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