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/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define LOG_TAG "libsuspend"
//#define LOG_NDEBUG 0
#include <fcntl.h>
#include <pthread.h>
#include <semaphore.h>
#include <stdbool.h>
#include <stddef.h>
#include <string.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/strings.h>
#include "autosuspend_ops.h"
#define BASE_SLEEP_TIME 100000
#define MAX_SLEEP_TIME 60000000
static int state_fd = -1;
static int wakeup_count_fd;
using android::base::ReadFdToString;
using android::base::Trim;
using android::base::WriteStringToFd;
static pthread_t suspend_thread;
static sem_t suspend_lockout;
static constexpr char sleep_state[] = "mem";
static void (*wakeup_func)(bool success) = NULL;
static int sleep_time = BASE_SLEEP_TIME;
static constexpr char sys_power_state[] = "/sys/power/state";
static constexpr char sys_power_wakeup_count[] = "/sys/power/wakeup_count";
static bool autosuspend_is_init = false;
static void update_sleep_time(bool success) {
if (success) {
sleep_time = BASE_SLEEP_TIME;
return;
}
// double sleep time after each failure up to one minute
sleep_time = MIN(sleep_time * 2, MAX_SLEEP_TIME);
}
static void* suspend_thread_func(void* arg __attribute__((unused))) {
bool success = true;
while (true) {
update_sleep_time(success);
usleep(sleep_time);
success = false;
LOG(VERBOSE) << "read wakeup_count";
lseek(wakeup_count_fd, 0, SEEK_SET);
std::string wakeup_count;
if (!ReadFdToString(wakeup_count_fd, &wakeup_count)) {
PLOG(ERROR) << "error reading from " << sys_power_wakeup_count;
continue;
}
wakeup_count = Trim(wakeup_count);
if (wakeup_count.empty()) {
LOG(ERROR) << "empty wakeup count";
continue;
}
LOG(VERBOSE) << "wait";
int ret = sem_wait(&suspend_lockout);
if (ret < 0) {
PLOG(ERROR) << "error waiting on semaphore";
continue;
}
LOG(VERBOSE) << "write " << wakeup_count << " to wakeup_count";
if (WriteStringToFd(wakeup_count, wakeup_count_fd)) {
LOG(VERBOSE) << "write " << sleep_state << " to " << sys_power_state;
success = WriteStringToFd(sleep_state, state_fd);
void (*func)(bool success) = wakeup_func;
if (func != NULL) {
(*func)(success);
}
} else {
PLOG(ERROR) << "error writing to " << sys_power_wakeup_count;
}
LOG(VERBOSE) << "release sem";
ret = sem_post(&suspend_lockout);
if (ret < 0) {
PLOG(ERROR) << "error releasing semaphore";
}
}
return NULL;
}
static int init_state_fd(void) {
if (state_fd >= 0) {
return 0;
}
int fd = TEMP_FAILURE_RETRY(open(sys_power_state, O_CLOEXEC | O_RDWR));
if (fd < 0) {
PLOG(ERROR) << "error opening " << sys_power_state;
return -1;
}
state_fd = fd;
LOG(INFO) << "init_state_fd success";
return 0;
}
static int autosuspend_init(void) {
if (autosuspend_is_init) {
return 0;
}
int ret = init_state_fd();
if (ret < 0) {
return -1;
}
wakeup_count_fd = TEMP_FAILURE_RETRY(open(sys_power_wakeup_count, O_CLOEXEC | O_RDWR));
if (wakeup_count_fd < 0) {
PLOG(ERROR) << "error opening " << sys_power_wakeup_count;
goto err_open_wakeup_count;
}
ret = sem_init(&suspend_lockout, 0, 0);
if (ret < 0) {
PLOG(ERROR) << "error creating suspend_lockout semaphore";
goto err_sem_init;
}
ret = pthread_create(&suspend_thread, NULL, suspend_thread_func, NULL);
if (ret) {
LOG(ERROR) << "error creating thread: " << strerror(ret);
goto err_pthread_create;
}
LOG(VERBOSE) << "autosuspend_init success";
autosuspend_is_init = true;
return 0;
err_pthread_create:
sem_destroy(&suspend_lockout);
err_sem_init:
close(wakeup_count_fd);
err_open_wakeup_count:
return -1;
}
static int autosuspend_wakeup_count_enable(void) {
LOG(VERBOSE) << "autosuspend_wakeup_count_enable";
int ret = autosuspend_init();
if (ret < 0) {
LOG(ERROR) << "autosuspend_init failed";
return ret;
}
ret = sem_post(&suspend_lockout);
if (ret < 0) {
PLOG(ERROR) << "error changing semaphore";
}
LOG(VERBOSE) << "autosuspend_wakeup_count_enable done";
return ret;
}
static int autosuspend_wakeup_count_disable(void) {
LOG(VERBOSE) << "autosuspend_wakeup_count_disable";
if (!autosuspend_is_init) {
return 0; // always successful if no thread is running yet
}
int ret = sem_wait(&suspend_lockout);
if (ret < 0) {
PLOG(ERROR) << "error changing semaphore";
}
LOG(VERBOSE) << "autosuspend_wakeup_count_disable done";
return ret;
}
static int force_suspend(int timeout_ms) {
LOG(VERBOSE) << "force_suspend called with timeout: " << timeout_ms;
int ret = init_state_fd();
if (ret < 0) {
return ret;
}
return WriteStringToFd(sleep_state, state_fd) ? 0 : -1;
}
static void autosuspend_set_wakeup_callback(void (*func)(bool success)) {
if (wakeup_func != NULL) {
LOG(ERROR) << "duplicate wakeup callback applied, keeping original";
return;
}
wakeup_func = func;
}
struct autosuspend_ops autosuspend_wakeup_count_ops = {
.enable = autosuspend_wakeup_count_enable,
.disable = autosuspend_wakeup_count_disable,
.force_suspend = force_suspend,
.set_wakeup_callback = autosuspend_set_wakeup_callback,
};
struct autosuspend_ops* autosuspend_wakeup_count_init(void) {
return &autosuspend_wakeup_count_ops;
}
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