linux/drivers/macintosh/adb.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Device driver for the Apple Desktop Bus
   4 * and the /dev/adb device on macintoshes.
   5 *
   6 * Copyright (C) 1996 Paul Mackerras.
   7 *
   8 * Modified to declare controllers as structures, added
   9 * client notification of bus reset and handles PowerBook
  10 * sleep, by Benjamin Herrenschmidt.
  11 *
  12 * To do:
  13 *
  14 * - /sys/bus/adb to list the devices and infos
  15 * - more /dev/adb to allow userland to receive the
  16 *   flow of auto-polling datas from a given device.
  17 * - move bus probe to a kernel thread
  18 */
  19
  20#include <linux/types.h>
  21#include <linux/errno.h>
  22#include <linux/kernel.h>
  23#include <linux/slab.h>
  24#include <linux/module.h>
  25#include <linux/fs.h>
  26#include <linux/mm.h>
  27#include <linux/sched/signal.h>
  28#include <linux/adb.h>
  29#include <linux/cuda.h>
  30#include <linux/pmu.h>
  31#include <linux/notifier.h>
  32#include <linux/wait.h>
  33#include <linux/init.h>
  34#include <linux/delay.h>
  35#include <linux/spinlock.h>
  36#include <linux/completion.h>
  37#include <linux/device.h>
  38#include <linux/kthread.h>
  39#include <linux/platform_device.h>
  40#include <linux/mutex.h>
  41
  42#include <linux/uaccess.h>
  43#ifdef CONFIG_PPC
  44#include <asm/prom.h>
  45#include <asm/machdep.h>
  46#endif
  47
  48
  49EXPORT_SYMBOL(adb_client_list);
  50
  51extern struct adb_driver via_macii_driver;
  52extern struct adb_driver via_cuda_driver;
  53extern struct adb_driver adb_iop_driver;
  54extern struct adb_driver via_pmu_driver;
  55extern struct adb_driver macio_adb_driver;
  56
  57static DEFINE_MUTEX(adb_mutex);
  58static struct adb_driver *adb_driver_list[] = {
  59#ifdef CONFIG_ADB_MACII
  60        &via_macii_driver,
  61#endif
  62#ifdef CONFIG_ADB_CUDA
  63        &via_cuda_driver,
  64#endif
  65#ifdef CONFIG_ADB_IOP
  66        &adb_iop_driver,
  67#endif
  68#if defined(CONFIG_ADB_PMU) || defined(CONFIG_ADB_PMU68K)
  69        &via_pmu_driver,
  70#endif
  71#ifdef CONFIG_ADB_MACIO
  72        &macio_adb_driver,
  73#endif
  74        NULL
  75};
  76
  77static struct class *adb_dev_class;
  78
  79static struct adb_driver *adb_controller;
  80BLOCKING_NOTIFIER_HEAD(adb_client_list);
  81static int adb_got_sleep;
  82static int adb_inited;
  83static DEFINE_SEMAPHORE(adb_probe_mutex);
  84static int sleepy_trackpad;
  85static int autopoll_devs;
  86int __adb_probe_sync;
  87
  88static int adb_scan_bus(void);
  89static int do_adb_reset_bus(void);
  90static void adbdev_init(void);
  91static int try_handler_change(int, int);
  92
  93static struct adb_handler {
  94        void (*handler)(unsigned char *, int, int);
  95        int original_address;
  96        int handler_id;
  97        int busy;
  98} adb_handler[16];
  99
 100/*
 101 * The adb_handler_mutex mutex protects all accesses to the original_address
 102 * and handler_id fields of adb_handler[i] for all i, and changes to the
 103 * handler field.
 104 * Accesses to the handler field are protected by the adb_handler_lock
 105 * rwlock.  It is held across all calls to any handler, so that by the
 106 * time adb_unregister returns, we know that the old handler isn't being
 107 * called.
 108 */
 109static DEFINE_MUTEX(adb_handler_mutex);
 110static DEFINE_RWLOCK(adb_handler_lock);
 111
 112#if 0
 113static void printADBreply(struct adb_request *req)
 114{
 115        int i;
 116
 117        printk("adb reply (%d)", req->reply_len);
 118        for(i = 0; i < req->reply_len; i++)
 119                printk(" %x", req->reply[i]);
 120        printk("\n");
 121
 122}
 123#endif
 124
 125static int adb_scan_bus(void)
 126{
 127        int i, highFree=0, noMovement;
 128        int devmask = 0;
 129        struct adb_request req;
 130        
 131        /* assumes adb_handler[] is all zeroes at this point */
 132        for (i = 1; i < 16; i++) {
 133                /* see if there is anything at address i */
 134                adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 135                            (i << 4) | 0xf);
 136                if (req.reply_len > 1)
 137                        /* one or more devices at this address */
 138                        adb_handler[i].original_address = i;
 139                else if (i > highFree)
 140                        highFree = i;
 141        }
 142
 143        /* Note we reset noMovement to 0 each time we move a device */
 144        for (noMovement = 1; noMovement < 2 && highFree > 0; noMovement++) {
 145                for (i = 1; i < 16; i++) {
 146                        if (adb_handler[i].original_address == 0)
 147                                continue;
 148                        /*
 149                         * Send a "talk register 3" command to address i
 150                         * to provoke a collision if there is more than
 151                         * one device at this address.
 152                         */
 153                        adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 154                                    (i << 4) | 0xf);
 155                        /*
 156                         * Move the device(s) which didn't detect a
 157                         * collision to address `highFree'.  Hopefully
 158                         * this only moves one device.
 159                         */
 160                        adb_request(&req, NULL, ADBREQ_SYNC, 3,
 161                                    (i<< 4) | 0xb, (highFree | 0x60), 0xfe);
 162                        /*
 163                         * See if anybody actually moved. This is suggested
 164                         * by HW TechNote 01:
 165                         *
 166                         * http://developer.apple.com/technotes/hw/hw_01.html
 167                         */
 168                        adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 169                                    (highFree << 4) | 0xf);
 170                        if (req.reply_len <= 1) continue;
 171                        /*
 172                         * Test whether there are any device(s) left
 173                         * at address i.
 174                         */
 175                        adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 176                                    (i << 4) | 0xf);
 177                        if (req.reply_len > 1) {
 178                                /*
 179                                 * There are still one or more devices
 180                                 * left at address i.  Register the one(s)
 181                                 * we moved to `highFree', and find a new
 182                                 * value for highFree.
 183                                 */
 184                                adb_handler[highFree].original_address =
 185                                        adb_handler[i].original_address;
 186                                while (highFree > 0 &&
 187                                       adb_handler[highFree].original_address)
 188                                        highFree--;
 189                                if (highFree <= 0)
 190                                        break;
 191
 192                                noMovement = 0;
 193                        } else {
 194                                /*
 195                                 * No devices left at address i; move the
 196                                 * one(s) we moved to `highFree' back to i.
 197                                 */
 198                                adb_request(&req, NULL, ADBREQ_SYNC, 3,
 199                                            (highFree << 4) | 0xb,
 200                                            (i | 0x60), 0xfe);
 201                        }
 202                }       
 203        }
 204
 205        /* Now fill in the handler_id field of the adb_handler entries. */
 206        printk(KERN_DEBUG "adb devices:");
 207        for (i = 1; i < 16; i++) {
 208                if (adb_handler[i].original_address == 0)
 209                        continue;
 210                adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 211                            (i << 4) | 0xf);
 212                adb_handler[i].handler_id = req.reply[2];
 213                printk(" [%d]: %d %x", i, adb_handler[i].original_address,
 214                       adb_handler[i].handler_id);
 215                devmask |= 1 << i;
 216        }
 217        printk("\n");
 218        return devmask;
 219}
 220
 221/*
 222 * This kernel task handles ADB probing. It dies once probing is
 223 * completed.
 224 */
 225static int
 226adb_probe_task(void *x)
 227{
 228        printk(KERN_INFO "adb: starting probe task...\n");
 229        do_adb_reset_bus();
 230        printk(KERN_INFO "adb: finished probe task...\n");
 231
 232        up(&adb_probe_mutex);
 233
 234        return 0;
 235}
 236
 237static void
 238__adb_probe_task(struct work_struct *bullshit)
 239{
 240        kthread_run(adb_probe_task, NULL, "kadbprobe");
 241}
 242
 243static DECLARE_WORK(adb_reset_work, __adb_probe_task);
 244
 245int
 246adb_reset_bus(void)
 247{
 248        if (__adb_probe_sync) {
 249                do_adb_reset_bus();
 250                return 0;
 251        }
 252
 253        down(&adb_probe_mutex);
 254        schedule_work(&adb_reset_work);
 255        return 0;
 256}
 257
 258#ifdef CONFIG_PM
 259/*
 260 * notify clients before sleep
 261 */
 262static int __adb_suspend(struct platform_device *dev, pm_message_t state)
 263{
 264        adb_got_sleep = 1;
 265        /* We need to get a lock on the probe thread */
 266        down(&adb_probe_mutex);
 267        /* Stop autopoll */
 268        if (adb_controller->autopoll)
 269                adb_controller->autopoll(0);
 270        blocking_notifier_call_chain(&adb_client_list, ADB_MSG_POWERDOWN, NULL);
 271
 272        return 0;
 273}
 274
 275static int adb_suspend(struct device *dev)
 276{
 277        return __adb_suspend(to_platform_device(dev), PMSG_SUSPEND);
 278}
 279
 280static int adb_freeze(struct device *dev)
 281{
 282        return __adb_suspend(to_platform_device(dev), PMSG_FREEZE);
 283}
 284
 285static int adb_poweroff(struct device *dev)
 286{
 287        return __adb_suspend(to_platform_device(dev), PMSG_HIBERNATE);
 288}
 289
 290/*
 291 * reset bus after sleep
 292 */
 293static int __adb_resume(struct platform_device *dev)
 294{
 295        adb_got_sleep = 0;
 296        up(&adb_probe_mutex);
 297        adb_reset_bus();
 298
 299        return 0;
 300}
 301
 302static int adb_resume(struct device *dev)
 303{
 304        return __adb_resume(to_platform_device(dev));
 305}
 306#endif /* CONFIG_PM */
 307
 308static int __init adb_init(void)
 309{
 310        struct adb_driver *driver;
 311        int i;
 312
 313#ifdef CONFIG_PPC32
 314        if (!machine_is(chrp) && !machine_is(powermac))
 315                return 0;
 316#endif
 317#ifdef CONFIG_MAC
 318        if (!MACH_IS_MAC)
 319                return 0;
 320#endif
 321
 322        /* xmon may do early-init */
 323        if (adb_inited)
 324                return 0;
 325        adb_inited = 1;
 326                
 327        adb_controller = NULL;
 328
 329        i = 0;
 330        while ((driver = adb_driver_list[i++]) != NULL) {
 331                if (!driver->probe()) {
 332                        adb_controller = driver;
 333                        break;
 334                }
 335        }
 336        if (adb_controller != NULL && adb_controller->init &&
 337            adb_controller->init())
 338                adb_controller = NULL;
 339        if (adb_controller == NULL) {
 340                printk(KERN_WARNING "Warning: no ADB interface detected\n");
 341        } else {
 342#ifdef CONFIG_PPC
 343                if (of_machine_is_compatible("AAPL,PowerBook1998") ||
 344                        of_machine_is_compatible("PowerBook1,1"))
 345                        sleepy_trackpad = 1;
 346#endif /* CONFIG_PPC */
 347
 348                adbdev_init();
 349                adb_reset_bus();
 350        }
 351        return 0;
 352}
 353
 354device_initcall(adb_init);
 355
 356static int
 357do_adb_reset_bus(void)
 358{
 359        int ret;
 360        
 361        if (adb_controller == NULL)
 362                return -ENXIO;
 363                
 364        if (adb_controller->autopoll)
 365                adb_controller->autopoll(0);
 366
 367        blocking_notifier_call_chain(&adb_client_list,
 368                ADB_MSG_PRE_RESET, NULL);
 369
 370        if (sleepy_trackpad) {
 371                /* Let the trackpad settle down */
 372                msleep(500);
 373        }
 374
 375        mutex_lock(&adb_handler_mutex);
 376        write_lock_irq(&adb_handler_lock);
 377        memset(adb_handler, 0, sizeof(adb_handler));
 378        write_unlock_irq(&adb_handler_lock);
 379
 380        /* That one is still a bit synchronous, oh well... */
 381        if (adb_controller->reset_bus)
 382                ret = adb_controller->reset_bus();
 383        else
 384                ret = 0;
 385
 386        if (sleepy_trackpad) {
 387                /* Let the trackpad settle down */
 388                msleep(1500);
 389        }
 390
 391        if (!ret) {
 392                autopoll_devs = adb_scan_bus();
 393                if (adb_controller->autopoll)
 394                        adb_controller->autopoll(autopoll_devs);
 395        }
 396        mutex_unlock(&adb_handler_mutex);
 397
 398        blocking_notifier_call_chain(&adb_client_list,
 399                ADB_MSG_POST_RESET, NULL);
 400        
 401        return ret;
 402}
 403
 404void
 405adb_poll(void)
 406{
 407        if ((adb_controller == NULL)||(adb_controller->poll == NULL))
 408                return;
 409        adb_controller->poll();
 410}
 411EXPORT_SYMBOL(adb_poll);
 412
 413static void adb_sync_req_done(struct adb_request *req)
 414{
 415        struct completion *comp = req->arg;
 416
 417        complete(comp);
 418}
 419
 420int
 421adb_request(struct adb_request *req, void (*done)(struct adb_request *),
 422            int flags, int nbytes, ...)
 423{
 424        va_list list;
 425        int i;
 426        int rc;
 427        struct completion comp;
 428
 429        if ((adb_controller == NULL) || (adb_controller->send_request == NULL))
 430                return -ENXIO;
 431        if (nbytes < 1)
 432                return -EINVAL;
 433
 434        req->nbytes = nbytes+1;
 435        req->done = done;
 436        req->reply_expected = flags & ADBREQ_REPLY;
 437        req->data[0] = ADB_PACKET;
 438        va_start(list, nbytes);
 439        for (i = 0; i < nbytes; ++i)
 440                req->data[i+1] = va_arg(list, int);
 441        va_end(list);
 442
 443        if (flags & ADBREQ_NOSEND)
 444                return 0;
 445
 446        /* Synchronous requests block using an on-stack completion */
 447        if (flags & ADBREQ_SYNC) {
 448                WARN_ON(done);
 449                req->done = adb_sync_req_done;
 450                req->arg = &comp;
 451                init_completion(&comp);
 452        }
 453
 454        rc = adb_controller->send_request(req, 0);
 455
 456        if ((flags & ADBREQ_SYNC) && !rc && !req->complete)
 457                wait_for_completion(&comp);
 458
 459        return rc;
 460}
 461EXPORT_SYMBOL(adb_request);
 462
 463 /* Ultimately this should return the number of devices with
 464    the given default id.
 465    And it does it now ! Note: changed behaviour: This function
 466    will now register if default_id _and_ handler_id both match
 467    but handler_id can be left to 0 to match with default_id only.
 468    When handler_id is set, this function will try to adjust
 469    the handler_id id it doesn't match. */
 470int
 471adb_register(int default_id, int handler_id, struct adb_ids *ids,
 472             void (*handler)(unsigned char *, int, int))
 473{
 474        int i;
 475
 476        mutex_lock(&adb_handler_mutex);
 477        ids->nids = 0;
 478        for (i = 1; i < 16; i++) {
 479                if ((adb_handler[i].original_address == default_id) &&
 480                    (!handler_id || (handler_id == adb_handler[i].handler_id) || 
 481                    try_handler_change(i, handler_id))) {
 482                        if (adb_handler[i].handler != 0) {
 483                                printk(KERN_ERR
 484                                       "Two handlers for ADB device %d\n",
 485                                       default_id);
 486                                continue;
 487                        }
 488                        write_lock_irq(&adb_handler_lock);
 489                        adb_handler[i].handler = handler;
 490                        write_unlock_irq(&adb_handler_lock);
 491                        ids->id[ids->nids++] = i;
 492                }
 493        }
 494        mutex_unlock(&adb_handler_mutex);
 495        return ids->nids;
 496}
 497EXPORT_SYMBOL(adb_register);
 498
 499int
 500adb_unregister(int index)
 501{
 502        int ret = -ENODEV;
 503
 504        mutex_lock(&adb_handler_mutex);
 505        write_lock_irq(&adb_handler_lock);
 506        if (adb_handler[index].handler) {
 507                while(adb_handler[index].busy) {
 508                        write_unlock_irq(&adb_handler_lock);
 509                        yield();
 510                        write_lock_irq(&adb_handler_lock);
 511                }
 512                ret = 0;
 513                adb_handler[index].handler = NULL;
 514        }
 515        write_unlock_irq(&adb_handler_lock);
 516        mutex_unlock(&adb_handler_mutex);
 517        return ret;
 518}
 519EXPORT_SYMBOL(adb_unregister);
 520
 521void
 522adb_input(unsigned char *buf, int nb, int autopoll)
 523{
 524        int i, id;
 525        static int dump_adb_input;
 526        unsigned long flags;
 527        
 528        void (*handler)(unsigned char *, int, int);
 529
 530        /* We skip keystrokes and mouse moves when the sleep process
 531         * has been started. We stop autopoll, but this is another security
 532         */
 533        if (adb_got_sleep)
 534                return;
 535                
 536        id = buf[0] >> 4;
 537        if (dump_adb_input) {
 538                printk(KERN_INFO "adb packet: ");
 539                for (i = 0; i < nb; ++i)
 540                        printk(" %x", buf[i]);
 541                printk(", id = %d\n", id);
 542        }
 543        write_lock_irqsave(&adb_handler_lock, flags);
 544        handler = adb_handler[id].handler;
 545        if (handler != NULL)
 546                adb_handler[id].busy = 1;
 547        write_unlock_irqrestore(&adb_handler_lock, flags);
 548        if (handler != NULL) {
 549                (*handler)(buf, nb, autopoll);
 550                wmb();
 551                adb_handler[id].busy = 0;
 552        }
 553                
 554}
 555
 556/* Try to change handler to new_id. Will return 1 if successful. */
 557static int try_handler_change(int address, int new_id)
 558{
 559        struct adb_request req;
 560
 561        if (adb_handler[address].handler_id == new_id)
 562            return 1;
 563        adb_request(&req, NULL, ADBREQ_SYNC, 3,
 564            ADB_WRITEREG(address, 3), address | 0x20, new_id);
 565        adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 566            ADB_READREG(address, 3));
 567        if (req.reply_len < 2)
 568            return 0;
 569        if (req.reply[2] != new_id)
 570            return 0;
 571        adb_handler[address].handler_id = req.reply[2];
 572
 573        return 1;
 574}
 575
 576int
 577adb_try_handler_change(int address, int new_id)
 578{
 579        int ret;
 580
 581        mutex_lock(&adb_handler_mutex);
 582        ret = try_handler_change(address, new_id);
 583        mutex_unlock(&adb_handler_mutex);
 584        return ret;
 585}
 586EXPORT_SYMBOL(adb_try_handler_change);
 587
 588int
 589adb_get_infos(int address, int *original_address, int *handler_id)
 590{
 591        mutex_lock(&adb_handler_mutex);
 592        *original_address = adb_handler[address].original_address;
 593        *handler_id = adb_handler[address].handler_id;
 594        mutex_unlock(&adb_handler_mutex);
 595
 596        return (*original_address != 0);
 597}
 598
 599
 600/*
 601 * /dev/adb device driver.
 602 */
 603
 604#define ADB_MAJOR       56      /* major number for /dev/adb */
 605
 606struct adbdev_state {
 607        spinlock_t      lock;
 608        atomic_t        n_pending;
 609        struct adb_request *completed;
 610        wait_queue_head_t wait_queue;
 611        int             inuse;
 612};
 613
 614static void adb_write_done(struct adb_request *req)
 615{
 616        struct adbdev_state *state = (struct adbdev_state *) req->arg;
 617        unsigned long flags;
 618
 619        if (!req->complete) {
 620                req->reply_len = 0;
 621                req->complete = 1;
 622        }
 623        spin_lock_irqsave(&state->lock, flags);
 624        atomic_dec(&state->n_pending);
 625        if (!state->inuse) {
 626                kfree(req);
 627                if (atomic_read(&state->n_pending) == 0) {
 628                        spin_unlock_irqrestore(&state->lock, flags);
 629                        kfree(state);
 630                        return;
 631                }
 632        } else {
 633                struct adb_request **ap = &state->completed;
 634                while (*ap != NULL)
 635                        ap = &(*ap)->next;
 636                req->next = NULL;
 637                *ap = req;
 638                wake_up_interruptible(&state->wait_queue);
 639        }
 640        spin_unlock_irqrestore(&state->lock, flags);
 641}
 642
 643static int
 644do_adb_query(struct adb_request *req)
 645{
 646        int     ret = -EINVAL;
 647
 648        switch(req->data[1]) {
 649        case ADB_QUERY_GETDEVINFO:
 650                if (req->nbytes < 3)
 651                        break;
 652                mutex_lock(&adb_handler_mutex);
 653                req->reply[0] = adb_handler[req->data[2]].original_address;
 654                req->reply[1] = adb_handler[req->data[2]].handler_id;
 655                mutex_unlock(&adb_handler_mutex);
 656                req->complete = 1;
 657                req->reply_len = 2;
 658                adb_write_done(req);
 659                ret = 0;
 660                break;
 661        }
 662        return ret;
 663}
 664
 665static int adb_open(struct inode *inode, struct file *file)
 666{
 667        struct adbdev_state *state;
 668        int ret = 0;
 669
 670        mutex_lock(&adb_mutex);
 671        if (iminor(inode) > 0 || adb_controller == NULL) {
 672                ret = -ENXIO;
 673                goto out;
 674        }
 675        state = kmalloc(sizeof(struct adbdev_state), GFP_KERNEL);
 676        if (state == 0) {
 677                ret = -ENOMEM;
 678                goto out;
 679        }
 680        file->private_data = state;
 681        spin_lock_init(&state->lock);
 682        atomic_set(&state->n_pending, 0);
 683        state->completed = NULL;
 684        init_waitqueue_head(&state->wait_queue);
 685        state->inuse = 1;
 686
 687out:
 688        mutex_unlock(&adb_mutex);
 689        return ret;
 690}
 691
 692static int adb_release(struct inode *inode, struct file *file)
 693{
 694        struct adbdev_state *state = file->private_data;
 695        unsigned long flags;
 696
 697        mutex_lock(&adb_mutex);
 698        if (state) {
 699                file->private_data = NULL;
 700                spin_lock_irqsave(&state->lock, flags);
 701                if (atomic_read(&state->n_pending) == 0
 702                    && state->completed == NULL) {
 703                        spin_unlock_irqrestore(&state->lock, flags);
 704                        kfree(state);
 705                } else {
 706                        state->inuse = 0;
 707                        spin_unlock_irqrestore(&state->lock, flags);
 708                }
 709        }
 710        mutex_unlock(&adb_mutex);
 711        return 0;
 712}
 713
 714static ssize_t adb_read(struct file *file, char __user *buf,
 715                        size_t count, loff_t *ppos)
 716{
 717        int ret = 0;
 718        struct adbdev_state *state = file->private_data;
 719        struct adb_request *req;
 720        DECLARE_WAITQUEUE(wait, current);
 721        unsigned long flags;
 722
 723        if (count < 2)
 724                return -EINVAL;
 725        if (count > sizeof(req->reply))
 726                count = sizeof(req->reply);
 727
 728        req = NULL;
 729        spin_lock_irqsave(&state->lock, flags);
 730        add_wait_queue(&state->wait_queue, &wait);
 731        set_current_state(TASK_INTERRUPTIBLE);
 732
 733        for (;;) {
 734                req = state->completed;
 735                if (req != NULL)
 736                        state->completed = req->next;
 737                else if (atomic_read(&state->n_pending) == 0)
 738                        ret = -EIO;
 739                if (req != NULL || ret != 0)
 740                        break;
 741                
 742                if (file->f_flags & O_NONBLOCK) {
 743                        ret = -EAGAIN;
 744                        break;
 745                }
 746                if (signal_pending(current)) {
 747                        ret = -ERESTARTSYS;
 748                        break;
 749                }
 750                spin_unlock_irqrestore(&state->lock, flags);
 751                schedule();
 752                spin_lock_irqsave(&state->lock, flags);
 753        }
 754
 755        set_current_state(TASK_RUNNING);
 756        remove_wait_queue(&state->wait_queue, &wait);
 757        spin_unlock_irqrestore(&state->lock, flags);
 758        
 759        if (ret)
 760                return ret;
 761
 762        ret = req->reply_len;
 763        if (ret > count)
 764                ret = count;
 765        if (ret > 0 && copy_to_user(buf, req->reply, ret))
 766                ret = -EFAULT;
 767
 768        kfree(req);
 769        return ret;
 770}
 771
 772static ssize_t adb_write(struct file *file, const char __user *buf,
 773                         size_t count, loff_t *ppos)
 774{
 775        int ret/*, i*/;
 776        struct adbdev_state *state = file->private_data;
 777        struct adb_request *req;
 778
 779        if (count < 2 || count > sizeof(req->data))
 780                return -EINVAL;
 781        if (adb_controller == NULL)
 782                return -ENXIO;
 783
 784        req = kmalloc(sizeof(struct adb_request),
 785                                             GFP_KERNEL);
 786        if (req == NULL)
 787                return -ENOMEM;
 788
 789        req->nbytes = count;
 790        req->done = adb_write_done;
 791        req->arg = (void *) state;
 792        req->complete = 0;
 793        
 794        ret = -EFAULT;
 795        if (copy_from_user(req->data, buf, count))
 796                goto out;
 797
 798        atomic_inc(&state->n_pending);
 799
 800        /* If a probe is in progress or we are sleeping, wait for it to complete */
 801        down(&adb_probe_mutex);
 802
 803        /* Queries are special requests sent to the ADB driver itself */
 804        if (req->data[0] == ADB_QUERY) {
 805                if (count > 1)
 806                        ret = do_adb_query(req);
 807                else
 808                        ret = -EINVAL;
 809                up(&adb_probe_mutex);
 810        }
 811        /* Special case for ADB_BUSRESET request, all others are sent to
 812           the controller */
 813        else if ((req->data[0] == ADB_PACKET) && (count > 1)
 814                && (req->data[1] == ADB_BUSRESET)) {
 815                ret = do_adb_reset_bus();
 816                up(&adb_probe_mutex);
 817                atomic_dec(&state->n_pending);
 818                if (ret == 0)
 819                        ret = count;
 820                goto out;
 821        } else {        
 822                req->reply_expected = ((req->data[1] & 0xc) == 0xc);
 823                if (adb_controller && adb_controller->send_request)
 824                        ret = adb_controller->send_request(req, 0);
 825                else
 826                        ret = -ENXIO;
 827                up(&adb_probe_mutex);
 828        }
 829
 830        if (ret != 0) {
 831                atomic_dec(&state->n_pending);
 832                goto out;
 833        }
 834        return count;
 835
 836out:
 837        kfree(req);
 838        return ret;
 839}
 840
 841static const struct file_operations adb_fops = {
 842        .owner          = THIS_MODULE,
 843        .llseek         = no_llseek,
 844        .read           = adb_read,
 845        .write          = adb_write,
 846        .open           = adb_open,
 847        .release        = adb_release,
 848};
 849
 850#ifdef CONFIG_PM
 851static const struct dev_pm_ops adb_dev_pm_ops = {
 852        .suspend = adb_suspend,
 853        .resume = adb_resume,
 854        /* Hibernate hooks */
 855        .freeze = adb_freeze,
 856        .thaw = adb_resume,
 857        .poweroff = adb_poweroff,
 858        .restore = adb_resume,
 859};
 860#endif
 861
 862static struct platform_driver adb_pfdrv = {
 863        .driver = {
 864                .name = "adb",
 865#ifdef CONFIG_PM
 866                .pm = &adb_dev_pm_ops,
 867#endif
 868        },
 869};
 870
 871static struct platform_device adb_pfdev = {
 872        .name = "adb",
 873};
 874
 875static int __init
 876adb_dummy_probe(struct platform_device *dev)
 877{
 878        if (dev == &adb_pfdev)
 879                return 0;
 880        return -ENODEV;
 881}
 882
 883static void __init
 884adbdev_init(void)
 885{
 886        if (register_chrdev(ADB_MAJOR, "adb", &adb_fops)) {
 887                printk(KERN_ERR "adb: unable to get major %d\n", ADB_MAJOR);
 888                return;
 889        }
 890
 891        adb_dev_class = class_create(THIS_MODULE, "adb");
 892        if (IS_ERR(adb_dev_class))
 893                return;
 894        device_create(adb_dev_class, NULL, MKDEV(ADB_MAJOR, 0), NULL, "adb");
 895
 896        platform_device_register(&adb_pfdev);
 897        platform_driver_probe(&adb_pfdrv, adb_dummy_probe);
 898}
 899