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Diffstat (limited to 'kernel/power/suspend_time.c')
-rw-r--r--kernel/power/suspend_time.c111
1 files changed, 111 insertions, 0 deletions
diff --git a/kernel/power/suspend_time.c b/kernel/power/suspend_time.c
new file mode 100644
index 00000000000..d2a65da9f22
--- /dev/null
+++ b/kernel/power/suspend_time.c
@@ -0,0 +1,111 @@
1/*
2 * debugfs file to track time spent in suspend
3 *
4 * Copyright (c) 2011, Google, Inc.
5 *
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.
10 *
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
14 * more details.
15 */
16
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>
24
25static struct timespec suspend_time_before;
26static unsigned int time_in_suspend_bins[32];
27
28#ifdef CONFIG_DEBUG_FS
29static int suspend_time_debug_show(struct seq_file *s, void *data)
30{
31 int bin;
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)
36 continue;
37 seq_printf(s, "%4d - %4d %4u\n",
38 bin ? 1 << (bin - 1) : 0, 1 << bin,
39 time_in_suspend_bins[bin]);
40 }
41 return 0;
42}
43
44static int suspend_time_debug_open(struct inode *inode, struct file *file)
45{
46 return single_open(file, suspend_time_debug_show, NULL);
47}
48
49static const struct file_operations suspend_time_debug_fops = {
50 .open = suspend_time_debug_open,
51 .read = seq_read,
52 .llseek = seq_lseek,
53 .release = single_release,
54};
55
56static int __init suspend_time_debug_init(void)
57{
58 struct dentry *d;
59
60 d = debugfs_create_file("suspend_time", 0755, NULL, NULL,
61 &suspend_time_debug_fops);
62 if (!d) {
63 pr_err("Failed to create suspend_time debug file\n");
64 return -ENOMEM;
65 }
66
67 return 0;
68}
69
70late_initcall(suspend_time_debug_init);
71#endif
72
73static int suspend_time_syscore_suspend(void)
74{
75 read_persistent_clock(&suspend_time_before);
76
77 return 0;
78}
79
80static void suspend_time_syscore_resume(void)
81{
82 struct timespec after;
83
84 read_persistent_clock(&after);
85
86 after = timespec_sub(after, suspend_time_before);
87
88 time_in_suspend_bins[fls(after.tv_sec)]++;
89
90 pr_info("Suspended for %lu.%03lu seconds\n", after.tv_sec,
91 after.tv_nsec / NSEC_PER_MSEC);
92}
93
94static struct syscore_ops suspend_time_syscore_ops = {
95 .suspend = suspend_time_syscore_suspend,
96 .resume = suspend_time_syscore_resume,
97};
98
99static int suspend_time_syscore_init(void)
100{
101 register_syscore_ops(&suspend_time_syscore_ops);
102
103 return 0;
104}
105
106static void suspend_time_syscore_exit(void)
107{
108 unregister_syscore_ops(&suspend_time_syscore_ops);
109}
110module_init(suspend_time_syscore_init);
111module_exit(suspend_time_syscore_exit);