/* * ec.c - ACPI Embedded Controller Driver (v3) * * Copyright (C) 2001-2015 Intel Corporation * Author: 2014, 2015 Lv Zheng * 2006, 2007 Alexey Starikovskiy * 2006 Denis Sadykov * 2004 Luming Yu * 2001, 2002 Andy Grover * 2001, 2002 Paul Diefenbaugh * Copyright (C) 2008 Alexey Starikovskiy * * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or (at * your option) any later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. * * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */ /* Uncomment next line to get verbose printout */ /* #define DEBUG */ #define pr_fmt(fmt) "ACPI : EC: " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include "internal.h" #define ACPI_EC_CLASS "embedded_controller" #define ACPI_EC_DEVICE_NAME "Embedded Controller" #define ACPI_EC_FILE_INFO "info" /* EC status register */ #define ACPI_EC_FLAG_OBF 0x01 /* Output buffer full */ #define ACPI_EC_FLAG_IBF 0x02 /* Input buffer full */ #define ACPI_EC_FLAG_CMD 0x08 /* Input buffer contains a command */ #define ACPI_EC_FLAG_BURST 0x10 /* burst mode */ #define ACPI_EC_FLAG_SCI 0x20 /* EC-SCI occurred */ /* * The SCI_EVT clearing timing is not defined by the ACPI specification. * This leads to lots of practical timing issues for the host EC driver. * The following variations are defined (from the target EC firmware's * perspective): * STATUS: After indicating SCI_EVT edge triggered IRQ to the host, the * target can clear SCI_EVT at any time so long as the host can see * the indication by reading the status register (EC_SC). So the * host should re-check SCI_EVT after the first time the SCI_EVT * indication is seen, which is the same time the query request * (QR_EC) is written to the command register (EC_CMD). SCI_EVT set * at any later time could indicate another event. Normally such * kind of EC firmware has implemented an event queue and will * return 0x00 to indicate "no outstanding event". * QUERY: After seeing the query request (QR_EC) written to the command * register (EC_CMD) by the host and having prepared the responding * event value in the data register (EC_DATA), the target can safely * clear SCI_EVT because the target can confirm that the current * event is being handled by the host. The host then should check * SCI_EVT right after reading the event response from the data * register (EC_DATA). * EVENT: After seeing the event response read from the data register * (EC_DATA) by the host, the target can clear SCI_EVT. As the * target requires time to notice the change in the data register * (EC_DATA), the host may be required to wait additional guarding * time before checking the SCI_EVT again. Such guarding may not be * necessary if the host is notified via another IRQ. */ #define ACPI_EC_EVT_TIMING_STATUS 0x00 #define ACPI_EC_EVT_TIMING_QUERY 0x01 #define ACPI_EC_EVT_TIMING_EVENT 0x02 /* EC commands */ enum ec_command { ACPI_EC_COMMAND_READ = 0x80, ACPI_EC_COMMAND_WRITE = 0x81, ACPI_EC_BURST_ENABLE = 0x82, ACPI_EC_BURST_DISABLE = 0x83, ACPI_EC_COMMAND_QUERY = 0x84, }; #define ACPI_EC_DELAY 500 /* Wait 500ms max. during EC ops */ #define ACPI_EC_UDELAY_GLK 1000 /* Wait 1ms max. to get global lock */ #define ACPI_EC_UDELAY_POLL 550 /* Wait 1ms for EC transaction polling */ #define ACPI_EC_CLEAR_MAX 100 /* Maximum number of events to query * when trying to clear the EC */ enum { EC_FLAGS_QUERY_PENDING, /* Query is pending */ EC_FLAGS_QUERY_GUARDING, /* Guard for SCI_EVT check */ EC_FLAGS_HANDLERS_INSTALLED, /* Handlers for GPE and * OpReg are installed */ EC_FLAGS_STARTED, /* Driver is started */ EC_FLAGS_STOPPED, /* Driver is stopped */ EC_FLAGS_COMMAND_STORM, /* GPE storms occurred to the * current command processing */ }; #define ACPI_EC_COMMAND_POLL 0x01 /* Available for command byte */ #define ACPI_EC_COMMAND_COMPLETE 0x02 /* Completed last byte */ /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */ static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY; module_param(ec_delay, uint, 0644); MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes"); static bool ec_busy_polling __read_mostly; module_param(ec_busy_polling, bool, 0644); MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction"); static unsigned int ec_polling_guard __read_mostly = ACPI_EC_UDELAY_POLL; module_param(ec_polling_guard, uint, 0644); MODULE_PARM_DESC(ec_polling_guard, "Guard time(us) between EC accesses in polling modes"); static unsigned int ec_event_clearing __read_mostly = ACPI_EC_EVT_TIMING_STATUS; /* * If the number of false interrupts per one transaction exceeds * this threshold, will think there is a GPE storm happened and * will disable the GPE for normal transaction. */ static unsigned int ec_storm_threshold __read_mostly = 8; module_param(ec_storm_threshold, uint, 0644); MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm"); struct acpi_ec_query_handler { struct list_head node; acpi_ec_query_func func; acpi_handle handle; void *data; u8 query_bit; struct kref kref; }; struct transaction { const u8 *wdata; u8 *rdata; unsigned short irq_count; u8 command; u8 wi; u8 ri; u8 wlen; u8 rlen; u8 flags; }; static int acpi_ec_query(struct acpi_ec *ec, u8 *data); static void advance_transaction(struct acpi_ec *ec); struct acpi_ec *boot_ec, *first_ec; EXPORT_SYMBOL(first_ec); static int EC_FLAGS_VALIDATE_ECDT; /* ASUStec ECDTs need to be validated */ static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */ static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */ static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */ /* -------------------------------------------------------------------------- * Logging/Debugging * -------------------------------------------------------------------------- */ /* * Splitters used by the developers to track the boundary of the EC * handling processes. */ #ifdef DEBUG #define EC_DBG_SEP " " #define EC_DBG_DRV "+++++" #define EC_DBG_STM "=====" #define EC_DBG_REQ "*****" #define EC_DBG_EVT "#####" #else #define EC_DBG_SEP "" #define EC_DBG_DRV #define EC_DBG_STM #define EC_DBG_REQ #define EC_DBG_EVT #endif #define ec_log_raw(fmt, ...) \ pr_info(fmt "\n", ##__VA_ARGS__) #define ec_dbg_raw(fmt, ...) \ pr_debug(fmt "\n", ##__VA_ARGS__) #define ec_log(filter, fmt, ...) \ ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__) #define ec_dbg(filter, fmt, ...) \ ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__) #define ec_log_drv(fmt, ...) \ ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__) #define ec_dbg_drv(fmt, ...) \ ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__) #define ec_dbg_stm(fmt, ...) \ ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__) #define ec_dbg_req(fmt, ...) \ ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__) #define ec_dbg_evt(fmt, ...) \ ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__) #define ec_dbg_ref(ec, fmt, ...) \ ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__) /* -------------------------------------------------------------------------- * Device Flags * -------------------------------------------------------------------------- */ static bool acpi_ec_started(struct acpi_ec *ec) { return test_bit(EC_FLAGS_STARTED, &ec->flags) && !test_bit(EC_FLAGS_STOPPED, &ec->flags); } static bool acpi_ec_flushed(struct acpi_ec *ec) { return ec->reference_count == 1; } /* -------------------------------------------------------------------------- * EC Registers * -------------------------------------------------------------------------- */ static inline u8 acpi_ec_read_status(struct acpi_ec *ec) { u8 x = inb(ec->command_addr); ec_dbg_raw("EC_SC(R) = 0x%2.2x " "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d", x, !!(x & ACPI_EC_FLAG_SCI), !!(x & ACPI_EC_FLAG_BURST), !!(x & ACPI_EC_FLAG_CMD), !!(x & ACPI_EC_FLAG_IBF), !!(x & ACPI_EC_FLAG_OBF)); return x; } static inline u8 acpi_ec_read_data(struct acpi_ec *ec) { u8 x = inb(ec->data_addr); ec->timestamp = jiffies; ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x); return x; } static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command) { ec_dbg_raw("EC_SC(W) = 0x%2.2x", command); outb(command, ec->command_addr); ec->timestamp = jiffies; } static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data) { ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data); outb(data, ec->data_addr); ec->timestamp = jiffies; } #ifdef DEBUG static const char *acpi_ec_cmd_string(u8 cmd) { switch (cmd) { case 0x80: return "RD_EC"; case 0x81: return "WR_EC"; case 0x82: return "BE_EC"; case 0x83: return "BD_EC"; case 0x84: return "QR_EC"; } return "UNKNOWN"; } #else #define acpi_ec_cmd_string(cmd) "UNDEF" #endif /* -------------------------------------------------------------------------- * GPE Registers * -------------------------------------------------------------------------- */ static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec) { acpi_event_status gpe_status = 0; (void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status); return (gpe_status & ACPI_EVENT_FLAG_STATUS_SET) ? true : false; } static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open) { if (open) acpi_enable_gpe(NULL, ec->gpe); else { BUG_ON(ec->reference_count < 1); acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE); } if (acpi_ec_is_gpe_raised(ec)) { /* * On some platforms, EN=1 writes cannot trigger GPE. So * software need to manually trigger a pseudo GPE event on * EN=1 writes. */ ec_dbg_raw("Polling quirk"); advance_transaction(ec); } } static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close) { if (close) acpi_disable_gpe(NULL, ec->gpe); else { BUG_ON(ec->reference_count < 1); acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE); } } static inline void acpi_ec_clear_gpe(struct acpi_ec *ec) { /* * GPE STS is a W1C register, which means: * 1. Software can clear it without worrying about clearing other * GPEs' STS bits when the hardware sets them in parallel. * 2. As long as software can ensure only clearing it when it is * set, hardware won't set it in parallel. * So software can clear GPE in any contexts. * Warning: do not move the check into advance_transaction() as the * EC commands will be sent without GPE raised. */ if (!acpi_ec_is_gpe_raised(ec)) return; acpi_clear_gpe(NULL, ec->gpe); } /* -------------------------------------------------------------------------- * Transaction Management * -------------------------------------------------------------------------- */ static void acpi_ec_submit_request(struct acpi_ec *ec) { ec->reference_count++; if (ec->reference_count == 1) acpi_ec_enable_gpe(ec, true); } static void acpi_ec_complete_request(struct acpi_ec *ec) { bool flushed = false; ec->reference_count--; if (ec->reference_count == 0) acpi_ec_disable_gpe(ec, true); flushed = acpi_ec_flushed(ec); if (flushed) wake_up(&ec->wait); } static void acpi_ec_set_storm(struct acpi_ec *ec, u8 flag) { if (!test_bit(flag, &ec->flags)) { acpi_ec_disable_gpe(ec, false); ec_dbg_drv("Polling enabled"); set_bit(flag, &ec->flags); } } static void acpi_ec_clear_storm(struct acpi_ec *ec, u8 flag) { if (test_bit(flag, &ec->flags)) { clear_bit(flag, &ec->flags); acpi_ec_enable_gpe(ec, false); ec_dbg_drv("Polling disabled"); } } /* * acpi_ec_submit_flushable_request() - Increase the reference count unless * the flush operation is not in * progress * @ec: the EC device * * This function must be used before taking a new action that should hold * the reference count. If this function returns false, then the action * must be discarded or it will prevent the flush operation from being * completed. */ static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec) { if (!acpi_ec_started(ec)) return false; acpi_ec_submit_request(ec); return true; } static void acpi_ec_submit_query(struct acpi_ec *ec) { if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) { ec_dbg_evt("Command(%s) submitted/blocked", acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY)); ec->nr_pending_queries++; schedule_work(&ec->work); } } static void acpi_ec_complete_query(struct acpi_ec *ec) { if (test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) { clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags); ec_dbg_evt("Command(%s) unblocked", acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY)); } } static bool acpi_ec_guard_event(struct acpi_ec *ec) { if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS || ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY || !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) || (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY)) return false; /* * Postpone the query submission to allow the firmware to proceed, * we shouldn't check SCI_EVT before the firmware reflagging it. */ return true; } static int ec_transaction_polled(struct acpi_ec *ec) { unsigned long flags; int ret = 0; spin_lock_irqsave(&ec->lock, flags); if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL)) ret = 1; spin_unlock_irqrestore(&ec->lock, flags); return ret; } static int ec_transaction_completed(struct acpi_ec *ec) { unsigned long flags; int ret = 0; spin_lock_irqsave(&ec->lock, flags); if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE)) ret = 1; spin_unlock_irqrestore(&ec->lock, flags); return ret; } static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag) { ec->curr->flags |= flag; if (ec->curr->command == ACPI_EC_COMMAND_QUERY) { if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS && flag == ACPI_EC_COMMAND_POLL) acpi_ec_complete_query(ec); if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY && flag == ACPI_EC_COMMAND_COMPLETE) acpi_ec_complete_query(ec); if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT && flag == ACPI_EC_COMMAND_COMPLETE) set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags); } } static void advance_transaction(struct acpi_ec *ec) { struct transaction *t; u8 status; bool wakeup = false; ec_dbg_stm("%s (%d)", in_interrupt() ? "IRQ" : "TASK", smp_processor_id()); /* * By always clearing STS before handling all indications, we can * ensure a hardware STS 0->1 change after this clearing can always * trigger a GPE interrupt. */ acpi_ec_clear_gpe(ec); status = acpi_ec_read_status(ec); t = ec->curr; /* * Another IRQ or a guarded polling mode advancement is detected, * the next QR_EC submission is then allowed. */ if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) { if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT && test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags)) { clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags); acpi_ec_complete_query(ec); } } if (!t) goto err; if (t->flags & ACPI_EC_COMMAND_POLL) { if (t->wlen > t->wi) { if ((status & ACPI_EC_FLAG_IBF) == 0) acpi_ec_write_data(ec, t->wdata[t->wi++]); else goto err; } else if (t->rlen > t->ri) { if ((status & ACPI_EC_FLAG_OBF) == 1) { t->rdata[t->ri++] = acpi_ec_read_data(ec); if (t->rlen == t->ri) { ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE); if (t->command == ACPI_EC_COMMAND_QUERY) ec_dbg_evt("Command(%s) completed by hardware", acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY)); wakeup = true; } } else goto err; } else if (t->wlen == t->wi && (status & ACPI_EC_FLAG_IBF) == 0) { ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE); wakeup = true; } goto out; } else { if (EC_FLAGS_QUERY_HANDSHAKE && !(status & ACPI_EC_FLAG_SCI) && (t->command == ACPI_EC_COMMAND_QUERY)) { ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL); t->rdata[t->ri++] = 0x00; ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE); ec_dbg_evt("Command(%s) completed by software", acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY)); wakeup = true; } else if ((status & ACPI_EC_FLAG_IBF) == 0) { acpi_ec_write_cmd(ec, t->command); ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL); } else goto err; goto out; } err: /* * If SCI bit is set, then don't think it's a false IRQ * otherwise will take a not handled IRQ as a false one. */ if (!(status & ACPI_EC_FLAG_SCI)) { if (in_interrupt() && t) { if (t->irq_count < ec_storm_threshold) ++t->irq_count; /* Allow triggering on 0 threshold */ if (t->irq_count == ec_storm_threshold) acpi_ec_set_storm(ec, EC_FLAGS_COMMAND_STORM); } } out: if (status & ACPI_EC_FLAG_SCI) acpi_ec_submit_query(ec); if (wakeup && in_interrupt()) wake_up(&ec->wait); } static void start_transaction(struct acpi_ec *ec) { ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0; ec->curr->flags = 0; } static int ec_guard(struct acpi_ec *ec) { unsigned long guard = usecs_to_jiffies(ec_polling_guard); unsigned long timeout = ec->timestamp + guard; do { if (ec_busy_polling) { /* Perform busy polling */ if (ec_transaction_completed(ec)) return 0; udelay(jiffies_to_usecs(guard)); } else { /* * Perform wait polling * * For SCI_EVT clearing timing of "event", * performing guarding before re-checking the * SCI_EVT. Otherwise, such guarding is not needed * due to the old practices. */ if (!ec_transaction_polled(ec) && !acpi_ec_guard_event(ec)) break; if (wait_event_timeout(ec->wait, ec_transaction_completed(ec), guard)) return 0; } /* Guard the register accesses for the polling modes */ } while (time_before(jiffies, timeout)); return -ETIME; } static int ec_poll(struct acpi_ec *ec) { unsigned long flags; int repeat = 5; /* number of command restarts */ while (repeat--) { unsigned long delay = jiffies + msecs_to_jiffies(ec_delay); do { if (!ec_guard(ec)) return 0; spin_lock_irqsave(&ec->lock, flags); advance_transaction(ec); spin_unlock_irqrestore(&ec->lock, flags); } while (time_before(jiffies, delay)); pr_debug("controller reset, restart transaction\n"); spin_lock_irqsave(&ec->lock, flags); start_transaction(ec); spin_unlock_irqrestore(&ec->lock, flags); } return -ETIME; } static int acpi_ec_transaction_unlocked(struct acpi_ec *ec, struct transaction *t) { unsigned long tmp; int ret = 0; /* start transaction */ spin_lock_irqsave(&ec->lock, tmp); /* Enable GPE for command processing (IBF=0/OBF=1) */ if (!acpi_ec_submit_flushable_request(ec)) { ret = -EINVAL; goto unlock; } ec_dbg_ref(ec, "Increase command"); /* following two actions should be kept atomic */ ec->curr = t; ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command)); start_transaction(ec); spin_unlock_irqrestore(&ec->lock, tmp); ret = ec_poll(ec); spin_lock_irqsave(&ec->lock, tmp); if (t->irq_count == ec_storm_threshold) acpi_ec_clear_storm(ec, EC_FLAGS_COMMAND_STORM); ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command)); ec->curr = NULL; /* Disable GPE for command processing (IBF=0/OBF=1) */ acpi_ec_complete_request(ec); ec_dbg_ref(ec, "Decrease command"); unlock: spin_unlock_irqrestore(&ec->lock, tmp); return ret; } static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t) { int status; u32 glk; if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata)) return -EINVAL; if (t->rdata) memset(t->rdata, 0, t->rlen); mutex_lock(&ec->mutex); if (ec->global_lock) { status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk); if (ACPI_FAILURE(status)) { status = -ENODEV; goto unlock; } } status = acpi_ec_transaction_unlocked(ec, t); if (ec->global_lock) acpi_release_global_lock(glk); unlock: mutex_unlock(&ec->mutex); return status; } static int acpi_ec_burst_enable(struct acpi_ec *ec) { u8 d; struct transaction t = {.command = ACPI_EC_BURST_ENABLE, .wdata = NULL, .rdata = &d, .wlen = 0, .rlen = 1}; return acpi_ec_transaction(ec, &t); } static int acpi_ec_burst_disable(struct acpi_ec *ec) { struct transaction t = {.command = ACPI_EC_BURST_DISABLE, .wdata = NULL, .rdata = NULL, .wlen = 0, .rlen = 0}; return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ? acpi_ec_transaction(ec, &t) : 0; } static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data) { int result; u8 d; struct transaction t = {.command = ACPI_EC_COMMAND_READ, .wdata = &address, .rdata = &d, .wlen = 1, .rlen = 1}; result = acpi_ec_transaction(ec, &t); *data = d; return result; } static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data) { u8 wdata[2] = { address, data }; struct transaction t = {.command = ACPI_EC_COMMAND_WRITE, .wdata = wdata, .rdata = NULL, .wlen = 2, .rlen = 0}; return acpi_ec_transaction(ec, &t); } int ec_read(u8 addr, u8 *val) { int err; u8 temp_data; if (!first_ec) return -ENODEV; err = acpi_ec_read(first_ec, addr, &temp_data); if (!err) { *val = temp_data; return 0; } return err; } EXPORT_SYMBOL(ec_read); int ec_write(u8 addr, u8 val) { int err; if (!first_ec) return -ENODEV; err = acpi_ec_write(first_ec, addr, val); return err; } EXPORT_SYMBOL(ec_write); int ec_transaction(u8 command, const u8 *wdata, unsigned wdata_len, u8 *rdata, unsigned rdata_len) { struct transaction t = {.command = command, .wdata = wdata, .rdata = rdata, .wlen = wdata_len, .rlen = rdata_len}; if (!first_ec) return -ENODEV; return acpi_ec_transaction(first_ec, &t); } EXPORT_SYMBOL(ec_transaction); /* Get the handle to the EC device */ acpi_handle ec_get_handle(void) { if (!first_ec) return NULL; return first_ec->handle; } EXPORT_SYMBOL(ec_get_handle); /* * Process _Q events that might have accumulated in the EC. * Run with locked ec mutex. */ static void acpi_ec_clear(struct acpi_ec *ec) { int i, status; u8 value = 0; for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) { status = acpi_ec_query(ec, &value); if (status || !value) break; } if (unlikely(i == ACPI_EC_CLEAR_MAX)) pr_warn("Warning: Maximum of %d stale EC events cleared\n", i); else pr_info("%d stale EC events cleared\n", i); } static void acpi_ec_start(struct acpi_ec *ec, bool resuming) { unsigned long flags; spin_lock_irqsave(&ec->lock, flags); if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) { ec_dbg_drv("Starting EC"); /* Enable GPE for event processing (SCI_EVT=1) */ if (!resuming) { acpi_ec_submit_request(ec); ec_dbg_ref(ec, "Increase driver"); } ec_log_drv("EC started"); } spin_unlock_irqrestore(&ec->lock, flags); } static bool acpi_ec_stopped(struct acpi_ec *ec) { unsigned long flags; bool flushed; spin_lock_irqsave(&ec->lock, flags); flushed = acpi_ec_flushed(ec); spin_unlock_irqrestore(&ec->lock, flags); return flushed; } static void acpi_ec_stop(struct acpi_ec *ec, bool suspending) { unsigned long flags; spin_lock_irqsave(&ec->lock, flags); if (acpi_ec_started(ec)) { ec_dbg_drv("Stopping EC"); set_bit(EC_FLAGS_STOPPED, &ec->flags); spin_unlock_irqrestore(&ec->lock, flags); wait_event(ec->wait, acpi_ec_stopped(ec)); spin_lock_irqsave(&ec->lock, flags); /* Disable GPE for event processing (SCI_EVT=1) */ if (!suspending) { acpi_ec_complete_request(ec); ec_dbg_ref(ec, "Decrease driver"); } clear_bit(EC_FLAGS_STARTED, &ec->flags); clear_bit(EC_FLAGS_STOPPED, &ec->flags); ec_log_drv("EC stopped"); } spin_unlock_irqrestore(&ec->lock, flags); } void acpi_ec_block_transactions(void) { struct acpi_ec *ec = first_ec; if (!ec) return; mutex_lock(&ec->mutex); /* Prevent transactions from being carried out */ acpi_ec_stop(ec, true); mutex_unlock(&ec->mutex); } void acpi_ec_unblock_transactions(void) { struct acpi_ec *ec = first_ec; if (!ec) return; /* Allow transactions to be carried out again */ acpi_ec_start(ec, true); if (EC_FLAGS_CLEAR_ON_RESUME) acpi_ec_clear(ec); } void acpi_ec_unblock_transactions_early(void) { /* * Allow transactions to happen again (this function is called from * atomic context during wakeup, so we don't need to acquire the mutex). */ if (first_ec) acpi_ec_start(first_ec, true); } /* -------------------------------------------------------------------------- Event Management -------------------------------------------------------------------------- */ static struct acpi_ec_query_handler * acpi_ec_get_query_handler(struct acpi_ec_query_handler *handler) { if (handler) kref_get(&handler->kref); return handler; } static void acpi_ec_query_handler_release(struct kref *kref) { struct acpi_ec_query_handler *handler = container_of(kref, struct acpi_ec_query_handler, kref); kfree(handler); } static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler) { kref_put(&handler->kref, acpi_ec_query_handler_release); } int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit, acpi_handle handle, acpi_ec_query_func func, void *data) { struct acpi_ec_query_handler *handler = kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL); if (!handler) return -ENOMEM; handler->query_bit = query_bit; handler->handle = handle; handler->func = func; handler->data = data; mutex_lock(&ec->mutex); kref_init(&handler->kref); list_add(&handler->node, &ec->list); mutex_unlock(&ec->mutex); return 0; } EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler); void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit) { struct acpi_ec_query_handler *handler, *tmp; LIST_HEAD(free_list); mutex_lock(&ec->mutex); list_for_each_entry_safe(handler, tmp, &ec->list, node) { if (query_bit == handler->query_bit) { list_del_init(&handler->node); list_add(&handler->node, &free_list); } } mutex_unlock(&ec->mutex); list_for_each_entry_safe(handler, tmp, &free_list, node) acpi_ec_put_query_handler(handler); } EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler); static void acpi_ec_run(void *cxt) { struct acpi_ec_query_handler *handler = cxt; if (!handler) return; ec_dbg_evt("Query(0x%02x) started", handler->query_bit); if (handler->func) handler->func(handler->data); else if (handler->handle) acpi_evaluate_object(handler->handle, NULL, NULL, NULL); ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit); acpi_ec_put_query_handler(handler); } static int acpi_ec_query(struct acpi_ec *ec, u8 *data) { u8 value = 0; int result; acpi_status status; struct acpi_ec_query_handler *handler; struct transaction t = {.command = ACPI_EC_COMMAND_QUERY, .wdata = NULL, .rdata = &value, .wlen = 0, .rlen = 1}; /* * Query the EC to find out which _Qxx method we need to evaluate. * Note that successful completion of the query causes the ACPI_EC_SCI * bit to be cleared (and thus clearing the interrupt source). */ result = acpi_ec_transaction(ec, &t); if (result) return result; if (data) *data = value; if (!value) return -ENODATA; mutex_lock(&ec->mutex); list_for_each_entry(handler, &ec->list, node) { if (value == handler->query_bit) { /* have custom handler for this bit */ handler = acpi_ec_get_query_handler(handler); ec_dbg_evt("Query(0x%02x) scheduled", handler->query_bit); status = acpi_os_execute((handler->func) ? OSL_NOTIFY_HANDLER : OSL_GPE_HANDLER, acpi_ec_run, handler); if (ACPI_FAILURE(status)) result = -EBUSY; break; } } mutex_unlock(&ec->mutex); return result; } static void acpi_ec_check_event(struct acpi_ec *ec) { unsigned long flags; if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) { if (ec_guard(ec)) { spin_lock_irqsave(&ec->lock, flags); /* * Take care of the SCI_EVT unless no one else is * taking care of it. */ if (!ec->curr) advance_transaction(ec); spin_unlock_irqrestore(&ec->lock, flags); } } } static void acpi_ec_event_handler(struct work_struct *work) { unsigned long flags; struct acpi_ec *ec = container_of(work, struct acpi_ec, work); ec_dbg_evt("Event started"); spin_lock_irqsave(&ec->lock, flags); while (ec->nr_pending_queries) { spin_unlock_irqrestore(&ec->lock, flags); (void)acpi_ec_query(ec, NULL); spin_lock_irqsave(&ec->lock, flags); ec->nr_pending_queries--; } spin_unlock_irqrestore(&ec->lock, flags); ec_dbg_evt("Event stopped"); acpi_ec_check_event(ec); } static u32 acpi_ec_gpe_handler(acpi_handle gpe_device, u32 gpe_number, void *data) { unsigned long flags; struct acpi_ec *ec = data; spin_lock_irqsave(&ec->lock, flags); advance_transaction(ec); spin_unlock_irqrestore(&ec->lock, flags); return ACPI_INTERRUPT_HANDLED; } /* -------------------------------------------------------------------------- * Address Space Management * -------------------------------------------------------------------------- */ static acpi_status acpi_ec_space_handler(u32 function, acpi_physical_address address, u32 bits, u64 *value64, void *handler_context, void *region_context) { struct acpi_ec *ec = handler_context; int result = 0, i, bytes = bits / 8; u8 *value = (u8 *)value64; if ((address > 0xFF) || !value || !handler_context) return AE_BAD_PARAMETER; if (function != ACPI_READ && function != ACPI_WRITE) return AE_BAD_PARAMETER; if (ec_busy_polling || bits > 8) acpi_ec_burst_enable(ec); for (i = 0; i < bytes; ++i, ++address, ++value) result = (function == ACPI_READ) ? acpi_ec_read(ec, address, value) : acpi_ec_write(ec, address, *value); if (ec_busy_polling || bits > 8) acpi_ec_burst_disable(ec); switch (result) { case -EINVAL: return AE_BAD_PARAMETER; case -ENODEV: return AE_NOT_FOUND; case -ETIME: return AE_TIME; default: return AE_OK; } } /* -------------------------------------------------------------------------- * Driver Interface * -------------------------------------------------------------------------- */ static acpi_status ec_parse_io_ports(struct acpi_resource *resource, void *context); static struct acpi_ec *make_acpi_ec(void) { struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL); if (!ec) return NULL; ec->flags = 1 << EC_FLAGS_QUERY_PENDING; mutex_init(&ec->mutex); init_waitqueue_head(&ec->wait); INIT_LIST_HEAD(&ec->list); spin_lock_init(&ec->lock); INIT_WORK(&ec->work, acpi_ec_event_handler); ec->timestamp = jiffies; return ec; } static acpi_status acpi_ec_register_query_methods(acpi_handle handle, u32 level, void *context, void **return_value) { char node_name[5]; struct acpi_buffer buffer = { sizeof(node_name), node_name }; struct acpi_ec *ec = context; int value = 0; acpi_status status; status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer); if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1) acpi_ec_add_query_handler(ec, value, handle, NULL, NULL); return AE_OK; } static acpi_status ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval) { acpi_status status; unsigned long long tmp = 0; struct acpi_ec *ec = context; /* clear addr values, ec_parse_io_ports depend on it */ ec->command_addr = ec->data_addr = 0; status = acpi_walk_resources(handle, METHOD_NAME__CRS, ec_parse_io_ports, ec); if (ACPI_FAILURE(status)) return status; /* Get GPE bit assignment (EC events). */ /* TODO: Add support for _GPE returning a package */ status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp); if (ACPI_FAILURE(status)) return status; ec->gpe = tmp; /* Use the global lock for all EC transactions? */ tmp = 0; acpi_evaluate_integer(handle, "_GLK", NULL, &tmp); ec->global_lock = tmp; ec->handle = handle; return AE_CTRL_TERMINATE; } static int ec_install_handlers(struct acpi_ec *ec) { acpi_status status; if (test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags)) return 0; status = acpi_install_gpe_raw_handler(NULL, ec->gpe, ACPI_GPE_EDGE_TRIGGERED, &acpi_ec_gpe_handler, ec); if (ACPI_FAILURE(status)) return -ENODEV; acpi_ec_start(ec, false); status = acpi_install_address_space_handler(ec->handle, ACPI_ADR_SPACE_EC, &acpi_ec_space_handler, NULL, ec); if (ACPI_FAILURE(status)) { if (status == AE_NOT_FOUND) { /* * Maybe OS fails in evaluating the _REG object. * The AE_NOT_FOUND error will be ignored and OS * continue to initialize EC. */ pr_err("Fail in evaluating the _REG object" " of EC device. Broken bios is suspected.\n"); } else { acpi_ec_stop(ec, false); acpi_remove_gpe_handler(NULL, ec->gpe, &acpi_ec_gpe_handler); return -ENODEV; } } set_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags); return 0; } static void ec_remove_handlers(struct acpi_ec *ec) { if (!test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags)) return; acpi_ec_stop(ec, false); if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle, ACPI_ADR_SPACE_EC, &acpi_ec_space_handler))) pr_err("failed to remove space handler\n"); if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe, &acpi_ec_gpe_handler))) pr_err("failed to remove gpe handler\n"); clear_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags); } static int acpi_ec_add(struct acpi_device *device) { struct acpi_ec *ec = NULL; int ret; strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME); strcpy(acpi_device_class(device), ACPI_EC_CLASS); /* Check for boot EC */ if (boot_ec && (boot_ec->handle == device->handle || boot_ec->handle == ACPI_ROOT_OBJECT)) { ec = boot_ec; boot_ec = NULL; } else { ec = make_acpi_ec(); if (!ec) return -ENOMEM; } if (ec_parse_device(device->handle, 0, ec, NULL) != AE_CTRL_TERMINATE) { kfree(ec); return -EINVAL; } /* Find and register all query methods */ acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1, acpi_ec_register_query_methods, NULL, ec, NULL); if (!first_ec) first_ec = ec; device->driver_data = ec; ret = !!request_region(ec->data_addr, 1, "EC data"); WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr); ret = !!request_region(ec->command_addr, 1, "EC cmd"); WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr); pr_info("GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n", ec->gpe, ec->command_addr, ec->data_addr); ret = ec_install_handlers(ec); /* Reprobe devices depending on the EC */ acpi_walk_dep_device_list(ec->handle); /* EC is fully operational, allow queries */ clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags); /* Clear stale _Q events if hardware might require that */ if (EC_FLAGS_CLEAR_ON_RESUME) acpi_ec_clear(ec); return ret; } static int acpi_ec_remove(struct acpi_device *device) { struct acpi_ec *ec; struct acpi_ec_query_handler *handler, *tmp; if (!device) return -EINVAL; ec = acpi_driver_data(device); ec_remove_handlers(ec); mutex_lock(&ec->mutex); list_for_each_entry_safe(handler, tmp, &ec->list, node) { list_del(&handler->node); kfree(handler); } mutex_unlock(&ec->mutex); release_region(ec->data_addr, 1); release_region(ec->command_addr, 1); device->driver_data = NULL; if (ec == first_ec) first_ec = NULL; kfree(ec); return 0; } static acpi_status ec_parse_io_ports(struct acpi_resource *resource, void *context) { struct acpi_ec *ec = context; if (resource->type != ACPI_RESOURCE_TYPE_IO) return AE_OK; /* * The first address region returned is the data port, and * the second address region returned is the status/command * port. */ if (ec->data_addr == 0) ec->data_addr = resource->data.io.minimum; else if (ec->command_addr == 0) ec->command_addr = resource->data.io.minimum; else return AE_CTRL_TERMINATE; return AE_OK; } int __init acpi_boot_ec_enable(void) { if (!boot_ec || test_bit(EC_FLAGS_HANDLERS_INSTALLED, &boot_ec->flags)) return 0; if (!ec_install_handlers(boot_ec)) { first_ec = boot_ec; return 0; } return -EFAULT; } static const struct acpi_device_id ec_device_ids[] = { {"PNP0C09", 0}, {"", 0}, }; /* Some BIOS do not survive early DSDT scan, skip it */ static int ec_skip_dsdt_scan(const struct dmi_system_id *id) { EC_FLAGS_SKIP_DSDT_SCAN = 1; return 0; } /* ASUStek often supplies us with broken ECDT, validate it */ static int ec_validate_ecdt(const struct dmi_system_id *id) { EC_FLAGS_VALIDATE_ECDT = 1; return 0; } /* * Acer EC firmware refuses to respond QR_EC when SCI_EVT is not set, for * which case, we complete the QR_EC without issuing it to the firmware. * https://bugzilla.kernel.org/show_bug.cgi?id=86211 */ static int ec_flag_query_handshake(const struct dmi_system_id *id) { pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n"); EC_FLAGS_QUERY_HANDSHAKE = 1; return 0; } /* * On some hardware it is necessary to clear events accumulated by the EC during * sleep. These ECs stop reporting GPEs until they are manually polled, if too * many events are accumulated. (e.g. Samsung Series 5/9 notebooks) * * https://bugzilla.kernel.org/show_bug.cgi?id=44161 * * Ideally, the EC should also be instructed NOT to accumulate events during * sleep (which Windows seems to do somehow), but the interface to control this * behaviour is not known at this time. * * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx, * however it is very likely that other Samsung models are affected. * * On systems which don't accumulate _Q events during sleep, this extra check * should be harmless. */ static int ec_clear_on_resume(const struct dmi_system_id *id) { pr_debug("Detected system needing EC poll on resume.\n"); EC_FLAGS_CLEAR_ON_RESUME = 1; return 0; } static struct dmi_system_id ec_dmi_table[] __initdata = { { ec_skip_dsdt_scan, "Compal JFL92", { DMI_MATCH(DMI_BIOS_VENDOR, "COMPAL"), DMI_MATCH(DMI_BOARD_NAME, "JFL92") }, NULL}, { ec_validate_ecdt, "MSI MS-171F", { DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"), DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL}, { ec_validate_ecdt, "ASUS hardware", { DMI_MATCH(DMI_BIOS_VENDOR, "ASUS") }, NULL}, { ec_validate_ecdt, "ASUS hardware", { DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer Inc.") }, NULL}, { ec_skip_dsdt_scan, "HP Folio 13", { DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"), DMI_MATCH(DMI_PRODUCT_NAME, "HP Folio 13"),}, NULL}, { ec_validate_ecdt, "ASUS hardware", { DMI_MATCH(DMI_SYS_VENDOR, "ASUSTek Computer Inc."), DMI_MATCH(DMI_PRODUCT_NAME, "L4R"),}, NULL}, { ec_clear_on_resume, "Samsung hardware", { DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL}, { ec_flag_query_handshake, "Acer hardware", { DMI_MATCH(DMI_SYS_VENDOR, "Acer"), }, NULL}, {}, }; int __init acpi_ec_ecdt_probe(void) { acpi_status status; struct acpi_ec *saved_ec = NULL; struct acpi_table_ecdt *ecdt_ptr; boot_ec = make_acpi_ec(); if (!boot_ec) return -ENOMEM; /* * Generate a boot ec context */ dmi_check_system(ec_dmi_table); status = acpi_get_table(ACPI_SIG_ECDT, 1, (struct acpi_table_header **)&ecdt_ptr); if (ACPI_SUCCESS(status)) { pr_info("EC description table is found, configuring boot EC\n"); boot_ec->command_addr = ecdt_ptr->control.address; boot_ec->data_addr = ecdt_ptr->data.address; boot_ec->gpe = ecdt_ptr->gpe; boot_ec->handle = ACPI_ROOT_OBJECT; acpi_get_handle(ACPI_ROOT_OBJECT, ecdt_ptr->id, &boot_ec->handle); /* Don't trust ECDT, which comes from ASUSTek */ if (!EC_FLAGS_VALIDATE_ECDT) goto install; saved_ec = kmemdup(boot_ec, sizeof(struct acpi_ec), GFP_KERNEL); if (!saved_ec) return -ENOMEM; /* fall through */ } if (EC_FLAGS_SKIP_DSDT_SCAN) { kfree(saved_ec); return -ENODEV; } /* This workaround is needed only on some broken machines, * which require early EC, but fail to provide ECDT */ pr_debug("Look up EC in DSDT\n"); status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device, boot_ec, NULL); /* Check that acpi_get_devices actually find something */ if (ACPI_FAILURE(status) || !boot_ec->handle) goto error; if (saved_ec) { /* try to find good ECDT from ASUSTek */ if (saved_ec->command_addr != boot_ec->command_addr || saved_ec->data_addr != boot_ec->data_addr || saved_ec->gpe != boot_ec->gpe || saved_ec->handle != boot_ec->handle) pr_info("ASUSTek keeps feeding us with broken " "ECDT tables, which are very hard to workaround. " "Trying to use DSDT EC info instead. Please send " "output of acpidump to linux-acpi@vger.kernel.org\n"); kfree(saved_ec); saved_ec = NULL; } else { /* We really need to limit this workaround, the only ASUS, * which needs it, has fake EC._INI method, so use it as flag. * Keep boot_ec struct as it will be needed soon. */ if (!dmi_name_in_vendors("ASUS") || !acpi_has_method(boot_ec->handle, "_INI")) return -ENODEV; } install: if (!ec_install_handlers(boot_ec)) { first_ec = boot_ec; return 0; } error: kfree(boot_ec); kfree(saved_ec); boot_ec = NULL; return -ENODEV; } static int param_set_event_clearing(const char *val, struct kernel_param *kp) { int result = 0; if (!strncmp(val, "status", sizeof("status") - 1)) { ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS; pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n"); } else if (!strncmp(val, "query", sizeof("query") - 1)) { ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY; pr_info("Assuming SCI_EVT clearing on QR_EC writes\n"); } else if (!strncmp(val, "event", sizeof("event") - 1)) { ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT; pr_info("Assuming SCI_EVT clearing on event reads\n"); } else result = -EINVAL; return result; } static int param_get_event_clearing(char *buffer, struct kernel_param *kp) { switch (ec_event_clearing) { case ACPI_EC_EVT_TIMING_STATUS: return sprintf(buffer, "status"); case ACPI_EC_EVT_TIMING_QUERY: return sprintf(buffer, "query"); case ACPI_EC_EVT_TIMING_EVENT: return sprintf(buffer, "event"); default: return sprintf(buffer, "invalid"); } return 0; } module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing, NULL, 0644); MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing"); static struct acpi_driver acpi_ec_driver = { .name = "ec", .class = ACPI_EC_CLASS, .ids = ec_device_ids, .ops = { .add = acpi_ec_add, .remove = acpi_ec_remove, }, }; int __init acpi_ec_init(void) { int result = 0; /* Now register the driver for the EC */ result = acpi_bus_register_driver(&acpi_ec_driver); if (result < 0) return -ENODEV; return result; } /* EC driver currently not unloadable */ #if 0 static void __exit acpi_ec_exit(void) { acpi_bus_unregister_driver(&acpi_ec_driver); } #endif /* 0 */