tools/time/udelay_test.sh

   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
  20 MODULE_NAME=udelay_test
  21 UDELAY_PATH=/sys/kernel/debug/udelay_test
  22
  23 setup()
  24 {
  25         /sbin/modprobe -q $MODULE_NAME
  26         tmp_file=`mktemp`
  27 }
  28
  29 test_one()
  30 {
  31         delay=$1
  32         echo $delay > $UDELAY_PATH
  33         tee -a $tmp_file < $UDELAY_PATH
  34 }
  35
  36 cleanup()
  37 {
  38         if [ -f $tmp_file ]; then
  39                 rm $tmp_file
  40         fi
  41         /sbin/modprobe -q -r $MODULE_NAME
  42 }
  43
  44 trap cleanup EXIT
  45 setup
  46
  47 # Delay for a variety of times.
  48 # 1..200, 200..500 (by 10), 500..2000 (by 100)
  49 for (( delay = 1; delay < 200; delay += 1 )); do
  50         test_one $delay
  51 done
  52 for (( delay = 200; delay < 500; delay += 10 )); do
  53         test_one $delay
  54 done
  55 for (( delay = 500; delay <= 2000; delay += 100 )); do
  56         test_one $delay
  57 done
  58
  59 # Search for failures
  60 count=`grep -c FAIL $tmp_file`
  61 if [ $? -eq "0" ]; then
  62         echo "ERROR: $count delays failed to delay long enough"
  63         retcode=1
  64 fi
  65
  66 exit $retcode