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
  39 #include <asm/uaccess.h>
  40 #include <asm/semaphore.h>
  41 #ifdef CONFIG_PPC
  42 #include <asm/prom.h>
  43 #include <asm/machdep.h>
  44 #endif
  45
  46
  47 EXPORT_SYMBOL(adb_controller);
  48 EXPORT_SYMBOL(adb_client_list);
  49
  50 extern struct adb_driver via_macii_driver;
  51 extern struct adb_driver via_maciisi_driver;
  52 extern struct adb_driver via_cuda_driver;
  53 extern struct adb_driver adb_iop_driver;
  54 extern struct adb_driver via_pmu_driver;
  55 extern struct adb_driver macio_adb_driver;
  56
  57 static struct adb_driver *adb_driver_list[] = {
  58 #ifdef CONFIG_ADB_MACII
  59         &via_macii_driver,
  60 #endif
  61 #ifdef CONFIG_ADB_MACIISI
  62         &via_maciisi_driver,
  63 #endif
  64 #ifdef CONFIG_ADB_CUDA
  65         &via_cuda_driver,
  66 #endif
  67 #ifdef CONFIG_ADB_IOP
  68         &adb_iop_driver,
  69 #endif
  70 #if defined(CONFIG_ADB_PMU) || defined(CONFIG_ADB_PMU68K)
  71         &via_pmu_driver,
  72 #endif
  73 #ifdef CONFIG_ADB_MACIO
  74         &macio_adb_driver,
  75 #endif
  76         NULL
  77 };
  78
  79 static struct class *adb_dev_class;
  80
  81 struct adb_driver *adb_controller;
  82 BLOCKING_NOTIFIER_HEAD(adb_client_list);
  83 static int adb_got_sleep;
  84 static int adb_inited;
  85 static pid_t adb_probe_task_pid;
  86 static DECLARE_MUTEX(adb_probe_mutex);
  87 static struct completion adb_probe_task_comp;
  88 static int sleepy_trackpad;
  89 static int autopoll_devs;
  90 int __adb_probe_sync;
  91
  92 #ifdef CONFIG_PM
  93 static int adb_notify_sleep(struct pmu_sleep_notifier *self, int when);
  94 static struct pmu_sleep_notifier adb_sleep_notifier = {
  95         adb_notify_sleep,
  96         SLEEP_LEVEL_ADB,
  97 };
  98 #endif
  99
 100 static int adb_scan_bus(void);
 101 static int do_adb_reset_bus(void);
 102 static void adbdev_init(void);
 103 static int try_handler_change(int, int);
 104
 105 static struct adb_handler {
 106         void (*handler)(unsigned char *, int, int);
 107         int original_address;
 108         int handler_id;
 109         int busy;
 110 } adb_handler[16];
 111
 112 /*
 113  * The adb_handler_sem mutex protects all accesses to the original_address
 114  * and handler_id fields of adb_handler[i] for all i, and changes to the
 115  * handler field.
 116  * Accesses to the handler field are protected by the adb_handler_lock
 117  * rwlock.  It is held across all calls to any handler, so that by the
 118  * time adb_unregister returns, we know that the old handler isn't being
 119  * called.
 120  */
 121 static DECLARE_MUTEX(adb_handler_sem);
 122 static DEFINE_RWLOCK(adb_handler_lock);
 123
 124 #if 0
 125 static void printADBreply(struct adb_request *req)
 126 {
 127         int i;
 128
 129         printk("adb reply (%d)", req->reply_len);
 130         for(i = 0; i < req->reply_len; i++)
 131                 printk(" %x", req->reply[i]);
 132         printk("\n");
 133
 134 }
 135 #endif
 136
 137
 138 static __inline__ void adb_wait_ms(unsigned int ms)
 139 {
 140         if (current->pid && adb_probe_task_pid &&
 141           adb_probe_task_pid == current->pid)
 142                 msleep(ms);
 143         else
 144                 mdelay(ms);
 145 }
 146
 147 static int adb_scan_bus(void)
 148 {
 149         int i, highFree=0, noMovement;
 150         int devmask = 0;
 151         struct adb_request req;
 152
 153         /* assumes adb_handler[] is all zeroes at this point */
 154         for (i = 1; i < 16; i++) {
 155                 /* see if there is anything at address i */
 156                 adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 157                             (i << 4) | 0xf);
 158                 if (req.reply_len > 1)
 159                         /* one or more devices at this address */
 160                         adb_handler[i].original_address = i;
 161                 else if (i > highFree)
 162                         highFree = i;
 163         }
 164
 165         /* Note we reset noMovement to 0 each time we move a device */
 166         for (noMovement = 1; noMovement < 2 && highFree > 0; noMovement++) {
 167                 for (i = 1; i < 16; i++) {
 168                         if (adb_handler[i].original_address == 0)
 169                                 continue;
 170                         /*
 171                          * Send a "talk register 3" command to address i
 172                          * to provoke a collision if there is more than
 173                          * one device at this address.
 174                          */
 175                         adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 176                                     (i << 4) | 0xf);
 177                         /*
 178                          * Move the device(s) which didn't detect a
 179                          * collision to address `highFree'.  Hopefully
 180                          * this only moves one device.
 181                          */
 182                         adb_request(&req, NULL, ADBREQ_SYNC, 3,
 183                                     (i<< 4) | 0xb, (highFree | 0x60), 0xfe);
 184                         /*
 185                          * See if anybody actually moved. This is suggested
 186                          * by HW TechNote 01:
 187                          *
 188                          * http://developer.apple.com/technotes/hw/hw_01.html
 189                          */
 190                         adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 191                                     (highFree << 4) | 0xf);
 192                         if (req.reply_len <= 1) continue;
 193                         /*
 194                          * Test whether there are any device(s) left
 195                          * at address i.
 196                          */
 197                         adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 198                                     (i << 4) | 0xf);
 199                         if (req.reply_len > 1) {
 200                                 /*
 201                                  * There are still one or more devices
 202                                  * left at address i.  Register the one(s)
 203                                  * we moved to `highFree', and find a new
 204                                  * value for highFree.
 205                                  */
 206                                 adb_handler[highFree].original_address =
 207                                         adb_handler[i].original_address;
 208                                 while (highFree > 0 &&
 209                                        adb_handler[highFree].original_address)
 210                                         highFree--;
 211                                 if (highFree <= 0)
 212                                         break;
 213
 214                                 noMovement = 0;
 215                         }
 216                         else {
 217                                 /*
 218                                  * No devices left at address i; move the
 219                                  * one(s) we moved to `highFree' back to i.
 220                                  */
 221                                 adb_request(&req, NULL, ADBREQ_SYNC, 3,
 222                                             (highFree << 4) | 0xb,
 223                                             (i | 0x60), 0xfe);
 224                         }
 225                 }
 226         }
 227
 228         /* Now fill in the handler_id field of the adb_handler entries. */
 229         printk(KERN_DEBUG "adb devices:");
 230         for (i = 1; i < 16; i++) {
 231                 if (adb_handler[i].original_address == 0)
 232                         continue;
 233                 adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 234                             (i << 4) | 0xf);
 235                 adb_handler[i].handler_id = req.reply[2];
 236                 printk(" [%d]: %d %x", i, adb_handler[i].original_address,
 237                        adb_handler[i].handler_id);
 238                 devmask |= 1 << i;
 239         }
 240         printk("\n");
 241         return devmask;
 242 }
 243
 244 /*
 245  * This kernel task handles ADB probing. It dies once probing is
 246  * completed.
 247  */
 248 static int
 249 adb_probe_task(void *x)
 250 {
 251         sigset_t blocked;
 252
 253         strcpy(current->comm, "kadbprobe");
 254
 255         sigfillset(&blocked);
 256         sigprocmask(SIG_BLOCK, &blocked, NULL);
 257         flush_signals(current);
 258
 259         printk(KERN_INFO "adb: starting probe task...\n");
 260         do_adb_reset_bus();
 261         printk(KERN_INFO "adb: finished probe task...\n");
 262
 263         adb_probe_task_pid = 0;
 264         up(&adb_probe_mutex);
 265
 266         return 0;
 267 }
 268
 269 static void
 270 __adb_probe_task(struct work_struct *bullshit)
 271 {
 272         adb_probe_task_pid = kernel_thread(adb_probe_task, NULL, SIGCHLD | CLONE_KERNEL);
 273 }
 274
 275 static DECLARE_WORK(adb_reset_work, __adb_probe_task);
 276
 277 int
 278 adb_reset_bus(void)
 279 {
 280         if (__adb_probe_sync) {
 281                 do_adb_reset_bus();
 282                 return 0;
 283         }
 284
 285         down(&adb_probe_mutex);
 286         schedule_work(&adb_reset_work);
 287         return 0;
 288 }
 289
 290 int __init adb_init(void)
 291 {
 292         struct adb_driver *driver;
 293         int i;
 294
 295 #ifdef CONFIG_PPC32
 296         if (!machine_is(chrp) && !machine_is(powermac))
 297                 return 0;
 298 #endif
 299 #ifdef CONFIG_MAC
 300         if (!MACH_IS_MAC)
 301                 return 0;
 302 #endif
 303
 304         /* xmon may do early-init */
 305         if (adb_inited)
 306                 return 0;
 307         adb_inited = 1;
 308
 309         adb_controller = NULL;
 310
 311         i = 0;
 312         while ((driver = adb_driver_list[i++]) != NULL) {
 313                 if (!driver->probe()) {
 314                         adb_controller = driver;
 315                         break;
 316                 }
 317         }
 318         if ((adb_controller == NULL) || adb_controller->init()) {
 319                 printk(KERN_WARNING "Warning: no ADB interface detected\n");
 320                 adb_controller = NULL;
 321         } else {
 322 #ifdef CONFIG_PM
 323                 pmu_register_sleep_notifier(&adb_sleep_notifier);
 324 #endif /* CONFIG_PM */
 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                 init_completion(&adb_probe_task_comp);
 331                 adbdev_init();
 332                 adb_reset_bus();
 333         }
 334         return 0;
 335 }
 336
 337 __initcall(adb_init);
 338
 339 #ifdef CONFIG_PM
 340 /*
 341  * notify clients before sleep and reset bus afterwards
 342  */
 343 int
 344 adb_notify_sleep(struct pmu_sleep_notifier *self, int when)
 345 {
 346         int ret;
 347
 348         switch (when) {
 349         case PBOOK_SLEEP_REQUEST:
 350                 adb_got_sleep = 1;
 351                 /* We need to get a lock on the probe thread */
 352                 down(&adb_probe_mutex);
 353                 /* Stop autopoll */
 354                 if (adb_controller->autopoll)
 355                         adb_controller->autopoll(0);
 356                 ret = blocking_notifier_call_chain(&adb_client_list,
 357                                 ADB_MSG_POWERDOWN, NULL);
 358                 if (ret & NOTIFY_STOP_MASK) {
 359                         up(&adb_probe_mutex);
 360                         return PBOOK_SLEEP_REFUSE;
 361                 }
 362                 break;
 363         case PBOOK_SLEEP_REJECT:
 364                 if (adb_got_sleep) {
 365                         adb_got_sleep = 0;
 366                         up(&adb_probe_mutex);
 367                         adb_reset_bus();
 368                 }
 369                 break;
 370
 371         case PBOOK_SLEEP_NOW:
 372                 break;
 373         case PBOOK_WAKE:
 374                 adb_got_sleep = 0;
 375                 up(&adb_probe_mutex);
 376                 adb_reset_bus();
 377                 break;
 378         }
 379         return PBOOK_SLEEP_OK;
 380 }
 381 #endif /* CONFIG_PM */
 382
 383 static int
 384 do_adb_reset_bus(void)
 385 {
 386         int ret, nret;
 387
 388         if (adb_controller == NULL)
 389                 return -ENXIO;
 390
 391         if (adb_controller->autopoll)
 392                 adb_controller->autopoll(0);
 393
 394         nret = blocking_notifier_call_chain(&adb_client_list,
 395                         ADB_MSG_PRE_RESET, NULL);
 396         if (nret & NOTIFY_STOP_MASK) {
 397                 if (adb_controller->autopoll)
 398                         adb_controller->autopoll(autopoll_devs);
 399                 return -EBUSY;
 400         }
 401
 402         if (sleepy_trackpad) {
 403                 /* Let the trackpad settle down */
 404                 adb_wait_ms(500);
 405         }
 406
 407         down(&adb_handler_sem);
 408         write_lock_irq(&adb_handler_lock);
 409         memset(adb_handler, 0, sizeof(adb_handler));
 410         write_unlock_irq(&adb_handler_lock);
 411
 412         /* That one is still a bit synchronous, oh well... */
 413         if (adb_controller->reset_bus)
 414                 ret = adb_controller->reset_bus();
 415         else
 416                 ret = 0;
 417
 418         if (sleepy_trackpad) {
 419                 /* Let the trackpad settle down */
 420                 adb_wait_ms(1500);
 421         }
 422
 423         if (!ret) {
 424                 autopoll_devs = adb_scan_bus();
 425                 if (adb_controller->autopoll)
 426                         adb_controller->autopoll(autopoll_devs);
 427         }
 428         up(&adb_handler_sem);
 429
 430         nret = blocking_notifier_call_chain(&adb_client_list,
 431                         ADB_MSG_POST_RESET, NULL);
 432         if (nret & NOTIFY_STOP_MASK)
 433                 return -EBUSY;
 434
 435         return ret;
 436 }
 437
 438 void
 439 adb_poll(void)
 440 {
 441         if ((adb_controller == NULL)||(adb_controller->poll == NULL))
 442                 return;
 443         adb_controller->poll();
 444 }
 445
 446 static void
 447 adb_probe_wakeup(struct adb_request *req)
 448 {
 449         complete(&adb_probe_task_comp);
 450 }
 451
 452 /* Static request used during probe */
 453 static struct adb_request adb_sreq;
 454 static unsigned long adb_sreq_lock; // Use semaphore ! */
 455
 456 int
 457 adb_request(struct adb_request *req, void (*done)(struct adb_request *),
 458             int flags, int nbytes, ...)
 459 {
 460         va_list list;
 461         int i, use_sreq;
 462         int rc;
 463
 464         if ((adb_controller == NULL) || (adb_controller->send_request == NULL))
 465                 return -ENXIO;
 466         if (nbytes < 1)
 467                 return -EINVAL;
 468         if (req == NULL && (flags & ADBREQ_NOSEND))
 469                 return -EINVAL;
 470
 471         if (req == NULL) {
 472                 if (test_and_set_bit(0,&adb_sreq_lock)) {
 473                         printk("adb.c: Warning: contention on static request !\n");
 474                         return -EPERM;
 475                 }
 476                 req = &adb_sreq;
 477                 flags |= ADBREQ_SYNC;
 478                 use_sreq = 1;
 479         } else
 480                 use_sreq = 0;
 481         req->nbytes = nbytes+1;
 482         req->done = done;
 483         req->reply_expected = flags & ADBREQ_REPLY;
 484         req->data[0] = ADB_PACKET;
 485         va_start(list, nbytes);
 486         for (i = 0; i < nbytes; ++i)
 487                 req->data[i+1] = va_arg(list, int);
 488         va_end(list);
 489
 490         if (flags & ADBREQ_NOSEND)
 491                 return 0;
 492
 493         /* Synchronous requests send from the probe thread cause it to
 494          * block. Beware that the "done" callback will be overriden !
 495          */
 496         if ((flags & ADBREQ_SYNC) &&
 497             (current->pid && adb_probe_task_pid &&
 498             adb_probe_task_pid == current->pid)) {
 499                 req->done = adb_probe_wakeup;
 500                 rc = adb_controller->send_request(req, 0);
 501                 if (rc || req->complete)
 502                         goto bail;
 503                 wait_for_completion(&adb_probe_task_comp);
 504                 rc = 0;
 505                 goto bail;
 506         }
 507
 508         rc = adb_controller->send_request(req, flags & ADBREQ_SYNC);
 509 bail:
 510         if (use_sreq)
 511                 clear_bit(0, &adb_sreq_lock);
 512
 513         return rc;
 514 }
 515
 516  /* Ultimately this should return the number of devices with
 517     the given default id.
 518     And it does it now ! Note: changed behaviour: This function
 519     will now register if default_id _and_ handler_id both match
 520     but handler_id can be left to 0 to match with default_id only.
 521     When handler_id is set, this function will try to adjust
 522     the handler_id id it doesn't match. */
 523 int
 524 adb_register(int default_id, int handler_id, struct adb_ids *ids,
 525              void (*handler)(unsigned char *, int, int))
 526 {
 527         int i;
 528
 529         down(&adb_handler_sem);
 530         ids->nids = 0;
 531         for (i = 1; i < 16; i++) {
 532                 if ((adb_handler[i].original_address == default_id) &&
 533                     (!handler_id || (handler_id == adb_handler[i].handler_id) ||
 534                     try_handler_change(i, handler_id))) {
 535                         if (adb_handler[i].handler != 0) {
 536                                 printk(KERN_ERR
 537                                        "Two handlers for ADB device %d\n",
 538                                        default_id);
 539                                 continue;
 540                         }
 541                         write_lock_irq(&adb_handler_lock);
 542                         adb_handler[i].handler = handler;
 543                         write_unlock_irq(&adb_handler_lock);
 544                         ids->id[ids->nids++] = i;
 545                 }
 546         }
 547         up(&adb_handler_sem);
 548         return ids->nids;
 549 }
 550
 551 int
 552 adb_unregister(int index)
 553 {
 554         int ret = -ENODEV;
 555
 556         down(&adb_handler_sem);
 557         write_lock_irq(&adb_handler_lock);
 558         if (adb_handler[index].handler) {
 559                 while(adb_handler[index].busy) {
 560                         write_unlock_irq(&adb_handler_lock);
 561                         yield();
 562                         write_lock_irq(&adb_handler_lock);
 563                 }
 564                 ret = 0;
 565                 adb_handler[index].handler = NULL;
 566         }
 567         write_unlock_irq(&adb_handler_lock);
 568         up(&adb_handler_sem);
 569         return ret;
 570 }
 571
 572 void
 573 adb_input(unsigned char *buf, int nb, int autopoll)
 574 {
 575         int i, id;
 576         static int dump_adb_input = 0;
 577         unsigned long flags;
 578
 579         void (*handler)(unsigned char *, int, int);
 580
 581         /* We skip keystrokes and mouse moves when the sleep process
 582          * has been started. We stop autopoll, but this is another security
 583          */
 584         if (adb_got_sleep)
 585                 return;
 586
 587         id = buf[0] >> 4;
 588         if (dump_adb_input) {
 589                 printk(KERN_INFO "adb packet: ");
 590                 for (i = 0; i < nb; ++i)
 591                         printk(" %x", buf[i]);
 592                 printk(", id = %d\n", id);
 593         }
 594         write_lock_irqsave(&adb_handler_lock, flags);
 595         handler = adb_handler[id].handler;
 596         if (handler != NULL)
 597                 adb_handler[id].busy = 1;
 598         write_unlock_irqrestore(&adb_handler_lock, flags);
 599         if (handler != NULL) {
 600                 (*handler)(buf, nb, autopoll);
 601                 wmb();
 602                 adb_handler[id].busy = 0;
 603         }
 604
 605 }
 606
 607 /* Try to change handler to new_id. Will return 1 if successful. */
 608 static int try_handler_change(int address, int new_id)
 609 {
 610         struct adb_request req;
 611
 612         if (adb_handler[address].handler_id == new_id)
 613             return 1;
 614         adb_request(&req, NULL, ADBREQ_SYNC, 3,
 615             ADB_WRITEREG(address, 3), address | 0x20, new_id);
 616         adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
 617             ADB_READREG(address, 3));
 618         if (req.reply_len < 2)
 619             return 0;
 620         if (req.reply[2] != new_id)
 621             return 0;
 622         adb_handler[address].handler_id = req.reply[2];
 623
 624         return 1;
 625 }
 626
 627 int
 628 adb_try_handler_change(int address, int new_id)
 629 {
 630         int ret;
 631
 632         down(&adb_handler_sem);
 633         ret = try_handler_change(address, new_id);
 634         up(&adb_handler_sem);
 635         return ret;
 636 }
 637
 638 int
 639 adb_get_infos(int address, int *original_address, int *handler_id)
 640 {
 641         down(&adb_handler_sem);
 642         *original_address = adb_handler[address].original_address;
 643         *handler_id = adb_handler[address].handler_id;
 644         up(&adb_handler_sem);
 645
 646         return (*original_address != 0);
 647 }
 648
 649
 650 /*
 651  * /dev/adb device driver.
 652  */
 653
 654 #define ADB_MAJOR       56      /* major number for /dev/adb */
 655
 656 struct adbdev_state {
 657         spinlock_t      lock;
 658         atomic_t        n_pending;
 659         struct adb_request *completed;
 660         wait_queue_head_t wait_queue;
 661         int             inuse;
 662 };
 663
 664 static void adb_write_done(struct adb_request *req)
 665 {
 666         struct adbdev_state *state = (struct adbdev_state *) req->arg;
 667         unsigned long flags;
 668
 669         if (!req->complete) {
 670                 req->reply_len = 0;
 671                 req->complete = 1;
 672         }
 673         spin_lock_irqsave(&state->lock, flags);
 674         atomic_dec(&state->n_pending);
 675         if (!state->inuse) {
 676                 kfree(req);
 677                 if (atomic_read(&state->n_pending) == 0) {
 678                         spin_unlock_irqrestore(&state->lock, flags);
 679                         kfree(state);
 680                         return;
 681                 }
 682         } else {
 683                 struct adb_request **ap = &state->completed;
 684                 while (*ap != NULL)
 685                         ap = &(*ap)->next;
 686                 req->next = NULL;
 687                 *ap = req;
 688                 wake_up_interruptible(&state->wait_queue);
 689         }
 690         spin_unlock_irqrestore(&state->lock, flags);
 691 }
 692
 693 static int
 694 do_adb_query(struct adb_request *req)
 695 {
 696         int     ret = -EINVAL;
 697
 698         switch(req->data[1])
 699         {
 700         case ADB_QUERY_GETDEVINFO:
 701                 if (req->nbytes < 3)
 702                         break;
 703                 down(&adb_handler_sem);
 704                 req->reply[0] = adb_handler[req->data[2]].original_address;
 705                 req->reply[1] = adb_handler[req->data[2]].handler_id;
 706                 up(&adb_handler_sem);
 707                 req->complete = 1;
 708                 req->reply_len = 2;
 709                 adb_write_done(req);
 710                 ret = 0;
 711                 break;
 712         }
 713         return ret;
 714 }
 715
 716 static int adb_open(struct inode *inode, struct file *file)
 717 {
 718         struct adbdev_state *state;
 719
 720         if (iminor(inode) > 0 || adb_controller == NULL)
 721                 return -ENXIO;
 722         state = kmalloc(sizeof(struct adbdev_state), GFP_KERNEL);
 723         if (state == 0)
 724                 return -ENOMEM;
 725         file->private_data = state;
 726         spin_lock_init(&state->lock);
 727         atomic_set(&state->n_pending, 0);
 728         state->completed = NULL;
 729         init_waitqueue_head(&state->wait_queue);
 730         state->inuse = 1;
 731
 732         return 0;
 733 }
 734
 735 static int adb_release(struct inode *inode, struct file *file)
 736 {
 737         struct adbdev_state *state = file->private_data;
 738         unsigned long flags;
 739
 740         lock_kernel();
 741         if (state) {
 742                 file->private_data = NULL;
 743                 spin_lock_irqsave(&state->lock, flags);
 744                 if (atomic_read(&state->n_pending) == 0
 745                     && state->completed == NULL) {
 746                         spin_unlock_irqrestore(&state->lock, flags);
 747                         kfree(state);
 748                 } else {
 749                         state->inuse = 0;
 750                         spin_unlock_irqrestore(&state->lock, flags);
 751                 }
 752         }
 753         unlock_kernel();
 754         return 0;
 755 }
 756
 757 static ssize_t adb_read(struct file *file, char __user *buf,
 758                         size_t count, loff_t *ppos)
 759 {
 760         int ret = 0;
 761         struct adbdev_state *state = file->private_data;
 762         struct adb_request *req;
 763         wait_queue_t wait = __WAITQUEUE_INITIALIZER(wait,current);
 764         unsigned long flags;
 765
 766         if (count < 2)
 767                 return -EINVAL;
 768         if (count > sizeof(req->reply))
 769                 count = sizeof(req->reply);
 770         if (!access_ok(VERIFY_WRITE, buf, count))
 771                 return -EFAULT;
 772
 773         req = NULL;
 774         spin_lock_irqsave(&state->lock, flags);
 775         add_wait_queue(&state->wait_queue, &wait);
 776         current->state = TASK_INTERRUPTIBLE;
 777
 778         for (;;) {
 779                 req = state->completed;
 780                 if (req != NULL)
 781                         state->completed = req->next;
 782                 else if (atomic_read(&state->n_pending) == 0)
 783                         ret = -EIO;
 784                 if (req != NULL || ret != 0)
 785                         break;
 786
 787                 if (file->f_flags & O_NONBLOCK) {
 788                         ret = -EAGAIN;
 789                         break;
 790                 }
 791                 if (signal_pending(current)) {
 792                         ret = -ERESTARTSYS;
 793                         break;
 794                 }
 795                 spin_unlock_irqrestore(&state->lock, flags);
 796                 schedule();
 797                 spin_lock_irqsave(&state->lock, flags);
 798         }
 799
 800         current->state = TASK_RUNNING;
 801         remove_wait_queue(&state->wait_queue, &wait);
 802         spin_unlock_irqrestore(&state->lock, flags);
 803
 804         if (ret)
 805                 return ret;
 806
 807         ret = req->reply_len;
 808         if (ret > count)
 809                 ret = count;
 810         if (ret > 0 && copy_to_user(buf, req->reply, ret))
 811                 ret = -EFAULT;
 812
 813         kfree(req);
 814         return ret;
 815 }
 816
 817 static ssize_t adb_write(struct file *file, const char __user *buf,
 818                          size_t count, loff_t *ppos)
 819 {
 820         int ret/*, i*/;
 821         struct adbdev_state *state = file->private_data;
 822         struct adb_request *req;
 823
 824         if (count < 2 || count > sizeof(req->data))
 825                 return -EINVAL;
 826         if (adb_controller == NULL)
 827                 return -ENXIO;
 828         if (!access_ok(VERIFY_READ, buf, count))
 829                 return -EFAULT;
 830
 831         req = kmalloc(sizeof(struct adb_request),
 832                                              GFP_KERNEL);
 833         if (req == NULL)
 834                 return -ENOMEM;
 835
 836         req->nbytes = count;
 837         req->done = adb_write_done;
 838         req->arg = (void *) state;
 839         req->complete = 0;
 840
 841         ret = -EFAULT;
 842         if (copy_from_user(req->data, buf, count))
 843                 goto out;
 844
 845         atomic_inc(&state->n_pending);
 846
 847         /* If a probe is in progress or we are sleeping, wait for it to complete */
 848         down(&adb_probe_mutex);
 849
 850         /* Queries are special requests sent to the ADB driver itself */
 851         if (req->data[0] == ADB_QUERY) {
 852                 if (count > 1)
 853                         ret = do_adb_query(req);
 854                 else
 855                         ret = -EINVAL;
 856                 up(&adb_probe_mutex);
 857         }
 858         /* Special case for ADB_BUSRESET request, all others are sent to
 859            the controller */
 860         else if ((req->data[0] == ADB_PACKET)&&(count > 1)
 861                 &&(req->data[1] == ADB_BUSRESET)) {
 862                 ret = do_adb_reset_bus();
 863                 up(&adb_probe_mutex);
 864                 atomic_dec(&state->n_pending);
 865                 if (ret == 0)
 866                         ret = count;
 867                 goto out;
 868         } else {
 869                 req->reply_expected = ((req->data[1] & 0xc) == 0xc);
 870                 if (adb_controller && adb_controller->send_request)
 871                         ret = adb_controller->send_request(req, 0);
 872                 else
 873                         ret = -ENXIO;
 874                 up(&adb_probe_mutex);
 875         }
 876
 877         if (ret != 0) {
 878                 atomic_dec(&state->n_pending);
 879                 goto out;
 880         }
 881         return count;
 882
 883 out:
 884         kfree(req);
 885         return ret;
 886 }
 887
 888 static struct file_operations adb_fops = {
 889         .owner          = THIS_MODULE,
 890         .llseek         = no_llseek,
 891         .read           = adb_read,
 892         .write          = adb_write,
 893         .open           = adb_open,
 894         .release        = adb_release,
 895 };
 896
 897 static void
 898 adbdev_init(void)
 899 {
 900         if (register_chrdev(ADB_MAJOR, "adb", &adb_fops)) {
 901                 printk(KERN_ERR "adb: unable to get major %d\n", ADB_MAJOR);
 902                 return;
 903         }
 904
 905         adb_dev_class = class_create(THIS_MODULE, "adb");
 906         if (IS_ERR(adb_dev_class))
 907                 return;
 908         class_device_create(adb_dev_class, NULL, MKDEV(ADB_MAJOR, 0), NULL, "adb");
 909 }