tools/time/udelay_test.sh

   1 #!/bin/bash
   2 # SPDX-License-Identifier: GPL-2.0-only
   3
   4 # udelay() test script
   5 #
   6 # Test is executed by writing and reading to /sys/kernel/debug/udelay_test
   7 # and exercises a variety of delays to ensure that udelay() is delaying
   8 # at least as long as requested (as compared to ktime).
   9 #
  10 # Copyright (C) 2014 Google, Inc.
  11 #
  12
  13 MODULE_NAME=udelay_test
  14 UDELAY_PATH=/sys/kernel/debug/udelay_test
  15
  16 setup()
  17 {
  18         /sbin/modprobe -q $MODULE_NAME
  19         tmp_file=`mktemp`
  20 }
  21
  22 test_one()
  23 {
  24         delay=$1
  25         echo $delay > $UDELAY_PATH
  26         tee -a $tmp_file < $UDELAY_PATH
  27 }
  28
  29 cleanup()
  30 {
  31         if [ -f $tmp_file ]; then
  32                 rm $tmp_file
  33         fi
  34         /sbin/modprobe -q -r $MODULE_NAME
  35 }
  36
  37 trap cleanup EXIT
  38 setup
  39
  40 # Delay for a variety of times.
  41 # 1..200, 200..500 (by 10), 500..2000 (by 100)
  42 for (( delay = 1; delay < 200; delay += 1 )); do
  43         test_one $delay
  44 done
  45 for (( delay = 200; delay < 500; delay += 10 )); do
  46         test_one $delay
  47 done
  48 for (( delay = 500; delay <= 2000; delay += 100 )); do
  49         test_one $delay
  50 done
  51
  52 # Search for failures
  53 count=`grep -c FAIL $tmp_file`
  54 if [ $? -eq "0" ]; then
  55         echo "ERROR: $count delays failed to delay long enough"
  56         retcode=1
  57 fi
  58
  59 exit $retcode