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 = false;
 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_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
 192 static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
 193 static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
 194
 195 /* --------------------------------------------------------------------------
 196  *                           Logging/Debugging
 197  * -------------------------------------------------------------------------- */
 198
 199 /*
 200  * Splitters used by the developers to track the boundary of the EC
 201  * handling processes.
 202  */
 203 #ifdef DEBUG
 204 #define EC_DBG_SEP      " "
 205 #define EC_DBG_DRV      "+++++"
 206 #define EC_DBG_STM      "====="
 207 #define EC_DBG_REQ      "*****"
 208 #define EC_DBG_EVT      "#####"
 209 #else
 210 #define EC_DBG_SEP      ""
 211 #define EC_DBG_DRV
 212 #define EC_DBG_STM
 213 #define EC_DBG_REQ
 214 #define EC_DBG_EVT
 215 #endif
 216
 217 #define ec_log_raw(fmt, ...) \
 218         pr_info(fmt "\n", ##__VA_ARGS__)
 219 #define ec_dbg_raw(fmt, ...) \
 220         pr_debug(fmt "\n", ##__VA_ARGS__)
 221 #define ec_log(filter, fmt, ...) \
 222         ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
 223 #define ec_dbg(filter, fmt, ...) \
 224         ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
 225
 226 #define ec_log_drv(fmt, ...) \
 227         ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
 228 #define ec_dbg_drv(fmt, ...) \
 229         ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
 230 #define ec_dbg_stm(fmt, ...) \
 231         ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
 232 #define ec_dbg_req(fmt, ...) \
 233         ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
 234 #define ec_dbg_evt(fmt, ...) \
 235         ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
 236 #define ec_dbg_ref(ec, fmt, ...) \
 237         ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
 238
 239 /* --------------------------------------------------------------------------
 240  *                           Device Flags
 241  * -------------------------------------------------------------------------- */
 242
 243 static bool acpi_ec_started(struct acpi_ec *ec)
 244 {
 245         return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
 246                !test_bit(EC_FLAGS_STOPPED, &ec->flags);
 247 }
 248
 249 static bool acpi_ec_event_enabled(struct acpi_ec *ec)
 250 {
 251         /*
 252          * There is an OSPM early stage logic. During the early stages
 253          * (boot/resume), OSPMs shouldn't enable the event handling, only
 254          * the EC transactions are allowed to be performed.
 255          */
 256         if (!test_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 257                 return false;
 258         /*
 259          * However, disabling the event handling is experimental for late
 260          * stage (suspend), and is controlled by the boot parameter of
 261          * "ec_freeze_events":
 262          * 1. true:  The EC event handling is disabled before entering
 263          *           the noirq stage.
 264          * 2. false: The EC event handling is automatically disabled as
 265          *           soon as the EC driver is stopped.
 266          */
 267         if (ec_freeze_events)
 268                 return acpi_ec_started(ec);
 269         else
 270                 return test_bit(EC_FLAGS_STARTED, &ec->flags);
 271 }
 272
 273 static bool acpi_ec_flushed(struct acpi_ec *ec)
 274 {
 275         return ec->reference_count == 1;
 276 }
 277
 278 /* --------------------------------------------------------------------------
 279  *                           EC Registers
 280  * -------------------------------------------------------------------------- */
 281
 282 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
 283 {
 284         u8 x = inb(ec->command_addr);
 285
 286         ec_dbg_raw("EC_SC(R) = 0x%2.2x "
 287                    "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
 288                    x,
 289                    !!(x & ACPI_EC_FLAG_SCI),
 290                    !!(x & ACPI_EC_FLAG_BURST),
 291                    !!(x & ACPI_EC_FLAG_CMD),
 292                    !!(x & ACPI_EC_FLAG_IBF),
 293                    !!(x & ACPI_EC_FLAG_OBF));
 294         return x;
 295 }
 296
 297 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
 298 {
 299         u8 x = inb(ec->data_addr);
 300
 301         ec->timestamp = jiffies;
 302         ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
 303         return x;
 304 }
 305
 306 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
 307 {
 308         ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
 309         outb(command, ec->command_addr);
 310         ec->timestamp = jiffies;
 311 }
 312
 313 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
 314 {
 315         ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
 316         outb(data, ec->data_addr);
 317         ec->timestamp = jiffies;
 318 }
 319
 320 #ifdef DEBUG
 321 static const char *acpi_ec_cmd_string(u8 cmd)
 322 {
 323         switch (cmd) {
 324         case 0x80:
 325                 return "RD_EC";
 326         case 0x81:
 327                 return "WR_EC";
 328         case 0x82:
 329                 return "BE_EC";
 330         case 0x83:
 331                 return "BD_EC";
 332         case 0x84:
 333                 return "QR_EC";
 334         }
 335         return "UNKNOWN";
 336 }
 337 #else
 338 #define acpi_ec_cmd_string(cmd)         "UNDEF"
 339 #endif
 340
 341 /* --------------------------------------------------------------------------
 342  *                           GPE Registers
 343  * -------------------------------------------------------------------------- */
 344
 345 static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec)
 346 {
 347         acpi_event_status gpe_status = 0;
 348
 349         (void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
 350         return (gpe_status & ACPI_EVENT_FLAG_STATUS_SET) ? true : false;
 351 }
 352
 353 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
 354 {
 355         if (open)
 356                 acpi_enable_gpe(NULL, ec->gpe);
 357         else {
 358                 BUG_ON(ec->reference_count < 1);
 359                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
 360         }
 361         if (acpi_ec_is_gpe_raised(ec)) {
 362                 /*
 363                  * On some platforms, EN=1 writes cannot trigger GPE. So
 364                  * software need to manually trigger a pseudo GPE event on
 365                  * EN=1 writes.
 366                  */
 367                 ec_dbg_raw("Polling quirk");
 368                 advance_transaction(ec);
 369         }
 370 }
 371
 372 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
 373 {
 374         if (close)
 375                 acpi_disable_gpe(NULL, ec->gpe);
 376         else {
 377                 BUG_ON(ec->reference_count < 1);
 378                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
 379         }
 380 }
 381
 382 static inline void acpi_ec_clear_gpe(struct acpi_ec *ec)
 383 {
 384         /*
 385          * GPE STS is a W1C register, which means:
 386          * 1. Software can clear it without worrying about clearing other
 387          *    GPEs' STS bits when the hardware sets them in parallel.
 388          * 2. As long as software can ensure only clearing it when it is
 389          *    set, hardware won't set it in parallel.
 390          * So software can clear GPE in any contexts.
 391          * Warning: do not move the check into advance_transaction() as the
 392          * EC commands will be sent without GPE raised.
 393          */
 394         if (!acpi_ec_is_gpe_raised(ec))
 395                 return;
 396         acpi_clear_gpe(NULL, ec->gpe);
 397 }
 398
 399 /* --------------------------------------------------------------------------
 400  *                           Transaction Management
 401  * -------------------------------------------------------------------------- */
 402
 403 static void acpi_ec_submit_request(struct acpi_ec *ec)
 404 {
 405         ec->reference_count++;
 406         if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags) &&
 407             ec->reference_count == 1)
 408                 acpi_ec_enable_gpe(ec, true);
 409 }
 410
 411 static void acpi_ec_complete_request(struct acpi_ec *ec)
 412 {
 413         bool flushed = false;
 414
 415         ec->reference_count--;
 416         if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags) &&
 417             ec->reference_count == 0)
 418                 acpi_ec_disable_gpe(ec, true);
 419         flushed = acpi_ec_flushed(ec);
 420         if (flushed)
 421                 wake_up(&ec->wait);
 422 }
 423
 424 static void acpi_ec_set_storm(struct acpi_ec *ec, u8 flag)
 425 {
 426         if (!test_bit(flag, &ec->flags)) {
 427                 acpi_ec_disable_gpe(ec, false);
 428                 ec_dbg_drv("Polling enabled");
 429                 set_bit(flag, &ec->flags);
 430         }
 431 }
 432
 433 static void acpi_ec_clear_storm(struct acpi_ec *ec, u8 flag)
 434 {
 435         if (test_bit(flag, &ec->flags)) {
 436                 clear_bit(flag, &ec->flags);
 437                 acpi_ec_enable_gpe(ec, false);
 438                 ec_dbg_drv("Polling disabled");
 439         }
 440 }
 441
 442 /*
 443  * acpi_ec_submit_flushable_request() - Increase the reference count unless
 444  *                                      the flush operation is not in
 445  *                                      progress
 446  * @ec: the EC device
 447  *
 448  * This function must be used before taking a new action that should hold
 449  * the reference count.  If this function returns false, then the action
 450  * must be discarded or it will prevent the flush operation from being
 451  * completed.
 452  */
 453 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
 454 {
 455         if (!acpi_ec_started(ec))
 456                 return false;
 457         acpi_ec_submit_request(ec);
 458         return true;
 459 }
 460
 461 static void acpi_ec_submit_query(struct acpi_ec *ec)
 462 {
 463         if (acpi_ec_event_enabled(ec) &&
 464             !test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
 465                 ec_dbg_evt("Command(%s) submitted/blocked",
 466                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 467                 ec->nr_pending_queries++;
 468                 schedule_work(&ec->work);
 469         }
 470 }
 471
 472 static void acpi_ec_complete_query(struct acpi_ec *ec)
 473 {
 474         if (test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
 475                 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         }
 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         /*
 486          * Unconditionally invoke this once after enabling the event
 487          * handling mechanism to detect the pending events.
 488          */
 489         advance_transaction(ec);
 490 }
 491
 492 static inline void __acpi_ec_disable_event(struct acpi_ec *ec)
 493 {
 494         if (test_and_clear_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 495                 ec_log_drv("event blocked");
 496 }
 497
 498 /*
 499  * Process _Q events that might have accumulated in the EC.
 500  * Run with locked ec mutex.
 501  */
 502 static void acpi_ec_clear(struct acpi_ec *ec)
 503 {
 504         int i, status;
 505         u8 value = 0;
 506
 507         for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
 508                 status = acpi_ec_query(ec, &value);
 509                 if (status || !value)
 510                         break;
 511         }
 512         if (unlikely(i == ACPI_EC_CLEAR_MAX))
 513                 pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
 514         else
 515                 pr_info("%d stale EC events cleared\n", i);
 516 }
 517
 518 static void acpi_ec_enable_event(struct acpi_ec *ec)
 519 {
 520         unsigned long flags;
 521
 522         spin_lock_irqsave(&ec->lock, flags);
 523         if (acpi_ec_started(ec))
 524                 __acpi_ec_enable_event(ec);
 525         spin_unlock_irqrestore(&ec->lock, flags);
 526
 527         /* Drain additional events if hardware requires that */
 528         if (EC_FLAGS_CLEAR_ON_RESUME)
 529                 acpi_ec_clear(ec);
 530 }
 531
 532 #ifdef CONFIG_PM_SLEEP
 533 static bool acpi_ec_query_flushed(struct acpi_ec *ec)
 534 {
 535         bool flushed;
 536         unsigned long flags;
 537
 538         spin_lock_irqsave(&ec->lock, flags);
 539         flushed = !ec->nr_pending_queries;
 540         spin_unlock_irqrestore(&ec->lock, flags);
 541         return flushed;
 542 }
 543
 544 static void __acpi_ec_flush_event(struct acpi_ec *ec)
 545 {
 546         /*
 547          * When ec_freeze_events is true, we need to flush events in
 548          * the proper position before entering the noirq stage.
 549          */
 550         wait_event(ec->wait, acpi_ec_query_flushed(ec));
 551         if (ec_query_wq)
 552                 flush_workqueue(ec_query_wq);
 553 }
 554
 555 static void acpi_ec_disable_event(struct acpi_ec *ec)
 556 {
 557         unsigned long flags;
 558
 559         spin_lock_irqsave(&ec->lock, flags);
 560         __acpi_ec_disable_event(ec);
 561         spin_unlock_irqrestore(&ec->lock, flags);
 562         __acpi_ec_flush_event(ec);
 563 }
 564 #endif /* CONFIG_PM_SLEEP */
 565
 566 static bool acpi_ec_guard_event(struct acpi_ec *ec)
 567 {
 568         bool guarded = true;
 569         unsigned long flags;
 570
 571         spin_lock_irqsave(&ec->lock, flags);
 572         /*
 573          * If firmware SCI_EVT clearing timing is "event", we actually
 574          * don't know when the SCI_EVT will be cleared by firmware after
 575          * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
 576          * acceptable period.
 577          *
 578          * The guarding period begins when EC_FLAGS_QUERY_PENDING is
 579          * flagged, which means SCI_EVT check has just been performed.
 580          * But if the current transaction is ACPI_EC_COMMAND_QUERY, the
 581          * guarding should have already been performed (via
 582          * EC_FLAGS_QUERY_GUARDING) and should not be applied so that the
 583          * ACPI_EC_COMMAND_QUERY transaction can be transitioned into
 584          * ACPI_EC_COMMAND_POLL state immediately.
 585          */
 586         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
 587             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY ||
 588             !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) ||
 589             (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY))
 590                 guarded = false;
 591         spin_unlock_irqrestore(&ec->lock, flags);
 592         return guarded;
 593 }
 594
 595 static int ec_transaction_polled(struct acpi_ec *ec)
 596 {
 597         unsigned long flags;
 598         int ret = 0;
 599
 600         spin_lock_irqsave(&ec->lock, flags);
 601         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
 602                 ret = 1;
 603         spin_unlock_irqrestore(&ec->lock, flags);
 604         return ret;
 605 }
 606
 607 static int ec_transaction_completed(struct acpi_ec *ec)
 608 {
 609         unsigned long flags;
 610         int ret = 0;
 611
 612         spin_lock_irqsave(&ec->lock, flags);
 613         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
 614                 ret = 1;
 615         spin_unlock_irqrestore(&ec->lock, flags);
 616         return ret;
 617 }
 618
 619 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
 620 {
 621         ec->curr->flags |= flag;
 622         if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
 623                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS &&
 624                     flag == ACPI_EC_COMMAND_POLL)
 625                         acpi_ec_complete_query(ec);
 626                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY &&
 627                     flag == ACPI_EC_COMMAND_COMPLETE)
 628                         acpi_ec_complete_query(ec);
 629                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 630                     flag == ACPI_EC_COMMAND_COMPLETE)
 631                         set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
 632         }
 633 }
 634
 635 static void advance_transaction(struct acpi_ec *ec)
 636 {
 637         struct transaction *t;
 638         u8 status;
 639         bool wakeup = false;
 640
 641         ec_dbg_stm("%s (%d)", in_interrupt() ? "IRQ" : "TASK",
 642                    smp_processor_id());
 643         /*
 644          * By always clearing STS before handling all indications, we can
 645          * ensure a hardware STS 0->1 change after this clearing can always
 646          * trigger a GPE interrupt.
 647          */
 648         acpi_ec_clear_gpe(ec);
 649         status = acpi_ec_read_status(ec);
 650         t = ec->curr;
 651         /*
 652          * Another IRQ or a guarded polling mode advancement is detected,
 653          * the next QR_EC submission is then allowed.
 654          */
 655         if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
 656                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 657                     (!ec->nr_pending_queries ||
 658                      test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) {
 659                         clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
 660                         acpi_ec_complete_query(ec);
 661                 }
 662         }
 663         if (!t)
 664                 goto err;
 665         if (t->flags & ACPI_EC_COMMAND_POLL) {
 666                 if (t->wlen > t->wi) {
 667                         if ((status & ACPI_EC_FLAG_IBF) == 0)
 668                                 acpi_ec_write_data(ec, t->wdata[t->wi++]);
 669                         else
 670                                 goto err;
 671                 } else if (t->rlen > t->ri) {
 672                         if ((status & ACPI_EC_FLAG_OBF) == 1) {
 673                                 t->rdata[t->ri++] = acpi_ec_read_data(ec);
 674                                 if (t->rlen == t->ri) {
 675                                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 676                                         if (t->command == ACPI_EC_COMMAND_QUERY)
 677                                                 ec_dbg_evt("Command(%s) completed by hardware",
 678                                                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 679                                         wakeup = true;
 680                                 }
 681                         } else
 682                                 goto err;
 683                 } else if (t->wlen == t->wi &&
 684                            (status & ACPI_EC_FLAG_IBF) == 0) {
 685                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 686                         wakeup = true;
 687                 }
 688                 goto out;
 689         } else {
 690                 if (EC_FLAGS_QUERY_HANDSHAKE &&
 691                     !(status & ACPI_EC_FLAG_SCI) &&
 692                     (t->command == ACPI_EC_COMMAND_QUERY)) {
 693                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
 694                         t->rdata[t->ri++] = 0x00;
 695                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 696                         ec_dbg_evt("Command(%s) completed by software",
 697                                    acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 698                         wakeup = true;
 699                 } else if ((status & ACPI_EC_FLAG_IBF) == 0) {
 700                         acpi_ec_write_cmd(ec, t->command);
 701                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
 702                 } else
 703                         goto err;
 704                 goto out;
 705         }
 706 err:
 707         /*
 708          * If SCI bit is set, then don't think it's a false IRQ
 709          * otherwise will take a not handled IRQ as a false one.
 710          */
 711         if (!(status & ACPI_EC_FLAG_SCI)) {
 712                 if (in_interrupt() && t) {
 713                         if (t->irq_count < ec_storm_threshold)
 714                                 ++t->irq_count;
 715                         /* Allow triggering on 0 threshold */
 716                         if (t->irq_count == ec_storm_threshold)
 717                                 acpi_ec_set_storm(ec, EC_FLAGS_COMMAND_STORM);
 718                 }
 719         }
 720 out:
 721         if (status & ACPI_EC_FLAG_SCI)
 722                 acpi_ec_submit_query(ec);
 723         if (wakeup && in_interrupt())
 724                 wake_up(&ec->wait);
 725 }
 726
 727 static void start_transaction(struct acpi_ec *ec)
 728 {
 729         ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
 730         ec->curr->flags = 0;
 731 }
 732
 733 static int ec_guard(struct acpi_ec *ec)
 734 {
 735         unsigned long guard = usecs_to_jiffies(ec->polling_guard);
 736         unsigned long timeout = ec->timestamp + guard;
 737
 738         /* Ensure guarding period before polling EC status */
 739         do {
 740                 if (ec->busy_polling) {
 741                         /* Perform busy polling */
 742                         if (ec_transaction_completed(ec))
 743                                 return 0;
 744                         udelay(jiffies_to_usecs(guard));
 745                 } else {
 746                         /*
 747                          * Perform wait polling
 748                          * 1. Wait the transaction to be completed by the
 749                          *    GPE handler after the transaction enters
 750                          *    ACPI_EC_COMMAND_POLL state.
 751                          * 2. A special guarding logic is also required
 752                          *    for event clearing mode "event" before the
 753                          *    transaction enters ACPI_EC_COMMAND_POLL
 754                          *    state.
 755                          */
 756                         if (!ec_transaction_polled(ec) &&
 757                             !acpi_ec_guard_event(ec))
 758                                 break;
 759                         if (wait_event_timeout(ec->wait,
 760                                                ec_transaction_completed(ec),
 761                                                guard))
 762                                 return 0;
 763                 }
 764         } while (time_before(jiffies, timeout));
 765         return -ETIME;
 766 }
 767
 768 static int ec_poll(struct acpi_ec *ec)
 769 {
 770         unsigned long flags;
 771         int repeat = 5; /* number of command restarts */
 772
 773         while (repeat--) {
 774                 unsigned long delay = jiffies +
 775                         msecs_to_jiffies(ec_delay);
 776                 do {
 777                         if (!ec_guard(ec))
 778                                 return 0;
 779                         spin_lock_irqsave(&ec->lock, flags);
 780                         advance_transaction(ec);
 781                         spin_unlock_irqrestore(&ec->lock, flags);
 782                 } while (time_before(jiffies, delay));
 783                 pr_debug("controller reset, restart transaction\n");
 784                 spin_lock_irqsave(&ec->lock, flags);
 785                 start_transaction(ec);
 786                 spin_unlock_irqrestore(&ec->lock, flags);
 787         }
 788         return -ETIME;
 789 }
 790
 791 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
 792                                         struct transaction *t)
 793 {
 794         unsigned long tmp;
 795         int ret = 0;
 796
 797         /* start transaction */
 798         spin_lock_irqsave(&ec->lock, tmp);
 799         /* Enable GPE for command processing (IBF=0/OBF=1) */
 800         if (!acpi_ec_submit_flushable_request(ec)) {
 801                 ret = -EINVAL;
 802                 goto unlock;
 803         }
 804         ec_dbg_ref(ec, "Increase command");
 805         /* following two actions should be kept atomic */
 806         ec->curr = t;
 807         ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
 808         start_transaction(ec);
 809         spin_unlock_irqrestore(&ec->lock, tmp);
 810
 811         ret = ec_poll(ec);
 812
 813         spin_lock_irqsave(&ec->lock, tmp);
 814         if (t->irq_count == ec_storm_threshold)
 815                 acpi_ec_clear_storm(ec, EC_FLAGS_COMMAND_STORM);
 816         ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
 817         ec->curr = NULL;
 818         /* Disable GPE for command processing (IBF=0/OBF=1) */
 819         acpi_ec_complete_request(ec);
 820         ec_dbg_ref(ec, "Decrease command");
 821 unlock:
 822         spin_unlock_irqrestore(&ec->lock, tmp);
 823         return ret;
 824 }
 825
 826 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
 827 {
 828         int status;
 829         u32 glk;
 830
 831         if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
 832                 return -EINVAL;
 833         if (t->rdata)
 834                 memset(t->rdata, 0, t->rlen);
 835
 836         mutex_lock(&ec->mutex);
 837         if (ec->global_lock) {
 838                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
 839                 if (ACPI_FAILURE(status)) {
 840                         status = -ENODEV;
 841                         goto unlock;
 842                 }
 843         }
 844
 845         status = acpi_ec_transaction_unlocked(ec, t);
 846
 847         if (ec->global_lock)
 848                 acpi_release_global_lock(glk);
 849 unlock:
 850         mutex_unlock(&ec->mutex);
 851         return status;
 852 }
 853
 854 static int acpi_ec_burst_enable(struct acpi_ec *ec)
 855 {
 856         u8 d;
 857         struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
 858                                 .wdata = NULL, .rdata = &d,
 859                                 .wlen = 0, .rlen = 1};
 860
 861         return acpi_ec_transaction(ec, &t);
 862 }
 863
 864 static int acpi_ec_burst_disable(struct acpi_ec *ec)
 865 {
 866         struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
 867                                 .wdata = NULL, .rdata = NULL,
 868                                 .wlen = 0, .rlen = 0};
 869
 870         return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
 871                                 acpi_ec_transaction(ec, &t) : 0;
 872 }
 873
 874 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
 875 {
 876         int result;
 877         u8 d;
 878         struct transaction t = {.command = ACPI_EC_COMMAND_READ,
 879                                 .wdata = &address, .rdata = &d,
 880                                 .wlen = 1, .rlen = 1};
 881
 882         result = acpi_ec_transaction(ec, &t);
 883         *data = d;
 884         return result;
 885 }
 886
 887 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
 888 {
 889         u8 wdata[2] = { address, data };
 890         struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
 891                                 .wdata = wdata, .rdata = NULL,
 892                                 .wlen = 2, .rlen = 0};
 893
 894         return acpi_ec_transaction(ec, &t);
 895 }
 896
 897 int ec_read(u8 addr, u8 *val)
 898 {
 899         int err;
 900         u8 temp_data;
 901
 902         if (!first_ec)
 903                 return -ENODEV;
 904
 905         err = acpi_ec_read(first_ec, addr, &temp_data);
 906
 907         if (!err) {
 908                 *val = temp_data;
 909                 return 0;
 910         }
 911         return err;
 912 }
 913 EXPORT_SYMBOL(ec_read);
 914
 915 int ec_write(u8 addr, u8 val)
 916 {
 917         int err;
 918
 919         if (!first_ec)
 920                 return -ENODEV;
 921
 922         err = acpi_ec_write(first_ec, addr, val);
 923
 924         return err;
 925 }
 926 EXPORT_SYMBOL(ec_write);
 927
 928 int ec_transaction(u8 command,
 929                    const u8 *wdata, unsigned wdata_len,
 930                    u8 *rdata, unsigned rdata_len)
 931 {
 932         struct transaction t = {.command = command,
 933                                 .wdata = wdata, .rdata = rdata,
 934                                 .wlen = wdata_len, .rlen = rdata_len};
 935
 936         if (!first_ec)
 937                 return -ENODEV;
 938
 939         return acpi_ec_transaction(first_ec, &t);
 940 }
 941 EXPORT_SYMBOL(ec_transaction);
 942
 943 /* Get the handle to the EC device */
 944 acpi_handle ec_get_handle(void)
 945 {
 946         if (!first_ec)
 947                 return NULL;
 948         return first_ec->handle;
 949 }
 950 EXPORT_SYMBOL(ec_get_handle);
 951
 952 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
 953 {
 954         unsigned long flags;
 955
 956         spin_lock_irqsave(&ec->lock, flags);
 957         if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
 958                 ec_dbg_drv("Starting EC");
 959                 /* Enable GPE for event processing (SCI_EVT=1) */
 960                 if (!resuming) {
 961                         acpi_ec_submit_request(ec);
 962                         ec_dbg_ref(ec, "Increase driver");
 963                 }
 964                 ec_log_drv("EC started");
 965         }
 966         spin_unlock_irqrestore(&ec->lock, flags);
 967 }
 968
 969 static bool acpi_ec_stopped(struct acpi_ec *ec)
 970 {
 971         unsigned long flags;
 972         bool flushed;
 973
 974         spin_lock_irqsave(&ec->lock, flags);
 975         flushed = acpi_ec_flushed(ec);
 976         spin_unlock_irqrestore(&ec->lock, flags);
 977         return flushed;
 978 }
 979
 980 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
 981 {
 982         unsigned long flags;
 983
 984         spin_lock_irqsave(&ec->lock, flags);
 985         if (acpi_ec_started(ec)) {
 986                 ec_dbg_drv("Stopping EC");
 987                 set_bit(EC_FLAGS_STOPPED, &ec->flags);
 988                 spin_unlock_irqrestore(&ec->lock, flags);
 989                 wait_event(ec->wait, acpi_ec_stopped(ec));
 990                 spin_lock_irqsave(&ec->lock, flags);
 991                 /* Disable GPE for event processing (SCI_EVT=1) */
 992                 if (!suspending) {
 993                         acpi_ec_complete_request(ec);
 994                         ec_dbg_ref(ec, "Decrease driver");
 995                 } else if (!ec_freeze_events)
 996                         __acpi_ec_disable_event(ec);
 997                 clear_bit(EC_FLAGS_STARTED, &ec->flags);
 998                 clear_bit(EC_FLAGS_STOPPED, &ec->flags);
 999                 ec_log_drv("EC stopped");
1000         }
1001         spin_unlock_irqrestore(&ec->lock, flags);
1002 }
1003
1004 static void acpi_ec_enter_noirq(struct acpi_ec *ec)
1005 {
1006         unsigned long flags;
1007
1008         spin_lock_irqsave(&ec->lock, flags);
1009         ec->busy_polling = true;
1010         ec->polling_guard = 0;
1011         ec_log_drv("interrupt blocked");
1012         spin_unlock_irqrestore(&ec->lock, flags);
1013 }
1014
1015 static void acpi_ec_leave_noirq(struct acpi_ec *ec)
1016 {
1017         unsigned long flags;
1018
1019         spin_lock_irqsave(&ec->lock, flags);
1020         ec->busy_polling = ec_busy_polling;
1021         ec->polling_guard = ec_polling_guard;
1022         ec_log_drv("interrupt unblocked");
1023         spin_unlock_irqrestore(&ec->lock, flags);
1024 }
1025
1026 void acpi_ec_block_transactions(void)
1027 {
1028         struct acpi_ec *ec = first_ec;
1029
1030         if (!ec)
1031                 return;
1032
1033         mutex_lock(&ec->mutex);
1034         /* Prevent transactions from being carried out */
1035         acpi_ec_stop(ec, true);
1036         mutex_unlock(&ec->mutex);
1037 }
1038
1039 void acpi_ec_unblock_transactions(void)
1040 {
1041         /*
1042          * Allow transactions to happen again (this function is called from
1043          * atomic context during wakeup, so we don't need to acquire the mutex).
1044          */
1045         if (first_ec)
1046                 acpi_ec_start(first_ec, true);
1047 }
1048
1049 /* --------------------------------------------------------------------------
1050                                 Event Management
1051    -------------------------------------------------------------------------- */
1052 static struct acpi_ec_query_handler *
1053 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
1054 {
1055         struct acpi_ec_query_handler *handler;
1056
1057         mutex_lock(&ec->mutex);
1058         list_for_each_entry(handler, &ec->list, node) {
1059                 if (value == handler->query_bit) {
1060                         kref_get(&handler->kref);
1061                         mutex_unlock(&ec->mutex);
1062                         return handler;
1063                 }
1064         }
1065         mutex_unlock(&ec->mutex);
1066         return NULL;
1067 }
1068
1069 static void acpi_ec_query_handler_release(struct kref *kref)
1070 {
1071         struct acpi_ec_query_handler *handler =
1072                 container_of(kref, struct acpi_ec_query_handler, kref);
1073
1074         kfree(handler);
1075 }
1076
1077 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
1078 {
1079         kref_put(&handler->kref, acpi_ec_query_handler_release);
1080 }
1081
1082 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
1083                               acpi_handle handle, acpi_ec_query_func func,
1084                               void *data)
1085 {
1086         struct acpi_ec_query_handler *handler =
1087             kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
1088
1089         if (!handler)
1090                 return -ENOMEM;
1091
1092         handler->query_bit = query_bit;
1093         handler->handle = handle;
1094         handler->func = func;
1095         handler->data = data;
1096         mutex_lock(&ec->mutex);
1097         kref_init(&handler->kref);
1098         list_add(&handler->node, &ec->list);
1099         mutex_unlock(&ec->mutex);
1100         return 0;
1101 }
1102 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1103
1104 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1105                                           bool remove_all, u8 query_bit)
1106 {
1107         struct acpi_ec_query_handler *handler, *tmp;
1108         LIST_HEAD(free_list);
1109
1110         mutex_lock(&ec->mutex);
1111         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1112                 if (remove_all || query_bit == handler->query_bit) {
1113                         list_del_init(&handler->node);
1114                         list_add(&handler->node, &free_list);
1115                 }
1116         }
1117         mutex_unlock(&ec->mutex);
1118         list_for_each_entry_safe(handler, tmp, &free_list, node)
1119                 acpi_ec_put_query_handler(handler);
1120 }
1121
1122 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1123 {
1124         acpi_ec_remove_query_handlers(ec, false, query_bit);
1125 }
1126 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1127
1128 static struct acpi_ec_query *acpi_ec_create_query(u8 *pval)
1129 {
1130         struct acpi_ec_query *q;
1131         struct transaction *t;
1132
1133         q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1134         if (!q)
1135                 return NULL;
1136         INIT_WORK(&q->work, acpi_ec_event_processor);
1137         t = &q->transaction;
1138         t->command = ACPI_EC_COMMAND_QUERY;
1139         t->rdata = pval;
1140         t->rlen = 1;
1141         return q;
1142 }
1143
1144 static void acpi_ec_delete_query(struct acpi_ec_query *q)
1145 {
1146         if (q) {
1147                 if (q->handler)
1148                         acpi_ec_put_query_handler(q->handler);
1149                 kfree(q);
1150         }
1151 }
1152
1153 static void acpi_ec_event_processor(struct work_struct *work)
1154 {
1155         struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1156         struct acpi_ec_query_handler *handler = q->handler;
1157
1158         ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1159         if (handler->func)
1160                 handler->func(handler->data);
1161         else if (handler->handle)
1162                 acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1163         ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1164         acpi_ec_delete_query(q);
1165 }
1166
1167 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
1168 {
1169         u8 value = 0;
1170         int result;
1171         struct acpi_ec_query *q;
1172
1173         q = acpi_ec_create_query(&value);
1174         if (!q)
1175                 return -ENOMEM;
1176
1177         /*
1178          * Query the EC to find out which _Qxx method we need to evaluate.
1179          * Note that successful completion of the query causes the ACPI_EC_SCI
1180          * bit to be cleared (and thus clearing the interrupt source).
1181          */
1182         result = acpi_ec_transaction(ec, &q->transaction);
1183         if (!value)
1184                 result = -ENODATA;
1185         if (result)
1186                 goto err_exit;
1187
1188         q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1189         if (!q->handler) {
1190                 result = -ENODATA;
1191                 goto err_exit;
1192         }
1193
1194         /*
1195          * It is reported that _Qxx are evaluated in a parallel way on
1196          * Windows:
1197          * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1198          *
1199          * Put this log entry before schedule_work() in order to make
1200          * it appearing before any other log entries occurred during the
1201          * work queue execution.
1202          */
1203         ec_dbg_evt("Query(0x%02x) scheduled", value);
1204         if (!queue_work(ec_query_wq, &q->work)) {
1205                 ec_dbg_evt("Query(0x%02x) overlapped", value);
1206                 result = -EBUSY;
1207         }
1208
1209 err_exit:
1210         if (result)
1211                 acpi_ec_delete_query(q);
1212         if (data)
1213                 *data = value;
1214         return result;
1215 }
1216
1217 static void acpi_ec_check_event(struct acpi_ec *ec)
1218 {
1219         unsigned long flags;
1220
1221         if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1222                 if (ec_guard(ec)) {
1223                         spin_lock_irqsave(&ec->lock, flags);
1224                         /*
1225                          * Take care of the SCI_EVT unless no one else is
1226                          * taking care of it.
1227                          */
1228                         if (!ec->curr)
1229                                 advance_transaction(ec);
1230                         spin_unlock_irqrestore(&ec->lock, flags);
1231                 }
1232         }
1233 }
1234
1235 static void acpi_ec_event_handler(struct work_struct *work)
1236 {
1237         unsigned long flags;
1238         struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1239
1240         ec_dbg_evt("Event started");
1241
1242         spin_lock_irqsave(&ec->lock, flags);
1243         while (ec->nr_pending_queries) {
1244                 spin_unlock_irqrestore(&ec->lock, flags);
1245                 (void)acpi_ec_query(ec, NULL);
1246                 spin_lock_irqsave(&ec->lock, flags);
1247                 ec->nr_pending_queries--;
1248                 /*
1249                  * Before exit, make sure that this work item can be
1250                  * scheduled again. There might be QR_EC failures, leaving
1251                  * EC_FLAGS_QUERY_PENDING uncleared and preventing this work
1252                  * item from being scheduled again.
1253                  */
1254                 if (!ec->nr_pending_queries) {
1255                         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
1256                             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY)
1257                                 acpi_ec_complete_query(ec);
1258                 }
1259         }
1260         spin_unlock_irqrestore(&ec->lock, flags);
1261
1262         ec_dbg_evt("Event stopped");
1263
1264         acpi_ec_check_event(ec);
1265 }
1266
1267 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1268         u32 gpe_number, void *data)
1269 {
1270         unsigned long flags;
1271         struct acpi_ec *ec = data;
1272
1273         spin_lock_irqsave(&ec->lock, flags);
1274         advance_transaction(ec);
1275         spin_unlock_irqrestore(&ec->lock, flags);
1276         return ACPI_INTERRUPT_HANDLED;
1277 }
1278
1279 /* --------------------------------------------------------------------------
1280  *                           Address Space Management
1281  * -------------------------------------------------------------------------- */
1282
1283 static acpi_status
1284 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1285                       u32 bits, u64 *value64,
1286                       void *handler_context, void *region_context)
1287 {
1288         struct acpi_ec *ec = handler_context;
1289         int result = 0, i, bytes = bits / 8;
1290         u8 *value = (u8 *)value64;
1291
1292         if ((address > 0xFF) || !value || !handler_context)
1293                 return AE_BAD_PARAMETER;
1294
1295         if (function != ACPI_READ && function != ACPI_WRITE)
1296                 return AE_BAD_PARAMETER;
1297
1298         if (ec->busy_polling || bits > 8)
1299                 acpi_ec_burst_enable(ec);
1300
1301         for (i = 0; i < bytes; ++i, ++address, ++value)
1302                 result = (function == ACPI_READ) ?
1303                         acpi_ec_read(ec, address, value) :
1304                         acpi_ec_write(ec, address, *value);
1305
1306         if (ec->busy_polling || bits > 8)
1307                 acpi_ec_burst_disable(ec);
1308
1309         switch (result) {
1310         case -EINVAL:
1311                 return AE_BAD_PARAMETER;
1312         case -ENODEV:
1313                 return AE_NOT_FOUND;
1314         case -ETIME:
1315                 return AE_TIME;
1316         default:
1317                 return AE_OK;
1318         }
1319 }
1320
1321 /* --------------------------------------------------------------------------
1322  *                             Driver Interface
1323  * -------------------------------------------------------------------------- */
1324
1325 static acpi_status
1326 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1327
1328 static void acpi_ec_free(struct acpi_ec *ec)
1329 {
1330         if (first_ec == ec)
1331                 first_ec = NULL;
1332         if (boot_ec == ec)
1333                 boot_ec = NULL;
1334         kfree(ec);
1335 }
1336
1337 static struct acpi_ec *acpi_ec_alloc(void)
1338 {
1339         struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1340
1341         if (!ec)
1342                 return NULL;
1343         mutex_init(&ec->mutex);
1344         init_waitqueue_head(&ec->wait);
1345         INIT_LIST_HEAD(&ec->list);
1346         spin_lock_init(&ec->lock);
1347         INIT_WORK(&ec->work, acpi_ec_event_handler);
1348         ec->timestamp = jiffies;
1349         ec->busy_polling = true;
1350         ec->polling_guard = 0;
1351         return ec;
1352 }
1353
1354 static acpi_status
1355 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1356                                void *context, void **return_value)
1357 {
1358         char node_name[5];
1359         struct acpi_buffer buffer = { sizeof(node_name), node_name };
1360         struct acpi_ec *ec = context;
1361         int value = 0;
1362         acpi_status status;
1363
1364         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1365
1366         if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1367                 acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1368         return AE_OK;
1369 }
1370
1371 static acpi_status
1372 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1373 {
1374         acpi_status status;
1375         unsigned long long tmp = 0;
1376         struct acpi_ec *ec = context;
1377
1378         /* clear addr values, ec_parse_io_ports depend on it */
1379         ec->command_addr = ec->data_addr = 0;
1380
1381         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1382                                      ec_parse_io_ports, ec);
1383         if (ACPI_FAILURE(status))
1384                 return status;
1385
1386         /* Get GPE bit assignment (EC events). */
1387         /* TODO: Add support for _GPE returning a package */
1388         status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1389         if (ACPI_FAILURE(status))
1390                 return status;
1391         ec->gpe = tmp;
1392         /* Use the global lock for all EC transactions? */
1393         tmp = 0;
1394         acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1395         ec->global_lock = tmp;
1396         ec->handle = handle;
1397         return AE_CTRL_TERMINATE;
1398 }
1399
1400 /*
1401  * Note: This function returns an error code only when the address space
1402  *       handler is not installed, which means "not able to handle
1403  *       transactions".
1404  */
1405 static int ec_install_handlers(struct acpi_ec *ec, bool handle_events)
1406 {
1407         acpi_status status;
1408
1409         acpi_ec_start(ec, false);
1410
1411         if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1412                 acpi_ec_enter_noirq(ec);
1413                 status = acpi_install_address_space_handler(ec->handle,
1414                                                             ACPI_ADR_SPACE_EC,
1415                                                             &acpi_ec_space_handler,
1416                                                             NULL, ec);
1417                 if (ACPI_FAILURE(status)) {
1418                         if (status == AE_NOT_FOUND) {
1419                                 /*
1420                                  * Maybe OS fails in evaluating the _REG
1421                                  * object. The AE_NOT_FOUND error will be
1422                                  * ignored and OS * continue to initialize
1423                                  * EC.
1424                                  */
1425                                 pr_err("Fail in evaluating the _REG object"
1426                                         " of EC device. Broken bios is suspected.\n");
1427                         } else {
1428                                 acpi_ec_stop(ec, false);
1429                                 return -ENODEV;
1430                         }
1431                 }
1432                 set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1433         }
1434
1435         if (!handle_events)
1436                 return 0;
1437
1438         if (!test_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags)) {
1439                 /* Find and register all query methods */
1440                 acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1441                                     acpi_ec_register_query_methods,
1442                                     NULL, ec, NULL);
1443                 set_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags);
1444         }
1445         if (!test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
1446                 status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1447                                           ACPI_GPE_EDGE_TRIGGERED,
1448                                           &acpi_ec_gpe_handler, ec);
1449                 /* This is not fatal as we can poll EC events */
1450                 if (ACPI_SUCCESS(status)) {
1451                         set_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
1452                         acpi_ec_leave_noirq(ec);
1453                         if (test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1454                             ec->reference_count >= 1)
1455                                 acpi_ec_enable_gpe(ec, true);
1456                 }
1457         }
1458         /* EC is fully operational, allow queries */
1459         acpi_ec_enable_event(ec);
1460
1461         return 0;
1462 }
1463
1464 static void ec_remove_handlers(struct acpi_ec *ec)
1465 {
1466         if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1467                 if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1468                                         ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1469                         pr_err("failed to remove space handler\n");
1470                 clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1471         }
1472
1473         /*
1474          * Stops handling the EC transactions after removing the operation
1475          * region handler. This is required because _REG(DISCONNECT)
1476          * invoked during the removal can result in new EC transactions.
1477          *
1478          * Flushes the EC requests and thus disables the GPE before
1479          * removing the GPE handler. This is required by the current ACPICA
1480          * GPE core. ACPICA GPE core will automatically disable a GPE when
1481          * it is indicated but there is no way to handle it. So the drivers
1482          * must disable the GPEs prior to removing the GPE handlers.
1483          */
1484         acpi_ec_stop(ec, false);
1485
1486         if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
1487                 if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1488                                         &acpi_ec_gpe_handler)))
1489                         pr_err("failed to remove gpe handler\n");
1490                 clear_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
1491         }
1492         if (test_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags)) {
1493                 acpi_ec_remove_query_handlers(ec, true, 0);
1494                 clear_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags);
1495         }
1496 }
1497
1498 static int acpi_ec_setup(struct acpi_ec *ec, bool handle_events)
1499 {
1500         int ret;
1501
1502         ret = ec_install_handlers(ec, handle_events);
1503         if (ret)
1504                 return ret;
1505
1506         /* First EC capable of handling transactions */
1507         if (!first_ec) {
1508                 first_ec = ec;
1509                 acpi_handle_info(first_ec->handle, "Used as first EC\n");
1510         }
1511
1512         acpi_handle_info(ec->handle,
1513                          "GPE=0x%x, EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n",
1514                          ec->gpe, ec->command_addr, ec->data_addr);
1515         return ret;
1516 }
1517
1518 static int acpi_config_boot_ec(struct acpi_ec *ec, acpi_handle handle,
1519                                bool handle_events, bool is_ecdt)
1520 {
1521         int ret;
1522
1523         /*
1524          * Changing the ACPI handle results in a re-configuration of the
1525          * boot EC. And if it happens after the namespace initialization,
1526          * it causes _REG evaluations.
1527          */
1528         if (boot_ec && boot_ec->handle != handle)
1529                 ec_remove_handlers(boot_ec);
1530
1531         /* Unset old boot EC */
1532         if (boot_ec != ec)
1533                 acpi_ec_free(boot_ec);
1534
1535         /*
1536          * ECDT device creation is split into acpi_ec_ecdt_probe() and
1537          * acpi_ec_ecdt_start(). This function takes care of completing the
1538          * ECDT parsing logic as the handle update should be performed
1539          * between the installation/uninstallation of the handlers.
1540          */
1541         if (ec->handle != handle)
1542                 ec->handle = handle;
1543
1544         ret = acpi_ec_setup(ec, handle_events);
1545         if (ret)
1546                 return ret;
1547
1548         /* Set new boot EC */
1549         if (!boot_ec) {
1550                 boot_ec = ec;
1551                 boot_ec_is_ecdt = is_ecdt;
1552         }
1553
1554         acpi_handle_info(boot_ec->handle,
1555                          "Used as boot %s EC to handle transactions%s\n",
1556                          is_ecdt ? "ECDT" : "DSDT",
1557                          handle_events ? " and events" : "");
1558         return ret;
1559 }
1560
1561 static bool acpi_ec_ecdt_get_handle(acpi_handle *phandle)
1562 {
1563         struct acpi_table_ecdt *ecdt_ptr;
1564         acpi_status status;
1565         acpi_handle handle;
1566
1567         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1568                                 (struct acpi_table_header **)&ecdt_ptr);
1569         if (ACPI_FAILURE(status))
1570                 return false;
1571
1572         status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
1573         if (ACPI_FAILURE(status))
1574                 return false;
1575
1576         *phandle = handle;
1577         return true;
1578 }
1579
1580 static bool acpi_is_boot_ec(struct acpi_ec *ec)
1581 {
1582         if (!boot_ec)
1583                 return false;
1584         if (ec->handle == boot_ec->handle &&
1585             ec->gpe == boot_ec->gpe &&
1586             ec->command_addr == boot_ec->command_addr &&
1587             ec->data_addr == boot_ec->data_addr)
1588                 return true;
1589         return false;
1590 }
1591
1592 static int acpi_ec_add(struct acpi_device *device)
1593 {
1594         struct acpi_ec *ec = NULL;
1595         int ret;
1596
1597         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1598         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1599
1600         ec = acpi_ec_alloc();
1601         if (!ec)
1602                 return -ENOMEM;
1603         if (ec_parse_device(device->handle, 0, ec, NULL) !=
1604                 AE_CTRL_TERMINATE) {
1605                         ret = -EINVAL;
1606                         goto err_alloc;
1607         }
1608
1609         if (acpi_is_boot_ec(ec)) {
1610                 boot_ec_is_ecdt = false;
1611                 acpi_handle_debug(ec->handle, "duplicated.\n");
1612                 acpi_ec_free(ec);
1613                 ec = boot_ec;
1614                 ret = acpi_config_boot_ec(ec, ec->handle, true, false);
1615         } else
1616                 ret = acpi_ec_setup(ec, true);
1617         if (ret)
1618                 goto err_query;
1619
1620         device->driver_data = ec;
1621
1622         ret = !!request_region(ec->data_addr, 1, "EC data");
1623         WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1624         ret = !!request_region(ec->command_addr, 1, "EC cmd");
1625         WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1626
1627         /* Reprobe devices depending on the EC */
1628         acpi_walk_dep_device_list(ec->handle);
1629         acpi_handle_debug(ec->handle, "enumerated.\n");
1630         return 0;
1631
1632 err_query:
1633         if (ec != boot_ec)
1634                 acpi_ec_remove_query_handlers(ec, true, 0);
1635 err_alloc:
1636         if (ec != boot_ec)
1637                 acpi_ec_free(ec);
1638         return ret;
1639 }
1640
1641 static int acpi_ec_remove(struct acpi_device *device)
1642 {
1643         struct acpi_ec *ec;
1644
1645         if (!device)
1646                 return -EINVAL;
1647
1648         ec = acpi_driver_data(device);
1649         release_region(ec->data_addr, 1);
1650         release_region(ec->command_addr, 1);
1651         device->driver_data = NULL;
1652         if (ec != boot_ec) {
1653                 ec_remove_handlers(ec);
1654                 acpi_ec_free(ec);
1655         }
1656         return 0;
1657 }
1658
1659 static acpi_status
1660 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1661 {
1662         struct acpi_ec *ec = context;
1663
1664         if (resource->type != ACPI_RESOURCE_TYPE_IO)
1665                 return AE_OK;
1666
1667         /*
1668          * The first address region returned is the data port, and
1669          * the second address region returned is the status/command
1670          * port.
1671          */
1672         if (ec->data_addr == 0)
1673                 ec->data_addr = resource->data.io.minimum;
1674         else if (ec->command_addr == 0)
1675                 ec->command_addr = resource->data.io.minimum;
1676         else
1677                 return AE_CTRL_TERMINATE;
1678
1679         return AE_OK;
1680 }
1681
1682 static const struct acpi_device_id ec_device_ids[] = {
1683         {"PNP0C09", 0},
1684         {"", 0},
1685 };
1686
1687 int __init acpi_ec_dsdt_probe(void)
1688 {
1689         acpi_status status;
1690         struct acpi_ec *ec;
1691         int ret;
1692
1693         ec = acpi_ec_alloc();
1694         if (!ec)
1695                 return -ENOMEM;
1696         /*
1697          * At this point, the namespace is initialized, so start to find
1698          * the namespace objects.
1699          */
1700         status = acpi_get_devices(ec_device_ids[0].id,
1701                                   ec_parse_device, ec, NULL);
1702         if (ACPI_FAILURE(status) || !ec->handle) {
1703                 ret = -ENODEV;
1704                 goto error;
1705         }
1706         /*
1707          * When the DSDT EC is available, always re-configure boot EC to
1708          * have _REG evaluated. _REG can only be evaluated after the
1709          * namespace initialization.
1710          * At this point, the GPE is not fully initialized, so do not to
1711          * handle the events.
1712          */
1713         ret = acpi_config_boot_ec(ec, ec->handle, false, false);
1714 error:
1715         if (ret)
1716                 acpi_ec_free(ec);
1717         return ret;
1718 }
1719
1720 /*
1721  * If the DSDT EC is not functioning, we still need to prepare a fully
1722  * functioning ECDT EC first in order to handle the events.
1723  * https://bugzilla.kernel.org/show_bug.cgi?id=115021
1724  */
1725 static int __init acpi_ec_ecdt_start(void)
1726 {
1727         acpi_handle handle;
1728
1729         if (!boot_ec)
1730                 return -ENODEV;
1731         /*
1732          * The DSDT EC should have already been started in
1733          * acpi_ec_add().
1734          */
1735         if (!boot_ec_is_ecdt)
1736                 return -ENODEV;
1737
1738         /*
1739          * At this point, the namespace and the GPE is initialized, so
1740          * start to find the namespace objects and handle the events.
1741          */
1742         if (!acpi_ec_ecdt_get_handle(&handle))
1743                 return -ENODEV;
1744         return acpi_config_boot_ec(boot_ec, handle, true, true);
1745 }
1746
1747 #if 0
1748 /*
1749  * Some EC firmware variations refuses to respond QR_EC when SCI_EVT is not
1750  * set, for which case, we complete the QR_EC without issuing it to the
1751  * firmware.
1752  * https://bugzilla.kernel.org/show_bug.cgi?id=82611
1753  * https://bugzilla.kernel.org/show_bug.cgi?id=97381
1754  */
1755 static int ec_flag_query_handshake(const struct dmi_system_id *id)
1756 {
1757         pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
1758         EC_FLAGS_QUERY_HANDSHAKE = 1;
1759         return 0;
1760 }
1761 #endif
1762
1763 /*
1764  * On some hardware it is necessary to clear events accumulated by the EC during
1765  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1766  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1767  *
1768  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1769  *
1770  * Ideally, the EC should also be instructed NOT to accumulate events during
1771  * sleep (which Windows seems to do somehow), but the interface to control this
1772  * behaviour is not known at this time.
1773  *
1774  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1775  * however it is very likely that other Samsung models are affected.
1776  *
1777  * On systems which don't accumulate _Q events during sleep, this extra check
1778  * should be harmless.
1779  */
1780 static int ec_clear_on_resume(const struct dmi_system_id *id)
1781 {
1782         pr_debug("Detected system needing EC poll on resume.\n");
1783         EC_FLAGS_CLEAR_ON_RESUME = 1;
1784         ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1785         return 0;
1786 }
1787
1788 /*
1789  * Some ECDTs contain wrong register addresses.
1790  * MSI MS-171F
1791  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1792  */
1793 static int ec_correct_ecdt(const struct dmi_system_id *id)
1794 {
1795         pr_debug("Detected system needing ECDT address correction.\n");
1796         EC_FLAGS_CORRECT_ECDT = 1;
1797         return 0;
1798 }
1799
1800 static struct dmi_system_id ec_dmi_table[] __initdata = {
1801         {
1802         ec_correct_ecdt, "MSI MS-171F", {
1803         DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1804         DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
1805         {
1806         ec_clear_on_resume, "Samsung hardware", {
1807         DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1808         {},
1809 };
1810
1811 int __init acpi_ec_ecdt_probe(void)
1812 {
1813         int ret;
1814         acpi_status status;
1815         struct acpi_table_ecdt *ecdt_ptr;
1816         struct acpi_ec *ec;
1817
1818         ec = acpi_ec_alloc();
1819         if (!ec)
1820                 return -ENOMEM;
1821         /*
1822          * Generate a boot ec context
1823          */
1824         dmi_check_system(ec_dmi_table);
1825         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1826                                 (struct acpi_table_header **)&ecdt_ptr);
1827         if (ACPI_FAILURE(status)) {
1828                 ret = -ENODEV;
1829                 goto error;
1830         }
1831
1832         if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
1833                 /*
1834                  * Asus X50GL:
1835                  * https://bugzilla.kernel.org/show_bug.cgi?id=11880
1836                  */
1837                 ret = -ENODEV;
1838                 goto error;
1839         }
1840
1841         if (EC_FLAGS_CORRECT_ECDT) {
1842                 ec->command_addr = ecdt_ptr->data.address;
1843                 ec->data_addr = ecdt_ptr->control.address;
1844         } else {
1845                 ec->command_addr = ecdt_ptr->control.address;
1846                 ec->data_addr = ecdt_ptr->data.address;
1847         }
1848         ec->gpe = ecdt_ptr->gpe;
1849
1850         /*
1851          * At this point, the namespace is not initialized, so do not find
1852          * the namespace objects, or handle the events.
1853          */
1854         ret = acpi_config_boot_ec(ec, ACPI_ROOT_OBJECT, false, true);
1855 error:
1856         if (ret)
1857                 acpi_ec_free(ec);
1858         return ret;
1859 }
1860
1861 #ifdef CONFIG_PM_SLEEP
1862 static int acpi_ec_suspend(struct device *dev)
1863 {
1864         struct acpi_ec *ec =
1865                 acpi_driver_data(to_acpi_device(dev));
1866
1867         if (ec_freeze_events)
1868                 acpi_ec_disable_event(ec);
1869         return 0;
1870 }
1871
1872 static int acpi_ec_resume(struct device *dev)
1873 {
1874         struct acpi_ec *ec =
1875                 acpi_driver_data(to_acpi_device(dev));
1876
1877         acpi_ec_enable_event(ec);
1878         return 0;
1879 }
1880 #endif
1881
1882 static const struct dev_pm_ops acpi_ec_pm = {
1883         SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
1884 };
1885
1886 static int param_set_event_clearing(const char *val, struct kernel_param *kp)
1887 {
1888         int result = 0;
1889
1890         if (!strncmp(val, "status", sizeof("status") - 1)) {
1891                 ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1892                 pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
1893         } else if (!strncmp(val, "query", sizeof("query") - 1)) {
1894                 ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
1895                 pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
1896         } else if (!strncmp(val, "event", sizeof("event") - 1)) {
1897                 ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
1898                 pr_info("Assuming SCI_EVT clearing on event reads\n");
1899         } else
1900                 result = -EINVAL;
1901         return result;
1902 }
1903
1904 static int param_get_event_clearing(char *buffer, struct kernel_param *kp)
1905 {
1906         switch (ec_event_clearing) {
1907         case ACPI_EC_EVT_TIMING_STATUS:
1908                 return sprintf(buffer, "status");
1909         case ACPI_EC_EVT_TIMING_QUERY:
1910                 return sprintf(buffer, "query");
1911         case ACPI_EC_EVT_TIMING_EVENT:
1912                 return sprintf(buffer, "event");
1913         default:
1914                 return sprintf(buffer, "invalid");
1915         }
1916         return 0;
1917 }
1918
1919 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
1920                   NULL, 0644);
1921 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
1922
1923 static struct acpi_driver acpi_ec_driver = {
1924         .name = "ec",
1925         .class = ACPI_EC_CLASS,
1926         .ids = ec_device_ids,
1927         .ops = {
1928                 .add = acpi_ec_add,
1929                 .remove = acpi_ec_remove,
1930                 },
1931         .drv.pm = &acpi_ec_pm,
1932 };
1933
1934 static inline int acpi_ec_query_init(void)
1935 {
1936         if (!ec_query_wq) {
1937                 ec_query_wq = alloc_workqueue("kec_query", 0,
1938                                               ec_max_queries);
1939                 if (!ec_query_wq)
1940                         return -ENODEV;
1941         }
1942         return 0;
1943 }
1944
1945 static inline void acpi_ec_query_exit(void)
1946 {
1947         if (ec_query_wq) {
1948                 destroy_workqueue(ec_query_wq);
1949                 ec_query_wq = NULL;
1950         }
1951 }
1952
1953 int __init acpi_ec_init(void)
1954 {
1955         int result;
1956         int ecdt_fail, dsdt_fail;
1957
1958         /* register workqueue for _Qxx evaluations */
1959         result = acpi_ec_query_init();
1960         if (result)
1961                 return result;
1962
1963         /* Drivers must be started after acpi_ec_query_init() */
1964         ecdt_fail = acpi_ec_ecdt_start();
1965         dsdt_fail = acpi_bus_register_driver(&acpi_ec_driver);
1966         return ecdt_fail && dsdt_fail ? -ENODEV : 0;
1967 }
1968
1969 /* EC driver currently not unloadable */
1970 #if 0
1971 static void __exit acpi_ec_exit(void)
1972 {
1973
1974         acpi_bus_unregister_driver(&acpi_ec_driver);
1975         acpi_ec_query_exit();
1976 }
1977 #endif  /* 0 */