2 * debugfs file to track time spent in suspend
4 * Copyright (c) 2011, Google, Inc.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
17 #include <linux/debugfs.h>
18 #include <linux/err.h>
19 #include <linux/init.h>
20 #include <linux/kernel.h>
21 #include <linux/seq_file.h>
22 #include <linux/syscore_ops.h>
23 #include <linux/time.h>
25 static struct timespec suspend_time_before;
26 static unsigned int time_in_suspend_bins[32];
28 #ifdef CONFIG_DEBUG_FS
29 static int suspend_time_debug_show(struct seq_file *s, void *data)
32 seq_printf(s, "time (secs) count\n");
33 seq_printf(s, "------------------\n");
34 for (bin = 0; bin < 32; bin++) {
35 if (time_in_suspend_bins[bin] == 0)
37 seq_printf(s, "%4d - %4d %4u\n",
38 bin ? 1 << (bin - 1) : 0, 1 << bin,
39 time_in_suspend_bins[bin]);
44 static int suspend_time_debug_open(struct inode *inode, struct file *file)
46 return single_open(file, suspend_time_debug_show, NULL);
49 static const struct file_operations suspend_time_debug_fops = {
50 .open = suspend_time_debug_open,
53 .release = single_release,
56 static int __init suspend_time_debug_init(void)
60 d = debugfs_create_file("suspend_time", 0755, NULL, NULL,
61 &suspend_time_debug_fops);
63 pr_err("Failed to create suspend_time debug file\n");
70 late_initcall(suspend_time_debug_init);
73 static int suspend_time_syscore_suspend(void)
75 read_persistent_clock(&suspend_time_before);
80 static void suspend_time_syscore_resume(void)
82 struct timespec after;
84 read_persistent_clock(&after);
86 after = timespec_sub(after, suspend_time_before);
88 time_in_suspend_bins[fls(after.tv_sec)]++;
90 pr_info("Suspended for %lu.%03lu seconds\n", after.tv_sec,
91 after.tv_nsec / NSEC_PER_MSEC);
94 static struct syscore_ops suspend_time_syscore_ops = {
95 .suspend = suspend_time_syscore_suspend,
96 .resume = suspend_time_syscore_resume,
99 static int suspend_time_syscore_init(void)
101 register_syscore_ops(&suspend_time_syscore_ops);
106 static void suspend_time_syscore_exit(void)
108 unregister_syscore_ops(&suspend_time_syscore_ops);
110 module_init(suspend_time_syscore_init);
111 module_exit(suspend_time_syscore_exit);