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 <linux/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                         } else {
 197                                 /*
 198                                  * No devices left at address i; move the
 199                                  * one(s) we moved to `highFree' back to i.
 200                                  */
 201                                 adb_request(&req, NULL, ADBREQ_SYNC, 3,
 202                                             (highFree << 4) | 0xb,
 203                                             (i | 0x60), 0xfe);
 204                         }
 205                 }
 206         }
 207
 208         /* Now fill in the handler_id field of the adb_handler entries. */
 209         printk(KERN_DEBUG "adb devices:");
 210         for (i = 1; i < 16; i++) {
 211                 if (adb_handler[i].original_address == 0)
 212                         continue;
 213                 adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 214                             (i << 4) | 0xf);
 215                 adb_handler[i].handler_id = req.reply[2];
 216                 printk(" [%d]: %d %x", i, adb_handler[i].original_address,
 217                        adb_handler[i].handler_id);
 218                 devmask |= 1 << i;
 219         }
 220         printk("\n");
 221         return devmask;
 222 }
 223
 224 /*
 225  * This kernel task handles ADB probing. It dies once probing is
 226  * completed.
 227  */
 228 static int
 229 adb_probe_task(void *x)
 230 {
 231         printk(KERN_INFO "adb: starting probe task...\n");
 232         do_adb_reset_bus();
 233         printk(KERN_INFO "adb: finished probe task...\n");
 234
 235         up(&adb_probe_mutex);
 236
 237         return 0;
 238 }
 239
 240 static void
 241 __adb_probe_task(struct work_struct *bullshit)
 242 {
 243         kthread_run(adb_probe_task, NULL, "kadbprobe");
 244 }
 245
 246 static DECLARE_WORK(adb_reset_work, __adb_probe_task);
 247
 248 int
 249 adb_reset_bus(void)
 250 {
 251         if (__adb_probe_sync) {
 252                 do_adb_reset_bus();
 253                 return 0;
 254         }
 255
 256         down(&adb_probe_mutex);
 257         schedule_work(&adb_reset_work);
 258         return 0;
 259 }
 260
 261 #ifdef CONFIG_PM
 262 /*
 263  * notify clients before sleep
 264  */
 265 static int __adb_suspend(struct platform_device *dev, pm_message_t state)
 266 {
 267         adb_got_sleep = 1;
 268         /* We need to get a lock on the probe thread */
 269         down(&adb_probe_mutex);
 270         /* Stop autopoll */
 271         if (adb_controller->autopoll)
 272                 adb_controller->autopoll(0);
 273         blocking_notifier_call_chain(&adb_client_list, ADB_MSG_POWERDOWN, NULL);
 274
 275         return 0;
 276 }
 277
 278 static int adb_suspend(struct device *dev)
 279 {
 280         return __adb_suspend(to_platform_device(dev), PMSG_SUSPEND);
 281 }
 282
 283 static int adb_freeze(struct device *dev)
 284 {
 285         return __adb_suspend(to_platform_device(dev), PMSG_FREEZE);
 286 }
 287
 288 static int adb_poweroff(struct device *dev)
 289 {
 290         return __adb_suspend(to_platform_device(dev), PMSG_HIBERNATE);
 291 }
 292
 293 /*
 294  * reset bus after sleep
 295  */
 296 static int __adb_resume(struct platform_device *dev)
 297 {
 298         adb_got_sleep = 0;
 299         up(&adb_probe_mutex);
 300         adb_reset_bus();
 301
 302         return 0;
 303 }
 304
 305 static int adb_resume(struct device *dev)
 306 {
 307         return __adb_resume(to_platform_device(dev));
 308 }
 309 #endif /* CONFIG_PM */
 310
 311 static int __init adb_init(void)
 312 {
 313         struct adb_driver *driver;
 314         int i;
 315
 316 #ifdef CONFIG_PPC32
 317         if (!machine_is(chrp) && !machine_is(powermac))
 318                 return 0;
 319 #endif
 320 #ifdef CONFIG_MAC
 321         if (!MACH_IS_MAC)
 322                 return 0;
 323 #endif
 324
 325         /* xmon may do early-init */
 326         if (adb_inited)
 327                 return 0;
 328         adb_inited = 1;
 329
 330         adb_controller = NULL;
 331
 332         i = 0;
 333         while ((driver = adb_driver_list[i++]) != NULL) {
 334                 if (!driver->probe()) {
 335                         adb_controller = driver;
 336                         break;
 337                 }
 338         }
 339         if (adb_controller != NULL && adb_controller->init &&
 340             adb_controller->init())
 341                 adb_controller = NULL;
 342         if (adb_controller == NULL) {
 343                 printk(KERN_WARNING "Warning: no ADB interface detected\n");
 344         } else {
 345 #ifdef CONFIG_PPC
 346                 if (of_machine_is_compatible("AAPL,PowerBook1998") ||
 347                         of_machine_is_compatible("PowerBook1,1"))
 348                         sleepy_trackpad = 1;
 349 #endif /* CONFIG_PPC */
 350
 351                 adbdev_init();
 352                 adb_reset_bus();
 353         }
 354         return 0;
 355 }
 356
 357 device_initcall(adb_init);
 358
 359 static int
 360 do_adb_reset_bus(void)
 361 {
 362         int ret;
 363
 364         if (adb_controller == NULL)
 365                 return -ENXIO;
 366
 367         if (adb_controller->autopoll)
 368                 adb_controller->autopoll(0);
 369
 370         blocking_notifier_call_chain(&adb_client_list,
 371                 ADB_MSG_PRE_RESET, NULL);
 372
 373         if (sleepy_trackpad) {
 374                 /* Let the trackpad settle down */
 375                 msleep(500);
 376         }
 377
 378         mutex_lock(&adb_handler_mutex);
 379         write_lock_irq(&adb_handler_lock);
 380         memset(adb_handler, 0, sizeof(adb_handler));
 381         write_unlock_irq(&adb_handler_lock);
 382
 383         /* That one is still a bit synchronous, oh well... */
 384         if (adb_controller->reset_bus)
 385                 ret = adb_controller->reset_bus();
 386         else
 387                 ret = 0;
 388
 389         if (sleepy_trackpad) {
 390                 /* Let the trackpad settle down */
 391                 msleep(1500);
 392         }
 393
 394         if (!ret) {
 395                 autopoll_devs = adb_scan_bus();
 396                 if (adb_controller->autopoll)
 397                         adb_controller->autopoll(autopoll_devs);
 398         }
 399         mutex_unlock(&adb_handler_mutex);
 400
 401         blocking_notifier_call_chain(&adb_client_list,
 402                 ADB_MSG_POST_RESET, NULL);
 403
 404         return ret;
 405 }
 406
 407 void
 408 adb_poll(void)
 409 {
 410         if ((adb_controller == NULL)||(adb_controller->poll == NULL))
 411                 return;
 412         adb_controller->poll();
 413 }
 414 EXPORT_SYMBOL(adb_poll);
 415
 416 static void adb_sync_req_done(struct adb_request *req)
 417 {
 418         struct completion *comp = req->arg;
 419
 420         complete(comp);
 421 }
 422
 423 int
 424 adb_request(struct adb_request *req, void (*done)(struct adb_request *),
 425             int flags, int nbytes, ...)
 426 {
 427         va_list list;
 428         int i;
 429         int rc;
 430         struct completion comp;
 431
 432         if ((adb_controller == NULL) || (adb_controller->send_request == NULL))
 433                 return -ENXIO;
 434         if (nbytes < 1)
 435                 return -EINVAL;
 436
 437         req->nbytes = nbytes+1;
 438         req->done = done;
 439         req->reply_expected = flags & ADBREQ_REPLY;
 440         req->data[0] = ADB_PACKET;
 441         va_start(list, nbytes);
 442         for (i = 0; i < nbytes; ++i)
 443                 req->data[i+1] = va_arg(list, int);
 444         va_end(list);
 445
 446         if (flags & ADBREQ_NOSEND)
 447                 return 0;
 448
 449         /* Synchronous requests block using an on-stack completion */
 450         if (flags & ADBREQ_SYNC) {
 451                 WARN_ON(done);
 452                 req->done = adb_sync_req_done;
 453                 req->arg = &comp;
 454                 init_completion(&comp);
 455         }
 456
 457         rc = adb_controller->send_request(req, 0);
 458
 459         if ((flags & ADBREQ_SYNC) && !rc && !req->complete)
 460                 wait_for_completion(&comp);
 461
 462         return rc;
 463 }
 464 EXPORT_SYMBOL(adb_request);
 465
 466  /* Ultimately this should return the number of devices with
 467     the given default id.
 468     And it does it now ! Note: changed behaviour: This function
 469     will now register if default_id _and_ handler_id both match
 470     but handler_id can be left to 0 to match with default_id only.
 471     When handler_id is set, this function will try to adjust
 472     the handler_id id it doesn't match. */
 473 int
 474 adb_register(int default_id, int handler_id, struct adb_ids *ids,
 475              void (*handler)(unsigned char *, int, int))
 476 {
 477         int i;
 478
 479         mutex_lock(&adb_handler_mutex);
 480         ids->nids = 0;
 481         for (i = 1; i < 16; i++) {
 482                 if ((adb_handler[i].original_address == default_id) &&
 483                     (!handler_id || (handler_id == adb_handler[i].handler_id) ||
 484                     try_handler_change(i, handler_id))) {
 485                         if (adb_handler[i].handler != 0) {
 486                                 printk(KERN_ERR
 487                                        "Two handlers for ADB device %d\n",
 488                                        default_id);
 489                                 continue;
 490                         }
 491                         write_lock_irq(&adb_handler_lock);
 492                         adb_handler[i].handler = handler;
 493                         write_unlock_irq(&adb_handler_lock);
 494                         ids->id[ids->nids++] = i;
 495                 }
 496         }
 497         mutex_unlock(&adb_handler_mutex);
 498         return ids->nids;
 499 }
 500 EXPORT_SYMBOL(adb_register);
 501
 502 int
 503 adb_unregister(int index)
 504 {
 505         int ret = -ENODEV;
 506
 507         mutex_lock(&adb_handler_mutex);
 508         write_lock_irq(&adb_handler_lock);
 509         if (adb_handler[index].handler) {
 510                 while(adb_handler[index].busy) {
 511                         write_unlock_irq(&adb_handler_lock);
 512                         yield();
 513                         write_lock_irq(&adb_handler_lock);
 514                 }
 515                 ret = 0;
 516                 adb_handler[index].handler = NULL;
 517         }
 518         write_unlock_irq(&adb_handler_lock);
 519         mutex_unlock(&adb_handler_mutex);
 520         return ret;
 521 }
 522 EXPORT_SYMBOL(adb_unregister);
 523
 524 void
 525 adb_input(unsigned char *buf, int nb, int autopoll)
 526 {
 527         int i, id;
 528         static int dump_adb_input;
 529         unsigned long flags;
 530
 531         void (*handler)(unsigned char *, int, int);
 532
 533         /* We skip keystrokes and mouse moves when the sleep process
 534          * has been started. We stop autopoll, but this is another security
 535          */
 536         if (adb_got_sleep)
 537                 return;
 538
 539         id = buf[0] >> 4;
 540         if (dump_adb_input) {
 541                 printk(KERN_INFO "adb packet: ");
 542                 for (i = 0; i < nb; ++i)
 543                         printk(" %x", buf[i]);
 544                 printk(", id = %d\n", id);
 545         }
 546         write_lock_irqsave(&adb_handler_lock, flags);
 547         handler = adb_handler[id].handler;
 548         if (handler != NULL)
 549                 adb_handler[id].busy = 1;
 550         write_unlock_irqrestore(&adb_handler_lock, flags);
 551         if (handler != NULL) {
 552                 (*handler)(buf, nb, autopoll);
 553                 wmb();
 554                 adb_handler[id].busy = 0;
 555         }
 556
 557 }
 558
 559 /* Try to change handler to new_id. Will return 1 if successful. */
 560 static int try_handler_change(int address, int new_id)
 561 {
 562         struct adb_request req;
 563
 564         if (adb_handler[address].handler_id == new_id)
 565             return 1;
 566         adb_request(&req, NULL, ADBREQ_SYNC, 3,
 567             ADB_WRITEREG(address, 3), address | 0x20, new_id);
 568         adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 569             ADB_READREG(address, 3));
 570         if (req.reply_len < 2)
 571             return 0;
 572         if (req.reply[2] != new_id)
 573             return 0;
 574         adb_handler[address].handler_id = req.reply[2];
 575
 576         return 1;
 577 }
 578
 579 int
 580 adb_try_handler_change(int address, int new_id)
 581 {
 582         int ret;
 583
 584         mutex_lock(&adb_handler_mutex);
 585         ret = try_handler_change(address, new_id);
 586         mutex_unlock(&adb_handler_mutex);
 587         return ret;
 588 }
 589 EXPORT_SYMBOL(adb_try_handler_change);
 590
 591 int
 592 adb_get_infos(int address, int *original_address, int *handler_id)
 593 {
 594         mutex_lock(&adb_handler_mutex);
 595         *original_address = adb_handler[address].original_address;
 596         *handler_id = adb_handler[address].handler_id;
 597         mutex_unlock(&adb_handler_mutex);
 598
 599         return (*original_address != 0);
 600 }
 601
 602
 603 /*
 604  * /dev/adb device driver.
 605  */
 606
 607 #define ADB_MAJOR       56      /* major number for /dev/adb */
 608
 609 struct adbdev_state {
 610         spinlock_t      lock;
 611         atomic_t        n_pending;
 612         struct adb_request *completed;
 613         wait_queue_head_t wait_queue;
 614         int             inuse;
 615 };
 616
 617 static void adb_write_done(struct adb_request *req)
 618 {
 619         struct adbdev_state *state = (struct adbdev_state *) req->arg;
 620         unsigned long flags;
 621
 622         if (!req->complete) {
 623                 req->reply_len = 0;
 624                 req->complete = 1;
 625         }
 626         spin_lock_irqsave(&state->lock, flags);
 627         atomic_dec(&state->n_pending);
 628         if (!state->inuse) {
 629                 kfree(req);
 630                 if (atomic_read(&state->n_pending) == 0) {
 631                         spin_unlock_irqrestore(&state->lock, flags);
 632                         kfree(state);
 633                         return;
 634                 }
 635         } else {
 636                 struct adb_request **ap = &state->completed;
 637                 while (*ap != NULL)
 638                         ap = &(*ap)->next;
 639                 req->next = NULL;
 640                 *ap = req;
 641                 wake_up_interruptible(&state->wait_queue);
 642         }
 643         spin_unlock_irqrestore(&state->lock, flags);
 644 }
 645
 646 static int
 647 do_adb_query(struct adb_request *req)
 648 {
 649         int     ret = -EINVAL;
 650
 651         switch(req->data[1]) {
 652         case ADB_QUERY_GETDEVINFO:
 653                 if (req->nbytes < 3)
 654                         break;
 655                 mutex_lock(&adb_handler_mutex);
 656                 req->reply[0] = adb_handler[req->data[2]].original_address;
 657                 req->reply[1] = adb_handler[req->data[2]].handler_id;
 658                 mutex_unlock(&adb_handler_mutex);
 659                 req->complete = 1;
 660                 req->reply_len = 2;
 661                 adb_write_done(req);
 662                 ret = 0;
 663                 break;
 664         }
 665         return ret;
 666 }
 667
 668 static int adb_open(struct inode *inode, struct file *file)
 669 {
 670         struct adbdev_state *state;
 671         int ret = 0;
 672
 673         mutex_lock(&adb_mutex);
 674         if (iminor(inode) > 0 || adb_controller == NULL) {
 675                 ret = -ENXIO;
 676                 goto out;
 677         }
 678         state = kmalloc(sizeof(struct adbdev_state), GFP_KERNEL);
 679         if (state == 0) {
 680                 ret = -ENOMEM;
 681                 goto out;
 682         }
 683         file->private_data = state;
 684         spin_lock_init(&state->lock);
 685         atomic_set(&state->n_pending, 0);
 686         state->completed = NULL;
 687         init_waitqueue_head(&state->wait_queue);
 688         state->inuse = 1;
 689
 690 out:
 691         mutex_unlock(&adb_mutex);
 692         return ret;
 693 }
 694
 695 static int adb_release(struct inode *inode, struct file *file)
 696 {
 697         struct adbdev_state *state = file->private_data;
 698         unsigned long flags;
 699
 700         mutex_lock(&adb_mutex);
 701         if (state) {
 702                 file->private_data = NULL;
 703                 spin_lock_irqsave(&state->lock, flags);
 704                 if (atomic_read(&state->n_pending) == 0
 705                     && state->completed == NULL) {
 706                         spin_unlock_irqrestore(&state->lock, flags);
 707                         kfree(state);
 708                 } else {
 709                         state->inuse = 0;
 710                         spin_unlock_irqrestore(&state->lock, flags);
 711                 }
 712         }
 713         mutex_unlock(&adb_mutex);
 714         return 0;
 715 }
 716
 717 static ssize_t adb_read(struct file *file, char __user *buf,
 718                         size_t count, loff_t *ppos)
 719 {
 720         int ret = 0;
 721         struct adbdev_state *state = file->private_data;
 722         struct adb_request *req;
 723         DECLARE_WAITQUEUE(wait, current);
 724         unsigned long flags;
 725
 726         if (count < 2)
 727                 return -EINVAL;
 728         if (count > sizeof(req->reply))
 729                 count = sizeof(req->reply);
 730         if (!access_ok(VERIFY_WRITE, buf, count))
 731                 return -EFAULT;
 732
 733         req = NULL;
 734         spin_lock_irqsave(&state->lock, flags);
 735         add_wait_queue(&state->wait_queue, &wait);
 736         set_current_state(TASK_INTERRUPTIBLE);
 737
 738         for (;;) {
 739                 req = state->completed;
 740                 if (req != NULL)
 741                         state->completed = req->next;
 742                 else if (atomic_read(&state->n_pending) == 0)
 743                         ret = -EIO;
 744                 if (req != NULL || ret != 0)
 745                         break;
 746
 747                 if (file->f_flags & O_NONBLOCK) {
 748                         ret = -EAGAIN;
 749                         break;
 750                 }
 751                 if (signal_pending(current)) {
 752                         ret = -ERESTARTSYS;
 753                         break;
 754                 }
 755                 spin_unlock_irqrestore(&state->lock, flags);
 756                 schedule();
 757                 spin_lock_irqsave(&state->lock, flags);
 758         }
 759
 760         set_current_state(TASK_RUNNING);
 761         remove_wait_queue(&state->wait_queue, &wait);
 762         spin_unlock_irqrestore(&state->lock, flags);
 763
 764         if (ret)
 765                 return ret;
 766
 767         ret = req->reply_len;
 768         if (ret > count)
 769                 ret = count;
 770         if (ret > 0 && copy_to_user(buf, req->reply, ret))
 771                 ret = -EFAULT;
 772
 773         kfree(req);
 774         return ret;
 775 }
 776
 777 static ssize_t adb_write(struct file *file, const char __user *buf,
 778                          size_t count, loff_t *ppos)
 779 {
 780         int ret/*, i*/;
 781         struct adbdev_state *state = file->private_data;
 782         struct adb_request *req;
 783
 784         if (count < 2 || count > sizeof(req->data))
 785                 return -EINVAL;
 786         if (adb_controller == NULL)
 787                 return -ENXIO;
 788         if (!access_ok(VERIFY_READ, buf, count))
 789                 return -EFAULT;
 790
 791         req = kmalloc(sizeof(struct adb_request),
 792                                              GFP_KERNEL);
 793         if (req == NULL)
 794                 return -ENOMEM;
 795
 796         req->nbytes = count;
 797         req->done = adb_write_done;
 798         req->arg = (void *) state;
 799         req->complete = 0;
 800
 801         ret = -EFAULT;
 802         if (copy_from_user(req->data, buf, count))
 803                 goto out;
 804
 805         atomic_inc(&state->n_pending);
 806
 807         /* If a probe is in progress or we are sleeping, wait for it to complete */
 808         down(&adb_probe_mutex);
 809
 810         /* Queries are special requests sent to the ADB driver itself */
 811         if (req->data[0] == ADB_QUERY) {
 812                 if (count > 1)
 813                         ret = do_adb_query(req);
 814                 else
 815                         ret = -EINVAL;
 816                 up(&adb_probe_mutex);
 817         }
 818         /* Special case for ADB_BUSRESET request, all others are sent to
 819            the controller */
 820         else if ((req->data[0] == ADB_PACKET) && (count > 1)
 821                 && (req->data[1] == ADB_BUSRESET)) {
 822                 ret = do_adb_reset_bus();
 823                 up(&adb_probe_mutex);
 824                 atomic_dec(&state->n_pending);
 825                 if (ret == 0)
 826                         ret = count;
 827                 goto out;
 828         } else {
 829                 req->reply_expected = ((req->data[1] & 0xc) == 0xc);
 830                 if (adb_controller && adb_controller->send_request)
 831                         ret = adb_controller->send_request(req, 0);
 832                 else
 833                         ret = -ENXIO;
 834                 up(&adb_probe_mutex);
 835         }
 836
 837         if (ret != 0) {
 838                 atomic_dec(&state->n_pending);
 839                 goto out;
 840         }
 841         return count;
 842
 843 out:
 844         kfree(req);
 845         return ret;
 846 }
 847
 848 static const struct file_operations adb_fops = {
 849         .owner          = THIS_MODULE,
 850         .llseek         = no_llseek,
 851         .read           = adb_read,
 852         .write          = adb_write,
 853         .open           = adb_open,
 854         .release        = adb_release,
 855 };
 856
 857 #ifdef CONFIG_PM
 858 static const struct dev_pm_ops adb_dev_pm_ops = {
 859         .suspend = adb_suspend,
 860         .resume = adb_resume,
 861         /* Hibernate hooks */
 862         .freeze = adb_freeze,
 863         .thaw = adb_resume,
 864         .poweroff = adb_poweroff,
 865         .restore = adb_resume,
 866 };
 867 #endif
 868
 869 static struct platform_driver adb_pfdrv = {
 870         .driver = {
 871                 .name = "adb",
 872 #ifdef CONFIG_PM
 873                 .pm = &adb_dev_pm_ops,
 874 #endif
 875         },
 876 };
 877
 878 static struct platform_device adb_pfdev = {
 879         .name = "adb",
 880 };
 881
 882 static int __init
 883 adb_dummy_probe(struct platform_device *dev)
 884 {
 885         if (dev == &adb_pfdev)
 886                 return 0;
 887         return -ENODEV;
 888 }
 889
 890 static void __init
 891 adbdev_init(void)
 892 {
 893         if (register_chrdev(ADB_MAJOR, "adb", &adb_fops)) {
 894                 printk(KERN_ERR "adb: unable to get major %d\n", ADB_MAJOR);
 895                 return;
 896         }
 897
 898         adb_dev_class = class_create(THIS_MODULE, "adb");
 899         if (IS_ERR(adb_dev_class))
 900                 return;
 901         device_create(adb_dev_class, NULL, MKDEV(ADB_MAJOR, 0), NULL, "adb");
 902
 903         platform_device_register(&adb_pfdev);
 904         platform_driver_probe(&adb_pfdrv, adb_dummy_probe);
 905 }