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  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  26  */
  27
  28 /* Uncomment next line to get verbose printout */
  29 /* #define DEBUG */
  30 #define pr_fmt(fmt) "ACPI : EC: " fmt
  31
  32 #include <linux/kernel.h>
  33 #include <linux/module.h>
  34 #include <linux/init.h>
  35 #include <linux/types.h>
  36 #include <linux/delay.h>
  37 #include <linux/interrupt.h>
  38 #include <linux/list.h>
  39 #include <linux/spinlock.h>
  40 #include <linux/slab.h>
  41 #include <linux/acpi.h>
  42 #include <linux/dmi.h>
  43 #include <asm/io.h>
  44
  45 #include "internal.h"
  46
  47 #define ACPI_EC_CLASS                   "embedded_controller"
  48 #define ACPI_EC_DEVICE_NAME             "Embedded Controller"
  49 #define ACPI_EC_FILE_INFO               "info"
  50
  51 /* EC status register */
  52 #define ACPI_EC_FLAG_OBF        0x01    /* Output buffer full */
  53 #define ACPI_EC_FLAG_IBF        0x02    /* Input buffer full */
  54 #define ACPI_EC_FLAG_CMD        0x08    /* Input buffer contains a command */
  55 #define ACPI_EC_FLAG_BURST      0x10    /* burst mode */
  56 #define ACPI_EC_FLAG_SCI        0x20    /* EC-SCI occurred */
  57
  58 /*
  59  * The SCI_EVT clearing timing is not defined by the ACPI specification.
  60  * This leads to lots of practical timing issues for the host EC driver.
  61  * The following variations are defined (from the target EC firmware's
  62  * perspective):
  63  * STATUS: After indicating SCI_EVT edge triggered IRQ to the host, the
  64  *         target can clear SCI_EVT at any time so long as the host can see
  65  *         the indication by reading the status register (EC_SC). So the
  66  *         host should re-check SCI_EVT after the first time the SCI_EVT
  67  *         indication is seen, which is the same time the query request
  68  *         (QR_EC) is written to the command register (EC_CMD). SCI_EVT set
  69  *         at any later time could indicate another event. Normally such
  70  *         kind of EC firmware has implemented an event queue and will
  71  *         return 0x00 to indicate "no outstanding event".
  72  * QUERY: After seeing the query request (QR_EC) written to the command
  73  *        register (EC_CMD) by the host and having prepared the responding
  74  *        event value in the data register (EC_DATA), the target can safely
  75  *        clear SCI_EVT because the target can confirm that the current
  76  *        event is being handled by the host. The host then should check
  77  *        SCI_EVT right after reading the event response from the data
  78  *        register (EC_DATA).
  79  * EVENT: After seeing the event response read from the data register
  80  *        (EC_DATA) by the host, the target can clear SCI_EVT. As the
  81  *        target requires time to notice the change in the data register
  82  *        (EC_DATA), the host may be required to wait additional guarding
  83  *        time before checking the SCI_EVT again. Such guarding may not be
  84  *        necessary if the host is notified via another IRQ.
  85  */
  86 #define ACPI_EC_EVT_TIMING_STATUS       0x00
  87 #define ACPI_EC_EVT_TIMING_QUERY        0x01
  88 #define ACPI_EC_EVT_TIMING_EVENT        0x02
  89
  90 /* EC commands */
  91 enum ec_command {
  92         ACPI_EC_COMMAND_READ = 0x80,
  93         ACPI_EC_COMMAND_WRITE = 0x81,
  94         ACPI_EC_BURST_ENABLE = 0x82,
  95         ACPI_EC_BURST_DISABLE = 0x83,
  96         ACPI_EC_COMMAND_QUERY = 0x84,
  97 };
  98
  99 #define ACPI_EC_DELAY           500     /* Wait 500ms max. during EC ops */
 100 #define ACPI_EC_UDELAY_GLK      1000    /* Wait 1ms max. to get global lock */
 101 #define ACPI_EC_UDELAY_POLL     550     /* Wait 1ms for EC transaction polling */
 102 #define ACPI_EC_CLEAR_MAX       100     /* Maximum number of events to query
 103                                          * when trying to clear the EC */
 104 #define ACPI_EC_MAX_QUERIES     16      /* Maximum number of parallel queries */
 105
 106 enum {
 107         EC_FLAGS_QUERY_ENABLED,         /* Query is enabled */
 108         EC_FLAGS_QUERY_PENDING,         /* Query is pending */
 109         EC_FLAGS_QUERY_GUARDING,        /* Guard for SCI_EVT check */
 110         EC_FLAGS_GPE_HANDLER_INSTALLED, /* GPE handler installed */
 111         EC_FLAGS_EC_HANDLER_INSTALLED,  /* OpReg handler installed */
 112         EC_FLAGS_EVT_HANDLER_INSTALLED, /* _Qxx handlers installed */
 113         EC_FLAGS_STARTED,               /* Driver is started */
 114         EC_FLAGS_STOPPED,               /* Driver is stopped */
 115         EC_FLAGS_COMMAND_STORM,         /* GPE storms occurred to the
 116                                          * current command processing */
 117 };
 118
 119 #define ACPI_EC_COMMAND_POLL            0x01 /* Available for command byte */
 120 #define ACPI_EC_COMMAND_COMPLETE        0x02 /* Completed last byte */
 121
 122 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
 123 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
 124 module_param(ec_delay, uint, 0644);
 125 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
 126
 127 static unsigned int ec_max_queries __read_mostly = ACPI_EC_MAX_QUERIES;
 128 module_param(ec_max_queries, uint, 0644);
 129 MODULE_PARM_DESC(ec_max_queries, "Maximum parallel _Qxx evaluations");
 130
 131 static bool ec_busy_polling __read_mostly;
 132 module_param(ec_busy_polling, bool, 0644);
 133 MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction");
 134
 135 static unsigned int ec_polling_guard __read_mostly = ACPI_EC_UDELAY_POLL;
 136 module_param(ec_polling_guard, uint, 0644);
 137 MODULE_PARM_DESC(ec_polling_guard, "Guard time(us) between EC accesses in polling modes");
 138
 139 static unsigned int ec_event_clearing __read_mostly = ACPI_EC_EVT_TIMING_QUERY;
 140
 141 /*
 142  * If the number of false interrupts per one transaction exceeds
 143  * this threshold, will think there is a GPE storm happened and
 144  * will disable the GPE for normal transaction.
 145  */
 146 static unsigned int ec_storm_threshold  __read_mostly = 8;
 147 module_param(ec_storm_threshold, uint, 0644);
 148 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
 149
 150 static bool ec_freeze_events __read_mostly = true;
 151 module_param(ec_freeze_events, bool, 0644);
 152 MODULE_PARM_DESC(ec_freeze_events, "Disabling event handling during suspend/resume");
 153
 154 struct acpi_ec_query_handler {
 155         struct list_head node;
 156         acpi_ec_query_func func;
 157         acpi_handle handle;
 158         void *data;
 159         u8 query_bit;
 160         struct kref kref;
 161 };
 162
 163 struct transaction {
 164         const u8 *wdata;
 165         u8 *rdata;
 166         unsigned short irq_count;
 167         u8 command;
 168         u8 wi;
 169         u8 ri;
 170         u8 wlen;
 171         u8 rlen;
 172         u8 flags;
 173 };
 174
 175 struct acpi_ec_query {
 176         struct transaction transaction;
 177         struct work_struct work;
 178         struct acpi_ec_query_handler *handler;
 179 };
 180
 181 static int acpi_ec_query(struct acpi_ec *ec, u8 *data);
 182 static void advance_transaction(struct acpi_ec *ec);
 183 static void acpi_ec_event_handler(struct work_struct *work);
 184 static void acpi_ec_event_processor(struct work_struct *work);
 185
 186 struct acpi_ec *boot_ec, *first_ec;
 187 EXPORT_SYMBOL(first_ec);
 188 static bool boot_ec_is_ecdt = false;
 189 static struct workqueue_struct *ec_query_wq;
 190
 191 static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
 192 static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
 193
 194 /* --------------------------------------------------------------------------
 195  *                           Logging/Debugging
 196  * -------------------------------------------------------------------------- */
 197
 198 /*
 199  * Splitters used by the developers to track the boundary of the EC
 200  * handling processes.
 201  */
 202 #ifdef DEBUG
 203 #define EC_DBG_SEP      " "
 204 #define EC_DBG_DRV      "+++++"
 205 #define EC_DBG_STM      "====="
 206 #define EC_DBG_REQ      "*****"
 207 #define EC_DBG_EVT      "#####"
 208 #else
 209 #define EC_DBG_SEP      ""
 210 #define EC_DBG_DRV
 211 #define EC_DBG_STM
 212 #define EC_DBG_REQ
 213 #define EC_DBG_EVT
 214 #endif
 215
 216 #define ec_log_raw(fmt, ...) \
 217         pr_info(fmt "\n", ##__VA_ARGS__)
 218 #define ec_dbg_raw(fmt, ...) \
 219         pr_debug(fmt "\n", ##__VA_ARGS__)
 220 #define ec_log(filter, fmt, ...) \
 221         ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
 222 #define ec_dbg(filter, fmt, ...) \
 223         ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
 224
 225 #define ec_log_drv(fmt, ...) \
 226         ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
 227 #define ec_dbg_drv(fmt, ...) \
 228         ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
 229 #define ec_dbg_stm(fmt, ...) \
 230         ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
 231 #define ec_dbg_req(fmt, ...) \
 232         ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
 233 #define ec_dbg_evt(fmt, ...) \
 234         ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
 235 #define ec_dbg_ref(ec, fmt, ...) \
 236         ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
 237
 238 /* --------------------------------------------------------------------------
 239  *                           Device Flags
 240  * -------------------------------------------------------------------------- */
 241
 242 static bool acpi_ec_started(struct acpi_ec *ec)
 243 {
 244         return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
 245                !test_bit(EC_FLAGS_STOPPED, &ec->flags);
 246 }
 247
 248 static bool acpi_ec_event_enabled(struct acpi_ec *ec)
 249 {
 250         /*
 251          * There is an OSPM early stage logic. During the early stages
 252          * (boot/resume), OSPMs shouldn't enable the event handling, only
 253          * the EC transactions are allowed to be performed.
 254          */
 255         if (!test_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 256                 return false;
 257         /*
 258          * However, disabling the event handling is experimental for late
 259          * stage (suspend), and is controlled by the boot parameter of
 260          * "ec_freeze_events":
 261          * 1. true:  The EC event handling is disabled before entering
 262          *           the noirq stage.
 263          * 2. false: The EC event handling is automatically disabled as
 264          *           soon as the EC driver is stopped.
 265          */
 266         if (ec_freeze_events)
 267                 return acpi_ec_started(ec);
 268         else
 269                 return test_bit(EC_FLAGS_STARTED, &ec->flags);
 270 }
 271
 272 static bool acpi_ec_flushed(struct acpi_ec *ec)
 273 {
 274         return ec->reference_count == 1;
 275 }
 276
 277 /* --------------------------------------------------------------------------
 278  *                           EC Registers
 279  * -------------------------------------------------------------------------- */
 280
 281 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
 282 {
 283         u8 x = inb(ec->command_addr);
 284
 285         ec_dbg_raw("EC_SC(R) = 0x%2.2x "
 286                    "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
 287                    x,
 288                    !!(x & ACPI_EC_FLAG_SCI),
 289                    !!(x & ACPI_EC_FLAG_BURST),
 290                    !!(x & ACPI_EC_FLAG_CMD),
 291                    !!(x & ACPI_EC_FLAG_IBF),
 292                    !!(x & ACPI_EC_FLAG_OBF));
 293         return x;
 294 }
 295
 296 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
 297 {
 298         u8 x = inb(ec->data_addr);
 299
 300         ec->timestamp = jiffies;
 301         ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
 302         return x;
 303 }
 304
 305 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
 306 {
 307         ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
 308         outb(command, ec->command_addr);
 309         ec->timestamp = jiffies;
 310 }
 311
 312 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
 313 {
 314         ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
 315         outb(data, ec->data_addr);
 316         ec->timestamp = jiffies;
 317 }
 318
 319 #if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
 320 static const char *acpi_ec_cmd_string(u8 cmd)
 321 {
 322         switch (cmd) {
 323         case 0x80:
 324                 return "RD_EC";
 325         case 0x81:
 326                 return "WR_EC";
 327         case 0x82:
 328                 return "BE_EC";
 329         case 0x83:
 330                 return "BD_EC";
 331         case 0x84:
 332                 return "QR_EC";
 333         }
 334         return "UNKNOWN";
 335 }
 336 #else
 337 #define acpi_ec_cmd_string(cmd)         "UNDEF"
 338 #endif
 339
 340 /* --------------------------------------------------------------------------
 341  *                           GPE Registers
 342  * -------------------------------------------------------------------------- */
 343
 344 static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec)
 345 {
 346         acpi_event_status gpe_status = 0;
 347
 348         (void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
 349         return (gpe_status & ACPI_EVENT_FLAG_STATUS_SET) ? true : false;
 350 }
 351
 352 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
 353 {
 354         if (open)
 355                 acpi_enable_gpe(NULL, ec->gpe);
 356         else {
 357                 BUG_ON(ec->reference_count < 1);
 358                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
 359         }
 360         if (acpi_ec_is_gpe_raised(ec)) {
 361                 /*
 362                  * On some platforms, EN=1 writes cannot trigger GPE. So
 363                  * software need to manually trigger a pseudo GPE event on
 364                  * EN=1 writes.
 365                  */
 366                 ec_dbg_raw("Polling quirk");
 367                 advance_transaction(ec);
 368         }
 369 }
 370
 371 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
 372 {
 373         if (close)
 374                 acpi_disable_gpe(NULL, ec->gpe);
 375         else {
 376                 BUG_ON(ec->reference_count < 1);
 377                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
 378         }
 379 }
 380
 381 static inline void acpi_ec_clear_gpe(struct acpi_ec *ec)
 382 {
 383         /*
 384          * GPE STS is a W1C register, which means:
 385          * 1. Software can clear it without worrying about clearing other
 386          *    GPEs' STS bits when the hardware sets them in parallel.
 387          * 2. As long as software can ensure only clearing it when it is
 388          *    set, hardware won't set it in parallel.
 389          * So software can clear GPE in any contexts.
 390          * Warning: do not move the check into advance_transaction() as the
 391          * EC commands will be sent without GPE raised.
 392          */
 393         if (!acpi_ec_is_gpe_raised(ec))
 394                 return;
 395         acpi_clear_gpe(NULL, ec->gpe);
 396 }
 397
 398 /* --------------------------------------------------------------------------
 399  *                           Transaction Management
 400  * -------------------------------------------------------------------------- */
 401
 402 static void acpi_ec_submit_request(struct acpi_ec *ec)
 403 {
 404         ec->reference_count++;
 405         if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags) &&
 406             ec->reference_count == 1)
 407                 acpi_ec_enable_gpe(ec, true);
 408 }
 409
 410 static void acpi_ec_complete_request(struct acpi_ec *ec)
 411 {
 412         bool flushed = false;
 413
 414         ec->reference_count--;
 415         if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags) &&
 416             ec->reference_count == 0)
 417                 acpi_ec_disable_gpe(ec, true);
 418         flushed = acpi_ec_flushed(ec);
 419         if (flushed)
 420                 wake_up(&ec->wait);
 421 }
 422
 423 static void acpi_ec_set_storm(struct acpi_ec *ec, u8 flag)
 424 {
 425         if (!test_bit(flag, &ec->flags)) {
 426                 acpi_ec_disable_gpe(ec, false);
 427                 ec_dbg_drv("Polling enabled");
 428                 set_bit(flag, &ec->flags);
 429         }
 430 }
 431
 432 static void acpi_ec_clear_storm(struct acpi_ec *ec, u8 flag)
 433 {
 434         if (test_bit(flag, &ec->flags)) {
 435                 clear_bit(flag, &ec->flags);
 436                 acpi_ec_enable_gpe(ec, false);
 437                 ec_dbg_drv("Polling disabled");
 438         }
 439 }
 440
 441 /*
 442  * acpi_ec_submit_flushable_request() - Increase the reference count unless
 443  *                                      the flush operation is not in
 444  *                                      progress
 445  * @ec: the EC device
 446  *
 447  * This function must be used before taking a new action that should hold
 448  * the reference count.  If this function returns false, then the action
 449  * must be discarded or it will prevent the flush operation from being
 450  * completed.
 451  */
 452 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
 453 {
 454         if (!acpi_ec_started(ec))
 455                 return false;
 456         acpi_ec_submit_request(ec);
 457         return true;
 458 }
 459
 460 static void acpi_ec_submit_query(struct acpi_ec *ec)
 461 {
 462         acpi_ec_set_storm(ec, EC_FLAGS_COMMAND_STORM);
 463         if (!acpi_ec_event_enabled(ec))
 464                 return;
 465         if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
 466                 ec_dbg_evt("Command(%s) submitted/blocked",
 467                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 468                 ec->nr_pending_queries++;
 469                 schedule_work(&ec->work);
 470         }
 471 }
 472
 473 static void acpi_ec_complete_query(struct acpi_ec *ec)
 474 {
 475         if (test_and_clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
 476                 ec_dbg_evt("Command(%s) unblocked",
 477                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 478         acpi_ec_clear_storm(ec, EC_FLAGS_COMMAND_STORM);
 479 }
 480
 481 static inline void __acpi_ec_enable_event(struct acpi_ec *ec)
 482 {
 483         if (!test_and_set_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 484                 ec_log_drv("event unblocked");
 485         if (!test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
 486                 advance_transaction(ec);
 487 }
 488
 489 static inline void __acpi_ec_disable_event(struct acpi_ec *ec)
 490 {
 491         if (test_and_clear_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 492                 ec_log_drv("event blocked");
 493 }
 494
 495 static void acpi_ec_enable_event(struct acpi_ec *ec)
 496 {
 497         unsigned long flags;
 498
 499         spin_lock_irqsave(&ec->lock, flags);
 500         if (acpi_ec_started(ec))
 501                 __acpi_ec_enable_event(ec);
 502         spin_unlock_irqrestore(&ec->lock, flags);
 503 }
 504
 505 #ifdef CONFIG_PM_SLEEP
 506 static bool acpi_ec_query_flushed(struct acpi_ec *ec)
 507 {
 508         bool flushed;
 509         unsigned long flags;
 510
 511         spin_lock_irqsave(&ec->lock, flags);
 512         flushed = !ec->nr_pending_queries;
 513         spin_unlock_irqrestore(&ec->lock, flags);
 514         return flushed;
 515 }
 516
 517 static void __acpi_ec_flush_event(struct acpi_ec *ec)
 518 {
 519         /*
 520          * When ec_freeze_events is true, we need to flush events in
 521          * the proper position before entering the noirq stage.
 522          */
 523         wait_event(ec->wait, acpi_ec_query_flushed(ec));
 524         if (ec_query_wq)
 525                 flush_workqueue(ec_query_wq);
 526 }
 527
 528 static void acpi_ec_disable_event(struct acpi_ec *ec)
 529 {
 530         unsigned long flags;
 531
 532         spin_lock_irqsave(&ec->lock, flags);
 533         __acpi_ec_disable_event(ec);
 534         spin_unlock_irqrestore(&ec->lock, flags);
 535         __acpi_ec_flush_event(ec);
 536 }
 537 #endif /* CONFIG_PM_SLEEP */
 538
 539 static bool acpi_ec_guard_event(struct acpi_ec *ec)
 540 {
 541         bool guarded = true;
 542         unsigned long flags;
 543
 544         spin_lock_irqsave(&ec->lock, flags);
 545         /*
 546          * If firmware SCI_EVT clearing timing is "event", we actually
 547          * don't know when the SCI_EVT will be cleared by firmware after
 548          * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
 549          * acceptable period.
 550          *
 551          * The guarding period begins when EC_FLAGS_QUERY_PENDING is
 552          * flagged, which means SCI_EVT check has just been performed.
 553          * But if the current transaction is ACPI_EC_COMMAND_QUERY, the
 554          * guarding should have already been performed (via
 555          * EC_FLAGS_QUERY_GUARDING) and should not be applied so that the
 556          * ACPI_EC_COMMAND_QUERY transaction can be transitioned into
 557          * ACPI_EC_COMMAND_POLL state immediately.
 558          */
 559         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
 560             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY ||
 561             !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) ||
 562             (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY))
 563                 guarded = false;
 564         spin_unlock_irqrestore(&ec->lock, flags);
 565         return guarded;
 566 }
 567
 568 static int ec_transaction_polled(struct acpi_ec *ec)
 569 {
 570         unsigned long flags;
 571         int ret = 0;
 572
 573         spin_lock_irqsave(&ec->lock, flags);
 574         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
 575                 ret = 1;
 576         spin_unlock_irqrestore(&ec->lock, flags);
 577         return ret;
 578 }
 579
 580 static int ec_transaction_completed(struct acpi_ec *ec)
 581 {
 582         unsigned long flags;
 583         int ret = 0;
 584
 585         spin_lock_irqsave(&ec->lock, flags);
 586         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
 587                 ret = 1;
 588         spin_unlock_irqrestore(&ec->lock, flags);
 589         return ret;
 590 }
 591
 592 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
 593 {
 594         ec->curr->flags |= flag;
 595         if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
 596                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS &&
 597                     flag == ACPI_EC_COMMAND_POLL)
 598                         acpi_ec_complete_query(ec);
 599                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY &&
 600                     flag == ACPI_EC_COMMAND_COMPLETE)
 601                         acpi_ec_complete_query(ec);
 602                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 603                     flag == ACPI_EC_COMMAND_COMPLETE)
 604                         set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
 605         }
 606 }
 607
 608 static void advance_transaction(struct acpi_ec *ec)
 609 {
 610         struct transaction *t;
 611         u8 status;
 612         bool wakeup = false;
 613
 614         ec_dbg_stm("%s (%d)", in_interrupt() ? "IRQ" : "TASK",
 615                    smp_processor_id());
 616         /*
 617          * By always clearing STS before handling all indications, we can
 618          * ensure a hardware STS 0->1 change after this clearing can always
 619          * trigger a GPE interrupt.
 620          */
 621         acpi_ec_clear_gpe(ec);
 622         status = acpi_ec_read_status(ec);
 623         t = ec->curr;
 624         /*
 625          * Another IRQ or a guarded polling mode advancement is detected,
 626          * the next QR_EC submission is then allowed.
 627          */
 628         if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
 629                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 630                     (!ec->nr_pending_queries ||
 631                      test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) {
 632                         clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
 633                         acpi_ec_complete_query(ec);
 634                 }
 635         }
 636         if (!t)
 637                 goto err;
 638         if (t->flags & ACPI_EC_COMMAND_POLL) {
 639                 if (t->wlen > t->wi) {
 640                         if ((status & ACPI_EC_FLAG_IBF) == 0)
 641                                 acpi_ec_write_data(ec, t->wdata[t->wi++]);
 642                         else
 643                                 goto err;
 644                 } else if (t->rlen > t->ri) {
 645                         if ((status & ACPI_EC_FLAG_OBF) == 1) {
 646                                 t->rdata[t->ri++] = acpi_ec_read_data(ec);
 647                                 if (t->rlen == t->ri) {
 648                                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 649                                         if (t->command == ACPI_EC_COMMAND_QUERY)
 650                                                 ec_dbg_evt("Command(%s) completed by hardware",
 651                                                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 652                                         wakeup = true;
 653                                 }
 654                         } else
 655                                 goto err;
 656                 } else if (t->wlen == t->wi &&
 657                            (status & ACPI_EC_FLAG_IBF) == 0) {
 658                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 659                         wakeup = true;
 660                 }
 661                 goto out;
 662         } else {
 663                 if (EC_FLAGS_QUERY_HANDSHAKE &&
 664                     !(status & ACPI_EC_FLAG_SCI) &&
 665                     (t->command == ACPI_EC_COMMAND_QUERY)) {
 666                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
 667                         t->rdata[t->ri++] = 0x00;
 668                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 669                         ec_dbg_evt("Command(%s) completed by software",
 670                                    acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 671                         wakeup = true;
 672                 } else if ((status & ACPI_EC_FLAG_IBF) == 0) {
 673                         acpi_ec_write_cmd(ec, t->command);
 674                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
 675                 } else
 676                         goto err;
 677                 goto out;
 678         }
 679 err:
 680         /*
 681          * If SCI bit is set, then don't think it's a false IRQ
 682          * otherwise will take a not handled IRQ as a false one.
 683          */
 684         if (!(status & ACPI_EC_FLAG_SCI)) {
 685                 if (in_interrupt() && t) {
 686                         if (t->irq_count < ec_storm_threshold)
 687                                 ++t->irq_count;
 688                         /* Allow triggering on 0 threshold */
 689                         if (t->irq_count == ec_storm_threshold)
 690                                 acpi_ec_set_storm(ec, EC_FLAGS_COMMAND_STORM);
 691                 }
 692         }
 693 out:
 694         if (status & ACPI_EC_FLAG_SCI)
 695                 acpi_ec_submit_query(ec);
 696         if (wakeup && in_interrupt())
 697                 wake_up(&ec->wait);
 698 }
 699
 700 static void start_transaction(struct acpi_ec *ec)
 701 {
 702         ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
 703         ec->curr->flags = 0;
 704 }
 705
 706 static int ec_guard(struct acpi_ec *ec)
 707 {
 708         unsigned long guard = usecs_to_jiffies(ec->polling_guard);
 709         unsigned long timeout = ec->timestamp + guard;
 710
 711         /* Ensure guarding period before polling EC status */
 712         do {
 713                 if (ec->busy_polling) {
 714                         /* Perform busy polling */
 715                         if (ec_transaction_completed(ec))
 716                                 return 0;
 717                         udelay(jiffies_to_usecs(guard));
 718                 } else {
 719                         /*
 720                          * Perform wait polling
 721                          * 1. Wait the transaction to be completed by the
 722                          *    GPE handler after the transaction enters
 723                          *    ACPI_EC_COMMAND_POLL state.
 724                          * 2. A special guarding logic is also required
 725                          *    for event clearing mode "event" before the
 726                          *    transaction enters ACPI_EC_COMMAND_POLL
 727                          *    state.
 728                          */
 729                         if (!ec_transaction_polled(ec) &&
 730                             !acpi_ec_guard_event(ec))
 731                                 break;
 732                         if (wait_event_timeout(ec->wait,
 733                                                ec_transaction_completed(ec),
 734                                                guard))
 735                                 return 0;
 736                 }
 737         } while (time_before(jiffies, timeout));
 738         return -ETIME;
 739 }
 740
 741 static int ec_poll(struct acpi_ec *ec)
 742 {
 743         unsigned long flags;
 744         int repeat = 5; /* number of command restarts */
 745
 746         while (repeat--) {
 747                 unsigned long delay = jiffies +
 748                         msecs_to_jiffies(ec_delay);
 749                 do {
 750                         if (!ec_guard(ec))
 751                                 return 0;
 752                         spin_lock_irqsave(&ec->lock, flags);
 753                         advance_transaction(ec);
 754                         spin_unlock_irqrestore(&ec->lock, flags);
 755                 } while (time_before(jiffies, delay));
 756                 pr_debug("controller reset, restart transaction\n");
 757                 spin_lock_irqsave(&ec->lock, flags);
 758                 start_transaction(ec);
 759                 spin_unlock_irqrestore(&ec->lock, flags);
 760         }
 761         return -ETIME;
 762 }
 763
 764 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
 765                                         struct transaction *t)
 766 {
 767         unsigned long tmp;
 768         int ret = 0;
 769
 770         /* start transaction */
 771         spin_lock_irqsave(&ec->lock, tmp);
 772         /* Enable GPE for command processing (IBF=0/OBF=1) */
 773         if (!acpi_ec_submit_flushable_request(ec)) {
 774                 ret = -EINVAL;
 775                 goto unlock;
 776         }
 777         ec_dbg_ref(ec, "Increase command");
 778         /* following two actions should be kept atomic */
 779         ec->curr = t;
 780         ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
 781         start_transaction(ec);
 782         spin_unlock_irqrestore(&ec->lock, tmp);
 783
 784         ret = ec_poll(ec);
 785
 786         spin_lock_irqsave(&ec->lock, tmp);
 787         if (t->irq_count == ec_storm_threshold)
 788                 acpi_ec_clear_storm(ec, EC_FLAGS_COMMAND_STORM);
 789         ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
 790         ec->curr = NULL;
 791         /* Disable GPE for command processing (IBF=0/OBF=1) */
 792         acpi_ec_complete_request(ec);
 793         ec_dbg_ref(ec, "Decrease command");
 794 unlock:
 795         spin_unlock_irqrestore(&ec->lock, tmp);
 796         return ret;
 797 }
 798
 799 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
 800 {
 801         int status;
 802         u32 glk;
 803
 804         if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
 805                 return -EINVAL;
 806         if (t->rdata)
 807                 memset(t->rdata, 0, t->rlen);
 808
 809         mutex_lock(&ec->mutex);
 810         if (ec->global_lock) {
 811                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
 812                 if (ACPI_FAILURE(status)) {
 813                         status = -ENODEV;
 814                         goto unlock;
 815                 }
 816         }
 817
 818         status = acpi_ec_transaction_unlocked(ec, t);
 819
 820         if (ec->global_lock)
 821                 acpi_release_global_lock(glk);
 822 unlock:
 823         mutex_unlock(&ec->mutex);
 824         return status;
 825 }
 826
 827 static int acpi_ec_burst_enable(struct acpi_ec *ec)
 828 {
 829         u8 d;
 830         struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
 831                                 .wdata = NULL, .rdata = &d,
 832                                 .wlen = 0, .rlen = 1};
 833
 834         return acpi_ec_transaction(ec, &t);
 835 }
 836
 837 static int acpi_ec_burst_disable(struct acpi_ec *ec)
 838 {
 839         struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
 840                                 .wdata = NULL, .rdata = NULL,
 841                                 .wlen = 0, .rlen = 0};
 842
 843         return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
 844                                 acpi_ec_transaction(ec, &t) : 0;
 845 }
 846
 847 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
 848 {
 849         int result;
 850         u8 d;
 851         struct transaction t = {.command = ACPI_EC_COMMAND_READ,
 852                                 .wdata = &address, .rdata = &d,
 853                                 .wlen = 1, .rlen = 1};
 854
 855         result = acpi_ec_transaction(ec, &t);
 856         *data = d;
 857         return result;
 858 }
 859
 860 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
 861 {
 862         u8 wdata[2] = { address, data };
 863         struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
 864                                 .wdata = wdata, .rdata = NULL,
 865                                 .wlen = 2, .rlen = 0};
 866
 867         return acpi_ec_transaction(ec, &t);
 868 }
 869
 870 int ec_read(u8 addr, u8 *val)
 871 {
 872         int err;
 873         u8 temp_data;
 874
 875         if (!first_ec)
 876                 return -ENODEV;
 877
 878         err = acpi_ec_read(first_ec, addr, &temp_data);
 879
 880         if (!err) {
 881                 *val = temp_data;
 882                 return 0;
 883         }
 884         return err;
 885 }
 886 EXPORT_SYMBOL(ec_read);
 887
 888 int ec_write(u8 addr, u8 val)
 889 {
 890         int err;
 891
 892         if (!first_ec)
 893                 return -ENODEV;
 894
 895         err = acpi_ec_write(first_ec, addr, val);
 896
 897         return err;
 898 }
 899 EXPORT_SYMBOL(ec_write);
 900
 901 int ec_transaction(u8 command,
 902                    const u8 *wdata, unsigned wdata_len,
 903                    u8 *rdata, unsigned rdata_len)
 904 {
 905         struct transaction t = {.command = command,
 906                                 .wdata = wdata, .rdata = rdata,
 907                                 .wlen = wdata_len, .rlen = rdata_len};
 908
 909         if (!first_ec)
 910                 return -ENODEV;
 911
 912         return acpi_ec_transaction(first_ec, &t);
 913 }
 914 EXPORT_SYMBOL(ec_transaction);
 915
 916 /* Get the handle to the EC device */
 917 acpi_handle ec_get_handle(void)
 918 {
 919         if (!first_ec)
 920                 return NULL;
 921         return first_ec->handle;
 922 }
 923 EXPORT_SYMBOL(ec_get_handle);
 924
 925 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
 926 {
 927         unsigned long flags;
 928
 929         spin_lock_irqsave(&ec->lock, flags);
 930         if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
 931                 ec_dbg_drv("Starting EC");
 932                 /* Enable GPE for event processing (SCI_EVT=1) */
 933                 if (!resuming) {
 934                         acpi_ec_submit_request(ec);
 935                         ec_dbg_ref(ec, "Increase driver");
 936                 }
 937                 ec_log_drv("EC started");
 938         }
 939         spin_unlock_irqrestore(&ec->lock, flags);
 940 }
 941
 942 static bool acpi_ec_stopped(struct acpi_ec *ec)
 943 {
 944         unsigned long flags;
 945         bool flushed;
 946
 947         spin_lock_irqsave(&ec->lock, flags);
 948         flushed = acpi_ec_flushed(ec);
 949         spin_unlock_irqrestore(&ec->lock, flags);
 950         return flushed;
 951 }
 952
 953 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
 954 {
 955         unsigned long flags;
 956
 957         spin_lock_irqsave(&ec->lock, flags);
 958         if (acpi_ec_started(ec)) {
 959                 ec_dbg_drv("Stopping EC");
 960                 set_bit(EC_FLAGS_STOPPED, &ec->flags);
 961                 spin_unlock_irqrestore(&ec->lock, flags);
 962                 wait_event(ec->wait, acpi_ec_stopped(ec));
 963                 spin_lock_irqsave(&ec->lock, flags);
 964                 /* Disable GPE for event processing (SCI_EVT=1) */
 965                 if (!suspending) {
 966                         acpi_ec_complete_request(ec);
 967                         ec_dbg_ref(ec, "Decrease driver");
 968                 } else if (!ec_freeze_events)
 969                         __acpi_ec_disable_event(ec);
 970                 clear_bit(EC_FLAGS_STARTED, &ec->flags);
 971                 clear_bit(EC_FLAGS_STOPPED, &ec->flags);
 972                 ec_log_drv("EC stopped");
 973         }
 974         spin_unlock_irqrestore(&ec->lock, flags);
 975 }
 976
 977 static void acpi_ec_enter_noirq(struct acpi_ec *ec)
 978 {
 979         unsigned long flags;
 980
 981         spin_lock_irqsave(&ec->lock, flags);
 982         ec->busy_polling = true;
 983         ec->polling_guard = 0;
 984         ec_log_drv("interrupt blocked");
 985         spin_unlock_irqrestore(&ec->lock, flags);
 986 }
 987
 988 static void acpi_ec_leave_noirq(struct acpi_ec *ec)
 989 {
 990         unsigned long flags;
 991
 992         spin_lock_irqsave(&ec->lock, flags);
 993         ec->busy_polling = ec_busy_polling;
 994         ec->polling_guard = ec_polling_guard;
 995         ec_log_drv("interrupt unblocked");
 996         spin_unlock_irqrestore(&ec->lock, flags);
 997 }
 998
 999 void acpi_ec_block_transactions(void)
1000 {
1001         struct acpi_ec *ec = first_ec;
1002
1003         if (!ec)
1004                 return;
1005
1006         mutex_lock(&ec->mutex);
1007         /* Prevent transactions from being carried out */
1008         acpi_ec_stop(ec, true);
1009         mutex_unlock(&ec->mutex);
1010 }
1011
1012 void acpi_ec_unblock_transactions(void)
1013 {
1014         /*
1015          * Allow transactions to happen again (this function is called from
1016          * atomic context during wakeup, so we don't need to acquire the mutex).
1017          */
1018         if (first_ec)
1019                 acpi_ec_start(first_ec, true);
1020 }
1021
1022 /* --------------------------------------------------------------------------
1023                                 Event Management
1024    -------------------------------------------------------------------------- */
1025 static struct acpi_ec_query_handler *
1026 acpi_ec_get_query_handler(struct acpi_ec_query_handler *handler)
1027 {
1028         if (handler)
1029                 kref_get(&handler->kref);
1030         return handler;
1031 }
1032
1033 static struct acpi_ec_query_handler *
1034 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
1035 {
1036         struct acpi_ec_query_handler *handler;
1037         bool found = false;
1038
1039         mutex_lock(&ec->mutex);
1040         list_for_each_entry(handler, &ec->list, node) {
1041                 if (value == handler->query_bit) {
1042                         found = true;
1043                         break;
1044                 }
1045         }
1046         mutex_unlock(&ec->mutex);
1047         return found ? acpi_ec_get_query_handler(handler) : NULL;
1048 }
1049
1050 static void acpi_ec_query_handler_release(struct kref *kref)
1051 {
1052         struct acpi_ec_query_handler *handler =
1053                 container_of(kref, struct acpi_ec_query_handler, kref);
1054
1055         kfree(handler);
1056 }
1057
1058 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
1059 {
1060         kref_put(&handler->kref, acpi_ec_query_handler_release);
1061 }
1062
1063 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
1064                               acpi_handle handle, acpi_ec_query_func func,
1065                               void *data)
1066 {
1067         struct acpi_ec_query_handler *handler =
1068             kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
1069
1070         if (!handler)
1071                 return -ENOMEM;
1072
1073         handler->query_bit = query_bit;
1074         handler->handle = handle;
1075         handler->func = func;
1076         handler->data = data;
1077         mutex_lock(&ec->mutex);
1078         kref_init(&handler->kref);
1079         list_add(&handler->node, &ec->list);
1080         mutex_unlock(&ec->mutex);
1081         return 0;
1082 }
1083 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1084
1085 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1086                                           bool remove_all, u8 query_bit)
1087 {
1088         struct acpi_ec_query_handler *handler, *tmp;
1089         LIST_HEAD(free_list);
1090
1091         mutex_lock(&ec->mutex);
1092         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1093                 if (remove_all || query_bit == handler->query_bit) {
1094                         list_del_init(&handler->node);
1095                         list_add(&handler->node, &free_list);
1096                 }
1097         }
1098         mutex_unlock(&ec->mutex);
1099         list_for_each_entry_safe(handler, tmp, &free_list, node)
1100                 acpi_ec_put_query_handler(handler);
1101 }
1102
1103 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1104 {
1105         acpi_ec_remove_query_handlers(ec, false, query_bit);
1106 }
1107 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1108
1109 static struct acpi_ec_query *acpi_ec_create_query(u8 *pval)
1110 {
1111         struct acpi_ec_query *q;
1112         struct transaction *t;
1113
1114         q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1115         if (!q)
1116                 return NULL;
1117         INIT_WORK(&q->work, acpi_ec_event_processor);
1118         t = &q->transaction;
1119         t->command = ACPI_EC_COMMAND_QUERY;
1120         t->rdata = pval;
1121         t->rlen = 1;
1122         return q;
1123 }
1124
1125 static void acpi_ec_delete_query(struct acpi_ec_query *q)
1126 {
1127         if (q) {
1128                 if (q->handler)
1129                         acpi_ec_put_query_handler(q->handler);
1130                 kfree(q);
1131         }
1132 }
1133
1134 static void acpi_ec_event_processor(struct work_struct *work)
1135 {
1136         struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1137         struct acpi_ec_query_handler *handler = q->handler;
1138
1139         ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1140         if (handler->func)
1141                 handler->func(handler->data);
1142         else if (handler->handle)
1143                 acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1144         ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1145         acpi_ec_delete_query(q);
1146 }
1147
1148 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
1149 {
1150         u8 value = 0;
1151         int result;
1152         struct acpi_ec_query *q;
1153
1154         q = acpi_ec_create_query(&value);
1155         if (!q)
1156                 return -ENOMEM;
1157
1158         /*
1159          * Query the EC to find out which _Qxx method we need to evaluate.
1160          * Note that successful completion of the query causes the ACPI_EC_SCI
1161          * bit to be cleared (and thus clearing the interrupt source).
1162          */
1163         result = acpi_ec_transaction(ec, &q->transaction);
1164         if (!value)
1165                 result = -ENODATA;
1166         if (result)
1167                 goto err_exit;
1168
1169         q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1170         if (!q->handler) {
1171                 result = -ENODATA;
1172                 goto err_exit;
1173         }
1174
1175         /*
1176          * It is reported that _Qxx are evaluated in a parallel way on
1177          * Windows:
1178          * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1179          *
1180          * Put this log entry before schedule_work() in order to make
1181          * it appearing before any other log entries occurred during the
1182          * work queue execution.
1183          */
1184         ec_dbg_evt("Query(0x%02x) scheduled", value);
1185         if (!queue_work(ec_query_wq, &q->work)) {
1186                 ec_dbg_evt("Query(0x%02x) overlapped", value);
1187                 result = -EBUSY;
1188         }
1189
1190 err_exit:
1191         if (result)
1192                 acpi_ec_delete_query(q);
1193         if (data)
1194                 *data = value;
1195         return result;
1196 }
1197
1198 static void acpi_ec_check_event(struct acpi_ec *ec)
1199 {
1200         unsigned long flags;
1201
1202         if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1203                 if (ec_guard(ec)) {
1204                         spin_lock_irqsave(&ec->lock, flags);
1205                         /*
1206                          * Take care of the SCI_EVT unless no one else is
1207                          * taking care of it.
1208                          */
1209                         if (!ec->curr)
1210                                 advance_transaction(ec);
1211                         spin_unlock_irqrestore(&ec->lock, flags);
1212                 }
1213         }
1214 }
1215
1216 static void acpi_ec_event_handler(struct work_struct *work)
1217 {
1218         unsigned long flags;
1219         struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1220
1221         ec_dbg_evt("Event started");
1222
1223         spin_lock_irqsave(&ec->lock, flags);
1224         while (ec->nr_pending_queries) {
1225                 spin_unlock_irqrestore(&ec->lock, flags);
1226                 (void)acpi_ec_query(ec, NULL);
1227                 spin_lock_irqsave(&ec->lock, flags);
1228                 ec->nr_pending_queries--;
1229                 /*
1230                  * Before exit, make sure that this work item can be
1231                  * scheduled again. There might be QR_EC failures, leaving
1232                  * EC_FLAGS_QUERY_PENDING uncleared and preventing this work
1233                  * item from being scheduled again.
1234                  */
1235                 if (!ec->nr_pending_queries) {
1236                         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
1237                             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY)
1238                                 acpi_ec_complete_query(ec);
1239                 }
1240         }
1241         spin_unlock_irqrestore(&ec->lock, flags);
1242
1243         ec_dbg_evt("Event stopped");
1244
1245         acpi_ec_check_event(ec);
1246 }
1247
1248 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1249         u32 gpe_number, void *data)
1250 {
1251         unsigned long flags;
1252         struct acpi_ec *ec = data;
1253
1254         spin_lock_irqsave(&ec->lock, flags);
1255         advance_transaction(ec);
1256         spin_unlock_irqrestore(&ec->lock, flags);
1257         return ACPI_INTERRUPT_HANDLED;
1258 }
1259
1260 /* --------------------------------------------------------------------------
1261  *                           Address Space Management
1262  * -------------------------------------------------------------------------- */
1263
1264 static acpi_status
1265 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1266                       u32 bits, u64 *value64,
1267                       void *handler_context, void *region_context)
1268 {
1269         struct acpi_ec *ec = handler_context;
1270         int result = 0, i, bytes = bits / 8;
1271         u8 *value = (u8 *)value64;
1272
1273         if ((address > 0xFF) || !value || !handler_context)
1274                 return AE_BAD_PARAMETER;
1275
1276         if (function != ACPI_READ && function != ACPI_WRITE)
1277                 return AE_BAD_PARAMETER;
1278
1279         if (ec->busy_polling || bits > 8)
1280                 acpi_ec_burst_enable(ec);
1281
1282         for (i = 0; i < bytes; ++i, ++address, ++value)
1283                 result = (function == ACPI_READ) ?
1284                         acpi_ec_read(ec, address, value) :
1285                         acpi_ec_write(ec, address, *value);
1286
1287         if (ec->busy_polling || bits > 8)
1288                 acpi_ec_burst_disable(ec);
1289
1290         switch (result) {
1291         case -EINVAL:
1292                 return AE_BAD_PARAMETER;
1293         case -ENODEV:
1294                 return AE_NOT_FOUND;
1295         case -ETIME:
1296                 return AE_TIME;
1297         default:
1298                 return AE_OK;
1299         }
1300 }
1301
1302 /* --------------------------------------------------------------------------
1303  *                             Driver Interface
1304  * -------------------------------------------------------------------------- */
1305
1306 static acpi_status
1307 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1308
1309 static void acpi_ec_free(struct acpi_ec *ec)
1310 {
1311         if (first_ec == ec)
1312                 first_ec = NULL;
1313         if (boot_ec == ec)
1314                 boot_ec = NULL;
1315         kfree(ec);
1316 }
1317
1318 static struct acpi_ec *acpi_ec_alloc(void)
1319 {
1320         struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1321
1322         if (!ec)
1323                 return NULL;
1324         mutex_init(&ec->mutex);
1325         init_waitqueue_head(&ec->wait);
1326         INIT_LIST_HEAD(&ec->list);
1327         spin_lock_init(&ec->lock);
1328         INIT_WORK(&ec->work, acpi_ec_event_handler);
1329         ec->timestamp = jiffies;
1330         ec->busy_polling = true;
1331         ec->polling_guard = 0;
1332         return ec;
1333 }
1334
1335 static acpi_status
1336 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1337                                void *context, void **return_value)
1338 {
1339         char node_name[5];
1340         struct acpi_buffer buffer = { sizeof(node_name), node_name };
1341         struct acpi_ec *ec = context;
1342         int value = 0;
1343         acpi_status status;
1344
1345         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1346
1347         if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1348                 acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1349         return AE_OK;
1350 }
1351
1352 static acpi_status
1353 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1354 {
1355         acpi_status status;
1356         unsigned long long tmp = 0;
1357         struct acpi_ec *ec = context;
1358
1359         /* clear addr values, ec_parse_io_ports depend on it */
1360         ec->command_addr = ec->data_addr = 0;
1361
1362         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1363                                      ec_parse_io_ports, ec);
1364         if (ACPI_FAILURE(status))
1365                 return status;
1366         if (ec->data_addr == 0 || ec->command_addr == 0)
1367                 return AE_OK;
1368
1369         /* Get GPE bit assignment (EC events). */
1370         /* TODO: Add support for _GPE returning a package */
1371         status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1372         if (ACPI_FAILURE(status))
1373                 return status;
1374         ec->gpe = tmp;
1375         /* Use the global lock for all EC transactions? */
1376         tmp = 0;
1377         acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1378         ec->global_lock = tmp;
1379         ec->handle = handle;
1380         return AE_CTRL_TERMINATE;
1381 }
1382
1383 /*
1384  * Note: This function returns an error code only when the address space
1385  *       handler is not installed, which means "not able to handle
1386  *       transactions".
1387  */
1388 static int ec_install_handlers(struct acpi_ec *ec, bool handle_events)
1389 {
1390         acpi_status status;
1391
1392         acpi_ec_start(ec, false);
1393
1394         if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1395                 acpi_ec_enter_noirq(ec);
1396                 status = acpi_install_address_space_handler(ec->handle,
1397                                                             ACPI_ADR_SPACE_EC,
1398                                                             &acpi_ec_space_handler,
1399                                                             NULL, ec);
1400                 if (ACPI_FAILURE(status)) {
1401                         if (status == AE_NOT_FOUND) {
1402                                 /*
1403                                  * Maybe OS fails in evaluating the _REG
1404                                  * object. The AE_NOT_FOUND error will be
1405                                  * ignored and OS * continue to initialize
1406                                  * EC.
1407                                  */
1408                                 pr_err("Fail in evaluating the _REG object"
1409                                         " of EC device. Broken bios is suspected.\n");
1410                         } else {
1411                                 acpi_ec_stop(ec, false);
1412                                 return -ENODEV;
1413                         }
1414                 }
1415                 set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1416         }
1417
1418         if (!handle_events)
1419                 return 0;
1420
1421         if (!test_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags)) {
1422                 /* Find and register all query methods */
1423                 acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1424                                     acpi_ec_register_query_methods,
1425                                     NULL, ec, NULL);
1426                 set_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags);
1427         }
1428         if (!test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
1429                 status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1430                                           ACPI_GPE_EDGE_TRIGGERED,
1431                                           &acpi_ec_gpe_handler, ec);
1432                 /* This is not fatal as we can poll EC events */
1433                 if (ACPI_SUCCESS(status)) {
1434                         set_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
1435                         acpi_ec_leave_noirq(ec);
1436                         if (test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1437                             ec->reference_count >= 1)
1438                                 acpi_ec_enable_gpe(ec, true);
1439
1440                         /* EC is fully operational, allow queries */
1441                         acpi_ec_enable_event(ec);
1442                 }
1443         }
1444
1445         return 0;
1446 }
1447
1448 static void ec_remove_handlers(struct acpi_ec *ec)
1449 {
1450         if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1451                 if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1452                                         ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1453                         pr_err("failed to remove space handler\n");
1454                 clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1455         }
1456
1457         /*
1458          * Stops handling the EC transactions after removing the operation
1459          * region handler. This is required because _REG(DISCONNECT)
1460          * invoked during the removal can result in new EC transactions.
1461          *
1462          * Flushes the EC requests and thus disables the GPE before
1463          * removing the GPE handler. This is required by the current ACPICA
1464          * GPE core. ACPICA GPE core will automatically disable a GPE when
1465          * it is indicated but there is no way to handle it. So the drivers
1466          * must disable the GPEs prior to removing the GPE handlers.
1467          */
1468         acpi_ec_stop(ec, false);
1469
1470         if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
1471                 if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1472                                         &acpi_ec_gpe_handler)))
1473                         pr_err("failed to remove gpe handler\n");
1474                 clear_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
1475         }
1476         if (test_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags)) {
1477                 acpi_ec_remove_query_handlers(ec, true, 0);
1478                 clear_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags);
1479         }
1480 }
1481
1482 static int acpi_ec_setup(struct acpi_ec *ec, bool handle_events)
1483 {
1484         int ret;
1485
1486         ret = ec_install_handlers(ec, handle_events);
1487         if (ret)
1488                 return ret;
1489
1490         /* First EC capable of handling transactions */
1491         if (!first_ec) {
1492                 first_ec = ec;
1493                 acpi_handle_info(first_ec->handle, "Used as first EC\n");
1494         }
1495
1496         acpi_handle_info(ec->handle,
1497                          "GPE=0x%lx, EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n",
1498                          ec->gpe, ec->command_addr, ec->data_addr);
1499         return ret;
1500 }
1501
1502 static int acpi_config_boot_ec(struct acpi_ec *ec, acpi_handle handle,
1503                                bool handle_events, bool is_ecdt)
1504 {
1505         int ret;
1506
1507         /*
1508          * Changing the ACPI handle results in a re-configuration of the
1509          * boot EC. And if it happens after the namespace initialization,
1510          * it causes _REG evaluations.
1511          */
1512         if (boot_ec && boot_ec->handle != handle)
1513                 ec_remove_handlers(boot_ec);
1514
1515         /* Unset old boot EC */
1516         if (boot_ec != ec)
1517                 acpi_ec_free(boot_ec);
1518
1519         /*
1520          * ECDT device creation is split into acpi_ec_ecdt_probe() and
1521          * acpi_ec_ecdt_start(). This function takes care of completing the
1522          * ECDT parsing logic as the handle update should be performed
1523          * between the installation/uninstallation of the handlers.
1524          */
1525         if (ec->handle != handle)
1526                 ec->handle = handle;
1527
1528         ret = acpi_ec_setup(ec, handle_events);
1529         if (ret)
1530                 return ret;
1531
1532         /* Set new boot EC */
1533         if (!boot_ec) {
1534                 boot_ec = ec;
1535                 boot_ec_is_ecdt = is_ecdt;
1536         }
1537
1538         acpi_handle_info(boot_ec->handle,
1539                          "Used as boot %s EC to handle transactions%s\n",
1540                          is_ecdt ? "ECDT" : "DSDT",
1541                          handle_events ? " and events" : "");
1542         return ret;
1543 }
1544
1545 static bool acpi_ec_ecdt_get_handle(acpi_handle *phandle)
1546 {
1547         struct acpi_table_ecdt *ecdt_ptr;
1548         acpi_status status;
1549         acpi_handle handle;
1550
1551         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1552                                 (struct acpi_table_header **)&ecdt_ptr);
1553         if (ACPI_FAILURE(status))
1554                 return false;
1555
1556         status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
1557         if (ACPI_FAILURE(status))
1558                 return false;
1559
1560         *phandle = handle;
1561         return true;
1562 }
1563
1564 static bool acpi_is_boot_ec(struct acpi_ec *ec)
1565 {
1566         if (!boot_ec)
1567                 return false;
1568         if (ec->handle == boot_ec->handle &&
1569             ec->gpe == boot_ec->gpe &&
1570             ec->command_addr == boot_ec->command_addr &&
1571             ec->data_addr == boot_ec->data_addr)
1572                 return true;
1573         return false;
1574 }
1575
1576 static int acpi_ec_add(struct acpi_device *device)
1577 {
1578         struct acpi_ec *ec = NULL;
1579         int ret;
1580
1581         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1582         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1583
1584         ec = acpi_ec_alloc();
1585         if (!ec)
1586                 return -ENOMEM;
1587         if (ec_parse_device(device->handle, 0, ec, NULL) !=
1588                 AE_CTRL_TERMINATE) {
1589                         ret = -EINVAL;
1590                         goto err_alloc;
1591         }
1592
1593         if (acpi_is_boot_ec(ec)) {
1594                 boot_ec_is_ecdt = false;
1595                 acpi_handle_debug(ec->handle, "duplicated.\n");
1596                 acpi_ec_free(ec);
1597                 ec = boot_ec;
1598                 ret = acpi_config_boot_ec(ec, ec->handle, true, false);
1599         } else
1600                 ret = acpi_ec_setup(ec, true);
1601         if (ret)
1602                 goto err_query;
1603
1604         device->driver_data = ec;
1605
1606         ret = !!request_region(ec->data_addr, 1, "EC data");
1607         WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1608         ret = !!request_region(ec->command_addr, 1, "EC cmd");
1609         WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1610
1611         /* Reprobe devices depending on the EC */
1612         acpi_walk_dep_device_list(ec->handle);
1613         acpi_handle_debug(ec->handle, "enumerated.\n");
1614         return 0;
1615
1616 err_query:
1617         if (ec != boot_ec)
1618                 acpi_ec_remove_query_handlers(ec, true, 0);
1619 err_alloc:
1620         if (ec != boot_ec)
1621                 acpi_ec_free(ec);
1622         return ret;
1623 }
1624
1625 static int acpi_ec_remove(struct acpi_device *device)
1626 {
1627         struct acpi_ec *ec;
1628
1629         if (!device)
1630                 return -EINVAL;
1631
1632         ec = acpi_driver_data(device);
1633         release_region(ec->data_addr, 1);
1634         release_region(ec->command_addr, 1);
1635         device->driver_data = NULL;
1636         if (ec != boot_ec) {
1637                 ec_remove_handlers(ec);
1638                 acpi_ec_free(ec);
1639         }
1640         return 0;
1641 }
1642
1643 static acpi_status
1644 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1645 {
1646         struct acpi_ec *ec = context;
1647
1648         if (resource->type != ACPI_RESOURCE_TYPE_IO)
1649                 return AE_OK;
1650
1651         /*
1652          * The first address region returned is the data port, and
1653          * the second address region returned is the status/command
1654          * port.
1655          */
1656         if (ec->data_addr == 0)
1657                 ec->data_addr = resource->data.io.minimum;
1658         else if (ec->command_addr == 0)
1659                 ec->command_addr = resource->data.io.minimum;
1660         else
1661                 return AE_CTRL_TERMINATE;
1662
1663         return AE_OK;
1664 }
1665
1666 static const struct acpi_device_id ec_device_ids[] = {
1667         {"PNP0C09", 0},
1668         {"", 0},
1669 };
1670
1671 /*
1672  * This function is not Windows-compatible as Windows never enumerates the
1673  * namespace EC before the main ACPI device enumeration process. It is
1674  * retained for historical reason and will be deprecated in the future.
1675  */
1676 int __init acpi_ec_dsdt_probe(void)
1677 {
1678         acpi_status status;
1679         struct acpi_ec *ec;
1680         int ret;
1681
1682         /*
1683          * If a platform has ECDT, there is no need to proceed as the
1684          * following probe is not a part of the ACPI device enumeration,
1685          * executing _STA is not safe, and thus this probe may risk of
1686          * picking up an invalid EC device.
1687          */
1688         if (boot_ec)
1689                 return -ENODEV;
1690
1691         ec = acpi_ec_alloc();
1692         if (!ec)
1693                 return -ENOMEM;
1694         /*
1695          * At this point, the namespace is initialized, so start to find
1696          * the namespace objects.
1697          */
1698         status = acpi_get_devices(ec_device_ids[0].id,
1699                                   ec_parse_device, ec, NULL);
1700         if (ACPI_FAILURE(status) || !ec->handle) {
1701                 ret = -ENODEV;
1702                 goto error;
1703         }
1704         /*
1705          * When the DSDT EC is available, always re-configure boot EC to
1706          * have _REG evaluated. _REG can only be evaluated after the
1707          * namespace initialization.
1708          * At this point, the GPE is not fully initialized, so do not to
1709          * handle the events.
1710          */
1711         ret = acpi_config_boot_ec(ec, ec->handle, false, false);
1712 error:
1713         if (ret)
1714                 acpi_ec_free(ec);
1715         return ret;
1716 }
1717
1718 /*
1719  * If the DSDT EC is not functioning, we still need to prepare a fully
1720  * functioning ECDT EC first in order to handle the events.
1721  * https://bugzilla.kernel.org/show_bug.cgi?id=115021
1722  */
1723 int __init acpi_ec_ecdt_start(void)
1724 {
1725         acpi_handle handle;
1726
1727         if (!boot_ec)
1728                 return -ENODEV;
1729         /*
1730          * The DSDT EC should have already been started in
1731          * acpi_ec_add().
1732          */
1733         if (!boot_ec_is_ecdt)
1734                 return -ENODEV;
1735
1736         /*
1737          * At this point, the namespace and the GPE is initialized, so
1738          * start to find the namespace objects and handle the events.
1739          */
1740         if (!acpi_ec_ecdt_get_handle(&handle))
1741                 return -ENODEV;
1742         return acpi_config_boot_ec(boot_ec, handle, true, true);
1743 }
1744
1745 #if 0
1746 /*
1747  * Some EC firmware variations refuses to respond QR_EC when SCI_EVT is not
1748  * set, for which case, we complete the QR_EC without issuing it to the
1749  * firmware.
1750  * https://bugzilla.kernel.org/show_bug.cgi?id=82611
1751  * https://bugzilla.kernel.org/show_bug.cgi?id=97381
1752  */
1753 static int ec_flag_query_handshake(const struct dmi_system_id *id)
1754 {
1755         pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
1756         EC_FLAGS_QUERY_HANDSHAKE = 1;
1757         return 0;
1758 }
1759 #endif
1760
1761 /*
1762  * Some ECDTs contain wrong register addresses.
1763  * MSI MS-171F
1764  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1765  */
1766 static int ec_correct_ecdt(const struct dmi_system_id *id)
1767 {
1768         pr_debug("Detected system needing ECDT address correction.\n");
1769         EC_FLAGS_CORRECT_ECDT = 1;
1770         return 0;
1771 }
1772
1773 static struct dmi_system_id ec_dmi_table[] __initdata = {
1774         {
1775         ec_correct_ecdt, "MSI MS-171F", {
1776         DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1777         DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
1778         {},
1779 };
1780
1781 int __init acpi_ec_ecdt_probe(void)
1782 {
1783         int ret;
1784         acpi_status status;
1785         struct acpi_table_ecdt *ecdt_ptr;
1786         struct acpi_ec *ec;
1787
1788         ec = acpi_ec_alloc();
1789         if (!ec)
1790                 return -ENOMEM;
1791         /*
1792          * Generate a boot ec context
1793          */
1794         dmi_check_system(ec_dmi_table);
1795         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1796                                 (struct acpi_table_header **)&ecdt_ptr);
1797         if (ACPI_FAILURE(status)) {
1798                 ret = -ENODEV;
1799                 goto error;
1800         }
1801
1802         if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
1803                 /*
1804                  * Asus X50GL:
1805                  * https://bugzilla.kernel.org/show_bug.cgi?id=11880
1806                  */
1807                 ret = -ENODEV;
1808                 goto error;
1809         }
1810
1811         if (EC_FLAGS_CORRECT_ECDT) {
1812                 ec->command_addr = ecdt_ptr->data.address;
1813                 ec->data_addr = ecdt_ptr->control.address;
1814         } else {
1815                 ec->command_addr = ecdt_ptr->control.address;
1816                 ec->data_addr = ecdt_ptr->data.address;
1817         }
1818         ec->gpe = ecdt_ptr->gpe;
1819
1820         /*
1821          * At this point, the namespace is not initialized, so do not find
1822          * the namespace objects, or handle the events.
1823          */
1824         ret = acpi_config_boot_ec(ec, ACPI_ROOT_OBJECT, false, true);
1825 error:
1826         if (ret)
1827                 acpi_ec_free(ec);
1828         return ret;
1829 }
1830
1831 #ifdef CONFIG_PM_SLEEP
1832 static int acpi_ec_suspend_noirq(struct device *dev)
1833 {
1834         struct acpi_ec *ec =
1835                 acpi_driver_data(to_acpi_device(dev));
1836
1837         acpi_ec_enter_noirq(ec);
1838         return 0;
1839 }
1840
1841 static int acpi_ec_resume_noirq(struct device *dev)
1842 {
1843         struct acpi_ec *ec =
1844                 acpi_driver_data(to_acpi_device(dev));
1845
1846         acpi_ec_leave_noirq(ec);
1847         return 0;
1848 }
1849
1850 static int acpi_ec_suspend(struct device *dev)
1851 {
1852         struct acpi_ec *ec =
1853                 acpi_driver_data(to_acpi_device(dev));
1854
1855         if (ec_freeze_events)
1856                 acpi_ec_disable_event(ec);
1857         return 0;
1858 }
1859
1860 static int acpi_ec_resume(struct device *dev)
1861 {
1862         struct acpi_ec *ec =
1863                 acpi_driver_data(to_acpi_device(dev));
1864
1865         acpi_ec_enable_event(ec);
1866         return 0;
1867 }
1868 #endif
1869
1870 static const struct dev_pm_ops acpi_ec_pm = {
1871         SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq)
1872         SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
1873 };
1874
1875 static int param_set_event_clearing(const char *val, struct kernel_param *kp)
1876 {
1877         int result = 0;
1878
1879         if (!strncmp(val, "status", sizeof("status") - 1)) {
1880                 ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1881                 pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
1882         } else if (!strncmp(val, "query", sizeof("query") - 1)) {
1883                 ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
1884                 pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
1885         } else if (!strncmp(val, "event", sizeof("event") - 1)) {
1886                 ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
1887                 pr_info("Assuming SCI_EVT clearing on event reads\n");
1888         } else
1889                 result = -EINVAL;
1890         return result;
1891 }
1892
1893 static int param_get_event_clearing(char *buffer, struct kernel_param *kp)
1894 {
1895         switch (ec_event_clearing) {
1896         case ACPI_EC_EVT_TIMING_STATUS:
1897                 return sprintf(buffer, "status");
1898         case ACPI_EC_EVT_TIMING_QUERY:
1899                 return sprintf(buffer, "query");
1900         case ACPI_EC_EVT_TIMING_EVENT:
1901                 return sprintf(buffer, "event");
1902         default:
1903                 return sprintf(buffer, "invalid");
1904         }
1905         return 0;
1906 }
1907
1908 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
1909                   NULL, 0644);
1910 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
1911
1912 static struct acpi_driver acpi_ec_driver = {
1913         .name = "ec",
1914         .class = ACPI_EC_CLASS,
1915         .ids = ec_device_ids,
1916         .ops = {
1917                 .add = acpi_ec_add,
1918                 .remove = acpi_ec_remove,
1919                 },
1920         .drv.pm = &acpi_ec_pm,
1921 };
1922
1923 static inline int acpi_ec_query_init(void)
1924 {
1925         if (!ec_query_wq) {
1926                 ec_query_wq = alloc_workqueue("kec_query", 0,
1927                                               ec_max_queries);
1928                 if (!ec_query_wq)
1929                         return -ENODEV;
1930         }
1931         return 0;
1932 }
1933
1934 static inline void acpi_ec_query_exit(void)
1935 {
1936         if (ec_query_wq) {
1937                 destroy_workqueue(ec_query_wq);
1938                 ec_query_wq = NULL;
1939         }
1940 }
1941
1942 int __init acpi_ec_init(void)
1943 {
1944         int result;
1945
1946         /* register workqueue for _Qxx evaluations */
1947         result = acpi_ec_query_init();
1948         if (result)
1949                 goto err_exit;
1950         /* Now register the driver for the EC */
1951         result = acpi_bus_register_driver(&acpi_ec_driver);
1952         if (result)
1953                 goto err_exit;
1954
1955 err_exit:
1956         if (result)
1957                 acpi_ec_query_exit();
1958         return result;
1959 }
1960
1961 /* EC driver currently not unloadable */
1962 #if 0
1963 static void __exit acpi_ec_exit(void)
1964 {
1965
1966         acpi_bus_unregister_driver(&acpi_ec_driver);
1967         acpi_ec_query_exit();
1968 }
1969 #endif  /* 0 */