drivers/acpi/ec.c

   1 /*
   2  *  ec.c - ACPI Embedded Controller Driver (v2.2)
   3  *
   4  *  Copyright (C) 2001-2014 Intel Corporation
   5  *    Author: 2014       Lv Zheng <lv.zheng@intel.com>
   6  *            2006, 2007 Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
   7  *            2006       Denis Sadykov <denis.m.sadykov@intel.com>
   8  *            2004       Luming Yu <luming.yu@intel.com>
   9  *            2001, 2002 Andy Grover <andrew.grover@intel.com>
  10  *            2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
  11  *  Copyright (C) 2008      Alexey Starikovskiy <astarikovskiy@suse.de>
  12  *
  13  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  14  *
  15  *  This program is free software; you can redistribute it and/or modify
  16  *  it under the terms of the GNU General Public License as published by
  17  *  the Free Software Foundation; either version 2 of the License, or (at
  18  *  your option) any later version.
  19  *
  20  *  This program is distributed in the hope that it will be useful, but
  21  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  22  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  23  *  General Public License for more details.
  24  *
  25  *  You should have received a copy of the GNU General Public License along
  26  *  with this program; if not, write to the Free Software Foundation, Inc.,
  27  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  28  *
  29  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  30  */
  31
  32 /* Uncomment next line to get verbose printout */
  33 /* #define DEBUG */
  34 #define pr_fmt(fmt) "ACPI : EC: " fmt
  35
  36 #include <linux/kernel.h>
  37 #include <linux/module.h>
  38 #include <linux/init.h>
  39 #include <linux/types.h>
  40 #include <linux/delay.h>
  41 #include <linux/interrupt.h>
  42 #include <linux/list.h>
  43 #include <linux/spinlock.h>
  44 #include <linux/slab.h>
  45 #include <linux/acpi.h>
  46 #include <linux/dmi.h>
  47 #include <asm/io.h>
  48
  49 #include "internal.h"
  50
  51 #define ACPI_EC_CLASS                   "embedded_controller"
  52 #define ACPI_EC_DEVICE_NAME             "Embedded Controller"
  53 #define ACPI_EC_FILE_INFO               "info"
  54
  55 /* EC status register */
  56 #define ACPI_EC_FLAG_OBF        0x01    /* Output buffer full */
  57 #define ACPI_EC_FLAG_IBF        0x02    /* Input buffer full */
  58 #define ACPI_EC_FLAG_CMD        0x08    /* Input buffer contains a command */
  59 #define ACPI_EC_FLAG_BURST      0x10    /* burst mode */
  60 #define ACPI_EC_FLAG_SCI        0x20    /* EC-SCI occurred */
  61
  62 /* EC commands */
  63 enum ec_command {
  64         ACPI_EC_COMMAND_READ = 0x80,
  65         ACPI_EC_COMMAND_WRITE = 0x81,
  66         ACPI_EC_BURST_ENABLE = 0x82,
  67         ACPI_EC_BURST_DISABLE = 0x83,
  68         ACPI_EC_COMMAND_QUERY = 0x84,
  69 };
  70
  71 #define ACPI_EC_DELAY           500     /* Wait 500ms max. during EC ops */
  72 #define ACPI_EC_UDELAY_GLK      1000    /* Wait 1ms max. to get global lock */
  73 #define ACPI_EC_MSI_UDELAY      550     /* Wait 550us for MSI EC */
  74 #define ACPI_EC_CLEAR_MAX       100     /* Maximum number of events to query
  75                                          * when trying to clear the EC */
  76
  77 enum {
  78         EC_FLAGS_QUERY_PENDING,         /* Query is pending */
  79         EC_FLAGS_GPE_STORM,             /* GPE storm detected */
  80         EC_FLAGS_HANDLERS_INSTALLED,    /* Handlers for GPE and
  81                                          * OpReg are installed */
  82         EC_FLAGS_BLOCKED,               /* Transactions are blocked */
  83 };
  84
  85 #define ACPI_EC_COMMAND_POLL            0x01 /* Available for command byte */
  86 #define ACPI_EC_COMMAND_COMPLETE        0x02 /* Completed last byte */
  87
  88 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
  89 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
  90 module_param(ec_delay, uint, 0644);
  91 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
  92
  93 /*
  94  * If the number of false interrupts per one transaction exceeds
  95  * this threshold, will think there is a GPE storm happened and
  96  * will disable the GPE for normal transaction.
  97  */
  98 static unsigned int ec_storm_threshold  __read_mostly = 8;
  99 module_param(ec_storm_threshold, uint, 0644);
 100 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
 101
 102 struct acpi_ec_query_handler {
 103         struct list_head node;
 104         acpi_ec_query_func func;
 105         acpi_handle handle;
 106         void *data;
 107         u8 query_bit;
 108         struct kref kref;
 109 };
 110
 111 struct transaction {
 112         const u8 *wdata;
 113         u8 *rdata;
 114         unsigned short irq_count;
 115         u8 command;
 116         u8 wi;
 117         u8 ri;
 118         u8 wlen;
 119         u8 rlen;
 120         u8 flags;
 121 };
 122
 123 struct acpi_ec *boot_ec, *first_ec;
 124 EXPORT_SYMBOL(first_ec);
 125
 126 static int EC_FLAGS_MSI; /* Out-of-spec MSI controller */
 127 static int EC_FLAGS_VALIDATE_ECDT; /* ASUStec ECDTs need to be validated */
 128 static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
 129 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
 130 static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
 131
 132 /* --------------------------------------------------------------------------
 133  *                           Transaction Management
 134  * -------------------------------------------------------------------------- */
 135
 136 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
 137 {
 138         u8 x = inb(ec->command_addr);
 139
 140         pr_debug("EC_SC(R) = 0x%2.2x "
 141                  "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d\n",
 142                  x,
 143                  !!(x & ACPI_EC_FLAG_SCI),
 144                  !!(x & ACPI_EC_FLAG_BURST),
 145                  !!(x & ACPI_EC_FLAG_CMD),
 146                  !!(x & ACPI_EC_FLAG_IBF),
 147                  !!(x & ACPI_EC_FLAG_OBF));
 148         return x;
 149 }
 150
 151 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
 152 {
 153         u8 x = inb(ec->data_addr);
 154
 155         pr_debug("EC_DATA(R) = 0x%2.2x\n", x);
 156         return x;
 157 }
 158
 159 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
 160 {
 161         pr_debug("EC_SC(W) = 0x%2.2x\n", command);
 162         outb(command, ec->command_addr);
 163 }
 164
 165 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
 166 {
 167         pr_debug("EC_DATA(W) = 0x%2.2x\n", data);
 168         outb(data, ec->data_addr);
 169 }
 170
 171 #ifdef DEBUG
 172 static const char *acpi_ec_cmd_string(u8 cmd)
 173 {
 174         switch (cmd) {
 175         case 0x80:
 176                 return "RD_EC";
 177         case 0x81:
 178                 return "WR_EC";
 179         case 0x82:
 180                 return "BE_EC";
 181         case 0x83:
 182                 return "BD_EC";
 183         case 0x84:
 184                 return "QR_EC";
 185         }
 186         return "UNKNOWN";
 187 }
 188 #else
 189 #define acpi_ec_cmd_string(cmd)         "UNDEF"
 190 #endif
 191
 192 static int ec_transaction_completed(struct acpi_ec *ec)
 193 {
 194         unsigned long flags;
 195         int ret = 0;
 196
 197         spin_lock_irqsave(&ec->lock, flags);
 198         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
 199                 ret = 1;
 200         spin_unlock_irqrestore(&ec->lock, flags);
 201         return ret;
 202 }
 203
 204 static void advance_transaction(struct acpi_ec *ec)
 205 {
 206         struct transaction *t;
 207         u8 status;
 208         bool wakeup = false;
 209
 210         pr_debug("===== %s (%d) =====\n",
 211                  in_interrupt() ? "IRQ" : "TASK", smp_processor_id());
 212         status = acpi_ec_read_status(ec);
 213         t = ec->curr;
 214         if (!t)
 215                 goto err;
 216         if (t->flags & ACPI_EC_COMMAND_POLL) {
 217                 if (t->wlen > t->wi) {
 218                         if ((status & ACPI_EC_FLAG_IBF) == 0)
 219                                 acpi_ec_write_data(ec, t->wdata[t->wi++]);
 220                         else
 221                                 goto err;
 222                 } else if (t->rlen > t->ri) {
 223                         if ((status & ACPI_EC_FLAG_OBF) == 1) {
 224                                 t->rdata[t->ri++] = acpi_ec_read_data(ec);
 225                                 if (t->rlen == t->ri) {
 226                                         t->flags |= ACPI_EC_COMMAND_COMPLETE;
 227                                         if (t->command == ACPI_EC_COMMAND_QUERY)
 228                                                 pr_debug("***** Command(%s) hardware completion *****\n",
 229                                                          acpi_ec_cmd_string(t->command));
 230                                         wakeup = true;
 231                                 }
 232                         } else
 233                                 goto err;
 234                 } else if (t->wlen == t->wi &&
 235                            (status & ACPI_EC_FLAG_IBF) == 0) {
 236                         t->flags |= ACPI_EC_COMMAND_COMPLETE;
 237                         wakeup = true;
 238                 }
 239                 goto out;
 240         } else {
 241                 if (EC_FLAGS_QUERY_HANDSHAKE &&
 242                     !(status & ACPI_EC_FLAG_SCI) &&
 243                     (t->command == ACPI_EC_COMMAND_QUERY)) {
 244                         t->flags |= ACPI_EC_COMMAND_POLL;
 245                         t->rdata[t->ri++] = 0x00;
 246                         t->flags |= ACPI_EC_COMMAND_COMPLETE;
 247                         pr_debug("***** Command(%s) software completion *****\n",
 248                                  acpi_ec_cmd_string(t->command));
 249                         wakeup = true;
 250                 } else if ((status & ACPI_EC_FLAG_IBF) == 0) {
 251                         acpi_ec_write_cmd(ec, t->command);
 252                         t->flags |= ACPI_EC_COMMAND_POLL;
 253                 } else
 254                         goto err;
 255                 goto out;
 256         }
 257 err:
 258         /*
 259          * If SCI bit is set, then don't think it's a false IRQ
 260          * otherwise will take a not handled IRQ as a false one.
 261          */
 262         if (!(status & ACPI_EC_FLAG_SCI)) {
 263                 if (in_interrupt() && t)
 264                         ++t->irq_count;
 265         }
 266 out:
 267         if (wakeup && in_interrupt())
 268                 wake_up(&ec->wait);
 269 }
 270
 271 static void start_transaction(struct acpi_ec *ec)
 272 {
 273         ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
 274         ec->curr->flags = 0;
 275         advance_transaction(ec);
 276 }
 277
 278 static int acpi_ec_sync_query(struct acpi_ec *ec, u8 *data);
 279
 280 static int ec_check_sci_sync(struct acpi_ec *ec, u8 state)
 281 {
 282         if (state & ACPI_EC_FLAG_SCI) {
 283                 if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
 284                         return acpi_ec_sync_query(ec, NULL);
 285         }
 286         return 0;
 287 }
 288
 289 static int ec_poll(struct acpi_ec *ec)
 290 {
 291         unsigned long flags;
 292         int repeat = 5; /* number of command restarts */
 293
 294         while (repeat--) {
 295                 unsigned long delay = jiffies +
 296                         msecs_to_jiffies(ec_delay);
 297                 do {
 298                         /* don't sleep with disabled interrupts */
 299                         if (EC_FLAGS_MSI || irqs_disabled()) {
 300                                 udelay(ACPI_EC_MSI_UDELAY);
 301                                 if (ec_transaction_completed(ec))
 302                                         return 0;
 303                         } else {
 304                                 if (wait_event_timeout(ec->wait,
 305                                                 ec_transaction_completed(ec),
 306                                                 msecs_to_jiffies(1)))
 307                                         return 0;
 308                         }
 309                         spin_lock_irqsave(&ec->lock, flags);
 310                         advance_transaction(ec);
 311                         spin_unlock_irqrestore(&ec->lock, flags);
 312                 } while (time_before(jiffies, delay));
 313                 pr_debug("controller reset, restart transaction\n");
 314                 spin_lock_irqsave(&ec->lock, flags);
 315                 start_transaction(ec);
 316                 spin_unlock_irqrestore(&ec->lock, flags);
 317         }
 318         return -ETIME;
 319 }
 320
 321 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
 322                                         struct transaction *t)
 323 {
 324         unsigned long tmp;
 325         int ret = 0;
 326
 327         if (EC_FLAGS_MSI)
 328                 udelay(ACPI_EC_MSI_UDELAY);
 329         /* start transaction */
 330         spin_lock_irqsave(&ec->lock, tmp);
 331         /* following two actions should be kept atomic */
 332         ec->curr = t;
 333         pr_debug("***** Command(%s) started *****\n",
 334                  acpi_ec_cmd_string(t->command));
 335         start_transaction(ec);
 336         if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
 337                 clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
 338                 pr_debug("***** Event stopped *****\n");
 339         }
 340         spin_unlock_irqrestore(&ec->lock, tmp);
 341         ret = ec_poll(ec);
 342         spin_lock_irqsave(&ec->lock, tmp);
 343         pr_debug("***** Command(%s) stopped *****\n",
 344                  acpi_ec_cmd_string(t->command));
 345         ec->curr = NULL;
 346         spin_unlock_irqrestore(&ec->lock, tmp);
 347         return ret;
 348 }
 349
 350 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
 351 {
 352         int status;
 353         u32 glk;
 354
 355         if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
 356                 return -EINVAL;
 357         if (t->rdata)
 358                 memset(t->rdata, 0, t->rlen);
 359         mutex_lock(&ec->mutex);
 360         if (test_bit(EC_FLAGS_BLOCKED, &ec->flags)) {
 361                 status = -EINVAL;
 362                 goto unlock;
 363         }
 364         if (ec->global_lock) {
 365                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
 366                 if (ACPI_FAILURE(status)) {
 367                         status = -ENODEV;
 368                         goto unlock;
 369                 }
 370         }
 371         /* disable GPE during transaction if storm is detected */
 372         if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
 373                 /* It has to be disabled, so that it doesn't trigger. */
 374                 acpi_disable_gpe(NULL, ec->gpe);
 375         }
 376
 377         status = acpi_ec_transaction_unlocked(ec, t);
 378
 379         /* check if we received SCI during transaction */
 380         ec_check_sci_sync(ec, acpi_ec_read_status(ec));
 381         if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
 382                 msleep(1);
 383                 /* It is safe to enable the GPE outside of the transaction. */
 384                 acpi_enable_gpe(NULL, ec->gpe);
 385         } else if (t->irq_count > ec_storm_threshold) {
 386                 pr_info("GPE storm detected(%d GPEs), "
 387                         "transactions will use polling mode\n",
 388                         t->irq_count);
 389                 set_bit(EC_FLAGS_GPE_STORM, &ec->flags);
 390         }
 391         if (ec->global_lock)
 392                 acpi_release_global_lock(glk);
 393 unlock:
 394         mutex_unlock(&ec->mutex);
 395         return status;
 396 }
 397
 398 static int acpi_ec_burst_enable(struct acpi_ec *ec)
 399 {
 400         u8 d;
 401         struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
 402                                 .wdata = NULL, .rdata = &d,
 403                                 .wlen = 0, .rlen = 1};
 404
 405         return acpi_ec_transaction(ec, &t);
 406 }
 407
 408 static int acpi_ec_burst_disable(struct acpi_ec *ec)
 409 {
 410         struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
 411                                 .wdata = NULL, .rdata = NULL,
 412                                 .wlen = 0, .rlen = 0};
 413
 414         return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
 415                                 acpi_ec_transaction(ec, &t) : 0;
 416 }
 417
 418 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
 419 {
 420         int result;
 421         u8 d;
 422         struct transaction t = {.command = ACPI_EC_COMMAND_READ,
 423                                 .wdata = &address, .rdata = &d,
 424                                 .wlen = 1, .rlen = 1};
 425
 426         result = acpi_ec_transaction(ec, &t);
 427         *data = d;
 428         return result;
 429 }
 430
 431 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
 432 {
 433         u8 wdata[2] = { address, data };
 434         struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
 435                                 .wdata = wdata, .rdata = NULL,
 436                                 .wlen = 2, .rlen = 0};
 437
 438         return acpi_ec_transaction(ec, &t);
 439 }
 440
 441 int ec_read(u8 addr, u8 *val)
 442 {
 443         int err;
 444         u8 temp_data;
 445
 446         if (!first_ec)
 447                 return -ENODEV;
 448
 449         err = acpi_ec_read(first_ec, addr, &temp_data);
 450
 451         if (!err) {
 452                 *val = temp_data;
 453                 return 0;
 454         }
 455         return err;
 456 }
 457 EXPORT_SYMBOL(ec_read);
 458
 459 int ec_write(u8 addr, u8 val)
 460 {
 461         int err;
 462
 463         if (!first_ec)
 464                 return -ENODEV;
 465
 466         err = acpi_ec_write(first_ec, addr, val);
 467
 468         return err;
 469 }
 470 EXPORT_SYMBOL(ec_write);
 471
 472 int ec_transaction(u8 command,
 473                    const u8 *wdata, unsigned wdata_len,
 474                    u8 *rdata, unsigned rdata_len)
 475 {
 476         struct transaction t = {.command = command,
 477                                 .wdata = wdata, .rdata = rdata,
 478                                 .wlen = wdata_len, .rlen = rdata_len};
 479
 480         if (!first_ec)
 481                 return -ENODEV;
 482
 483         return acpi_ec_transaction(first_ec, &t);
 484 }
 485 EXPORT_SYMBOL(ec_transaction);
 486
 487 /* Get the handle to the EC device */
 488 acpi_handle ec_get_handle(void)
 489 {
 490         if (!first_ec)
 491                 return NULL;
 492         return first_ec->handle;
 493 }
 494 EXPORT_SYMBOL(ec_get_handle);
 495
 496 /*
 497  * Process _Q events that might have accumulated in the EC.
 498  * Run with locked ec mutex.
 499  */
 500 static void acpi_ec_clear(struct acpi_ec *ec)
 501 {
 502         int i, status;
 503         u8 value = 0;
 504
 505         for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
 506                 status = acpi_ec_sync_query(ec, &value);
 507                 if (status || !value)
 508                         break;
 509         }
 510
 511         if (unlikely(i == ACPI_EC_CLEAR_MAX))
 512                 pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
 513         else
 514                 pr_info("%d stale EC events cleared\n", i);
 515 }
 516
 517 void acpi_ec_block_transactions(void)
 518 {
 519         struct acpi_ec *ec = first_ec;
 520
 521         if (!ec)
 522                 return;
 523
 524         mutex_lock(&ec->mutex);
 525         /* Prevent transactions from being carried out */
 526         set_bit(EC_FLAGS_BLOCKED, &ec->flags);
 527         mutex_unlock(&ec->mutex);
 528 }
 529
 530 void acpi_ec_unblock_transactions(void)
 531 {
 532         struct acpi_ec *ec = first_ec;
 533
 534         if (!ec)
 535                 return;
 536
 537         mutex_lock(&ec->mutex);
 538         /* Allow transactions to be carried out again */
 539         clear_bit(EC_FLAGS_BLOCKED, &ec->flags);
 540
 541         if (EC_FLAGS_CLEAR_ON_RESUME)
 542                 acpi_ec_clear(ec);
 543
 544         mutex_unlock(&ec->mutex);
 545 }
 546
 547 void acpi_ec_unblock_transactions_early(void)
 548 {
 549         /*
 550          * Allow transactions to happen again (this function is called from
 551          * atomic context during wakeup, so we don't need to acquire the mutex).
 552          */
 553         if (first_ec)
 554                 clear_bit(EC_FLAGS_BLOCKED, &first_ec->flags);
 555 }
 556
 557 static int acpi_ec_query_unlocked(struct acpi_ec *ec, u8 *data)
 558 {
 559         int result;
 560         u8 d;
 561         struct transaction t = {.command = ACPI_EC_COMMAND_QUERY,
 562                                 .wdata = NULL, .rdata = &d,
 563                                 .wlen = 0, .rlen = 1};
 564
 565         if (!ec || !data)
 566                 return -EINVAL;
 567         /*
 568          * Query the EC to find out which _Qxx method we need to evaluate.
 569          * Note that successful completion of the query causes the ACPI_EC_SCI
 570          * bit to be cleared (and thus clearing the interrupt source).
 571          */
 572         result = acpi_ec_transaction_unlocked(ec, &t);
 573         if (result)
 574                 return result;
 575         if (!d)
 576                 return -ENODATA;
 577         *data = d;
 578         return 0;
 579 }
 580
 581 /* --------------------------------------------------------------------------
 582                                 Event Management
 583    -------------------------------------------------------------------------- */
 584 static struct acpi_ec_query_handler *
 585 acpi_ec_get_query_handler(struct acpi_ec_query_handler *handler)
 586 {
 587         if (handler)
 588                 kref_get(&handler->kref);
 589         return handler;
 590 }
 591
 592 static void acpi_ec_query_handler_release(struct kref *kref)
 593 {
 594         struct acpi_ec_query_handler *handler =
 595                 container_of(kref, struct acpi_ec_query_handler, kref);
 596
 597         kfree(handler);
 598 }
 599
 600 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
 601 {
 602         kref_put(&handler->kref, acpi_ec_query_handler_release);
 603 }
 604
 605 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
 606                               acpi_handle handle, acpi_ec_query_func func,
 607                               void *data)
 608 {
 609         struct acpi_ec_query_handler *handler =
 610             kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
 611
 612         if (!handler)
 613                 return -ENOMEM;
 614
 615         handler->query_bit = query_bit;
 616         handler->handle = handle;
 617         handler->func = func;
 618         handler->data = data;
 619         mutex_lock(&ec->mutex);
 620         kref_init(&handler->kref);
 621         list_add(&handler->node, &ec->list);
 622         mutex_unlock(&ec->mutex);
 623         return 0;
 624 }
 625 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
 626
 627 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
 628 {
 629         struct acpi_ec_query_handler *handler, *tmp;
 630         LIST_HEAD(free_list);
 631
 632         mutex_lock(&ec->mutex);
 633         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
 634                 if (query_bit == handler->query_bit) {
 635                         list_del_init(&handler->node);
 636                         list_add(&handler->node, &free_list);
 637                 }
 638         }
 639         mutex_unlock(&ec->mutex);
 640         list_for_each_entry(handler, &free_list, node)
 641                 acpi_ec_put_query_handler(handler);
 642 }
 643 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
 644
 645 static void acpi_ec_run(void *cxt)
 646 {
 647         struct acpi_ec_query_handler *handler = cxt;
 648
 649         if (!handler)
 650                 return;
 651         pr_debug("##### Query(0x%02x) started #####\n", handler->query_bit);
 652         if (handler->func)
 653                 handler->func(handler->data);
 654         else if (handler->handle)
 655                 acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
 656         pr_debug("##### Query(0x%02x) stopped #####\n", handler->query_bit);
 657         acpi_ec_put_query_handler(handler);
 658 }
 659
 660 static int acpi_ec_sync_query(struct acpi_ec *ec, u8 *data)
 661 {
 662         u8 value = 0;
 663         int status;
 664         struct acpi_ec_query_handler *handler;
 665
 666         status = acpi_ec_query_unlocked(ec, &value);
 667         if (data)
 668                 *data = value;
 669         if (status)
 670                 return status;
 671
 672         list_for_each_entry(handler, &ec->list, node) {
 673                 if (value == handler->query_bit) {
 674                         /* have custom handler for this bit */
 675                         handler = acpi_ec_get_query_handler(handler);
 676                         pr_debug("##### Query(0x%02x) scheduled #####\n",
 677                                  handler->query_bit);
 678                         return acpi_os_execute((handler->func) ?
 679                                 OSL_NOTIFY_HANDLER : OSL_GPE_HANDLER,
 680                                 acpi_ec_run, handler);
 681                 }
 682         }
 683         return 0;
 684 }
 685
 686 static void acpi_ec_gpe_query(void *ec_cxt)
 687 {
 688         struct acpi_ec *ec = ec_cxt;
 689
 690         if (!ec)
 691                 return;
 692         mutex_lock(&ec->mutex);
 693         acpi_ec_sync_query(ec, NULL);
 694         mutex_unlock(&ec->mutex);
 695 }
 696
 697 static int ec_check_sci(struct acpi_ec *ec, u8 state)
 698 {
 699         if (state & ACPI_EC_FLAG_SCI) {
 700                 if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
 701                         pr_debug("***** Event started *****\n");
 702                         return acpi_os_execute(OSL_NOTIFY_HANDLER,
 703                                 acpi_ec_gpe_query, ec);
 704                 }
 705         }
 706         return 0;
 707 }
 708
 709 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
 710         u32 gpe_number, void *data)
 711 {
 712         unsigned long flags;
 713         struct acpi_ec *ec = data;
 714
 715         spin_lock_irqsave(&ec->lock, flags);
 716         advance_transaction(ec);
 717         spin_unlock_irqrestore(&ec->lock, flags);
 718         ec_check_sci(ec, acpi_ec_read_status(ec));
 719         return ACPI_INTERRUPT_HANDLED | ACPI_REENABLE_GPE;
 720 }
 721
 722 /* --------------------------------------------------------------------------
 723  *                           Address Space Management
 724  * -------------------------------------------------------------------------- */
 725
 726 static acpi_status
 727 acpi_ec_space_handler(u32 function, acpi_physical_address address,
 728                       u32 bits, u64 *value64,
 729                       void *handler_context, void *region_context)
 730 {
 731         struct acpi_ec *ec = handler_context;
 732         int result = 0, i, bytes = bits / 8;
 733         u8 *value = (u8 *)value64;
 734
 735         if ((address > 0xFF) || !value || !handler_context)
 736                 return AE_BAD_PARAMETER;
 737
 738         if (function != ACPI_READ && function != ACPI_WRITE)
 739                 return AE_BAD_PARAMETER;
 740
 741         if (EC_FLAGS_MSI || bits > 8)
 742                 acpi_ec_burst_enable(ec);
 743
 744         for (i = 0; i < bytes; ++i, ++address, ++value)
 745                 result = (function == ACPI_READ) ?
 746                         acpi_ec_read(ec, address, value) :
 747                         acpi_ec_write(ec, address, *value);
 748
 749         if (EC_FLAGS_MSI || bits > 8)
 750                 acpi_ec_burst_disable(ec);
 751
 752         switch (result) {
 753         case -EINVAL:
 754                 return AE_BAD_PARAMETER;
 755         case -ENODEV:
 756                 return AE_NOT_FOUND;
 757         case -ETIME:
 758                 return AE_TIME;
 759         default:
 760                 return AE_OK;
 761         }
 762 }
 763
 764 /* --------------------------------------------------------------------------
 765  *                             Driver Interface
 766  * -------------------------------------------------------------------------- */
 767
 768 static acpi_status
 769 ec_parse_io_ports(struct acpi_resource *resource, void *context);
 770
 771 static struct acpi_ec *make_acpi_ec(void)
 772 {
 773         struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
 774
 775         if (!ec)
 776                 return NULL;
 777         ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
 778         mutex_init(&ec->mutex);
 779         init_waitqueue_head(&ec->wait);
 780         INIT_LIST_HEAD(&ec->list);
 781         spin_lock_init(&ec->lock);
 782         return ec;
 783 }
 784
 785 static acpi_status
 786 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
 787                                void *context, void **return_value)
 788 {
 789         char node_name[5];
 790         struct acpi_buffer buffer = { sizeof(node_name), node_name };
 791         struct acpi_ec *ec = context;
 792         int value = 0;
 793         acpi_status status;
 794
 795         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
 796
 797         if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
 798                 acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
 799         return AE_OK;
 800 }
 801
 802 static acpi_status
 803 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
 804 {
 805         acpi_status status;
 806         unsigned long long tmp = 0;
 807         struct acpi_ec *ec = context;
 808
 809         /* clear addr values, ec_parse_io_ports depend on it */
 810         ec->command_addr = ec->data_addr = 0;
 811
 812         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
 813                                      ec_parse_io_ports, ec);
 814         if (ACPI_FAILURE(status))
 815                 return status;
 816
 817         /* Get GPE bit assignment (EC events). */
 818         /* TODO: Add support for _GPE returning a package */
 819         status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
 820         if (ACPI_FAILURE(status))
 821                 return status;
 822         ec->gpe = tmp;
 823         /* Use the global lock for all EC transactions? */
 824         tmp = 0;
 825         acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
 826         ec->global_lock = tmp;
 827         ec->handle = handle;
 828         return AE_CTRL_TERMINATE;
 829 }
 830
 831 static int ec_install_handlers(struct acpi_ec *ec)
 832 {
 833         acpi_status status;
 834
 835         if (test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
 836                 return 0;
 837         status = acpi_install_gpe_handler(NULL, ec->gpe,
 838                                   ACPI_GPE_EDGE_TRIGGERED,
 839                                   &acpi_ec_gpe_handler, ec);
 840         if (ACPI_FAILURE(status))
 841                 return -ENODEV;
 842
 843         acpi_enable_gpe(NULL, ec->gpe);
 844         status = acpi_install_address_space_handler(ec->handle,
 845                                                     ACPI_ADR_SPACE_EC,
 846                                                     &acpi_ec_space_handler,
 847                                                     NULL, ec);
 848         if (ACPI_FAILURE(status)) {
 849                 if (status == AE_NOT_FOUND) {
 850                         /*
 851                          * Maybe OS fails in evaluating the _REG object.
 852                          * The AE_NOT_FOUND error will be ignored and OS
 853                          * continue to initialize EC.
 854                          */
 855                         pr_err("Fail in evaluating the _REG object"
 856                                 " of EC device. Broken bios is suspected.\n");
 857                 } else {
 858                         acpi_disable_gpe(NULL, ec->gpe);
 859                         acpi_remove_gpe_handler(NULL, ec->gpe,
 860                                 &acpi_ec_gpe_handler);
 861                         return -ENODEV;
 862                 }
 863         }
 864
 865         set_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
 866         return 0;
 867 }
 868
 869 static void ec_remove_handlers(struct acpi_ec *ec)
 870 {
 871         if (!test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
 872                 return;
 873         acpi_disable_gpe(NULL, ec->gpe);
 874         if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
 875                                 ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
 876                 pr_err("failed to remove space handler\n");
 877         if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
 878                                 &acpi_ec_gpe_handler)))
 879                 pr_err("failed to remove gpe handler\n");
 880         clear_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
 881 }
 882
 883 static int acpi_ec_add(struct acpi_device *device)
 884 {
 885         struct acpi_ec *ec = NULL;
 886         int ret;
 887
 888         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
 889         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
 890
 891         /* Check for boot EC */
 892         if (boot_ec &&
 893             (boot_ec->handle == device->handle ||
 894              boot_ec->handle == ACPI_ROOT_OBJECT)) {
 895                 ec = boot_ec;
 896                 boot_ec = NULL;
 897         } else {
 898                 ec = make_acpi_ec();
 899                 if (!ec)
 900                         return -ENOMEM;
 901         }
 902         if (ec_parse_device(device->handle, 0, ec, NULL) !=
 903                 AE_CTRL_TERMINATE) {
 904                         kfree(ec);
 905                         return -EINVAL;
 906         }
 907
 908         /* Find and register all query methods */
 909         acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
 910                             acpi_ec_register_query_methods, NULL, ec, NULL);
 911
 912         if (!first_ec)
 913                 first_ec = ec;
 914         device->driver_data = ec;
 915
 916         ret = !!request_region(ec->data_addr, 1, "EC data");
 917         WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
 918         ret = !!request_region(ec->command_addr, 1, "EC cmd");
 919         WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
 920
 921         pr_info("GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
 922                           ec->gpe, ec->command_addr, ec->data_addr);
 923
 924         ret = ec_install_handlers(ec);
 925
 926         /* EC is fully operational, allow queries */
 927         clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
 928
 929         /* Clear stale _Q events if hardware might require that */
 930         if (EC_FLAGS_CLEAR_ON_RESUME) {
 931                 mutex_lock(&ec->mutex);
 932                 acpi_ec_clear(ec);
 933                 mutex_unlock(&ec->mutex);
 934         }
 935         return ret;
 936 }
 937
 938 static int acpi_ec_remove(struct acpi_device *device)
 939 {
 940         struct acpi_ec *ec;
 941         struct acpi_ec_query_handler *handler, *tmp;
 942
 943         if (!device)
 944                 return -EINVAL;
 945
 946         ec = acpi_driver_data(device);
 947         ec_remove_handlers(ec);
 948         mutex_lock(&ec->mutex);
 949         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
 950                 list_del(&handler->node);
 951                 kfree(handler);
 952         }
 953         mutex_unlock(&ec->mutex);
 954         release_region(ec->data_addr, 1);
 955         release_region(ec->command_addr, 1);
 956         device->driver_data = NULL;
 957         if (ec == first_ec)
 958                 first_ec = NULL;
 959         kfree(ec);
 960         return 0;
 961 }
 962
 963 static acpi_status
 964 ec_parse_io_ports(struct acpi_resource *resource, void *context)
 965 {
 966         struct acpi_ec *ec = context;
 967
 968         if (resource->type != ACPI_RESOURCE_TYPE_IO)
 969                 return AE_OK;
 970
 971         /*
 972          * The first address region returned is the data port, and
 973          * the second address region returned is the status/command
 974          * port.
 975          */
 976         if (ec->data_addr == 0)
 977                 ec->data_addr = resource->data.io.minimum;
 978         else if (ec->command_addr == 0)
 979                 ec->command_addr = resource->data.io.minimum;
 980         else
 981                 return AE_CTRL_TERMINATE;
 982
 983         return AE_OK;
 984 }
 985
 986 int __init acpi_boot_ec_enable(void)
 987 {
 988         if (!boot_ec || test_bit(EC_FLAGS_HANDLERS_INSTALLED, &boot_ec->flags))
 989                 return 0;
 990         if (!ec_install_handlers(boot_ec)) {
 991                 first_ec = boot_ec;
 992                 return 0;
 993         }
 994         return -EFAULT;
 995 }
 996
 997 static const struct acpi_device_id ec_device_ids[] = {
 998         {"PNP0C09", 0},
 999         {"", 0},
1000 };
1001
1002 /* Some BIOS do not survive early DSDT scan, skip it */
1003 static int ec_skip_dsdt_scan(const struct dmi_system_id *id)
1004 {
1005         EC_FLAGS_SKIP_DSDT_SCAN = 1;
1006         return 0;
1007 }
1008
1009 /* ASUStek often supplies us with broken ECDT, validate it */
1010 static int ec_validate_ecdt(const struct dmi_system_id *id)
1011 {
1012         EC_FLAGS_VALIDATE_ECDT = 1;
1013         return 0;
1014 }
1015
1016 /* MSI EC needs special treatment, enable it */
1017 static int ec_flag_msi(const struct dmi_system_id *id)
1018 {
1019         pr_debug("Detected MSI hardware, enabling workarounds.\n");
1020         EC_FLAGS_MSI = 1;
1021         EC_FLAGS_VALIDATE_ECDT = 1;
1022         return 0;
1023 }
1024
1025 /*
1026  * Clevo M720 notebook actually works ok with IRQ mode, if we lifted
1027  * the GPE storm threshold back to 20
1028  */
1029 static int ec_enlarge_storm_threshold(const struct dmi_system_id *id)
1030 {
1031         pr_debug("Setting the EC GPE storm threshold to 20\n");
1032         ec_storm_threshold  = 20;
1033         return 0;
1034 }
1035
1036 /*
1037  * Acer EC firmware refuses to respond QR_EC when SCI_EVT is not set, for
1038  * which case, we complete the QR_EC without issuing it to the firmware.
1039  * https://bugzilla.kernel.org/show_bug.cgi?id=86211
1040  */
1041 static int ec_flag_query_handshake(const struct dmi_system_id *id)
1042 {
1043         pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
1044         EC_FLAGS_QUERY_HANDSHAKE = 1;
1045         return 0;
1046 }
1047
1048 /*
1049  * On some hardware it is necessary to clear events accumulated by the EC during
1050  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1051  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1052  *
1053  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1054  *
1055  * Ideally, the EC should also be instructed NOT to accumulate events during
1056  * sleep (which Windows seems to do somehow), but the interface to control this
1057  * behaviour is not known at this time.
1058  *
1059  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1060  * however it is very likely that other Samsung models are affected.
1061  *
1062  * On systems which don't accumulate _Q events during sleep, this extra check
1063  * should be harmless.
1064  */
1065 static int ec_clear_on_resume(const struct dmi_system_id *id)
1066 {
1067         pr_debug("Detected system needing EC poll on resume.\n");
1068         EC_FLAGS_CLEAR_ON_RESUME = 1;
1069         return 0;
1070 }
1071
1072 static struct dmi_system_id ec_dmi_table[] __initdata = {
1073         {
1074         ec_skip_dsdt_scan, "Compal JFL92", {
1075         DMI_MATCH(DMI_BIOS_VENDOR, "COMPAL"),
1076         DMI_MATCH(DMI_BOARD_NAME, "JFL92") }, NULL},
1077         {
1078         ec_flag_msi, "MSI hardware", {
1079         DMI_MATCH(DMI_BIOS_VENDOR, "Micro-Star")}, NULL},
1080         {
1081         ec_flag_msi, "MSI hardware", {
1082         DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star")}, NULL},
1083         {
1084         ec_flag_msi, "MSI hardware", {
1085         DMI_MATCH(DMI_CHASSIS_VENDOR, "MICRO-Star")}, NULL},
1086         {
1087         ec_flag_msi, "MSI hardware", {
1088         DMI_MATCH(DMI_CHASSIS_VENDOR, "MICRO-STAR")}, NULL},
1089         {
1090         ec_flag_msi, "Quanta hardware", {
1091         DMI_MATCH(DMI_SYS_VENDOR, "Quanta"),
1092         DMI_MATCH(DMI_PRODUCT_NAME, "TW8/SW8/DW8"),}, NULL},
1093         {
1094         ec_flag_msi, "Quanta hardware", {
1095         DMI_MATCH(DMI_SYS_VENDOR, "Quanta"),
1096         DMI_MATCH(DMI_PRODUCT_NAME, "TW9/SW9"),}, NULL},
1097         {
1098         ec_flag_msi, "Clevo W350etq", {
1099         DMI_MATCH(DMI_SYS_VENDOR, "CLEVO CO."),
1100         DMI_MATCH(DMI_PRODUCT_NAME, "W35_37ET"),}, NULL},
1101         {
1102         ec_validate_ecdt, "ASUS hardware", {
1103         DMI_MATCH(DMI_BIOS_VENDOR, "ASUS") }, NULL},
1104         {
1105         ec_validate_ecdt, "ASUS hardware", {
1106         DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer Inc.") }, NULL},
1107         {
1108         ec_enlarge_storm_threshold, "CLEVO hardware", {
1109         DMI_MATCH(DMI_SYS_VENDOR, "CLEVO Co."),
1110         DMI_MATCH(DMI_PRODUCT_NAME, "M720T/M730T"),}, NULL},
1111         {
1112         ec_skip_dsdt_scan, "HP Folio 13", {
1113         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
1114         DMI_MATCH(DMI_PRODUCT_NAME, "HP Folio 13"),}, NULL},
1115         {
1116         ec_validate_ecdt, "ASUS hardware", {
1117         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTek Computer Inc."),
1118         DMI_MATCH(DMI_PRODUCT_NAME, "L4R"),}, NULL},
1119         {
1120         ec_clear_on_resume, "Samsung hardware", {
1121         DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1122         {
1123         ec_flag_query_handshake, "Acer hardware", {
1124         DMI_MATCH(DMI_SYS_VENDOR, "Acer"), }, NULL},
1125         {},
1126 };
1127
1128 int __init acpi_ec_ecdt_probe(void)
1129 {
1130         acpi_status status;
1131         struct acpi_ec *saved_ec = NULL;
1132         struct acpi_table_ecdt *ecdt_ptr;
1133
1134         boot_ec = make_acpi_ec();
1135         if (!boot_ec)
1136                 return -ENOMEM;
1137         /*
1138          * Generate a boot ec context
1139          */
1140         dmi_check_system(ec_dmi_table);
1141         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1142                                 (struct acpi_table_header **)&ecdt_ptr);
1143         if (ACPI_SUCCESS(status)) {
1144                 pr_info("EC description table is found, configuring boot EC\n");
1145                 boot_ec->command_addr = ecdt_ptr->control.address;
1146                 boot_ec->data_addr = ecdt_ptr->data.address;
1147                 boot_ec->gpe = ecdt_ptr->gpe;
1148                 boot_ec->handle = ACPI_ROOT_OBJECT;
1149                 acpi_get_handle(ACPI_ROOT_OBJECT, ecdt_ptr->id,
1150                                 &boot_ec->handle);
1151                 /* Don't trust ECDT, which comes from ASUSTek */
1152                 if (!EC_FLAGS_VALIDATE_ECDT)
1153                         goto install;
1154                 saved_ec = kmemdup(boot_ec, sizeof(struct acpi_ec), GFP_KERNEL);
1155                 if (!saved_ec)
1156                         return -ENOMEM;
1157         /* fall through */
1158         }
1159
1160         if (EC_FLAGS_SKIP_DSDT_SCAN) {
1161                 kfree(saved_ec);
1162                 return -ENODEV;
1163         }
1164
1165         /* This workaround is needed only on some broken machines,
1166          * which require early EC, but fail to provide ECDT */
1167         pr_debug("Look up EC in DSDT\n");
1168         status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device,
1169                                         boot_ec, NULL);
1170         /* Check that acpi_get_devices actually find something */
1171         if (ACPI_FAILURE(status) || !boot_ec->handle)
1172                 goto error;
1173         if (saved_ec) {
1174                 /* try to find good ECDT from ASUSTek */
1175                 if (saved_ec->command_addr != boot_ec->command_addr ||
1176                     saved_ec->data_addr != boot_ec->data_addr ||
1177                     saved_ec->gpe != boot_ec->gpe ||
1178                     saved_ec->handle != boot_ec->handle)
1179                         pr_info("ASUSTek keeps feeding us with broken "
1180                         "ECDT tables, which are very hard to workaround. "
1181                         "Trying to use DSDT EC info instead. Please send "
1182                         "output of acpidump to linux-acpi@vger.kernel.org\n");
1183                 kfree(saved_ec);
1184                 saved_ec = NULL;
1185         } else {
1186                 /* We really need to limit this workaround, the only ASUS,
1187                 * which needs it, has fake EC._INI method, so use it as flag.
1188                 * Keep boot_ec struct as it will be needed soon.
1189                 */
1190                 if (!dmi_name_in_vendors("ASUS") ||
1191                     !acpi_has_method(boot_ec->handle, "_INI"))
1192                         return -ENODEV;
1193         }
1194 install:
1195         if (!ec_install_handlers(boot_ec)) {
1196                 first_ec = boot_ec;
1197                 return 0;
1198         }
1199 error:
1200         kfree(boot_ec);
1201         kfree(saved_ec);
1202         boot_ec = NULL;
1203         return -ENODEV;
1204 }
1205
1206 static struct acpi_driver acpi_ec_driver = {
1207         .name = "ec",
1208         .class = ACPI_EC_CLASS,
1209         .ids = ec_device_ids,
1210         .ops = {
1211                 .add = acpi_ec_add,
1212                 .remove = acpi_ec_remove,
1213                 },
1214 };
1215
1216 int __init acpi_ec_init(void)
1217 {
1218         int result = 0;
1219
1220         /* Now register the driver for the EC */
1221         result = acpi_bus_register_driver(&acpi_ec_driver);
1222         if (result < 0)
1223                 return -ENODEV;
1224
1225         return result;
1226 }
1227
1228 /* EC driver currently not unloadable */
1229 #if 0
1230 static void __exit acpi_ec_exit(void)
1231 {
1232
1233         acpi_bus_unregister_driver(&acpi_ec_driver);
1234 }
1235 #endif  /* 0 */