drivers/macintosh/adb.c

   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
  49 EXPORT_SYMBOL(adb_client_list);
  50
  51 extern struct adb_driver via_macii_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_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
  77 static struct class *adb_dev_class;
  78
  79 static struct adb_driver *adb_controller;
  80 BLOCKING_NOTIFIER_HEAD(adb_client_list);
  81 static int adb_got_sleep;
  82 static int adb_inited;
  83 static DEFINE_SEMAPHORE(adb_probe_mutex);
  84 static int sleepy_trackpad;
  85 static int autopoll_devs;
  86 int __adb_probe_sync;
  87
  88 static int adb_scan_bus(void);
  89 static int do_adb_reset_bus(void);
  90 static void adbdev_init(void);
  91 static int try_handler_change(int, int);
  92
  93 static 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  */
 109 static DEFINE_MUTEX(adb_handler_mutex);
 110 static DEFINE_RWLOCK(adb_handler_lock);
 111
 112 #if 0
 113 static 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
 125 static 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         pr_debug("adb devices:\n");
 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                 pr_debug(" [%d]: %d %x\n", i, adb_handler[i].original_address,
 214                          adb_handler[i].handler_id);
 215                 devmask |= 1 << i;
 216         }
 217         return devmask;
 218 }
 219
 220 /*
 221  * This kernel task handles ADB probing. It dies once probing is
 222  * completed.
 223  */
 224 static int
 225 adb_probe_task(void *x)
 226 {
 227         pr_debug("adb: starting probe task...\n");
 228         do_adb_reset_bus();
 229         pr_debug("adb: finished probe task...\n");
 230
 231         up(&adb_probe_mutex);
 232
 233         return 0;
 234 }
 235
 236 static void
 237 __adb_probe_task(struct work_struct *bullshit)
 238 {
 239         kthread_run(adb_probe_task, NULL, "kadbprobe");
 240 }
 241
 242 static DECLARE_WORK(adb_reset_work, __adb_probe_task);
 243
 244 int
 245 adb_reset_bus(void)
 246 {
 247         if (__adb_probe_sync) {
 248                 do_adb_reset_bus();
 249                 return 0;
 250         }
 251
 252         down(&adb_probe_mutex);
 253         schedule_work(&adb_reset_work);
 254         return 0;
 255 }
 256
 257 #ifdef CONFIG_PM
 258 /*
 259  * notify clients before sleep
 260  */
 261 static int __adb_suspend(struct platform_device *dev, pm_message_t state)
 262 {
 263         adb_got_sleep = 1;
 264         /* We need to get a lock on the probe thread */
 265         down(&adb_probe_mutex);
 266         /* Stop autopoll */
 267         if (adb_controller->autopoll)
 268                 adb_controller->autopoll(0);
 269         blocking_notifier_call_chain(&adb_client_list, ADB_MSG_POWERDOWN, NULL);
 270
 271         return 0;
 272 }
 273
 274 static int adb_suspend(struct device *dev)
 275 {
 276         return __adb_suspend(to_platform_device(dev), PMSG_SUSPEND);
 277 }
 278
 279 static int adb_freeze(struct device *dev)
 280 {
 281         return __adb_suspend(to_platform_device(dev), PMSG_FREEZE);
 282 }
 283
 284 static int adb_poweroff(struct device *dev)
 285 {
 286         return __adb_suspend(to_platform_device(dev), PMSG_HIBERNATE);
 287 }
 288
 289 /*
 290  * reset bus after sleep
 291  */
 292 static int __adb_resume(struct platform_device *dev)
 293 {
 294         adb_got_sleep = 0;
 295         up(&adb_probe_mutex);
 296         adb_reset_bus();
 297
 298         return 0;
 299 }
 300
 301 static int adb_resume(struct device *dev)
 302 {
 303         return __adb_resume(to_platform_device(dev));
 304 }
 305 #endif /* CONFIG_PM */
 306
 307 static int __init adb_init(void)
 308 {
 309         struct adb_driver *driver;
 310         int i;
 311
 312 #ifdef CONFIG_PPC32
 313         if (!machine_is(chrp) && !machine_is(powermac))
 314                 return 0;
 315 #endif
 316 #ifdef CONFIG_MAC
 317         if (!MACH_IS_MAC)
 318                 return 0;
 319 #endif
 320
 321         /* xmon may do early-init */
 322         if (adb_inited)
 323                 return 0;
 324         adb_inited = 1;
 325
 326         adb_controller = NULL;
 327
 328         i = 0;
 329         while ((driver = adb_driver_list[i++]) != NULL) {
 330                 if (!driver->probe()) {
 331                         adb_controller = driver;
 332                         break;
 333                 }
 334         }
 335         if (adb_controller != NULL && adb_controller->init &&
 336             adb_controller->init())
 337                 adb_controller = NULL;
 338         if (adb_controller == NULL) {
 339                 pr_warn("Warning: no ADB interface detected\n");
 340         } else {
 341 #ifdef CONFIG_PPC
 342                 if (of_machine_is_compatible("AAPL,PowerBook1998") ||
 343                         of_machine_is_compatible("PowerBook1,1"))
 344                         sleepy_trackpad = 1;
 345 #endif /* CONFIG_PPC */
 346
 347                 adbdev_init();
 348                 adb_reset_bus();
 349         }
 350         return 0;
 351 }
 352
 353 device_initcall(adb_init);
 354
 355 static int
 356 do_adb_reset_bus(void)
 357 {
 358         int ret;
 359
 360         if (adb_controller == NULL)
 361                 return -ENXIO;
 362
 363         if (adb_controller->autopoll)
 364                 adb_controller->autopoll(0);
 365
 366         blocking_notifier_call_chain(&adb_client_list,
 367                 ADB_MSG_PRE_RESET, NULL);
 368
 369         if (sleepy_trackpad) {
 370                 /* Let the trackpad settle down */
 371                 msleep(500);
 372         }
 373
 374         mutex_lock(&adb_handler_mutex);
 375         write_lock_irq(&adb_handler_lock);
 376         memset(adb_handler, 0, sizeof(adb_handler));
 377         write_unlock_irq(&adb_handler_lock);
 378
 379         /* That one is still a bit synchronous, oh well... */
 380         if (adb_controller->reset_bus)
 381                 ret = adb_controller->reset_bus();
 382         else
 383                 ret = 0;
 384
 385         if (sleepy_trackpad) {
 386                 /* Let the trackpad settle down */
 387                 msleep(1500);
 388         }
 389
 390         if (!ret) {
 391                 autopoll_devs = adb_scan_bus();
 392                 if (adb_controller->autopoll)
 393                         adb_controller->autopoll(autopoll_devs);
 394         }
 395         mutex_unlock(&adb_handler_mutex);
 396
 397         blocking_notifier_call_chain(&adb_client_list,
 398                 ADB_MSG_POST_RESET, NULL);
 399
 400         return ret;
 401 }
 402
 403 void
 404 adb_poll(void)
 405 {
 406         if ((adb_controller == NULL)||(adb_controller->poll == NULL))
 407                 return;
 408         adb_controller->poll();
 409 }
 410 EXPORT_SYMBOL(adb_poll);
 411
 412 static void adb_sync_req_done(struct adb_request *req)
 413 {
 414         struct completion *comp = req->arg;
 415
 416         complete(comp);
 417 }
 418
 419 int
 420 adb_request(struct adb_request *req, void (*done)(struct adb_request *),
 421             int flags, int nbytes, ...)
 422 {
 423         va_list list;
 424         int i;
 425         int rc;
 426         struct completion comp;
 427
 428         if ((adb_controller == NULL) || (adb_controller->send_request == NULL))
 429                 return -ENXIO;
 430         if (nbytes < 1)
 431                 return -EINVAL;
 432
 433         req->nbytes = nbytes+1;
 434         req->done = done;
 435         req->reply_expected = flags & ADBREQ_REPLY;
 436         req->data[0] = ADB_PACKET;
 437         va_start(list, nbytes);
 438         for (i = 0; i < nbytes; ++i)
 439                 req->data[i+1] = va_arg(list, int);
 440         va_end(list);
 441
 442         if (flags & ADBREQ_NOSEND)
 443                 return 0;
 444
 445         /* Synchronous requests block using an on-stack completion */
 446         if (flags & ADBREQ_SYNC) {
 447                 WARN_ON(done);
 448                 req->done = adb_sync_req_done;
 449                 req->arg = &comp;
 450                 init_completion(&comp);
 451         }
 452
 453         rc = adb_controller->send_request(req, 0);
 454
 455         if ((flags & ADBREQ_SYNC) && !rc && !req->complete)
 456                 wait_for_completion(&comp);
 457
 458         return rc;
 459 }
 460 EXPORT_SYMBOL(adb_request);
 461
 462  /* Ultimately this should return the number of devices with
 463     the given default id.
 464     And it does it now ! Note: changed behaviour: This function
 465     will now register if default_id _and_ handler_id both match
 466     but handler_id can be left to 0 to match with default_id only.
 467     When handler_id is set, this function will try to adjust
 468     the handler_id id it doesn't match. */
 469 int
 470 adb_register(int default_id, int handler_id, struct adb_ids *ids,
 471              void (*handler)(unsigned char *, int, int))
 472 {
 473         int i;
 474
 475         mutex_lock(&adb_handler_mutex);
 476         ids->nids = 0;
 477         for (i = 1; i < 16; i++) {
 478                 if ((adb_handler[i].original_address == default_id) &&
 479                     (!handler_id || (handler_id == adb_handler[i].handler_id) ||
 480                     try_handler_change(i, handler_id))) {
 481                         if (adb_handler[i].handler != 0) {
 482                                 pr_err("Two handlers for ADB device %d\n",
 483                                        default_id);
 484                                 continue;
 485                         }
 486                         write_lock_irq(&adb_handler_lock);
 487                         adb_handler[i].handler = handler;
 488                         write_unlock_irq(&adb_handler_lock);
 489                         ids->id[ids->nids++] = i;
 490                 }
 491         }
 492         mutex_unlock(&adb_handler_mutex);
 493         return ids->nids;
 494 }
 495 EXPORT_SYMBOL(adb_register);
 496
 497 int
 498 adb_unregister(int index)
 499 {
 500         int ret = -ENODEV;
 501
 502         mutex_lock(&adb_handler_mutex);
 503         write_lock_irq(&adb_handler_lock);
 504         if (adb_handler[index].handler) {
 505                 while(adb_handler[index].busy) {
 506                         write_unlock_irq(&adb_handler_lock);
 507                         yield();
 508                         write_lock_irq(&adb_handler_lock);
 509                 }
 510                 ret = 0;
 511                 adb_handler[index].handler = NULL;
 512         }
 513         write_unlock_irq(&adb_handler_lock);
 514         mutex_unlock(&adb_handler_mutex);
 515         return ret;
 516 }
 517 EXPORT_SYMBOL(adb_unregister);
 518
 519 void
 520 adb_input(unsigned char *buf, int nb, int autopoll)
 521 {
 522         int i, id;
 523         static int dump_adb_input;
 524         unsigned long flags;
 525
 526         void (*handler)(unsigned char *, int, int);
 527
 528         /* We skip keystrokes and mouse moves when the sleep process
 529          * has been started. We stop autopoll, but this is another security
 530          */
 531         if (adb_got_sleep)
 532                 return;
 533
 534         id = buf[0] >> 4;
 535         if (dump_adb_input) {
 536                 pr_info("adb packet: ");
 537                 for (i = 0; i < nb; ++i)
 538                         pr_cont(" %x", buf[i]);
 539                 pr_cont(", id = %d\n", id);
 540         }
 541         write_lock_irqsave(&adb_handler_lock, flags);
 542         handler = adb_handler[id].handler;
 543         if (handler != NULL)
 544                 adb_handler[id].busy = 1;
 545         write_unlock_irqrestore(&adb_handler_lock, flags);
 546         if (handler != NULL) {
 547                 (*handler)(buf, nb, autopoll);
 548                 wmb();
 549                 adb_handler[id].busy = 0;
 550         }
 551
 552 }
 553
 554 /* Try to change handler to new_id. Will return 1 if successful. */
 555 static int try_handler_change(int address, int new_id)
 556 {
 557         struct adb_request req;
 558
 559         if (adb_handler[address].handler_id == new_id)
 560             return 1;
 561         adb_request(&req, NULL, ADBREQ_SYNC, 3,
 562             ADB_WRITEREG(address, 3), address | 0x20, new_id);
 563         adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 564             ADB_READREG(address, 3));
 565         if (req.reply_len < 2)
 566             return 0;
 567         if (req.reply[2] != new_id)
 568             return 0;
 569         adb_handler[address].handler_id = req.reply[2];
 570
 571         return 1;
 572 }
 573
 574 int
 575 adb_try_handler_change(int address, int new_id)
 576 {
 577         int ret;
 578
 579         mutex_lock(&adb_handler_mutex);
 580         ret = try_handler_change(address, new_id);
 581         mutex_unlock(&adb_handler_mutex);
 582         return ret;
 583 }
 584 EXPORT_SYMBOL(adb_try_handler_change);
 585
 586 int
 587 adb_get_infos(int address, int *original_address, int *handler_id)
 588 {
 589         mutex_lock(&adb_handler_mutex);
 590         *original_address = adb_handler[address].original_address;
 591         *handler_id = adb_handler[address].handler_id;
 592         mutex_unlock(&adb_handler_mutex);
 593
 594         return (*original_address != 0);
 595 }
 596
 597
 598 /*
 599  * /dev/adb device driver.
 600  */
 601
 602 #define ADB_MAJOR       56      /* major number for /dev/adb */
 603
 604 struct adbdev_state {
 605         spinlock_t      lock;
 606         atomic_t        n_pending;
 607         struct adb_request *completed;
 608         wait_queue_head_t wait_queue;
 609         int             inuse;
 610 };
 611
 612 static void adb_write_done(struct adb_request *req)
 613 {
 614         struct adbdev_state *state = (struct adbdev_state *) req->arg;
 615         unsigned long flags;
 616
 617         if (!req->complete) {
 618                 req->reply_len = 0;
 619                 req->complete = 1;
 620         }
 621         spin_lock_irqsave(&state->lock, flags);
 622         atomic_dec(&state->n_pending);
 623         if (!state->inuse) {
 624                 kfree(req);
 625                 if (atomic_read(&state->n_pending) == 0) {
 626                         spin_unlock_irqrestore(&state->lock, flags);
 627                         kfree(state);
 628                         return;
 629                 }
 630         } else {
 631                 struct adb_request **ap = &state->completed;
 632                 while (*ap != NULL)
 633                         ap = &(*ap)->next;
 634                 req->next = NULL;
 635                 *ap = req;
 636                 wake_up_interruptible(&state->wait_queue);
 637         }
 638         spin_unlock_irqrestore(&state->lock, flags);
 639 }
 640
 641 static int
 642 do_adb_query(struct adb_request *req)
 643 {
 644         int     ret = -EINVAL;
 645
 646         switch(req->data[1]) {
 647         case ADB_QUERY_GETDEVINFO:
 648                 if (req->nbytes < 3)
 649                         break;
 650                 mutex_lock(&adb_handler_mutex);
 651                 req->reply[0] = adb_handler[req->data[2]].original_address;
 652                 req->reply[1] = adb_handler[req->data[2]].handler_id;
 653                 mutex_unlock(&adb_handler_mutex);
 654                 req->complete = 1;
 655                 req->reply_len = 2;
 656                 adb_write_done(req);
 657                 ret = 0;
 658                 break;
 659         }
 660         return ret;
 661 }
 662
 663 static int adb_open(struct inode *inode, struct file *file)
 664 {
 665         struct adbdev_state *state;
 666         int ret = 0;
 667
 668         mutex_lock(&adb_mutex);
 669         if (iminor(inode) > 0 || adb_controller == NULL) {
 670                 ret = -ENXIO;
 671                 goto out;
 672         }
 673         state = kmalloc(sizeof(struct adbdev_state), GFP_KERNEL);
 674         if (state == 0) {
 675                 ret = -ENOMEM;
 676                 goto out;
 677         }
 678         file->private_data = state;
 679         spin_lock_init(&state->lock);
 680         atomic_set(&state->n_pending, 0);
 681         state->completed = NULL;
 682         init_waitqueue_head(&state->wait_queue);
 683         state->inuse = 1;
 684
 685 out:
 686         mutex_unlock(&adb_mutex);
 687         return ret;
 688 }
 689
 690 static int adb_release(struct inode *inode, struct file *file)
 691 {
 692         struct adbdev_state *state = file->private_data;
 693         unsigned long flags;
 694
 695         mutex_lock(&adb_mutex);
 696         if (state) {
 697                 file->private_data = NULL;
 698                 spin_lock_irqsave(&state->lock, flags);
 699                 if (atomic_read(&state->n_pending) == 0
 700                     && state->completed == NULL) {
 701                         spin_unlock_irqrestore(&state->lock, flags);
 702                         kfree(state);
 703                 } else {
 704                         state->inuse = 0;
 705                         spin_unlock_irqrestore(&state->lock, flags);
 706                 }
 707         }
 708         mutex_unlock(&adb_mutex);
 709         return 0;
 710 }
 711
 712 static ssize_t adb_read(struct file *file, char __user *buf,
 713                         size_t count, loff_t *ppos)
 714 {
 715         int ret = 0;
 716         struct adbdev_state *state = file->private_data;
 717         struct adb_request *req;
 718         DECLARE_WAITQUEUE(wait, current);
 719         unsigned long flags;
 720
 721         if (count < 2)
 722                 return -EINVAL;
 723         if (count > sizeof(req->reply))
 724                 count = sizeof(req->reply);
 725
 726         req = NULL;
 727         spin_lock_irqsave(&state->lock, flags);
 728         add_wait_queue(&state->wait_queue, &wait);
 729         set_current_state(TASK_INTERRUPTIBLE);
 730
 731         for (;;) {
 732                 req = state->completed;
 733                 if (req != NULL)
 734                         state->completed = req->next;
 735                 else if (atomic_read(&state->n_pending) == 0)
 736                         ret = -EIO;
 737                 if (req != NULL || ret != 0)
 738                         break;
 739
 740                 if (file->f_flags & O_NONBLOCK) {
 741                         ret = -EAGAIN;
 742                         break;
 743                 }
 744                 if (signal_pending(current)) {
 745                         ret = -ERESTARTSYS;
 746                         break;
 747                 }
 748                 spin_unlock_irqrestore(&state->lock, flags);
 749                 schedule();
 750                 spin_lock_irqsave(&state->lock, flags);
 751         }
 752
 753         set_current_state(TASK_RUNNING);
 754         remove_wait_queue(&state->wait_queue, &wait);
 755         spin_unlock_irqrestore(&state->lock, flags);
 756
 757         if (ret)
 758                 return ret;
 759
 760         ret = req->reply_len;
 761         if (ret > count)
 762                 ret = count;
 763         if (ret > 0 && copy_to_user(buf, req->reply, ret))
 764                 ret = -EFAULT;
 765
 766         kfree(req);
 767         return ret;
 768 }
 769
 770 static ssize_t adb_write(struct file *file, const char __user *buf,
 771                          size_t count, loff_t *ppos)
 772 {
 773         int ret/*, i*/;
 774         struct adbdev_state *state = file->private_data;
 775         struct adb_request *req;
 776
 777         if (count < 2 || count > sizeof(req->data))
 778                 return -EINVAL;
 779         if (adb_controller == NULL)
 780                 return -ENXIO;
 781
 782         req = kmalloc(sizeof(struct adb_request),
 783                                              GFP_KERNEL);
 784         if (req == NULL)
 785                 return -ENOMEM;
 786
 787         req->nbytes = count;
 788         req->done = adb_write_done;
 789         req->arg = (void *) state;
 790         req->complete = 0;
 791
 792         ret = -EFAULT;
 793         if (copy_from_user(req->data, buf, count))
 794                 goto out;
 795
 796         atomic_inc(&state->n_pending);
 797
 798         /* If a probe is in progress or we are sleeping, wait for it to complete */
 799         down(&adb_probe_mutex);
 800
 801         /* Queries are special requests sent to the ADB driver itself */
 802         if (req->data[0] == ADB_QUERY) {
 803                 if (count > 1)
 804                         ret = do_adb_query(req);
 805                 else
 806                         ret = -EINVAL;
 807                 up(&adb_probe_mutex);
 808         }
 809         /* Special case for ADB_BUSRESET request, all others are sent to
 810            the controller */
 811         else if ((req->data[0] == ADB_PACKET) && (count > 1)
 812                 && (req->data[1] == ADB_BUSRESET)) {
 813                 ret = do_adb_reset_bus();
 814                 up(&adb_probe_mutex);
 815                 atomic_dec(&state->n_pending);
 816                 if (ret == 0)
 817                         ret = count;
 818                 goto out;
 819         } else {
 820                 req->reply_expected = ((req->data[1] & 0xc) == 0xc);
 821                 if (adb_controller && adb_controller->send_request)
 822                         ret = adb_controller->send_request(req, 0);
 823                 else
 824                         ret = -ENXIO;
 825                 up(&adb_probe_mutex);
 826         }
 827
 828         if (ret != 0) {
 829                 atomic_dec(&state->n_pending);
 830                 goto out;
 831         }
 832         return count;
 833
 834 out:
 835         kfree(req);
 836         return ret;
 837 }
 838
 839 static const struct file_operations adb_fops = {
 840         .owner          = THIS_MODULE,
 841         .llseek         = no_llseek,
 842         .read           = adb_read,
 843         .write          = adb_write,
 844         .open           = adb_open,
 845         .release        = adb_release,
 846 };
 847
 848 #ifdef CONFIG_PM
 849 static const struct dev_pm_ops adb_dev_pm_ops = {
 850         .suspend = adb_suspend,
 851         .resume = adb_resume,
 852         /* Hibernate hooks */
 853         .freeze = adb_freeze,
 854         .thaw = adb_resume,
 855         .poweroff = adb_poweroff,
 856         .restore = adb_resume,
 857 };
 858 #endif
 859
 860 static struct platform_driver adb_pfdrv = {
 861         .driver = {
 862                 .name = "adb",
 863 #ifdef CONFIG_PM
 864                 .pm = &adb_dev_pm_ops,
 865 #endif
 866         },
 867 };
 868
 869 static struct platform_device adb_pfdev = {
 870         .name = "adb",
 871 };
 872
 873 static int __init
 874 adb_dummy_probe(struct platform_device *dev)
 875 {
 876         if (dev == &adb_pfdev)
 877                 return 0;
 878         return -ENODEV;
 879 }
 880
 881 static void __init
 882 adbdev_init(void)
 883 {
 884         if (register_chrdev(ADB_MAJOR, "adb", &adb_fops)) {
 885                 pr_err("adb: unable to get major %d\n", ADB_MAJOR);
 886                 return;
 887         }
 888
 889         adb_dev_class = class_create(THIS_MODULE, "adb");
 890         if (IS_ERR(adb_dev_class))
 891                 return;
 892         device_create(adb_dev_class, NULL, MKDEV(ADB_MAJOR, 0), NULL, "adb");
 893
 894         platform_device_register(&adb_pfdev);
 895         platform_driver_probe(&adb_pfdrv, adb_dummy_probe);
 896 }