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linux/drivers/acpi/ec.c
Muhammad Qasim Abdul Majeed f098bb555f ACPI: EC: Use strscpy() instead of strcpy() 
Replace strcpy() with strscpy() in the ACPI EC driver.

strcpy() has been deprecated because it is generally unsafe, so it
is better to eliminate it from the kernel source.

Link: https://github.com/KSPP/linux/issues/88
Signed-off-by: Muhammad Qasim Abdul Majeed <qasim.majeed20@gmail.com>
Link: https://patch.msgid.link/20240915183822.34588-2-qasim.majeed20@gmail.com
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2024-11-05 21:35:35 +01:00

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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>
*/
/* 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/suspend.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"
/* 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 */
#define ACPI_EC_MAX_QUERIES 16 /* Maximum number of parallel queries */
enum {
EC_FLAGS_QUERY_ENABLED, /* Query is enabled */
EC_FLAGS_EVENT_HANDLER_INSTALLED, /* Event handler installed */
EC_FLAGS_EC_HANDLER_INSTALLED, /* OpReg handler installed */
EC_FLAGS_EC_REG_CALLED, /* OpReg ACPI _REG method called */
EC_FLAGS_QUERY_METHODS_INSTALLED, /* _Qxx handlers installed */
EC_FLAGS_STARTED, /* Driver is started */
EC_FLAGS_STOPPED, /* Driver is stopped */
EC_FLAGS_EVENTS_MASKED, /* Events masked */
};
#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 unsigned int ec_max_queries __read_mostly = ACPI_EC_MAX_QUERIES;
module_param(ec_max_queries, uint, 0644);
MODULE_PARM_DESC(ec_max_queries, "Maximum parallel _Qxx evaluations");
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_QUERY;
/*
* 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");
static bool ec_freeze_events __read_mostly;
module_param(ec_freeze_events, bool, 0644);
MODULE_PARM_DESC(ec_freeze_events, "Disabling event handling during suspend/resume");
static bool ec_no_wakeup __read_mostly;
module_param(ec_no_wakeup, bool, 0644);
MODULE_PARM_DESC(ec_no_wakeup, "Do not wake up from suspend-to-idle");
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;
};
struct acpi_ec_query {
struct transaction transaction;
struct work_struct work;
struct acpi_ec_query_handler *handler;
struct acpi_ec *ec;
};
static int acpi_ec_submit_query(struct acpi_ec *ec);
static void advance_transaction(struct acpi_ec *ec, bool interrupt);
static void acpi_ec_event_handler(struct work_struct *work);
struct acpi_ec *first_ec;
EXPORT_SYMBOL(first_ec);
static struct acpi_ec *boot_ec;
static bool boot_ec_is_ecdt;
static struct workqueue_struct *ec_wq;
static struct workqueue_struct *ec_query_wq;
static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
static int EC_FLAGS_TRUST_DSDT_GPE; /* Needs DSDT GPE as correction setting */
static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
/* --------------------------------------------------------------------------
* 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_event_enabled(struct acpi_ec *ec)
{
/*
* There is an OSPM early stage logic. During the early stages
* (boot/resume), OSPMs shouldn't enable the event handling, only
* the EC transactions are allowed to be performed.
*/
if (!test_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
return false;
/*
* However, disabling the event handling is experimental for late
* stage (suspend), and is controlled by the boot parameter of
* "ec_freeze_events":
* 1. true: The EC event handling is disabled before entering
* the noirq stage.
* 2. false: The EC event handling is automatically disabled as
* soon as the EC driver is stopped.
*/
if (ec_freeze_events)
return acpi_ec_started(ec);
else
return test_bit(EC_FLAGS_STARTED, &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;
}
#if defined(DEBUG) || defined(CONFIG_DYNAMIC_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_gpe_status_set(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);
}
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_gpe_status_set(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, false);
}
}
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);
}
}
/* --------------------------------------------------------------------------
* Transaction Management
* -------------------------------------------------------------------------- */
static void acpi_ec_submit_request(struct acpi_ec *ec)
{
ec->reference_count++;
if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
ec->gpe >= 0 && 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 (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
ec->gpe >= 0 && 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_mask_events(struct acpi_ec *ec)
{
if (!test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
if (ec->gpe >= 0)
acpi_ec_disable_gpe(ec, false);
else
disable_irq_nosync(ec->irq);
ec_dbg_drv("Polling enabled");
set_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
}
}
static void acpi_ec_unmask_events(struct acpi_ec *ec)
{
if (test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
clear_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
if (ec->gpe >= 0)
acpi_ec_enable_gpe(ec, false);
else
enable_irq(ec->irq);
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_event(struct acpi_ec *ec)
{
/*
* It is safe to mask the events here, because acpi_ec_close_event()
* will run at least once after this.
*/
acpi_ec_mask_events(ec);
if (!acpi_ec_event_enabled(ec))
return;
if (ec->event_state != EC_EVENT_READY)
return;
ec_dbg_evt("Command(%s) submitted/blocked",
acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
ec->event_state = EC_EVENT_IN_PROGRESS;
/*
* If events_to_process is greater than 0 at this point, the while ()
* loop in acpi_ec_event_handler() is still running and incrementing
* events_to_process will cause it to invoke acpi_ec_submit_query() once
* more, so it is not necessary to queue up the event work to start the
* same loop again.
*/
if (ec->events_to_process++ > 0)
return;
ec->events_in_progress++;
queue_work(ec_wq, &ec->work);
}
static void acpi_ec_complete_event(struct acpi_ec *ec)
{
if (ec->event_state == EC_EVENT_IN_PROGRESS)
ec->event_state = EC_EVENT_COMPLETE;
}
static void acpi_ec_close_event(struct acpi_ec *ec)
{
if (ec->event_state != EC_EVENT_READY)
ec_dbg_evt("Command(%s) unblocked",
acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
ec->event_state = EC_EVENT_READY;
acpi_ec_unmask_events(ec);
}
static inline void __acpi_ec_enable_event(struct acpi_ec *ec)
{
if (!test_and_set_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
ec_log_drv("event unblocked");
/*
* Unconditionally invoke this once after enabling the event
* handling mechanism to detect the pending events.
*/
advance_transaction(ec, false);
}
static inline void __acpi_ec_disable_event(struct acpi_ec *ec)
{
if (test_and_clear_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
ec_log_drv("event blocked");
}
/*
* 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;
for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
if (acpi_ec_submit_query(ec))
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_enable_event(struct acpi_ec *ec)
{
unsigned long flags;
spin_lock_irqsave(&ec->lock, flags);
if (acpi_ec_started(ec))
__acpi_ec_enable_event(ec);
spin_unlock_irqrestore(&ec->lock, flags);
/* Drain additional events if hardware requires that */
if (EC_FLAGS_CLEAR_ON_RESUME)
acpi_ec_clear(ec);
}
#ifdef CONFIG_PM_SLEEP
static void __acpi_ec_flush_work(void)
{
flush_workqueue(ec_wq); /* flush ec->work */
flush_workqueue(ec_query_wq); /* flush queries */
}
static void acpi_ec_disable_event(struct acpi_ec *ec)
{
unsigned long flags;
spin_lock_irqsave(&ec->lock, flags);
__acpi_ec_disable_event(ec);
spin_unlock_irqrestore(&ec->lock, flags);
/*
* When ec_freeze_events is true, we need to flush events in
* the proper position before entering the noirq stage.
*/
__acpi_ec_flush_work();
}
void acpi_ec_flush_work(void)
{
/* Without ec_wq there is nothing to flush. */
if (!ec_wq)
return;
__acpi_ec_flush_work();
}
#endif /* CONFIG_PM_SLEEP */
static bool acpi_ec_guard_event(struct acpi_ec *ec)
{
unsigned long flags;
bool guarded;
spin_lock_irqsave(&ec->lock, flags);
/*
* If firmware SCI_EVT clearing timing is "event", we actually
* don't know when the SCI_EVT will be cleared by firmware after
* evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
* acceptable period.
*
* The guarding period is applicable if the event state is not
* EC_EVENT_READY, but otherwise if the current transaction is of the
* ACPI_EC_COMMAND_QUERY type, the guarding should have elapsed already
* and it should not be applied to let the transaction transition into
* the ACPI_EC_COMMAND_POLL state immediately.
*/
guarded = ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
ec->event_state != EC_EVENT_READY &&
(!ec->curr || ec->curr->command != ACPI_EC_COMMAND_QUERY);
spin_unlock_irqrestore(&ec->lock, flags);
return guarded;
}
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)
return;
switch (ec_event_clearing) {
case ACPI_EC_EVT_TIMING_STATUS:
if (flag == ACPI_EC_COMMAND_POLL)
acpi_ec_close_event(ec);
return;
case ACPI_EC_EVT_TIMING_QUERY:
if (flag == ACPI_EC_COMMAND_COMPLETE)
acpi_ec_close_event(ec);
return;
case ACPI_EC_EVT_TIMING_EVENT:
if (flag == ACPI_EC_COMMAND_COMPLETE)
acpi_ec_complete_event(ec);
}
}
static void acpi_ec_spurious_interrupt(struct acpi_ec *ec, struct transaction *t)
{
if (t->irq_count < ec_storm_threshold)
++t->irq_count;
/* Trigger if the threshold is 0 too. */
if (t->irq_count == ec_storm_threshold)
acpi_ec_mask_events(ec);
}
static void advance_transaction(struct acpi_ec *ec, bool interrupt)
{
struct transaction *t = ec->curr;
bool wakeup = false;
u8 status;
ec_dbg_stm("%s (%d)", interrupt ? "IRQ" : "TASK", smp_processor_id());
status = acpi_ec_read_status(ec);
/*
* 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 &&
ec->event_state == EC_EVENT_COMPLETE)
acpi_ec_close_event(ec);
if (!t)
goto out;
}
if (t->flags & ACPI_EC_COMMAND_POLL) {
if (t->wlen > t->wi) {
if (!(status & ACPI_EC_FLAG_IBF))
acpi_ec_write_data(ec, t->wdata[t->wi++]);
else if (interrupt && !(status & ACPI_EC_FLAG_SCI))
acpi_ec_spurious_interrupt(ec, t);
} else if (t->rlen > t->ri) {
if (status & ACPI_EC_FLAG_OBF) {
t->rdata[t->ri++] = acpi_ec_read_data(ec);
if (t->rlen == t->ri) {
ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
wakeup = true;
if (t->command == ACPI_EC_COMMAND_QUERY)
ec_dbg_evt("Command(%s) completed by hardware",
acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
}
} else if (interrupt && !(status & ACPI_EC_FLAG_SCI)) {
acpi_ec_spurious_interrupt(ec, t);
}
} else if (t->wlen == t->wi && !(status & ACPI_EC_FLAG_IBF)) {
ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
wakeup = true;
}
} else if (!(status & ACPI_EC_FLAG_IBF)) {
acpi_ec_write_cmd(ec, t->command);
ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
}
out:
if (status & ACPI_EC_FLAG_SCI)
acpi_ec_submit_event(ec);
if (wakeup && 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;
/* Ensure guarding period before polling EC status */
do {
if (ec->busy_polling) {
/* Perform busy polling */
if (ec_transaction_completed(ec))
return 0;
udelay(jiffies_to_usecs(guard));
} else {
/*
* Perform wait polling
* 1. Wait the transaction to be completed by the
* GPE handler after the transaction enters
* ACPI_EC_COMMAND_POLL state.
* 2. A special guarding logic is also required
* for event clearing mode "event" before the
* transaction enters ACPI_EC_COMMAND_POLL
* state.
*/
if (!ec_transaction_polled(ec) &&
!acpi_ec_guard_event(ec))
break;
if (wait_event_timeout(ec->wait,
ec_transaction_completed(ec),
guard))
return 0;
}
} 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, false);
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 (t->rdata)
memset(t->rdata, 0, t->rlen);
/* 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_unmask_events(ec);
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;
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_unlocked(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_unlocked(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_read_unlocked(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_unlocked(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);
}
static int acpi_ec_write_unlocked(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_unlocked(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)
{
if (!first_ec)
return -ENODEV;
return acpi_ec_write(first_ec, addr, val);
}
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);
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");
} else if (!ec_freeze_events)
__acpi_ec_disable_event(ec);
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);
}
static void acpi_ec_enter_noirq(struct acpi_ec *ec)
{
unsigned long flags;
spin_lock_irqsave(&ec->lock, flags);
ec->busy_polling = true;
ec->polling_guard = 0;
ec_log_drv("interrupt blocked");
spin_unlock_irqrestore(&ec->lock, flags);
}
static void acpi_ec_leave_noirq(struct acpi_ec *ec)
{
unsigned long flags;
spin_lock_irqsave(&ec->lock, flags);
ec->busy_polling = ec_busy_polling;
ec->polling_guard = ec_polling_guard;
ec_log_drv("interrupt unblocked");
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)
{
/*
* 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_by_value(struct acpi_ec *ec, u8 value)
{
struct acpi_ec_query_handler *handler;
mutex_lock(&ec->mutex);
list_for_each_entry(handler, &ec->list, node) {
if (value == handler->query_bit) {
kref_get(&handler->kref);
mutex_unlock(&ec->mutex);
return handler;
}
}
mutex_unlock(&ec->mutex);
return NULL;
}
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;
if (!handle && !func)
return -EINVAL;
handler = kzalloc(sizeof(*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);
static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
bool remove_all, 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) {
/*
* When remove_all is false, only remove custom query handlers
* which have handler->func set. This is done to preserve query
* handlers discovered thru ACPI, as they should continue handling
* EC queries.
*/
if (remove_all || (handler->func && handler->query_bit == 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);
}
void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
{
acpi_ec_remove_query_handlers(ec, false, query_bit);
flush_workqueue(ec_query_wq);
}
EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
static void acpi_ec_event_processor(struct work_struct *work)
{
struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
struct acpi_ec_query_handler *handler = q->handler;
struct acpi_ec *ec = q->ec;
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);
spin_lock_irq(&ec->lock);
ec->queries_in_progress--;
spin_unlock_irq(&ec->lock);
acpi_ec_put_query_handler(handler);
kfree(q);
}
static struct acpi_ec_query *acpi_ec_create_query(struct acpi_ec *ec, u8 *pval)
{
struct acpi_ec_query *q;
struct transaction *t;
q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
if (!q)
return NULL;
INIT_WORK(&q->work, acpi_ec_event_processor);
t = &q->transaction;
t->command = ACPI_EC_COMMAND_QUERY;
t->rdata = pval;
t->rlen = 1;
q->ec = ec;
return q;
}
static int acpi_ec_submit_query(struct acpi_ec *ec)
{
struct acpi_ec_query *q;
u8 value = 0;
int result;
q = acpi_ec_create_query(ec, &value);
if (!q)
return -ENOMEM;
/*
* 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, &q->transaction);
if (result)
goto err_exit;
if (!value) {
result = -ENODATA;
goto err_exit;
}
q->handler = acpi_ec_get_query_handler_by_value(ec, value);
if (!q->handler) {
result = -ENODATA;
goto err_exit;
}
/*
* It is reported that _Qxx are evaluated in a parallel way on Windows:
* https://bugzilla.kernel.org/show_bug.cgi?id=94411
*
* Put this log entry before queue_work() to make it appear in the log
* before any other messages emitted during workqueue handling.
*/
ec_dbg_evt("Query(0x%02x) scheduled", value);
spin_lock_irq(&ec->lock);
ec->queries_in_progress++;
queue_work(ec_query_wq, &q->work);
spin_unlock_irq(&ec->lock);
return 0;
err_exit:
kfree(q);
return result;
}
static void acpi_ec_event_handler(struct work_struct *work)
{
struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
ec_dbg_evt("Event started");
spin_lock_irq(&ec->lock);
while (ec->events_to_process) {
spin_unlock_irq(&ec->lock);
acpi_ec_submit_query(ec);
spin_lock_irq(&ec->lock);
ec->events_to_process--;
}
/*
* Before exit, make sure that the it will be possible to queue up the
* event handling work again regardless of whether or not the query
* queued up above is processed successfully.
*/
if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
bool guard_timeout;
acpi_ec_complete_event(ec);
ec_dbg_evt("Event stopped");
spin_unlock_irq(&ec->lock);
guard_timeout = !!ec_guard(ec);
spin_lock_irq(&ec->lock);
/* Take care of SCI_EVT unless someone else is doing that. */
if (guard_timeout && !ec->curr)
advance_transaction(ec, false);
} else {
acpi_ec_close_event(ec);
ec_dbg_evt("Event stopped");
}
ec->events_in_progress--;
spin_unlock_irq(&ec->lock);
}
static void clear_gpe_and_advance_transaction(struct acpi_ec *ec, bool interrupt)
{
/*
* Clear GPE_STS upfront to allow subsequent hardware GPE_STS 0->1
* changes to always trigger a GPE interrupt.
*
* GPE STS is a W1C register, which means:
*
* 1. Software can clear it without worrying about clearing the 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.
*/
if (ec->gpe >= 0 && acpi_ec_gpe_status_set(ec))
acpi_clear_gpe(NULL, ec->gpe);
advance_transaction(ec, true);
}
static void acpi_ec_handle_interrupt(struct acpi_ec *ec)
{
unsigned long flags;
spin_lock_irqsave(&ec->lock, flags);
clear_gpe_and_advance_transaction(ec, true);
spin_unlock_irqrestore(&ec->lock, flags);
}
static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
u32 gpe_number, void *data)
{
acpi_ec_handle_interrupt(data);
return ACPI_INTERRUPT_HANDLED;
}
static irqreturn_t acpi_ec_irq_handler(int irq, void *data)
{
acpi_ec_handle_interrupt(data);
return IRQ_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;
u32 glk;
if ((address > 0xFF) || !value || !handler_context)
return AE_BAD_PARAMETER;
if (function != ACPI_READ && function != ACPI_WRITE)
return AE_BAD_PARAMETER;
mutex_lock(&ec->mutex);
if (ec->global_lock) {
acpi_status status;
status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
if (ACPI_FAILURE(status)) {
result = -ENODEV;
goto unlock;
}
}
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_unlocked(ec, address, value) :
acpi_ec_write_unlocked(ec, address, *value);
if (result < 0)
break;
}
if (ec->busy_polling || bits > 8)
acpi_ec_burst_disable(ec);
if (ec->global_lock)
acpi_release_global_lock(glk);
unlock:
mutex_unlock(&ec->mutex);
switch (result) {
case -EINVAL:
return AE_BAD_PARAMETER;
case -ENODEV:
return AE_NOT_FOUND;
case -ETIME:
return AE_TIME;
case 0:
return AE_OK;
default:
return AE_ERROR;
}
}
/* --------------------------------------------------------------------------
* Driver Interface
* -------------------------------------------------------------------------- */
static acpi_status
ec_parse_io_ports(struct acpi_resource *resource, void *context);
static void acpi_ec_free(struct acpi_ec *ec)
{
if (first_ec == ec)
first_ec = NULL;
if (boot_ec == ec)
boot_ec = NULL;
kfree(ec);
}
static struct acpi_ec *acpi_ec_alloc(void)
{
struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
if (!ec)
return NULL;
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;
ec->busy_polling = true;
ec->polling_guard = 0;
ec->gpe = -1;
ec->irq = -1;
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;
if (ec->data_addr == 0 || ec->command_addr == 0)
return AE_OK;
/* Get GPE bit assignment (EC events). */
/* TODO: Add support for _GPE returning a package */
status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
if (ACPI_SUCCESS(status))
ec->gpe = tmp;
/*
* Errors are non-fatal, allowing for ACPI Reduced Hardware
* platforms which use GpioInt instead of GPE.
*/
/* 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 bool install_gpe_event_handler(struct acpi_ec *ec)
{
acpi_status status;
status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
ACPI_GPE_EDGE_TRIGGERED,
&acpi_ec_gpe_handler, ec);
if (ACPI_FAILURE(status))
return false;
if (test_bit(EC_FLAGS_STARTED, &ec->flags) && ec->reference_count >= 1)
acpi_ec_enable_gpe(ec, true);
return true;
}
static bool install_gpio_irq_event_handler(struct acpi_ec *ec)
{
return request_threaded_irq(ec->irq, NULL, acpi_ec_irq_handler,
IRQF_SHARED | IRQF_ONESHOT, "ACPI EC", ec) >= 0;
}
/**
* ec_install_handlers - Install service callbacks and register query methods.
* @ec: Target EC.
* @device: ACPI device object corresponding to @ec.
* @call_reg: If _REG should be called to notify OpRegion availability
*
* Install a handler for the EC address space type unless it has been installed
* already. If @device is not NULL, also look for EC query methods in the
* namespace and register them, and install an event (either GPE or GPIO IRQ)
* handler for the EC, if possible.
*
* Return:
* -ENODEV if the address space handler cannot be installed, which means
* "unable to handle transactions",
* -EPROBE_DEFER if GPIO IRQ acquisition needs to be deferred,
* or 0 (success) otherwise.
*/
static int ec_install_handlers(struct acpi_ec *ec, struct acpi_device *device,
bool call_reg)
{
acpi_status status;
acpi_ec_start(ec, false);
if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
acpi_handle scope_handle = ec == first_ec ? ACPI_ROOT_OBJECT : ec->handle;
acpi_ec_enter_noirq(ec);
status = acpi_install_address_space_handler_no_reg(scope_handle,
ACPI_ADR_SPACE_EC,
&acpi_ec_space_handler,
NULL, ec);
if (ACPI_FAILURE(status)) {
acpi_ec_stop(ec, false);
return -ENODEV;
}
set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
}
if (call_reg && !test_bit(EC_FLAGS_EC_REG_CALLED, &ec->flags)) {
acpi_execute_reg_methods(ec->handle, ACPI_UINT32_MAX, ACPI_ADR_SPACE_EC);
set_bit(EC_FLAGS_EC_REG_CALLED, &ec->flags);
}
if (!device)
return 0;
if (ec->gpe < 0) {
/* ACPI reduced hardware platforms use a GpioInt from _CRS. */
int irq = acpi_dev_gpio_irq_get(device, 0);
/*
* Bail out right away for deferred probing or complete the
* initialization regardless of any other errors.
*/
if (irq == -EPROBE_DEFER)
return -EPROBE_DEFER;
else if (irq >= 0)
ec->irq = irq;
}
if (!test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
/* Find and register all query methods */
acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
acpi_ec_register_query_methods,
NULL, ec, NULL);
set_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
}
if (!test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
bool ready = false;
if (ec->gpe >= 0)
ready = install_gpe_event_handler(ec);
else if (ec->irq >= 0)
ready = install_gpio_irq_event_handler(ec);
if (ready) {
set_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
acpi_ec_leave_noirq(ec);
}
/*
* Failures to install an event handler are not fatal, because
* the EC can be polled for events.
*/
}
/* EC is fully operational, allow queries */
acpi_ec_enable_event(ec);
return 0;
}
static void ec_remove_handlers(struct acpi_ec *ec)
{
acpi_handle scope_handle = ec == first_ec ? ACPI_ROOT_OBJECT : ec->handle;
if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
if (ACPI_FAILURE(acpi_remove_address_space_handler(
scope_handle,
ACPI_ADR_SPACE_EC,
&acpi_ec_space_handler)))
pr_err("failed to remove space handler\n");
clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
}
/*
* Stops handling the EC transactions after removing the operation
* region handler. This is required because _REG(DISCONNECT)
* invoked during the removal can result in new EC transactions.
*
* Flushes the EC requests and thus disables the GPE before
* removing the GPE handler. This is required by the current ACPICA
* GPE core. ACPICA GPE core will automatically disable a GPE when
* it is indicated but there is no way to handle it. So the drivers
* must disable the GPEs prior to removing the GPE handlers.
*/
acpi_ec_stop(ec, false);
if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
if (ec->gpe >= 0 &&
ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
&acpi_ec_gpe_handler)))
pr_err("failed to remove gpe handler\n");
if (ec->irq >= 0)
free_irq(ec->irq, ec);
clear_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
}
if (test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
acpi_ec_remove_query_handlers(ec, true, 0);
clear_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
}
}
static int acpi_ec_setup(struct acpi_ec *ec, struct acpi_device *device, bool call_reg)
{
int ret;
/* First EC capable of handling transactions */
if (!first_ec)
first_ec = ec;
ret = ec_install_handlers(ec, device, call_reg);
if (ret) {
if (ec == first_ec)
first_ec = NULL;
return ret;
}
pr_info("EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n", ec->command_addr,
ec->data_addr);
if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
if (ec->gpe >= 0)
pr_info("GPE=0x%x\n", ec->gpe);
else
pr_info("IRQ=%d\n", ec->irq);
}
return ret;
}
static int acpi_ec_add(struct acpi_device *device)
{
struct acpi_ec *ec;
int ret;
strscpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
strscpy(acpi_device_class(device), ACPI_EC_CLASS);
if (boot_ec && (boot_ec->handle == device->handle ||
!strcmp(acpi_device_hid(device), ACPI_ECDT_HID))) {
/* Fast path: this device corresponds to the boot EC. */
ec = boot_ec;
} else {
acpi_status status;
ec = acpi_ec_alloc();
if (!ec)
return -ENOMEM;
status = ec_parse_device(device->handle, 0, ec, NULL);
if (status != AE_CTRL_TERMINATE) {
ret = -EINVAL;
goto err;
}
if (boot_ec && ec->command_addr == boot_ec->command_addr &&
ec->data_addr == boot_ec->data_addr) {
/*
* Trust PNP0C09 namespace location rather than ECDT ID.
* But trust ECDT GPE rather than _GPE because of ASUS
* quirks. So do not change boot_ec->gpe to ec->gpe,
* except when the TRUST_DSDT_GPE quirk is set.
*/
boot_ec->handle = ec->handle;
if (EC_FLAGS_TRUST_DSDT_GPE)
boot_ec->gpe = ec->gpe;
acpi_handle_debug(ec->handle, "duplicated.\n");
acpi_ec_free(ec);
ec = boot_ec;
}
}
ret = acpi_ec_setup(ec, device, true);
if (ret)
goto err;
if (ec == boot_ec)
acpi_handle_info(boot_ec->handle,
"Boot %s EC initialization complete\n",
boot_ec_is_ecdt ? "ECDT" : "DSDT");
acpi_handle_info(ec->handle,
"EC: Used to handle transactions and events\n");
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);
/* Reprobe devices depending on the EC */
acpi_dev_clear_dependencies(device);
acpi_handle_debug(ec->handle, "enumerated.\n");
return 0;
err:
if (ec != boot_ec)
acpi_ec_free(ec);
return ret;
}
static void acpi_ec_remove(struct acpi_device *device)
{
struct acpi_ec *ec;
if (!device)
return;
ec = acpi_driver_data(device);
release_region(ec->data_addr, 1);
release_region(ec->command_addr, 1);
device->driver_data = NULL;
if (ec != boot_ec) {
ec_remove_handlers(ec);
acpi_ec_free(ec);
}
}
void acpi_ec_register_opregions(struct acpi_device *adev)
{
if (first_ec && first_ec->handle != adev->handle)
acpi_execute_reg_methods(adev->handle, 1, ACPI_ADR_SPACE_EC);
}
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;
}
static const struct acpi_device_id ec_device_ids[] = {
{"PNP0C09", 0},
{ACPI_ECDT_HID, 0},
{"", 0},
};
/*
* This function is not Windows-compatible as Windows never enumerates the
* namespace EC before the main ACPI device enumeration process. It is
* retained for historical reason and will be deprecated in the future.
*/
void __init acpi_ec_dsdt_probe(void)
{
struct acpi_ec *ec;
acpi_status status;
int ret;
/*
* If a platform has ECDT, there is no need to proceed as the
* following probe is not a part of the ACPI device enumeration,
* executing _STA is not safe, and thus this probe may risk of
* picking up an invalid EC device.
*/
if (boot_ec)
return;
ec = acpi_ec_alloc();
if (!ec)
return;
/*
* At this point, the namespace is initialized, so start to find
* the namespace objects.
*/
status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device, ec, NULL);
if (ACPI_FAILURE(status) || !ec->handle) {
acpi_ec_free(ec);
return;
}
/*
* When the DSDT EC is available, always re-configure boot EC to
* have _REG evaluated. _REG can only be evaluated after the
* namespace initialization.
* At this point, the GPE is not fully initialized, so do not to
* handle the events.
*/
ret = acpi_ec_setup(ec, NULL, true);
if (ret) {
acpi_ec_free(ec);
return;
}
boot_ec = ec;
acpi_handle_info(ec->handle,
"Boot DSDT EC used to handle transactions\n");
}
/*
* acpi_ec_ecdt_start - Finalize the boot ECDT EC initialization.
*
* First, look for an ACPI handle for the boot ECDT EC if acpi_ec_add() has not
* found a matching object in the namespace.
*
* Next, in case the DSDT EC is not functioning, it is still necessary to
* provide a functional ECDT EC to handle events, so add an extra device object
* to represent it (see https://bugzilla.kernel.org/show_bug.cgi?id=115021).
*
* This is useful on platforms with valid ECDT and invalid DSDT EC settings,
* like ASUS X550ZE (see https://bugzilla.kernel.org/show_bug.cgi?id=196847).
*/
static void __init acpi_ec_ecdt_start(void)
{
struct acpi_table_ecdt *ecdt_ptr;
acpi_handle handle;
acpi_status status;
/* Bail out if a matching EC has been found in the namespace. */
if (!boot_ec || boot_ec->handle != ACPI_ROOT_OBJECT)
return;
/* Look up the object pointed to from the ECDT in the namespace. */
status = acpi_get_table(ACPI_SIG_ECDT, 1,
(struct acpi_table_header **)&ecdt_ptr);
if (ACPI_FAILURE(status))
return;
status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
if (ACPI_SUCCESS(status)) {
boot_ec->handle = handle;
/* Add a special ACPI device object to represent the boot EC. */
acpi_bus_register_early_device(ACPI_BUS_TYPE_ECDT_EC);
}
acpi_put_table((struct acpi_table_header *)ecdt_ptr);
}
/*
* 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;
ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
return 0;
}
/*
* Some ECDTs contain wrong register addresses.
* MSI MS-171F
* https://bugzilla.kernel.org/show_bug.cgi?id=12461
*/
static int ec_correct_ecdt(const struct dmi_system_id *id)
{
pr_debug("Detected system needing ECDT address correction.\n");
EC_FLAGS_CORRECT_ECDT = 1;
return 0;
}
/*
* Some ECDTs contain wrong GPE setting, but they share the same port addresses
* with DSDT EC, don't duplicate the DSDT EC with ECDT EC in this case.
* https://bugzilla.kernel.org/show_bug.cgi?id=209989
*/
static int ec_honor_dsdt_gpe(const struct dmi_system_id *id)
{
pr_debug("Detected system needing DSDT GPE setting.\n");
EC_FLAGS_TRUST_DSDT_GPE = 1;
return 0;
}
static const struct dmi_system_id ec_dmi_table[] __initconst = {
{
/*
* MSI MS-171F
* https://bugzilla.kernel.org/show_bug.cgi?id=12461
*/
.callback = ec_correct_ecdt,
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),
},
},
{
/*
* HP Pavilion Gaming Laptop 15-cx0xxx
* https://bugzilla.kernel.org/show_bug.cgi?id=209989
*/
.callback = ec_honor_dsdt_gpe,
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "HP"),
DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion Gaming Laptop 15-cx0xxx"),
},
},
{
/*
* HP Pavilion Gaming Laptop 15-cx0041ur
*/
.callback = ec_honor_dsdt_gpe,
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "HP"),
DMI_MATCH(DMI_PRODUCT_NAME, "HP 15-cx0041ur"),
},
},
{
/*
* HP Pavilion Gaming Laptop 15-dk1xxx
* https://github.com/systemd/systemd/issues/28942
*/
.callback = ec_honor_dsdt_gpe,
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "HP"),
DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion Gaming Laptop 15-dk1xxx"),
},
},
{
/*
* HP 250 G7 Notebook PC
*/
.callback = ec_honor_dsdt_gpe,
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "HP"),
DMI_MATCH(DMI_PRODUCT_NAME, "HP 250 G7 Notebook PC"),
},
},
{
/*
* Samsung hardware
* https://bugzilla.kernel.org/show_bug.cgi?id=44161
*/
.callback = ec_clear_on_resume,
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
},
},
{}
};
void __init acpi_ec_ecdt_probe(void)
{
struct acpi_table_ecdt *ecdt_ptr;
struct acpi_ec *ec;
acpi_status status;
int ret;
/* 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_FAILURE(status))
return;
if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
/*
* Asus X50GL:
* https://bugzilla.kernel.org/show_bug.cgi?id=11880
*/
goto out;
}
ec = acpi_ec_alloc();
if (!ec)
goto out;
if (EC_FLAGS_CORRECT_ECDT) {
ec->command_addr = ecdt_ptr->data.address;
ec->data_addr = ecdt_ptr->control.address;
} else {
ec->command_addr = ecdt_ptr->control.address;
ec->data_addr = ecdt_ptr->data.address;
}
/*
* Ignore the GPE value on Reduced Hardware platforms.
* Some products have this set to an erroneous value.
*/
if (!acpi_gbl_reduced_hardware)
ec->gpe = ecdt_ptr->gpe;
ec->handle = ACPI_ROOT_OBJECT;
/*
* At this point, the namespace is not initialized, so do not find
* the namespace objects, or handle the events.
*/
ret = acpi_ec_setup(ec, NULL, false);
if (ret) {
acpi_ec_free(ec);
goto out;
}
boot_ec = ec;
boot_ec_is_ecdt = true;
pr_info("Boot ECDT EC used to handle transactions\n");
out:
acpi_put_table((struct acpi_table_header *)ecdt_ptr);
}
#ifdef CONFIG_PM_SLEEP
static int acpi_ec_suspend(struct device *dev)
{
struct acpi_ec *ec =
acpi_driver_data(to_acpi_device(dev));
if (!pm_suspend_no_platform() && ec_freeze_events)
acpi_ec_disable_event(ec);
return 0;
}
static int acpi_ec_suspend_noirq(struct device *dev)
{
struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
/*
* The SCI handler doesn't run at this point, so the GPE can be
* masked at the low level without side effects.
*/
if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
ec->gpe >= 0 && ec->reference_count >= 1)
acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
acpi_ec_enter_noirq(ec);
return 0;
}
static int acpi_ec_resume_noirq(struct device *dev)
{
struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
acpi_ec_leave_noirq(ec);
if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
ec->gpe >= 0 && ec->reference_count >= 1)
acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
return 0;
}
static int acpi_ec_resume(struct device *dev)
{
struct acpi_ec *ec =
acpi_driver_data(to_acpi_device(dev));
acpi_ec_enable_event(ec);
return 0;
}
void acpi_ec_mark_gpe_for_wake(void)
{
if (first_ec && !ec_no_wakeup)
acpi_mark_gpe_for_wake(NULL, first_ec->gpe);
}
EXPORT_SYMBOL_GPL(acpi_ec_mark_gpe_for_wake);
void acpi_ec_set_gpe_wake_mask(u8 action)
{
if (pm_suspend_no_platform() && first_ec && !ec_no_wakeup)
acpi_set_gpe_wake_mask(NULL, first_ec->gpe, action);
}
static bool acpi_ec_work_in_progress(struct acpi_ec *ec)
{
return ec->events_in_progress + ec->queries_in_progress > 0;
}
bool acpi_ec_dispatch_gpe(void)
{
bool work_in_progress = false;
if (!first_ec)
return acpi_any_gpe_status_set(U32_MAX);
/*
* Report wakeup if the status bit is set for any enabled GPE other
* than the EC one.
*/
if (acpi_any_gpe_status_set(first_ec->gpe))
return true;
/*
* Cancel the SCI wakeup and process all pending events in case there
* are any wakeup ones in there.
*
* Note that if any non-EC GPEs are active at this point, the SCI will
* retrigger after the rearming in acpi_s2idle_wake(), so no events
* should be missed by canceling the wakeup here.
*/
pm_system_cancel_wakeup();
/*
* Dispatch the EC GPE in-band, but do not report wakeup in any case
* to allow the caller to process events properly after that.
*/
spin_lock_irq(&first_ec->lock);
if (acpi_ec_gpe_status_set(first_ec)) {
pm_pr_dbg("ACPI EC GPE status set\n");
clear_gpe_and_advance_transaction(first_ec, false);
work_in_progress = acpi_ec_work_in_progress(first_ec);
}
spin_unlock_irq(&first_ec->lock);
if (!work_in_progress)
return false;
pm_pr_dbg("ACPI EC GPE dispatched\n");
/* Drain EC work. */
do {
acpi_ec_flush_work();
pm_pr_dbg("ACPI EC work flushed\n");
spin_lock_irq(&first_ec->lock);
work_in_progress = acpi_ec_work_in_progress(first_ec);
spin_unlock_irq(&first_ec->lock);
} while (work_in_progress && !pm_wakeup_pending());
return false;
}
#endif /* CONFIG_PM_SLEEP */
static const struct dev_pm_ops acpi_ec_pm = {
SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq)
SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
};
static int param_set_event_clearing(const char *val,
const 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,
const struct kernel_param *kp)
{
switch (ec_event_clearing) {
case ACPI_EC_EVT_TIMING_STATUS:
return sprintf(buffer, "status\n");
case ACPI_EC_EVT_TIMING_QUERY:
return sprintf(buffer, "query\n");
case ACPI_EC_EVT_TIMING_EVENT:
return sprintf(buffer, "event\n");
default:
return sprintf(buffer, "invalid\n");
}
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,
},
.drv.pm = &acpi_ec_pm,
};
static void acpi_ec_destroy_workqueues(void)
{
if (ec_wq) {
destroy_workqueue(ec_wq);
ec_wq = NULL;
}
if (ec_query_wq) {
destroy_workqueue(ec_query_wq);
ec_query_wq = NULL;
}
}
static int acpi_ec_init_workqueues(void)
{
if (!ec_wq)
ec_wq = alloc_ordered_workqueue("kec", 0);
if (!ec_query_wq)
ec_query_wq = alloc_workqueue("kec_query", 0, ec_max_queries);
if (!ec_wq || !ec_query_wq) {
acpi_ec_destroy_workqueues();
return -ENODEV;
}
return 0;
}
static const struct dmi_system_id acpi_ec_no_wakeup[] = {
{
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
DMI_MATCH(DMI_PRODUCT_FAMILY, "Thinkpad X1 Carbon 6th"),
},
},
{
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Yoga 3rd"),
},
},
{
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "HP"),
DMI_MATCH(DMI_PRODUCT_FAMILY, "103C_5336AN HP ZHAN 66 Pro"),
},
},
{ },
};
void __init acpi_ec_init(void)
{
int result;
result = acpi_ec_init_workqueues();
if (result)
return;
/*
* Disable EC wakeup on following systems to prevent periodic
* wakeup from EC GPE.
*/
if (dmi_check_system(acpi_ec_no_wakeup)) {
ec_no_wakeup = true;
pr_debug("Disabling EC wakeup on suspend-to-idle\n");
}
/* Driver must be registered after acpi_ec_init_workqueues(). */
acpi_bus_register_driver(&acpi_ec_driver);
acpi_ec_ecdt_start();
}
/* EC driver currently not unloadable */
#if 0
static void __exit acpi_ec_exit(void)
{
acpi_bus_unregister_driver(&acpi_ec_driver);
acpi_ec_destroy_workqueues();
}
#endif /* 0 */
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