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 #define LOG_TAG "libsuspend"
18 //#define LOG_NDEBUG 0
19
20 #include <errno.h>
21 #include <fcntl.h>
22 #include <pthread.h>
23 #include <semaphore.h>
24 #include <stddef.h>
25 #include <stdbool.h>
26 #include <string.h>
27 #include <sys/stat.h>
28 #include <sys/types.h>
29 #include <unistd.h>
30
31 #include <log/log.h>
32
33 #include "autosuspend_ops.h"
34
35 #define SYS_POWER_STATE "/sys/power/state"
36 #define SYS_POWER_WAKEUP_COUNT "/sys/power/wakeup_count"
37
38 static int state_fd;
39 static int wakeup_count_fd;
40 static pthread_t suspend_thread;
41 static sem_t suspend_lockout;
42 static const char *sleep_state = "mem";
43 static void (*wakeup_func)(bool success) = NULL;
44
suspend_thread_func(void * arg)45 static void *suspend_thread_func(void *arg __attribute__((unused)))
46 {
47 char buf[80];
48 char wakeup_count[20];
49 int wakeup_count_len;
50 int ret;
51 bool success;
52
53 while (1) {
54 usleep(100000);
55 ALOGV("%s: read wakeup_count\n", __func__);
56 lseek(wakeup_count_fd, 0, SEEK_SET);
57 wakeup_count_len = TEMP_FAILURE_RETRY(read(wakeup_count_fd, wakeup_count,
58 sizeof(wakeup_count)));
59 if (wakeup_count_len < 0) {
60 strerror_r(errno, buf, sizeof(buf));
61 ALOGE("Error reading from %s: %s\n", SYS_POWER_WAKEUP_COUNT, buf);
62 wakeup_count_len = 0;
63 continue;
64 }
65 if (!wakeup_count_len) {
66 ALOGE("Empty wakeup count\n");
67 continue;
68 }
69
70 ALOGV("%s: wait\n", __func__);
71 ret = sem_wait(&suspend_lockout);
72 if (ret < 0) {
73 strerror_r(errno, buf, sizeof(buf));
74 ALOGE("Error waiting on semaphore: %s\n", buf);
75 continue;
76 }
77
78 success = true;
79 ALOGV("%s: write %*s to wakeup_count\n", __func__, wakeup_count_len, wakeup_count);
80 ret = TEMP_FAILURE_RETRY(write(wakeup_count_fd, wakeup_count, wakeup_count_len));
81 if (ret < 0) {
82 strerror_r(errno, buf, sizeof(buf));
83 ALOGE("Error writing to %s: %s\n", SYS_POWER_WAKEUP_COUNT, buf);
84 } else {
85 ALOGV("%s: write %s to %s\n", __func__, sleep_state, SYS_POWER_STATE);
86 ret = TEMP_FAILURE_RETRY(write(state_fd, sleep_state, strlen(sleep_state)));
87 if (ret < 0) {
88 success = false;
89 }
90 void (*func)(bool success) = wakeup_func;
91 if (func != NULL) {
92 (*func)(success);
93 }
94 }
95
96 ALOGV("%s: release sem\n", __func__);
97 ret = sem_post(&suspend_lockout);
98 if (ret < 0) {
99 strerror_r(errno, buf, sizeof(buf));
100 ALOGE("Error releasing semaphore: %s\n", buf);
101 }
102 }
103 return NULL;
104 }
105
autosuspend_wakeup_count_enable(void)106 static int autosuspend_wakeup_count_enable(void)
107 {
108 char buf[80];
109 int ret;
110
111 ALOGV("autosuspend_wakeup_count_enable\n");
112
113 ret = sem_post(&suspend_lockout);
114
115 if (ret < 0) {
116 strerror_r(errno, buf, sizeof(buf));
117 ALOGE("Error changing semaphore: %s\n", buf);
118 }
119
120 ALOGV("autosuspend_wakeup_count_enable done\n");
121
122 return ret;
123 }
124
autosuspend_wakeup_count_disable(void)125 static int autosuspend_wakeup_count_disable(void)
126 {
127 char buf[80];
128 int ret;
129
130 ALOGV("autosuspend_wakeup_count_disable\n");
131
132 ret = sem_wait(&suspend_lockout);
133
134 if (ret < 0) {
135 strerror_r(errno, buf, sizeof(buf));
136 ALOGE("Error changing semaphore: %s\n", buf);
137 }
138
139 ALOGV("autosuspend_wakeup_count_disable done\n");
140
141 return ret;
142 }
143
set_wakeup_callback(void (* func)(bool success))144 void set_wakeup_callback(void (*func)(bool success))
145 {
146 if (wakeup_func != NULL) {
147 ALOGE("Duplicate wakeup callback applied, keeping original");
148 return;
149 }
150 wakeup_func = func;
151 }
152
153 struct autosuspend_ops autosuspend_wakeup_count_ops = {
154 .enable = autosuspend_wakeup_count_enable,
155 .disable = autosuspend_wakeup_count_disable,
156 };
157
autosuspend_wakeup_count_init(void)158 struct autosuspend_ops *autosuspend_wakeup_count_init(void)
159 {
160 int ret;
161 char buf[80];
162
163 state_fd = TEMP_FAILURE_RETRY(open(SYS_POWER_STATE, O_RDWR));
164 if (state_fd < 0) {
165 strerror_r(errno, buf, sizeof(buf));
166 ALOGE("Error opening %s: %s\n", SYS_POWER_STATE, buf);
167 goto err_open_state;
168 }
169
170 wakeup_count_fd = TEMP_FAILURE_RETRY(open(SYS_POWER_WAKEUP_COUNT, O_RDWR));
171 if (wakeup_count_fd < 0) {
172 strerror_r(errno, buf, sizeof(buf));
173 ALOGE("Error opening %s: %s\n", SYS_POWER_WAKEUP_COUNT, buf);
174 goto err_open_wakeup_count;
175 }
176
177 ret = sem_init(&suspend_lockout, 0, 0);
178 if (ret < 0) {
179 strerror_r(errno, buf, sizeof(buf));
180 ALOGE("Error creating semaphore: %s\n", buf);
181 goto err_sem_init;
182 }
183 ret = pthread_create(&suspend_thread, NULL, suspend_thread_func, NULL);
184 if (ret) {
185 strerror_r(ret, buf, sizeof(buf));
186 ALOGE("Error creating thread: %s\n", buf);
187 goto err_pthread_create;
188 }
189
190 ALOGI("Selected wakeup count\n");
191 return &autosuspend_wakeup_count_ops;
192
193 err_pthread_create:
194 sem_destroy(&suspend_lockout);
195 err_sem_init:
196 close(wakeup_count_fd);
197 err_open_wakeup_count:
198 close(state_fd);
199 err_open_state:
200 return NULL;
201 }
202