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