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
35 static int state_fd;
36 static int wakeup_count_fd;
37 static pthread_t suspend_thread;
38 static sem_t suspend_lockout;
39 static const char *sleep_state = "mem";
40
suspend_thread_func(void * arg)41 static void *suspend_thread_func(void *arg __attribute__((unused)))
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
autosuspend_wakeup_count_enable(void)96 static 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
autosuspend_wakeup_count_disable(void)115 static 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
134 struct autosuspend_ops autosuspend_wakeup_count_ops = {
135 .enable = autosuspend_wakeup_count_enable,
136 .disable = autosuspend_wakeup_count_disable,
137 };
138
autosuspend_wakeup_count_init(void)139 struct 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
174 err_pthread_create:
175 sem_destroy(&suspend_lockout);
176 err_sem_init:
177 close(wakeup_count_fd);
178 err_open_wakeup_count:
179 close(state_fd);
180 err_open_state:
181 return NULL;
182 }
183