drivers/acpi/ec.c

   1 /*
   2  *  acpi_ec.c - ACPI Embedded Controller Driver ($Revision: 38 $)
   3  *
   4  *  Copyright (C) 2004 Luming Yu <luming.yu@intel.com>
   5  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   6  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   7  *
   8  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 2 of the License, or (at
  13  *  your option) any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful, but
  16  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  *  General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License along
  21  *  with this program; if not, write to the Free Software Foundation, Inc.,
  22  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  23  *
  24  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  25  */
  26
  27 #include <linux/kernel.h>
  28 #include <linux/module.h>
  29 #include <linux/init.h>
  30 #include <linux/types.h>
  31 #include <linux/delay.h>
  32 #include <linux/proc_fs.h>
  33 #include <linux/seq_file.h>
  34 #include <linux/interrupt.h>
  35 #include <asm/io.h>
  36 #include <acpi/acpi_bus.h>
  37 #include <acpi/acpi_drivers.h>
  38 #include <acpi/actypes.h>
  39
  40 #define _COMPONENT              ACPI_EC_COMPONENT
  41 ACPI_MODULE_NAME("acpi_ec")
  42 #define ACPI_EC_COMPONENT               0x00100000
  43 #define ACPI_EC_CLASS                   "embedded_controller"
  44 #define ACPI_EC_HID                     "PNP0C09"
  45 #define ACPI_EC_DRIVER_NAME             "ACPI Embedded Controller Driver"
  46 #define ACPI_EC_DEVICE_NAME             "Embedded Controller"
  47 #define ACPI_EC_FILE_INFO               "info"
  48
  49 /* EC status register */
  50 #define ACPI_EC_FLAG_OBF        0x01    /* Output buffer full */
  51 #define ACPI_EC_FLAG_IBF        0x02    /* Input buffer full */
  52 #define ACPI_EC_FLAG_BURST      0x10    /* burst mode */
  53 #define ACPI_EC_FLAG_SCI        0x20    /* EC-SCI occurred */
  54
  55 /* EC commands */
  56 #define ACPI_EC_COMMAND_READ    0x80
  57 #define ACPI_EC_COMMAND_WRITE   0x81
  58 #define ACPI_EC_BURST_ENABLE    0x82
  59 #define ACPI_EC_BURST_DISABLE   0x83
  60 #define ACPI_EC_COMMAND_QUERY   0x84
  61
  62 /* EC events */
  63 enum {
  64         ACPI_EC_EVENT_OBF_1 = 1,        /* Output buffer full */
  65         ACPI_EC_EVENT_IBF_0,            /* Input buffer empty */
  66 };
  67
  68 #define ACPI_EC_DELAY           500     /* Wait 500ms max. during EC ops */
  69 #define ACPI_EC_UDELAY_GLK      1000    /* Wait 1ms max. to get global lock */
  70 #define ACPI_EC_UDELAY         100      /* Poll @ 100us increments */
  71 #define ACPI_EC_UDELAY_COUNT   1000     /* Wait 100ms max. during EC ops */
  72
  73 enum {
  74         EC_INTR = 1,    /* Output buffer full */
  75         EC_POLL,        /* Input buffer empty */
  76 };
  77
  78 static int acpi_ec_remove(struct acpi_device *device, int type);
  79 static int acpi_ec_start(struct acpi_device *device);
  80 static int acpi_ec_stop(struct acpi_device *device, int type);
  81 static int acpi_ec_add(struct acpi_device *device);
  82
  83 static struct acpi_driver acpi_ec_driver = {
  84         .name = ACPI_EC_DRIVER_NAME,
  85         .class = ACPI_EC_CLASS,
  86         .ids = ACPI_EC_HID,
  87         .ops = {
  88                 .add = acpi_ec_add,
  89                 .remove = acpi_ec_remove,
  90                 .start = acpi_ec_start,
  91                 .stop = acpi_ec_stop,
  92                 },
  93 };
  94
  95 /* If we find an EC via the ECDT, we need to keep a ptr to its context */
  96 struct acpi_ec {
  97         acpi_handle handle;
  98         unsigned long uid;
  99         unsigned long gpe_bit;
 100         unsigned long command_addr;
 101         unsigned long data_addr;
 102         unsigned long global_lock;
 103         struct semaphore sem;
 104         unsigned int expect_event;
 105         atomic_t leaving_burst; /* 0 : No, 1 : Yes, 2: abort */
 106         wait_queue_head_t wait;
 107 } *ec_ecdt;
 108
 109 /* External interfaces use first EC only, so remember */
 110 static struct acpi_device *first_ec;
 111 static int acpi_ec_mode = EC_INTR;
 112
 113 /* --------------------------------------------------------------------------
 114                              Transaction Management
 115    -------------------------------------------------------------------------- */
 116
 117 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
 118 {
 119         return inb(ec->command_addr);
 120 }
 121
 122 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
 123 {
 124         return inb(ec->data_addr);
 125 }
 126
 127 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
 128 {
 129         outb(command, ec->command_addr);
 130 }
 131
 132 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
 133 {
 134         outb(data, ec->data_addr);
 135 }
 136
 137 static int acpi_ec_check_status(struct acpi_ec *ec, u8 event)
 138 {
 139         u8 status = acpi_ec_read_status(ec);
 140         switch (event) {
 141         case ACPI_EC_EVENT_OBF_1:
 142                 if (status & ACPI_EC_FLAG_OBF)
 143                         return 1;
 144                 break;
 145         case ACPI_EC_EVENT_IBF_0:
 146                 if (!(status & ACPI_EC_FLAG_IBF))
 147                         return 1;
 148                 break;
 149         default:
 150                 break;
 151         }
 152
 153         return 0;
 154 }
 155
 156 static int acpi_ec_wait(struct acpi_ec *ec, u8 event)
 157 {
 158         int i = (acpi_ec_mode == EC_POLL) ? ACPI_EC_UDELAY_COUNT : 0;
 159         long time_left;
 160
 161         ec->expect_event = event;
 162         if (acpi_ec_check_status(ec, event)) {
 163                 ec->expect_event = 0;
 164                 return 0;
 165         }
 166
 167         do {
 168                 if (acpi_ec_mode == EC_POLL) {
 169                         udelay(ACPI_EC_UDELAY);
 170                 } else {
 171                         time_left = wait_event_timeout(ec->wait,
 172                                     !ec->expect_event,
 173                                     msecs_to_jiffies(ACPI_EC_DELAY));
 174                         if (time_left > 0) {
 175                                 ec->expect_event = 0;
 176                                 return 0;
 177                         }
 178                 }
 179                 if (acpi_ec_check_status(ec, event)) {
 180                         ec->expect_event = 0;
 181                         return 0;
 182                 }
 183         } while (--i > 0);
 184
 185         ec->expect_event = 0;
 186
 187         return -ETIME;
 188 }
 189
 190 #ifdef ACPI_FUTURE_USAGE
 191 /*
 192  * Note: samsung nv5000 doesn't work with ec burst mode.
 193  * http://bugzilla.kernel.org/show_bug.cgi?id=4980
 194  */
 195 int acpi_ec_enter_burst_mode(struct acpi_ec *ec)
 196 {
 197         u8 tmp = 0;
 198         u8 status = 0;
 199
 200
 201         status = acpi_ec_read_status(ec);
 202         if (status != -EINVAL && !(status & ACPI_EC_FLAG_BURST)) {
 203                 status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0);
 204                 if (status)
 205                         goto end;
 206                 acpi_ec_write_cmd(ec, ACPI_EC_BURST_ENABLE);
 207                 status = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF_1);
 208                 tmp = acpi_ec_read_data(ec);
 209                 if (tmp != 0x90) {      /* Burst ACK byte */
 210                         return -EINVAL;
 211                 }
 212         }
 213
 214         atomic_set(&ec->leaving_burst, 0);
 215         return 0;
 216   end:
 217         ACPI_EXCEPTION((AE_INFO, status, "EC wait, burst mode"));
 218         return -1;
 219 }
 220
 221 int acpi_ec_leave_burst_mode(struct acpi_ec *ec)
 222 {
 223         u8 status = 0;
 224
 225
 226         status = acpi_ec_read_status(ec);
 227         if (status != -EINVAL && (status & ACPI_EC_FLAG_BURST)){
 228                 status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0);
 229                 if(status)
 230                         goto end;
 231                 acpi_ec_write_cmd(ec, ACPI_EC_BURST_DISABLE);
 232                 acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0);
 233         }
 234         atomic_set(&ec->leaving_burst, 1);
 235         return 0;
 236   end:
 237         ACPI_EXCEPTION((AE_INFO, status, "EC leave burst mode"));
 238         return -1;
 239 }
 240 #endif /* ACPI_FUTURE_USAGE */
 241
 242 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec, u8 command,
 243                                         const u8 *wdata, unsigned wdata_len,
 244                                         u8 *rdata, unsigned rdata_len)
 245 {
 246         int result;
 247
 248         acpi_ec_write_cmd(ec, command);
 249
 250         for (; wdata_len > 0; wdata_len --) {
 251                 result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0);
 252                 if (result)
 253                         return result;
 254                 acpi_ec_write_data(ec, *(wdata++));
 255         }
 256
 257         if (!rdata_len) {
 258                 result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0);
 259                 if (result)
 260                         return result;
 261         }
 262
 263         for (; rdata_len > 0; rdata_len --) {
 264                 result = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF_1);
 265                 if (result)
 266                         return result;
 267
 268                 *(rdata++) = acpi_ec_read_data(ec);
 269         }
 270
 271         return 0;
 272 }
 273
 274 static int acpi_ec_transaction(struct acpi_ec *ec, u8 command,
 275                                 const u8 *wdata, unsigned wdata_len,
 276                                 u8 *rdata, unsigned rdata_len)
 277 {
 278         int status;
 279         u32 glk;
 280
 281         if (!ec || (wdata_len && !wdata) || (rdata_len && !rdata))
 282                 return -EINVAL;
 283
 284         if (rdata)
 285                 memset(rdata, 0, rdata_len);
 286
 287         if (ec->global_lock) {
 288                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
 289                 if (ACPI_FAILURE(status))
 290                         return -ENODEV;
 291         }
 292         down(&ec->sem);
 293
 294         /* Make sure GPE is enabled before doing transaction */
 295         acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
 296
 297         status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0);
 298         if (status) {
 299                 printk(KERN_DEBUG PREFIX "read EC, IB not empty\n");
 300                 goto end;
 301         }
 302
 303         status = acpi_ec_transaction_unlocked(ec, command,
 304                                               wdata, wdata_len,
 305                                               rdata, rdata_len);
 306
 307 end:
 308         up(&ec->sem);
 309
 310         if (ec->global_lock)
 311                 acpi_release_global_lock(glk);
 312
 313         return status;
 314 }
 315
 316 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
 317 {
 318         int result;
 319         u8 d;
 320
 321         result = acpi_ec_transaction(ec, ACPI_EC_COMMAND_READ,
 322                                      &address, 1, &d, 1);
 323         *data = d;
 324         return result;
 325 }
 326
 327 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
 328 {
 329         u8 wdata[2] = { address, data };
 330         return acpi_ec_transaction(ec, ACPI_EC_COMMAND_WRITE,
 331                                    wdata, 2, NULL, 0);
 332 }
 333
 334 /*
 335  * Externally callable EC access functions. For now, assume 1 EC only
 336  */
 337 int ec_read(u8 addr, u8 *val)
 338 {
 339         struct acpi_ec *ec;
 340         int err;
 341         u8 temp_data;
 342
 343         if (!first_ec)
 344                 return -ENODEV;
 345
 346         ec = acpi_driver_data(first_ec);
 347
 348         err = acpi_ec_read(ec, addr, &temp_data);
 349
 350         if (!err) {
 351                 *val = temp_data;
 352                 return 0;
 353         } else
 354                 return err;
 355 }
 356
 357 EXPORT_SYMBOL(ec_read);
 358
 359 int ec_write(u8 addr, u8 val)
 360 {
 361         struct acpi_ec *ec;
 362         int err;
 363
 364         if (!first_ec)
 365                 return -ENODEV;
 366
 367         ec = acpi_driver_data(first_ec);
 368
 369         err = acpi_ec_write(ec, addr, val);
 370
 371         return err;
 372 }
 373
 374 EXPORT_SYMBOL(ec_write);
 375
 376 extern int ec_transaction(u8 command,
 377                           const u8 *wdata, unsigned wdata_len,
 378                           u8 *rdata, unsigned rdata_len)
 379 {
 380         struct acpi_ec *ec;
 381
 382         if (!first_ec)
 383                 return -ENODEV;
 384
 385         ec = acpi_driver_data(first_ec);
 386
 387         return acpi_ec_transaction(ec, command, wdata,
 388                                    wdata_len, rdata, rdata_len);
 389 }
 390
 391 EXPORT_SYMBOL(ec_transaction);
 392
 393 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
 394 {
 395         int result;
 396         u8 d;
 397
 398         if (!ec || !data)
 399                 return -EINVAL;
 400
 401         /*
 402          * Query the EC to find out which _Qxx method we need to evaluate.
 403          * Note that successful completion of the query causes the ACPI_EC_SCI
 404          * bit to be cleared (and thus clearing the interrupt source).
 405          */
 406
 407         result = acpi_ec_transaction(ec, ACPI_EC_COMMAND_QUERY, NULL, 0, &d, 1);
 408         if (result)
 409                 return result;
 410
 411         if (!d)
 412                 return -ENODATA;
 413
 414         *data = d;
 415         return 0;
 416 }
 417
 418 /* --------------------------------------------------------------------------
 419                                 Event Management
 420    -------------------------------------------------------------------------- */
 421
 422 struct acpi_ec_query_data {
 423         acpi_handle handle;
 424         u8 data;
 425 };
 426
 427 static void acpi_ec_gpe_query(void *ec_cxt)
 428 {
 429         struct acpi_ec *ec = (struct acpi_ec *)ec_cxt;
 430         u8 value = 0;
 431         static char object_name[8];
 432
 433         if (!ec)
 434                 goto end;
 435
 436         value = acpi_ec_read_status(ec);
 437
 438         if (!(value & ACPI_EC_FLAG_SCI))
 439                 goto end;
 440
 441         if (acpi_ec_query(ec, &value))
 442                 goto end;
 443
 444         snprintf(object_name, 8, "_Q%2.2X", value);
 445
 446         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Evaluating %s", object_name));
 447
 448         acpi_evaluate_object(ec->handle, object_name, NULL, NULL);
 449
 450       end:
 451         acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
 452 }
 453
 454 static u32 acpi_ec_gpe_handler(void *data)
 455 {
 456         acpi_status status = AE_OK;
 457         u8 value;
 458         struct acpi_ec *ec = (struct acpi_ec *)data;
 459
 460         acpi_clear_gpe(NULL, ec->gpe_bit, ACPI_ISR);
 461
 462         if (acpi_ec_mode == EC_INTR) {
 463                 if (acpi_ec_check_status(ec, ec->expect_event)) {
 464                         ec->expect_event = 0;
 465                         wake_up(&ec->wait);
 466                 }
 467         }
 468
 469         value = acpi_ec_read_status(ec);
 470         if (value & ACPI_EC_FLAG_SCI) {
 471                 status = acpi_os_execute(OSL_EC_BURST_HANDLER, acpi_ec_gpe_query, ec);
 472                 return status == AE_OK ?
 473                     ACPI_INTERRUPT_HANDLED : ACPI_INTERRUPT_NOT_HANDLED;
 474         }
 475         acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_ISR);
 476         return status == AE_OK ?
 477             ACPI_INTERRUPT_HANDLED : ACPI_INTERRUPT_NOT_HANDLED;
 478 }
 479
 480 /* --------------------------------------------------------------------------
 481                              Address Space Management
 482    -------------------------------------------------------------------------- */
 483
 484 static acpi_status
 485 acpi_ec_space_setup(acpi_handle region_handle,
 486                     u32 function, void *handler_context, void **return_context)
 487 {
 488         /*
 489          * The EC object is in the handler context and is needed
 490          * when calling the acpi_ec_space_handler.
 491          */
 492         *return_context = (function != ACPI_REGION_DEACTIVATE) ?
 493             handler_context : NULL;
 494
 495         return AE_OK;
 496 }
 497
 498 static acpi_status
 499 acpi_ec_space_handler(u32 function,
 500                       acpi_physical_address address,
 501                       u32 bit_width,
 502                       acpi_integer * value,
 503                       void *handler_context, void *region_context)
 504 {
 505         int result = 0;
 506         struct acpi_ec *ec = NULL;
 507         u64 temp = *value;
 508         acpi_integer f_v = 0;
 509         int i = 0;
 510
 511
 512         if ((address > 0xFF) || !value || !handler_context)
 513                 return AE_BAD_PARAMETER;
 514
 515         if (bit_width != 8 && acpi_strict) {
 516                 return AE_BAD_PARAMETER;
 517         }
 518
 519         ec = (struct acpi_ec *)handler_context;
 520
 521       next_byte:
 522         switch (function) {
 523         case ACPI_READ:
 524                 temp = 0;
 525                 result = acpi_ec_read(ec, (u8) address, (u8 *) &temp);
 526                 break;
 527         case ACPI_WRITE:
 528                 result = acpi_ec_write(ec, (u8) address, (u8) temp);
 529                 break;
 530         default:
 531                 result = -EINVAL;
 532                 goto out;
 533                 break;
 534         }
 535
 536         bit_width -= 8;
 537         if (bit_width) {
 538                 if (function == ACPI_READ)
 539                         f_v |= temp << 8 * i;
 540                 if (function == ACPI_WRITE)
 541                         temp >>= 8;
 542                 i++;
 543                 address++;
 544                 goto next_byte;
 545         }
 546
 547         if (function == ACPI_READ) {
 548                 f_v |= temp << 8 * i;
 549                 *value = f_v;
 550         }
 551
 552       out:
 553         switch (result) {
 554         case -EINVAL:
 555                 return AE_BAD_PARAMETER;
 556                 break;
 557         case -ENODEV:
 558                 return AE_NOT_FOUND;
 559                 break;
 560         case -ETIME:
 561                 return AE_TIME;
 562                 break;
 563         default:
 564                 return AE_OK;
 565         }
 566 }
 567
 568 /* --------------------------------------------------------------------------
 569                               FS Interface (/proc)
 570    -------------------------------------------------------------------------- */
 571
 572 static struct proc_dir_entry *acpi_ec_dir;
 573
 574 static int acpi_ec_read_info(struct seq_file *seq, void *offset)
 575 {
 576         struct acpi_ec *ec = (struct acpi_ec *)seq->private;
 577
 578
 579         if (!ec)
 580                 goto end;
 581
 582         seq_printf(seq, "gpe bit:                 0x%02x\n",
 583                    (u32) ec->gpe_bit);
 584         seq_printf(seq, "ports:                   0x%02x, 0x%02x\n",
 585                    (u32) ec->command_addr,
 586                    (u32) ec->data_addr);
 587         seq_printf(seq, "use global lock:         %s\n",
 588                    ec->global_lock ? "yes" : "no");
 589         acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
 590
 591       end:
 592         return 0;
 593 }
 594
 595 static int acpi_ec_info_open_fs(struct inode *inode, struct file *file)
 596 {
 597         return single_open(file, acpi_ec_read_info, PDE(inode)->data);
 598 }
 599
 600 static struct file_operations acpi_ec_info_ops = {
 601         .open = acpi_ec_info_open_fs,
 602         .read = seq_read,
 603         .llseek = seq_lseek,
 604         .release = single_release,
 605         .owner = THIS_MODULE,
 606 };
 607
 608 static int acpi_ec_add_fs(struct acpi_device *device)
 609 {
 610         struct proc_dir_entry *entry = NULL;
 611
 612
 613         if (!acpi_device_dir(device)) {
 614                 acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device),
 615                                                      acpi_ec_dir);
 616                 if (!acpi_device_dir(device))
 617                         return -ENODEV;
 618         }
 619
 620         entry = create_proc_entry(ACPI_EC_FILE_INFO, S_IRUGO,
 621                                   acpi_device_dir(device));
 622         if (!entry)
 623                 return -ENODEV;
 624         else {
 625                 entry->proc_fops = &acpi_ec_info_ops;
 626                 entry->data = acpi_driver_data(device);
 627                 entry->owner = THIS_MODULE;
 628         }
 629
 630         return 0;
 631 }
 632
 633 static int acpi_ec_remove_fs(struct acpi_device *device)
 634 {
 635
 636         if (acpi_device_dir(device)) {
 637                 remove_proc_entry(ACPI_EC_FILE_INFO, acpi_device_dir(device));
 638                 remove_proc_entry(acpi_device_bid(device), acpi_ec_dir);
 639                 acpi_device_dir(device) = NULL;
 640         }
 641
 642         return 0;
 643 }
 644
 645 /* --------------------------------------------------------------------------
 646                                Driver Interface
 647    -------------------------------------------------------------------------- */
 648
 649 static int acpi_ec_add(struct acpi_device *device)
 650 {
 651         int result = 0;
 652         acpi_status status = AE_OK;
 653         struct acpi_ec *ec = NULL;
 654
 655
 656         if (!device)
 657                 return -EINVAL;
 658
 659         ec = kmalloc(sizeof(struct acpi_ec), GFP_KERNEL);
 660         if (!ec)
 661                 return -ENOMEM;
 662         memset(ec, 0, sizeof(struct acpi_ec));
 663
 664         ec->handle = device->handle;
 665         ec->uid = -1;
 666         init_MUTEX(&ec->sem);
 667         if (acpi_ec_mode == EC_INTR) {
 668                 atomic_set(&ec->leaving_burst, 1);
 669                 init_waitqueue_head(&ec->wait);
 670         }
 671         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
 672         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
 673         acpi_driver_data(device) = ec;
 674
 675         /* Use the global lock for all EC transactions? */
 676         acpi_evaluate_integer(ec->handle, "_GLK", NULL,
 677                               &ec->global_lock);
 678
 679         /* XXX we don't test uids, because on some boxes ecdt uid = 0, see:
 680            http://bugzilla.kernel.org/show_bug.cgi?id=6111 */
 681         if (ec_ecdt) {
 682                 acpi_remove_address_space_handler(ACPI_ROOT_OBJECT,
 683                                                   ACPI_ADR_SPACE_EC,
 684                                                   &acpi_ec_space_handler);
 685
 686                 acpi_remove_gpe_handler(NULL, ec_ecdt->gpe_bit,
 687                                         &acpi_ec_gpe_handler);
 688
 689                 kfree(ec_ecdt);
 690         }
 691
 692         /* Get GPE bit assignment (EC events). */
 693         /* TODO: Add support for _GPE returning a package */
 694         status =
 695             acpi_evaluate_integer(ec->handle, "_GPE", NULL,
 696                                   &ec->gpe_bit);
 697         if (ACPI_FAILURE(status)) {
 698                 ACPI_EXCEPTION((AE_INFO, status, "Obtaining GPE bit assignment"));
 699                 result = -ENODEV;
 700                 goto end;
 701         }
 702
 703         result = acpi_ec_add_fs(device);
 704         if (result)
 705                 goto end;
 706
 707         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "%s [%s] (gpe %d) interrupt mode.",
 708                acpi_device_name(device), acpi_device_bid(device),
 709                (u32) ec->gpe_bit));
 710
 711         if (!first_ec)
 712                 first_ec = device;
 713
 714   end:
 715         if (result)
 716                 kfree(ec);
 717
 718         return result;
 719 }
 720
 721 static int acpi_ec_remove(struct acpi_device *device, int type)
 722 {
 723         struct acpi_ec *ec = NULL;
 724
 725
 726         if (!device)
 727                 return -EINVAL;
 728
 729         ec = acpi_driver_data(device);
 730
 731         acpi_ec_remove_fs(device);
 732
 733         kfree(ec);
 734
 735         return 0;
 736 }
 737
 738 static acpi_status
 739 acpi_ec_io_ports(struct acpi_resource *resource, void *context)
 740 {
 741         struct acpi_ec *ec = (struct acpi_ec *)context;
 742
 743         if (resource->type != ACPI_RESOURCE_TYPE_IO) {
 744                 return AE_OK;
 745         }
 746
 747         /*
 748          * The first address region returned is the data port, and
 749          * the second address region returned is the status/command
 750          * port.
 751          */
 752         if (ec->data_addr == 0) {
 753                 ec->data_addr = resource->data.io.minimum;
 754         } else if (ec->command_addr == 0) {
 755                 ec->command_addr = resource->data.io.minimum;
 756         } else {
 757                 return AE_CTRL_TERMINATE;
 758         }
 759
 760         return AE_OK;
 761 }
 762
 763 static int acpi_ec_start(struct acpi_device *device)
 764 {
 765         acpi_status status = AE_OK;
 766         struct acpi_ec *ec = NULL;
 767
 768
 769         if (!device)
 770                 return -EINVAL;
 771
 772         ec = acpi_driver_data(device);
 773
 774         if (!ec)
 775                 return -EINVAL;
 776
 777         /*
 778          * Get I/O port addresses. Convert to GAS format.
 779          */
 780         status = acpi_walk_resources(ec->handle, METHOD_NAME__CRS,
 781                                      acpi_ec_io_ports, ec);
 782         if (ACPI_FAILURE(status) || ec->command_addr == 0) {
 783                 ACPI_EXCEPTION((AE_INFO, status,
 784                                 "Error getting I/O port addresses"));
 785                 return -ENODEV;
 786         }
 787
 788         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "gpe=0x%02lx, ports=0x%2lx,0x%2lx",
 789                           ec->gpe_bit, ec->command_addr, ec->data_addr));
 790
 791         /*
 792          * Install GPE handler
 793          */
 794         status = acpi_install_gpe_handler(NULL, ec->gpe_bit,
 795                                           ACPI_GPE_EDGE_TRIGGERED,
 796                                           &acpi_ec_gpe_handler, ec);
 797         if (ACPI_FAILURE(status)) {
 798                 return -ENODEV;
 799         }
 800         acpi_set_gpe_type(NULL, ec->gpe_bit, ACPI_GPE_TYPE_RUNTIME);
 801         acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
 802
 803         status = acpi_install_address_space_handler(ec->handle,
 804                                                     ACPI_ADR_SPACE_EC,
 805                                                     &acpi_ec_space_handler,
 806                                                     &acpi_ec_space_setup, ec);
 807         if (ACPI_FAILURE(status)) {
 808                 acpi_remove_gpe_handler(NULL, ec->gpe_bit,
 809                                         &acpi_ec_gpe_handler);
 810                 return -ENODEV;
 811         }
 812
 813         return AE_OK;
 814 }
 815
 816 static int acpi_ec_stop(struct acpi_device *device, int type)
 817 {
 818         acpi_status status = AE_OK;
 819         struct acpi_ec *ec = NULL;
 820
 821
 822         if (!device)
 823                 return -EINVAL;
 824
 825         ec = acpi_driver_data(device);
 826
 827         status = acpi_remove_address_space_handler(ec->handle,
 828                                                    ACPI_ADR_SPACE_EC,
 829                                                    &acpi_ec_space_handler);
 830         if (ACPI_FAILURE(status))
 831                 return -ENODEV;
 832
 833         status =
 834             acpi_remove_gpe_handler(NULL, ec->gpe_bit,
 835                                     &acpi_ec_gpe_handler);
 836         if (ACPI_FAILURE(status))
 837                 return -ENODEV;
 838
 839         return 0;
 840 }
 841
 842 static acpi_status __init
 843 acpi_fake_ecdt_callback(acpi_handle handle,
 844                         u32 Level, void *context, void **retval)
 845 {
 846         acpi_status status;
 847
 848         init_MUTEX(&ec_ecdt->sem);
 849         if (acpi_ec_mode == EC_INTR) {
 850                 init_waitqueue_head(&ec_ecdt->wait);
 851         }
 852         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
 853                                      acpi_ec_io_ports, ec_ecdt);
 854         if (ACPI_FAILURE(status))
 855                 return status;
 856
 857         ec_ecdt->uid = -1;
 858         acpi_evaluate_integer(handle, "_UID", NULL, &ec_ecdt->uid);
 859
 860         status =
 861             acpi_evaluate_integer(handle, "_GPE", NULL,
 862                                   &ec_ecdt->gpe_bit);
 863         if (ACPI_FAILURE(status))
 864                 return status;
 865         ec_ecdt->global_lock = TRUE;
 866         ec_ecdt->handle = handle;
 867
 868         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "GPE=0x%02lx, ports=0x%2lx, 0x%2lx",
 869                ec_ecdt->gpe_bit, ec_ecdt->command_addr, ec_ecdt->data_addr));
 870
 871         return AE_CTRL_TERMINATE;
 872 }
 873
 874 /*
 875  * Some BIOS (such as some from Gateway laptops) access EC region very early
 876  * such as in BAT0._INI or EC._INI before an EC device is found and
 877  * do not provide an ECDT. According to ACPI spec, ECDT isn't mandatorily
 878  * required, but if EC regison is accessed early, it is required.
 879  * The routine tries to workaround the BIOS bug by pre-scan EC device
 880  * It assumes that _CRS, _HID, _GPE, _UID methods of EC don't touch any
 881  * op region (since _REG isn't invoked yet). The assumption is true for
 882  * all systems found.
 883  */
 884 static int __init acpi_ec_fake_ecdt(void)
 885 {
 886         acpi_status status;
 887         int ret = 0;
 888
 889         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Try to make an fake ECDT"));
 890
 891         ec_ecdt = kmalloc(sizeof(struct acpi_ec), GFP_KERNEL);
 892         if (!ec_ecdt) {
 893                 ret = -ENOMEM;
 894                 goto error;
 895         }
 896         memset(ec_ecdt, 0, sizeof(struct acpi_ec));
 897
 898         status = acpi_get_devices(ACPI_EC_HID,
 899                                   acpi_fake_ecdt_callback, NULL, NULL);
 900         if (ACPI_FAILURE(status)) {
 901                 kfree(ec_ecdt);
 902                 ec_ecdt = NULL;
 903                 ret = -ENODEV;
 904                 ACPI_EXCEPTION((AE_INFO, status, "Can't make an fake ECDT"));
 905                 goto error;
 906         }
 907         return 0;
 908   error:
 909         return ret;
 910 }
 911
 912 static int __init acpi_ec_get_real_ecdt(void)
 913 {
 914         acpi_status status;
 915         struct acpi_table_ecdt *ecdt_ptr;
 916
 917         status = acpi_get_firmware_table("ECDT", 1, ACPI_LOGICAL_ADDRESSING,
 918                                          (struct acpi_table_header **)
 919                                          &ecdt_ptr);
 920         if (ACPI_FAILURE(status))
 921                 return -ENODEV;
 922
 923         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found ECDT"));
 924
 925         /*
 926          * Generate a temporary ec context to use until the namespace is scanned
 927          */
 928         ec_ecdt = kmalloc(sizeof(struct acpi_ec), GFP_KERNEL);
 929         if (!ec_ecdt)
 930                 return -ENOMEM;
 931         memset(ec_ecdt, 0, sizeof(struct acpi_ec));
 932
 933         init_MUTEX(&ec_ecdt->sem);
 934         if (acpi_ec_mode == EC_INTR) {
 935                 init_waitqueue_head(&ec_ecdt->wait);
 936         }
 937         ec_ecdt->command_addr = ecdt_ptr->ec_control.address;
 938         ec_ecdt->data_addr = ecdt_ptr->ec_data.address;
 939         ec_ecdt->gpe_bit = ecdt_ptr->gpe_bit;
 940         /* use the GL just to be safe */
 941         ec_ecdt->global_lock = TRUE;
 942         ec_ecdt->uid = ecdt_ptr->uid;
 943
 944         status =
 945             acpi_get_handle(NULL, ecdt_ptr->ec_id, &ec_ecdt->handle);
 946         if (ACPI_FAILURE(status)) {
 947                 goto error;
 948         }
 949
 950         return 0;
 951   error:
 952         ACPI_EXCEPTION((AE_INFO, status, "Could not use ECDT"));
 953         kfree(ec_ecdt);
 954         ec_ecdt = NULL;
 955
 956         return -ENODEV;
 957 }
 958
 959 static int __initdata acpi_fake_ecdt_enabled;
 960 int __init acpi_ec_ecdt_probe(void)
 961 {
 962         acpi_status status;
 963         int ret;
 964
 965         ret = acpi_ec_get_real_ecdt();
 966         /* Try to make a fake ECDT */
 967         if (ret && acpi_fake_ecdt_enabled) {
 968                 ret = acpi_ec_fake_ecdt();
 969         }
 970
 971         if (ret)
 972                 return 0;
 973
 974         /*
 975          * Install GPE handler
 976          */
 977         status = acpi_install_gpe_handler(NULL, ec_ecdt->gpe_bit,
 978                                           ACPI_GPE_EDGE_TRIGGERED,
 979                                           &acpi_ec_gpe_handler, ec_ecdt);
 980         if (ACPI_FAILURE(status)) {
 981                 goto error;
 982         }
 983         acpi_set_gpe_type(NULL, ec_ecdt->gpe_bit, ACPI_GPE_TYPE_RUNTIME);
 984         acpi_enable_gpe(NULL, ec_ecdt->gpe_bit, ACPI_NOT_ISR);
 985
 986         status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT,
 987                                                     ACPI_ADR_SPACE_EC,
 988                                                     &acpi_ec_space_handler,
 989                                                     &acpi_ec_space_setup,
 990                                                     ec_ecdt);
 991         if (ACPI_FAILURE(status)) {
 992                 acpi_remove_gpe_handler(NULL, ec_ecdt->gpe_bit,
 993                                         &acpi_ec_gpe_handler);
 994                 goto error;
 995         }
 996
 997         return 0;
 998
 999       error:
1000         ACPI_EXCEPTION((AE_INFO, status, "Could not use ECDT"));
1001         kfree(ec_ecdt);
1002         ec_ecdt = NULL;
1003
1004         return -ENODEV;
1005 }
1006
1007 static int __init acpi_ec_init(void)
1008 {
1009         int result = 0;
1010
1011
1012         if (acpi_disabled)
1013                 return 0;
1014
1015         acpi_ec_dir = proc_mkdir(ACPI_EC_CLASS, acpi_root_dir);
1016         if (!acpi_ec_dir)
1017                 return -ENODEV;
1018
1019         /* Now register the driver for the EC */
1020         result = acpi_bus_register_driver(&acpi_ec_driver);
1021         if (result < 0) {
1022                 remove_proc_entry(ACPI_EC_CLASS, acpi_root_dir);
1023                 return -ENODEV;
1024         }
1025
1026         return result;
1027 }
1028
1029 subsys_initcall(acpi_ec_init);
1030
1031 /* EC driver currently not unloadable */
1032 #if 0
1033 static void __exit acpi_ec_exit(void)
1034 {
1035
1036         acpi_bus_unregister_driver(&acpi_ec_driver);
1037
1038         remove_proc_entry(ACPI_EC_CLASS, acpi_root_dir);
1039
1040         return;
1041 }
1042 #endif                          /* 0 */
1043
1044 static int __init acpi_fake_ecdt_setup(char *str)
1045 {
1046         acpi_fake_ecdt_enabled = 1;
1047         return 1;
1048 }
1049
1050 __setup("acpi_fake_ecdt", acpi_fake_ecdt_setup);
1051 static int __init acpi_ec_set_intr_mode(char *str)
1052 {
1053         int intr;
1054
1055         if (!get_option(&str, &intr))
1056                 return 0;
1057
1058         if (intr) {
1059                 acpi_ec_mode = EC_INTR;
1060         } else {
1061                 acpi_ec_mode = EC_POLL;
1062         }
1063         acpi_ec_driver.ops.add = acpi_ec_add;
1064         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "EC %s mode.\n", intr ? "interrupt" : "polling"));
1065
1066         return 1;
1067 }
1068
1069 __setup("ec_intr=", acpi_ec_set_intr_mode);