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