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
  41 #include <asm/uaccess.h>
  42 #include <asm/semaphore.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_sem 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 DECLARE_MUTEX(adb_handler_sem);
 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_PPC64
 303         if (!machine_is(powermac))
 304                 return 0;
 305 #endif
 306 #ifdef CONFIG_MAC
 307         if (!MACH_IS_MAC)
 308                 return 0;
 309 #endif
 310
 311         /* xmon may do early-init */
 312         if (adb_inited)
 313                 return 0;
 314         adb_inited = 1;
 315
 316         adb_controller = NULL;
 317
 318         i = 0;
 319         while ((driver = adb_driver_list[i++]) != NULL) {
 320                 if (!driver->probe()) {
 321                         adb_controller = driver;
 322                         break;
 323                 }
 324         }
 325         if ((adb_controller == NULL) || adb_controller->init()) {
 326                 printk(KERN_WARNING "Warning: no ADB interface detected\n");
 327                 adb_controller = NULL;
 328         } else {
 329 #ifdef CONFIG_PPC
 330                 if (machine_is_compatible("AAPL,PowerBook1998") ||
 331                         machine_is_compatible("PowerBook1,1"))
 332                         sleepy_trackpad = 1;
 333 #endif /* CONFIG_PPC */
 334
 335                 adbdev_init();
 336                 adb_reset_bus();
 337         }
 338         return 0;
 339 }
 340
 341 __initcall(adb_init);
 342
 343 static int
 344 do_adb_reset_bus(void)
 345 {
 346         int ret;
 347
 348         if (adb_controller == NULL)
 349                 return -ENXIO;
 350
 351         if (adb_controller->autopoll)
 352                 adb_controller->autopoll(0);
 353
 354         blocking_notifier_call_chain(&adb_client_list,
 355                 ADB_MSG_PRE_RESET, NULL);
 356
 357         if (sleepy_trackpad) {
 358                 /* Let the trackpad settle down */
 359                 msleep(500);
 360         }
 361
 362         down(&adb_handler_sem);
 363         write_lock_irq(&adb_handler_lock);
 364         memset(adb_handler, 0, sizeof(adb_handler));
 365         write_unlock_irq(&adb_handler_lock);
 366
 367         /* That one is still a bit synchronous, oh well... */
 368         if (adb_controller->reset_bus)
 369                 ret = adb_controller->reset_bus();
 370         else
 371                 ret = 0;
 372
 373         if (sleepy_trackpad) {
 374                 /* Let the trackpad settle down */
 375                 msleep(1500);
 376         }
 377
 378         if (!ret) {
 379                 autopoll_devs = adb_scan_bus();
 380                 if (adb_controller->autopoll)
 381                         adb_controller->autopoll(autopoll_devs);
 382         }
 383         up(&adb_handler_sem);
 384
 385         blocking_notifier_call_chain(&adb_client_list,
 386                 ADB_MSG_POST_RESET, NULL);
 387
 388         return ret;
 389 }
 390
 391 void
 392 adb_poll(void)
 393 {
 394         if ((adb_controller == NULL)||(adb_controller->poll == NULL))
 395                 return;
 396         adb_controller->poll();
 397 }
 398
 399 static void adb_sync_req_done(struct adb_request *req)
 400 {
 401         struct completion *comp = req->arg;
 402
 403         complete(comp);
 404 }
 405
 406 int
 407 adb_request(struct adb_request *req, void (*done)(struct adb_request *),
 408             int flags, int nbytes, ...)
 409 {
 410         va_list list;
 411         int i;
 412         int rc;
 413         struct completion comp;
 414
 415         if ((adb_controller == NULL) || (adb_controller->send_request == NULL))
 416                 return -ENXIO;
 417         if (nbytes < 1)
 418                 return -EINVAL;
 419
 420         req->nbytes = nbytes+1;
 421         req->done = done;
 422         req->reply_expected = flags & ADBREQ_REPLY;
 423         req->data[0] = ADB_PACKET;
 424         va_start(list, nbytes);
 425         for (i = 0; i < nbytes; ++i)
 426                 req->data[i+1] = va_arg(list, int);
 427         va_end(list);
 428
 429         if (flags & ADBREQ_NOSEND)
 430                 return 0;
 431
 432         /* Synchronous requests block using an on-stack completion */
 433         if (flags & ADBREQ_SYNC) {
 434                 WARN_ON(done);
 435                 req->done = adb_sync_req_done;
 436                 req->arg = &comp;
 437                 init_completion(&comp);
 438         }
 439
 440         rc = adb_controller->send_request(req, 0);
 441
 442         if ((flags & ADBREQ_SYNC) && !rc && !req->complete)
 443                 wait_for_completion(&comp);
 444
 445         return rc;
 446 }
 447
 448  /* Ultimately this should return the number of devices with
 449     the given default id.
 450     And it does it now ! Note: changed behaviour: This function
 451     will now register if default_id _and_ handler_id both match
 452     but handler_id can be left to 0 to match with default_id only.
 453     When handler_id is set, this function will try to adjust
 454     the handler_id id it doesn't match. */
 455 int
 456 adb_register(int default_id, int handler_id, struct adb_ids *ids,
 457              void (*handler)(unsigned char *, int, int))
 458 {
 459         int i;
 460
 461         down(&adb_handler_sem);
 462         ids->nids = 0;
 463         for (i = 1; i < 16; i++) {
 464                 if ((adb_handler[i].original_address == default_id) &&
 465                     (!handler_id || (handler_id == adb_handler[i].handler_id) ||
 466                     try_handler_change(i, handler_id))) {
 467                         if (adb_handler[i].handler != 0) {
 468                                 printk(KERN_ERR
 469                                        "Two handlers for ADB device %d\n",
 470                                        default_id);
 471                                 continue;
 472                         }
 473                         write_lock_irq(&adb_handler_lock);
 474                         adb_handler[i].handler = handler;
 475                         write_unlock_irq(&adb_handler_lock);
 476                         ids->id[ids->nids++] = i;
 477                 }
 478         }
 479         up(&adb_handler_sem);
 480         return ids->nids;
 481 }
 482
 483 int
 484 adb_unregister(int index)
 485 {
 486         int ret = -ENODEV;
 487
 488         down(&adb_handler_sem);
 489         write_lock_irq(&adb_handler_lock);
 490         if (adb_handler[index].handler) {
 491                 while(adb_handler[index].busy) {
 492                         write_unlock_irq(&adb_handler_lock);
 493                         yield();
 494                         write_lock_irq(&adb_handler_lock);
 495                 }
 496                 ret = 0;
 497                 adb_handler[index].handler = NULL;
 498         }
 499         write_unlock_irq(&adb_handler_lock);
 500         up(&adb_handler_sem);
 501         return ret;
 502 }
 503
 504 void
 505 adb_input(unsigned char *buf, int nb, int autopoll)
 506 {
 507         int i, id;
 508         static int dump_adb_input = 0;
 509         unsigned long flags;
 510
 511         void (*handler)(unsigned char *, int, int);
 512
 513         /* We skip keystrokes and mouse moves when the sleep process
 514          * has been started. We stop autopoll, but this is another security
 515          */
 516         if (adb_got_sleep)
 517                 return;
 518
 519         id = buf[0] >> 4;
 520         if (dump_adb_input) {
 521                 printk(KERN_INFO "adb packet: ");
 522                 for (i = 0; i < nb; ++i)
 523                         printk(" %x", buf[i]);
 524                 printk(", id = %d\n", id);
 525         }
 526         write_lock_irqsave(&adb_handler_lock, flags);
 527         handler = adb_handler[id].handler;
 528         if (handler != NULL)
 529                 adb_handler[id].busy = 1;
 530         write_unlock_irqrestore(&adb_handler_lock, flags);
 531         if (handler != NULL) {
 532                 (*handler)(buf, nb, autopoll);
 533                 wmb();
 534                 adb_handler[id].busy = 0;
 535         }
 536
 537 }
 538
 539 /* Try to change handler to new_id. Will return 1 if successful. */
 540 static int try_handler_change(int address, int new_id)
 541 {
 542         struct adb_request req;
 543
 544         if (adb_handler[address].handler_id == new_id)
 545             return 1;
 546         adb_request(&req, NULL, ADBREQ_SYNC, 3,
 547             ADB_WRITEREG(address, 3), address | 0x20, new_id);
 548         adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 549             ADB_READREG(address, 3));
 550         if (req.reply_len < 2)
 551             return 0;
 552         if (req.reply[2] != new_id)
 553             return 0;
 554         adb_handler[address].handler_id = req.reply[2];
 555
 556         return 1;
 557 }
 558
 559 int
 560 adb_try_handler_change(int address, int new_id)
 561 {
 562         int ret;
 563
 564         down(&adb_handler_sem);
 565         ret = try_handler_change(address, new_id);
 566         up(&adb_handler_sem);
 567         return ret;
 568 }
 569
 570 int
 571 adb_get_infos(int address, int *original_address, int *handler_id)
 572 {
 573         down(&adb_handler_sem);
 574         *original_address = adb_handler[address].original_address;
 575         *handler_id = adb_handler[address].handler_id;
 576         up(&adb_handler_sem);
 577
 578         return (*original_address != 0);
 579 }
 580
 581
 582 /*
 583  * /dev/adb device driver.
 584  */
 585
 586 #define ADB_MAJOR       56      /* major number for /dev/adb */
 587
 588 struct adbdev_state {
 589         spinlock_t      lock;
 590         atomic_t        n_pending;
 591         struct adb_request *completed;
 592         wait_queue_head_t wait_queue;
 593         int             inuse;
 594 };
 595
 596 static void adb_write_done(struct adb_request *req)
 597 {
 598         struct adbdev_state *state = (struct adbdev_state *) req->arg;
 599         unsigned long flags;
 600
 601         if (!req->complete) {
 602                 req->reply_len = 0;
 603                 req->complete = 1;
 604         }
 605         spin_lock_irqsave(&state->lock, flags);
 606         atomic_dec(&state->n_pending);
 607         if (!state->inuse) {
 608                 kfree(req);
 609                 if (atomic_read(&state->n_pending) == 0) {
 610                         spin_unlock_irqrestore(&state->lock, flags);
 611                         kfree(state);
 612                         return;
 613                 }
 614         } else {
 615                 struct adb_request **ap = &state->completed;
 616                 while (*ap != NULL)
 617                         ap = &(*ap)->next;
 618                 req->next = NULL;
 619                 *ap = req;
 620                 wake_up_interruptible(&state->wait_queue);
 621         }
 622         spin_unlock_irqrestore(&state->lock, flags);
 623 }
 624
 625 static int
 626 do_adb_query(struct adb_request *req)
 627 {
 628         int     ret = -EINVAL;
 629
 630         switch(req->data[1])
 631         {
 632         case ADB_QUERY_GETDEVINFO:
 633                 if (req->nbytes < 3)
 634                         break;
 635                 down(&adb_handler_sem);
 636                 req->reply[0] = adb_handler[req->data[2]].original_address;
 637                 req->reply[1] = adb_handler[req->data[2]].handler_id;
 638                 up(&adb_handler_sem);
 639                 req->complete = 1;
 640                 req->reply_len = 2;
 641                 adb_write_done(req);
 642                 ret = 0;
 643                 break;
 644         }
 645         return ret;
 646 }
 647
 648 static int adb_open(struct inode *inode, struct file *file)
 649 {
 650         struct adbdev_state *state;
 651
 652         if (iminor(inode) > 0 || adb_controller == NULL)
 653                 return -ENXIO;
 654         state = kmalloc(sizeof(struct adbdev_state), GFP_KERNEL);
 655         if (state == 0)
 656                 return -ENOMEM;
 657         file->private_data = state;
 658         spin_lock_init(&state->lock);
 659         atomic_set(&state->n_pending, 0);
 660         state->completed = NULL;
 661         init_waitqueue_head(&state->wait_queue);
 662         state->inuse = 1;
 663
 664         return 0;
 665 }
 666
 667 static int adb_release(struct inode *inode, struct file *file)
 668 {
 669         struct adbdev_state *state = file->private_data;
 670         unsigned long flags;
 671
 672         lock_kernel();
 673         if (state) {
 674                 file->private_data = NULL;
 675                 spin_lock_irqsave(&state->lock, flags);
 676                 if (atomic_read(&state->n_pending) == 0
 677                     && state->completed == NULL) {
 678                         spin_unlock_irqrestore(&state->lock, flags);
 679                         kfree(state);
 680                 } else {
 681                         state->inuse = 0;
 682                         spin_unlock_irqrestore(&state->lock, flags);
 683                 }
 684         }
 685         unlock_kernel();
 686         return 0;
 687 }
 688
 689 static ssize_t adb_read(struct file *file, char __user *buf,
 690                         size_t count, loff_t *ppos)
 691 {
 692         int ret = 0;
 693         struct adbdev_state *state = file->private_data;
 694         struct adb_request *req;
 695         wait_queue_t wait = __WAITQUEUE_INITIALIZER(wait,current);
 696         unsigned long flags;
 697
 698         if (count < 2)
 699                 return -EINVAL;
 700         if (count > sizeof(req->reply))
 701                 count = sizeof(req->reply);
 702         if (!access_ok(VERIFY_WRITE, buf, count))
 703                 return -EFAULT;
 704
 705         req = NULL;
 706         spin_lock_irqsave(&state->lock, flags);
 707         add_wait_queue(&state->wait_queue, &wait);
 708         current->state = TASK_INTERRUPTIBLE;
 709
 710         for (;;) {
 711                 req = state->completed;
 712                 if (req != NULL)
 713                         state->completed = req->next;
 714                 else if (atomic_read(&state->n_pending) == 0)
 715                         ret = -EIO;
 716                 if (req != NULL || ret != 0)
 717                         break;
 718
 719                 if (file->f_flags & O_NONBLOCK) {
 720                         ret = -EAGAIN;
 721                         break;
 722                 }
 723                 if (signal_pending(current)) {
 724                         ret = -ERESTARTSYS;
 725                         break;
 726                 }
 727                 spin_unlock_irqrestore(&state->lock, flags);
 728                 schedule();
 729                 spin_lock_irqsave(&state->lock, flags);
 730         }
 731
 732         current->state = TASK_RUNNING;
 733         remove_wait_queue(&state->wait_queue, &wait);
 734         spin_unlock_irqrestore(&state->lock, flags);
 735
 736         if (ret)
 737                 return ret;
 738
 739         ret = req->reply_len;
 740         if (ret > count)
 741                 ret = count;
 742         if (ret > 0 && copy_to_user(buf, req->reply, ret))
 743                 ret = -EFAULT;
 744
 745         kfree(req);
 746         return ret;
 747 }
 748
 749 static ssize_t adb_write(struct file *file, const char __user *buf,
 750                          size_t count, loff_t *ppos)
 751 {
 752         int ret/*, i*/;
 753         struct adbdev_state *state = file->private_data;
 754         struct adb_request *req;
 755
 756         if (count < 2 || count > sizeof(req->data))
 757                 return -EINVAL;
 758         if (adb_controller == NULL)
 759                 return -ENXIO;
 760         if (!access_ok(VERIFY_READ, buf, count))
 761                 return -EFAULT;
 762
 763         req = kmalloc(sizeof(struct adb_request),
 764                                              GFP_KERNEL);
 765         if (req == NULL)
 766                 return -ENOMEM;
 767
 768         req->nbytes = count;
 769         req->done = adb_write_done;
 770         req->arg = (void *) state;
 771         req->complete = 0;
 772
 773         ret = -EFAULT;
 774         if (copy_from_user(req->data, buf, count))
 775                 goto out;
 776
 777         atomic_inc(&state->n_pending);
 778
 779         /* If a probe is in progress or we are sleeping, wait for it to complete */
 780         down(&adb_probe_mutex);
 781
 782         /* Queries are special requests sent to the ADB driver itself */
 783         if (req->data[0] == ADB_QUERY) {
 784                 if (count > 1)
 785                         ret = do_adb_query(req);
 786                 else
 787                         ret = -EINVAL;
 788                 up(&adb_probe_mutex);
 789         }
 790         /* Special case for ADB_BUSRESET request, all others are sent to
 791            the controller */
 792         else if ((req->data[0] == ADB_PACKET)&&(count > 1)
 793                 &&(req->data[1] == ADB_BUSRESET)) {
 794                 ret = do_adb_reset_bus();
 795                 up(&adb_probe_mutex);
 796                 atomic_dec(&state->n_pending);
 797                 if (ret == 0)
 798                         ret = count;
 799                 goto out;
 800         } else {
 801                 req->reply_expected = ((req->data[1] & 0xc) == 0xc);
 802                 if (adb_controller && adb_controller->send_request)
 803                         ret = adb_controller->send_request(req, 0);
 804                 else
 805                         ret = -ENXIO;
 806                 up(&adb_probe_mutex);
 807         }
 808
 809         if (ret != 0) {
 810                 atomic_dec(&state->n_pending);
 811                 goto out;
 812         }
 813         return count;
 814
 815 out:
 816         kfree(req);
 817         return ret;
 818 }
 819
 820 static const struct file_operations adb_fops = {
 821         .owner          = THIS_MODULE,
 822         .llseek         = no_llseek,
 823         .read           = adb_read,
 824         .write          = adb_write,
 825         .open           = adb_open,
 826         .release        = adb_release,
 827 };
 828
 829 static struct platform_driver adb_pfdrv = {
 830         .driver = {
 831                 .name = "adb",
 832         },
 833 #ifdef CONFIG_PM
 834         .suspend = adb_suspend,
 835         .resume = adb_resume,
 836 #endif
 837 };
 838
 839 static struct platform_device adb_pfdev = {
 840         .name = "adb",
 841 };
 842
 843 static int __init
 844 adb_dummy_probe(struct platform_device *dev)
 845 {
 846         if (dev == &adb_pfdev)
 847                 return 0;
 848         return -ENODEV;
 849 }
 850
 851 static void __init
 852 adbdev_init(void)
 853 {
 854         if (register_chrdev(ADB_MAJOR, "adb", &adb_fops)) {
 855                 printk(KERN_ERR "adb: unable to get major %d\n", ADB_MAJOR);
 856                 return;
 857         }
 858
 859         adb_dev_class = class_create(THIS_MODULE, "adb");
 860         if (IS_ERR(adb_dev_class))
 861                 return;
 862         device_create(adb_dev_class, NULL, MKDEV(ADB_MAJOR, 0), "adb");
 863
 864         platform_device_register(&adb_pfdev);
 865         platform_driver_probe(&adb_pfdrv, adb_dummy_probe);
 866 }