drivers/acpi/ec.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  ec.c - ACPI Embedded Controller Driver (v3)
   4  *
   5  *  Copyright (C) 2001-2015 Intel Corporation
   6  *    Author: 2014, 2015 Lv Zheng <lv.zheng@intel.com>
   7  *            2006, 2007 Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
   8  *            2006       Denis Sadykov <denis.m.sadykov@intel.com>
   9  *            2004       Luming Yu <luming.yu@intel.com>
  10  *            2001, 2002 Andy Grover <andrew.grover@intel.com>
  11  *            2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
  12  *  Copyright (C) 2008      Alexey Starikovskiy <astarikovskiy@suse.de>
  13  */
  14
  15 /* Uncomment next line to get verbose printout */
  16 /* #define DEBUG */
  17 #define pr_fmt(fmt) "ACPI: EC: " fmt
  18
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/init.h>
  22 #include <linux/types.h>
  23 #include <linux/delay.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/list.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/slab.h>
  28 #include <linux/suspend.h>
  29 #include <linux/acpi.h>
  30 #include <linux/dmi.h>
  31 #include <asm/io.h>
  32
  33 #include "internal.h"
  34
  35 #define ACPI_EC_CLASS                   "embedded_controller"
  36 #define ACPI_EC_DEVICE_NAME             "Embedded Controller"
  37
  38 /* EC status register */
  39 #define ACPI_EC_FLAG_OBF        0x01    /* Output buffer full */
  40 #define ACPI_EC_FLAG_IBF        0x02    /* Input buffer full */
  41 #define ACPI_EC_FLAG_CMD        0x08    /* Input buffer contains a command */
  42 #define ACPI_EC_FLAG_BURST      0x10    /* burst mode */
  43 #define ACPI_EC_FLAG_SCI        0x20    /* EC-SCI occurred */
  44
  45 /*
  46  * The SCI_EVT clearing timing is not defined by the ACPI specification.
  47  * This leads to lots of practical timing issues for the host EC driver.
  48  * The following variations are defined (from the target EC firmware's
  49  * perspective):
  50  * STATUS: After indicating SCI_EVT edge triggered IRQ to the host, the
  51  *         target can clear SCI_EVT at any time so long as the host can see
  52  *         the indication by reading the status register (EC_SC). So the
  53  *         host should re-check SCI_EVT after the first time the SCI_EVT
  54  *         indication is seen, which is the same time the query request
  55  *         (QR_EC) is written to the command register (EC_CMD). SCI_EVT set
  56  *         at any later time could indicate another event. Normally such
  57  *         kind of EC firmware has implemented an event queue and will
  58  *         return 0x00 to indicate "no outstanding event".
  59  * QUERY: After seeing the query request (QR_EC) written to the command
  60  *        register (EC_CMD) by the host and having prepared the responding
  61  *        event value in the data register (EC_DATA), the target can safely
  62  *        clear SCI_EVT because the target can confirm that the current
  63  *        event is being handled by the host. The host then should check
  64  *        SCI_EVT right after reading the event response from the data
  65  *        register (EC_DATA).
  66  * EVENT: After seeing the event response read from the data register
  67  *        (EC_DATA) by the host, the target can clear SCI_EVT. As the
  68  *        target requires time to notice the change in the data register
  69  *        (EC_DATA), the host may be required to wait additional guarding
  70  *        time before checking the SCI_EVT again. Such guarding may not be
  71  *        necessary if the host is notified via another IRQ.
  72  */
  73 #define ACPI_EC_EVT_TIMING_STATUS       0x00
  74 #define ACPI_EC_EVT_TIMING_QUERY        0x01
  75 #define ACPI_EC_EVT_TIMING_EVENT        0x02
  76
  77 /* EC commands */
  78 enum ec_command {
  79         ACPI_EC_COMMAND_READ = 0x80,
  80         ACPI_EC_COMMAND_WRITE = 0x81,
  81         ACPI_EC_BURST_ENABLE = 0x82,
  82         ACPI_EC_BURST_DISABLE = 0x83,
  83         ACPI_EC_COMMAND_QUERY = 0x84,
  84 };
  85
  86 #define ACPI_EC_DELAY           500     /* Wait 500ms max. during EC ops */
  87 #define ACPI_EC_UDELAY_GLK      1000    /* Wait 1ms max. to get global lock */
  88 #define ACPI_EC_UDELAY_POLL     550     /* Wait 1ms for EC transaction polling */
  89 #define ACPI_EC_CLEAR_MAX       100     /* Maximum number of events to query
  90                                          * when trying to clear the EC */
  91 #define ACPI_EC_MAX_QUERIES     16      /* Maximum number of parallel queries */
  92
  93 enum {
  94         EC_FLAGS_QUERY_ENABLED,         /* Query is enabled */
  95         EC_FLAGS_QUERY_PENDING,         /* Query is pending */
  96         EC_FLAGS_QUERY_GUARDING,        /* Guard for SCI_EVT check */
  97         EC_FLAGS_EVENT_HANDLER_INSTALLED,       /* Event handler installed */
  98         EC_FLAGS_EC_HANDLER_INSTALLED,  /* OpReg handler installed */
  99         EC_FLAGS_QUERY_METHODS_INSTALLED, /* _Qxx handlers installed */
 100         EC_FLAGS_STARTED,               /* Driver is started */
 101         EC_FLAGS_STOPPED,               /* Driver is stopped */
 102         EC_FLAGS_EVENTS_MASKED,         /* Events masked */
 103 };
 104
 105 #define ACPI_EC_COMMAND_POLL            0x01 /* Available for command byte */
 106 #define ACPI_EC_COMMAND_COMPLETE        0x02 /* Completed last byte */
 107
 108 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
 109 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
 110 module_param(ec_delay, uint, 0644);
 111 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
 112
 113 static unsigned int ec_max_queries __read_mostly = ACPI_EC_MAX_QUERIES;
 114 module_param(ec_max_queries, uint, 0644);
 115 MODULE_PARM_DESC(ec_max_queries, "Maximum parallel _Qxx evaluations");
 116
 117 static bool ec_busy_polling __read_mostly;
 118 module_param(ec_busy_polling, bool, 0644);
 119 MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction");
 120
 121 static unsigned int ec_polling_guard __read_mostly = ACPI_EC_UDELAY_POLL;
 122 module_param(ec_polling_guard, uint, 0644);
 123 MODULE_PARM_DESC(ec_polling_guard, "Guard time(us) between EC accesses in polling modes");
 124
 125 static unsigned int ec_event_clearing __read_mostly = ACPI_EC_EVT_TIMING_QUERY;
 126
 127 /*
 128  * If the number of false interrupts per one transaction exceeds
 129  * this threshold, will think there is a GPE storm happened and
 130  * will disable the GPE for normal transaction.
 131  */
 132 static unsigned int ec_storm_threshold  __read_mostly = 8;
 133 module_param(ec_storm_threshold, uint, 0644);
 134 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
 135
 136 static bool ec_freeze_events __read_mostly = false;
 137 module_param(ec_freeze_events, bool, 0644);
 138 MODULE_PARM_DESC(ec_freeze_events, "Disabling event handling during suspend/resume");
 139
 140 static bool ec_no_wakeup __read_mostly;
 141 module_param(ec_no_wakeup, bool, 0644);
 142 MODULE_PARM_DESC(ec_no_wakeup, "Do not wake up from suspend-to-idle");
 143
 144 struct acpi_ec_query_handler {
 145         struct list_head node;
 146         acpi_ec_query_func func;
 147         acpi_handle handle;
 148         void *data;
 149         u8 query_bit;
 150         struct kref kref;
 151 };
 152
 153 struct transaction {
 154         const u8 *wdata;
 155         u8 *rdata;
 156         unsigned short irq_count;
 157         u8 command;
 158         u8 wi;
 159         u8 ri;
 160         u8 wlen;
 161         u8 rlen;
 162         u8 flags;
 163 };
 164
 165 struct acpi_ec_query {
 166         struct transaction transaction;
 167         struct work_struct work;
 168         struct acpi_ec_query_handler *handler;
 169         struct acpi_ec *ec;
 170 };
 171
 172 static int acpi_ec_query(struct acpi_ec *ec, u8 *data);
 173 static void advance_transaction(struct acpi_ec *ec, bool interrupt);
 174 static void acpi_ec_event_handler(struct work_struct *work);
 175 static void acpi_ec_event_processor(struct work_struct *work);
 176
 177 struct acpi_ec *first_ec;
 178 EXPORT_SYMBOL(first_ec);
 179
 180 static struct acpi_ec *boot_ec;
 181 static bool boot_ec_is_ecdt = false;
 182 static struct workqueue_struct *ec_wq;
 183 static struct workqueue_struct *ec_query_wq;
 184
 185 static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
 186 static int EC_FLAGS_TRUST_DSDT_GPE; /* Needs DSDT GPE as correction setting */
 187 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
 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_event_enabled(struct acpi_ec *ec)
 244 {
 245         /*
 246          * There is an OSPM early stage logic. During the early stages
 247          * (boot/resume), OSPMs shouldn't enable the event handling, only
 248          * the EC transactions are allowed to be performed.
 249          */
 250         if (!test_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 251                 return false;
 252         /*
 253          * However, disabling the event handling is experimental for late
 254          * stage (suspend), and is controlled by the boot parameter of
 255          * "ec_freeze_events":
 256          * 1. true:  The EC event handling is disabled before entering
 257          *           the noirq stage.
 258          * 2. false: The EC event handling is automatically disabled as
 259          *           soon as the EC driver is stopped.
 260          */
 261         if (ec_freeze_events)
 262                 return acpi_ec_started(ec);
 263         else
 264                 return test_bit(EC_FLAGS_STARTED, &ec->flags);
 265 }
 266
 267 static bool acpi_ec_flushed(struct acpi_ec *ec)
 268 {
 269         return ec->reference_count == 1;
 270 }
 271
 272 /* --------------------------------------------------------------------------
 273  *                           EC Registers
 274  * -------------------------------------------------------------------------- */
 275
 276 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
 277 {
 278         u8 x = inb(ec->command_addr);
 279
 280         ec_dbg_raw("EC_SC(R) = 0x%2.2x "
 281                    "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
 282                    x,
 283                    !!(x & ACPI_EC_FLAG_SCI),
 284                    !!(x & ACPI_EC_FLAG_BURST),
 285                    !!(x & ACPI_EC_FLAG_CMD),
 286                    !!(x & ACPI_EC_FLAG_IBF),
 287                    !!(x & ACPI_EC_FLAG_OBF));
 288         return x;
 289 }
 290
 291 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
 292 {
 293         u8 x = inb(ec->data_addr);
 294
 295         ec->timestamp = jiffies;
 296         ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
 297         return x;
 298 }
 299
 300 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
 301 {
 302         ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
 303         outb(command, ec->command_addr);
 304         ec->timestamp = jiffies;
 305 }
 306
 307 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
 308 {
 309         ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
 310         outb(data, ec->data_addr);
 311         ec->timestamp = jiffies;
 312 }
 313
 314 #if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
 315 static const char *acpi_ec_cmd_string(u8 cmd)
 316 {
 317         switch (cmd) {
 318         case 0x80:
 319                 return "RD_EC";
 320         case 0x81:
 321                 return "WR_EC";
 322         case 0x82:
 323                 return "BE_EC";
 324         case 0x83:
 325                 return "BD_EC";
 326         case 0x84:
 327                 return "QR_EC";
 328         }
 329         return "UNKNOWN";
 330 }
 331 #else
 332 #define acpi_ec_cmd_string(cmd)         "UNDEF"
 333 #endif
 334
 335 /* --------------------------------------------------------------------------
 336  *                           GPE Registers
 337  * -------------------------------------------------------------------------- */
 338
 339 static inline bool acpi_ec_gpe_status_set(struct acpi_ec *ec)
 340 {
 341         acpi_event_status gpe_status = 0;
 342
 343         (void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
 344         return !!(gpe_status & ACPI_EVENT_FLAG_STATUS_SET);
 345 }
 346
 347 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
 348 {
 349         if (open)
 350                 acpi_enable_gpe(NULL, ec->gpe);
 351         else {
 352                 BUG_ON(ec->reference_count < 1);
 353                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
 354         }
 355         if (acpi_ec_gpe_status_set(ec)) {
 356                 /*
 357                  * On some platforms, EN=1 writes cannot trigger GPE. So
 358                  * software need to manually trigger a pseudo GPE event on
 359                  * EN=1 writes.
 360                  */
 361                 ec_dbg_raw("Polling quirk");
 362                 advance_transaction(ec, false);
 363         }
 364 }
 365
 366 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
 367 {
 368         if (close)
 369                 acpi_disable_gpe(NULL, ec->gpe);
 370         else {
 371                 BUG_ON(ec->reference_count < 1);
 372                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
 373         }
 374 }
 375
 376 /* --------------------------------------------------------------------------
 377  *                           Transaction Management
 378  * -------------------------------------------------------------------------- */
 379
 380 static void acpi_ec_submit_request(struct acpi_ec *ec)
 381 {
 382         ec->reference_count++;
 383         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
 384             ec->gpe >= 0 && ec->reference_count == 1)
 385                 acpi_ec_enable_gpe(ec, true);
 386 }
 387
 388 static void acpi_ec_complete_request(struct acpi_ec *ec)
 389 {
 390         bool flushed = false;
 391
 392         ec->reference_count--;
 393         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
 394             ec->gpe >= 0 && ec->reference_count == 0)
 395                 acpi_ec_disable_gpe(ec, true);
 396         flushed = acpi_ec_flushed(ec);
 397         if (flushed)
 398                 wake_up(&ec->wait);
 399 }
 400
 401 static void acpi_ec_mask_events(struct acpi_ec *ec)
 402 {
 403         if (!test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
 404                 if (ec->gpe >= 0)
 405                         acpi_ec_disable_gpe(ec, false);
 406                 else
 407                         disable_irq_nosync(ec->irq);
 408
 409                 ec_dbg_drv("Polling enabled");
 410                 set_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
 411         }
 412 }
 413
 414 static void acpi_ec_unmask_events(struct acpi_ec *ec)
 415 {
 416         if (test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
 417                 clear_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
 418                 if (ec->gpe >= 0)
 419                         acpi_ec_enable_gpe(ec, false);
 420                 else
 421                         enable_irq(ec->irq);
 422
 423                 ec_dbg_drv("Polling disabled");
 424         }
 425 }
 426
 427 /*
 428  * acpi_ec_submit_flushable_request() - Increase the reference count unless
 429  *                                      the flush operation is not in
 430  *                                      progress
 431  * @ec: the EC device
 432  *
 433  * This function must be used before taking a new action that should hold
 434  * the reference count.  If this function returns false, then the action
 435  * must be discarded or it will prevent the flush operation from being
 436  * completed.
 437  */
 438 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
 439 {
 440         if (!acpi_ec_started(ec))
 441                 return false;
 442         acpi_ec_submit_request(ec);
 443         return true;
 444 }
 445
 446 static void acpi_ec_submit_query(struct acpi_ec *ec)
 447 {
 448         acpi_ec_mask_events(ec);
 449         if (!acpi_ec_event_enabled(ec))
 450                 return;
 451         if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
 452                 ec_dbg_evt("Command(%s) submitted/blocked",
 453                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 454                 ec->nr_pending_queries++;
 455                 ec->events_in_progress++;
 456                 queue_work(ec_wq, &ec->work);
 457         }
 458 }
 459
 460 static void acpi_ec_complete_query(struct acpi_ec *ec)
 461 {
 462         if (test_and_clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
 463                 ec_dbg_evt("Command(%s) unblocked",
 464                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 465         acpi_ec_unmask_events(ec);
 466 }
 467
 468 static inline void __acpi_ec_enable_event(struct acpi_ec *ec)
 469 {
 470         if (!test_and_set_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 471                 ec_log_drv("event unblocked");
 472         /*
 473          * Unconditionally invoke this once after enabling the event
 474          * handling mechanism to detect the pending events.
 475          */
 476         advance_transaction(ec, false);
 477 }
 478
 479 static inline void __acpi_ec_disable_event(struct acpi_ec *ec)
 480 {
 481         if (test_and_clear_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 482                 ec_log_drv("event blocked");
 483 }
 484
 485 /*
 486  * Process _Q events that might have accumulated in the EC.
 487  * Run with locked ec mutex.
 488  */
 489 static void acpi_ec_clear(struct acpi_ec *ec)
 490 {
 491         int i, status;
 492         u8 value = 0;
 493
 494         for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
 495                 status = acpi_ec_query(ec, &value);
 496                 if (status || !value)
 497                         break;
 498         }
 499         if (unlikely(i == ACPI_EC_CLEAR_MAX))
 500                 pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
 501         else
 502                 pr_info("%d stale EC events cleared\n", i);
 503 }
 504
 505 static void acpi_ec_enable_event(struct acpi_ec *ec)
 506 {
 507         unsigned long flags;
 508
 509         spin_lock_irqsave(&ec->lock, flags);
 510         if (acpi_ec_started(ec))
 511                 __acpi_ec_enable_event(ec);
 512         spin_unlock_irqrestore(&ec->lock, flags);
 513
 514         /* Drain additional events if hardware requires that */
 515         if (EC_FLAGS_CLEAR_ON_RESUME)
 516                 acpi_ec_clear(ec);
 517 }
 518
 519 #ifdef CONFIG_PM_SLEEP
 520 static void __acpi_ec_flush_work(void)
 521 {
 522         flush_workqueue(ec_wq); /* flush ec->work */
 523         flush_workqueue(ec_query_wq); /* flush queries */
 524 }
 525
 526 static void acpi_ec_disable_event(struct acpi_ec *ec)
 527 {
 528         unsigned long flags;
 529
 530         spin_lock_irqsave(&ec->lock, flags);
 531         __acpi_ec_disable_event(ec);
 532         spin_unlock_irqrestore(&ec->lock, flags);
 533
 534         /*
 535          * When ec_freeze_events is true, we need to flush events in
 536          * the proper position before entering the noirq stage.
 537          */
 538         __acpi_ec_flush_work();
 539 }
 540
 541 void acpi_ec_flush_work(void)
 542 {
 543         /* Without ec_wq there is nothing to flush. */
 544         if (!ec_wq)
 545                 return;
 546
 547         __acpi_ec_flush_work();
 548 }
 549 #endif /* CONFIG_PM_SLEEP */
 550
 551 static bool acpi_ec_guard_event(struct acpi_ec *ec)
 552 {
 553         bool guarded = true;
 554         unsigned long flags;
 555
 556         spin_lock_irqsave(&ec->lock, flags);
 557         /*
 558          * If firmware SCI_EVT clearing timing is "event", we actually
 559          * don't know when the SCI_EVT will be cleared by firmware after
 560          * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
 561          * acceptable period.
 562          *
 563          * The guarding period begins when EC_FLAGS_QUERY_PENDING is
 564          * flagged, which means SCI_EVT check has just been performed.
 565          * But if the current transaction is ACPI_EC_COMMAND_QUERY, the
 566          * guarding should have already been performed (via
 567          * EC_FLAGS_QUERY_GUARDING) and should not be applied so that the
 568          * ACPI_EC_COMMAND_QUERY transaction can be transitioned into
 569          * ACPI_EC_COMMAND_POLL state immediately.
 570          */
 571         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
 572             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY ||
 573             !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) ||
 574             (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY))
 575                 guarded = false;
 576         spin_unlock_irqrestore(&ec->lock, flags);
 577         return guarded;
 578 }
 579
 580 static int ec_transaction_polled(struct acpi_ec *ec)
 581 {
 582         unsigned long flags;
 583         int ret = 0;
 584
 585         spin_lock_irqsave(&ec->lock, flags);
 586         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
 587                 ret = 1;
 588         spin_unlock_irqrestore(&ec->lock, flags);
 589         return ret;
 590 }
 591
 592 static int ec_transaction_completed(struct acpi_ec *ec)
 593 {
 594         unsigned long flags;
 595         int ret = 0;
 596
 597         spin_lock_irqsave(&ec->lock, flags);
 598         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
 599                 ret = 1;
 600         spin_unlock_irqrestore(&ec->lock, flags);
 601         return ret;
 602 }
 603
 604 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
 605 {
 606         ec->curr->flags |= flag;
 607         if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
 608                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS &&
 609                     flag == ACPI_EC_COMMAND_POLL)
 610                         acpi_ec_complete_query(ec);
 611                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY &&
 612                     flag == ACPI_EC_COMMAND_COMPLETE)
 613                         acpi_ec_complete_query(ec);
 614                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 615                     flag == ACPI_EC_COMMAND_COMPLETE)
 616                         set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
 617         }
 618 }
 619
 620 static void acpi_ec_spurious_interrupt(struct acpi_ec *ec, struct transaction *t)
 621 {
 622         if (t->irq_count < ec_storm_threshold)
 623                 ++t->irq_count;
 624
 625         /* Trigger if the threshold is 0 too. */
 626         if (t->irq_count == ec_storm_threshold)
 627                 acpi_ec_mask_events(ec);
 628 }
 629
 630 static void advance_transaction(struct acpi_ec *ec, bool interrupt)
 631 {
 632         struct transaction *t = ec->curr;
 633         bool wakeup = false;
 634         u8 status;
 635
 636         ec_dbg_stm("%s (%d)", interrupt ? "IRQ" : "TASK", smp_processor_id());
 637
 638         /*
 639          * Clear GPE_STS upfront to allow subsequent hardware GPE_STS 0->1
 640          * changes to always trigger a GPE interrupt.
 641          *
 642          * GPE STS is a W1C register, which means:
 643          *
 644          * 1. Software can clear it without worrying about clearing the other
 645          *    GPEs' STS bits when the hardware sets them in parallel.
 646          *
 647          * 2. As long as software can ensure only clearing it when it is set,
 648          *    hardware won't set it in parallel.
 649          */
 650         if (ec->gpe >= 0 && acpi_ec_gpe_status_set(ec))
 651                 acpi_clear_gpe(NULL, ec->gpe);
 652
 653         status = acpi_ec_read_status(ec);
 654
 655         /*
 656          * Another IRQ or a guarded polling mode advancement is detected,
 657          * the next QR_EC submission is then allowed.
 658          */
 659         if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
 660                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 661                     (!ec->nr_pending_queries ||
 662                      test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) {
 663                         clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
 664                         acpi_ec_complete_query(ec);
 665                 }
 666                 if (!t)
 667                         goto out;
 668         }
 669
 670         if (t->flags & ACPI_EC_COMMAND_POLL) {
 671                 if (t->wlen > t->wi) {
 672                         if (!(status & ACPI_EC_FLAG_IBF))
 673                                 acpi_ec_write_data(ec, t->wdata[t->wi++]);
 674                         else if (interrupt && !(status & ACPI_EC_FLAG_SCI))
 675                                 acpi_ec_spurious_interrupt(ec, t);
 676                 } else if (t->rlen > t->ri) {
 677                         if (status & ACPI_EC_FLAG_OBF) {
 678                                 t->rdata[t->ri++] = acpi_ec_read_data(ec);
 679                                 if (t->rlen == t->ri) {
 680                                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 681                                         wakeup = true;
 682                                         if (t->command == ACPI_EC_COMMAND_QUERY)
 683                                                 ec_dbg_evt("Command(%s) completed by hardware",
 684                                                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 685                                 }
 686                         } else if (interrupt && !(status & ACPI_EC_FLAG_SCI)) {
 687                                 acpi_ec_spurious_interrupt(ec, t);
 688                         }
 689                 } else if (t->wlen == t->wi && !(status & ACPI_EC_FLAG_IBF)) {
 690                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 691                         wakeup = true;
 692                 }
 693         } else if (!(status & ACPI_EC_FLAG_IBF)) {
 694                 acpi_ec_write_cmd(ec, t->command);
 695                 ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
 696         }
 697
 698 out:
 699         if (status & ACPI_EC_FLAG_SCI)
 700                 acpi_ec_submit_query(ec);
 701
 702         if (wakeup && interrupt)
 703                 wake_up(&ec->wait);
 704 }
 705
 706 static void start_transaction(struct acpi_ec *ec)
 707 {
 708         ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
 709         ec->curr->flags = 0;
 710 }
 711
 712 static int ec_guard(struct acpi_ec *ec)
 713 {
 714         unsigned long guard = usecs_to_jiffies(ec->polling_guard);
 715         unsigned long timeout = ec->timestamp + guard;
 716
 717         /* Ensure guarding period before polling EC status */
 718         do {
 719                 if (ec->busy_polling) {
 720                         /* Perform busy polling */
 721                         if (ec_transaction_completed(ec))
 722                                 return 0;
 723                         udelay(jiffies_to_usecs(guard));
 724                 } else {
 725                         /*
 726                          * Perform wait polling
 727                          * 1. Wait the transaction to be completed by the
 728                          *    GPE handler after the transaction enters
 729                          *    ACPI_EC_COMMAND_POLL state.
 730                          * 2. A special guarding logic is also required
 731                          *    for event clearing mode "event" before the
 732                          *    transaction enters ACPI_EC_COMMAND_POLL
 733                          *    state.
 734                          */
 735                         if (!ec_transaction_polled(ec) &&
 736                             !acpi_ec_guard_event(ec))
 737                                 break;
 738                         if (wait_event_timeout(ec->wait,
 739                                                ec_transaction_completed(ec),
 740                                                guard))
 741                                 return 0;
 742                 }
 743         } while (time_before(jiffies, timeout));
 744         return -ETIME;
 745 }
 746
 747 static int ec_poll(struct acpi_ec *ec)
 748 {
 749         unsigned long flags;
 750         int repeat = 5; /* number of command restarts */
 751
 752         while (repeat--) {
 753                 unsigned long delay = jiffies +
 754                         msecs_to_jiffies(ec_delay);
 755                 do {
 756                         if (!ec_guard(ec))
 757                                 return 0;
 758                         spin_lock_irqsave(&ec->lock, flags);
 759                         advance_transaction(ec, false);
 760                         spin_unlock_irqrestore(&ec->lock, flags);
 761                 } while (time_before(jiffies, delay));
 762                 pr_debug("controller reset, restart transaction\n");
 763                 spin_lock_irqsave(&ec->lock, flags);
 764                 start_transaction(ec);
 765                 spin_unlock_irqrestore(&ec->lock, flags);
 766         }
 767         return -ETIME;
 768 }
 769
 770 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
 771                                         struct transaction *t)
 772 {
 773         unsigned long tmp;
 774         int ret = 0;
 775
 776         /* start transaction */
 777         spin_lock_irqsave(&ec->lock, tmp);
 778         /* Enable GPE for command processing (IBF=0/OBF=1) */
 779         if (!acpi_ec_submit_flushable_request(ec)) {
 780                 ret = -EINVAL;
 781                 goto unlock;
 782         }
 783         ec_dbg_ref(ec, "Increase command");
 784         /* following two actions should be kept atomic */
 785         ec->curr = t;
 786         ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
 787         start_transaction(ec);
 788         spin_unlock_irqrestore(&ec->lock, tmp);
 789
 790         ret = ec_poll(ec);
 791
 792         spin_lock_irqsave(&ec->lock, tmp);
 793         if (t->irq_count == ec_storm_threshold)
 794                 acpi_ec_unmask_events(ec);
 795         ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
 796         ec->curr = NULL;
 797         /* Disable GPE for command processing (IBF=0/OBF=1) */
 798         acpi_ec_complete_request(ec);
 799         ec_dbg_ref(ec, "Decrease command");
 800 unlock:
 801         spin_unlock_irqrestore(&ec->lock, tmp);
 802         return ret;
 803 }
 804
 805 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
 806 {
 807         int status;
 808         u32 glk;
 809
 810         if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
 811                 return -EINVAL;
 812         if (t->rdata)
 813                 memset(t->rdata, 0, t->rlen);
 814
 815         mutex_lock(&ec->mutex);
 816         if (ec->global_lock) {
 817                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
 818                 if (ACPI_FAILURE(status)) {
 819                         status = -ENODEV;
 820                         goto unlock;
 821                 }
 822         }
 823
 824         status = acpi_ec_transaction_unlocked(ec, t);
 825
 826         if (ec->global_lock)
 827                 acpi_release_global_lock(glk);
 828 unlock:
 829         mutex_unlock(&ec->mutex);
 830         return status;
 831 }
 832
 833 static int acpi_ec_burst_enable(struct acpi_ec *ec)
 834 {
 835         u8 d;
 836         struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
 837                                 .wdata = NULL, .rdata = &d,
 838                                 .wlen = 0, .rlen = 1};
 839
 840         return acpi_ec_transaction(ec, &t);
 841 }
 842
 843 static int acpi_ec_burst_disable(struct acpi_ec *ec)
 844 {
 845         struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
 846                                 .wdata = NULL, .rdata = NULL,
 847                                 .wlen = 0, .rlen = 0};
 848
 849         return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
 850                                 acpi_ec_transaction(ec, &t) : 0;
 851 }
 852
 853 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
 854 {
 855         int result;
 856         u8 d;
 857         struct transaction t = {.command = ACPI_EC_COMMAND_READ,
 858                                 .wdata = &address, .rdata = &d,
 859                                 .wlen = 1, .rlen = 1};
 860
 861         result = acpi_ec_transaction(ec, &t);
 862         *data = d;
 863         return result;
 864 }
 865
 866 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
 867 {
 868         u8 wdata[2] = { address, data };
 869         struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
 870                                 .wdata = wdata, .rdata = NULL,
 871                                 .wlen = 2, .rlen = 0};
 872
 873         return acpi_ec_transaction(ec, &t);
 874 }
 875
 876 int ec_read(u8 addr, u8 *val)
 877 {
 878         int err;
 879         u8 temp_data;
 880
 881         if (!first_ec)
 882                 return -ENODEV;
 883
 884         err = acpi_ec_read(first_ec, addr, &temp_data);
 885
 886         if (!err) {
 887                 *val = temp_data;
 888                 return 0;
 889         }
 890         return err;
 891 }
 892 EXPORT_SYMBOL(ec_read);
 893
 894 int ec_write(u8 addr, u8 val)
 895 {
 896         int err;
 897
 898         if (!first_ec)
 899                 return -ENODEV;
 900
 901         err = acpi_ec_write(first_ec, addr, val);
 902
 903         return err;
 904 }
 905 EXPORT_SYMBOL(ec_write);
 906
 907 int ec_transaction(u8 command,
 908                    const u8 *wdata, unsigned wdata_len,
 909                    u8 *rdata, unsigned rdata_len)
 910 {
 911         struct transaction t = {.command = command,
 912                                 .wdata = wdata, .rdata = rdata,
 913                                 .wlen = wdata_len, .rlen = rdata_len};
 914
 915         if (!first_ec)
 916                 return -ENODEV;
 917
 918         return acpi_ec_transaction(first_ec, &t);
 919 }
 920 EXPORT_SYMBOL(ec_transaction);
 921
 922 /* Get the handle to the EC device */
 923 acpi_handle ec_get_handle(void)
 924 {
 925         if (!first_ec)
 926                 return NULL;
 927         return first_ec->handle;
 928 }
 929 EXPORT_SYMBOL(ec_get_handle);
 930
 931 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
 932 {
 933         unsigned long flags;
 934
 935         spin_lock_irqsave(&ec->lock, flags);
 936         if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
 937                 ec_dbg_drv("Starting EC");
 938                 /* Enable GPE for event processing (SCI_EVT=1) */
 939                 if (!resuming) {
 940                         acpi_ec_submit_request(ec);
 941                         ec_dbg_ref(ec, "Increase driver");
 942                 }
 943                 ec_log_drv("EC started");
 944         }
 945         spin_unlock_irqrestore(&ec->lock, flags);
 946 }
 947
 948 static bool acpi_ec_stopped(struct acpi_ec *ec)
 949 {
 950         unsigned long flags;
 951         bool flushed;
 952
 953         spin_lock_irqsave(&ec->lock, flags);
 954         flushed = acpi_ec_flushed(ec);
 955         spin_unlock_irqrestore(&ec->lock, flags);
 956         return flushed;
 957 }
 958
 959 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
 960 {
 961         unsigned long flags;
 962
 963         spin_lock_irqsave(&ec->lock, flags);
 964         if (acpi_ec_started(ec)) {
 965                 ec_dbg_drv("Stopping EC");
 966                 set_bit(EC_FLAGS_STOPPED, &ec->flags);
 967                 spin_unlock_irqrestore(&ec->lock, flags);
 968                 wait_event(ec->wait, acpi_ec_stopped(ec));
 969                 spin_lock_irqsave(&ec->lock, flags);
 970                 /* Disable GPE for event processing (SCI_EVT=1) */
 971                 if (!suspending) {
 972                         acpi_ec_complete_request(ec);
 973                         ec_dbg_ref(ec, "Decrease driver");
 974                 } else if (!ec_freeze_events)
 975                         __acpi_ec_disable_event(ec);
 976                 clear_bit(EC_FLAGS_STARTED, &ec->flags);
 977                 clear_bit(EC_FLAGS_STOPPED, &ec->flags);
 978                 ec_log_drv("EC stopped");
 979         }
 980         spin_unlock_irqrestore(&ec->lock, flags);
 981 }
 982
 983 static void acpi_ec_enter_noirq(struct acpi_ec *ec)
 984 {
 985         unsigned long flags;
 986
 987         spin_lock_irqsave(&ec->lock, flags);
 988         ec->busy_polling = true;
 989         ec->polling_guard = 0;
 990         ec_log_drv("interrupt blocked");
 991         spin_unlock_irqrestore(&ec->lock, flags);
 992 }
 993
 994 static void acpi_ec_leave_noirq(struct acpi_ec *ec)
 995 {
 996         unsigned long flags;
 997
 998         spin_lock_irqsave(&ec->lock, flags);
 999         ec->busy_polling = ec_busy_polling;
1000         ec->polling_guard = ec_polling_guard;
1001         ec_log_drv("interrupt unblocked");
1002         spin_unlock_irqrestore(&ec->lock, flags);
1003 }
1004
1005 void acpi_ec_block_transactions(void)
1006 {
1007         struct acpi_ec *ec = first_ec;
1008
1009         if (!ec)
1010                 return;
1011
1012         mutex_lock(&ec->mutex);
1013         /* Prevent transactions from being carried out */
1014         acpi_ec_stop(ec, true);
1015         mutex_unlock(&ec->mutex);
1016 }
1017
1018 void acpi_ec_unblock_transactions(void)
1019 {
1020         /*
1021          * Allow transactions to happen again (this function is called from
1022          * atomic context during wakeup, so we don't need to acquire the mutex).
1023          */
1024         if (first_ec)
1025                 acpi_ec_start(first_ec, true);
1026 }
1027
1028 /* --------------------------------------------------------------------------
1029                                 Event Management
1030    -------------------------------------------------------------------------- */
1031 static struct acpi_ec_query_handler *
1032 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
1033 {
1034         struct acpi_ec_query_handler *handler;
1035
1036         mutex_lock(&ec->mutex);
1037         list_for_each_entry(handler, &ec->list, node) {
1038                 if (value == handler->query_bit) {
1039                         kref_get(&handler->kref);
1040                         mutex_unlock(&ec->mutex);
1041                         return handler;
1042                 }
1043         }
1044         mutex_unlock(&ec->mutex);
1045         return NULL;
1046 }
1047
1048 static void acpi_ec_query_handler_release(struct kref *kref)
1049 {
1050         struct acpi_ec_query_handler *handler =
1051                 container_of(kref, struct acpi_ec_query_handler, kref);
1052
1053         kfree(handler);
1054 }
1055
1056 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
1057 {
1058         kref_put(&handler->kref, acpi_ec_query_handler_release);
1059 }
1060
1061 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
1062                               acpi_handle handle, acpi_ec_query_func func,
1063                               void *data)
1064 {
1065         struct acpi_ec_query_handler *handler =
1066             kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
1067
1068         if (!handler)
1069                 return -ENOMEM;
1070
1071         handler->query_bit = query_bit;
1072         handler->handle = handle;
1073         handler->func = func;
1074         handler->data = data;
1075         mutex_lock(&ec->mutex);
1076         kref_init(&handler->kref);
1077         list_add(&handler->node, &ec->list);
1078         mutex_unlock(&ec->mutex);
1079         return 0;
1080 }
1081 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1082
1083 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1084                                           bool remove_all, u8 query_bit)
1085 {
1086         struct acpi_ec_query_handler *handler, *tmp;
1087         LIST_HEAD(free_list);
1088
1089         mutex_lock(&ec->mutex);
1090         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1091                 if (remove_all || query_bit == handler->query_bit) {
1092                         list_del_init(&handler->node);
1093                         list_add(&handler->node, &free_list);
1094                 }
1095         }
1096         mutex_unlock(&ec->mutex);
1097         list_for_each_entry_safe(handler, tmp, &free_list, node)
1098                 acpi_ec_put_query_handler(handler);
1099 }
1100
1101 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1102 {
1103         acpi_ec_remove_query_handlers(ec, false, query_bit);
1104 }
1105 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1106
1107 static struct acpi_ec_query *acpi_ec_create_query(struct acpi_ec *ec, u8 *pval)
1108 {
1109         struct acpi_ec_query *q;
1110         struct transaction *t;
1111
1112         q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1113         if (!q)
1114                 return NULL;
1115
1116         INIT_WORK(&q->work, acpi_ec_event_processor);
1117         t = &q->transaction;
1118         t->command = ACPI_EC_COMMAND_QUERY;
1119         t->rdata = pval;
1120         t->rlen = 1;
1121         q->ec = ec;
1122         return q;
1123 }
1124
1125 static void acpi_ec_delete_query(struct acpi_ec_query *q)
1126 {
1127         if (q) {
1128                 if (q->handler)
1129                         acpi_ec_put_query_handler(q->handler);
1130                 kfree(q);
1131         }
1132 }
1133
1134 static void acpi_ec_event_processor(struct work_struct *work)
1135 {
1136         struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1137         struct acpi_ec_query_handler *handler = q->handler;
1138         struct acpi_ec *ec = q->ec;
1139
1140         ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1141
1142         if (handler->func)
1143                 handler->func(handler->data);
1144         else if (handler->handle)
1145                 acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1146
1147         ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1148
1149         spin_lock_irq(&ec->lock);
1150         ec->queries_in_progress--;
1151         spin_unlock_irq(&ec->lock);
1152
1153         acpi_ec_delete_query(q);
1154 }
1155
1156 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
1157 {
1158         u8 value = 0;
1159         int result;
1160         struct acpi_ec_query *q;
1161
1162         q = acpi_ec_create_query(ec, &value);
1163         if (!q)
1164                 return -ENOMEM;
1165
1166         /*
1167          * Query the EC to find out which _Qxx method we need to evaluate.
1168          * Note that successful completion of the query causes the ACPI_EC_SCI
1169          * bit to be cleared (and thus clearing the interrupt source).
1170          */
1171         result = acpi_ec_transaction(ec, &q->transaction);
1172         if (!value)
1173                 result = -ENODATA;
1174         if (result)
1175                 goto err_exit;
1176
1177         q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1178         if (!q->handler) {
1179                 result = -ENODATA;
1180                 goto err_exit;
1181         }
1182
1183         /*
1184          * It is reported that _Qxx are evaluated in a parallel way on Windows:
1185          * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1186          *
1187          * Put this log entry before queue_work() to make it appear in the log
1188          * before any other messages emitted during workqueue handling.
1189          */
1190         ec_dbg_evt("Query(0x%02x) scheduled", value);
1191
1192         spin_lock_irq(&ec->lock);
1193
1194         ec->queries_in_progress++;
1195         queue_work(ec_query_wq, &q->work);
1196
1197         spin_unlock_irq(&ec->lock);
1198
1199 err_exit:
1200         if (result)
1201                 acpi_ec_delete_query(q);
1202         if (data)
1203                 *data = value;
1204         return result;
1205 }
1206
1207 static void acpi_ec_check_event(struct acpi_ec *ec)
1208 {
1209         unsigned long flags;
1210
1211         if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1212                 if (ec_guard(ec)) {
1213                         spin_lock_irqsave(&ec->lock, flags);
1214                         /*
1215                          * Take care of the SCI_EVT unless no one else is
1216                          * taking care of it.
1217                          */
1218                         if (!ec->curr)
1219                                 advance_transaction(ec, false);
1220                         spin_unlock_irqrestore(&ec->lock, flags);
1221                 }
1222         }
1223 }
1224
1225 static void acpi_ec_event_handler(struct work_struct *work)
1226 {
1227         unsigned long flags;
1228         struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1229
1230         ec_dbg_evt("Event started");
1231
1232         spin_lock_irqsave(&ec->lock, flags);
1233         while (ec->nr_pending_queries) {
1234                 spin_unlock_irqrestore(&ec->lock, flags);
1235                 (void)acpi_ec_query(ec, NULL);
1236                 spin_lock_irqsave(&ec->lock, flags);
1237                 ec->nr_pending_queries--;
1238                 /*
1239                  * Before exit, make sure that this work item can be
1240                  * scheduled again. There might be QR_EC failures, leaving
1241                  * EC_FLAGS_QUERY_PENDING uncleared and preventing this work
1242                  * item from being scheduled again.
1243                  */
1244                 if (!ec->nr_pending_queries) {
1245                         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
1246                             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY)
1247                                 acpi_ec_complete_query(ec);
1248                 }
1249         }
1250         spin_unlock_irqrestore(&ec->lock, flags);
1251
1252         ec_dbg_evt("Event stopped");
1253
1254         acpi_ec_check_event(ec);
1255
1256         spin_lock_irqsave(&ec->lock, flags);
1257         ec->events_in_progress--;
1258         spin_unlock_irqrestore(&ec->lock, flags);
1259 }
1260
1261 static void acpi_ec_handle_interrupt(struct acpi_ec *ec)
1262 {
1263         unsigned long flags;
1264
1265         spin_lock_irqsave(&ec->lock, flags);
1266         advance_transaction(ec, true);
1267         spin_unlock_irqrestore(&ec->lock, flags);
1268 }
1269
1270 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1271                                u32 gpe_number, void *data)
1272 {
1273         acpi_ec_handle_interrupt(data);
1274         return ACPI_INTERRUPT_HANDLED;
1275 }
1276
1277 static irqreturn_t acpi_ec_irq_handler(int irq, void *data)
1278 {
1279         acpi_ec_handle_interrupt(data);
1280         return IRQ_HANDLED;
1281 }
1282
1283 /* --------------------------------------------------------------------------
1284  *                           Address Space Management
1285  * -------------------------------------------------------------------------- */
1286
1287 static acpi_status
1288 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1289                       u32 bits, u64 *value64,
1290                       void *handler_context, void *region_context)
1291 {
1292         struct acpi_ec *ec = handler_context;
1293         int result = 0, i, bytes = bits / 8;
1294         u8 *value = (u8 *)value64;
1295
1296         if ((address > 0xFF) || !value || !handler_context)
1297                 return AE_BAD_PARAMETER;
1298
1299         if (function != ACPI_READ && function != ACPI_WRITE)
1300                 return AE_BAD_PARAMETER;
1301
1302         if (ec->busy_polling || bits > 8)
1303                 acpi_ec_burst_enable(ec);
1304
1305         for (i = 0; i < bytes; ++i, ++address, ++value)
1306                 result = (function == ACPI_READ) ?
1307                         acpi_ec_read(ec, address, value) :
1308                         acpi_ec_write(ec, address, *value);
1309
1310         if (ec->busy_polling || bits > 8)
1311                 acpi_ec_burst_disable(ec);
1312
1313         switch (result) {
1314         case -EINVAL:
1315                 return AE_BAD_PARAMETER;
1316         case -ENODEV:
1317                 return AE_NOT_FOUND;
1318         case -ETIME:
1319                 return AE_TIME;
1320         default:
1321                 return AE_OK;
1322         }
1323 }
1324
1325 /* --------------------------------------------------------------------------
1326  *                             Driver Interface
1327  * -------------------------------------------------------------------------- */
1328
1329 static acpi_status
1330 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1331
1332 static void acpi_ec_free(struct acpi_ec *ec)
1333 {
1334         if (first_ec == ec)
1335                 first_ec = NULL;
1336         if (boot_ec == ec)
1337                 boot_ec = NULL;
1338         kfree(ec);
1339 }
1340
1341 static struct acpi_ec *acpi_ec_alloc(void)
1342 {
1343         struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1344
1345         if (!ec)
1346                 return NULL;
1347         mutex_init(&ec->mutex);
1348         init_waitqueue_head(&ec->wait);
1349         INIT_LIST_HEAD(&ec->list);
1350         spin_lock_init(&ec->lock);
1351         INIT_WORK(&ec->work, acpi_ec_event_handler);
1352         ec->timestamp = jiffies;
1353         ec->busy_polling = true;
1354         ec->polling_guard = 0;
1355         ec->gpe = -1;
1356         ec->irq = -1;
1357         return ec;
1358 }
1359
1360 static acpi_status
1361 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1362                                void *context, void **return_value)
1363 {
1364         char node_name[5];
1365         struct acpi_buffer buffer = { sizeof(node_name), node_name };
1366         struct acpi_ec *ec = context;
1367         int value = 0;
1368         acpi_status status;
1369
1370         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1371
1372         if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1373                 acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1374         return AE_OK;
1375 }
1376
1377 static acpi_status
1378 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1379 {
1380         acpi_status status;
1381         unsigned long long tmp = 0;
1382         struct acpi_ec *ec = context;
1383
1384         /* clear addr values, ec_parse_io_ports depend on it */
1385         ec->command_addr = ec->data_addr = 0;
1386
1387         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1388                                      ec_parse_io_ports, ec);
1389         if (ACPI_FAILURE(status))
1390                 return status;
1391         if (ec->data_addr == 0 || ec->command_addr == 0)
1392                 return AE_OK;
1393
1394         /* Get GPE bit assignment (EC events). */
1395         /* TODO: Add support for _GPE returning a package */
1396         status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1397         if (ACPI_SUCCESS(status))
1398                 ec->gpe = tmp;
1399         /*
1400          * Errors are non-fatal, allowing for ACPI Reduced Hardware
1401          * platforms which use GpioInt instead of GPE.
1402          */
1403
1404         /* Use the global lock for all EC transactions? */
1405         tmp = 0;
1406         acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1407         ec->global_lock = tmp;
1408         ec->handle = handle;
1409         return AE_CTRL_TERMINATE;
1410 }
1411
1412 static bool install_gpe_event_handler(struct acpi_ec *ec)
1413 {
1414         acpi_status status;
1415
1416         status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1417                                               ACPI_GPE_EDGE_TRIGGERED,
1418                                               &acpi_ec_gpe_handler, ec);
1419         if (ACPI_FAILURE(status))
1420                 return false;
1421
1422         if (test_bit(EC_FLAGS_STARTED, &ec->flags) && ec->reference_count >= 1)
1423                 acpi_ec_enable_gpe(ec, true);
1424
1425         return true;
1426 }
1427
1428 static bool install_gpio_irq_event_handler(struct acpi_ec *ec)
1429 {
1430         return request_irq(ec->irq, acpi_ec_irq_handler, IRQF_SHARED,
1431                            "ACPI EC", ec) >= 0;
1432 }
1433
1434 /**
1435  * ec_install_handlers - Install service callbacks and register query methods.
1436  * @ec: Target EC.
1437  * @device: ACPI device object corresponding to @ec.
1438  *
1439  * Install a handler for the EC address space type unless it has been installed
1440  * already.  If @device is not NULL, also look for EC query methods in the
1441  * namespace and register them, and install an event (either GPE or GPIO IRQ)
1442  * handler for the EC, if possible.
1443  *
1444  * Return:
1445  * -ENODEV if the address space handler cannot be installed, which means
1446  *  "unable to handle transactions",
1447  * -EPROBE_DEFER if GPIO IRQ acquisition needs to be deferred,
1448  * or 0 (success) otherwise.
1449  */
1450 static int ec_install_handlers(struct acpi_ec *ec, struct acpi_device *device)
1451 {
1452         acpi_status status;
1453
1454         acpi_ec_start(ec, false);
1455
1456         if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1457                 acpi_ec_enter_noirq(ec);
1458                 status = acpi_install_address_space_handler(ec->handle,
1459                                                             ACPI_ADR_SPACE_EC,
1460                                                             &acpi_ec_space_handler,
1461                                                             NULL, ec);
1462                 if (ACPI_FAILURE(status)) {
1463                         acpi_ec_stop(ec, false);
1464                         return -ENODEV;
1465                 }
1466                 set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1467         }
1468
1469         if (!device)
1470                 return 0;
1471
1472         if (ec->gpe < 0) {
1473                 /* ACPI reduced hardware platforms use a GpioInt from _CRS. */
1474                 int irq = acpi_dev_gpio_irq_get(device, 0);
1475                 /*
1476                  * Bail out right away for deferred probing or complete the
1477                  * initialization regardless of any other errors.
1478                  */
1479                 if (irq == -EPROBE_DEFER)
1480                         return -EPROBE_DEFER;
1481                 else if (irq >= 0)
1482                         ec->irq = irq;
1483         }
1484
1485         if (!test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1486                 /* Find and register all query methods */
1487                 acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1488                                     acpi_ec_register_query_methods,
1489                                     NULL, ec, NULL);
1490                 set_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1491         }
1492         if (!test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1493                 bool ready = false;
1494
1495                 if (ec->gpe >= 0)
1496                         ready = install_gpe_event_handler(ec);
1497                 else if (ec->irq >= 0)
1498                         ready = install_gpio_irq_event_handler(ec);
1499
1500                 if (ready) {
1501                         set_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1502                         acpi_ec_leave_noirq(ec);
1503                 }
1504                 /*
1505                  * Failures to install an event handler are not fatal, because
1506                  * the EC can be polled for events.
1507                  */
1508         }
1509         /* EC is fully operational, allow queries */
1510         acpi_ec_enable_event(ec);
1511
1512         return 0;
1513 }
1514
1515 static void ec_remove_handlers(struct acpi_ec *ec)
1516 {
1517         if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1518                 if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1519                                         ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1520                         pr_err("failed to remove space handler\n");
1521                 clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1522         }
1523
1524         /*
1525          * Stops handling the EC transactions after removing the operation
1526          * region handler. This is required because _REG(DISCONNECT)
1527          * invoked during the removal can result in new EC transactions.
1528          *
1529          * Flushes the EC requests and thus disables the GPE before
1530          * removing the GPE handler. This is required by the current ACPICA
1531          * GPE core. ACPICA GPE core will automatically disable a GPE when
1532          * it is indicated but there is no way to handle it. So the drivers
1533          * must disable the GPEs prior to removing the GPE handlers.
1534          */
1535         acpi_ec_stop(ec, false);
1536
1537         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1538                 if (ec->gpe >= 0 &&
1539                     ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1540                                  &acpi_ec_gpe_handler)))
1541                         pr_err("failed to remove gpe handler\n");
1542
1543                 if (ec->irq >= 0)
1544                         free_irq(ec->irq, ec);
1545
1546                 clear_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1547         }
1548         if (test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1549                 acpi_ec_remove_query_handlers(ec, true, 0);
1550                 clear_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1551         }
1552 }
1553
1554 static int acpi_ec_setup(struct acpi_ec *ec, struct acpi_device *device)
1555 {
1556         int ret;
1557
1558         ret = ec_install_handlers(ec, device);
1559         if (ret)
1560                 return ret;
1561
1562         /* First EC capable of handling transactions */
1563         if (!first_ec)
1564                 first_ec = ec;
1565
1566         pr_info("EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n", ec->command_addr,
1567                 ec->data_addr);
1568
1569         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1570                 if (ec->gpe >= 0)
1571                         pr_info("GPE=0x%x\n", ec->gpe);
1572                 else
1573                         pr_info("IRQ=%d\n", ec->irq);
1574         }
1575
1576         return ret;
1577 }
1578
1579 static int acpi_ec_add(struct acpi_device *device)
1580 {
1581         struct acpi_ec *ec;
1582         int ret;
1583
1584         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1585         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1586
1587         if (boot_ec && (boot_ec->handle == device->handle ||
1588             !strcmp(acpi_device_hid(device), ACPI_ECDT_HID))) {
1589                 /* Fast path: this device corresponds to the boot EC. */
1590                 ec = boot_ec;
1591         } else {
1592                 acpi_status status;
1593
1594                 ec = acpi_ec_alloc();
1595                 if (!ec)
1596                         return -ENOMEM;
1597
1598                 status = ec_parse_device(device->handle, 0, ec, NULL);
1599                 if (status != AE_CTRL_TERMINATE) {
1600                         ret = -EINVAL;
1601                         goto err;
1602                 }
1603
1604                 if (boot_ec && ec->command_addr == boot_ec->command_addr &&
1605                     ec->data_addr == boot_ec->data_addr &&
1606                     !EC_FLAGS_TRUST_DSDT_GPE) {
1607                         /*
1608                          * Trust PNP0C09 namespace location rather than
1609                          * ECDT ID. But trust ECDT GPE rather than _GPE
1610                          * because of ASUS quirks, so do not change
1611                          * boot_ec->gpe to ec->gpe.
1612                          */
1613                         boot_ec->handle = ec->handle;
1614                         acpi_handle_debug(ec->handle, "duplicated.\n");
1615                         acpi_ec_free(ec);
1616                         ec = boot_ec;
1617                 }
1618         }
1619
1620         ret = acpi_ec_setup(ec, device);
1621         if (ret)
1622                 goto err;
1623
1624         if (ec == boot_ec)
1625                 acpi_handle_info(boot_ec->handle,
1626                                  "Boot %s EC initialization complete\n",
1627                                  boot_ec_is_ecdt ? "ECDT" : "DSDT");
1628
1629         acpi_handle_info(ec->handle,
1630                          "EC: Used to handle transactions and events\n");
1631
1632         device->driver_data = ec;
1633
1634         ret = !!request_region(ec->data_addr, 1, "EC data");
1635         WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1636         ret = !!request_region(ec->command_addr, 1, "EC cmd");
1637         WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1638
1639         /* Reprobe devices depending on the EC */
1640         acpi_dev_clear_dependencies(device);
1641
1642         acpi_handle_debug(ec->handle, "enumerated.\n");
1643         return 0;
1644
1645 err:
1646         if (ec != boot_ec)
1647                 acpi_ec_free(ec);
1648
1649         return ret;
1650 }
1651
1652 static int acpi_ec_remove(struct acpi_device *device)
1653 {
1654         struct acpi_ec *ec;
1655
1656         if (!device)
1657                 return -EINVAL;
1658
1659         ec = acpi_driver_data(device);
1660         release_region(ec->data_addr, 1);
1661         release_region(ec->command_addr, 1);
1662         device->driver_data = NULL;
1663         if (ec != boot_ec) {
1664                 ec_remove_handlers(ec);
1665                 acpi_ec_free(ec);
1666         }
1667         return 0;
1668 }
1669
1670 static acpi_status
1671 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1672 {
1673         struct acpi_ec *ec = context;
1674
1675         if (resource->type != ACPI_RESOURCE_TYPE_IO)
1676                 return AE_OK;
1677
1678         /*
1679          * The first address region returned is the data port, and
1680          * the second address region returned is the status/command
1681          * port.
1682          */
1683         if (ec->data_addr == 0)
1684                 ec->data_addr = resource->data.io.minimum;
1685         else if (ec->command_addr == 0)
1686                 ec->command_addr = resource->data.io.minimum;
1687         else
1688                 return AE_CTRL_TERMINATE;
1689
1690         return AE_OK;
1691 }
1692
1693 static const struct acpi_device_id ec_device_ids[] = {
1694         {"PNP0C09", 0},
1695         {ACPI_ECDT_HID, 0},
1696         {"", 0},
1697 };
1698
1699 /*
1700  * This function is not Windows-compatible as Windows never enumerates the
1701  * namespace EC before the main ACPI device enumeration process. It is
1702  * retained for historical reason and will be deprecated in the future.
1703  */
1704 void __init acpi_ec_dsdt_probe(void)
1705 {
1706         struct acpi_ec *ec;
1707         acpi_status status;
1708         int ret;
1709
1710         /*
1711          * If a platform has ECDT, there is no need to proceed as the
1712          * following probe is not a part of the ACPI device enumeration,
1713          * executing _STA is not safe, and thus this probe may risk of
1714          * picking up an invalid EC device.
1715          */
1716         if (boot_ec)
1717                 return;
1718
1719         ec = acpi_ec_alloc();
1720         if (!ec)
1721                 return;
1722
1723         /*
1724          * At this point, the namespace is initialized, so start to find
1725          * the namespace objects.
1726          */
1727         status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device, ec, NULL);
1728         if (ACPI_FAILURE(status) || !ec->handle) {
1729                 acpi_ec_free(ec);
1730                 return;
1731         }
1732
1733         /*
1734          * When the DSDT EC is available, always re-configure boot EC to
1735          * have _REG evaluated. _REG can only be evaluated after the
1736          * namespace initialization.
1737          * At this point, the GPE is not fully initialized, so do not to
1738          * handle the events.
1739          */
1740         ret = acpi_ec_setup(ec, NULL);
1741         if (ret) {
1742                 acpi_ec_free(ec);
1743                 return;
1744         }
1745
1746         boot_ec = ec;
1747
1748         acpi_handle_info(ec->handle,
1749                          "Boot DSDT EC used to handle transactions\n");
1750 }
1751
1752 /*
1753  * acpi_ec_ecdt_start - Finalize the boot ECDT EC initialization.
1754  *
1755  * First, look for an ACPI handle for the boot ECDT EC if acpi_ec_add() has not
1756  * found a matching object in the namespace.
1757  *
1758  * Next, in case the DSDT EC is not functioning, it is still necessary to
1759  * provide a functional ECDT EC to handle events, so add an extra device object
1760  * to represent it (see https://bugzilla.kernel.org/show_bug.cgi?id=115021).
1761  *
1762  * This is useful on platforms with valid ECDT and invalid DSDT EC settings,
1763  * like ASUS X550ZE (see https://bugzilla.kernel.org/show_bug.cgi?id=196847).
1764  */
1765 static void __init acpi_ec_ecdt_start(void)
1766 {
1767         struct acpi_table_ecdt *ecdt_ptr;
1768         acpi_handle handle;
1769         acpi_status status;
1770
1771         /* Bail out if a matching EC has been found in the namespace. */
1772         if (!boot_ec || boot_ec->handle != ACPI_ROOT_OBJECT)
1773                 return;
1774
1775         /* Look up the object pointed to from the ECDT in the namespace. */
1776         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1777                                 (struct acpi_table_header **)&ecdt_ptr);
1778         if (ACPI_FAILURE(status))
1779                 return;
1780
1781         status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
1782         if (ACPI_SUCCESS(status)) {
1783                 boot_ec->handle = handle;
1784
1785                 /* Add a special ACPI device object to represent the boot EC. */
1786                 acpi_bus_register_early_device(ACPI_BUS_TYPE_ECDT_EC);
1787         }
1788
1789         acpi_put_table((struct acpi_table_header *)ecdt_ptr);
1790 }
1791
1792 /*
1793  * On some hardware it is necessary to clear events accumulated by the EC during
1794  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1795  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1796  *
1797  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1798  *
1799  * Ideally, the EC should also be instructed NOT to accumulate events during
1800  * sleep (which Windows seems to do somehow), but the interface to control this
1801  * behaviour is not known at this time.
1802  *
1803  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1804  * however it is very likely that other Samsung models are affected.
1805  *
1806  * On systems which don't accumulate _Q events during sleep, this extra check
1807  * should be harmless.
1808  */
1809 static int ec_clear_on_resume(const struct dmi_system_id *id)
1810 {
1811         pr_debug("Detected system needing EC poll on resume.\n");
1812         EC_FLAGS_CLEAR_ON_RESUME = 1;
1813         ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1814         return 0;
1815 }
1816
1817 /*
1818  * Some ECDTs contain wrong register addresses.
1819  * MSI MS-171F
1820  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1821  */
1822 static int ec_correct_ecdt(const struct dmi_system_id *id)
1823 {
1824         pr_debug("Detected system needing ECDT address correction.\n");
1825         EC_FLAGS_CORRECT_ECDT = 1;
1826         return 0;
1827 }
1828
1829 /*
1830  * Some ECDTs contain wrong GPE setting, but they share the same port addresses
1831  * with DSDT EC, don't duplicate the DSDT EC with ECDT EC in this case.
1832  * https://bugzilla.kernel.org/show_bug.cgi?id=209989
1833  */
1834 static int ec_honor_dsdt_gpe(const struct dmi_system_id *id)
1835 {
1836         pr_debug("Detected system needing DSDT GPE setting.\n");
1837         EC_FLAGS_TRUST_DSDT_GPE = 1;
1838         return 0;
1839 }
1840
1841 static const struct dmi_system_id ec_dmi_table[] __initconst = {
1842         {
1843         ec_correct_ecdt, "MSI MS-171F", {
1844         DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1845         DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
1846         {
1847         /* https://bugzilla.kernel.org/show_bug.cgi?id=209989 */
1848         ec_honor_dsdt_gpe, "HP Pavilion Gaming Laptop 15-cx0xxx", {
1849         DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1850         DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion Gaming Laptop 15-cx0xxx"),}, NULL},
1851         {
1852         ec_clear_on_resume, "Samsung hardware", {
1853         DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1854         {},
1855 };
1856
1857 void __init acpi_ec_ecdt_probe(void)
1858 {
1859         struct acpi_table_ecdt *ecdt_ptr;
1860         struct acpi_ec *ec;
1861         acpi_status status;
1862         int ret;
1863
1864         /* Generate a boot ec context. */
1865         dmi_check_system(ec_dmi_table);
1866         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1867                                 (struct acpi_table_header **)&ecdt_ptr);
1868         if (ACPI_FAILURE(status))
1869                 return;
1870
1871         if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
1872                 /*
1873                  * Asus X50GL:
1874                  * https://bugzilla.kernel.org/show_bug.cgi?id=11880
1875                  */
1876                 goto out;
1877         }
1878
1879         ec = acpi_ec_alloc();
1880         if (!ec)
1881                 goto out;
1882
1883         if (EC_FLAGS_CORRECT_ECDT) {
1884                 ec->command_addr = ecdt_ptr->data.address;
1885                 ec->data_addr = ecdt_ptr->control.address;
1886         } else {
1887                 ec->command_addr = ecdt_ptr->control.address;
1888                 ec->data_addr = ecdt_ptr->data.address;
1889         }
1890
1891         /*
1892          * Ignore the GPE value on Reduced Hardware platforms.
1893          * Some products have this set to an erroneous value.
1894          */
1895         if (!acpi_gbl_reduced_hardware)
1896                 ec->gpe = ecdt_ptr->gpe;
1897
1898         ec->handle = ACPI_ROOT_OBJECT;
1899
1900         /*
1901          * At this point, the namespace is not initialized, so do not find
1902          * the namespace objects, or handle the events.
1903          */
1904         ret = acpi_ec_setup(ec, NULL);
1905         if (ret) {
1906                 acpi_ec_free(ec);
1907                 goto out;
1908         }
1909
1910         boot_ec = ec;
1911         boot_ec_is_ecdt = true;
1912
1913         pr_info("Boot ECDT EC used to handle transactions\n");
1914
1915 out:
1916         acpi_put_table((struct acpi_table_header *)ecdt_ptr);
1917 }
1918
1919 #ifdef CONFIG_PM_SLEEP
1920 static int acpi_ec_suspend(struct device *dev)
1921 {
1922         struct acpi_ec *ec =
1923                 acpi_driver_data(to_acpi_device(dev));
1924
1925         if (!pm_suspend_no_platform() && ec_freeze_events)
1926                 acpi_ec_disable_event(ec);
1927         return 0;
1928 }
1929
1930 static int acpi_ec_suspend_noirq(struct device *dev)
1931 {
1932         struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
1933
1934         /*
1935          * The SCI handler doesn't run at this point, so the GPE can be
1936          * masked at the low level without side effects.
1937          */
1938         if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1939             ec->gpe >= 0 && ec->reference_count >= 1)
1940                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
1941
1942         acpi_ec_enter_noirq(ec);
1943
1944         return 0;
1945 }
1946
1947 static int acpi_ec_resume_noirq(struct device *dev)
1948 {
1949         struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
1950
1951         acpi_ec_leave_noirq(ec);
1952
1953         if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1954             ec->gpe >= 0 && ec->reference_count >= 1)
1955                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
1956
1957         return 0;
1958 }
1959
1960 static int acpi_ec_resume(struct device *dev)
1961 {
1962         struct acpi_ec *ec =
1963                 acpi_driver_data(to_acpi_device(dev));
1964
1965         acpi_ec_enable_event(ec);
1966         return 0;
1967 }
1968
1969 void acpi_ec_mark_gpe_for_wake(void)
1970 {
1971         if (first_ec && !ec_no_wakeup)
1972                 acpi_mark_gpe_for_wake(NULL, first_ec->gpe);
1973 }
1974 EXPORT_SYMBOL_GPL(acpi_ec_mark_gpe_for_wake);
1975
1976 void acpi_ec_set_gpe_wake_mask(u8 action)
1977 {
1978         if (pm_suspend_no_platform() && first_ec && !ec_no_wakeup)
1979                 acpi_set_gpe_wake_mask(NULL, first_ec->gpe, action);
1980 }
1981
1982 bool acpi_ec_dispatch_gpe(void)
1983 {
1984         bool work_in_progress;
1985         u32 ret;
1986
1987         if (!first_ec)
1988                 return acpi_any_gpe_status_set(U32_MAX);
1989
1990         /*
1991          * Report wakeup if the status bit is set for any enabled GPE other
1992          * than the EC one.
1993          */
1994         if (acpi_any_gpe_status_set(first_ec->gpe))
1995                 return true;
1996
1997         /*
1998          * Dispatch the EC GPE in-band, but do not report wakeup in any case
1999          * to allow the caller to process events properly after that.
2000          */
2001         ret = acpi_dispatch_gpe(NULL, first_ec->gpe);
2002         if (ret == ACPI_INTERRUPT_HANDLED)
2003                 pm_pr_dbg("ACPI EC GPE dispatched\n");
2004
2005         /* Drain EC work. */
2006         do {
2007                 acpi_ec_flush_work();
2008
2009                 pm_pr_dbg("ACPI EC work flushed\n");
2010
2011                 spin_lock_irq(&first_ec->lock);
2012
2013                 work_in_progress = first_ec->events_in_progress +
2014                         first_ec->queries_in_progress > 0;
2015
2016                 spin_unlock_irq(&first_ec->lock);
2017         } while (work_in_progress && !pm_wakeup_pending());
2018
2019         return false;
2020 }
2021 #endif /* CONFIG_PM_SLEEP */
2022
2023 static const struct dev_pm_ops acpi_ec_pm = {
2024         SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq)
2025         SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
2026 };
2027
2028 static int param_set_event_clearing(const char *val,
2029                                     const struct kernel_param *kp)
2030 {
2031         int result = 0;
2032
2033         if (!strncmp(val, "status", sizeof("status") - 1)) {
2034                 ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
2035                 pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
2036         } else if (!strncmp(val, "query", sizeof("query") - 1)) {
2037                 ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
2038                 pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
2039         } else if (!strncmp(val, "event", sizeof("event") - 1)) {
2040                 ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
2041                 pr_info("Assuming SCI_EVT clearing on event reads\n");
2042         } else
2043                 result = -EINVAL;
2044         return result;
2045 }
2046
2047 static int param_get_event_clearing(char *buffer,
2048                                     const struct kernel_param *kp)
2049 {
2050         switch (ec_event_clearing) {
2051         case ACPI_EC_EVT_TIMING_STATUS:
2052                 return sprintf(buffer, "status\n");
2053         case ACPI_EC_EVT_TIMING_QUERY:
2054                 return sprintf(buffer, "query\n");
2055         case ACPI_EC_EVT_TIMING_EVENT:
2056                 return sprintf(buffer, "event\n");
2057         default:
2058                 return sprintf(buffer, "invalid\n");
2059         }
2060         return 0;
2061 }
2062
2063 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
2064                   NULL, 0644);
2065 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
2066
2067 static struct acpi_driver acpi_ec_driver = {
2068         .name = "ec",
2069         .class = ACPI_EC_CLASS,
2070         .ids = ec_device_ids,
2071         .ops = {
2072                 .add = acpi_ec_add,
2073                 .remove = acpi_ec_remove,
2074                 },
2075         .drv.pm = &acpi_ec_pm,
2076 };
2077
2078 static void acpi_ec_destroy_workqueues(void)
2079 {
2080         if (ec_wq) {
2081                 destroy_workqueue(ec_wq);
2082                 ec_wq = NULL;
2083         }
2084         if (ec_query_wq) {
2085                 destroy_workqueue(ec_query_wq);
2086                 ec_query_wq = NULL;
2087         }
2088 }
2089
2090 static int acpi_ec_init_workqueues(void)
2091 {
2092         if (!ec_wq)
2093                 ec_wq = alloc_ordered_workqueue("kec", 0);
2094
2095         if (!ec_query_wq)
2096                 ec_query_wq = alloc_workqueue("kec_query", 0, ec_max_queries);
2097
2098         if (!ec_wq || !ec_query_wq) {
2099                 acpi_ec_destroy_workqueues();
2100                 return -ENODEV;
2101         }
2102         return 0;
2103 }
2104
2105 static const struct dmi_system_id acpi_ec_no_wakeup[] = {
2106         {
2107                 .ident = "Thinkpad X1 Carbon 6th",
2108                 .matches = {
2109                         DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2110                         DMI_MATCH(DMI_PRODUCT_FAMILY, "Thinkpad X1 Carbon 6th"),
2111                 },
2112         },
2113         {
2114                 .ident = "ThinkPad X1 Yoga 3rd",
2115                 .matches = {
2116                         DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2117                         DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Yoga 3rd"),
2118                 },
2119         },
2120         { },
2121 };
2122
2123 void __init acpi_ec_init(void)
2124 {
2125         int result;
2126
2127         result = acpi_ec_init_workqueues();
2128         if (result)
2129                 return;
2130
2131         /*
2132          * Disable EC wakeup on following systems to prevent periodic
2133          * wakeup from EC GPE.
2134          */
2135         if (dmi_check_system(acpi_ec_no_wakeup)) {
2136                 ec_no_wakeup = true;
2137                 pr_debug("Disabling EC wakeup on suspend-to-idle\n");
2138         }
2139
2140         /* Driver must be registered after acpi_ec_init_workqueues(). */
2141         acpi_bus_register_driver(&acpi_ec_driver);
2142
2143         acpi_ec_ecdt_start();
2144 }
2145
2146 /* EC driver currently not unloadable */
2147 #if 0
2148 static void __exit acpi_ec_exit(void)
2149 {
2150
2151         acpi_bus_unregister_driver(&acpi_ec_driver);
2152         acpi_ec_destroy_workqueues();
2153 }
2154 #endif  /* 0 */