Add methods to get/set cpuidle states

Add methods to get/set cpuidle states
in host and selftests for the method.
Signed-off-by: NSatheesh Rajendran <sathnaga@linux.vnet.ibm.com>

avocado/utils/cpu.py

@@ -23,6 +23,8 @@ Get information from the current's machine CPU.
 import re
 import os
 import platform
+import glob
+import logging
 
 
 def _list_matches(lst, pattern):
@@ -195,3 +197,59 @@ def offline(cpu):
     if _get_cpu_status(cpu):
         return 1
     return 0
+
+
+def get_cpuidle_state():
+    """
+    Get current cpu idle values
+
+    :return: Dict of cpuidle states values for all cpus
+    :rtype: Dict of dicts
+    """
+    cpus_list = cpu_online_list()
+    states = range(len(glob.glob("/sys/devices/system/cpu/cpu0/cpuidle/state*")))
+    cpu_idlestate = {}
+    for cpu in cpus_list:
+        cpu_idlestate[cpu] = {}
+        for state_no in states:
+            state_file = "/sys/devices/system/cpu/cpu%s/cpuidle/state%s/disable" % (cpu, state_no)
+            try:
+                cpu_idlestate[cpu][state_no] = int(open(state_file).read())
+            except IOError as err:
+                logging.warning("Failed to read idle state on cpu %s "
+                                "for state %s:\n%s", cpu, state_no, err)
+    return cpu_idlestate
+
+
+def set_cpuidle_state(state_number="all", disable=1, setstate=None):
+    """
+    Set/Reset cpu idle states for all cpus
+
+    :param state_number: cpuidle state number, default: `all` all states
+    :param disable: whether to disable/enable given cpu idle state, default: 1
+    :param setstate: cpuidle state value, output of `get_cpuidle_state()`
+    """
+    cpus_list = cpu_online_list()
+    if not setstate:
+        states = []
+        if state_number == 'all':
+            states = range(0, len(glob.glob("/sys/devices/system/cpu/cpu0/cpuidle/state*")))
+        else:
+            states.append(state_number)
+        for cpu in cpus_list:
+            for state_no in states:
+                state_file = "/sys/devices/system/cpu/cpu%s/cpuidle/state%s/disable" % (cpu, state_no)
+                try:
+                    open(state_file, "w").write(str(disable))
+                except IOError as err:
+                    logging.warning("Failed to set idle state on cpu %s "
+                                    "for state %s:\n%s", cpu, state_no, err)
+    else:
+        for cpu, stateval in setstate.items():
+            for state_no, value in stateval.items():
+                state_file = "/sys/devices/system/cpu/cpu%s/cpuidle/state%s/disable" % (cpu, state_no)
+                try:
+                    open(state_file, "w").write(str(value))
+                except IOError as err:
+                    logging.warning("Failed to set idle state on cpu %s "
+                                    "for state %s:\n%s", cpu, state_no, err)

selftests/unit/test_utils_cpu.py

 import io
 import unittest
+import StringIO
 
 try:
     from unittest import mock
@@ -523,6 +524,54 @@ uarch	: sifive,rocket0
                         return_value=self._get_file_mock(cpu_output)):
             self.assertEqual(cpu.get_cpu_arch(), "riscv")
 
+    @unittest.skipUnless(recent_mock(),
+                         "mock library version cannot (easily) patch open()")
+    def test_get_cpuidle_state_off(self):
+        retval = {0: {0: 0}}
+        with mock.patch('avocado.utils.cpu.cpu_online_list', return_value=[0]):
+            with mock.patch('glob.glob', return_value=['/sys/devices/system/cpu/cpu0/cpuidle/state1']):
+                with mock.patch('avocado.utils.cpu.open', return_value=StringIO.StringIO('0')):
+                    self.assertEqual(cpu.get_cpuidle_state(), retval)
+
+    @unittest.skipUnless(recent_mock(),
+                         "mock library version cannot (easily) patch open()")
+    def test_get_cpuidle_state_on(self):
+        retval = {0: {0: 1}}
+        with mock.patch('avocado.utils.cpu.cpu_online_list', return_value=[0]):
+            with mock.patch('glob.glob', return_value=['/sys/devices/system/cpu/cpu0/cpuidle/state1']):
+                with mock.patch('avocado.utils.cpu.open', return_value=StringIO.StringIO('1')):
+                    self.assertEqual(cpu.get_cpuidle_state(), retval)
+
+    @unittest.skipUnless(recent_mock(),
+                         "mock library version cannot (easily) patch open()")
+    def test_set_cpuidle_state_default(self):
+        output = StringIO.StringIO()
+        with mock.patch('avocado.utils.cpu.cpu_online_list', return_value=[0]):
+            with mock.patch('glob.glob', return_value=['/sys/devices/system/cpu/cpu0/cpuidle/state1']):
+                with mock.patch('avocado.utils.cpu.open', return_value=output):
+                    cpu.set_cpuidle_state()
+                    self.assertEqual(output.getvalue(), "1")
+
+    @unittest.skipUnless(recent_mock(),
+                         "mock library version cannot (easily) patch open()")
+    def test_set_cpuidle_state_withstateno(self):
+        output = StringIO.StringIO()
+        with mock.patch('avocado.utils.cpu.cpu_online_list', return_value=[0]):
+            with mock.patch('glob.glob', return_value=['/sys/devices/system/cpu/cpu0/cpuidle/state2']):
+                with mock.patch('avocado.utils.cpu.open', return_value=output):
+                    cpu.set_cpuidle_state(disable='0', state_number='2')
+                    self.assertEqual(output.getvalue(), "0")
+
+    @unittest.skipUnless(recent_mock(),
+                         "mock library version cannot (easily) patch open()")
+    def test_set_cpuidle_state_withsetstate(self):
+        output = StringIO.StringIO()
+        with mock.patch('avocado.utils.cpu.cpu_online_list', return_value=[0, 2]):
+            with mock.patch('glob.glob', return_value=['/sys/devices/system/cpu/cpu0/cpuidle/state1']):
+                with mock.patch('avocado.utils.cpu.open', return_value=output):
+                    cpu.set_cpuidle_state(setstate={0: {0: 1}, 2: {0: 0}})
+                    self.assertEqual(output.getvalue(), "10")
+
 
 if __name__ == "__main__":
     unittest.main()