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/time.h>
23 
24 #include "timekeeping_internal.h"
25 
26 #define NUM_BINS 32
27 
28 static unsigned int sleep_time_bin[NUM_BINS] = {0};
29 
30 static int tk_debug_show_sleep_time(struct seq_file *s, void *data)
31 {
32 	unsigned int bin;
33 	seq_puts(s, "      time (secs)        count\n");
34 	seq_puts(s, "------------------------------\n");
35 	for (bin = 0; bin < 32; bin++) {
36 		if (sleep_time_bin[bin] == 0)
37 			continue;
38 		seq_printf(s, "%10u - %-10u %4u\n",
39 			bin ? 1 << (bin - 1) : 0, 1 << bin,
40 				sleep_time_bin[bin]);
41 	}
42 	return 0;
43 }
44 
45 static int tk_debug_sleep_time_open(struct inode *inode, struct file *file)
46 {
47 	return single_open(file, tk_debug_show_sleep_time, NULL);
48 }
49 
50 static const struct file_operations tk_debug_sleep_time_fops = {
51 	.open		= tk_debug_sleep_time_open,
52 	.read		= seq_read,
53 	.llseek		= seq_lseek,
54 	.release	= single_release,
55 };
56 
57 static int __init tk_debug_sleep_time_init(void)
58 {
59 	struct dentry *d;
60 
61 	d = debugfs_create_file("sleep_time", 0444, NULL, NULL,
62 		&tk_debug_sleep_time_fops);
63 	if (!d) {
64 		pr_err("Failed to create sleep_time debug file\n");
65 		return -ENOMEM;
66 	}
67 
68 	return 0;
69 }
70 late_initcall(tk_debug_sleep_time_init);
71 
72 void tk_debug_account_sleep_time(struct timespec64 *t)
73 {
74 	/* Cap bin index so we don't overflow the array */
75 	int bin = min(fls(t->tv_sec), NUM_BINS-1);
76 
77 	sleep_time_bin[bin]++;
78 	printk_deferred(KERN_INFO "Suspended for %lld.%03lu seconds\n",
79 			(s64)t->tv_sec, t->tv_nsec / NSEC_PER_MSEC);
80 }
81 
82