diff options
Diffstat (limited to 'drivers/acpi/ec.c')
| -rw-r--r-- | drivers/acpi/ec.c | 1459 |
1 files changed, 1459 insertions, 0 deletions
diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c new file mode 100644 index 000000000..5e8fed448 --- /dev/null +++ b/drivers/acpi/ec.c @@ -0,0 +1,1459 @@ +/* + * ec.c - ACPI Embedded Controller Driver (v3) + * + * Copyright (C) 2001-2015 Intel Corporation + * Author: 2014, 2015 Lv Zheng <lv.zheng@intel.com> + * 2006, 2007 Alexey Starikovskiy <alexey.y.starikovskiy@intel.com> + * 2006 Denis Sadykov <denis.m.sadykov@intel.com> + * 2004 Luming Yu <luming.yu@intel.com> + * 2001, 2002 Andy Grover <andrew.grover@intel.com> + * 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com> + * Copyright (C) 2008 Alexey Starikovskiy <astarikovskiy@suse.de> + * + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + * + * 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 <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/types.h> +#include <linux/delay.h> +#include <linux/interrupt.h> +#include <linux/list.h> +#include <linux/spinlock.h> +#include <linux/slab.h> +#include <linux/acpi.h> +#include <linux/dmi.h> +#include <asm/io.h> + +#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 */ + +/* 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_MSI_UDELAY 550 /* Wait 550us for MSI EC */ +#define ACPI_EC_UDELAY_POLL 1000 /* 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_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"); + +/* + * 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; + unsigned long timestamp; +}; + +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_MSI; /* Out-of-spec MSI controller */ +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->curr->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->curr->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->curr->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_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_req("Event started"); + schedule_work(&ec->work); + } +} + +static void acpi_ec_complete_query(struct acpi_ec *ec) +{ + if (ec->curr->command == ACPI_EC_COMMAND_QUERY) { + clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags); + ec_dbg_req("Event stopped"); + } +} + +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 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; + 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) { + t->flags |= ACPI_EC_COMMAND_COMPLETE; + if (t->command == ACPI_EC_COMMAND_QUERY) + ec_dbg_req("Command(%s) hardware completion", + acpi_ec_cmd_string(t->command)); + wakeup = true; + } + } else + goto err; + } else if (t->wlen == t->wi && + (status & ACPI_EC_FLAG_IBF) == 0) { + t->flags |= 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)) { + t->flags |= ACPI_EC_COMMAND_POLL; + acpi_ec_complete_query(ec); + t->rdata[t->ri++] = 0x00; + t->flags |= ACPI_EC_COMMAND_COMPLETE; + ec_dbg_req("Command(%s) software completion", + acpi_ec_cmd_string(t->command)); + wakeup = true; + } else if ((status & ACPI_EC_FLAG_IBF) == 0) { + acpi_ec_write_cmd(ec, t->command); + t->flags |= ACPI_EC_COMMAND_POLL; + acpi_ec_complete_query(ec); + } 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; + ec->curr->timestamp = jiffies; + advance_transaction(ec); +} + +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); + unsigned long usecs = ACPI_EC_UDELAY_POLL; + do { + /* don't sleep with disabled interrupts */ + if (EC_FLAGS_MSI || irqs_disabled()) { + usecs = ACPI_EC_MSI_UDELAY; + udelay(usecs); + if (ec_transaction_completed(ec)) + return 0; + } else { + if (wait_event_timeout(ec->wait, + ec_transaction_completed(ec), + usecs_to_jiffies(usecs))) + return 0; + } + spin_lock_irqsave(&ec->lock, flags); + if (time_after(jiffies, + ec->curr->timestamp + + usecs_to_jiffies(usecs))) + 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; + + if (EC_FLAGS_MSI) + udelay(ACPI_EC_MSI_UDELAY); + /* 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 (test_bit(EC_FLAGS_COMMAND_STORM, &ec->flags)) + msleep(1); + 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_gpe_poller(struct work_struct *work) +{ + struct acpi_ec *ec = container_of(work, struct acpi_ec, work); + + acpi_ec_query(ec, NULL); +} + +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_FLAGS_MSI || 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_FLAGS_MSI || 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_gpe_poller); + 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; +} + +/* MSI EC needs special treatment, enable it */ +static int ec_flag_msi(const struct dmi_system_id *id) +{ + pr_debug("Detected MSI hardware, enabling workarounds.\n"); + EC_FLAGS_MSI = 1; + EC_FLAGS_VALIDATE_ECDT = 1; + return 0; +} + +/* + * Clevo M720 notebook actually works ok with IRQ mode, if we lifted + * the GPE storm threshold back to 20 + */ +static int ec_enlarge_storm_threshold(const struct dmi_system_id *id) +{ + pr_debug("Setting the EC GPE storm threshold to 20\n"); + ec_storm_threshold = 20; + 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_flag_msi, "MSI hardware", { + DMI_MATCH(DMI_BIOS_VENDOR, "Micro-Star")}, NULL}, + { + ec_flag_msi, "MSI hardware", { + DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star")}, NULL}, + { + ec_flag_msi, "MSI hardware", { + DMI_MATCH(DMI_CHASSIS_VENDOR, "MICRO-Star")}, NULL}, + { + ec_flag_msi, "MSI hardware", { + DMI_MATCH(DMI_CHASSIS_VENDOR, "MICRO-STAR")}, NULL}, + { + ec_flag_msi, "Quanta hardware", { + DMI_MATCH(DMI_SYS_VENDOR, "Quanta"), + DMI_MATCH(DMI_PRODUCT_NAME, "TW8/SW8/DW8"),}, NULL}, + { + ec_flag_msi, "Quanta hardware", { + DMI_MATCH(DMI_SYS_VENDOR, "Quanta"), + DMI_MATCH(DMI_PRODUCT_NAME, "TW9/SW9"),}, NULL}, + { + ec_flag_msi, "Clevo W350etq", { + DMI_MATCH(DMI_SYS_VENDOR, "CLEVO CO."), + DMI_MATCH(DMI_PRODUCT_NAME, "W35_37ET"),}, 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_enlarge_storm_threshold, "CLEVO hardware", { + DMI_MATCH(DMI_SYS_VENDOR, "CLEVO Co."), + DMI_MATCH(DMI_PRODUCT_NAME, "M720T/M730T"),}, 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 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 */ |