autosuspend_wakeup_count.c revision a2582c2c4d20684b21aaf50913a27239789bf5eb 
1/*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <errno.h>
18#include <fcntl.h>
19#include <pthread.h>
20#include <semaphore.h>
21#include <stddef.h>
22#include <string.h>
23#include <sys/stat.h>
24#include <sys/types.h>
25#include <unistd.h>
26
27#define LOG_TAG "libsuspend"
28#include <cutils/log.h>
29
30#include "autosuspend_ops.h"
31
32#define SYS_POWER_STATE "/sys/power/state"
33#define SYS_POWER_WAKEUP_COUNT "/sys/power/wakeup_count"
34
35static int state_fd;
36static int wakeup_count_fd;
37static pthread_t suspend_thread;
38static sem_t suspend_lockout;
39static const char *sleep_state = "mem";
40
41static void *suspend_thread_func(void *arg)
42{
43    char buf[80];
44    char wakeup_count[20];
45    int wakeup_count_len;
46    int ret;
47
48    while (1) {
49        usleep(100000);
50        ALOGV("%s: read wakeup_count\n", __func__);
51        lseek(wakeup_count_fd, 0, SEEK_SET);
52        wakeup_count_len = read(wakeup_count_fd, wakeup_count, sizeof(wakeup_count));
53        if (wakeup_count_len < 0) {
54            strerror_r(errno, buf, sizeof(buf));
55            ALOGE("Error reading from %s: %s\n", SYS_POWER_WAKEUP_COUNT, buf);
56            wakeup_count_len = 0;
57            continue;
58        }
59        if (!wakeup_count_len) {
60            ALOGE("Empty wakeup count\n");
61            continue;
62        }
63
64        ALOGV("%s: wait\n", __func__);
65        ret = sem_wait(&suspend_lockout);
66        if (ret < 0) {
67            strerror_r(errno, buf, sizeof(buf));
68            ALOGE("Error waiting on semaphore: %s\n", buf);
69            continue;
70        }
71
72        ALOGV("%s: write %*s to wakeup_count\n", __func__, wakeup_count_len, wakeup_count);
73        ret = write(wakeup_count_fd, wakeup_count, wakeup_count_len);
74        if (ret < 0) {
75            strerror_r(errno, buf, sizeof(buf));
76            ALOGE("Error writing to %s: %s\n", SYS_POWER_WAKEUP_COUNT, buf);
77        } else {
78            ALOGV("%s: write %s to %s\n", __func__, sleep_state, SYS_POWER_STATE);
79            ret = write(state_fd, sleep_state, strlen(sleep_state));
80            if (ret < 0) {
81                strerror_r(errno, buf, sizeof(buf));
82                ALOGE("Error writing to %s: %s\n", SYS_POWER_STATE, buf);
83            }
84        }
85
86        ALOGV("%s: release sem\n", __func__);
87        ret = sem_post(&suspend_lockout);
88        if (ret < 0) {
89            strerror_r(errno, buf, sizeof(buf));
90            ALOGE("Error releasing semaphore: %s\n", buf);
91        }
92    }
93    return NULL;
94}
95
96static int autosuspend_wakeup_count_enable(void)
97{
98    char buf[80];
99    int ret;
100
101    ALOGV("autosuspend_wakeup_count_enable\n");
102
103    ret = sem_post(&suspend_lockout);
104
105    if (ret < 0) {
106        strerror_r(errno, buf, sizeof(buf));
107        ALOGE("Error changing semaphore: %s\n", buf);
108    }
109
110    ALOGV("autosuspend_wakeup_count_enable done\n");
111
112    return ret;
113}
114
115static int autosuspend_wakeup_count_disable(void)
116{
117    char buf[80];
118    int ret;
119
120    ALOGV("autosuspend_wakeup_count_disable\n");
121
122    ret = sem_wait(&suspend_lockout);
123
124    if (ret < 0) {
125        strerror_r(errno, buf, sizeof(buf));
126        ALOGE("Error changing semaphore: %s\n", buf);
127    }
128
129    ALOGV("autosuspend_wakeup_count_disable done\n");
130
131    return ret;
132}
133
134struct autosuspend_ops autosuspend_wakeup_count_ops = {
135        .enable = autosuspend_wakeup_count_enable,
136        .disable = autosuspend_wakeup_count_disable,
137};
138
139struct autosuspend_ops *autosuspend_wakeup_count_init(void)
140{
141    int ret;
142    char buf[80];
143
144    state_fd = open(SYS_POWER_STATE, O_RDWR);
145    if (state_fd < 0) {
146        strerror_r(errno, buf, sizeof(buf));
147        ALOGE("Error opening %s: %s\n", SYS_POWER_STATE, buf);
148        goto err_open_state;
149    }
150
151    wakeup_count_fd = open(SYS_POWER_WAKEUP_COUNT, O_RDWR);
152    if (wakeup_count_fd < 0) {
153        strerror_r(errno, buf, sizeof(buf));
154        ALOGE("Error opening %s: %s\n", SYS_POWER_WAKEUP_COUNT, buf);
155        goto err_open_wakeup_count;
156    }
157
158    ret = sem_init(&suspend_lockout, 0, 0);
159    if (ret < 0) {
160        strerror_r(errno, buf, sizeof(buf));
161        ALOGE("Error creating semaphore: %s\n", buf);
162        goto err_sem_init;
163    }
164    ret = pthread_create(&suspend_thread, NULL, suspend_thread_func, NULL);
165    if (ret) {
166        strerror_r(ret, buf, sizeof(buf));
167        ALOGE("Error creating thread: %s\n", buf);
168        goto err_pthread_create;
169    }
170
171    ALOGI("Selected wakeup count\n");
172    return &autosuspend_wakeup_count_ops;
173
174err_pthread_create:
175    sem_destroy(&suspend_lockout);
176err_sem_init:
177    close(wakeup_count_fd);
178err_open_wakeup_count:
179    close(state_fd);
180err_open_state:
181    return NULL;
182}
183