xref: /linux/tools/time/udelay_test.sh (revision c0c914eca7f251c70facc37dfebeaf176601918d)
1#!/bin/bash
2
3# udelay() test script
4#
5# Test is executed by writing and reading to /sys/kernel/debug/udelay_test
6# and exercises a variety of delays to ensure that udelay() is delaying
7# at least as long as requested (as compared to ktime).
8#
9# Copyright (C) 2014 Google, Inc.
10#
11# This software is licensed under the terms of the GNU General Public
12# License version 2, as published by the Free Software Foundation, and
13# may be copied, distributed, and modified under those terms.
14#
15# This program is distributed in the hope that it will be useful,
16# but WITHOUT ANY WARRANTY; without even the implied warranty of
17# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18# GNU General Public License for more details.
19
20MODULE_NAME=udelay_test
21UDELAY_PATH=/sys/kernel/debug/udelay_test
22
23setup()
24{
25	/sbin/modprobe -q $MODULE_NAME
26	tmp_file=`mktemp`
27}
28
29test_one()
30{
31	delay=$1
32	echo $delay > $UDELAY_PATH
33	tee -a $tmp_file < $UDELAY_PATH
34}
35
36cleanup()
37{
38	if [ -f $tmp_file ]; then
39		rm $tmp_file
40	fi
41	/sbin/modprobe -q -r $MODULE_NAME
42}
43
44trap cleanup EXIT
45setup
46
47# Delay for a variety of times.
48# 1..200, 200..500 (by 10), 500..2000 (by 100)
49for (( delay = 1; delay < 200; delay += 1 )); do
50	test_one $delay
51done
52for (( delay = 200; delay < 500; delay += 10 )); do
53	test_one $delay
54done
55for (( delay = 500; delay <= 2000; delay += 100 )); do
56	test_one $delay
57done
58
59# Search for failures
60count=`grep -c FAIL $tmp_file`
61if [ $? -eq "0" ]; then
62	echo "ERROR: $count delays failed to delay long enough"
63	retcode=1
64fi
65
66exit $retcode
67