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
 105 enum {
 106         EC_FLAGS_QUERY_PENDING,         /* Query is pending */
 107         EC_FLAGS_QUERY_GUARDING,        /* Guard for SCI_EVT check */
 108         EC_FLAGS_GPE_HANDLER_INSTALLED, /* GPE handler installed */
 109         EC_FLAGS_EC_HANDLER_INSTALLED,  /* OpReg handler 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_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
 179 static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
 180 static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
 181
 182 /* --------------------------------------------------------------------------
 183  *                           Logging/Debugging
 184  * -------------------------------------------------------------------------- */
 185
 186 /*
 187  * Splitters used by the developers to track the boundary of the EC
 188  * handling processes.
 189  */
 190 #ifdef DEBUG
 191 #define EC_DBG_SEP      " "
 192 #define EC_DBG_DRV      "+++++"
 193 #define EC_DBG_STM      "====="
 194 #define EC_DBG_REQ      "*****"
 195 #define EC_DBG_EVT      "#####"
 196 #else
 197 #define EC_DBG_SEP      ""
 198 #define EC_DBG_DRV
 199 #define EC_DBG_STM
 200 #define EC_DBG_REQ
 201 #define EC_DBG_EVT
 202 #endif
 203
 204 #define ec_log_raw(fmt, ...) \
 205         pr_info(fmt "\n", ##__VA_ARGS__)
 206 #define ec_dbg_raw(fmt, ...) \
 207         pr_debug(fmt "\n", ##__VA_ARGS__)
 208 #define ec_log(filter, fmt, ...) \
 209         ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
 210 #define ec_dbg(filter, fmt, ...) \
 211         ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
 212
 213 #define ec_log_drv(fmt, ...) \
 214         ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
 215 #define ec_dbg_drv(fmt, ...) \
 216         ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
 217 #define ec_dbg_stm(fmt, ...) \
 218         ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
 219 #define ec_dbg_req(fmt, ...) \
 220         ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
 221 #define ec_dbg_evt(fmt, ...) \
 222         ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
 223 #define ec_dbg_ref(ec, fmt, ...) \
 224         ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
 225
 226 /* --------------------------------------------------------------------------
 227  *                           Device Flags
 228  * -------------------------------------------------------------------------- */
 229
 230 static bool acpi_ec_started(struct acpi_ec *ec)
 231 {
 232         return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
 233                !test_bit(EC_FLAGS_STOPPED, &ec->flags);
 234 }
 235
 236 static bool acpi_ec_flushed(struct acpi_ec *ec)
 237 {
 238         return ec->reference_count == 1;
 239 }
 240
 241 /* --------------------------------------------------------------------------
 242  *                           EC Registers
 243  * -------------------------------------------------------------------------- */
 244
 245 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
 246 {
 247         u8 x = inb(ec->command_addr);
 248
 249         ec_dbg_raw("EC_SC(R) = 0x%2.2x "
 250                    "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
 251                    x,
 252                    !!(x & ACPI_EC_FLAG_SCI),
 253                    !!(x & ACPI_EC_FLAG_BURST),
 254                    !!(x & ACPI_EC_FLAG_CMD),
 255                    !!(x & ACPI_EC_FLAG_IBF),
 256                    !!(x & ACPI_EC_FLAG_OBF));
 257         return x;
 258 }
 259
 260 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
 261 {
 262         u8 x = inb(ec->data_addr);
 263
 264         ec->timestamp = jiffies;
 265         ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
 266         return x;
 267 }
 268
 269 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
 270 {
 271         ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
 272         outb(command, ec->command_addr);
 273         ec->timestamp = jiffies;
 274 }
 275
 276 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
 277 {
 278         ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
 279         outb(data, ec->data_addr);
 280         ec->timestamp = jiffies;
 281 }
 282
 283 #ifdef DEBUG
 284 static const char *acpi_ec_cmd_string(u8 cmd)
 285 {
 286         switch (cmd) {
 287         case 0x80:
 288                 return "RD_EC";
 289         case 0x81:
 290                 return "WR_EC";
 291         case 0x82:
 292                 return "BE_EC";
 293         case 0x83:
 294                 return "BD_EC";
 295         case 0x84:
 296                 return "QR_EC";
 297         }
 298         return "UNKNOWN";
 299 }
 300 #else
 301 #define acpi_ec_cmd_string(cmd)         "UNDEF"
 302 #endif
 303
 304 /* --------------------------------------------------------------------------
 305  *                           GPE Registers
 306  * -------------------------------------------------------------------------- */
 307
 308 static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec)
 309 {
 310         acpi_event_status gpe_status = 0;
 311
 312         (void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
 313         return (gpe_status & ACPI_EVENT_FLAG_STATUS_SET) ? true : false;
 314 }
 315
 316 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
 317 {
 318         if (open)
 319                 acpi_enable_gpe(NULL, ec->gpe);
 320         else {
 321                 BUG_ON(ec->reference_count < 1);
 322                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
 323         }
 324         if (acpi_ec_is_gpe_raised(ec)) {
 325                 /*
 326                  * On some platforms, EN=1 writes cannot trigger GPE. So
 327                  * software need to manually trigger a pseudo GPE event on
 328                  * EN=1 writes.
 329                  */
 330                 ec_dbg_raw("Polling quirk");
 331                 advance_transaction(ec);
 332         }
 333 }
 334
 335 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
 336 {
 337         if (close)
 338                 acpi_disable_gpe(NULL, ec->gpe);
 339         else {
 340                 BUG_ON(ec->reference_count < 1);
 341                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
 342         }
 343 }
 344
 345 static inline void acpi_ec_clear_gpe(struct acpi_ec *ec)
 346 {
 347         /*
 348          * GPE STS is a W1C register, which means:
 349          * 1. Software can clear it without worrying about clearing other
 350          *    GPEs' STS bits when the hardware sets them in parallel.
 351          * 2. As long as software can ensure only clearing it when it is
 352          *    set, hardware won't set it in parallel.
 353          * So software can clear GPE in any contexts.
 354          * Warning: do not move the check into advance_transaction() as the
 355          * EC commands will be sent without GPE raised.
 356          */
 357         if (!acpi_ec_is_gpe_raised(ec))
 358                 return;
 359         acpi_clear_gpe(NULL, ec->gpe);
 360 }
 361
 362 /* --------------------------------------------------------------------------
 363  *                           Transaction Management
 364  * -------------------------------------------------------------------------- */
 365
 366 static void acpi_ec_submit_request(struct acpi_ec *ec)
 367 {
 368         ec->reference_count++;
 369         if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags) &&
 370             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 (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags) &&
 380             ec->reference_count == 0)
 381                 acpi_ec_disable_gpe(ec, true);
 382         flushed = acpi_ec_flushed(ec);
 383         if (flushed)
 384                 wake_up(&ec->wait);
 385 }
 386
 387 static void acpi_ec_set_storm(struct acpi_ec *ec, u8 flag)
 388 {
 389         if (!test_bit(flag, &ec->flags)) {
 390                 acpi_ec_disable_gpe(ec, false);
 391                 ec_dbg_drv("Polling enabled");
 392                 set_bit(flag, &ec->flags);
 393         }
 394 }
 395
 396 static void acpi_ec_clear_storm(struct acpi_ec *ec, u8 flag)
 397 {
 398         if (test_bit(flag, &ec->flags)) {
 399                 clear_bit(flag, &ec->flags);
 400                 acpi_ec_enable_gpe(ec, false);
 401                 ec_dbg_drv("Polling disabled");
 402         }
 403 }
 404
 405 /*
 406  * acpi_ec_submit_flushable_request() - Increase the reference count unless
 407  *                                      the flush operation is not in
 408  *                                      progress
 409  * @ec: the EC device
 410  *
 411  * This function must be used before taking a new action that should hold
 412  * the reference count.  If this function returns false, then the action
 413  * must be discarded or it will prevent the flush operation from being
 414  * completed.
 415  */
 416 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
 417 {
 418         if (!acpi_ec_started(ec))
 419                 return false;
 420         acpi_ec_submit_request(ec);
 421         return true;
 422 }
 423
 424 static void acpi_ec_submit_query(struct acpi_ec *ec)
 425 {
 426         if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
 427                 ec_dbg_evt("Command(%s) submitted/blocked",
 428                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 429                 ec->nr_pending_queries++;
 430                 schedule_work(&ec->work);
 431         }
 432 }
 433
 434 static void acpi_ec_complete_query(struct acpi_ec *ec)
 435 {
 436         if (test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
 437                 clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
 438                 ec_dbg_evt("Command(%s) unblocked",
 439                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 440         }
 441 }
 442
 443 static bool acpi_ec_guard_event(struct acpi_ec *ec)
 444 {
 445         bool guarded = true;
 446         unsigned long flags;
 447
 448         spin_lock_irqsave(&ec->lock, flags);
 449         /*
 450          * If firmware SCI_EVT clearing timing is "event", we actually
 451          * don't know when the SCI_EVT will be cleared by firmware after
 452          * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
 453          * acceptable period.
 454          *
 455          * The guarding period begins when EC_FLAGS_QUERY_PENDING is
 456          * flagged, which means SCI_EVT check has just been performed.
 457          * But if the current transaction is ACPI_EC_COMMAND_QUERY, the
 458          * guarding should have already been performed (via
 459          * EC_FLAGS_QUERY_GUARDING) and should not be applied so that the
 460          * ACPI_EC_COMMAND_QUERY transaction can be transitioned into
 461          * ACPI_EC_COMMAND_POLL state immediately.
 462          */
 463         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
 464             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY ||
 465             !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) ||
 466             (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY))
 467                 guarded = false;
 468         spin_unlock_irqrestore(&ec->lock, flags);
 469         return guarded;
 470 }
 471
 472 static int ec_transaction_polled(struct acpi_ec *ec)
 473 {
 474         unsigned long flags;
 475         int ret = 0;
 476
 477         spin_lock_irqsave(&ec->lock, flags);
 478         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
 479                 ret = 1;
 480         spin_unlock_irqrestore(&ec->lock, flags);
 481         return ret;
 482 }
 483
 484 static int ec_transaction_completed(struct acpi_ec *ec)
 485 {
 486         unsigned long flags;
 487         int ret = 0;
 488
 489         spin_lock_irqsave(&ec->lock, flags);
 490         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
 491                 ret = 1;
 492         spin_unlock_irqrestore(&ec->lock, flags);
 493         return ret;
 494 }
 495
 496 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
 497 {
 498         ec->curr->flags |= flag;
 499         if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
 500                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS &&
 501                     flag == ACPI_EC_COMMAND_POLL)
 502                         acpi_ec_complete_query(ec);
 503                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY &&
 504                     flag == ACPI_EC_COMMAND_COMPLETE)
 505                         acpi_ec_complete_query(ec);
 506                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 507                     flag == ACPI_EC_COMMAND_COMPLETE)
 508                         set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
 509         }
 510 }
 511
 512 static void advance_transaction(struct acpi_ec *ec)
 513 {
 514         struct transaction *t;
 515         u8 status;
 516         bool wakeup = false;
 517
 518         ec_dbg_stm("%s (%d)", in_interrupt() ? "IRQ" : "TASK",
 519                    smp_processor_id());
 520         /*
 521          * By always clearing STS before handling all indications, we can
 522          * ensure a hardware STS 0->1 change after this clearing can always
 523          * trigger a GPE interrupt.
 524          */
 525         acpi_ec_clear_gpe(ec);
 526         status = acpi_ec_read_status(ec);
 527         t = ec->curr;
 528         /*
 529          * Another IRQ or a guarded polling mode advancement is detected,
 530          * the next QR_EC submission is then allowed.
 531          */
 532         if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
 533                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 534                     (!ec->nr_pending_queries ||
 535                      test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) {
 536                         clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
 537                         acpi_ec_complete_query(ec);
 538                 }
 539         }
 540         if (!t)
 541                 goto err;
 542         if (t->flags & ACPI_EC_COMMAND_POLL) {
 543                 if (t->wlen > t->wi) {
 544                         if ((status & ACPI_EC_FLAG_IBF) == 0)
 545                                 acpi_ec_write_data(ec, t->wdata[t->wi++]);
 546                         else
 547                                 goto err;
 548                 } else if (t->rlen > t->ri) {
 549                         if ((status & ACPI_EC_FLAG_OBF) == 1) {
 550                                 t->rdata[t->ri++] = acpi_ec_read_data(ec);
 551                                 if (t->rlen == t->ri) {
 552                                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 553                                         if (t->command == ACPI_EC_COMMAND_QUERY)
 554                                                 ec_dbg_evt("Command(%s) completed by hardware",
 555                                                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 556                                         wakeup = true;
 557                                 }
 558                         } else
 559                                 goto err;
 560                 } else if (t->wlen == t->wi &&
 561                            (status & ACPI_EC_FLAG_IBF) == 0) {
 562                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 563                         wakeup = true;
 564                 }
 565                 goto out;
 566         } else {
 567                 if (EC_FLAGS_QUERY_HANDSHAKE &&
 568                     !(status & ACPI_EC_FLAG_SCI) &&
 569                     (t->command == ACPI_EC_COMMAND_QUERY)) {
 570                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
 571                         t->rdata[t->ri++] = 0x00;
 572                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 573                         ec_dbg_evt("Command(%s) completed by software",
 574                                    acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 575                         wakeup = true;
 576                 } else if ((status & ACPI_EC_FLAG_IBF) == 0) {
 577                         acpi_ec_write_cmd(ec, t->command);
 578                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
 579                 } else
 580                         goto err;
 581                 goto out;
 582         }
 583 err:
 584         /*
 585          * If SCI bit is set, then don't think it's a false IRQ
 586          * otherwise will take a not handled IRQ as a false one.
 587          */
 588         if (!(status & ACPI_EC_FLAG_SCI)) {
 589                 if (in_interrupt() && t) {
 590                         if (t->irq_count < ec_storm_threshold)
 591                                 ++t->irq_count;
 592                         /* Allow triggering on 0 threshold */
 593                         if (t->irq_count == ec_storm_threshold)
 594                                 acpi_ec_set_storm(ec, EC_FLAGS_COMMAND_STORM);
 595                 }
 596         }
 597 out:
 598         if (status & ACPI_EC_FLAG_SCI)
 599                 acpi_ec_submit_query(ec);
 600         if (wakeup && in_interrupt())
 601                 wake_up(&ec->wait);
 602 }
 603
 604 static void start_transaction(struct acpi_ec *ec)
 605 {
 606         ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
 607         ec->curr->flags = 0;
 608 }
 609
 610 static int ec_guard(struct acpi_ec *ec)
 611 {
 612         unsigned long guard = usecs_to_jiffies(ec_polling_guard);
 613         unsigned long timeout = ec->timestamp + guard;
 614
 615         /* Ensure guarding period before polling EC status */
 616         do {
 617                 if (ec_busy_polling) {
 618                         /* Perform busy polling */
 619                         if (ec_transaction_completed(ec))
 620                                 return 0;
 621                         udelay(jiffies_to_usecs(guard));
 622                 } else {
 623                         /*
 624                          * Perform wait polling
 625                          * 1. Wait the transaction to be completed by the
 626                          *    GPE handler after the transaction enters
 627                          *    ACPI_EC_COMMAND_POLL state.
 628                          * 2. A special guarding logic is also required
 629                          *    for event clearing mode "event" before the
 630                          *    transaction enters ACPI_EC_COMMAND_POLL
 631                          *    state.
 632                          */
 633                         if (!ec_transaction_polled(ec) &&
 634                             !acpi_ec_guard_event(ec))
 635                                 break;
 636                         if (wait_event_timeout(ec->wait,
 637                                                ec_transaction_completed(ec),
 638                                                guard))
 639                                 return 0;
 640                 }
 641         } while (time_before(jiffies, timeout));
 642         return -ETIME;
 643 }
 644
 645 static int ec_poll(struct acpi_ec *ec)
 646 {
 647         unsigned long flags;
 648         int repeat = 5; /* number of command restarts */
 649
 650         while (repeat--) {
 651                 unsigned long delay = jiffies +
 652                         msecs_to_jiffies(ec_delay);
 653                 do {
 654                         if (!ec_guard(ec))
 655                                 return 0;
 656                         spin_lock_irqsave(&ec->lock, flags);
 657                         advance_transaction(ec);
 658                         spin_unlock_irqrestore(&ec->lock, flags);
 659                 } while (time_before(jiffies, delay));
 660                 pr_debug("controller reset, restart transaction\n");
 661                 spin_lock_irqsave(&ec->lock, flags);
 662                 start_transaction(ec);
 663                 spin_unlock_irqrestore(&ec->lock, flags);
 664         }
 665         return -ETIME;
 666 }
 667
 668 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
 669                                         struct transaction *t)
 670 {
 671         unsigned long tmp;
 672         int ret = 0;
 673
 674         /* start transaction */
 675         spin_lock_irqsave(&ec->lock, tmp);
 676         /* Enable GPE for command processing (IBF=0/OBF=1) */
 677         if (!acpi_ec_submit_flushable_request(ec)) {
 678                 ret = -EINVAL;
 679                 goto unlock;
 680         }
 681         ec_dbg_ref(ec, "Increase command");
 682         /* following two actions should be kept atomic */
 683         ec->curr = t;
 684         ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
 685         start_transaction(ec);
 686         spin_unlock_irqrestore(&ec->lock, tmp);
 687
 688         ret = ec_poll(ec);
 689
 690         spin_lock_irqsave(&ec->lock, tmp);
 691         if (t->irq_count == ec_storm_threshold)
 692                 acpi_ec_clear_storm(ec, EC_FLAGS_COMMAND_STORM);
 693         ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
 694         ec->curr = NULL;
 695         /* Disable GPE for command processing (IBF=0/OBF=1) */
 696         acpi_ec_complete_request(ec);
 697         ec_dbg_ref(ec, "Decrease command");
 698 unlock:
 699         spin_unlock_irqrestore(&ec->lock, tmp);
 700         return ret;
 701 }
 702
 703 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
 704 {
 705         int status;
 706         u32 glk;
 707
 708         if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
 709                 return -EINVAL;
 710         if (t->rdata)
 711                 memset(t->rdata, 0, t->rlen);
 712
 713         mutex_lock(&ec->mutex);
 714         if (ec->global_lock) {
 715                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
 716                 if (ACPI_FAILURE(status)) {
 717                         status = -ENODEV;
 718                         goto unlock;
 719                 }
 720         }
 721
 722         status = acpi_ec_transaction_unlocked(ec, t);
 723
 724         if (ec->global_lock)
 725                 acpi_release_global_lock(glk);
 726 unlock:
 727         mutex_unlock(&ec->mutex);
 728         return status;
 729 }
 730
 731 static int acpi_ec_burst_enable(struct acpi_ec *ec)
 732 {
 733         u8 d;
 734         struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
 735                                 .wdata = NULL, .rdata = &d,
 736                                 .wlen = 0, .rlen = 1};
 737
 738         return acpi_ec_transaction(ec, &t);
 739 }
 740
 741 static int acpi_ec_burst_disable(struct acpi_ec *ec)
 742 {
 743         struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
 744                                 .wdata = NULL, .rdata = NULL,
 745                                 .wlen = 0, .rlen = 0};
 746
 747         return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
 748                                 acpi_ec_transaction(ec, &t) : 0;
 749 }
 750
 751 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
 752 {
 753         int result;
 754         u8 d;
 755         struct transaction t = {.command = ACPI_EC_COMMAND_READ,
 756                                 .wdata = &address, .rdata = &d,
 757                                 .wlen = 1, .rlen = 1};
 758
 759         result = acpi_ec_transaction(ec, &t);
 760         *data = d;
 761         return result;
 762 }
 763
 764 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
 765 {
 766         u8 wdata[2] = { address, data };
 767         struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
 768                                 .wdata = wdata, .rdata = NULL,
 769                                 .wlen = 2, .rlen = 0};
 770
 771         return acpi_ec_transaction(ec, &t);
 772 }
 773
 774 int ec_read(u8 addr, u8 *val)
 775 {
 776         int err;
 777         u8 temp_data;
 778
 779         if (!first_ec)
 780                 return -ENODEV;
 781
 782         err = acpi_ec_read(first_ec, addr, &temp_data);
 783
 784         if (!err) {
 785                 *val = temp_data;
 786                 return 0;
 787         }
 788         return err;
 789 }
 790 EXPORT_SYMBOL(ec_read);
 791
 792 int ec_write(u8 addr, u8 val)
 793 {
 794         int err;
 795
 796         if (!first_ec)
 797                 return -ENODEV;
 798
 799         err = acpi_ec_write(first_ec, addr, val);
 800
 801         return err;
 802 }
 803 EXPORT_SYMBOL(ec_write);
 804
 805 int ec_transaction(u8 command,
 806                    const u8 *wdata, unsigned wdata_len,
 807                    u8 *rdata, unsigned rdata_len)
 808 {
 809         struct transaction t = {.command = command,
 810                                 .wdata = wdata, .rdata = rdata,
 811                                 .wlen = wdata_len, .rlen = rdata_len};
 812
 813         if (!first_ec)
 814                 return -ENODEV;
 815
 816         return acpi_ec_transaction(first_ec, &t);
 817 }
 818 EXPORT_SYMBOL(ec_transaction);
 819
 820 /* Get the handle to the EC device */
 821 acpi_handle ec_get_handle(void)
 822 {
 823         if (!first_ec)
 824                 return NULL;
 825         return first_ec->handle;
 826 }
 827 EXPORT_SYMBOL(ec_get_handle);
 828
 829 /*
 830  * Process _Q events that might have accumulated in the EC.
 831  * Run with locked ec mutex.
 832  */
 833 static void acpi_ec_clear(struct acpi_ec *ec)
 834 {
 835         int i, status;
 836         u8 value = 0;
 837
 838         for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
 839                 status = acpi_ec_query(ec, &value);
 840                 if (status || !value)
 841                         break;
 842         }
 843
 844         if (unlikely(i == ACPI_EC_CLEAR_MAX))
 845                 pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
 846         else
 847                 pr_info("%d stale EC events cleared\n", i);
 848 }
 849
 850 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
 851 {
 852         unsigned long flags;
 853
 854         spin_lock_irqsave(&ec->lock, flags);
 855         if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
 856                 ec_dbg_drv("Starting EC");
 857                 /* Enable GPE for event processing (SCI_EVT=1) */
 858                 if (!resuming) {
 859                         acpi_ec_submit_request(ec);
 860                         ec_dbg_ref(ec, "Increase driver");
 861                 }
 862                 ec_log_drv("EC started");
 863         }
 864         spin_unlock_irqrestore(&ec->lock, flags);
 865 }
 866
 867 static bool acpi_ec_stopped(struct acpi_ec *ec)
 868 {
 869         unsigned long flags;
 870         bool flushed;
 871
 872         spin_lock_irqsave(&ec->lock, flags);
 873         flushed = acpi_ec_flushed(ec);
 874         spin_unlock_irqrestore(&ec->lock, flags);
 875         return flushed;
 876 }
 877
 878 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
 879 {
 880         unsigned long flags;
 881
 882         spin_lock_irqsave(&ec->lock, flags);
 883         if (acpi_ec_started(ec)) {
 884                 ec_dbg_drv("Stopping EC");
 885                 set_bit(EC_FLAGS_STOPPED, &ec->flags);
 886                 spin_unlock_irqrestore(&ec->lock, flags);
 887                 wait_event(ec->wait, acpi_ec_stopped(ec));
 888                 spin_lock_irqsave(&ec->lock, flags);
 889                 /* Disable GPE for event processing (SCI_EVT=1) */
 890                 if (!suspending) {
 891                         acpi_ec_complete_request(ec);
 892                         ec_dbg_ref(ec, "Decrease driver");
 893                 }
 894                 clear_bit(EC_FLAGS_STARTED, &ec->flags);
 895                 clear_bit(EC_FLAGS_STOPPED, &ec->flags);
 896                 ec_log_drv("EC stopped");
 897         }
 898         spin_unlock_irqrestore(&ec->lock, flags);
 899 }
 900
 901 void acpi_ec_block_transactions(void)
 902 {
 903         struct acpi_ec *ec = first_ec;
 904
 905         if (!ec)
 906                 return;
 907
 908         mutex_lock(&ec->mutex);
 909         /* Prevent transactions from being carried out */
 910         acpi_ec_stop(ec, true);
 911         mutex_unlock(&ec->mutex);
 912 }
 913
 914 void acpi_ec_unblock_transactions(void)
 915 {
 916         struct acpi_ec *ec = first_ec;
 917
 918         if (!ec)
 919                 return;
 920
 921         /* Allow transactions to be carried out again */
 922         acpi_ec_start(ec, true);
 923
 924         if (EC_FLAGS_CLEAR_ON_RESUME)
 925                 acpi_ec_clear(ec);
 926 }
 927
 928 void acpi_ec_unblock_transactions_early(void)
 929 {
 930         /*
 931          * Allow transactions to happen again (this function is called from
 932          * atomic context during wakeup, so we don't need to acquire the mutex).
 933          */
 934         if (first_ec)
 935                 acpi_ec_start(first_ec, true);
 936 }
 937
 938 /* --------------------------------------------------------------------------
 939                                 Event Management
 940    -------------------------------------------------------------------------- */
 941 static struct acpi_ec_query_handler *
 942 acpi_ec_get_query_handler(struct acpi_ec_query_handler *handler)
 943 {
 944         if (handler)
 945                 kref_get(&handler->kref);
 946         return handler;
 947 }
 948
 949 static struct acpi_ec_query_handler *
 950 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
 951 {
 952         struct acpi_ec_query_handler *handler;
 953         bool found = false;
 954
 955         mutex_lock(&ec->mutex);
 956         list_for_each_entry(handler, &ec->list, node) {
 957                 if (value == handler->query_bit) {
 958                         found = true;
 959                         break;
 960                 }
 961         }
 962         mutex_unlock(&ec->mutex);
 963         return found ? acpi_ec_get_query_handler(handler) : NULL;
 964 }
 965
 966 static void acpi_ec_query_handler_release(struct kref *kref)
 967 {
 968         struct acpi_ec_query_handler *handler =
 969                 container_of(kref, struct acpi_ec_query_handler, kref);
 970
 971         kfree(handler);
 972 }
 973
 974 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
 975 {
 976         kref_put(&handler->kref, acpi_ec_query_handler_release);
 977 }
 978
 979 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
 980                               acpi_handle handle, acpi_ec_query_func func,
 981                               void *data)
 982 {
 983         struct acpi_ec_query_handler *handler =
 984             kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
 985
 986         if (!handler)
 987                 return -ENOMEM;
 988
 989         handler->query_bit = query_bit;
 990         handler->handle = handle;
 991         handler->func = func;
 992         handler->data = data;
 993         mutex_lock(&ec->mutex);
 994         kref_init(&handler->kref);
 995         list_add(&handler->node, &ec->list);
 996         mutex_unlock(&ec->mutex);
 997         return 0;
 998 }
 999 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1000
1001 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1002                                           bool remove_all, u8 query_bit)
1003 {
1004         struct acpi_ec_query_handler *handler, *tmp;
1005         LIST_HEAD(free_list);
1006
1007         mutex_lock(&ec->mutex);
1008         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1009                 if (remove_all || query_bit == handler->query_bit) {
1010                         list_del_init(&handler->node);
1011                         list_add(&handler->node, &free_list);
1012                 }
1013         }
1014         mutex_unlock(&ec->mutex);
1015         list_for_each_entry_safe(handler, tmp, &free_list, node)
1016                 acpi_ec_put_query_handler(handler);
1017 }
1018
1019 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1020 {
1021         acpi_ec_remove_query_handlers(ec, false, query_bit);
1022 }
1023 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1024
1025 static struct acpi_ec_query *acpi_ec_create_query(u8 *pval)
1026 {
1027         struct acpi_ec_query *q;
1028         struct transaction *t;
1029
1030         q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1031         if (!q)
1032                 return NULL;
1033         INIT_WORK(&q->work, acpi_ec_event_processor);
1034         t = &q->transaction;
1035         t->command = ACPI_EC_COMMAND_QUERY;
1036         t->rdata = pval;
1037         t->rlen = 1;
1038         return q;
1039 }
1040
1041 static void acpi_ec_delete_query(struct acpi_ec_query *q)
1042 {
1043         if (q) {
1044                 if (q->handler)
1045                         acpi_ec_put_query_handler(q->handler);
1046                 kfree(q);
1047         }
1048 }
1049
1050 static void acpi_ec_event_processor(struct work_struct *work)
1051 {
1052         struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1053         struct acpi_ec_query_handler *handler = q->handler;
1054
1055         ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1056         if (handler->func)
1057                 handler->func(handler->data);
1058         else if (handler->handle)
1059                 acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1060         ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1061         acpi_ec_delete_query(q);
1062 }
1063
1064 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
1065 {
1066         u8 value = 0;
1067         int result;
1068         struct acpi_ec_query *q;
1069
1070         q = acpi_ec_create_query(&value);
1071         if (!q)
1072                 return -ENOMEM;
1073
1074         /*
1075          * Query the EC to find out which _Qxx method we need to evaluate.
1076          * Note that successful completion of the query causes the ACPI_EC_SCI
1077          * bit to be cleared (and thus clearing the interrupt source).
1078          */
1079         result = acpi_ec_transaction(ec, &q->transaction);
1080         if (!value)
1081                 result = -ENODATA;
1082         if (result)
1083                 goto err_exit;
1084
1085         q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1086         if (!q->handler) {
1087                 result = -ENODATA;
1088                 goto err_exit;
1089         }
1090
1091         /*
1092          * It is reported that _Qxx are evaluated in a parallel way on
1093          * Windows:
1094          * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1095          *
1096          * Put this log entry before schedule_work() in order to make
1097          * it appearing before any other log entries occurred during the
1098          * work queue execution.
1099          */
1100         ec_dbg_evt("Query(0x%02x) scheduled", value);
1101         if (!schedule_work(&q->work)) {
1102                 ec_dbg_evt("Query(0x%02x) overlapped", value);
1103                 result = -EBUSY;
1104         }
1105
1106 err_exit:
1107         if (result)
1108                 acpi_ec_delete_query(q);
1109         if (data)
1110                 *data = value;
1111         return result;
1112 }
1113
1114 static void acpi_ec_check_event(struct acpi_ec *ec)
1115 {
1116         unsigned long flags;
1117
1118         if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1119                 if (ec_guard(ec)) {
1120                         spin_lock_irqsave(&ec->lock, flags);
1121                         /*
1122                          * Take care of the SCI_EVT unless no one else is
1123                          * taking care of it.
1124                          */
1125                         if (!ec->curr)
1126                                 advance_transaction(ec);
1127                         spin_unlock_irqrestore(&ec->lock, flags);
1128                 }
1129         }
1130 }
1131
1132 static void acpi_ec_event_handler(struct work_struct *work)
1133 {
1134         unsigned long flags;
1135         struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1136
1137         ec_dbg_evt("Event started");
1138
1139         spin_lock_irqsave(&ec->lock, flags);
1140         while (ec->nr_pending_queries) {
1141                 spin_unlock_irqrestore(&ec->lock, flags);
1142                 (void)acpi_ec_query(ec, NULL);
1143                 spin_lock_irqsave(&ec->lock, flags);
1144                 ec->nr_pending_queries--;
1145                 /*
1146                  * Before exit, make sure that this work item can be
1147                  * scheduled again. There might be QR_EC failures, leaving
1148                  * EC_FLAGS_QUERY_PENDING uncleared and preventing this work
1149                  * item from being scheduled again.
1150                  */
1151                 if (!ec->nr_pending_queries) {
1152                         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
1153                             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY)
1154                                 acpi_ec_complete_query(ec);
1155                 }
1156         }
1157         spin_unlock_irqrestore(&ec->lock, flags);
1158
1159         ec_dbg_evt("Event stopped");
1160
1161         acpi_ec_check_event(ec);
1162 }
1163
1164 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1165         u32 gpe_number, void *data)
1166 {
1167         unsigned long flags;
1168         struct acpi_ec *ec = data;
1169
1170         spin_lock_irqsave(&ec->lock, flags);
1171         advance_transaction(ec);
1172         spin_unlock_irqrestore(&ec->lock, flags);
1173         return ACPI_INTERRUPT_HANDLED;
1174 }
1175
1176 /* --------------------------------------------------------------------------
1177  *                           Address Space Management
1178  * -------------------------------------------------------------------------- */
1179
1180 static acpi_status
1181 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1182                       u32 bits, u64 *value64,
1183                       void *handler_context, void *region_context)
1184 {
1185         struct acpi_ec *ec = handler_context;
1186         int result = 0, i, bytes = bits / 8;
1187         u8 *value = (u8 *)value64;
1188
1189         if ((address > 0xFF) || !value || !handler_context)
1190                 return AE_BAD_PARAMETER;
1191
1192         if (function != ACPI_READ && function != ACPI_WRITE)
1193                 return AE_BAD_PARAMETER;
1194
1195         if (ec_busy_polling || bits > 8)
1196                 acpi_ec_burst_enable(ec);
1197
1198         for (i = 0; i < bytes; ++i, ++address, ++value)
1199                 result = (function == ACPI_READ) ?
1200                         acpi_ec_read(ec, address, value) :
1201                         acpi_ec_write(ec, address, *value);
1202
1203         if (ec_busy_polling || bits > 8)
1204                 acpi_ec_burst_disable(ec);
1205
1206         switch (result) {
1207         case -EINVAL:
1208                 return AE_BAD_PARAMETER;
1209         case -ENODEV:
1210                 return AE_NOT_FOUND;
1211         case -ETIME:
1212                 return AE_TIME;
1213         default:
1214                 return AE_OK;
1215         }
1216 }
1217
1218 /* --------------------------------------------------------------------------
1219  *                             Driver Interface
1220  * -------------------------------------------------------------------------- */
1221
1222 static acpi_status
1223 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1224
1225 static struct acpi_ec *make_acpi_ec(void)
1226 {
1227         struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1228
1229         if (!ec)
1230                 return NULL;
1231         ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
1232         mutex_init(&ec->mutex);
1233         init_waitqueue_head(&ec->wait);
1234         INIT_LIST_HEAD(&ec->list);
1235         spin_lock_init(&ec->lock);
1236         INIT_WORK(&ec->work, acpi_ec_event_handler);
1237         ec->timestamp = jiffies;
1238         return ec;
1239 }
1240
1241 static acpi_status
1242 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1243                                void *context, void **return_value)
1244 {
1245         char node_name[5];
1246         struct acpi_buffer buffer = { sizeof(node_name), node_name };
1247         struct acpi_ec *ec = context;
1248         int value = 0;
1249         acpi_status status;
1250
1251         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1252
1253         if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1254                 acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1255         return AE_OK;
1256 }
1257
1258 static acpi_status
1259 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1260 {
1261         acpi_status status;
1262         unsigned long long tmp = 0;
1263         struct acpi_ec *ec = context;
1264
1265         /* clear addr values, ec_parse_io_ports depend on it */
1266         ec->command_addr = ec->data_addr = 0;
1267
1268         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1269                                      ec_parse_io_ports, ec);
1270         if (ACPI_FAILURE(status))
1271                 return status;
1272
1273         /* Get GPE bit assignment (EC events). */
1274         /* TODO: Add support for _GPE returning a package */
1275         status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1276         if (ACPI_FAILURE(status))
1277                 return status;
1278         ec->gpe = tmp;
1279         /* Use the global lock for all EC transactions? */
1280         tmp = 0;
1281         acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1282         ec->global_lock = tmp;
1283         ec->handle = handle;
1284         return AE_CTRL_TERMINATE;
1285 }
1286
1287 static int ec_install_handlers(struct acpi_ec *ec)
1288 {
1289         acpi_status status;
1290
1291         acpi_ec_start(ec, false);
1292
1293         if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1294                 status = acpi_install_address_space_handler(ec->handle,
1295                                                             ACPI_ADR_SPACE_EC,
1296                                                             &acpi_ec_space_handler,
1297                                                             NULL, ec);
1298                 if (ACPI_FAILURE(status)) {
1299                         if (status == AE_NOT_FOUND) {
1300                                 /*
1301                                  * Maybe OS fails in evaluating the _REG
1302                                  * object. The AE_NOT_FOUND error will be
1303                                  * ignored and OS * continue to initialize
1304                                  * EC.
1305                                  */
1306                                 pr_err("Fail in evaluating the _REG object"
1307                                         " of EC device. Broken bios is suspected.\n");
1308                         } else {
1309                                 acpi_ec_stop(ec, false);
1310                                 return -ENODEV;
1311                         }
1312                 }
1313                 set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1314         }
1315
1316         if (!test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
1317                 status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1318                                           ACPI_GPE_EDGE_TRIGGERED,
1319                                           &acpi_ec_gpe_handler, ec);
1320                 /* This is not fatal as we can poll EC events */
1321                 if (ACPI_SUCCESS(status)) {
1322                         set_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
1323                         if (test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1324                             ec->reference_count >= 1)
1325                                 acpi_ec_enable_gpe(ec, true);
1326                 }
1327         }
1328
1329         return 0;
1330 }
1331
1332 static void ec_remove_handlers(struct acpi_ec *ec)
1333 {
1334         acpi_ec_stop(ec, false);
1335
1336         if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1337                 if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1338                                         ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1339                         pr_err("failed to remove space handler\n");
1340                 clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1341         }
1342
1343         if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
1344                 if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1345                                         &acpi_ec_gpe_handler)))
1346                         pr_err("failed to remove gpe handler\n");
1347                 clear_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
1348         }
1349 }
1350
1351 static int acpi_ec_add(struct acpi_device *device)
1352 {
1353         struct acpi_ec *ec = NULL;
1354         int ret;
1355
1356         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1357         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1358
1359         /* Check for boot EC */
1360         if (boot_ec) {
1361                 ec = boot_ec;
1362                 boot_ec = NULL;
1363                 ec_remove_handlers(ec);
1364                 if (first_ec == ec)
1365                         first_ec = NULL;
1366         } else {
1367                 ec = make_acpi_ec();
1368                 if (!ec)
1369                         return -ENOMEM;
1370         }
1371         if (ec_parse_device(device->handle, 0, ec, NULL) !=
1372                 AE_CTRL_TERMINATE) {
1373                         kfree(ec);
1374                         return -EINVAL;
1375         }
1376
1377         /* Find and register all query methods */
1378         acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1379                             acpi_ec_register_query_methods, NULL, ec, NULL);
1380
1381         if (!first_ec)
1382                 first_ec = ec;
1383         device->driver_data = ec;
1384
1385         ret = !!request_region(ec->data_addr, 1, "EC data");
1386         WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1387         ret = !!request_region(ec->command_addr, 1, "EC cmd");
1388         WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1389
1390         pr_info("GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
1391                           ec->gpe, ec->command_addr, ec->data_addr);
1392
1393         ret = ec_install_handlers(ec);
1394
1395         /* Reprobe devices depending on the EC */
1396         acpi_walk_dep_device_list(ec->handle);
1397
1398         /* EC is fully operational, allow queries */
1399         clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
1400
1401         /* Clear stale _Q events if hardware might require that */
1402         if (EC_FLAGS_CLEAR_ON_RESUME)
1403                 acpi_ec_clear(ec);
1404         return ret;
1405 }
1406
1407 static int acpi_ec_remove(struct acpi_device *device)
1408 {
1409         struct acpi_ec *ec;
1410
1411         if (!device)
1412                 return -EINVAL;
1413
1414         ec = acpi_driver_data(device);
1415         ec_remove_handlers(ec);
1416         acpi_ec_remove_query_handlers(ec, true, 0);
1417         release_region(ec->data_addr, 1);
1418         release_region(ec->command_addr, 1);
1419         device->driver_data = NULL;
1420         if (ec == first_ec)
1421                 first_ec = NULL;
1422         kfree(ec);
1423         return 0;
1424 }
1425
1426 static acpi_status
1427 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1428 {
1429         struct acpi_ec *ec = context;
1430
1431         if (resource->type != ACPI_RESOURCE_TYPE_IO)
1432                 return AE_OK;
1433
1434         /*
1435          * The first address region returned is the data port, and
1436          * the second address region returned is the status/command
1437          * port.
1438          */
1439         if (ec->data_addr == 0)
1440                 ec->data_addr = resource->data.io.minimum;
1441         else if (ec->command_addr == 0)
1442                 ec->command_addr = resource->data.io.minimum;
1443         else
1444                 return AE_CTRL_TERMINATE;
1445
1446         return AE_OK;
1447 }
1448
1449 static const struct acpi_device_id ec_device_ids[] = {
1450         {"PNP0C09", 0},
1451         {"", 0},
1452 };
1453
1454 int __init acpi_ec_dsdt_probe(void)
1455 {
1456         acpi_status status;
1457
1458         if (boot_ec)
1459                 return 0;
1460
1461         /*
1462          * Finding EC from DSDT if there is no ECDT EC available. When this
1463          * function is invoked, ACPI tables have been fully loaded, we can
1464          * walk namespace now.
1465          */
1466         boot_ec = make_acpi_ec();
1467         if (!boot_ec)
1468                 return -ENOMEM;
1469         status = acpi_get_devices(ec_device_ids[0].id,
1470                                   ec_parse_device, boot_ec, NULL);
1471         if (ACPI_FAILURE(status) || !boot_ec->handle)
1472                 return -ENODEV;
1473         if (!ec_install_handlers(boot_ec)) {
1474                 first_ec = boot_ec;
1475                 return 0;
1476         }
1477         return -EFAULT;
1478 }
1479
1480 #if 0
1481 /*
1482  * Some EC firmware variations refuses to respond QR_EC when SCI_EVT is not
1483  * set, for which case, we complete the QR_EC without issuing it to the
1484  * firmware.
1485  * https://bugzilla.kernel.org/show_bug.cgi?id=82611
1486  * https://bugzilla.kernel.org/show_bug.cgi?id=97381
1487  */
1488 static int ec_flag_query_handshake(const struct dmi_system_id *id)
1489 {
1490         pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
1491         EC_FLAGS_QUERY_HANDSHAKE = 1;
1492         return 0;
1493 }
1494 #endif
1495
1496 /*
1497  * On some hardware it is necessary to clear events accumulated by the EC during
1498  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1499  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1500  *
1501  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1502  *
1503  * Ideally, the EC should also be instructed NOT to accumulate events during
1504  * sleep (which Windows seems to do somehow), but the interface to control this
1505  * behaviour is not known at this time.
1506  *
1507  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1508  * however it is very likely that other Samsung models are affected.
1509  *
1510  * On systems which don't accumulate _Q events during sleep, this extra check
1511  * should be harmless.
1512  */
1513 static int ec_clear_on_resume(const struct dmi_system_id *id)
1514 {
1515         pr_debug("Detected system needing EC poll on resume.\n");
1516         EC_FLAGS_CLEAR_ON_RESUME = 1;
1517         ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1518         return 0;
1519 }
1520
1521 static int ec_correct_ecdt(const struct dmi_system_id *id)
1522 {
1523         pr_debug("Detected system needing ECDT address correction.\n");
1524         EC_FLAGS_CORRECT_ECDT = 1;
1525         return 0;
1526 }
1527
1528 static struct dmi_system_id ec_dmi_table[] __initdata = {
1529         {
1530         ec_correct_ecdt, "Asus L4R", {
1531         DMI_MATCH(DMI_BIOS_VERSION, "1008.006"),
1532         DMI_MATCH(DMI_PRODUCT_NAME, "L4R"),
1533         DMI_MATCH(DMI_BOARD_NAME, "L4R") }, NULL},
1534         {
1535         ec_correct_ecdt, "Asus M6R", {
1536         DMI_MATCH(DMI_BIOS_VERSION, "0207"),
1537         DMI_MATCH(DMI_PRODUCT_NAME, "M6R"),
1538         DMI_MATCH(DMI_BOARD_NAME, "M6R") }, NULL},
1539         {
1540         ec_correct_ecdt, "MSI MS-171F", {
1541         DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1542         DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
1543         {
1544         ec_clear_on_resume, "Samsung hardware", {
1545         DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1546         {},
1547 };
1548
1549 int __init acpi_ec_ecdt_probe(void)
1550 {
1551         int ret = 0;
1552         acpi_status status;
1553         struct acpi_table_ecdt *ecdt_ptr;
1554
1555         boot_ec = make_acpi_ec();
1556         if (!boot_ec)
1557                 return -ENOMEM;
1558         /*
1559          * Generate a boot ec context
1560          */
1561         dmi_check_system(ec_dmi_table);
1562         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1563                                 (struct acpi_table_header **)&ecdt_ptr);
1564         if (ACPI_FAILURE(status)) {
1565                 ret = -ENODEV;
1566                 goto error;
1567         }
1568
1569         if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
1570                 /*
1571                  * Asus X50GL:
1572                  * https://bugzilla.kernel.org/show_bug.cgi?id=11880
1573                  */
1574                 ret = -ENODEV;
1575                 goto error;
1576         }
1577
1578         pr_info("EC description table is found, configuring boot EC\n");
1579         if (EC_FLAGS_CORRECT_ECDT) {
1580                 /*
1581                  * Asus L4R, Asus M6R
1582                  * https://bugzilla.kernel.org/show_bug.cgi?id=9399
1583                  * MSI MS-171F
1584                  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1585                  */
1586                 boot_ec->command_addr = ecdt_ptr->data.address;
1587                 boot_ec->data_addr = ecdt_ptr->control.address;
1588         } else {
1589                 boot_ec->command_addr = ecdt_ptr->control.address;
1590                 boot_ec->data_addr = ecdt_ptr->data.address;
1591         }
1592         boot_ec->gpe = ecdt_ptr->gpe;
1593         boot_ec->handle = ACPI_ROOT_OBJECT;
1594         ret = ec_install_handlers(boot_ec);
1595         if (!ret)
1596                 first_ec = boot_ec;
1597 error:
1598         if (ret) {
1599                 kfree(boot_ec);
1600                 boot_ec = NULL;
1601         }
1602         return ret;
1603 }
1604
1605 static int param_set_event_clearing(const char *val, struct kernel_param *kp)
1606 {
1607         int result = 0;
1608
1609         if (!strncmp(val, "status", sizeof("status") - 1)) {
1610                 ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1611                 pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
1612         } else if (!strncmp(val, "query", sizeof("query") - 1)) {
1613                 ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
1614                 pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
1615         } else if (!strncmp(val, "event", sizeof("event") - 1)) {
1616                 ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
1617                 pr_info("Assuming SCI_EVT clearing on event reads\n");
1618         } else
1619                 result = -EINVAL;
1620         return result;
1621 }
1622
1623 static int param_get_event_clearing(char *buffer, struct kernel_param *kp)
1624 {
1625         switch (ec_event_clearing) {
1626         case ACPI_EC_EVT_TIMING_STATUS:
1627                 return sprintf(buffer, "status");
1628         case ACPI_EC_EVT_TIMING_QUERY:
1629                 return sprintf(buffer, "query");
1630         case ACPI_EC_EVT_TIMING_EVENT:
1631                 return sprintf(buffer, "event");
1632         default:
1633                 return sprintf(buffer, "invalid");
1634         }
1635         return 0;
1636 }
1637
1638 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
1639                   NULL, 0644);
1640 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
1641
1642 static struct acpi_driver acpi_ec_driver = {
1643         .name = "ec",
1644         .class = ACPI_EC_CLASS,
1645         .ids = ec_device_ids,
1646         .ops = {
1647                 .add = acpi_ec_add,
1648                 .remove = acpi_ec_remove,
1649                 },
1650 };
1651
1652 int __init acpi_ec_init(void)
1653 {
1654         int result = 0;
1655
1656         /* Now register the driver for the EC */
1657         result = acpi_bus_register_driver(&acpi_ec_driver);
1658         if (result < 0)
1659                 return -ENODEV;
1660
1661         return result;
1662 }
1663
1664 /* EC driver currently not unloadable */
1665 #if 0
1666 static void __exit acpi_ec_exit(void)
1667 {
1668
1669         acpi_bus_unregister_driver(&acpi_ec_driver);
1670 }
1671 #endif  /* 0 */