git.oblomov.eu Git - linux-2.6/blob - 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/smp_lock.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 <asm/uaccess.h>
  43 #ifdef CONFIG_PPC
  44 #include <asm/prom.h>
  45 #include <asm/machdep.h>
  46 #endif
  47
  48
  49 EXPORT_SYMBOL(adb_controller);
  50 EXPORT_SYMBOL(adb_client_list);
  51
  52 extern struct adb_driver via_macii_driver;
  53 extern struct adb_driver via_maciisi_driver;
  54 extern struct adb_driver via_cuda_driver;
  55 extern struct adb_driver adb_iop_driver;
  56 extern struct adb_driver via_pmu_driver;
  57 extern struct adb_driver macio_adb_driver;
  58
  59 static struct adb_driver *adb_driver_list[] = {
  60 #ifdef CONFIG_ADB_MACII
  61         &via_macii_driver,
  62 #endif
  63 #ifdef CONFIG_ADB_MACIISI
  64         &via_maciisi_driver,
  65 #endif
  66 #ifdef CONFIG_ADB_CUDA
  67         &via_cuda_driver,
  68 #endif
  69 #ifdef CONFIG_ADB_IOP
  70         &adb_iop_driver,
  71 #endif
  72 #if defined(CONFIG_ADB_PMU) || defined(CONFIG_ADB_PMU68K)
  73         &via_pmu_driver,
  74 #endif
  75 #ifdef CONFIG_ADB_MACIO
  76         &macio_adb_driver,
  77 #endif
  78         NULL
  79 };
  80
  81 static struct class *adb_dev_class;
  82
  83 struct adb_driver *adb_controller;
  84 BLOCKING_NOTIFIER_HEAD(adb_client_list);
  85 static int adb_got_sleep;
  86 static int adb_inited;
  87 static DECLARE_MUTEX(adb_probe_mutex);
  88 static int sleepy_trackpad;
  89 static int autopoll_devs;
  90 int __adb_probe_sync;
  91
  92 static int adb_scan_bus(void);
  93 static int do_adb_reset_bus(void);
  94 static void adbdev_init(void);
  95 static int try_handler_change(int, int);
  96
  97 static struct adb_handler {
  98         void (*handler)(unsigned char *, int, int);
  99         int original_address;
 100         int handler_id;
 101         int busy;
 102 } adb_handler[16];
 103
 104 /*
 105  * The adb_handler_mutex mutex protects all accesses to the original_address
 106  * and handler_id fields of adb_handler[i] for all i, and changes to the
 107  * handler field.
 108  * Accesses to the handler field are protected by the adb_handler_lock
 109  * rwlock.  It is held across all calls to any handler, so that by the
 110  * time adb_unregister returns, we know that the old handler isn't being
 111  * called.
 112  */
 113 static DEFINE_MUTEX(adb_handler_mutex);
 114 static DEFINE_RWLOCK(adb_handler_lock);
 115
 116 #if 0
 117 static void printADBreply(struct adb_request *req)
 118 {
 119         int i;
 120
 121         printk("adb reply (%d)", req->reply_len);
 122         for(i = 0; i < req->reply_len; i++)
 123                 printk(" %x", req->reply[i]);
 124         printk("\n");
 125
 126 }
 127 #endif
 128
 129 static int adb_scan_bus(void)
 130 {
 131         int i, highFree=0, noMovement;
 132         int devmask = 0;
 133         struct adb_request req;
 134
 135         /* assumes adb_handler[] is all zeroes at this point */
 136         for (i = 1; i < 16; i++) {
 137                 /* see if there is anything at address i */
 138                 adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 139                             (i << 4) | 0xf);
 140                 if (req.reply_len > 1)
 141                         /* one or more devices at this address */
 142                         adb_handler[i].original_address = i;
 143                 else if (i > highFree)
 144                         highFree = i;
 145         }
 146
 147         /* Note we reset noMovement to 0 each time we move a device */
 148         for (noMovement = 1; noMovement < 2 && highFree > 0; noMovement++) {
 149                 for (i = 1; i < 16; i++) {
 150                         if (adb_handler[i].original_address == 0)
 151                                 continue;
 152                         /*
 153                          * Send a "talk register 3" command to address i
 154                          * to provoke a collision if there is more than
 155                          * one device at this address.
 156                          */
 157                         adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 158                                     (i << 4) | 0xf);
 159                         /*
 160                          * Move the device(s) which didn't detect a
 161                          * collision to address `highFree'.  Hopefully
 162                          * this only moves one device.
 163                          */
 164                         adb_request(&req, NULL, ADBREQ_SYNC, 3,
 165                                     (i<< 4) | 0xb, (highFree | 0x60), 0xfe);
 166                         /*
 167                          * See if anybody actually moved. This is suggested
 168                          * by HW TechNote 01:
 169                          *
 170                          * http://developer.apple.com/technotes/hw/hw_01.html
 171                          */
 172                         adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 173                                     (highFree << 4) | 0xf);
 174                         if (req.reply_len <= 1) continue;
 175                         /*
 176                          * Test whether there are any device(s) left
 177                          * at address i.
 178                          */
 179                         adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 180                                     (i << 4) | 0xf);
 181                         if (req.reply_len > 1) {
 182                                 /*
 183                                  * There are still one or more devices
 184                                  * left at address i.  Register the one(s)
 185                                  * we moved to `highFree', and find a new
 186                                  * value for highFree.
 187                                  */
 188                                 adb_handler[highFree].original_address =
 189                                         adb_handler[i].original_address;
 190                                 while (highFree > 0 &&
 191                                        adb_handler[highFree].original_address)
 192                                         highFree--;
 193                                 if (highFree <= 0)
 194                                         break;
 195
 196                                 noMovement = 0;
 197                         }
 198                         else {
 199                                 /*
 200                                  * No devices left at address i; move the
 201                                  * one(s) we moved to `highFree' back to i.
 202                                  */
 203                                 adb_request(&req, NULL, ADBREQ_SYNC, 3,
 204                                             (highFree << 4) | 0xb,
 205                                             (i | 0x60), 0xfe);
 206                         }
 207                 }
 208         }
 209
 210         /* Now fill in the handler_id field of the adb_handler entries. */
 211         printk(KERN_DEBUG "adb devices:");
 212         for (i = 1; i < 16; i++) {
 213                 if (adb_handler[i].original_address == 0)
 214                         continue;
 215                 adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 216                             (i << 4) | 0xf);
 217                 adb_handler[i].handler_id = req.reply[2];
 218                 printk(" [%d]: %d %x", i, adb_handler[i].original_address,
 219                        adb_handler[i].handler_id);
 220                 devmask |= 1 << i;
 221         }
 222         printk("\n");
 223         return devmask;
 224 }
 225
 226 /*
 227  * This kernel task handles ADB probing. It dies once probing is
 228  * completed.
 229  */
 230 static int
 231 adb_probe_task(void *x)
 232 {
 233         printk(KERN_INFO "adb: starting probe task...\n");
 234         do_adb_reset_bus();
 235         printk(KERN_INFO "adb: finished probe task...\n");
 236
 237         up(&adb_probe_mutex);
 238
 239         return 0;
 240 }
 241
 242 static void
 243 __adb_probe_task(struct work_struct *bullshit)
 244 {
 245         kthread_run(adb_probe_task, NULL, "kadbprobe");
 246 }
 247
 248 static DECLARE_WORK(adb_reset_work, __adb_probe_task);
 249
 250 int
 251 adb_reset_bus(void)
 252 {
 253         if (__adb_probe_sync) {
 254                 do_adb_reset_bus();
 255                 return 0;
 256         }
 257
 258         down(&adb_probe_mutex);
 259         schedule_work(&adb_reset_work);
 260         return 0;
 261 }
 262
 263 #ifdef CONFIG_PM
 264 /*
 265  * notify clients before sleep
 266  */
 267 static int adb_suspend(struct platform_device *dev, pm_message_t state)
 268 {
 269         adb_got_sleep = 1;
 270         /* We need to get a lock on the probe thread */
 271         down(&adb_probe_mutex);
 272         /* Stop autopoll */
 273         if (adb_controller->autopoll)
 274                 adb_controller->autopoll(0);
 275         blocking_notifier_call_chain(&adb_client_list, ADB_MSG_POWERDOWN, NULL);
 276
 277         return 0;
 278 }
 279
 280 /*
 281  * reset bus after sleep
 282  */
 283 static int adb_resume(struct platform_device *dev)
 284 {
 285         adb_got_sleep = 0;
 286         up(&adb_probe_mutex);
 287         adb_reset_bus();
 288
 289         return 0;
 290 }
 291 #endif /* CONFIG_PM */
 292
 293 int __init adb_init(void)
 294 {
 295         struct adb_driver *driver;
 296         int i;
 297
 298 #ifdef CONFIG_PPC32
 299         if (!machine_is(chrp) && !machine_is(powermac))
 300                 return 0;
 301 #endif
 302 #ifdef CONFIG_MAC
 303         if (!MACH_IS_MAC)
 304                 return 0;
 305 #endif
 306
 307         /* xmon may do early-init */
 308         if (adb_inited)
 309                 return 0;
 310         adb_inited = 1;
 311
 312         adb_controller = NULL;
 313
 314         i = 0;
 315         while ((driver = adb_driver_list[i++]) != NULL) {
 316                 if (!driver->probe()) {
 317                         adb_controller = driver;
 318                         break;
 319                 }
 320         }
 321         if ((adb_controller == NULL) || adb_controller->init()) {
 322                 printk(KERN_WARNING "Warning: no ADB interface detected\n");
 323                 adb_controller = NULL;
 324         } else {
 325 #ifdef CONFIG_PPC
 326                 if (machine_is_compatible("AAPL,PowerBook1998") ||
 327                         machine_is_compatible("PowerBook1,1"))
 328                         sleepy_trackpad = 1;
 329 #endif /* CONFIG_PPC */
 330
 331                 adbdev_init();
 332                 adb_reset_bus();
 333         }
 334         return 0;
 335 }
 336
 337 device_initcall(adb_init);
 338
 339 static int
 340 do_adb_reset_bus(void)
 341 {
 342         int ret;
 343
 344         if (adb_controller == NULL)
 345                 return -ENXIO;
 346
 347         if (adb_controller->autopoll)
 348                 adb_controller->autopoll(0);
 349
 350         blocking_notifier_call_chain(&adb_client_list,
 351                 ADB_MSG_PRE_RESET, NULL);
 352
 353         if (sleepy_trackpad) {
 354                 /* Let the trackpad settle down */
 355                 msleep(500);
 356         }
 357
 358         mutex_lock(&adb_handler_mutex);
 359         write_lock_irq(&adb_handler_lock);
 360         memset(adb_handler, 0, sizeof(adb_handler));
 361         write_unlock_irq(&adb_handler_lock);
 362
 363         /* That one is still a bit synchronous, oh well... */
 364         if (adb_controller->reset_bus)
 365                 ret = adb_controller->reset_bus();
 366         else
 367                 ret = 0;
 368
 369         if (sleepy_trackpad) {
 370                 /* Let the trackpad settle down */
 371                 msleep(1500);
 372         }
 373
 374         if (!ret) {
 375                 autopoll_devs = adb_scan_bus();
 376                 if (adb_controller->autopoll)
 377                         adb_controller->autopoll(autopoll_devs);
 378         }
 379         mutex_unlock(&adb_handler_mutex);
 380
 381         blocking_notifier_call_chain(&adb_client_list,
 382                 ADB_MSG_POST_RESET, NULL);
 383
 384         return ret;
 385 }
 386
 387 void
 388 adb_poll(void)
 389 {
 390         if ((adb_controller == NULL)||(adb_controller->poll == NULL))
 391                 return;
 392         adb_controller->poll();
 393 }
 394
 395 static void adb_sync_req_done(struct adb_request *req)
 396 {
 397         struct completion *comp = req->arg;
 398
 399         complete(comp);
 400 }
 401
 402 int
 403 adb_request(struct adb_request *req, void (*done)(struct adb_request *),
 404             int flags, int nbytes, ...)
 405 {
 406         va_list list;
 407         int i;
 408         int rc;
 409         struct completion comp;
 410
 411         if ((adb_controller == NULL) || (adb_controller->send_request == NULL))
 412                 return -ENXIO;
 413         if (nbytes < 1)
 414                 return -EINVAL;
 415
 416         req->nbytes = nbytes+1;
 417         req->done = done;
 418         req->reply_expected = flags & ADBREQ_REPLY;
 419         req->data[0] = ADB_PACKET;
 420         va_start(list, nbytes);
 421         for (i = 0; i < nbytes; ++i)
 422                 req->data[i+1] = va_arg(list, int);
 423         va_end(list);
 424
 425         if (flags & ADBREQ_NOSEND)
 426                 return 0;
 427
 428         /* Synchronous requests block using an on-stack completion */
 429         if (flags & ADBREQ_SYNC) {
 430                 WARN_ON(done);
 431                 req->done = adb_sync_req_done;
 432                 req->arg = &comp;
 433                 init_completion(&comp);
 434         }
 435
 436         rc = adb_controller->send_request(req, 0);
 437
 438         if ((flags & ADBREQ_SYNC) && !rc && !req->complete)
 439                 wait_for_completion(&comp);
 440
 441         return rc;
 442 }
 443
 444  /* Ultimately this should return the number of devices with
 445     the given default id.
 446     And it does it now ! Note: changed behaviour: This function
 447     will now register if default_id _and_ handler_id both match
 448     but handler_id can be left to 0 to match with default_id only.
 449     When handler_id is set, this function will try to adjust
 450     the handler_id id it doesn't match. */
 451 int
 452 adb_register(int default_id, int handler_id, struct adb_ids *ids,
 453              void (*handler)(unsigned char *, int, int))
 454 {
 455         int i;
 456
 457         mutex_lock(&adb_handler_mutex);
 458         ids->nids = 0;
 459         for (i = 1; i < 16; i++) {
 460                 if ((adb_handler[i].original_address == default_id) &&
 461                     (!handler_id || (handler_id == adb_handler[i].handler_id) ||
 462                     try_handler_change(i, handler_id))) {
 463                         if (adb_handler[i].handler != 0) {
 464                                 printk(KERN_ERR
 465                                        "Two handlers for ADB device %d\n",
 466                                        default_id);
 467                                 continue;
 468                         }
 469                         write_lock_irq(&adb_handler_lock);
 470                         adb_handler[i].handler = handler;
 471                         write_unlock_irq(&adb_handler_lock);
 472                         ids->id[ids->nids++] = i;
 473                 }
 474         }
 475         mutex_unlock(&adb_handler_mutex);
 476         return ids->nids;
 477 }
 478
 479 int
 480 adb_unregister(int index)
 481 {
 482         int ret = -ENODEV;
 483
 484         mutex_lock(&adb_handler_mutex);
 485         write_lock_irq(&adb_handler_lock);
 486         if (adb_handler[index].handler) {
 487                 while(adb_handler[index].busy) {
 488                         write_unlock_irq(&adb_handler_lock);
 489                         yield();
 490                         write_lock_irq(&adb_handler_lock);
 491                 }
 492                 ret = 0;
 493                 adb_handler[index].handler = NULL;
 494         }
 495         write_unlock_irq(&adb_handler_lock);
 496         mutex_unlock(&adb_handler_mutex);
 497         return ret;
 498 }
 499
 500 void
 501 adb_input(unsigned char *buf, int nb, int autopoll)
 502 {
 503         int i, id;
 504         static int dump_adb_input = 0;
 505         unsigned long flags;
 506
 507         void (*handler)(unsigned char *, int, int);
 508
 509         /* We skip keystrokes and mouse moves when the sleep process
 510          * has been started. We stop autopoll, but this is another security
 511          */
 512         if (adb_got_sleep)
 513                 return;
 514
 515         id = buf[0] >> 4;
 516         if (dump_adb_input) {
 517                 printk(KERN_INFO "adb packet: ");
 518                 for (i = 0; i < nb; ++i)
 519                         printk(" %x", buf[i]);
 520                 printk(", id = %d\n", id);
 521         }
 522         write_lock_irqsave(&adb_handler_lock, flags);
 523         handler = adb_handler[id].handler;
 524         if (handler != NULL)
 525                 adb_handler[id].busy = 1;
 526         write_unlock_irqrestore(&adb_handler_lock, flags);
 527         if (handler != NULL) {
 528                 (*handler)(buf, nb, autopoll);
 529                 wmb();
 530                 adb_handler[id].busy = 0;
 531         }
 532
 533 }
 534
 535 /* Try to change handler to new_id. Will return 1 if successful. */
 536 static int try_handler_change(int address, int new_id)
 537 {
 538         struct adb_request req;
 539
 540         if (adb_handler[address].handler_id == new_id)
 541             return 1;
 542         adb_request(&req, NULL, ADBREQ_SYNC, 3,
 543             ADB_WRITEREG(address, 3), address | 0x20, new_id);
 544         adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 545             ADB_READREG(address, 3));
 546         if (req.reply_len < 2)
 547             return 0;
 548         if (req.reply[2] != new_id)
 549             return 0;
 550         adb_handler[address].handler_id = req.reply[2];
 551
 552         return 1;
 553 }
 554
 555 int
 556 adb_try_handler_change(int address, int new_id)
 557 {
 558         int ret;
 559
 560         mutex_lock(&adb_handler_mutex);
 561         ret = try_handler_change(address, new_id);
 562         mutex_unlock(&adb_handler_mutex);
 563         return ret;
 564 }
 565
 566 int
 567 adb_get_infos(int address, int *original_address, int *handler_id)
 568 {
 569         mutex_lock(&adb_handler_mutex);
 570         *original_address = adb_handler[address].original_address;
 571         *handler_id = adb_handler[address].handler_id;
 572         mutex_unlock(&adb_handler_mutex);
 573
 574         return (*original_address != 0);
 575 }
 576
 577
 578 /*
 579  * /dev/adb device driver.
 580  */
 581
 582 #define ADB_MAJOR       56      /* major number for /dev/adb */
 583
 584 struct adbdev_state {
 585         spinlock_t      lock;
 586         atomic_t        n_pending;
 587         struct adb_request *completed;
 588         wait_queue_head_t wait_queue;
 589         int             inuse;
 590 };
 591
 592 static void adb_write_done(struct adb_request *req)
 593 {
 594         struct adbdev_state *state = (struct adbdev_state *) req->arg;
 595         unsigned long flags;
 596
 597         if (!req->complete) {
 598                 req->reply_len = 0;
 599                 req->complete = 1;
 600         }
 601         spin_lock_irqsave(&state->lock, flags);
 602         atomic_dec(&state->n_pending);
 603         if (!state->inuse) {
 604                 kfree(req);
 605                 if (atomic_read(&state->n_pending) == 0) {
 606                         spin_unlock_irqrestore(&state->lock, flags);
 607                         kfree(state);
 608                         return;
 609                 }
 610         } else {
 611                 struct adb_request **ap = &state->completed;
 612                 while (*ap != NULL)
 613                         ap = &(*ap)->next;
 614                 req->next = NULL;
 615                 *ap = req;
 616                 wake_up_interruptible(&state->wait_queue);
 617         }
 618         spin_unlock_irqrestore(&state->lock, flags);
 619 }
 620
 621 static int
 622 do_adb_query(struct adb_request *req)
 623 {
 624         int     ret = -EINVAL;
 625
 626         switch(req->data[1])
 627         {
 628         case ADB_QUERY_GETDEVINFO:
 629                 if (req->nbytes < 3)
 630                         break;
 631                 mutex_lock(&adb_handler_mutex);
 632                 req->reply[0] = adb_handler[req->data[2]].original_address;
 633                 req->reply[1] = adb_handler[req->data[2]].handler_id;
 634                 mutex_unlock(&adb_handler_mutex);
 635                 req->complete = 1;
 636                 req->reply_len = 2;
 637                 adb_write_done(req);
 638                 ret = 0;
 639                 break;
 640         }
 641         return ret;
 642 }
 643
 644 static int adb_open(struct inode *inode, struct file *file)
 645 {
 646         struct adbdev_state *state;
 647
 648         if (iminor(inode) > 0 || adb_controller == NULL)
 649                 return -ENXIO;
 650         state = kmalloc(sizeof(struct adbdev_state), GFP_KERNEL);
 651         if (state == 0)
 652                 return -ENOMEM;
 653         file->private_data = state;
 654         spin_lock_init(&state->lock);
 655         atomic_set(&state->n_pending, 0);
 656         state->completed = NULL;
 657         init_waitqueue_head(&state->wait_queue);
 658         state->inuse = 1;
 659
 660         return 0;
 661 }
 662
 663 static int adb_release(struct inode *inode, struct file *file)
 664 {
 665         struct adbdev_state *state = file->private_data;
 666         unsigned long flags;
 667
 668         lock_kernel();
 669         if (state) {
 670                 file->private_data = NULL;
 671                 spin_lock_irqsave(&state->lock, flags);
 672                 if (atomic_read(&state->n_pending) == 0
 673                     && state->completed == NULL) {
 674                         spin_unlock_irqrestore(&state->lock, flags);
 675                         kfree(state);
 676                 } else {
 677                         state->inuse = 0;
 678                         spin_unlock_irqrestore(&state->lock, flags);
 679                 }
 680         }
 681         unlock_kernel();
 682         return 0;
 683 }
 684
 685 static ssize_t adb_read(struct file *file, char __user *buf,
 686                         size_t count, loff_t *ppos)
 687 {
 688         int ret = 0;
 689         struct adbdev_state *state = file->private_data;
 690         struct adb_request *req;
 691         wait_queue_t wait = __WAITQUEUE_INITIALIZER(wait,current);
 692         unsigned long flags;
 693
 694         if (count < 2)
 695                 return -EINVAL;
 696         if (count > sizeof(req->reply))
 697                 count = sizeof(req->reply);
 698         if (!access_ok(VERIFY_WRITE, buf, count))
 699                 return -EFAULT;
 700
 701         req = NULL;
 702         spin_lock_irqsave(&state->lock, flags);
 703         add_wait_queue(&state->wait_queue, &wait);
 704         current->state = TASK_INTERRUPTIBLE;
 705
 706         for (;;) {
 707                 req = state->completed;
 708                 if (req != NULL)
 709                         state->completed = req->next;
 710                 else if (atomic_read(&state->n_pending) == 0)
 711                         ret = -EIO;
 712                 if (req != NULL || ret != 0)
 713                         break;
 714
 715                 if (file->f_flags & O_NONBLOCK) {
 716                         ret = -EAGAIN;
 717                         break;
 718                 }
 719                 if (signal_pending(current)) {
 720                         ret = -ERESTARTSYS;
 721                         break;
 722                 }
 723                 spin_unlock_irqrestore(&state->lock, flags);
 724                 schedule();
 725                 spin_lock_irqsave(&state->lock, flags);
 726         }
 727
 728         current->state = TASK_RUNNING;
 729         remove_wait_queue(&state->wait_queue, &wait);
 730         spin_unlock_irqrestore(&state->lock, flags);
 731
 732         if (ret)
 733                 return ret;
 734
 735         ret = req->reply_len;
 736         if (ret > count)
 737                 ret = count;
 738         if (ret > 0 && copy_to_user(buf, req->reply, ret))
 739                 ret = -EFAULT;
 740
 741         kfree(req);
 742         return ret;
 743 }
 744
 745 static ssize_t adb_write(struct file *file, const char __user *buf,
 746                          size_t count, loff_t *ppos)
 747 {
 748         int ret/*, i*/;
 749         struct adbdev_state *state = file->private_data;
 750         struct adb_request *req;
 751
 752         if (count < 2 || count > sizeof(req->data))
 753                 return -EINVAL;
 754         if (adb_controller == NULL)
 755                 return -ENXIO;
 756         if (!access_ok(VERIFY_READ, buf, count))
 757                 return -EFAULT;
 758
 759         req = kmalloc(sizeof(struct adb_request),
 760                                              GFP_KERNEL);
 761         if (req == NULL)
 762                 return -ENOMEM;
 763
 764         req->nbytes = count;
 765         req->done = adb_write_done;
 766         req->arg = (void *) state;
 767         req->complete = 0;
 768
 769         ret = -EFAULT;
 770         if (copy_from_user(req->data, buf, count))
 771                 goto out;
 772
 773         atomic_inc(&state->n_pending);
 774
 775         /* If a probe is in progress or we are sleeping, wait for it to complete */
 776         down(&adb_probe_mutex);
 777
 778         /* Queries are special requests sent to the ADB driver itself */
 779         if (req->data[0] == ADB_QUERY) {
 780                 if (count > 1)
 781                         ret = do_adb_query(req);
 782                 else
 783                         ret = -EINVAL;
 784                 up(&adb_probe_mutex);
 785         }
 786         /* Special case for ADB_BUSRESET request, all others are sent to
 787            the controller */
 788         else if ((req->data[0] == ADB_PACKET)&&(count > 1)
 789                 &&(req->data[1] == ADB_BUSRESET)) {
 790                 ret = do_adb_reset_bus();
 791                 up(&adb_probe_mutex);
 792                 atomic_dec(&state->n_pending);
 793                 if (ret == 0)
 794                         ret = count;
 795                 goto out;
 796         } else {
 797                 req->reply_expected = ((req->data[1] & 0xc) == 0xc);
 798                 if (adb_controller && adb_controller->send_request)
 799                         ret = adb_controller->send_request(req, 0);
 800                 else
 801                         ret = -ENXIO;
 802                 up(&adb_probe_mutex);
 803         }
 804
 805         if (ret != 0) {
 806                 atomic_dec(&state->n_pending);
 807                 goto out;
 808         }
 809         return count;
 810
 811 out:
 812         kfree(req);
 813         return ret;
 814 }
 815
 816 static const struct file_operations adb_fops = {
 817         .owner          = THIS_MODULE,
 818         .llseek         = no_llseek,
 819         .read           = adb_read,
 820         .write          = adb_write,
 821         .open           = adb_open,
 822         .release        = adb_release,
 823 };
 824
 825 static struct platform_driver adb_pfdrv = {
 826         .driver = {
 827                 .name = "adb",
 828         },
 829 #ifdef CONFIG_PM
 830         .suspend = adb_suspend,
 831         .resume = adb_resume,
 832 #endif
 833 };
 834
 835 static struct platform_device adb_pfdev = {
 836         .name = "adb",
 837 };
 838
 839 static int __init
 840 adb_dummy_probe(struct platform_device *dev)
 841 {
 842         if (dev == &adb_pfdev)
 843                 return 0;
 844         return -ENODEV;
 845 }
 846
 847 static void __init
 848 adbdev_init(void)
 849 {
 850         if (register_chrdev(ADB_MAJOR, "adb", &adb_fops)) {
 851                 printk(KERN_ERR "adb: unable to get major %d\n", ADB_MAJOR);
 852                 return;
 853         }
 854
 855         adb_dev_class = class_create(THIS_MODULE, "adb");
 856         if (IS_ERR(adb_dev_class))
 857                 return;
 858         device_create(adb_dev_class, NULL, MKDEV(ADB_MAJOR, 0), "adb");
 859
 860         platform_device_register(&adb_pfdev);
 861         platform_driver_probe(&adb_pfdrv, adb_dummy_probe);
 862 }