&(req->data[1] == ADB_BUSRESET)) {
 799                 ret = do_adb_reset_bus();
 800                 up(&adb_probe_mutex);
 801                 atomic_dec(&state->n_pending);
 802                 if (ret == 0)
 803                         ret = count;
 804                 goto out;
 805         } else {
 806                 req->reply_expected = ((req->data[1] & 0xc) == 0xc);
 807                 if (adb_controller && adb_controller->send_request)
 808                         ret = adb_controller->send_request(req, 0);
 809                 else
 810                         ret = -ENXIO;
 811                 up(&adb_probe_mutex);
 812         }
 813
 814         if (ret != 0) {
 815                 atomic_dec(&state->n_pending);
 816                 goto out;
 817         }
 818         return count;
 819
 820 out:
 821         kfree(req);
 822         return ret;
 823 }
 824
 825 static const struct file_operations adb_fops = {
 826         .owner          = THIS_MODULE,
 827         .llseek         = no_llseek,
 828         .read           = adb_read,
 829         .write          = adb_write,
 830         .open           = adb_open,
 831         .release        = adb_release,
 832 };
 833
 834 static struct platform_driver adb_pfdrv = {
 835         .driver = {
 836                 .name = "adb",
 837         },
 838 #ifdef CONFIG_PM
 839         .suspend = adb_suspend,
 840         .resume = adb_resume,
 841 #endif
 842 };
 843
 844 static struct platform_device adb_pfdev = {
 845         .name = "adb",
 846 };
 847
 848 static int __init
 849 adb_dummy_probe(struct platform_device *dev)
 850 {
 851         if (dev == &adb_pfdev)
 852                 return 0;
 853         return -ENODEV;
 854 }
 855
 856 static void __init
 857 adbdev_init(void)
 858 {
 859         if (register_chrdev(ADB_MAJOR, "adb", &adb_fops)) {
 860                 printk(KERN_ERR "adb: unable to get major %d\n", ADB_MAJOR);
 861                 return;
 862         }
 863
 864         adb_dev_class = class_create(THIS_MODULE, "adb");
 865         if (IS_ERR(adb_dev_class))
 866                 return;
 867         device_create(adb_dev_class, NULL, MKDEV(ADB_MAJOR, 0), NULL, "adb");
 868
 869         platform_device_register(&adb_pfdev);
 870         platform_driver_probe(&adb_pfdrv, adb_dummy_probe);
 871 }