xref: /linux/kernel/time/timekeeping_debug.c (revision ef69f8d2ff09518657c3ecaf2db8408c16549829)
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/suspend.h>
23 #include <linux/time.h>
24 
25 #include "timekeeping_internal.h"
26 
27 #define NUM_BINS 32
28 
29 static unsigned int sleep_time_bin[NUM_BINS] = {0};
30 
31 static int tk_debug_show_sleep_time(struct seq_file *s, void *data)
32 {
33 	unsigned int bin;
34 	seq_puts(s, "      time (secs)        count\n");
35 	seq_puts(s, "------------------------------\n");
36 	for (bin = 0; bin < 32; bin++) {
37 		if (sleep_time_bin[bin] == 0)
38 			continue;
39 		seq_printf(s, "%10u - %-10u %4u\n",
40 			bin ? 1 << (bin - 1) : 0, 1 << bin,
41 				sleep_time_bin[bin]);
42 	}
43 	return 0;
44 }
45 
46 static int tk_debug_sleep_time_open(struct inode *inode, struct file *file)
47 {
48 	return single_open(file, tk_debug_show_sleep_time, NULL);
49 }
50 
51 static const struct file_operations tk_debug_sleep_time_fops = {
52 	.open		= tk_debug_sleep_time_open,
53 	.read		= seq_read,
54 	.llseek		= seq_lseek,
55 	.release	= single_release,
56 };
57 
58 static int __init tk_debug_sleep_time_init(void)
59 {
60 	struct dentry *d;
61 
62 	d = debugfs_create_file("sleep_time", 0444, NULL, NULL,
63 		&tk_debug_sleep_time_fops);
64 	if (!d) {
65 		pr_err("Failed to create sleep_time debug file\n");
66 		return -ENOMEM;
67 	}
68 
69 	return 0;
70 }
71 late_initcall(tk_debug_sleep_time_init);
72 
73 void tk_debug_account_sleep_time(struct timespec64 *t)
74 {
75 	/* Cap bin index so we don't overflow the array */
76 	int bin = min(fls(t->tv_sec), NUM_BINS-1);
77 
78 	sleep_time_bin[bin]++;
79 	pm_deferred_pr_dbg("Timekeeping suspended for %lld.%03lu seconds\n",
80 			   (s64)t->tv_sec, t->tv_nsec / NSEC_PER_MSEC);
81 }
82 
83