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 <[email protected]>
   6  *            2006, 2007 Alexey Starikovskiy <[email protected]>
   7  *            2006       Denis Sadykov <[email protected]>
   8  *            2004       Luming Yu <[email protected]>
   9  *            2001, 2002 Andy Grover <[email protected]>
  10  *            2001, 2002 Paul Diefenbaugh <[email protected]>
  11  *  Copyright (C) 2008      Alexey Starikovskiy <[email protected]>
  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
 105 enum {
 106         EC_FLAGS_QUERY_PENDING,         /* Query is pending */
 107         EC_FLAGS_QUERY_GUARDING,        /* Guard for SCI_EVT check */
 108         EC_FLAGS_HANDLERS_INSTALLED,    /* Handlers for GPE and
 109                                          * OpReg are installed */
 110         EC_FLAGS_STARTED,               /* Driver is started */
 111         EC_FLAGS_STOPPED,               /* Driver is stopped */
 112         EC_FLAGS_COMMAND_STORM,         /* GPE storms occurred to the
 113                                          * current command processing */
 114 };
 115
 116 #define ACPI_EC_COMMAND_POLL            0x01 /* Available for command byte */
 117 #define ACPI_EC_COMMAND_COMPLETE        0x02 /* Completed last byte */
 118
 119 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
 120 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
 121 module_param(ec_delay, uint, 0644);
 122 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
 123
 124 static bool ec_busy_polling __read_mostly;
 125 module_param(ec_busy_polling, bool, 0644);
 126 MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction");
 127
 128 static unsigned int ec_polling_guard __read_mostly = ACPI_EC_UDELAY_POLL;
 129 module_param(ec_polling_guard, uint, 0644);
 130 MODULE_PARM_DESC(ec_polling_guard, "Guard time(us) between EC accesses in polling modes");
 131
 132 static unsigned int ec_event_clearing __read_mostly = ACPI_EC_EVT_TIMING_QUERY;
 133
 134 /*
 135  * If the number of false interrupts per one transaction exceeds
 136  * this threshold, will think there is a GPE storm happened and
 137  * will disable the GPE for normal transaction.
 138  */
 139 static unsigned int ec_storm_threshold  __read_mostly = 8;
 140 module_param(ec_storm_threshold, uint, 0644);
 141 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
 142
 143 struct acpi_ec_query_handler {
 144         struct list_head node;
 145         acpi_ec_query_func func;
 146         acpi_handle handle;
 147         void *data;
 148         u8 query_bit;
 149         struct kref kref;
 150 };
 151
 152 struct transaction {
 153         const u8 *wdata;
 154         u8 *rdata;
 155         unsigned short irq_count;
 156         u8 command;
 157         u8 wi;
 158         u8 ri;
 159         u8 wlen;
 160         u8 rlen;
 161         u8 flags;
 162 };
 163
 164 struct acpi_ec_query {
 165         struct transaction transaction;
 166         struct work_struct work;
 167         struct acpi_ec_query_handler *handler;
 168 };
 169
 170 static int acpi_ec_query(struct acpi_ec *ec, u8 *data);
 171 static void advance_transaction(struct acpi_ec *ec);
 172 static void acpi_ec_event_handler(struct work_struct *work);
 173 static void acpi_ec_event_processor(struct work_struct *work);
 174
 175 struct acpi_ec *boot_ec, *first_ec;
 176 EXPORT_SYMBOL(first_ec);
 177
 178 static int EC_FLAGS_VALIDATE_ECDT; /* ASUStec ECDTs need to be validated */
 179 static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
 180 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
 181 static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
 182
 183 /* --------------------------------------------------------------------------
 184  *                           Logging/Debugging
 185  * -------------------------------------------------------------------------- */
 186
 187 /*
 188  * Splitters used by the developers to track the boundary of the EC
 189  * handling processes.
 190  */
 191 #ifdef DEBUG
 192 #define EC_DBG_SEP      " "
 193 #define EC_DBG_DRV      "+++++"
 194 #define EC_DBG_STM      "====="
 195 #define EC_DBG_REQ      "*****"
 196 #define EC_DBG_EVT      "#####"
 197 #else
 198 #define EC_DBG_SEP      ""
 199 #define EC_DBG_DRV
 200 #define EC_DBG_STM
 201 #define EC_DBG_REQ
 202 #define EC_DBG_EVT
 203 #endif
 204
 205 #define ec_log_raw(fmt, ...) \
 206         pr_info(fmt "\n", ##__VA_ARGS__)
 207 #define ec_dbg_raw(fmt, ...) \
 208         pr_debug(fmt "\n", ##__VA_ARGS__)
 209 #define ec_log(filter, fmt, ...) \
 210         ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
 211 #define ec_dbg(filter, fmt, ...) \
 212         ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
 213
 214 #define ec_log_drv(fmt, ...) \
 215         ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
 216 #define ec_dbg_drv(fmt, ...) \
 217         ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
 218 #define ec_dbg_stm(fmt, ...) \
 219         ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
 220 #define ec_dbg_req(fmt, ...) \
 221         ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
 222 #define ec_dbg_evt(fmt, ...) \
 223         ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
 224 #define ec_dbg_ref(ec, fmt, ...) \
 225         ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
 226
 227 /* --------------------------------------------------------------------------
 228  *                           Device Flags
 229  * -------------------------------------------------------------------------- */
 230
 231 static bool acpi_ec_started(struct acpi_ec *ec)
 232 {
 233         return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
 234                !test_bit(EC_FLAGS_STOPPED, &ec->flags);
 235 }
 236
 237 static bool acpi_ec_flushed(struct acpi_ec *ec)
 238 {
 239         return ec->reference_count == 1;
 240 }
 241
 242 /* --------------------------------------------------------------------------
 243  *                           EC Registers
 244  * -------------------------------------------------------------------------- */
 245
 246 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
 247 {
 248         u8 x = inb(ec->command_addr);
 249
 250         ec_dbg_raw("EC_SC(R) = 0x%2.2x "
 251                    "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
 252                    x,
 253                    !!(x & ACPI_EC_FLAG_SCI),
 254                    !!(x & ACPI_EC_FLAG_BURST),
 255                    !!(x & ACPI_EC_FLAG_CMD),
 256                    !!(x & ACPI_EC_FLAG_IBF),
 257                    !!(x & ACPI_EC_FLAG_OBF));
 258         return x;
 259 }
 260
 261 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
 262 {
 263         u8 x = inb(ec->data_addr);
 264
 265         ec->timestamp = jiffies;
 266         ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
 267         return x;
 268 }
 269
 270 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
 271 {
 272         ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
 273         outb(command, ec->command_addr);
 274         ec->timestamp = jiffies;
 275 }
 276
 277 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
 278 {
 279         ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
 280         outb(data, ec->data_addr);
 281         ec->timestamp = jiffies;
 282 }
 283
 284 #ifdef DEBUG
 285 static const char *acpi_ec_cmd_string(u8 cmd)
 286 {
 287         switch (cmd) {
 288         case 0x80:
 289                 return "RD_EC";
 290         case 0x81:
 291                 return "WR_EC";
 292         case 0x82:
 293                 return "BE_EC";
 294         case 0x83:
 295                 return "BD_EC";
 296         case 0x84:
 297                 return "QR_EC";
 298         }
 299         return "UNKNOWN";
 300 }
 301 #else
 302 #define acpi_ec_cmd_string(cmd)         "UNDEF"
 303 #endif
 304
 305 /* --------------------------------------------------------------------------
 306  *                           GPE Registers
 307  * -------------------------------------------------------------------------- */
 308
 309 static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec)
 310 {
 311         acpi_event_status gpe_status = 0;
 312
 313         (void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
 314         return (gpe_status & ACPI_EVENT_FLAG_STATUS_SET) ? true : false;
 315 }
 316
 317 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
 318 {
 319         if (open)
 320                 acpi_enable_gpe(NULL, ec->gpe);
 321         else {
 322                 BUG_ON(ec->reference_count < 1);
 323                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
 324         }
 325         if (acpi_ec_is_gpe_raised(ec)) {
 326                 /*
 327                  * On some platforms, EN=1 writes cannot trigger GPE. So
 328                  * software need to manually trigger a pseudo GPE event on
 329                  * EN=1 writes.
 330                  */
 331                 ec_dbg_raw("Polling quirk");
 332                 advance_transaction(ec);
 333         }
 334 }
 335
 336 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
 337 {
 338         if (close)
 339                 acpi_disable_gpe(NULL, ec->gpe);
 340         else {
 341                 BUG_ON(ec->reference_count < 1);
 342                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
 343         }
 344 }
 345
 346 static inline void acpi_ec_clear_gpe(struct acpi_ec *ec)
 347 {
 348         /*
 349          * GPE STS is a W1C register, which means:
 350          * 1. Software can clear it without worrying about clearing other
 351          *    GPEs' STS bits when the hardware sets them in parallel.
 352          * 2. As long as software can ensure only clearing it when it is
 353          *    set, hardware won't set it in parallel.
 354          * So software can clear GPE in any contexts.
 355          * Warning: do not move the check into advance_transaction() as the
 356          * EC commands will be sent without GPE raised.
 357          */
 358         if (!acpi_ec_is_gpe_raised(ec))
 359                 return;
 360         acpi_clear_gpe(NULL, ec->gpe);
 361 }
 362
 363 /* --------------------------------------------------------------------------
 364  *                           Transaction Management
 365  * -------------------------------------------------------------------------- */
 366
 367 static void acpi_ec_submit_request(struct acpi_ec *ec)
 368 {
 369         ec->reference_count++;
 370         if (ec->reference_count == 1)
 371                 acpi_ec_enable_gpe(ec, true);
 372 }
 373
 374 static void acpi_ec_complete_request(struct acpi_ec *ec)
 375 {
 376         bool flushed = false;
 377
 378         ec->reference_count--;
 379         if (ec->reference_count == 0)
 380                 acpi_ec_disable_gpe(ec, true);
 381         flushed = acpi_ec_flushed(ec);
 382         if (flushed)
 383                 wake_up(&ec->wait);
 384 }
 385
 386 static void acpi_ec_set_storm(struct acpi_ec *ec, u8 flag)
 387 {
 388         if (!test_bit(flag, &ec->flags)) {
 389                 acpi_ec_disable_gpe(ec, false);
 390                 ec_dbg_drv("Polling enabled");
 391                 set_bit(flag, &ec->flags);
 392         }
 393 }
 394
 395 static void acpi_ec_clear_storm(struct acpi_ec *ec, u8 flag)
 396 {
 397         if (test_bit(flag, &ec->flags)) {
 398                 clear_bit(flag, &ec->flags);
 399                 acpi_ec_enable_gpe(ec, false);
 400                 ec_dbg_drv("Polling disabled");
 401         }
 402 }
 403
 404 /*
 405  * acpi_ec_submit_flushable_request() - Increase the reference count unless
 406  *                                      the flush operation is not in
 407  *                                      progress
 408  * @ec: the EC device
 409  *
 410  * This function must be used before taking a new action that should hold
 411  * the reference count.  If this function returns false, then the action
 412  * must be discarded or it will prevent the flush operation from being
 413  * completed.
 414  */
 415 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
 416 {
 417         if (!acpi_ec_started(ec))
 418                 return false;
 419         acpi_ec_submit_request(ec);
 420         return true;
 421 }
 422
 423 static void acpi_ec_submit_query(struct acpi_ec *ec)
 424 {
 425         if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
 426                 ec_dbg_evt("Command(%s) submitted/blocked",
 427                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 428                 ec->nr_pending_queries++;
 429                 schedule_work(&ec->work);
 430         }
 431 }
 432
 433 static void acpi_ec_complete_query(struct acpi_ec *ec)
 434 {
 435         if (test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
 436                 clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
 437                 ec_dbg_evt("Command(%s) unblocked",
 438                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 439         }
 440 }
 441
 442 static bool acpi_ec_guard_event(struct acpi_ec *ec)
 443 {
 444         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
 445             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY ||
 446             !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) ||
 447             (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY))
 448                 return false;
 449
 450         /*
 451          * Postpone the query submission to allow the firmware to proceed,
 452          * we shouldn't check SCI_EVT before the firmware reflagging it.
 453          */
 454         return true;
 455 }
 456
 457 static int ec_transaction_polled(struct acpi_ec *ec)
 458 {
 459         unsigned long flags;
 460         int ret = 0;
 461
 462         spin_lock_irqsave(&ec->lock, flags);
 463         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
 464                 ret = 1;
 465         spin_unlock_irqrestore(&ec->lock, flags);
 466         return ret;
 467 }
 468
 469 static int ec_transaction_completed(struct acpi_ec *ec)
 470 {
 471         unsigned long flags;
 472         int ret = 0;
 473
 474         spin_lock_irqsave(&ec->lock, flags);
 475         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
 476                 ret = 1;
 477         spin_unlock_irqrestore(&ec->lock, flags);
 478         return ret;
 479 }
 480
 481 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
 482 {
 483         ec->curr->flags |= flag;
 484         if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
 485                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS &&
 486                     flag == ACPI_EC_COMMAND_POLL)
 487                         acpi_ec_complete_query(ec);
 488                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY &&
 489                     flag == ACPI_EC_COMMAND_COMPLETE)
 490                         acpi_ec_complete_query(ec);
 491                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 492                     flag == ACPI_EC_COMMAND_COMPLETE)
 493                         set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
 494         }
 495 }
 496
 497 static void advance_transaction(struct acpi_ec *ec)
 498 {
 499         struct transaction *t;
 500         u8 status;
 501         bool wakeup = false;
 502
 503         ec_dbg_stm("%s (%d)", in_interrupt() ? "IRQ" : "TASK",
 504                    smp_processor_id());
 505         /*
 506          * By always clearing STS before handling all indications, we can
 507          * ensure a hardware STS 0->1 change after this clearing can always
 508          * trigger a GPE interrupt.
 509          */
 510         acpi_ec_clear_gpe(ec);
 511         status = acpi_ec_read_status(ec);
 512         t = ec->curr;
 513         /*
 514          * Another IRQ or a guarded polling mode advancement is detected,
 515          * the next QR_EC submission is then allowed.
 516          */
 517         if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
 518                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 519                     (!ec->nr_pending_queries ||
 520                      test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) {
 521                         clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
 522                         acpi_ec_complete_query(ec);
 523                 }
 524         }
 525         if (!t)
 526                 goto err;
 527         if (t->flags & ACPI_EC_COMMAND_POLL) {
 528                 if (t->wlen > t->wi) {
 529                         if ((status & ACPI_EC_FLAG_IBF) == 0)
 530                                 acpi_ec_write_data(ec, t->wdata[t->wi++]);
 531                         else
 532                                 goto err;
 533                 } else if (t->rlen > t->ri) {
 534                         if ((status & ACPI_EC_FLAG_OBF) == 1) {
 535                                 t->rdata[t->ri++] = acpi_ec_read_data(ec);
 536                                 if (t->rlen == t->ri) {
 537                                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 538                                         if (t->command == ACPI_EC_COMMAND_QUERY)
 539                                                 ec_dbg_evt("Command(%s) completed by hardware",
 540                                                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 541                                         wakeup = true;
 542                                 }
 543                         } else
 544                                 goto err;
 545                 } else if (t->wlen == t->wi &&
 546                            (status & ACPI_EC_FLAG_IBF) == 0) {
 547                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 548                         wakeup = true;
 549                 }
 550                 goto out;
 551         } else {
 552                 if (EC_FLAGS_QUERY_HANDSHAKE &&
 553                     !(status & ACPI_EC_FLAG_SCI) &&
 554                     (t->command == ACPI_EC_COMMAND_QUERY)) {
 555                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
 556                         t->rdata[t->ri++] = 0x00;
 557                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 558                         ec_dbg_evt("Command(%s) completed by software",
 559                                    acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 560                         wakeup = true;
 561                 } else if ((status & ACPI_EC_FLAG_IBF) == 0) {
 562                         acpi_ec_write_cmd(ec, t->command);
 563                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
 564                 } else
 565                         goto err;
 566                 goto out;
 567         }
 568 err:
 569         /*
 570          * If SCI bit is set, then don't think it's a false IRQ
 571          * otherwise will take a not handled IRQ as a false one.
 572          */
 573         if (!(status & ACPI_EC_FLAG_SCI)) {
 574                 if (in_interrupt() && t) {
 575                         if (t->irq_count < ec_storm_threshold)
 576                                 ++t->irq_count;
 577                         /* Allow triggering on 0 threshold */
 578                         if (t->irq_count == ec_storm_threshold)
 579                                 acpi_ec_set_storm(ec, EC_FLAGS_COMMAND_STORM);
 580                 }
 581         }
 582 out:
 583         if (status & ACPI_EC_FLAG_SCI)
 584                 acpi_ec_submit_query(ec);
 585         if (wakeup && in_interrupt())
 586                 wake_up(&ec->wait);
 587 }
 588
 589 static void start_transaction(struct acpi_ec *ec)
 590 {
 591         ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
 592         ec->curr->flags = 0;
 593 }
 594
 595 static int ec_guard(struct acpi_ec *ec)
 596 {
 597         unsigned long guard = usecs_to_jiffies(ec_polling_guard);
 598         unsigned long timeout = ec->timestamp + guard;
 599
 600         do {
 601                 if (ec_busy_polling) {
 602                         /* Perform busy polling */
 603                         if (ec_transaction_completed(ec))
 604                                 return 0;
 605                         udelay(jiffies_to_usecs(guard));
 606                 } else {
 607                         /*
 608                          * Perform wait polling
 609                          *
 610                          * For SCI_EVT clearing timing of "event",
 611                          * performing guarding before re-checking the
 612                          * SCI_EVT. Otherwise, such guarding is not needed
 613                          * due to the old practices.
 614                          */
 615                         if (!ec_transaction_polled(ec) &&
 616                             !acpi_ec_guard_event(ec))
 617                                 break;
 618                         if (wait_event_timeout(ec->wait,
 619                                                ec_transaction_completed(ec),
 620                                                guard))
 621                                 return 0;
 622                 }
 623                 /* Guard the register accesses for the polling modes */
 624         } while (time_before(jiffies, timeout));
 625         return -ETIME;
 626 }
 627
 628 static int ec_poll(struct acpi_ec *ec)
 629 {
 630         unsigned long flags;
 631         int repeat = 5; /* number of command restarts */
 632
 633         while (repeat--) {
 634                 unsigned long delay = jiffies +
 635                         msecs_to_jiffies(ec_delay);
 636                 do {
 637                         if (!ec_guard(ec))
 638                                 return 0;
 639                         spin_lock_irqsave(&ec->lock, flags);
 640                         advance_transaction(ec);
 641                         spin_unlock_irqrestore(&ec->lock, flags);
 642                 } while (time_before(jiffies, delay));
 643                 pr_debug("controller reset, restart transaction\n");
 644                 spin_lock_irqsave(&ec->lock, flags);
 645                 start_transaction(ec);
 646                 spin_unlock_irqrestore(&ec->lock, flags);
 647         }
 648         return -ETIME;
 649 }
 650
 651 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
 652                                         struct transaction *t)
 653 {
 654         unsigned long tmp;
 655         int ret = 0;
 656
 657         /* start transaction */
 658         spin_lock_irqsave(&ec->lock, tmp);
 659         /* Enable GPE for command processing (IBF=0/OBF=1) */
 660         if (!acpi_ec_submit_flushable_request(ec)) {
 661                 ret = -EINVAL;
 662                 goto unlock;
 663         }
 664         ec_dbg_ref(ec, "Increase command");
 665         /* following two actions should be kept atomic */
 666         ec->curr = t;
 667         ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
 668         start_transaction(ec);
 669         spin_unlock_irqrestore(&ec->lock, tmp);
 670
 671         ret = ec_poll(ec);
 672
 673         spin_lock_irqsave(&ec->lock, tmp);
 674         if (t->irq_count == ec_storm_threshold)
 675                 acpi_ec_clear_storm(ec, EC_FLAGS_COMMAND_STORM);
 676         ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
 677         ec->curr = NULL;
 678         /* Disable GPE for command processing (IBF=0/OBF=1) */
 679         acpi_ec_complete_request(ec);
 680         ec_dbg_ref(ec, "Decrease command");
 681 unlock:
 682         spin_unlock_irqrestore(&ec->lock, tmp);
 683         return ret;
 684 }
 685
 686 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
 687 {
 688         int status;
 689         u32 glk;
 690
 691         if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
 692                 return -EINVAL;
 693         if (t->rdata)
 694                 memset(t->rdata, 0, t->rlen);
 695
 696         mutex_lock(&ec->mutex);
 697         if (ec->global_lock) {
 698                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
 699                 if (ACPI_FAILURE(status)) {
 700                         status = -ENODEV;
 701                         goto unlock;
 702                 }
 703         }
 704
 705         status = acpi_ec_transaction_unlocked(ec, t);
 706
 707         if (ec->global_lock)
 708                 acpi_release_global_lock(glk);
 709 unlock:
 710         mutex_unlock(&ec->mutex);
 711         return status;
 712 }
 713
 714 static int acpi_ec_burst_enable(struct acpi_ec *ec)
 715 {
 716         u8 d;
 717         struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
 718                                 .wdata = NULL, .rdata = &d,
 719                                 .wlen = 0, .rlen = 1};
 720
 721         return acpi_ec_transaction(ec, &t);
 722 }
 723
 724 static int acpi_ec_burst_disable(struct acpi_ec *ec)
 725 {
 726         struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
 727                                 .wdata = NULL, .rdata = NULL,
 728                                 .wlen = 0, .rlen = 0};
 729
 730         return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
 731                                 acpi_ec_transaction(ec, &t) : 0;
 732 }
 733
 734 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
 735 {
 736         int result;
 737         u8 d;
 738         struct transaction t = {.command = ACPI_EC_COMMAND_READ,
 739                                 .wdata = &address, .rdata = &d,
 740                                 .wlen = 1, .rlen = 1};
 741
 742         result = acpi_ec_transaction(ec, &t);
 743         *data = d;
 744         return result;
 745 }
 746
 747 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
 748 {
 749         u8 wdata[2] = { address, data };
 750         struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
 751                                 .wdata = wdata, .rdata = NULL,
 752                                 .wlen = 2, .rlen = 0};
 753
 754         return acpi_ec_transaction(ec, &t);
 755 }
 756
 757 int ec_read(u8 addr, u8 *val)
 758 {
 759         int err;
 760         u8 temp_data;
 761
 762         if (!first_ec)
 763                 return -ENODEV;
 764
 765         err = acpi_ec_read(first_ec, addr, &temp_data);
 766
 767         if (!err) {
 768                 *val = temp_data;
 769                 return 0;
 770         }
 771         return err;
 772 }
 773 EXPORT_SYMBOL(ec_read);
 774
 775 int ec_write(u8 addr, u8 val)
 776 {
 777         int err;
 778
 779         if (!first_ec)
 780                 return -ENODEV;
 781
 782         err = acpi_ec_write(first_ec, addr, val);
 783
 784         return err;
 785 }
 786 EXPORT_SYMBOL(ec_write);
 787
 788 int ec_transaction(u8 command,
 789                    const u8 *wdata, unsigned wdata_len,
 790                    u8 *rdata, unsigned rdata_len)
 791 {
 792         struct transaction t = {.command = command,
 793                                 .wdata = wdata, .rdata = rdata,
 794                                 .wlen = wdata_len, .rlen = rdata_len};
 795
 796         if (!first_ec)
 797                 return -ENODEV;
 798
 799         return acpi_ec_transaction(first_ec, &t);
 800 }
 801 EXPORT_SYMBOL(ec_transaction);
 802
 803 /* Get the handle to the EC device */
 804 acpi_handle ec_get_handle(void)
 805 {
 806         if (!first_ec)
 807                 return NULL;
 808         return first_ec->handle;
 809 }
 810 EXPORT_SYMBOL(ec_get_handle);
 811
 812 /*
 813  * Process _Q events that might have accumulated in the EC.
 814  * Run with locked ec mutex.
 815  */
 816 static void acpi_ec_clear(struct acpi_ec *ec)
 817 {
 818         int i, status;
 819         u8 value = 0;
 820
 821         for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
 822                 status = acpi_ec_query(ec, &value);
 823                 if (status || !value)
 824                         break;
 825         }
 826
 827         if (unlikely(i == ACPI_EC_CLEAR_MAX))
 828                 pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
 829         else
 830                 pr_info("%d stale EC events cleared\n", i);
 831 }
 832
 833 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
 834 {
 835         unsigned long flags;
 836
 837         spin_lock_irqsave(&ec->lock, flags);
 838         if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
 839                 ec_dbg_drv("Starting EC");
 840                 /* Enable GPE for event processing (SCI_EVT=1) */
 841                 if (!resuming) {
 842                         acpi_ec_submit_request(ec);
 843                         ec_dbg_ref(ec, "Increase driver");
 844                 }
 845                 ec_log_drv("EC started");
 846         }
 847         spin_unlock_irqrestore(&ec->lock, flags);
 848 }
 849
 850 static bool acpi_ec_stopped(struct acpi_ec *ec)
 851 {
 852         unsigned long flags;
 853         bool flushed;
 854
 855         spin_lock_irqsave(&ec->lock, flags);
 856         flushed = acpi_ec_flushed(ec);
 857         spin_unlock_irqrestore(&ec->lock, flags);
 858         return flushed;
 859 }
 860
 861 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
 862 {
 863         unsigned long flags;
 864
 865         spin_lock_irqsave(&ec->lock, flags);
 866         if (acpi_ec_started(ec)) {
 867                 ec_dbg_drv("Stopping EC");
 868                 set_bit(EC_FLAGS_STOPPED, &ec->flags);
 869                 spin_unlock_irqrestore(&ec->lock, flags);
 870                 wait_event(ec->wait, acpi_ec_stopped(ec));
 871                 spin_lock_irqsave(&ec->lock, flags);
 872                 /* Disable GPE for event processing (SCI_EVT=1) */
 873                 if (!suspending) {
 874                         acpi_ec_complete_request(ec);
 875                         ec_dbg_ref(ec, "Decrease driver");
 876                 }
 877                 clear_bit(EC_FLAGS_STARTED, &ec->flags);
 878                 clear_bit(EC_FLAGS_STOPPED, &ec->flags);
 879                 ec_log_drv("EC stopped");
 880         }
 881         spin_unlock_irqrestore(&ec->lock, flags);
 882 }
 883
 884 void acpi_ec_block_transactions(void)
 885 {
 886         struct acpi_ec *ec = first_ec;
 887
 888         if (!ec)
 889                 return;
 890
 891         mutex_lock(&ec->mutex);
 892         /* Prevent transactions from being carried out */
 893         acpi_ec_stop(ec, true);
 894         mutex_unlock(&ec->mutex);
 895 }
 896
 897 void acpi_ec_unblock_transactions(void)
 898 {
 899         struct acpi_ec *ec = first_ec;
 900
 901         if (!ec)
 902                 return;
 903
 904         /* Allow transactions to be carried out again */
 905         acpi_ec_start(ec, true);
 906
 907         if (EC_FLAGS_CLEAR_ON_RESUME)
 908                 acpi_ec_clear(ec);
 909 }
 910
 911 void acpi_ec_unblock_transactions_early(void)
 912 {
 913         /*
 914          * Allow transactions to happen again (this function is called from
 915          * atomic context during wakeup, so we don't need to acquire the mutex).
 916          */
 917         if (first_ec)
 918                 acpi_ec_start(first_ec, true);
 919 }
 920
 921 /* --------------------------------------------------------------------------
 922                                 Event Management
 923    -------------------------------------------------------------------------- */
 924 static struct acpi_ec_query_handler *
 925 acpi_ec_get_query_handler(struct acpi_ec_query_handler *handler)
 926 {
 927         if (handler)
 928                 kref_get(&handler->kref);
 929         return handler;
 930 }
 931
 932 static void acpi_ec_query_handler_release(struct kref *kref)
 933 {
 934         struct acpi_ec_query_handler *handler =
 935                 container_of(kref, struct acpi_ec_query_handler, kref);
 936
 937         kfree(handler);
 938 }
 939
 940 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
 941 {
 942         kref_put(&handler->kref, acpi_ec_query_handler_release);
 943 }
 944
 945 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
 946                               acpi_handle handle, acpi_ec_query_func func,
 947                               void *data)
 948 {
 949         struct acpi_ec_query_handler *handler =
 950             kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
 951
 952         if (!handler)
 953                 return -ENOMEM;
 954
 955         handler->query_bit = query_bit;
 956         handler->handle = handle;
 957         handler->func = func;
 958         handler->data = data;
 959         mutex_lock(&ec->mutex);
 960         kref_init(&handler->kref);
 961         list_add(&handler->node, &ec->list);
 962         mutex_unlock(&ec->mutex);
 963         return 0;
 964 }
 965 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
 966
 967 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
 968 {
 969         struct acpi_ec_query_handler *handler, *tmp;
 970         LIST_HEAD(free_list);
 971
 972         mutex_lock(&ec->mutex);
 973         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
 974                 if (query_bit == handler->query_bit) {
 975                         list_del_init(&handler->node);
 976                         list_add(&handler->node, &free_list);
 977                 }
 978         }
 979         mutex_unlock(&ec->mutex);
 980         list_for_each_entry_safe(handler, tmp, &free_list, node)
 981                 acpi_ec_put_query_handler(handler);
 982 }
 983 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
 984
 985 static struct acpi_ec_query *acpi_ec_create_query(u8 *pval)
 986 {
 987         struct acpi_ec_query *q;
 988         struct transaction *t;
 989
 990         q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
 991         if (!q)
 992                 return NULL;
 993         INIT_WORK(&q->work, acpi_ec_event_processor);
 994         t = &q->transaction;
 995         t->command = ACPI_EC_COMMAND_QUERY;
 996         t->rdata = pval;
 997         t->rlen = 1;
 998         return q;
 999 }
1000
1001 static void acpi_ec_delete_query(struct acpi_ec_query *q)
1002 {
1003         if (q) {
1004                 if (q->handler)
1005                         acpi_ec_put_query_handler(q->handler);
1006                 kfree(q);
1007         }
1008 }
1009
1010 static void acpi_ec_event_processor(struct work_struct *work)
1011 {
1012         struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1013         struct acpi_ec_query_handler *handler = q->handler;
1014
1015         ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1016         if (handler->func)
1017                 handler->func(handler->data);
1018         else if (handler->handle)
1019                 acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1020         ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1021         acpi_ec_delete_query(q);
1022 }
1023
1024 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
1025 {
1026         u8 value = 0;
1027         int result;
1028         struct acpi_ec_query_handler *handler;
1029         struct acpi_ec_query *q;
1030
1031         q = acpi_ec_create_query(&value);
1032         if (!q)
1033                 return -ENOMEM;
1034
1035         /*
1036          * Query the EC to find out which _Qxx method we need to evaluate.
1037          * Note that successful completion of the query causes the ACPI_EC_SCI
1038          * bit to be cleared (and thus clearing the interrupt source).
1039          */
1040         result = acpi_ec_transaction(ec, &q->transaction);
1041         if (!value)
1042                 result = -ENODATA;
1043         if (result)
1044                 goto err_exit;
1045
1046         mutex_lock(&ec->mutex);
1047         list_for_each_entry(handler, &ec->list, node) {
1048                 if (value == handler->query_bit) {
1049                         q->handler = acpi_ec_get_query_handler(handler);
1050                         ec_dbg_evt("Query(0x%02x) scheduled",
1051                                    q->handler->query_bit);
1052                         /*
1053                          * It is reported that _Qxx are evaluated in a
1054                          * parallel way on Windows:
1055                          * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1056                          */
1057                         if (!schedule_work(&q->work))
1058                                 result = -EBUSY;
1059                         break;
1060                 }
1061         }
1062         mutex_unlock(&ec->mutex);
1063
1064 err_exit:
1065         if (result && q)
1066                 acpi_ec_delete_query(q);
1067         if (data)
1068                 *data = value;
1069         return result;
1070 }
1071
1072 static void acpi_ec_check_event(struct acpi_ec *ec)
1073 {
1074         unsigned long flags;
1075
1076         if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1077                 if (ec_guard(ec)) {
1078                         spin_lock_irqsave(&ec->lock, flags);
1079                         /*
1080                          * Take care of the SCI_EVT unless no one else is
1081                          * taking care of it.
1082                          */
1083                         if (!ec->curr)
1084                                 advance_transaction(ec);
1085                         spin_unlock_irqrestore(&ec->lock, flags);
1086                 }
1087         }
1088 }
1089
1090 static void acpi_ec_event_handler(struct work_struct *work)
1091 {
1092         unsigned long flags;
1093         struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1094
1095         ec_dbg_evt("Event started");
1096
1097         spin_lock_irqsave(&ec->lock, flags);
1098         while (ec->nr_pending_queries) {
1099                 spin_unlock_irqrestore(&ec->lock, flags);
1100                 (void)acpi_ec_query(ec, NULL);
1101                 spin_lock_irqsave(&ec->lock, flags);
1102                 ec->nr_pending_queries--;
1103                 /*
1104                  * Before exit, make sure that this work item can be
1105                  * scheduled again. There might be QR_EC failures, leaving
1106                  * EC_FLAGS_QUERY_PENDING uncleared and preventing this work
1107                  * item from being scheduled again.
1108                  */
1109                 if (!ec->nr_pending_queries) {
1110                         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
1111                             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY)
1112                                 acpi_ec_complete_query(ec);
1113                 }
1114         }
1115         spin_unlock_irqrestore(&ec->lock, flags);
1116
1117         ec_dbg_evt("Event stopped");
1118
1119         acpi_ec_check_event(ec);
1120 }
1121
1122 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1123         u32 gpe_number, void *data)
1124 {
1125         unsigned long flags;
1126         struct acpi_ec *ec = data;
1127
1128         spin_lock_irqsave(&ec->lock, flags);
1129         advance_transaction(ec);
1130         spin_unlock_irqrestore(&ec->lock, flags);
1131         return ACPI_INTERRUPT_HANDLED;
1132 }
1133
1134 /* --------------------------------------------------------------------------
1135  *                           Address Space Management
1136  * -------------------------------------------------------------------------- */
1137
1138 static acpi_status
1139 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1140                       u32 bits, u64 *value64,
1141                       void *handler_context, void *region_context)
1142 {
1143         struct acpi_ec *ec = handler_context;
1144         int result = 0, i, bytes = bits / 8;
1145         u8 *value = (u8 *)value64;
1146
1147         if ((address > 0xFF) || !value || !handler_context)
1148                 return AE_BAD_PARAMETER;
1149
1150         if (function != ACPI_READ && function != ACPI_WRITE)
1151                 return AE_BAD_PARAMETER;
1152
1153         if (ec_busy_polling || bits > 8)
1154                 acpi_ec_burst_enable(ec);
1155
1156         for (i = 0; i < bytes; ++i, ++address, ++value)
1157                 result = (function == ACPI_READ) ?
1158                         acpi_ec_read(ec, address, value) :
1159                         acpi_ec_write(ec, address, *value);
1160
1161         if (ec_busy_polling || bits > 8)
1162                 acpi_ec_burst_disable(ec);
1163
1164         switch (result) {
1165         case -EINVAL:
1166                 return AE_BAD_PARAMETER;
1167         case -ENODEV:
1168                 return AE_NOT_FOUND;
1169         case -ETIME:
1170                 return AE_TIME;
1171         default:
1172                 return AE_OK;
1173         }
1174 }
1175
1176 /* --------------------------------------------------------------------------
1177  *                             Driver Interface
1178  * -------------------------------------------------------------------------- */
1179
1180 static acpi_status
1181 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1182
1183 static struct acpi_ec *make_acpi_ec(void)
1184 {
1185         struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1186
1187         if (!ec)
1188                 return NULL;
1189         ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
1190         mutex_init(&ec->mutex);
1191         init_waitqueue_head(&ec->wait);
1192         INIT_LIST_HEAD(&ec->list);
1193         spin_lock_init(&ec->lock);
1194         INIT_WORK(&ec->work, acpi_ec_event_handler);
1195         ec->timestamp = jiffies;
1196         return ec;
1197 }
1198
1199 static acpi_status
1200 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1201                                void *context, void **return_value)
1202 {
1203         char node_name[5];
1204         struct acpi_buffer buffer = { sizeof(node_name), node_name };
1205         struct acpi_ec *ec = context;
1206         int value = 0;
1207         acpi_status status;
1208
1209         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1210
1211         if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1212                 acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1213         return AE_OK;
1214 }
1215
1216 static acpi_status
1217 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1218 {
1219         acpi_status status;
1220         unsigned long long tmp = 0;
1221         struct acpi_ec *ec = context;
1222
1223         /* clear addr values, ec_parse_io_ports depend on it */
1224         ec->command_addr = ec->data_addr = 0;
1225
1226         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1227                                      ec_parse_io_ports, ec);
1228         if (ACPI_FAILURE(status))
1229                 return status;
1230
1231         /* Get GPE bit assignment (EC events). */
1232         /* TODO: Add support for _GPE returning a package */
1233         status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1234         if (ACPI_FAILURE(status))
1235                 return status;
1236         ec->gpe = tmp;
1237         /* Use the global lock for all EC transactions? */
1238         tmp = 0;
1239         acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1240         ec->global_lock = tmp;
1241         ec->handle = handle;
1242         return AE_CTRL_TERMINATE;
1243 }
1244
1245 static int ec_install_handlers(struct acpi_ec *ec)
1246 {
1247         acpi_status status;
1248
1249         if (test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
1250                 return 0;
1251         status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1252                                   ACPI_GPE_EDGE_TRIGGERED,
1253                                   &acpi_ec_gpe_handler, ec);
1254         if (ACPI_FAILURE(status))
1255                 return -ENODEV;
1256
1257         acpi_ec_start(ec, false);
1258         status = acpi_install_address_space_handler(ec->handle,
1259                                                     ACPI_ADR_SPACE_EC,
1260                                                     &acpi_ec_space_handler,
1261                                                     NULL, ec);
1262         if (ACPI_FAILURE(status)) {
1263                 if (status == AE_NOT_FOUND) {
1264                         /*
1265                          * Maybe OS fails in evaluating the _REG object.
1266                          * The AE_NOT_FOUND error will be ignored and OS
1267                          * continue to initialize EC.
1268                          */
1269                         pr_err("Fail in evaluating the _REG object"
1270                                 " of EC device. Broken bios is suspected.\n");
1271                 } else {
1272                         acpi_ec_stop(ec, false);
1273                         acpi_remove_gpe_handler(NULL, ec->gpe,
1274                                 &acpi_ec_gpe_handler);
1275                         return -ENODEV;
1276                 }
1277         }
1278
1279         set_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
1280         return 0;
1281 }
1282
1283 static void ec_remove_handlers(struct acpi_ec *ec)
1284 {
1285         if (!test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
1286                 return;
1287         acpi_ec_stop(ec, false);
1288         if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1289                                 ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1290                 pr_err("failed to remove space handler\n");
1291         if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1292                                 &acpi_ec_gpe_handler)))
1293                 pr_err("failed to remove gpe handler\n");
1294         clear_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
1295 }
1296
1297 static int acpi_ec_add(struct acpi_device *device)
1298 {
1299         struct acpi_ec *ec = NULL;
1300         int ret;
1301
1302         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1303         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1304
1305         /* Check for boot EC */
1306         if (boot_ec &&
1307             (boot_ec->handle == device->handle ||
1308              boot_ec->handle == ACPI_ROOT_OBJECT)) {
1309                 ec = boot_ec;
1310                 boot_ec = NULL;
1311         } else {
1312                 ec = make_acpi_ec();
1313                 if (!ec)
1314                         return -ENOMEM;
1315         }
1316         if (ec_parse_device(device->handle, 0, ec, NULL) !=
1317                 AE_CTRL_TERMINATE) {
1318                         kfree(ec);
1319                         return -EINVAL;
1320         }
1321
1322         /* Find and register all query methods */
1323         acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1324                             acpi_ec_register_query_methods, NULL, ec, NULL);
1325
1326         if (!first_ec)
1327                 first_ec = ec;
1328         device->driver_data = ec;
1329
1330         ret = !!request_region(ec->data_addr, 1, "EC data");
1331         WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1332         ret = !!request_region(ec->command_addr, 1, "EC cmd");
1333         WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1334
1335         pr_info("GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
1336                           ec->gpe, ec->command_addr, ec->data_addr);
1337
1338         ret = ec_install_handlers(ec);
1339
1340         /* Reprobe devices depending on the EC */
1341         acpi_walk_dep_device_list(ec->handle);
1342
1343         /* EC is fully operational, allow queries */
1344         clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
1345
1346         /* Clear stale _Q events if hardware might require that */
1347         if (EC_FLAGS_CLEAR_ON_RESUME)
1348                 acpi_ec_clear(ec);
1349         return ret;
1350 }
1351
1352 static int acpi_ec_remove(struct acpi_device *device)
1353 {
1354         struct acpi_ec *ec;
1355         struct acpi_ec_query_handler *handler, *tmp;
1356
1357         if (!device)
1358                 return -EINVAL;
1359
1360         ec = acpi_driver_data(device);
1361         ec_remove_handlers(ec);
1362         mutex_lock(&ec->mutex);
1363         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1364                 list_del(&handler->node);
1365                 kfree(handler);
1366         }
1367         mutex_unlock(&ec->mutex);
1368         release_region(ec->data_addr, 1);
1369         release_region(ec->command_addr, 1);
1370         device->driver_data = NULL;
1371         if (ec == first_ec)
1372                 first_ec = NULL;
1373         kfree(ec);
1374         return 0;
1375 }
1376
1377 static acpi_status
1378 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1379 {
1380         struct acpi_ec *ec = context;
1381
1382         if (resource->type != ACPI_RESOURCE_TYPE_IO)
1383                 return AE_OK;
1384
1385         /*
1386          * The first address region returned is the data port, and
1387          * the second address region returned is the status/command
1388          * port.
1389          */
1390         if (ec->data_addr == 0)
1391                 ec->data_addr = resource->data.io.minimum;
1392         else if (ec->command_addr == 0)
1393                 ec->command_addr = resource->data.io.minimum;
1394         else
1395                 return AE_CTRL_TERMINATE;
1396
1397         return AE_OK;
1398 }
1399
1400 int __init acpi_boot_ec_enable(void)
1401 {
1402         if (!boot_ec || test_bit(EC_FLAGS_HANDLERS_INSTALLED, &boot_ec->flags))
1403                 return 0;
1404         if (!ec_install_handlers(boot_ec)) {
1405                 first_ec = boot_ec;
1406                 return 0;
1407         }
1408         return -EFAULT;
1409 }
1410
1411 static const struct acpi_device_id ec_device_ids[] = {
1412         {"PNP0C09", 0},
1413         {"", 0},
1414 };
1415
1416 /* Some BIOS do not survive early DSDT scan, skip it */
1417 static int ec_skip_dsdt_scan(const struct dmi_system_id *id)
1418 {
1419         EC_FLAGS_SKIP_DSDT_SCAN = 1;
1420         return 0;
1421 }
1422
1423 /* ASUStek often supplies us with broken ECDT, validate it */
1424 static int ec_validate_ecdt(const struct dmi_system_id *id)
1425 {
1426         EC_FLAGS_VALIDATE_ECDT = 1;
1427         return 0;
1428 }
1429
1430 #if 0
1431 /*
1432  * Some EC firmware variations refuses to respond QR_EC when SCI_EVT is not
1433  * set, for which case, we complete the QR_EC without issuing it to the
1434  * firmware.
1435  * https://bugzilla.kernel.org/show_bug.cgi?id=82611
1436  * https://bugzilla.kernel.org/show_bug.cgi?id=97381
1437  */
1438 static int ec_flag_query_handshake(const struct dmi_system_id *id)
1439 {
1440         pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
1441         EC_FLAGS_QUERY_HANDSHAKE = 1;
1442         return 0;
1443 }
1444 #endif
1445
1446 /*
1447  * On some hardware it is necessary to clear events accumulated by the EC during
1448  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1449  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1450  *
1451  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1452  *
1453  * Ideally, the EC should also be instructed NOT to accumulate events during
1454  * sleep (which Windows seems to do somehow), but the interface to control this
1455  * behaviour is not known at this time.
1456  *
1457  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1458  * however it is very likely that other Samsung models are affected.
1459  *
1460  * On systems which don't accumulate _Q events during sleep, this extra check
1461  * should be harmless.
1462  */
1463 static int ec_clear_on_resume(const struct dmi_system_id *id)
1464 {
1465         pr_debug("Detected system needing EC poll on resume.\n");
1466         EC_FLAGS_CLEAR_ON_RESUME = 1;
1467         ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1468         return 0;
1469 }
1470
1471 static struct dmi_system_id ec_dmi_table[] __initdata = {
1472         {
1473         ec_skip_dsdt_scan, "Compal JFL92", {
1474         DMI_MATCH(DMI_BIOS_VENDOR, "COMPAL"),
1475         DMI_MATCH(DMI_BOARD_NAME, "JFL92") }, NULL},
1476         {
1477         ec_validate_ecdt, "MSI MS-171F", {
1478         DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1479         DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
1480         {
1481         ec_validate_ecdt, "ASUS hardware", {
1482         DMI_MATCH(DMI_BIOS_VENDOR, "ASUS") }, NULL},
1483         {
1484         ec_validate_ecdt, "ASUS hardware", {
1485         DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer Inc.") }, NULL},
1486         {
1487         ec_skip_dsdt_scan, "HP Folio 13", {
1488         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
1489         DMI_MATCH(DMI_PRODUCT_NAME, "HP Folio 13"),}, NULL},
1490         {
1491         ec_validate_ecdt, "ASUS hardware", {
1492         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTek Computer Inc."),
1493         DMI_MATCH(DMI_PRODUCT_NAME, "L4R"),}, NULL},
1494         {
1495         ec_clear_on_resume, "Samsung hardware", {
1496         DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1497         {},
1498 };
1499
1500 int __init acpi_ec_ecdt_probe(void)
1501 {
1502         acpi_status status;
1503         struct acpi_ec *saved_ec = NULL;
1504         struct acpi_table_ecdt *ecdt_ptr;
1505
1506         boot_ec = make_acpi_ec();
1507         if (!boot_ec)
1508                 return -ENOMEM;
1509         /*
1510          * Generate a boot ec context
1511          */
1512         dmi_check_system(ec_dmi_table);
1513         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1514                                 (struct acpi_table_header **)&ecdt_ptr);
1515         if (ACPI_SUCCESS(status)) {
1516                 pr_info("EC description table is found, configuring boot EC\n");
1517                 boot_ec->command_addr = ecdt_ptr->control.address;
1518                 boot_ec->data_addr = ecdt_ptr->data.address;
1519                 boot_ec->gpe = ecdt_ptr->gpe;
1520                 boot_ec->handle = ACPI_ROOT_OBJECT;
1521                 acpi_get_handle(ACPI_ROOT_OBJECT, ecdt_ptr->id,
1522                                 &boot_ec->handle);
1523                 /* Don't trust ECDT, which comes from ASUSTek */
1524                 if (!EC_FLAGS_VALIDATE_ECDT)
1525                         goto install;
1526                 saved_ec = kmemdup(boot_ec, sizeof(struct acpi_ec), GFP_KERNEL);
1527                 if (!saved_ec)
1528                         return -ENOMEM;
1529         /* fall through */
1530         }
1531
1532         if (EC_FLAGS_SKIP_DSDT_SCAN) {
1533                 kfree(saved_ec);
1534                 return -ENODEV;
1535         }
1536
1537         /* This workaround is needed only on some broken machines,
1538          * which require early EC, but fail to provide ECDT */
1539         pr_debug("Look up EC in DSDT\n");
1540         status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device,
1541                                         boot_ec, NULL);
1542         /* Check that acpi_get_devices actually find something */
1543         if (ACPI_FAILURE(status) || !boot_ec->handle)
1544                 goto error;
1545         if (saved_ec) {
1546                 /* try to find good ECDT from ASUSTek */
1547                 if (saved_ec->command_addr != boot_ec->command_addr ||
1548                     saved_ec->data_addr != boot_ec->data_addr ||
1549                     saved_ec->gpe != boot_ec->gpe ||
1550                     saved_ec->handle != boot_ec->handle)
1551                         pr_info("ASUSTek keeps feeding us with broken "
1552                         "ECDT tables, which are very hard to workaround. "
1553                         "Trying to use DSDT EC info instead. Please send "
1554                         "output of acpidump to [email protected]\n");
1555                 kfree(saved_ec);
1556                 saved_ec = NULL;
1557         } else {
1558                 /* We really need to limit this workaround, the only ASUS,
1559                 * which needs it, has fake EC._INI method, so use it as flag.
1560                 * Keep boot_ec struct as it will be needed soon.
1561                 */
1562                 if (!dmi_name_in_vendors("ASUS") ||
1563                     !acpi_has_method(boot_ec->handle, "_INI"))
1564                         return -ENODEV;
1565         }
1566 install:
1567         if (!ec_install_handlers(boot_ec)) {
1568                 first_ec = boot_ec;
1569                 return 0;
1570         }
1571 error:
1572         kfree(boot_ec);
1573         kfree(saved_ec);
1574         boot_ec = NULL;
1575         return -ENODEV;
1576 }
1577
1578 static int param_set_event_clearing(const char *val, struct kernel_param *kp)
1579 {
1580         int result = 0;
1581
1582         if (!strncmp(val, "status", sizeof("status") - 1)) {
1583                 ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1584                 pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
1585         } else if (!strncmp(val, "query", sizeof("query") - 1)) {
1586                 ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
1587                 pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
1588         } else if (!strncmp(val, "event", sizeof("event") - 1)) {
1589                 ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
1590                 pr_info("Assuming SCI_EVT clearing on event reads\n");
1591         } else
1592                 result = -EINVAL;
1593         return result;
1594 }
1595
1596 static int param_get_event_clearing(char *buffer, struct kernel_param *kp)
1597 {
1598         switch (ec_event_clearing) {
1599         case ACPI_EC_EVT_TIMING_STATUS:
1600                 return sprintf(buffer, "status");
1601         case ACPI_EC_EVT_TIMING_QUERY:
1602                 return sprintf(buffer, "query");
1603         case ACPI_EC_EVT_TIMING_EVENT:
1604                 return sprintf(buffer, "event");
1605         default:
1606                 return sprintf(buffer, "invalid");
1607         }
1608         return 0;
1609 }
1610
1611 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
1612                   NULL, 0644);
1613 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
1614
1615 static struct acpi_driver acpi_ec_driver = {
1616         .name = "ec",
1617         .class = ACPI_EC_CLASS,
1618         .ids = ec_device_ids,
1619         .ops = {
1620                 .add = acpi_ec_add,
1621                 .remove = acpi_ec_remove,
1622                 },
1623 };
1624
1625 int __init acpi_ec_init(void)
1626 {
1627         int result = 0;
1628
1629         /* Now register the driver for the EC */
1630         result = acpi_bus_register_driver(&acpi_ec_driver);
1631         if (result < 0)
1632                 return -ENODEV;
1633
1634         return result;
1635 }
1636
1637 /* EC driver currently not unloadable */
1638 #if 0
1639 static void __exit acpi_ec_exit(void)
1640 {
1641
1642         acpi_bus_unregister_driver(&acpi_ec_driver);
1643 }
1644 #endif  /* 0 */