# Copyright (c) 2014 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
import glob
import logging
import os
from autotest_lib.client.bin import test, utils
from autotest_lib.client.common_lib import error
class kernel_Delay(test.test):
"""
Test to ensure that udelay() delays at least as long as requested
(as compared to ktime()).
Test a variety of delays at mininmum and maximum cpu frequencies.
"""
version = 1
MIN_KERNEL_VER = '3.8'
MODULE_NAME = 'udelay_test'
UDELAY_PATH = '/sys/kernel/debug/udelay_test'
QUIET_GOVERNOR_PATH = '/sys/devices/system/cpu/cpuquiet/current_governor'
GOVERNOR_GLOB = '/sys/devices/system/cpu/cpu*/cpufreq/scaling_governor'
SETSPEED_GLOB = '/sys/devices/system/cpu/cpu*/cpufreq/scaling_setspeed'
CUR_FREQ_GLOB = '/sys/devices/system/cpu/cpu*/cpufreq/cpuinfo_cur_freq'
CPUFREQ_AVAIL_PATH = (
'/sys/devices/system/cpu/cpu0/cpufreq/'
'scaling_available_frequencies')
# Test a variety of delays
# 1..200, 200..500 (by 10), 500..2000 (by 100)
DELAYS = range(1, 200) + range(200, 500, 10) + range(500, 2001, 100)
ITERATIONS = 100
_governor_paths = []
_setspeed_paths = []
_cur_freq_paths = []
def _set_file(self, contents, filename):
"""
Write a string to a file.
@param contents: the contents to write to the file
@param filename: the filename to use
"""
logging.debug('setting %s to %s', filename, contents)
with open(filename, 'w') as f:
f.write(contents)
def _get_file(self, filename):
"""
Read a string from a file.
@returns: the contents of the file (string)
"""
with open(filename, 'r') as f:
return f.read()
def _get_freqs(self):
"""
Get the current CPU frequencies.
@returns: the CPU frequencies of each CPU (list of int)
"""
return [int(self._get_file(p)) for p in self._cur_freq_paths]
def _get_freqs_string(self):
"""
Get the current CPU frequencies.
@returns: the CPU frequencies of each CPU (string)
"""
return ' '.join(str(x) for x in self._get_freqs())
def _get_governors(self):
"""
Get the current CPU governors.
@returns: the CPU governors of each CPU (list of string)
"""
return [self._get_file(p).rstrip() for p in self._governor_paths]
def _get_quiet_governor(self):
"""
Get the current CPU quiet governor.
@returns: the CPU quiet governor or None if it does not exist (string)
"""
if os.path.isfile(self.QUIET_GOVERNOR_PATH):
return self._get_file(self.QUIET_GOVERNOR_PATH).rstrip()
else:
return None
def _reset_freq(self, initial_governors, initial_quiet_governor):
"""
Unlimit the CPU frequency.
@param initial_governors: list of initial governors to reset state to
@param initial_quiet_governor: initial quiet governor to reset state to
"""
for p, g in zip(self._governor_paths, initial_governors):
self._set_file(g, p)
if initial_quiet_governor and os.path.isfile(self.QUIET_GOVERNOR_PATH):
self._set_file(initial_quiet_governor, self.QUIET_GOVERNOR_PATH)
def _set_freq(self, freq):
"""
Set the CPU frequency.
@param freq: desired CPU frequency
"""
# Prevent CPUs from going up and down during the test if the option
# is available.
if os.path.isfile(self.QUIET_GOVERNOR_PATH):
logging.info('changing to userspace cpuquiet governor');
self._set_file('userspace', self.QUIET_GOVERNOR_PATH)
for p in self._governor_paths:
self._set_file('userspace', p)
for p in self._setspeed_paths:
self._set_file(str(freq), p)
logging.info(
'cpu frequencies set to %s with userspace governor',
self._get_freqs_string())
self._check_freq(freq)
def _check_freq(self, freq):
"""
Check the CPU frequencies are set as requested.
@param freq: desired CPU frequency
"""
for p in self._governor_paths:
governor = self._get_file(p).rstrip()
if governor != 'userspace':
raise error.TestFail('governor changed from userspace to %s' % (
governor))
for p in self._setspeed_paths:
speed = int(self._get_file(p))
if speed != freq:
raise error.TestFail('setspeed changed from %s to %s' % (
freq, speed))
freqs = self._get_freqs()
for f in freqs:
if f != freq:
raise error.TestFail('frequency set to %s instead of %s' % (
f, freq))
def _test_udelay(self, usecs):
"""
Test udelay() for a given amount of time.
@param usecs: number of usecs to delay for each iteration
"""
self._set_file('%d %d' % (usecs, self.ITERATIONS), self.UDELAY_PATH)
with open(self.UDELAY_PATH, 'r') as f:
for line in f:
line = line.rstrip()
logging.info('result: %s', line)
if 'FAIL' in line:
raise error.TestFail('udelay failed: %s' % line)
def run_once(self):
kernel_ver = os.uname()[2]
if utils.compare_versions(kernel_ver, self.MIN_KERNEL_VER) < 0:
logging.info(
'skipping test: old kernel %s (min %s) missing module %s',
kernel_ver, self.MIN_KERNEL_VER, self.MODULE_NAME)
return
utils.load_module(self.MODULE_NAME)
self._governor_paths = glob.glob(self.GOVERNOR_GLOB)
self._setspeed_paths = glob.glob(self.SETSPEED_GLOB)
self._cur_freq_paths = glob.glob(self.CUR_FREQ_GLOB)
initial_governors = self._get_governors()
initial_quiet_governor = self._get_quiet_governor()
with open(self.CPUFREQ_AVAIL_PATH, 'r') as f:
available_freqs = [int(x) for x in f.readline().split()]
max_freq = max(available_freqs)
min_freq = min(available_freqs)
logging.info('cpu frequency max %d min %d', max_freq, min_freq)
freqs = [ min_freq, max_freq ]
try:
for freq in freqs:
self._set_freq(freq)
for usecs in self.DELAYS:
self._test_udelay(usecs)
self._check_freq(freq)
finally:
self._reset_freq(initial_governors, initial_quiet_governor)
utils.unload_module(self.MODULE_NAME)