kernel/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_PENDING,         /* Query is pending */
 108         EC_FLAGS_QUERY_GUARDING,        /* Guard for SCI_EVT check */
 109         EC_FLAGS_HANDLERS_INSTALLED,    /* Handlers for GPE and
 110                                          * OpReg are installed */
 111         EC_FLAGS_STARTED,               /* Driver is started */
 112         EC_FLAGS_STOPPED,               /* Driver is stopped */
 113         EC_FLAGS_COMMAND_STORM,         /* GPE storms occurred to the
 114                                          * current command processing */
 115 };
 116
 117 #define ACPI_EC_COMMAND_POLL            0x01 /* Available for command byte */
 118 #define ACPI_EC_COMMAND_COMPLETE        0x02 /* Completed last byte */
 119
 120 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
 121 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
 122 module_param(ec_delay, uint, 0644);
 123 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
 124
 125 static unsigned int ec_max_queries __read_mostly = ACPI_EC_MAX_QUERIES;
 126 module_param(ec_max_queries, uint, 0644);
 127 MODULE_PARM_DESC(ec_max_queries, "Maximum parallel _Qxx evaluations");
 128
 129 static bool ec_busy_polling __read_mostly;
 130 module_param(ec_busy_polling, bool, 0644);
 131 MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction");
 132
 133 static unsigned int ec_polling_guard __read_mostly = ACPI_EC_UDELAY_POLL;
 134 module_param(ec_polling_guard, uint, 0644);
 135 MODULE_PARM_DESC(ec_polling_guard, "Guard time(us) between EC accesses in polling modes");
 136
 137 static unsigned int ec_event_clearing __read_mostly = ACPI_EC_EVT_TIMING_QUERY;
 138
 139 /*
 140  * If the number of false interrupts per one transaction exceeds
 141  * this threshold, will think there is a GPE storm happened and
 142  * will disable the GPE for normal transaction.
 143  */
 144 static unsigned int ec_storm_threshold  __read_mostly = 8;
 145 module_param(ec_storm_threshold, uint, 0644);
 146 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
 147
 148 struct acpi_ec_query_handler {
 149         struct list_head node;
 150         acpi_ec_query_func func;
 151         acpi_handle handle;
 152         void *data;
 153         u8 query_bit;
 154         struct kref kref;
 155 };
 156
 157 struct transaction {
 158         const u8 *wdata;
 159         u8 *rdata;
 160         unsigned short irq_count;
 161         u8 command;
 162         u8 wi;
 163         u8 ri;
 164         u8 wlen;
 165         u8 rlen;
 166         u8 flags;
 167 };
 168
 169 struct acpi_ec_query {
 170         struct transaction transaction;
 171         struct work_struct work;
 172         struct acpi_ec_query_handler *handler;
 173 };
 174
 175 static int acpi_ec_query(struct acpi_ec *ec, u8 *data);
 176 static void advance_transaction(struct acpi_ec *ec);
 177 static void acpi_ec_event_handler(struct work_struct *work);
 178 static void acpi_ec_event_processor(struct work_struct *work);
 179
 180 struct acpi_ec *boot_ec, *first_ec;
 181 EXPORT_SYMBOL(first_ec);
 182 static struct workqueue_struct *ec_query_wq;
 183
 184 static int EC_FLAGS_VALIDATE_ECDT; /* ASUStec ECDTs need to be validated */
 185 static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
 186 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
 187 static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
 188
 189 /* --------------------------------------------------------------------------
 190  *                           Logging/Debugging
 191  * -------------------------------------------------------------------------- */
 192
 193 /*
 194  * Splitters used by the developers to track the boundary of the EC
 195  * handling processes.
 196  */
 197 #ifdef DEBUG
 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 #else
 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 #endif
 210
 211 #define ec_log_raw(fmt, ...) \
 212         pr_info(fmt "\n", ##__VA_ARGS__)
 213 #define ec_dbg_raw(fmt, ...) \
 214         pr_debug(fmt "\n", ##__VA_ARGS__)
 215 #define ec_log(filter, fmt, ...) \
 216         ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
 217 #define ec_dbg(filter, fmt, ...) \
 218         ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
 219
 220 #define ec_log_drv(fmt, ...) \
 221         ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
 222 #define ec_dbg_drv(fmt, ...) \
 223         ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
 224 #define ec_dbg_stm(fmt, ...) \
 225         ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
 226 #define ec_dbg_req(fmt, ...) \
 227         ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
 228 #define ec_dbg_evt(fmt, ...) \
 229         ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
 230 #define ec_dbg_ref(ec, fmt, ...) \
 231         ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
 232
 233 /* --------------------------------------------------------------------------
 234  *                           Device Flags
 235  * -------------------------------------------------------------------------- */
 236
 237 static bool acpi_ec_started(struct acpi_ec *ec)
 238 {
 239         return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
 240                !test_bit(EC_FLAGS_STOPPED, &ec->flags);
 241 }
 242
 243 static bool acpi_ec_flushed(struct acpi_ec *ec)
 244 {
 245         return ec->reference_count == 1;
 246 }
 247
 248 /* --------------------------------------------------------------------------
 249  *                           EC Registers
 250  * -------------------------------------------------------------------------- */
 251
 252 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
 253 {
 254         u8 x = inb(ec->command_addr);
 255
 256         ec_dbg_raw("EC_SC(R) = 0x%2.2x "
 257                    "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
 258                    x,
 259                    !!(x & ACPI_EC_FLAG_SCI),
 260                    !!(x & ACPI_EC_FLAG_BURST),
 261                    !!(x & ACPI_EC_FLAG_CMD),
 262                    !!(x & ACPI_EC_FLAG_IBF),
 263                    !!(x & ACPI_EC_FLAG_OBF));
 264         return x;
 265 }
 266
 267 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
 268 {
 269         u8 x = inb(ec->data_addr);
 270
 271         ec->timestamp = jiffies;
 272         ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
 273         return x;
 274 }
 275
 276 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
 277 {
 278         ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
 279         outb(command, ec->command_addr);
 280         ec->timestamp = jiffies;
 281 }
 282
 283 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
 284 {
 285         ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
 286         outb(data, ec->data_addr);
 287         ec->timestamp = jiffies;
 288 }
 289
 290 #ifdef DEBUG
 291 static const char *acpi_ec_cmd_string(u8 cmd)
 292 {
 293         switch (cmd) {
 294         case 0x80:
 295                 return "RD_EC";
 296         case 0x81:
 297                 return "WR_EC";
 298         case 0x82:
 299                 return "BE_EC";
 300         case 0x83:
 301                 return "BD_EC";
 302         case 0x84:
 303                 return "QR_EC";
 304         }
 305         return "UNKNOWN";
 306 }
 307 #else
 308 #define acpi_ec_cmd_string(cmd)         "UNDEF"
 309 #endif
 310
 311 /* --------------------------------------------------------------------------
 312  *                           GPE Registers
 313  * -------------------------------------------------------------------------- */
 314
 315 static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec)
 316 {
 317         acpi_event_status gpe_status = 0;
 318
 319         (void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
 320         return (gpe_status & ACPI_EVENT_FLAG_STATUS_SET) ? true : false;
 321 }
 322
 323 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
 324 {
 325         if (open)
 326                 acpi_enable_gpe(NULL, ec->gpe);
 327         else {
 328                 BUG_ON(ec->reference_count < 1);
 329                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
 330         }
 331         if (acpi_ec_is_gpe_raised(ec)) {
 332                 /*
 333                  * On some platforms, EN=1 writes cannot trigger GPE. So
 334                  * software need to manually trigger a pseudo GPE event on
 335                  * EN=1 writes.
 336                  */
 337                 ec_dbg_raw("Polling quirk");
 338                 advance_transaction(ec);
 339         }
 340 }
 341
 342 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
 343 {
 344         if (close)
 345                 acpi_disable_gpe(NULL, ec->gpe);
 346         else {
 347                 BUG_ON(ec->reference_count < 1);
 348                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
 349         }
 350 }
 351
 352 static inline void acpi_ec_clear_gpe(struct acpi_ec *ec)
 353 {
 354         /*
 355          * GPE STS is a W1C register, which means:
 356          * 1. Software can clear it without worrying about clearing other
 357          *    GPEs' STS bits when the hardware sets them in parallel.
 358          * 2. As long as software can ensure only clearing it when it is
 359          *    set, hardware won't set it in parallel.
 360          * So software can clear GPE in any contexts.
 361          * Warning: do not move the check into advance_transaction() as the
 362          * EC commands will be sent without GPE raised.
 363          */
 364         if (!acpi_ec_is_gpe_raised(ec))
 365                 return;
 366         acpi_clear_gpe(NULL, ec->gpe);
 367 }
 368
 369 /* --------------------------------------------------------------------------
 370  *                           Transaction Management
 371  * -------------------------------------------------------------------------- */
 372
 373 static void acpi_ec_submit_request(struct acpi_ec *ec)
 374 {
 375         ec->reference_count++;
 376         if (ec->reference_count == 1)
 377                 acpi_ec_enable_gpe(ec, true);
 378 }
 379
 380 static void acpi_ec_complete_request(struct acpi_ec *ec)
 381 {
 382         bool flushed = false;
 383
 384         ec->reference_count--;
 385         if (ec->reference_count == 0)
 386                 acpi_ec_disable_gpe(ec, true);
 387         flushed = acpi_ec_flushed(ec);
 388         if (flushed)
 389                 wake_up(&ec->wait);
 390 }
 391
 392 static void acpi_ec_set_storm(struct acpi_ec *ec, u8 flag)
 393 {
 394         if (!test_bit(flag, &ec->flags)) {
 395                 acpi_ec_disable_gpe(ec, false);
 396                 ec_dbg_drv("Polling enabled");
 397                 set_bit(flag, &ec->flags);
 398         }
 399 }
 400
 401 static void acpi_ec_clear_storm(struct acpi_ec *ec, u8 flag)
 402 {
 403         if (test_bit(flag, &ec->flags)) {
 404                 clear_bit(flag, &ec->flags);
 405                 acpi_ec_enable_gpe(ec, false);
 406                 ec_dbg_drv("Polling disabled");
 407         }
 408 }
 409
 410 /*
 411  * acpi_ec_submit_flushable_request() - Increase the reference count unless
 412  *                                      the flush operation is not in
 413  *                                      progress
 414  * @ec: the EC device
 415  *
 416  * This function must be used before taking a new action that should hold
 417  * the reference count.  If this function returns false, then the action
 418  * must be discarded or it will prevent the flush operation from being
 419  * completed.
 420  */
 421 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
 422 {
 423         if (!acpi_ec_started(ec))
 424                 return false;
 425         acpi_ec_submit_request(ec);
 426         return true;
 427 }
 428
 429 static void acpi_ec_submit_query(struct acpi_ec *ec)
 430 {
 431         if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
 432                 ec_dbg_evt("Command(%s) submitted/blocked",
 433                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 434                 ec->nr_pending_queries++;
 435                 schedule_work(&ec->work);
 436         }
 437 }
 438
 439 static void acpi_ec_complete_query(struct acpi_ec *ec)
 440 {
 441         if (test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
 442                 clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
 443                 ec_dbg_evt("Command(%s) unblocked",
 444                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 445         }
 446 }
 447
 448 static bool acpi_ec_guard_event(struct acpi_ec *ec)
 449 {
 450         bool guarded = true;
 451         unsigned long flags;
 452
 453         spin_lock_irqsave(&ec->lock, flags);
 454         /*
 455          * If firmware SCI_EVT clearing timing is "event", we actually
 456          * don't know when the SCI_EVT will be cleared by firmware after
 457          * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
 458          * acceptable period.
 459          *
 460          * The guarding period begins when EC_FLAGS_QUERY_PENDING is
 461          * flagged, which means SCI_EVT check has just been performed.
 462          * But if the current transaction is ACPI_EC_COMMAND_QUERY, the
 463          * guarding should have already been performed (via
 464          * EC_FLAGS_QUERY_GUARDING) and should not be applied so that the
 465          * ACPI_EC_COMMAND_QUERY transaction can be transitioned into
 466          * ACPI_EC_COMMAND_POLL state immediately.
 467          */
 468         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
 469             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY ||
 470             !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) ||
 471             (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY))
 472                 guarded = false;
 473         spin_unlock_irqrestore(&ec->lock, flags);
 474         return guarded;
 475 }
 476
 477 static int ec_transaction_polled(struct acpi_ec *ec)
 478 {
 479         unsigned long flags;
 480         int ret = 0;
 481
 482         spin_lock_irqsave(&ec->lock, flags);
 483         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
 484                 ret = 1;
 485         spin_unlock_irqrestore(&ec->lock, flags);
 486         return ret;
 487 }
 488
 489 static int ec_transaction_completed(struct acpi_ec *ec)
 490 {
 491         unsigned long flags;
 492         int ret = 0;
 493
 494         spin_lock_irqsave(&ec->lock, flags);
 495         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
 496                 ret = 1;
 497         spin_unlock_irqrestore(&ec->lock, flags);
 498         return ret;
 499 }
 500
 501 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
 502 {
 503         ec->curr->flags |= flag;
 504         if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
 505                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS &&
 506                     flag == ACPI_EC_COMMAND_POLL)
 507                         acpi_ec_complete_query(ec);
 508                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY &&
 509                     flag == ACPI_EC_COMMAND_COMPLETE)
 510                         acpi_ec_complete_query(ec);
 511                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 512                     flag == ACPI_EC_COMMAND_COMPLETE)
 513                         set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
 514         }
 515 }
 516
 517 static void advance_transaction(struct acpi_ec *ec)
 518 {
 519         struct transaction *t;
 520         u8 status;
 521         bool wakeup = false;
 522
 523         ec_dbg_stm("%s (%d)", in_interrupt() ? "IRQ" : "TASK",
 524                    smp_processor_id());
 525         /*
 526          * By always clearing STS before handling all indications, we can
 527          * ensure a hardware STS 0->1 change after this clearing can always
 528          * trigger a GPE interrupt.
 529          */
 530         acpi_ec_clear_gpe(ec);
 531         status = acpi_ec_read_status(ec);
 532         t = ec->curr;
 533         /*
 534          * Another IRQ or a guarded polling mode advancement is detected,
 535          * the next QR_EC submission is then allowed.
 536          */
 537         if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
 538                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 539                     (!ec->nr_pending_queries ||
 540                      test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) {
 541                         clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
 542                         acpi_ec_complete_query(ec);
 543                 }
 544         }
 545         if (!t)
 546                 goto err;
 547         if (t->flags & ACPI_EC_COMMAND_POLL) {
 548                 if (t->wlen > t->wi) {
 549                         if ((status & ACPI_EC_FLAG_IBF) == 0)
 550                                 acpi_ec_write_data(ec, t->wdata[t->wi++]);
 551                         else
 552                                 goto err;
 553                 } else if (t->rlen > t->ri) {
 554                         if ((status & ACPI_EC_FLAG_OBF) == 1) {
 555                                 t->rdata[t->ri++] = acpi_ec_read_data(ec);
 556                                 if (t->rlen == t->ri) {
 557                                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 558                                         if (t->command == ACPI_EC_COMMAND_QUERY)
 559                                                 ec_dbg_evt("Command(%s) completed by hardware",
 560                                                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 561                                         wakeup = true;
 562                                 }
 563                         } else
 564                                 goto err;
 565                 } else if (t->wlen == t->wi &&
 566                            (status & ACPI_EC_FLAG_IBF) == 0) {
 567                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 568                         wakeup = true;
 569                 }
 570                 goto out;
 571         } else {
 572                 if (EC_FLAGS_QUERY_HANDSHAKE &&
 573                     !(status & ACPI_EC_FLAG_SCI) &&
 574                     (t->command == ACPI_EC_COMMAND_QUERY)) {
 575                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
 576                         t->rdata[t->ri++] = 0x00;
 577                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 578                         ec_dbg_evt("Command(%s) completed by software",
 579                                    acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 580                         wakeup = true;
 581                 } else if ((status & ACPI_EC_FLAG_IBF) == 0) {
 582                         acpi_ec_write_cmd(ec, t->command);
 583                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
 584                 } else
 585                         goto err;
 586                 goto out;
 587         }
 588 err:
 589         /*
 590          * If SCI bit is set, then don't think it's a false IRQ
 591          * otherwise will take a not handled IRQ as a false one.
 592          */
 593         if (!(status & ACPI_EC_FLAG_SCI)) {
 594                 if (in_interrupt() && t) {
 595                         if (t->irq_count < ec_storm_threshold)
 596                                 ++t->irq_count;
 597                         /* Allow triggering on 0 threshold */
 598                         if (t->irq_count == ec_storm_threshold)
 599                                 acpi_ec_set_storm(ec, EC_FLAGS_COMMAND_STORM);
 600                 }
 601         }
 602 out:
 603         if (status & ACPI_EC_FLAG_SCI)
 604                 acpi_ec_submit_query(ec);
 605         if (wakeup && in_interrupt())
 606                 wake_up(&ec->wait);
 607 }
 608
 609 static void start_transaction(struct acpi_ec *ec)
 610 {
 611         ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
 612         ec->curr->flags = 0;
 613 }
 614
 615 static int ec_guard(struct acpi_ec *ec)
 616 {
 617         unsigned long guard = usecs_to_jiffies(ec_polling_guard);
 618         unsigned long timeout = ec->timestamp + guard;
 619
 620         /* Ensure guarding period before polling EC status */
 621         do {
 622                 if (ec_busy_polling) {
 623                         /* Perform busy polling */
 624                         if (ec_transaction_completed(ec))
 625                                 return 0;
 626                         udelay(jiffies_to_usecs(guard));
 627                 } else {
 628                         /*
 629                          * Perform wait polling
 630                          * 1. Wait the transaction to be completed by the
 631                          *    GPE handler after the transaction enters
 632                          *    ACPI_EC_COMMAND_POLL state.
 633                          * 2. A special guarding logic is also required
 634                          *    for event clearing mode "event" before the
 635                          *    transaction enters ACPI_EC_COMMAND_POLL
 636                          *    state.
 637                          */
 638                         if (!ec_transaction_polled(ec) &&
 639                             !acpi_ec_guard_event(ec))
 640                                 break;
 641                         if (wait_event_timeout(ec->wait,
 642                                                ec_transaction_completed(ec),
 643                                                guard))
 644                                 return 0;
 645                 }
 646         } while (time_before(jiffies, timeout));
 647         return -ETIME;
 648 }
 649
 650 static int ec_poll(struct acpi_ec *ec)
 651 {
 652         unsigned long flags;
 653         int repeat = 5; /* number of command restarts */
 654
 655         while (repeat--) {
 656                 unsigned long delay = jiffies +
 657                         msecs_to_jiffies(ec_delay);
 658                 do {
 659                         if (!ec_guard(ec))
 660                                 return 0;
 661                         spin_lock_irqsave(&ec->lock, flags);
 662                         advance_transaction(ec);
 663                         spin_unlock_irqrestore(&ec->lock, flags);
 664                 } while (time_before(jiffies, delay));
 665                 pr_debug("controller reset, restart transaction\n");
 666                 spin_lock_irqsave(&ec->lock, flags);
 667                 start_transaction(ec);
 668                 spin_unlock_irqrestore(&ec->lock, flags);
 669         }
 670         return -ETIME;
 671 }
 672
 673 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
 674                                         struct transaction *t)
 675 {
 676         unsigned long tmp;
 677         int ret = 0;
 678
 679         /* start transaction */
 680         spin_lock_irqsave(&ec->lock, tmp);
 681         /* Enable GPE for command processing (IBF=0/OBF=1) */
 682         if (!acpi_ec_submit_flushable_request(ec)) {
 683                 ret = -EINVAL;
 684                 goto unlock;
 685         }
 686         ec_dbg_ref(ec, "Increase command");
 687         /* following two actions should be kept atomic */
 688         ec->curr = t;
 689         ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
 690         start_transaction(ec);
 691         spin_unlock_irqrestore(&ec->lock, tmp);
 692
 693         ret = ec_poll(ec);
 694
 695         spin_lock_irqsave(&ec->lock, tmp);
 696         if (t->irq_count == ec_storm_threshold)
 697                 acpi_ec_clear_storm(ec, EC_FLAGS_COMMAND_STORM);
 698         ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
 699         ec->curr = NULL;
 700         /* Disable GPE for command processing (IBF=0/OBF=1) */
 701         acpi_ec_complete_request(ec);
 702         ec_dbg_ref(ec, "Decrease command");
 703 unlock:
 704         spin_unlock_irqrestore(&ec->lock, tmp);
 705         return ret;
 706 }
 707
 708 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
 709 {
 710         int status;
 711         u32 glk;
 712
 713         if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
 714                 return -EINVAL;
 715         if (t->rdata)
 716                 memset(t->rdata, 0, t->rlen);
 717
 718         mutex_lock(&ec->mutex);
 719         if (ec->global_lock) {
 720                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
 721                 if (ACPI_FAILURE(status)) {
 722                         status = -ENODEV;
 723                         goto unlock;
 724                 }
 725         }
 726
 727         status = acpi_ec_transaction_unlocked(ec, t);
 728
 729         if (ec->global_lock)
 730                 acpi_release_global_lock(glk);
 731 unlock:
 732         mutex_unlock(&ec->mutex);
 733         return status;
 734 }
 735
 736 static int acpi_ec_burst_enable(struct acpi_ec *ec)
 737 {
 738         u8 d;
 739         struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
 740                                 .wdata = NULL, .rdata = &d,
 741                                 .wlen = 0, .rlen = 1};
 742
 743         return acpi_ec_transaction(ec, &t);
 744 }
 745
 746 static int acpi_ec_burst_disable(struct acpi_ec *ec)
 747 {
 748         struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
 749                                 .wdata = NULL, .rdata = NULL,
 750                                 .wlen = 0, .rlen = 0};
 751
 752         return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
 753                                 acpi_ec_transaction(ec, &t) : 0;
 754 }
 755
 756 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
 757 {
 758         int result;
 759         u8 d;
 760         struct transaction t = {.command = ACPI_EC_COMMAND_READ,
 761                                 .wdata = &address, .rdata = &d,
 762                                 .wlen = 1, .rlen = 1};
 763
 764         result = acpi_ec_transaction(ec, &t);
 765         *data = d;
 766         return result;
 767 }
 768
 769 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
 770 {
 771         u8 wdata[2] = { address, data };
 772         struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
 773                                 .wdata = wdata, .rdata = NULL,
 774                                 .wlen = 2, .rlen = 0};
 775
 776         return acpi_ec_transaction(ec, &t);
 777 }
 778
 779 int ec_read(u8 addr, u8 *val)
 780 {
 781         int err;
 782         u8 temp_data;
 783
 784         if (!first_ec)
 785                 return -ENODEV;
 786
 787         err = acpi_ec_read(first_ec, addr, &temp_data);
 788
 789         if (!err) {
 790                 *val = temp_data;
 791                 return 0;
 792         }
 793         return err;
 794 }
 795 EXPORT_SYMBOL(ec_read);
 796
 797 int ec_write(u8 addr, u8 val)
 798 {
 799         int err;
 800
 801         if (!first_ec)
 802                 return -ENODEV;
 803
 804         err = acpi_ec_write(first_ec, addr, val);
 805
 806         return err;
 807 }
 808 EXPORT_SYMBOL(ec_write);
 809
 810 int ec_transaction(u8 command,
 811                    const u8 *wdata, unsigned wdata_len,
 812                    u8 *rdata, unsigned rdata_len)
 813 {
 814         struct transaction t = {.command = command,
 815                                 .wdata = wdata, .rdata = rdata,
 816                                 .wlen = wdata_len, .rlen = rdata_len};
 817
 818         if (!first_ec)
 819                 return -ENODEV;
 820
 821         return acpi_ec_transaction(first_ec, &t);
 822 }
 823 EXPORT_SYMBOL(ec_transaction);
 824
 825 /* Get the handle to the EC device */
 826 acpi_handle ec_get_handle(void)
 827 {
 828         if (!first_ec)
 829                 return NULL;
 830         return first_ec->handle;
 831 }
 832 EXPORT_SYMBOL(ec_get_handle);
 833
 834 /*
 835  * Process _Q events that might have accumulated in the EC.
 836  * Run with locked ec mutex.
 837  */
 838 static void acpi_ec_clear(struct acpi_ec *ec)
 839 {
 840         int i, status;
 841         u8 value = 0;
 842
 843         for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
 844                 status = acpi_ec_query(ec, &value);
 845                 if (status || !value)
 846                         break;
 847         }
 848
 849         if (unlikely(i == ACPI_EC_CLEAR_MAX))
 850                 pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
 851         else
 852                 pr_info("%d stale EC events cleared\n", i);
 853 }
 854
 855 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
 856 {
 857         unsigned long flags;
 858
 859         spin_lock_irqsave(&ec->lock, flags);
 860         if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
 861                 ec_dbg_drv("Starting EC");
 862                 /* Enable GPE for event processing (SCI_EVT=1) */
 863                 if (!resuming) {
 864                         acpi_ec_submit_request(ec);
 865                         ec_dbg_ref(ec, "Increase driver");
 866                 }
 867                 ec_log_drv("EC started");
 868         }
 869         spin_unlock_irqrestore(&ec->lock, flags);
 870 }
 871
 872 static bool acpi_ec_stopped(struct acpi_ec *ec)
 873 {
 874         unsigned long flags;
 875         bool flushed;
 876
 877         spin_lock_irqsave(&ec->lock, flags);
 878         flushed = acpi_ec_flushed(ec);
 879         spin_unlock_irqrestore(&ec->lock, flags);
 880         return flushed;
 881 }
 882
 883 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
 884 {
 885         unsigned long flags;
 886
 887         spin_lock_irqsave(&ec->lock, flags);
 888         if (acpi_ec_started(ec)) {
 889                 ec_dbg_drv("Stopping EC");
 890                 set_bit(EC_FLAGS_STOPPED, &ec->flags);
 891                 spin_unlock_irqrestore(&ec->lock, flags);
 892                 wait_event(ec->wait, acpi_ec_stopped(ec));
 893                 spin_lock_irqsave(&ec->lock, flags);
 894                 /* Disable GPE for event processing (SCI_EVT=1) */
 895                 if (!suspending) {
 896                         acpi_ec_complete_request(ec);
 897                         ec_dbg_ref(ec, "Decrease driver");
 898                 }
 899                 clear_bit(EC_FLAGS_STARTED, &ec->flags);
 900                 clear_bit(EC_FLAGS_STOPPED, &ec->flags);
 901                 ec_log_drv("EC stopped");
 902         }
 903         spin_unlock_irqrestore(&ec->lock, flags);
 904 }
 905
 906 void acpi_ec_block_transactions(void)
 907 {
 908         struct acpi_ec *ec = first_ec;
 909
 910         if (!ec)
 911                 return;
 912
 913         mutex_lock(&ec->mutex);
 914         /* Prevent transactions from being carried out */
 915         acpi_ec_stop(ec, true);
 916         mutex_unlock(&ec->mutex);
 917 }
 918
 919 void acpi_ec_unblock_transactions(void)
 920 {
 921         struct acpi_ec *ec = first_ec;
 922
 923         if (!ec)
 924                 return;
 925
 926         /* Allow transactions to be carried out again */
 927         acpi_ec_start(ec, true);
 928
 929         if (EC_FLAGS_CLEAR_ON_RESUME)
 930                 acpi_ec_clear(ec);
 931 }
 932
 933 void acpi_ec_unblock_transactions_early(void)
 934 {
 935         /*
 936          * Allow transactions to happen again (this function is called from
 937          * atomic context during wakeup, so we don't need to acquire the mutex).
 938          */
 939         if (first_ec)
 940                 acpi_ec_start(first_ec, true);
 941 }
 942
 943 /* --------------------------------------------------------------------------
 944                                 Event Management
 945    -------------------------------------------------------------------------- */
 946 static struct acpi_ec_query_handler *
 947 acpi_ec_get_query_handler(struct acpi_ec_query_handler *handler)
 948 {
 949         if (handler)
 950                 kref_get(&handler->kref);
 951         return handler;
 952 }
 953
 954 static struct acpi_ec_query_handler *
 955 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
 956 {
 957         struct acpi_ec_query_handler *handler;
 958         bool found = false;
 959
 960         mutex_lock(&ec->mutex);
 961         list_for_each_entry(handler, &ec->list, node) {
 962                 if (value == handler->query_bit) {
 963                         found = true;
 964                         break;
 965                 }
 966         }
 967         mutex_unlock(&ec->mutex);
 968         return found ? acpi_ec_get_query_handler(handler) : NULL;
 969 }
 970
 971 static void acpi_ec_query_handler_release(struct kref *kref)
 972 {
 973         struct acpi_ec_query_handler *handler =
 974                 container_of(kref, struct acpi_ec_query_handler, kref);
 975
 976         kfree(handler);
 977 }
 978
 979 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
 980 {
 981         kref_put(&handler->kref, acpi_ec_query_handler_release);
 982 }
 983
 984 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
 985                               acpi_handle handle, acpi_ec_query_func func,
 986                               void *data)
 987 {
 988         struct acpi_ec_query_handler *handler =
 989             kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
 990
 991         if (!handler)
 992                 return -ENOMEM;
 993
 994         handler->query_bit = query_bit;
 995         handler->handle = handle;
 996         handler->func = func;
 997         handler->data = data;
 998         mutex_lock(&ec->mutex);
 999         kref_init(&handler->kref);
1000         list_add(&handler->node, &ec->list);
1001         mutex_unlock(&ec->mutex);
1002         return 0;
1003 }
1004 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1005
1006 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1007                                           bool remove_all, u8 query_bit)
1008 {
1009         struct acpi_ec_query_handler *handler, *tmp;
1010         LIST_HEAD(free_list);
1011
1012         mutex_lock(&ec->mutex);
1013         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1014                 if (remove_all || query_bit == handler->query_bit) {
1015                         list_del_init(&handler->node);
1016                         list_add(&handler->node, &free_list);
1017                 }
1018         }
1019         mutex_unlock(&ec->mutex);
1020         list_for_each_entry_safe(handler, tmp, &free_list, node)
1021                 acpi_ec_put_query_handler(handler);
1022 }
1023
1024 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1025 {
1026         acpi_ec_remove_query_handlers(ec, false, query_bit);
1027 }
1028 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1029
1030 static struct acpi_ec_query *acpi_ec_create_query(u8 *pval)
1031 {
1032         struct acpi_ec_query *q;
1033         struct transaction *t;
1034
1035         q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1036         if (!q)
1037                 return NULL;
1038         INIT_WORK(&q->work, acpi_ec_event_processor);
1039         t = &q->transaction;
1040         t->command = ACPI_EC_COMMAND_QUERY;
1041         t->rdata = pval;
1042         t->rlen = 1;
1043         return q;
1044 }
1045
1046 static void acpi_ec_delete_query(struct acpi_ec_query *q)
1047 {
1048         if (q) {
1049                 if (q->handler)
1050                         acpi_ec_put_query_handler(q->handler);
1051                 kfree(q);
1052         }
1053 }
1054
1055 static void acpi_ec_event_processor(struct work_struct *work)
1056 {
1057         struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1058         struct acpi_ec_query_handler *handler = q->handler;
1059
1060         ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1061         if (handler->func)
1062                 handler->func(handler->data);
1063         else if (handler->handle)
1064                 acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1065         ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1066         acpi_ec_delete_query(q);
1067 }
1068
1069 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
1070 {
1071         u8 value = 0;
1072         int result;
1073         struct acpi_ec_query *q;
1074
1075         q = acpi_ec_create_query(&value);
1076         if (!q)
1077                 return -ENOMEM;
1078
1079         /*
1080          * Query the EC to find out which _Qxx method we need to evaluate.
1081          * Note that successful completion of the query causes the ACPI_EC_SCI
1082          * bit to be cleared (and thus clearing the interrupt source).
1083          */
1084         result = acpi_ec_transaction(ec, &q->transaction);
1085         if (!value)
1086                 result = -ENODATA;
1087         if (result)
1088                 goto err_exit;
1089
1090         q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1091         if (!q->handler) {
1092                 result = -ENODATA;
1093                 goto err_exit;
1094         }
1095
1096         /*
1097          * It is reported that _Qxx are evaluated in a parallel way on
1098          * Windows:
1099          * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1100          *
1101          * Put this log entry before schedule_work() in order to make
1102          * it appearing before any other log entries occurred during the
1103          * work queue execution.
1104          */
1105         ec_dbg_evt("Query(0x%02x) scheduled", value);
1106         if (!queue_work(ec_query_wq, &q->work)) {
1107                 ec_dbg_evt("Query(0x%02x) overlapped", value);
1108                 result = -EBUSY;
1109         }
1110
1111 err_exit:
1112         if (result)
1113                 acpi_ec_delete_query(q);
1114         if (data)
1115                 *data = value;
1116         return result;
1117 }
1118
1119 static void acpi_ec_check_event(struct acpi_ec *ec)
1120 {
1121         unsigned long flags;
1122
1123         if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1124                 if (ec_guard(ec)) {
1125                         spin_lock_irqsave(&ec->lock, flags);
1126                         /*
1127                          * Take care of the SCI_EVT unless no one else is
1128                          * taking care of it.
1129                          */
1130                         if (!ec->curr)
1131                                 advance_transaction(ec);
1132                         spin_unlock_irqrestore(&ec->lock, flags);
1133                 }
1134         }
1135 }
1136
1137 static void acpi_ec_event_handler(struct work_struct *work)
1138 {
1139         unsigned long flags;
1140         struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1141
1142         ec_dbg_evt("Event started");
1143
1144         spin_lock_irqsave(&ec->lock, flags);
1145         while (ec->nr_pending_queries) {
1146                 spin_unlock_irqrestore(&ec->lock, flags);
1147                 (void)acpi_ec_query(ec, NULL);
1148                 spin_lock_irqsave(&ec->lock, flags);
1149                 ec->nr_pending_queries--;
1150                 /*
1151                  * Before exit, make sure that this work item can be
1152                  * scheduled again. There might be QR_EC failures, leaving
1153                  * EC_FLAGS_QUERY_PENDING uncleared and preventing this work
1154                  * item from being scheduled again.
1155                  */
1156                 if (!ec->nr_pending_queries) {
1157                         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
1158                             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY)
1159                                 acpi_ec_complete_query(ec);
1160                 }
1161         }
1162         spin_unlock_irqrestore(&ec->lock, flags);
1163
1164         ec_dbg_evt("Event stopped");
1165
1166         acpi_ec_check_event(ec);
1167 }
1168
1169 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1170         u32 gpe_number, void *data)
1171 {
1172         unsigned long flags;
1173         struct acpi_ec *ec = data;
1174
1175         spin_lock_irqsave(&ec->lock, flags);
1176         advance_transaction(ec);
1177         spin_unlock_irqrestore(&ec->lock, flags);
1178         return ACPI_INTERRUPT_HANDLED;
1179 }
1180
1181 /* --------------------------------------------------------------------------
1182  *                           Address Space Management
1183  * -------------------------------------------------------------------------- */
1184
1185 static acpi_status
1186 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1187                       u32 bits, u64 *value64,
1188                       void *handler_context, void *region_context)
1189 {
1190         struct acpi_ec *ec = handler_context;
1191         int result = 0, i, bytes = bits / 8;
1192         u8 *value = (u8 *)value64;
1193
1194         if ((address > 0xFF) || !value || !handler_context)
1195                 return AE_BAD_PARAMETER;
1196
1197         if (function != ACPI_READ && function != ACPI_WRITE)
1198                 return AE_BAD_PARAMETER;
1199
1200         if (ec_busy_polling || bits > 8)
1201                 acpi_ec_burst_enable(ec);
1202
1203         for (i = 0; i < bytes; ++i, ++address, ++value)
1204                 result = (function == ACPI_READ) ?
1205                         acpi_ec_read(ec, address, value) :
1206                         acpi_ec_write(ec, address, *value);
1207
1208         if (ec_busy_polling || bits > 8)
1209                 acpi_ec_burst_disable(ec);
1210
1211         switch (result) {
1212         case -EINVAL:
1213                 return AE_BAD_PARAMETER;
1214         case -ENODEV:
1215                 return AE_NOT_FOUND;
1216         case -ETIME:
1217                 return AE_TIME;
1218         default:
1219                 return AE_OK;
1220         }
1221 }
1222
1223 /* --------------------------------------------------------------------------
1224  *                             Driver Interface
1225  * -------------------------------------------------------------------------- */
1226
1227 static acpi_status
1228 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1229
1230 static struct acpi_ec *make_acpi_ec(void)
1231 {
1232         struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1233
1234         if (!ec)
1235                 return NULL;
1236         ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
1237         mutex_init(&ec->mutex);
1238         init_waitqueue_head(&ec->wait);
1239         INIT_LIST_HEAD(&ec->list);
1240         spin_lock_init(&ec->lock);
1241         INIT_WORK(&ec->work, acpi_ec_event_handler);
1242         ec->timestamp = jiffies;
1243         return ec;
1244 }
1245
1246 static acpi_status
1247 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1248                                void *context, void **return_value)
1249 {
1250         char node_name[5];
1251         struct acpi_buffer buffer = { sizeof(node_name), node_name };
1252         struct acpi_ec *ec = context;
1253         int value = 0;
1254         acpi_status status;
1255
1256         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1257
1258         if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1259                 acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1260         return AE_OK;
1261 }
1262
1263 static acpi_status
1264 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1265 {
1266         acpi_status status;
1267         unsigned long long tmp = 0;
1268         struct acpi_ec *ec = context;
1269
1270         /* clear addr values, ec_parse_io_ports depend on it */
1271         ec->command_addr = ec->data_addr = 0;
1272
1273         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1274                                      ec_parse_io_ports, ec);
1275         if (ACPI_FAILURE(status))
1276                 return status;
1277
1278         /* Get GPE bit assignment (EC events). */
1279         /* TODO: Add support for _GPE returning a package */
1280         status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1281         if (ACPI_FAILURE(status))
1282                 return status;
1283         ec->gpe = tmp;
1284         /* Use the global lock for all EC transactions? */
1285         tmp = 0;
1286         acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1287         ec->global_lock = tmp;
1288         ec->handle = handle;
1289         return AE_CTRL_TERMINATE;
1290 }
1291
1292 static int ec_install_handlers(struct acpi_ec *ec)
1293 {
1294         acpi_status status;
1295
1296         if (test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
1297                 return 0;
1298         status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1299                                   ACPI_GPE_EDGE_TRIGGERED,
1300                                   &acpi_ec_gpe_handler, ec);
1301         if (ACPI_FAILURE(status))
1302                 return -ENODEV;
1303
1304         acpi_ec_start(ec, false);
1305         status = acpi_install_address_space_handler(ec->handle,
1306                                                     ACPI_ADR_SPACE_EC,
1307                                                     &acpi_ec_space_handler,
1308                                                     NULL, ec);
1309         if (ACPI_FAILURE(status)) {
1310                 if (status == AE_NOT_FOUND) {
1311                         /*
1312                          * Maybe OS fails in evaluating the _REG object.
1313                          * The AE_NOT_FOUND error will be ignored and OS
1314                          * continue to initialize EC.
1315                          */
1316                         pr_err("Fail in evaluating the _REG object"
1317                                 " of EC device. Broken bios is suspected.\n");
1318                 } else {
1319                         acpi_ec_stop(ec, false);
1320                         acpi_remove_gpe_handler(NULL, ec->gpe,
1321                                 &acpi_ec_gpe_handler);
1322                         return -ENODEV;
1323                 }
1324         }
1325
1326         set_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
1327         return 0;
1328 }
1329
1330 static void ec_remove_handlers(struct acpi_ec *ec)
1331 {
1332         if (!test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
1333                 return;
1334         acpi_ec_stop(ec, false);
1335         if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1336                                 ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1337                 pr_err("failed to remove space handler\n");
1338         if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1339                                 &acpi_ec_gpe_handler)))
1340                 pr_err("failed to remove gpe handler\n");
1341         clear_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
1342 }
1343
1344 static int acpi_ec_add(struct acpi_device *device)
1345 {
1346         struct acpi_ec *ec = NULL;
1347         int ret;
1348
1349         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1350         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1351
1352         /* Check for boot EC */
1353         if (boot_ec &&
1354             (boot_ec->handle == device->handle ||
1355              boot_ec->handle == ACPI_ROOT_OBJECT)) {
1356                 ec = boot_ec;
1357                 boot_ec = NULL;
1358         } else {
1359                 ec = make_acpi_ec();
1360                 if (!ec)
1361                         return -ENOMEM;
1362         }
1363         if (ec_parse_device(device->handle, 0, ec, NULL) !=
1364                 AE_CTRL_TERMINATE) {
1365                         kfree(ec);
1366                         return -EINVAL;
1367         }
1368
1369         /* Find and register all query methods */
1370         acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1371                             acpi_ec_register_query_methods, NULL, ec, NULL);
1372
1373         if (!first_ec)
1374                 first_ec = ec;
1375         device->driver_data = ec;
1376
1377         ret = !!request_region(ec->data_addr, 1, "EC data");
1378         WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1379         ret = !!request_region(ec->command_addr, 1, "EC cmd");
1380         WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1381
1382         pr_info("GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
1383                           ec->gpe, ec->command_addr, ec->data_addr);
1384
1385         ret = ec_install_handlers(ec);
1386
1387         /* Reprobe devices depending on the EC */
1388         acpi_walk_dep_device_list(ec->handle);
1389
1390         /* EC is fully operational, allow queries */
1391         clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
1392
1393         /* Clear stale _Q events if hardware might require that */
1394         if (EC_FLAGS_CLEAR_ON_RESUME)
1395                 acpi_ec_clear(ec);
1396         return ret;
1397 }
1398
1399 static int acpi_ec_remove(struct acpi_device *device)
1400 {
1401         struct acpi_ec *ec;
1402
1403         if (!device)
1404                 return -EINVAL;
1405
1406         ec = acpi_driver_data(device);
1407         ec_remove_handlers(ec);
1408         acpi_ec_remove_query_handlers(ec, true, 0);
1409         release_region(ec->data_addr, 1);
1410         release_region(ec->command_addr, 1);
1411         device->driver_data = NULL;
1412         if (ec == first_ec)
1413                 first_ec = NULL;
1414         kfree(ec);
1415         return 0;
1416 }
1417
1418 static acpi_status
1419 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1420 {
1421         struct acpi_ec *ec = context;
1422
1423         if (resource->type != ACPI_RESOURCE_TYPE_IO)
1424                 return AE_OK;
1425
1426         /*
1427          * The first address region returned is the data port, and
1428          * the second address region returned is the status/command
1429          * port.
1430          */
1431         if (ec->data_addr == 0)
1432                 ec->data_addr = resource->data.io.minimum;
1433         else if (ec->command_addr == 0)
1434                 ec->command_addr = resource->data.io.minimum;
1435         else
1436                 return AE_CTRL_TERMINATE;
1437
1438         return AE_OK;
1439 }
1440
1441 int __init acpi_boot_ec_enable(void)
1442 {
1443         if (!boot_ec || test_bit(EC_FLAGS_HANDLERS_INSTALLED, &boot_ec->flags))
1444                 return 0;
1445         if (!ec_install_handlers(boot_ec)) {
1446                 first_ec = boot_ec;
1447                 return 0;
1448         }
1449         return -EFAULT;
1450 }
1451
1452 static const struct acpi_device_id ec_device_ids[] = {
1453         {"PNP0C09", 0},
1454         {"", 0},
1455 };
1456
1457 /* Some BIOS do not survive early DSDT scan, skip it */
1458 static int ec_skip_dsdt_scan(const struct dmi_system_id *id)
1459 {
1460         EC_FLAGS_SKIP_DSDT_SCAN = 1;
1461         return 0;
1462 }
1463
1464 /* ASUStek often supplies us with broken ECDT, validate it */
1465 static int ec_validate_ecdt(const struct dmi_system_id *id)
1466 {
1467         EC_FLAGS_VALIDATE_ECDT = 1;
1468         return 0;
1469 }
1470
1471 #if 0
1472 /*
1473  * Some EC firmware variations refuses to respond QR_EC when SCI_EVT is not
1474  * set, for which case, we complete the QR_EC without issuing it to the
1475  * firmware.
1476  * https://bugzilla.kernel.org/show_bug.cgi?id=82611
1477  * https://bugzilla.kernel.org/show_bug.cgi?id=97381
1478  */
1479 static int ec_flag_query_handshake(const struct dmi_system_id *id)
1480 {
1481         pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
1482         EC_FLAGS_QUERY_HANDSHAKE = 1;
1483         return 0;
1484 }
1485 #endif
1486
1487 /*
1488  * On some hardware it is necessary to clear events accumulated by the EC during
1489  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1490  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1491  *
1492  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1493  *
1494  * Ideally, the EC should also be instructed NOT to accumulate events during
1495  * sleep (which Windows seems to do somehow), but the interface to control this
1496  * behaviour is not known at this time.
1497  *
1498  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1499  * however it is very likely that other Samsung models are affected.
1500  *
1501  * On systems which don't accumulate _Q events during sleep, this extra check
1502  * should be harmless.
1503  */
1504 static int ec_clear_on_resume(const struct dmi_system_id *id)
1505 {
1506         pr_debug("Detected system needing EC poll on resume.\n");
1507         EC_FLAGS_CLEAR_ON_RESUME = 1;
1508         ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1509         return 0;
1510 }
1511
1512 static struct dmi_system_id ec_dmi_table[] __initdata = {
1513         {
1514         ec_skip_dsdt_scan, "Compal JFL92", {
1515         DMI_MATCH(DMI_BIOS_VENDOR, "COMPAL"),
1516         DMI_MATCH(DMI_BOARD_NAME, "JFL92") }, NULL},
1517         {
1518         ec_validate_ecdt, "MSI MS-171F", {
1519         DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1520         DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
1521         {
1522         ec_validate_ecdt, "ASUS hardware", {
1523         DMI_MATCH(DMI_BIOS_VENDOR, "ASUS") }, NULL},
1524         {
1525         ec_validate_ecdt, "ASUS hardware", {
1526         DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer Inc.") }, NULL},
1527         {
1528         ec_skip_dsdt_scan, "HP Folio 13", {
1529         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
1530         DMI_MATCH(DMI_PRODUCT_NAME, "HP Folio 13"),}, NULL},
1531         {
1532         ec_validate_ecdt, "ASUS hardware", {
1533         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTek Computer Inc."),
1534         DMI_MATCH(DMI_PRODUCT_NAME, "L4R"),}, NULL},
1535         {
1536         ec_clear_on_resume, "Samsung hardware", {
1537         DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1538         {},
1539 };
1540
1541 int __init acpi_ec_ecdt_probe(void)
1542 {
1543         acpi_status status;
1544         struct acpi_ec *saved_ec = NULL;
1545         struct acpi_table_ecdt *ecdt_ptr;
1546
1547         boot_ec = make_acpi_ec();
1548         if (!boot_ec)
1549                 return -ENOMEM;
1550         /*
1551          * Generate a boot ec context
1552          */
1553         dmi_check_system(ec_dmi_table);
1554         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1555                                 (struct acpi_table_header **)&ecdt_ptr);
1556         if (ACPI_SUCCESS(status)) {
1557                 pr_info("EC description table is found, configuring boot EC\n");
1558                 boot_ec->command_addr = ecdt_ptr->control.address;
1559                 boot_ec->data_addr = ecdt_ptr->data.address;
1560                 boot_ec->gpe = ecdt_ptr->gpe;
1561                 boot_ec->handle = ACPI_ROOT_OBJECT;
1562                 acpi_get_handle(ACPI_ROOT_OBJECT, ecdt_ptr->id,
1563                                 &boot_ec->handle);
1564                 /* Don't trust ECDT, which comes from ASUSTek */
1565                 if (!EC_FLAGS_VALIDATE_ECDT)
1566                         goto install;
1567                 saved_ec = kmemdup(boot_ec, sizeof(struct acpi_ec), GFP_KERNEL);
1568                 if (!saved_ec)
1569                         return -ENOMEM;
1570         /* fall through */
1571         }
1572
1573         if (EC_FLAGS_SKIP_DSDT_SCAN) {
1574                 kfree(saved_ec);
1575                 return -ENODEV;
1576         }
1577
1578         /* This workaround is needed only on some broken machines,
1579          * which require early EC, but fail to provide ECDT */
1580         pr_debug("Look up EC in DSDT\n");
1581         status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device,
1582                                         boot_ec, NULL);
1583         /* Check that acpi_get_devices actually find something */
1584         if (ACPI_FAILURE(status) || !boot_ec->handle)
1585                 goto error;
1586         if (saved_ec) {
1587                 /* try to find good ECDT from ASUSTek */
1588                 if (saved_ec->command_addr != boot_ec->command_addr ||
1589                     saved_ec->data_addr != boot_ec->data_addr ||
1590                     saved_ec->gpe != boot_ec->gpe ||
1591                     saved_ec->handle != boot_ec->handle)
1592                         pr_info("ASUSTek keeps feeding us with broken "
1593                         "ECDT tables, which are very hard to workaround. "
1594                         "Trying to use DSDT EC info instead. Please send "
1595                         "output of acpidump to linux-acpi@vger.kernel.org\n");
1596                 kfree(saved_ec);
1597                 saved_ec = NULL;
1598         } else {
1599                 /* We really need to limit this workaround, the only ASUS,
1600                 * which needs it, has fake EC._INI method, so use it as flag.
1601                 * Keep boot_ec struct as it will be needed soon.
1602                 */
1603                 if (!dmi_name_in_vendors("ASUS") ||
1604                     !acpi_has_method(boot_ec->handle, "_INI"))
1605                         return -ENODEV;
1606         }
1607 install:
1608         if (!ec_install_handlers(boot_ec)) {
1609                 first_ec = boot_ec;
1610                 return 0;
1611         }
1612 error:
1613         kfree(boot_ec);
1614         kfree(saved_ec);
1615         boot_ec = NULL;
1616         return -ENODEV;
1617 }
1618
1619 static int param_set_event_clearing(const char *val, struct kernel_param *kp)
1620 {
1621         int result = 0;
1622
1623         if (!strncmp(val, "status", sizeof("status") - 1)) {
1624                 ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1625                 pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
1626         } else if (!strncmp(val, "query", sizeof("query") - 1)) {
1627                 ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
1628                 pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
1629         } else if (!strncmp(val, "event", sizeof("event") - 1)) {
1630                 ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
1631                 pr_info("Assuming SCI_EVT clearing on event reads\n");
1632         } else
1633                 result = -EINVAL;
1634         return result;
1635 }
1636
1637 static int param_get_event_clearing(char *buffer, struct kernel_param *kp)
1638 {
1639         switch (ec_event_clearing) {
1640         case ACPI_EC_EVT_TIMING_STATUS:
1641                 return sprintf(buffer, "status");
1642         case ACPI_EC_EVT_TIMING_QUERY:
1643                 return sprintf(buffer, "query");
1644         case ACPI_EC_EVT_TIMING_EVENT:
1645                 return sprintf(buffer, "event");
1646         default:
1647                 return sprintf(buffer, "invalid");
1648         }
1649         return 0;
1650 }
1651
1652 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
1653                   NULL, 0644);
1654 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
1655
1656 static struct acpi_driver acpi_ec_driver = {
1657         .name = "ec",
1658         .class = ACPI_EC_CLASS,
1659         .ids = ec_device_ids,
1660         .ops = {
1661                 .add = acpi_ec_add,
1662                 .remove = acpi_ec_remove,
1663                 },
1664 };
1665
1666 static inline int acpi_ec_query_init(void)
1667 {
1668         if (!ec_query_wq) {
1669                 ec_query_wq = alloc_workqueue("kec_query", 0,
1670                                               ec_max_queries);
1671                 if (!ec_query_wq)
1672                         return -ENODEV;
1673         }
1674         return 0;
1675 }
1676
1677 static inline void acpi_ec_query_exit(void)
1678 {
1679         if (ec_query_wq) {
1680                 destroy_workqueue(ec_query_wq);
1681                 ec_query_wq = NULL;
1682         }
1683 }
1684
1685 int __init acpi_ec_init(void)
1686 {
1687         int result;
1688
1689         /* register workqueue for _Qxx evaluations */
1690         result = acpi_ec_query_init();
1691         if (result)
1692                 goto err_exit;
1693         /* Now register the driver for the EC */
1694         result = acpi_bus_register_driver(&acpi_ec_driver);
1695         if (result)
1696                 goto err_exit;
1697
1698 err_exit:
1699         if (result)
1700                 acpi_ec_query_exit();
1701         return result;
1702 }
1703
1704 /* EC driver currently not unloadable */
1705 #if 0
1706 static void __exit acpi_ec_exit(void)
1707 {
1708
1709         acpi_bus_unregister_driver(&acpi_ec_driver);
1710         acpi_ec_query_exit();
1711 }
1712 #endif  /* 0 */