drivers/acpi/ec.c

   1 /*
   2  *  ec.c - ACPI Embedded Controller Driver (v3)
   3  *
   4  *  Copyright (C) 2001-2015 Intel Corporation
   5  *    Author: 2014, 2015 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_UDELAY_POLL     1000    /* Wait 1ms for EC transaction polling */
  75 #define ACPI_EC_CLEAR_MAX       100     /* Maximum number of events to query
  76                                          * when trying to clear the EC */
  77
  78 enum {
  79         EC_FLAGS_EVENT_ENABLED,         /* Event is enabled */
  80         EC_FLAGS_EVENT_PENDING,         /* Event is pending */
  81         EC_FLAGS_EVENT_DETECTED,        /* Event is detected */
  82         EC_FLAGS_HANDLERS_INSTALLED,    /* Handlers for GPE and
  83                                          * OpReg are installed */
  84         EC_FLAGS_STARTED,               /* Driver is started */
  85         EC_FLAGS_STOPPED,               /* Driver is stopped */
  86         EC_FLAGS_COMMAND_STORM,         /* GPE storms occurred to the
  87                                          * current command processing */
  88 };
  89
  90 #define ACPI_EC_COMMAND_POLL            0x01 /* Available for command byte */
  91 #define ACPI_EC_COMMAND_COMPLETE        0x02 /* Completed last byte */
  92
  93 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
  94 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
  95 module_param(ec_delay, uint, 0644);
  96 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
  97
  98 /*
  99  * If the number of false interrupts per one transaction exceeds
 100  * this threshold, will think there is a GPE storm happened and
 101  * will disable the GPE for normal transaction.
 102  */
 103 static unsigned int ec_storm_threshold  __read_mostly = 8;
 104 module_param(ec_storm_threshold, uint, 0644);
 105 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
 106
 107 struct acpi_ec_query_handler {
 108         struct list_head node;
 109         acpi_ec_query_func func;
 110         acpi_handle handle;
 111         void *data;
 112         u8 query_bit;
 113         struct kref kref;
 114 };
 115
 116 struct transaction {
 117         const u8 *wdata;
 118         u8 *rdata;
 119         unsigned short irq_count;
 120         u8 command;
 121         u8 wi;
 122         u8 ri;
 123         u8 wlen;
 124         u8 rlen;
 125         u8 flags;
 126         unsigned long timestamp;
 127 };
 128
 129 static int acpi_ec_query(struct acpi_ec *ec, u8 *data);
 130 static void advance_transaction(struct acpi_ec *ec);
 131
 132 struct acpi_ec *boot_ec, *first_ec;
 133 EXPORT_SYMBOL(first_ec);
 134
 135 static int EC_FLAGS_MSI; /* Out-of-spec MSI controller */
 136 static int EC_FLAGS_VALIDATE_ECDT; /* ASUStec ECDTs need to be validated */
 137 static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
 138 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
 139 static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
 140
 141 /* --------------------------------------------------------------------------
 142  *                           Device Flags
 143  * -------------------------------------------------------------------------- */
 144
 145 static bool acpi_ec_started(struct acpi_ec *ec)
 146 {
 147         return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
 148                !test_bit(EC_FLAGS_STOPPED, &ec->flags);
 149 }
 150
 151 static bool acpi_ec_flushed(struct acpi_ec *ec)
 152 {
 153         return ec->reference_count == 1;
 154 }
 155
 156 static bool acpi_ec_has_pending_event(struct acpi_ec *ec)
 157 {
 158         return test_bit(EC_FLAGS_EVENT_DETECTED, &ec->flags) ||
 159                test_bit(EC_FLAGS_EVENT_PENDING, &ec->flags);
 160 }
 161
 162 /* --------------------------------------------------------------------------
 163  *                           EC Registers
 164  * -------------------------------------------------------------------------- */
 165
 166 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
 167 {
 168         u8 x = inb(ec->command_addr);
 169
 170         pr_debug("EC_SC(R) = 0x%2.2x "
 171                  "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d\n",
 172                  x,
 173                  !!(x & ACPI_EC_FLAG_SCI),
 174                  !!(x & ACPI_EC_FLAG_BURST),
 175                  !!(x & ACPI_EC_FLAG_CMD),
 176                  !!(x & ACPI_EC_FLAG_IBF),
 177                  !!(x & ACPI_EC_FLAG_OBF));
 178         return x;
 179 }
 180
 181 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
 182 {
 183         u8 x = inb(ec->data_addr);
 184
 185         ec->curr->timestamp = jiffies;
 186         pr_debug("EC_DATA(R) = 0x%2.2x\n", x);
 187         return x;
 188 }
 189
 190 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
 191 {
 192         pr_debug("EC_SC(W) = 0x%2.2x\n", command);
 193         outb(command, ec->command_addr);
 194         ec->curr->timestamp = jiffies;
 195 }
 196
 197 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
 198 {
 199         pr_debug("EC_DATA(W) = 0x%2.2x\n", data);
 200         outb(data, ec->data_addr);
 201         ec->curr->timestamp = jiffies;
 202 }
 203
 204 #ifdef DEBUG
 205 static const char *acpi_ec_cmd_string(u8 cmd)
 206 {
 207         switch (cmd) {
 208         case 0x80:
 209                 return "RD_EC";
 210         case 0x81:
 211                 return "WR_EC";
 212         case 0x82:
 213                 return "BE_EC";
 214         case 0x83:
 215                 return "BD_EC";
 216         case 0x84:
 217                 return "QR_EC";
 218         }
 219         return "UNKNOWN";
 220 }
 221 #else
 222 #define acpi_ec_cmd_string(cmd)         "UNDEF"
 223 #endif
 224
 225 /* --------------------------------------------------------------------------
 226  *                           GPE Registers
 227  * -------------------------------------------------------------------------- */
 228
 229 static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec)
 230 {
 231         acpi_event_status gpe_status = 0;
 232
 233         (void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
 234         return (gpe_status & ACPI_EVENT_FLAG_SET) ? true : false;
 235 }
 236
 237 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
 238 {
 239         if (open)
 240                 acpi_enable_gpe(NULL, ec->gpe);
 241         else {
 242                 BUG_ON(ec->reference_count < 1);
 243                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
 244         }
 245         if (acpi_ec_is_gpe_raised(ec)) {
 246                 /*
 247                  * On some platforms, EN=1 writes cannot trigger GPE. So
 248                  * software need to manually trigger a pseudo GPE event on
 249                  * EN=1 writes.
 250                  */
 251                 pr_debug("***** Polling quirk *****\n");
 252                 advance_transaction(ec);
 253         }
 254 }
 255
 256 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
 257 {
 258         if (close)
 259                 acpi_disable_gpe(NULL, ec->gpe);
 260         else {
 261                 BUG_ON(ec->reference_count < 1);
 262                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
 263         }
 264 }
 265
 266 static inline void acpi_ec_clear_gpe(struct acpi_ec *ec)
 267 {
 268         /*
 269          * GPE STS is a W1C register, which means:
 270          * 1. Software can clear it without worrying about clearing other
 271          *    GPEs' STS bits when the hardware sets them in parallel.
 272          * 2. As long as software can ensure only clearing it when it is
 273          *    set, hardware won't set it in parallel.
 274          * So software can clear GPE in any contexts.
 275          * Warning: do not move the check into advance_transaction() as the
 276          * EC commands will be sent without GPE raised.
 277          */
 278         if (!acpi_ec_is_gpe_raised(ec))
 279                 return;
 280         acpi_clear_gpe(NULL, ec->gpe);
 281 }
 282
 283 /* --------------------------------------------------------------------------
 284  *                           Transaction Management
 285  * -------------------------------------------------------------------------- */
 286
 287 static void acpi_ec_submit_request(struct acpi_ec *ec)
 288 {
 289         ec->reference_count++;
 290         if (ec->reference_count == 1)
 291                 acpi_ec_enable_gpe(ec, true);
 292 }
 293
 294 static void acpi_ec_complete_request(struct acpi_ec *ec)
 295 {
 296         bool flushed = false;
 297
 298         ec->reference_count--;
 299         if (ec->reference_count == 0)
 300                 acpi_ec_disable_gpe(ec, true);
 301         flushed = acpi_ec_flushed(ec);
 302         if (flushed)
 303                 wake_up(&ec->wait);
 304 }
 305
 306 static void acpi_ec_set_storm(struct acpi_ec *ec, u8 flag)
 307 {
 308         if (!test_bit(flag, &ec->flags)) {
 309                 acpi_ec_disable_gpe(ec, false);
 310                 pr_debug("+++++ Polling enabled +++++\n");
 311                 set_bit(flag, &ec->flags);
 312         }
 313 }
 314
 315 static void acpi_ec_clear_storm(struct acpi_ec *ec, u8 flag)
 316 {
 317         if (test_bit(flag, &ec->flags)) {
 318                 clear_bit(flag, &ec->flags);
 319                 acpi_ec_enable_gpe(ec, false);
 320                 pr_debug("+++++ Polling disabled +++++\n");
 321         }
 322 }
 323
 324 /*
 325  * acpi_ec_submit_flushable_request() - Increase the reference count unless
 326  *                                      the flush operation is not in
 327  *                                      progress
 328  * @ec: the EC device
 329  * @allow_event: whether event should be handled
 330  *
 331  * This function must be used before taking a new action that should hold
 332  * the reference count.  If this function returns false, then the action
 333  * must be discarded or it will prevent the flush operation from being
 334  * completed.
 335  *
 336  * During flushing, QR_EC command need to pass this check when there is a
 337  * pending event, so that the reference count held for the pending event
 338  * can be decreased by the completion of the QR_EC command.
 339  */
 340 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec,
 341                                              bool allow_event)
 342 {
 343         if (!acpi_ec_started(ec)) {
 344                 if (!allow_event || !acpi_ec_has_pending_event(ec))
 345                         return false;
 346         }
 347         acpi_ec_submit_request(ec);
 348         return true;
 349 }
 350
 351 static void acpi_ec_submit_event(struct acpi_ec *ec)
 352 {
 353         if (!test_bit(EC_FLAGS_EVENT_DETECTED, &ec->flags) ||
 354             !test_bit(EC_FLAGS_EVENT_ENABLED, &ec->flags))
 355                 return;
 356         /* Hold reference for pending event */
 357         if (!acpi_ec_submit_flushable_request(ec, true))
 358                 return;
 359         if (!test_and_set_bit(EC_FLAGS_EVENT_PENDING, &ec->flags)) {
 360                 pr_debug("***** Event query started *****\n");
 361                 schedule_work(&ec->work);
 362                 return;
 363         }
 364         acpi_ec_complete_request(ec);
 365 }
 366
 367 static void acpi_ec_complete_event(struct acpi_ec *ec)
 368 {
 369         if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
 370                 clear_bit(EC_FLAGS_EVENT_PENDING, &ec->flags);
 371                 pr_debug("***** Event query stopped *****\n");
 372                 /* Unhold reference for pending event */
 373                 acpi_ec_complete_request(ec);
 374                 /* Check if there is another SCI_EVT detected */
 375                 acpi_ec_submit_event(ec);
 376         }
 377 }
 378
 379 static void acpi_ec_submit_detection(struct acpi_ec *ec)
 380 {
 381         /* Hold reference for query submission */
 382         if (!acpi_ec_submit_flushable_request(ec, false))
 383                 return;
 384         if (!test_and_set_bit(EC_FLAGS_EVENT_DETECTED, &ec->flags)) {
 385                 pr_debug("***** Event detection blocked *****\n");
 386                 acpi_ec_submit_event(ec);
 387                 return;
 388         }
 389         acpi_ec_complete_request(ec);
 390 }
 391
 392 static void acpi_ec_complete_detection(struct acpi_ec *ec)
 393 {
 394         if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
 395                 clear_bit(EC_FLAGS_EVENT_DETECTED, &ec->flags);
 396                 pr_debug("***** Event detetion unblocked *****\n");
 397                 /* Unhold reference for query submission */
 398                 acpi_ec_complete_request(ec);
 399         }
 400 }
 401
 402 static void acpi_ec_enable_event(struct acpi_ec *ec)
 403 {
 404         unsigned long flags;
 405
 406         spin_lock_irqsave(&ec->lock, flags);
 407         set_bit(EC_FLAGS_EVENT_ENABLED, &ec->flags);
 408         /*
 409          * An event may be pending even with SCI_EVT=0, so QR_EC should
 410          * always be issued right after started.
 411          */
 412         acpi_ec_submit_detection(ec);
 413         spin_unlock_irqrestore(&ec->lock, flags);
 414 }
 415
 416 static int ec_transaction_completed(struct acpi_ec *ec)
 417 {
 418         unsigned long flags;
 419         int ret = 0;
 420
 421         spin_lock_irqsave(&ec->lock, flags);
 422         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
 423                 ret = 1;
 424         spin_unlock_irqrestore(&ec->lock, flags);
 425         return ret;
 426 }
 427
 428 static void advance_transaction(struct acpi_ec *ec)
 429 {
 430         struct transaction *t;
 431         u8 status;
 432         bool wakeup = false;
 433
 434         pr_debug("===== %s (%d) =====\n",
 435                  in_interrupt() ? "IRQ" : "TASK", smp_processor_id());
 436         /*
 437          * By always clearing STS before handling all indications, we can
 438          * ensure a hardware STS 0->1 change after this clearing can always
 439          * trigger a GPE interrupt.
 440          */
 441         acpi_ec_clear_gpe(ec);
 442         status = acpi_ec_read_status(ec);
 443         t = ec->curr;
 444         if (!t)
 445                 goto err;
 446         if (t->flags & ACPI_EC_COMMAND_POLL) {
 447                 if (t->wlen > t->wi) {
 448                         if ((status & ACPI_EC_FLAG_IBF) == 0)
 449                                 acpi_ec_write_data(ec, t->wdata[t->wi++]);
 450                         else
 451                                 goto err;
 452                 } else if (t->rlen > t->ri) {
 453                         if ((status & ACPI_EC_FLAG_OBF) == 1) {
 454                                 t->rdata[t->ri++] = acpi_ec_read_data(ec);
 455                                 if (t->rlen == t->ri) {
 456                                         t->flags |= ACPI_EC_COMMAND_COMPLETE;
 457                                         acpi_ec_complete_event(ec);
 458                                         if (t->command == ACPI_EC_COMMAND_QUERY)
 459                                                 pr_debug("***** Command(%s) hardware completion *****\n",
 460                                                          acpi_ec_cmd_string(t->command));
 461                                         wakeup = true;
 462                                 }
 463                         } else
 464                                 goto err;
 465                 } else if (t->wlen == t->wi &&
 466                            (status & ACPI_EC_FLAG_IBF) == 0) {
 467                         t->flags |= ACPI_EC_COMMAND_COMPLETE;
 468                         acpi_ec_complete_event(ec);
 469                         wakeup = true;
 470                 }
 471                 goto out;
 472         } else {
 473                 if (EC_FLAGS_QUERY_HANDSHAKE &&
 474                     !(status & ACPI_EC_FLAG_SCI) &&
 475                     (t->command == ACPI_EC_COMMAND_QUERY)) {
 476                         t->flags |= ACPI_EC_COMMAND_POLL;
 477                         acpi_ec_complete_detection(ec);
 478                         t->rdata[t->ri++] = 0x00;
 479                         t->flags |= ACPI_EC_COMMAND_COMPLETE;
 480                         acpi_ec_complete_event(ec);
 481                         pr_debug("***** Command(%s) software completion *****\n",
 482                                  acpi_ec_cmd_string(t->command));
 483                         wakeup = true;
 484                 } else if ((status & ACPI_EC_FLAG_IBF) == 0) {
 485                         acpi_ec_write_cmd(ec, t->command);
 486                         t->flags |= ACPI_EC_COMMAND_POLL;
 487                         acpi_ec_complete_detection(ec);
 488                 } else
 489                         goto err;
 490                 goto out;
 491         }
 492 err:
 493         /*
 494          * If SCI bit is set, then don't think it's a false IRQ
 495          * otherwise will take a not handled IRQ as a false one.
 496          */
 497         if (!(status & ACPI_EC_FLAG_SCI)) {
 498                 if (in_interrupt() && t) {
 499                         if (t->irq_count < ec_storm_threshold)
 500                                 ++t->irq_count;
 501                         /* Allow triggering on 0 threshold */
 502                         if (t->irq_count == ec_storm_threshold)
 503                                 acpi_ec_set_storm(ec, EC_FLAGS_COMMAND_STORM);
 504                 }
 505         }
 506 out:
 507         if (status & ACPI_EC_FLAG_SCI)
 508                 acpi_ec_submit_detection(ec);
 509         if (wakeup && in_interrupt())
 510                 wake_up(&ec->wait);
 511 }
 512
 513 static void start_transaction(struct acpi_ec *ec)
 514 {
 515         ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
 516         ec->curr->flags = 0;
 517         ec->curr->timestamp = jiffies;
 518         advance_transaction(ec);
 519 }
 520
 521 static int ec_poll(struct acpi_ec *ec)
 522 {
 523         unsigned long flags;
 524         int repeat = 5; /* number of command restarts */
 525
 526         while (repeat--) {
 527                 unsigned long delay = jiffies +
 528                         msecs_to_jiffies(ec_delay);
 529                 unsigned long usecs = ACPI_EC_UDELAY_POLL;
 530                 do {
 531                         /* don't sleep with disabled interrupts */
 532                         if (EC_FLAGS_MSI || irqs_disabled()) {
 533                                 usecs = ACPI_EC_MSI_UDELAY;
 534                                 udelay(usecs);
 535                                 if (ec_transaction_completed(ec))
 536                                         return 0;
 537                         } else {
 538                                 if (wait_event_timeout(ec->wait,
 539                                                 ec_transaction_completed(ec),
 540                                                 usecs_to_jiffies(usecs)))
 541                                         return 0;
 542                         }
 543                         spin_lock_irqsave(&ec->lock, flags);
 544                         if (time_after(jiffies,
 545                                         ec->curr->timestamp +
 546                                         usecs_to_jiffies(usecs)))
 547                                 advance_transaction(ec);
 548                         spin_unlock_irqrestore(&ec->lock, flags);
 549                 } while (time_before(jiffies, delay));
 550                 pr_debug("controller reset, restart transaction\n");
 551                 spin_lock_irqsave(&ec->lock, flags);
 552                 start_transaction(ec);
 553                 spin_unlock_irqrestore(&ec->lock, flags);
 554         }
 555         return -ETIME;
 556 }
 557
 558 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
 559                                         struct transaction *t)
 560 {
 561         unsigned long tmp;
 562         int ret = 0;
 563
 564         if (EC_FLAGS_MSI)
 565                 udelay(ACPI_EC_MSI_UDELAY);
 566         /* start transaction */
 567         spin_lock_irqsave(&ec->lock, tmp);
 568         /* Enable GPE for command processing (IBF=0/OBF=1) */
 569         if (!acpi_ec_submit_flushable_request(ec, true)) {
 570                 ret = -EINVAL;
 571                 goto unlock;
 572         }
 573         /* following two actions should be kept atomic */
 574         ec->curr = t;
 575         pr_debug("***** Command(%s) started *****\n",
 576                  acpi_ec_cmd_string(t->command));
 577         start_transaction(ec);
 578         spin_unlock_irqrestore(&ec->lock, tmp);
 579         ret = ec_poll(ec);
 580         spin_lock_irqsave(&ec->lock, tmp);
 581         if (t->irq_count == ec_storm_threshold)
 582                 acpi_ec_clear_storm(ec, EC_FLAGS_COMMAND_STORM);
 583         pr_debug("***** Command(%s) stopped *****\n",
 584                  acpi_ec_cmd_string(t->command));
 585         ec->curr = NULL;
 586         /* Disable GPE for command processing (IBF=0/OBF=1) */
 587         acpi_ec_complete_request(ec);
 588 unlock:
 589         spin_unlock_irqrestore(&ec->lock, tmp);
 590         return ret;
 591 }
 592
 593 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
 594 {
 595         int status;
 596         u32 glk;
 597
 598         if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
 599                 return -EINVAL;
 600         if (t->rdata)
 601                 memset(t->rdata, 0, t->rlen);
 602         mutex_lock(&ec->mutex);
 603         if (ec->global_lock) {
 604                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
 605                 if (ACPI_FAILURE(status)) {
 606                         status = -ENODEV;
 607                         goto unlock;
 608                 }
 609         }
 610
 611         status = acpi_ec_transaction_unlocked(ec, t);
 612
 613         if (test_bit(EC_FLAGS_COMMAND_STORM, &ec->flags))
 614                 msleep(1);
 615         if (ec->global_lock)
 616                 acpi_release_global_lock(glk);
 617 unlock:
 618         mutex_unlock(&ec->mutex);
 619         return status;
 620 }
 621
 622 static int acpi_ec_burst_enable(struct acpi_ec *ec)
 623 {
 624         u8 d;
 625         struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
 626                                 .wdata = NULL, .rdata = &d,
 627                                 .wlen = 0, .rlen = 1};
 628
 629         return acpi_ec_transaction(ec, &t);
 630 }
 631
 632 static int acpi_ec_burst_disable(struct acpi_ec *ec)
 633 {
 634         struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
 635                                 .wdata = NULL, .rdata = NULL,
 636                                 .wlen = 0, .rlen = 0};
 637
 638         return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
 639                                 acpi_ec_transaction(ec, &t) : 0;
 640 }
 641
 642 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
 643 {
 644         int result;
 645         u8 d;
 646         struct transaction t = {.command = ACPI_EC_COMMAND_READ,
 647                                 .wdata = &address, .rdata = &d,
 648                                 .wlen = 1, .rlen = 1};
 649
 650         result = acpi_ec_transaction(ec, &t);
 651         *data = d;
 652         return result;
 653 }
 654
 655 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
 656 {
 657         u8 wdata[2] = { address, data };
 658         struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
 659                                 .wdata = wdata, .rdata = NULL,
 660                                 .wlen = 2, .rlen = 0};
 661
 662         return acpi_ec_transaction(ec, &t);
 663 }
 664
 665 int ec_read(u8 addr, u8 *val)
 666 {
 667         int err;
 668         u8 temp_data;
 669
 670         if (!first_ec)
 671                 return -ENODEV;
 672
 673         err = acpi_ec_read(first_ec, addr, &temp_data);
 674
 675         if (!err) {
 676                 *val = temp_data;
 677                 return 0;
 678         }
 679         return err;
 680 }
 681 EXPORT_SYMBOL(ec_read);
 682
 683 int ec_write(u8 addr, u8 val)
 684 {
 685         int err;
 686
 687         if (!first_ec)
 688                 return -ENODEV;
 689
 690         err = acpi_ec_write(first_ec, addr, val);
 691
 692         return err;
 693 }
 694 EXPORT_SYMBOL(ec_write);
 695
 696 int ec_transaction(u8 command,
 697                    const u8 *wdata, unsigned wdata_len,
 698                    u8 *rdata, unsigned rdata_len)
 699 {
 700         struct transaction t = {.command = command,
 701                                 .wdata = wdata, .rdata = rdata,
 702                                 .wlen = wdata_len, .rlen = rdata_len};
 703
 704         if (!first_ec)
 705                 return -ENODEV;
 706
 707         return acpi_ec_transaction(first_ec, &t);
 708 }
 709 EXPORT_SYMBOL(ec_transaction);
 710
 711 /* Get the handle to the EC device */
 712 acpi_handle ec_get_handle(void)
 713 {
 714         if (!first_ec)
 715                 return NULL;
 716         return first_ec->handle;
 717 }
 718 EXPORT_SYMBOL(ec_get_handle);
 719
 720 /*
 721  * Process _Q events that might have accumulated in the EC.
 722  * Run with locked ec mutex.
 723  */
 724 static void acpi_ec_clear(struct acpi_ec *ec)
 725 {
 726         int i, status;
 727         u8 value = 0;
 728
 729         for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
 730                 status = acpi_ec_query(ec, &value);
 731                 if (status || !value)
 732                         break;
 733         }
 734
 735         if (unlikely(i == ACPI_EC_CLEAR_MAX))
 736                 pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
 737         else
 738                 pr_info("%d stale EC events cleared\n", i);
 739 }
 740
 741 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
 742 {
 743         unsigned long flags;
 744
 745         spin_lock_irqsave(&ec->lock, flags);
 746         if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
 747                 pr_debug("+++++ Starting EC +++++\n");
 748                 /* Enable GPE for event processing (SCI_EVT=1) */
 749                 if (!resuming)
 750                         acpi_ec_submit_request(ec);
 751                 pr_info("+++++ EC started +++++\n");
 752         }
 753         spin_unlock_irqrestore(&ec->lock, flags);
 754 }
 755
 756 static bool acpi_ec_stopped(struct acpi_ec *ec)
 757 {
 758         unsigned long flags;
 759         bool flushed;
 760
 761         spin_lock_irqsave(&ec->lock, flags);
 762         flushed = acpi_ec_flushed(ec);
 763         spin_unlock_irqrestore(&ec->lock, flags);
 764         return flushed;
 765 }
 766
 767 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
 768 {
 769         unsigned long flags;
 770
 771         spin_lock_irqsave(&ec->lock, flags);
 772         if (acpi_ec_started(ec)) {
 773                 pr_debug("+++++ Stopping EC +++++\n");
 774                 set_bit(EC_FLAGS_STOPPED, &ec->flags);
 775                 spin_unlock_irqrestore(&ec->lock, flags);
 776                 wait_event(ec->wait, acpi_ec_stopped(ec));
 777                 spin_lock_irqsave(&ec->lock, flags);
 778                 /* Disable GPE for event processing (SCI_EVT=1) */
 779                 if (!suspending)
 780                         acpi_ec_complete_request(ec);
 781                 clear_bit(EC_FLAGS_STARTED, &ec->flags);
 782                 clear_bit(EC_FLAGS_STOPPED, &ec->flags);
 783                 pr_info("+++++ EC stopped +++++\n");
 784         }
 785         spin_unlock_irqrestore(&ec->lock, flags);
 786 }
 787
 788 void acpi_ec_block_transactions(void)
 789 {
 790         struct acpi_ec *ec = first_ec;
 791
 792         if (!ec)
 793                 return;
 794
 795         mutex_lock(&ec->mutex);
 796         /* Prevent transactions from being carried out */
 797         acpi_ec_stop(ec, true);
 798         mutex_unlock(&ec->mutex);
 799 }
 800
 801 void acpi_ec_unblock_transactions(void)
 802 {
 803         struct acpi_ec *ec = first_ec;
 804
 805         if (!ec)
 806                 return;
 807
 808         /* Allow transactions to be carried out again */
 809         acpi_ec_start(ec, true);
 810
 811         if (EC_FLAGS_CLEAR_ON_RESUME)
 812                 acpi_ec_clear(ec);
 813 }
 814
 815 void acpi_ec_unblock_transactions_early(void)
 816 {
 817         /*
 818          * Allow transactions to happen again (this function is called from
 819          * atomic context during wakeup, so we don't need to acquire the mutex).
 820          */
 821         if (first_ec)
 822                 acpi_ec_start(first_ec, true);
 823 }
 824
 825 /* --------------------------------------------------------------------------
 826                                 Event Management
 827    -------------------------------------------------------------------------- */
 828 static struct acpi_ec_query_handler *
 829 acpi_ec_get_query_handler(struct acpi_ec_query_handler *handler)
 830 {
 831         if (handler)
 832                 kref_get(&handler->kref);
 833         return handler;
 834 }
 835
 836 static void acpi_ec_query_handler_release(struct kref *kref)
 837 {
 838         struct acpi_ec_query_handler *handler =
 839                 container_of(kref, struct acpi_ec_query_handler, kref);
 840
 841         kfree(handler);
 842 }
 843
 844 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
 845 {
 846         kref_put(&handler->kref, acpi_ec_query_handler_release);
 847 }
 848
 849 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
 850                               acpi_handle handle, acpi_ec_query_func func,
 851                               void *data)
 852 {
 853         struct acpi_ec_query_handler *handler =
 854             kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
 855
 856         if (!handler)
 857                 return -ENOMEM;
 858
 859         handler->query_bit = query_bit;
 860         handler->handle = handle;
 861         handler->func = func;
 862         handler->data = data;
 863         mutex_lock(&ec->mutex);
 864         kref_init(&handler->kref);
 865         list_add(&handler->node, &ec->list);
 866         mutex_unlock(&ec->mutex);
 867         return 0;
 868 }
 869 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
 870
 871 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
 872 {
 873         struct acpi_ec_query_handler *handler, *tmp;
 874         LIST_HEAD(free_list);
 875
 876         mutex_lock(&ec->mutex);
 877         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
 878                 if (query_bit == handler->query_bit) {
 879                         list_del_init(&handler->node);
 880                         list_add(&handler->node, &free_list);
 881                 }
 882         }
 883         mutex_unlock(&ec->mutex);
 884         list_for_each_entry(handler, &free_list, node)
 885                 acpi_ec_put_query_handler(handler);
 886 }
 887 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
 888
 889 static void acpi_ec_run(void *cxt)
 890 {
 891         struct acpi_ec_query_handler *handler = cxt;
 892
 893         if (!handler)
 894                 return;
 895         pr_debug("##### Query(0x%02x) started #####\n", handler->query_bit);
 896         if (handler->func)
 897                 handler->func(handler->data);
 898         else if (handler->handle)
 899                 acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
 900         pr_debug("##### Query(0x%02x) stopped #####\n", handler->query_bit);
 901         acpi_ec_put_query_handler(handler);
 902 }
 903
 904 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
 905 {
 906         u8 value = 0;
 907         int result;
 908         acpi_status status;
 909         struct acpi_ec_query_handler *handler;
 910         struct transaction t = {.command = ACPI_EC_COMMAND_QUERY,
 911                                 .wdata = NULL, .rdata = &value,
 912                                 .wlen = 0, .rlen = 1};
 913
 914         /*
 915          * Query the EC to find out which _Qxx method we need to evaluate.
 916          * Note that successful completion of the query causes the ACPI_EC_SCI
 917          * bit to be cleared (and thus clearing the interrupt source).
 918          */
 919         result = acpi_ec_transaction(ec, &t);
 920         if (result)
 921                 return result;
 922         if (data)
 923                 *data = value;
 924         if (!value)
 925                 return -ENODATA;
 926
 927         mutex_lock(&ec->mutex);
 928         list_for_each_entry(handler, &ec->list, node) {
 929                 if (value == handler->query_bit) {
 930                         /* have custom handler for this bit */
 931                         handler = acpi_ec_get_query_handler(handler);
 932                         pr_debug("##### Query(0x%02x) scheduled #####\n",
 933                                  handler->query_bit);
 934                         status = acpi_os_execute((handler->func) ?
 935                                 OSL_NOTIFY_HANDLER : OSL_GPE_HANDLER,
 936                                 acpi_ec_run, handler);
 937                         if (ACPI_FAILURE(status))
 938                                 result = -EBUSY;
 939                         break;
 940                 }
 941         }
 942         mutex_unlock(&ec->mutex);
 943         return result;
 944 }
 945
 946 static void acpi_ec_gpe_poller(struct work_struct *work)
 947 {
 948         struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
 949
 950         pr_debug("***** Event poller started *****\n");
 951         acpi_ec_query(ec, NULL);
 952         pr_debug("***** Event poller stopped *****\n");
 953 }
 954
 955 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
 956         u32 gpe_number, void *data)
 957 {
 958         unsigned long flags;
 959         struct acpi_ec *ec = data;
 960
 961         spin_lock_irqsave(&ec->lock, flags);
 962         advance_transaction(ec);
 963         spin_unlock_irqrestore(&ec->lock, flags);
 964         return ACPI_INTERRUPT_HANDLED;
 965 }
 966
 967 /* --------------------------------------------------------------------------
 968  *                           Address Space Management
 969  * -------------------------------------------------------------------------- */
 970
 971 static acpi_status
 972 acpi_ec_space_handler(u32 function, acpi_physical_address address,
 973                       u32 bits, u64 *value64,
 974                       void *handler_context, void *region_context)
 975 {
 976         struct acpi_ec *ec = handler_context;
 977         int result = 0, i, bytes = bits / 8;
 978         u8 *value = (u8 *)value64;
 979
 980         if ((address > 0xFF) || !value || !handler_context)
 981                 return AE_BAD_PARAMETER;
 982
 983         if (function != ACPI_READ && function != ACPI_WRITE)
 984                 return AE_BAD_PARAMETER;
 985
 986         if (EC_FLAGS_MSI || bits > 8)
 987                 acpi_ec_burst_enable(ec);
 988
 989         for (i = 0; i < bytes; ++i, ++address, ++value)
 990                 result = (function == ACPI_READ) ?
 991                         acpi_ec_read(ec, address, value) :
 992                         acpi_ec_write(ec, address, *value);
 993
 994         if (EC_FLAGS_MSI || bits > 8)
 995                 acpi_ec_burst_disable(ec);
 996
 997         switch (result) {
 998         case -EINVAL:
 999                 return AE_BAD_PARAMETER;
1000         case -ENODEV:
1001                 return AE_NOT_FOUND;
1002         case -ETIME:
1003                 return AE_TIME;
1004         default:
1005                 return AE_OK;
1006         }
1007 }
1008
1009 /* --------------------------------------------------------------------------
1010  *                             Driver Interface
1011  * -------------------------------------------------------------------------- */
1012
1013 static acpi_status
1014 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1015
1016 static struct acpi_ec *make_acpi_ec(void)
1017 {
1018         struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1019
1020         if (!ec)
1021                 return NULL;
1022         mutex_init(&ec->mutex);
1023         init_waitqueue_head(&ec->wait);
1024         INIT_LIST_HEAD(&ec->list);
1025         spin_lock_init(&ec->lock);
1026         INIT_WORK(&ec->work, acpi_ec_gpe_poller);
1027         return ec;
1028 }
1029
1030 static acpi_status
1031 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1032                                void *context, void **return_value)
1033 {
1034         char node_name[5];
1035         struct acpi_buffer buffer = { sizeof(node_name), node_name };
1036         struct acpi_ec *ec = context;
1037         int value = 0;
1038         acpi_status status;
1039
1040         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1041
1042         if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1043                 acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1044         return AE_OK;
1045 }
1046
1047 static acpi_status
1048 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1049 {
1050         acpi_status status;
1051         unsigned long long tmp = 0;
1052         struct acpi_ec *ec = context;
1053
1054         /* clear addr values, ec_parse_io_ports depend on it */
1055         ec->command_addr = ec->data_addr = 0;
1056
1057         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1058                                      ec_parse_io_ports, ec);
1059         if (ACPI_FAILURE(status))
1060                 return status;
1061
1062         /* Get GPE bit assignment (EC events). */
1063         /* TODO: Add support for _GPE returning a package */
1064         status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1065         if (ACPI_FAILURE(status))
1066                 return status;
1067         ec->gpe = tmp;
1068         /* Use the global lock for all EC transactions? */
1069         tmp = 0;
1070         acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1071         ec->global_lock = tmp;
1072         ec->handle = handle;
1073         return AE_CTRL_TERMINATE;
1074 }
1075
1076 static int ec_install_handlers(struct acpi_ec *ec)
1077 {
1078         acpi_status status;
1079
1080         if (test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
1081                 return 0;
1082         status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1083                                   ACPI_GPE_EDGE_TRIGGERED,
1084                                   &acpi_ec_gpe_handler, ec);
1085         if (ACPI_FAILURE(status))
1086                 return -ENODEV;
1087
1088         acpi_ec_start(ec, false);
1089         status = acpi_install_address_space_handler(ec->handle,
1090                                                     ACPI_ADR_SPACE_EC,
1091                                                     &acpi_ec_space_handler,
1092                                                     NULL, ec);
1093         if (ACPI_FAILURE(status)) {
1094                 if (status == AE_NOT_FOUND) {
1095                         /*
1096                          * Maybe OS fails in evaluating the _REG object.
1097                          * The AE_NOT_FOUND error will be ignored and OS
1098                          * continue to initialize EC.
1099                          */
1100                         pr_err("Fail in evaluating the _REG object"
1101                                 " of EC device. Broken bios is suspected.\n");
1102                 } else {
1103                         acpi_ec_stop(ec, false);
1104                         acpi_remove_gpe_handler(NULL, ec->gpe,
1105                                 &acpi_ec_gpe_handler);
1106                         return -ENODEV;
1107                 }
1108         }
1109
1110         set_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
1111         return 0;
1112 }
1113
1114 static void ec_remove_handlers(struct acpi_ec *ec)
1115 {
1116         if (!test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
1117                 return;
1118         acpi_ec_stop(ec, false);
1119         if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1120                                 ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1121                 pr_err("failed to remove space handler\n");
1122         if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1123                                 &acpi_ec_gpe_handler)))
1124                 pr_err("failed to remove gpe handler\n");
1125         clear_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
1126 }
1127
1128 static int acpi_ec_add(struct acpi_device *device)
1129 {
1130         struct acpi_ec *ec = NULL;
1131         int ret;
1132
1133         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1134         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1135
1136         /* Check for boot EC */
1137         if (boot_ec &&
1138             (boot_ec->handle == device->handle ||
1139              boot_ec->handle == ACPI_ROOT_OBJECT)) {
1140                 ec = boot_ec;
1141                 boot_ec = NULL;
1142         } else {
1143                 ec = make_acpi_ec();
1144                 if (!ec)
1145                         return -ENOMEM;
1146         }
1147         if (ec_parse_device(device->handle, 0, ec, NULL) !=
1148                 AE_CTRL_TERMINATE) {
1149                         kfree(ec);
1150                         return -EINVAL;
1151         }
1152
1153         /* Find and register all query methods */
1154         acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1155                             acpi_ec_register_query_methods, NULL, ec, NULL);
1156
1157         if (!first_ec)
1158                 first_ec = ec;
1159         device->driver_data = ec;
1160
1161         ret = !!request_region(ec->data_addr, 1, "EC data");
1162         WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1163         ret = !!request_region(ec->command_addr, 1, "EC cmd");
1164         WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1165
1166         pr_info("GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
1167                           ec->gpe, ec->command_addr, ec->data_addr);
1168
1169         ret = ec_install_handlers(ec);
1170
1171         /* EC is fully operational, allow queries */
1172         acpi_ec_enable_event(ec);
1173
1174         /* Clear stale _Q events if hardware might require that */
1175         if (EC_FLAGS_CLEAR_ON_RESUME)
1176                 acpi_ec_clear(ec);
1177         return ret;
1178 }
1179
1180 static int acpi_ec_remove(struct acpi_device *device)
1181 {
1182         struct acpi_ec *ec;
1183         struct acpi_ec_query_handler *handler, *tmp;
1184
1185         if (!device)
1186                 return -EINVAL;
1187
1188         ec = acpi_driver_data(device);
1189         ec_remove_handlers(ec);
1190         mutex_lock(&ec->mutex);
1191         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1192                 list_del(&handler->node);
1193                 kfree(handler);
1194         }
1195         mutex_unlock(&ec->mutex);
1196         release_region(ec->data_addr, 1);
1197         release_region(ec->command_addr, 1);
1198         device->driver_data = NULL;
1199         if (ec == first_ec)
1200                 first_ec = NULL;
1201         kfree(ec);
1202         return 0;
1203 }
1204
1205 static acpi_status
1206 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1207 {
1208         struct acpi_ec *ec = context;
1209
1210         if (resource->type != ACPI_RESOURCE_TYPE_IO)
1211                 return AE_OK;
1212
1213         /*
1214          * The first address region returned is the data port, and
1215          * the second address region returned is the status/command
1216          * port.
1217          */
1218         if (ec->data_addr == 0)
1219                 ec->data_addr = resource->data.io.minimum;
1220         else if (ec->command_addr == 0)
1221                 ec->command_addr = resource->data.io.minimum;
1222         else
1223                 return AE_CTRL_TERMINATE;
1224
1225         return AE_OK;
1226 }
1227
1228 int __init acpi_boot_ec_enable(void)
1229 {
1230         if (!boot_ec || test_bit(EC_FLAGS_HANDLERS_INSTALLED, &boot_ec->flags))
1231                 return 0;
1232         if (!ec_install_handlers(boot_ec)) {
1233                 first_ec = boot_ec;
1234                 return 0;
1235         }
1236         return -EFAULT;
1237 }
1238
1239 static const struct acpi_device_id ec_device_ids[] = {
1240         {"PNP0C09", 0},
1241         {"", 0},
1242 };
1243
1244 /* Some BIOS do not survive early DSDT scan, skip it */
1245 static int ec_skip_dsdt_scan(const struct dmi_system_id *id)
1246 {
1247         EC_FLAGS_SKIP_DSDT_SCAN = 1;
1248         return 0;
1249 }
1250
1251 /* ASUStek often supplies us with broken ECDT, validate it */
1252 static int ec_validate_ecdt(const struct dmi_system_id *id)
1253 {
1254         EC_FLAGS_VALIDATE_ECDT = 1;
1255         return 0;
1256 }
1257
1258 /* MSI EC needs special treatment, enable it */
1259 static int ec_flag_msi(const struct dmi_system_id *id)
1260 {
1261         pr_debug("Detected MSI hardware, enabling workarounds.\n");
1262         EC_FLAGS_MSI = 1;
1263         EC_FLAGS_VALIDATE_ECDT = 1;
1264         return 0;
1265 }
1266
1267 /*
1268  * Clevo M720 notebook actually works ok with IRQ mode, if we lifted
1269  * the GPE storm threshold back to 20
1270  */
1271 static int ec_enlarge_storm_threshold(const struct dmi_system_id *id)
1272 {
1273         pr_debug("Setting the EC GPE storm threshold to 20\n");
1274         ec_storm_threshold  = 20;
1275         return 0;
1276 }
1277
1278 /*
1279  * Acer EC firmware refuses to respond QR_EC when SCI_EVT is not set, for
1280  * which case, we complete the QR_EC without issuing it to the firmware.
1281  * https://bugzilla.kernel.org/show_bug.cgi?id=86211
1282  */
1283 static int ec_flag_query_handshake(const struct dmi_system_id *id)
1284 {
1285         pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
1286         EC_FLAGS_QUERY_HANDSHAKE = 1;
1287         return 0;
1288 }
1289
1290 /*
1291  * On some hardware it is necessary to clear events accumulated by the EC during
1292  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1293  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1294  *
1295  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1296  *
1297  * Ideally, the EC should also be instructed NOT to accumulate events during
1298  * sleep (which Windows seems to do somehow), but the interface to control this
1299  * behaviour is not known at this time.
1300  *
1301  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1302  * however it is very likely that other Samsung models are affected.
1303  *
1304  * On systems which don't accumulate _Q events during sleep, this extra check
1305  * should be harmless.
1306  */
1307 static int ec_clear_on_resume(const struct dmi_system_id *id)
1308 {
1309         pr_debug("Detected system needing EC poll on resume.\n");
1310         EC_FLAGS_CLEAR_ON_RESUME = 1;
1311         return 0;
1312 }
1313
1314 static struct dmi_system_id ec_dmi_table[] __initdata = {
1315         {
1316         ec_skip_dsdt_scan, "Compal JFL92", {
1317         DMI_MATCH(DMI_BIOS_VENDOR, "COMPAL"),
1318         DMI_MATCH(DMI_BOARD_NAME, "JFL92") }, NULL},
1319         {
1320         ec_flag_msi, "MSI hardware", {
1321         DMI_MATCH(DMI_BIOS_VENDOR, "Micro-Star")}, NULL},
1322         {
1323         ec_flag_msi, "MSI hardware", {
1324         DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star")}, NULL},
1325         {
1326         ec_flag_msi, "MSI hardware", {
1327         DMI_MATCH(DMI_CHASSIS_VENDOR, "MICRO-Star")}, NULL},
1328         {
1329         ec_flag_msi, "MSI hardware", {
1330         DMI_MATCH(DMI_CHASSIS_VENDOR, "MICRO-STAR")}, NULL},
1331         {
1332         ec_flag_msi, "Quanta hardware", {
1333         DMI_MATCH(DMI_SYS_VENDOR, "Quanta"),
1334         DMI_MATCH(DMI_PRODUCT_NAME, "TW8/SW8/DW8"),}, NULL},
1335         {
1336         ec_flag_msi, "Quanta hardware", {
1337         DMI_MATCH(DMI_SYS_VENDOR, "Quanta"),
1338         DMI_MATCH(DMI_PRODUCT_NAME, "TW9/SW9"),}, NULL},
1339         {
1340         ec_flag_msi, "Clevo W350etq", {
1341         DMI_MATCH(DMI_SYS_VENDOR, "CLEVO CO."),
1342         DMI_MATCH(DMI_PRODUCT_NAME, "W35_37ET"),}, NULL},
1343         {
1344         ec_validate_ecdt, "ASUS hardware", {
1345         DMI_MATCH(DMI_BIOS_VENDOR, "ASUS") }, NULL},
1346         {
1347         ec_validate_ecdt, "ASUS hardware", {
1348         DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer Inc.") }, NULL},
1349         {
1350         ec_enlarge_storm_threshold, "CLEVO hardware", {
1351         DMI_MATCH(DMI_SYS_VENDOR, "CLEVO Co."),
1352         DMI_MATCH(DMI_PRODUCT_NAME, "M720T/M730T"),}, NULL},
1353         {
1354         ec_skip_dsdt_scan, "HP Folio 13", {
1355         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
1356         DMI_MATCH(DMI_PRODUCT_NAME, "HP Folio 13"),}, NULL},
1357         {
1358         ec_validate_ecdt, "ASUS hardware", {
1359         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTek Computer Inc."),
1360         DMI_MATCH(DMI_PRODUCT_NAME, "L4R"),}, NULL},
1361         {
1362         ec_clear_on_resume, "Samsung hardware", {
1363         DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1364         {
1365         ec_flag_query_handshake, "Acer hardware", {
1366         DMI_MATCH(DMI_SYS_VENDOR, "Acer"), }, NULL},
1367         {},
1368 };
1369
1370 int __init acpi_ec_ecdt_probe(void)
1371 {
1372         acpi_status status;
1373         struct acpi_ec *saved_ec = NULL;
1374         struct acpi_table_ecdt *ecdt_ptr;
1375
1376         boot_ec = make_acpi_ec();
1377         if (!boot_ec)
1378                 return -ENOMEM;
1379         /*
1380          * Generate a boot ec context
1381          */
1382         dmi_check_system(ec_dmi_table);
1383         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1384                                 (struct acpi_table_header **)&ecdt_ptr);
1385         if (ACPI_SUCCESS(status)) {
1386                 pr_info("EC description table is found, configuring boot EC\n");
1387                 boot_ec->command_addr = ecdt_ptr->control.address;
1388                 boot_ec->data_addr = ecdt_ptr->data.address;
1389                 boot_ec->gpe = ecdt_ptr->gpe;
1390                 boot_ec->handle = ACPI_ROOT_OBJECT;
1391                 acpi_get_handle(ACPI_ROOT_OBJECT, ecdt_ptr->id,
1392                                 &boot_ec->handle);
1393                 /* Don't trust ECDT, which comes from ASUSTek */
1394                 if (!EC_FLAGS_VALIDATE_ECDT)
1395                         goto install;
1396                 saved_ec = kmemdup(boot_ec, sizeof(struct acpi_ec), GFP_KERNEL);
1397                 if (!saved_ec)
1398                         return -ENOMEM;
1399         /* fall through */
1400         }
1401
1402         if (EC_FLAGS_SKIP_DSDT_SCAN) {
1403                 kfree(saved_ec);
1404                 return -ENODEV;
1405         }
1406
1407         /* This workaround is needed only on some broken machines,
1408          * which require early EC, but fail to provide ECDT */
1409         pr_debug("Look up EC in DSDT\n");
1410         status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device,
1411                                         boot_ec, NULL);
1412         /* Check that acpi_get_devices actually find something */
1413         if (ACPI_FAILURE(status) || !boot_ec->handle)
1414                 goto error;
1415         if (saved_ec) {
1416                 /* try to find good ECDT from ASUSTek */
1417                 if (saved_ec->command_addr != boot_ec->command_addr ||
1418                     saved_ec->data_addr != boot_ec->data_addr ||
1419                     saved_ec->gpe != boot_ec->gpe ||
1420                     saved_ec->handle != boot_ec->handle)
1421                         pr_info("ASUSTek keeps feeding us with broken "
1422                         "ECDT tables, which are very hard to workaround. "
1423                         "Trying to use DSDT EC info instead. Please send "
1424                         "output of acpidump to linux-acpi@vger.kernel.org\n");
1425                 kfree(saved_ec);
1426                 saved_ec = NULL;
1427         } else {
1428                 /* We really need to limit this workaround, the only ASUS,
1429                 * which needs it, has fake EC._INI method, so use it as flag.
1430                 * Keep boot_ec struct as it will be needed soon.
1431                 */
1432                 if (!dmi_name_in_vendors("ASUS") ||
1433                     !acpi_has_method(boot_ec->handle, "_INI"))
1434                         return -ENODEV;
1435         }
1436 install:
1437         if (!ec_install_handlers(boot_ec)) {
1438                 first_ec = boot_ec;
1439                 return 0;
1440         }
1441 error:
1442         kfree(boot_ec);
1443         kfree(saved_ec);
1444         boot_ec = NULL;
1445         return -ENODEV;
1446 }
1447
1448 static struct acpi_driver acpi_ec_driver = {
1449         .name = "ec",
1450         .class = ACPI_EC_CLASS,
1451         .ids = ec_device_ids,
1452         .ops = {
1453                 .add = acpi_ec_add,
1454                 .remove = acpi_ec_remove,
1455                 },
1456 };
1457
1458 int __init acpi_ec_init(void)
1459 {
1460         int result = 0;
1461
1462         /* Now register the driver for the EC */
1463         result = acpi_bus_register_driver(&acpi_ec_driver);
1464         if (result < 0)
1465                 return -ENODEV;
1466
1467         return result;
1468 }
1469
1470 /* EC driver currently not unloadable */
1471 #if 0
1472 static void __exit acpi_ec_exit(void)
1473 {
1474
1475         acpi_bus_unregister_driver(&acpi_ec_driver);
1476 }
1477 #endif  /* 0 */