[device/celestica] Implement Watchdog APIs based on the new platform API (#3123)

device/celestica/x86_64-cel_e1031-r0/sonic_platform/chassis.py

@@ -20,12 +20,15 @@ try:
     from sonic_platform.psu import Psu
     from sonic_platform.device import Device
     from sonic_platform.component import Component
+    from sonic_platform.watchdog import Watchdog
 except ImportError as e:
     raise ImportError(str(e) + "- required module not found")
 
 CONFIG_DB_PATH = "/etc/sonic/config_db.json"
 NUM_FAN = 3
 NUM_PSU = 2
+RESET_REGISTER = "0x112"
+REBOOT_CAUSE_PATH = "/host/reboot-cause/previous-reboot-cause.txt"
 
 
 class Chassis(ChassisBase):
@@ -42,6 +45,7 @@ class Chassis(ChassisBase):
         ChassisBase.__init__(self)
         self._component_device = Device("component")
         self._component_name_list = self._component_device.get_name_list()
+        self._watchdog = Watchdog()
 
     def __read_config_db(self):
         try:
@@ -51,6 +55,14 @@ class Chassis(ChassisBase):
         except IOError:
             raise IOError("Unable to open config_db file !")
 
+    def __read_txt_file(self, file_path):
+        try:
+            with open(file_path, 'r') as fd:
+                data = fd.read()
+                return data.strip()
+        except IOError:
+            raise IOError("Unable to open %s file !" % file_path)
+
     def get_base_mac(self):
         """
         Retrieves the base MAC address for the chassis
@@ -63,7 +75,7 @@ class Chassis(ChassisBase):
             base_mac = self.config_data["DEVICE_METADATA"]["localhost"]["mac"]
             return str(base_mac)
         except KeyError:
-            raise KeyError("Base MAC not found")
+            return str(None)
 
     def get_firmware_version(self, component_name):
         """
@@ -94,3 +106,32 @@ class Chassis(ChassisBase):
         if component_name not in self._component_name_list:
             return False
         return self.component.upgrade_firmware(image_path)
+
+    def get_reboot_cause(self):
+        """
+        Retrieves the cause of the previous reboot
+
+        Returns:
+            A tuple (string, string) where the first element is a string
+            containing the cause of the previous reboot. This string must be
+            one of the predefined strings in this class. If the first string
+            is "REBOOT_CAUSE_HARDWARE_OTHER", the second string can be used
+            to pass a description of the reboot cause.
+        """
+        self.component = Component("SMC_CPLD")
+        description = 'None'
+        reboot_cause = self.REBOOT_CAUSE_HARDWARE_OTHER
+        hw_reboot_cause = self.component.get_register_value(RESET_REGISTER)
+        sw_reboot_cause = self.__read_txt_file(REBOOT_CAUSE_PATH)
+
+        if sw_reboot_cause != "Unexpected reboot":
+            reboot_cause = self.REBOOT_CAUSE_NON_HARDWARE
+        elif hw_reboot_cause == "0x11":
+            reboot_cause = self.REBOOT_CAUSE_POWER_LOSS
+        elif hw_reboot_cause == "0x33" or hw_reboot_cause == "0x55":
+            reboot_cause = self.REBOOT_CAUSE_WATCHDOG
+        else:
+            reboot_cause = self.REBOOT_CAUSE_HARDWARE_OTHER
+            description = 'Unknown reason'
+
+        return (reboot_cause, description)

device/celestica/x86_64-cel_e1031-r0/sonic_platform/component.py

@@ -23,7 +23,7 @@ MMC_CPLD_ADDR = '0x100'
 BIOS_VERSION_PATH = "/sys/class/dmi/id/bios_version"
 CONFIG_DB_PATH = "/etc/sonic/config_db.json"
 SMC_CPLD_PATH = "/sys/devices/platform/e1031.smc/version"
-MMC_CPLD_PATH = "/sys/devices/platform/e1031.smc/getreg"
+GETREG_PATH = "/sys/devices/platform/e1031.smc/getreg"
 
 
 class Component(DeviceBase):
@@ -51,16 +51,6 @@ class Component(DeviceBase):
             return False
         return True
 
-    def __get_register_value(self, path, register):
-        # Retrieves the cpld register value
-        cmd = "echo {1} > {0}; cat {0}".format(path, register)
-        p = subprocess.Popen(
-            cmd, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-        raw_data, err = p.communicate()
-        if err is not '':
-            return None
-        return raw_data.strip()
-
     def __get_bios_version(self):
         # Retrieves the BIOS firmware version
         try:
@@ -70,6 +60,16 @@ class Component(DeviceBase):
         except Exception as e:
             return None
 
+    def get_register_value(self, register):
+        # Retrieves the cpld register value
+        cmd = "echo {1} > {0}; cat {0}".format(GETREG_PATH, register)
+        p = subprocess.Popen(
+            cmd, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        raw_data, err = p.communicate()
+        if err is not '':
+            return None
+        return raw_data.strip()
+
     def __get_cpld_version(self):
         # Retrieves the CPLD firmware version
         cpld_version = dict()
@@ -78,8 +78,7 @@ class Component(DeviceBase):
         smc_cpld_version = 'None' if smc_cpld_version is 'None' else "{}.{}".format(
             int(smc_cpld_version[2], 16), int(smc_cpld_version[3], 16))
 
-        mmc_cpld_version = self.__get_register_value(
+        mmc_cpld_version = self.get_register_value(MMC_CPLD_ADDR)
-            MMC_CPLD_PATH, MMC_CPLD_ADDR)
         mmc_cpld_version = 'None' if mmc_cpld_version is 'None' else "{}.{}".format(
             int(mmc_cpld_version[2], 16), int(mmc_cpld_version[3], 16))
 

device/celestica/x86_64-cel_e1031-r0/sonic_platform/watchdog.py

@@ -0,0 +1,233 @@
+#!/usr/bin/env python
+
+#############################################################################
+# Celestica
+#
+# Watchdog contains an implementation of SONiC Platform Base API
+#
+#############################################################################
+import ctypes
+import fcntl
+import os
+import subprocess
+import time
+import array
+
+try:
+    from sonic_platform_base.watchdog_base import WatchdogBase
+except ImportError as e:
+    raise ImportError(str(e) + "- required module not found")
+
+""" ioctl constants """
+IO_WRITE = 0x40000000
+IO_READ = 0x80000000
+IO_READ_WRITE = 0xC0000000
+IO_SIZE_INT = 0x00040000
+IO_SIZE_40 = 0x00280000
+IO_TYPE_WATCHDOG = ord('W') << 8
+
+WDR_INT = IO_READ | IO_SIZE_INT | IO_TYPE_WATCHDOG
+WDR_40 = IO_READ | IO_SIZE_40 | IO_TYPE_WATCHDOG
+WDWR_INT = IO_READ_WRITE | IO_SIZE_INT | IO_TYPE_WATCHDOG
+
+""" Watchdog ioctl commands """
+WDIOC_GETSUPPORT = 0 | WDR_40
+WDIOC_GETSTATUS = 1 | WDR_INT
+WDIOC_GETBOOTSTATUS = 2 | WDR_INT
+WDIOC_GETTEMP = 3 | WDR_INT
+WDIOC_SETOPTIONS = 4 | WDR_INT
+WDIOC_KEEPALIVE = 5 | WDR_INT
+WDIOC_SETTIMEOUT = 6 | WDWR_INT
+WDIOC_GETTIMEOUT = 7 | WDR_INT
+WDIOC_SETPRETIMEOUT = 8 | WDWR_INT
+WDIOC_GETPRETIMEOUT = 9 | WDR_INT
+WDIOC_GETTIMELEFT = 10 | WDR_INT
+
+""" Watchdog status constants """
+WDIOS_DISABLECARD = 0x0001
+WDIOS_ENABLECARD = 0x0002
+
+WDT_COMMON_ERROR = -1
+WD_MAIN_IDENTITY = "iTCO_wdt"
+WDT_SYSFS_PATH = "/sys/class/watchdog/"
+
+
+class Watchdog(WatchdogBase):
+
+    def __init__(self):
+
+        self.watchdog, self.wdt_main_dev_name = self._get_wdt()
+        self.status_path = "/sys/class/watchdog/%s/status" % self.wdt_main_dev_name
+        self.state_path = "/sys/class/watchdog/%s/state" % self.wdt_main_dev_name
+        self.timeout_path = "/sys/class/watchdog/%s/timeout" % self.wdt_main_dev_name
+        # Set default value
+        self._disable()
+        self.armed = False
+        self.timeout = self._gettimeout(self.timeout_path)
+
+    def _is_wd_main(self, dev):
+        """
+        Checks watchdog identity
+        """
+        identity = self._read_file(
+            "{}/{}/identity".format(WDT_SYSFS_PATH, dev))
+        return identity == WD_MAIN_IDENTITY
+
+    def _get_wdt(self):
+        """
+        Retrieves watchdog device
+        """
+        wdt_main_dev_list = [dev for dev in os.listdir(
+            "/dev/") if dev.startswith("watchdog") and self._is_wd_main(dev)]
+        if not wdt_main_dev_list:
+            return None
+        wdt_main_dev_name = wdt_main_dev_list[0]
+        watchdog_device_path = "/dev/{}".format(wdt_main_dev_name)
+        watchdog = os.open(watchdog_device_path, os.O_RDWR)
+        return watchdog, wdt_main_dev_name
+
+    def _read_file(self, file_path):
+        """
+        Read text file
+        """
+        try:
+            with open(file_path, "r") as fd:
+                txt = fd.read()
+        except IOError:
+            return WDT_COMMON_ERROR
+        return txt.strip()
+
+    def _enable(self):
+        """
+        Turn on the watchdog timer
+        """
+        req = array.array('h', [WDIOS_ENABLECARD])
+        fcntl.ioctl(self.watchdog, WDIOC_SETOPTIONS, req, False)
+
+    def _disable(self):
+        """
+        Turn off the watchdog timer
+        """
+        req = array.array('h', [WDIOS_DISABLECARD])
+        fcntl.ioctl(self.watchdog, WDIOC_SETOPTIONS, req, False)
+
+    def _keepalive(self):
+        """
+        Keep alive watchdog timer
+        """
+        fcntl.ioctl(self.watchdog, WDIOC_KEEPALIVE)
+
+    def _settimeout(self, seconds):
+        """
+        Set watchdog timer timeout
+        @param seconds - timeout in seconds
+        @return is the actual set timeout
+        """
+        req = array.array('I', [seconds])
+        fcntl.ioctl(self.watchdog, WDIOC_SETTIMEOUT, req, True)
+        return int(req[0])
+
+    def _gettimeout(self, timeout_path):
+        """
+        Get watchdog timeout
+        @return watchdog timeout
+        """
+        req = array.array('I', [0])
+        fcntl.ioctl(self.watchdog, WDIOC_GETTIMEOUT, req, True)
+
+        return int(req[0])
+
+    def _gettimeleft(self):
+        """
+        Get time left before watchdog timer expires
+        @return time left in seconds
+        """
+        req = array.array('I', [0])
+        fcntl.ioctl(self.watchdog, WDIOC_GETTIMELEFT, req, True)
+
+        return int(req[0])
+
+    #################################################################
+
+    def arm(self, seconds):
+        """
+        Arm the hardware watchdog with a timeout of <seconds> seconds.
+        If the watchdog is currently armed, calling this function will
+        simply reset the timer to the provided value. If the underlying
+        hardware does not support the value provided in <seconds>, this
+        method should arm the watchdog with the *next greater* available
+        value.
+        Returns:
+            An integer specifying the *actual* number of seconds the watchdog
+            was armed with. On failure returns -1.
+        """
+
+        ret = WDT_COMMON_ERROR
+        if seconds < 0:
+            return ret
+
+        try:
+            if self.timeout != seconds:
+                self.timeout = self._settimeout(seconds)
+            if self.armed:
+                self._keepalive()
+            else:
+                self._enable()
+                self.armed = True
+            ret = self.timeout
+        except IOError as e:
+            pass
+
+        return ret
+
+    def disarm(self):
+        """
+        Disarm the hardware watchdog
+        Returns:
+            A boolean, True if watchdog is disarmed successfully, False if not
+        """
+        disarmed = False
+        if self.is_armed():
+            try:
+                self._disable()
+                self.armed = False
+                disarmed = True
+            except IOError:
+                pass
+
+        return disarmed
+
+    def is_armed(self):
+        """
+        Retrieves the armed state of the hardware watchdog.
+        Returns:
+            A boolean, True if watchdog is armed, False if not
+        """
+
+        return self.armed
+
+    def get_remaining_time(self):
+        """
+        If the watchdog is armed, retrieve the number of seconds remaining on
+        the watchdog timer
+        Returns:
+            An integer specifying the number of seconds remaining on thei
+            watchdog timer. If the watchdog is not armed, returns -1.
+        """
+
+        timeleft = WDT_COMMON_ERROR
+
+        if self.armed:
+            try:
+                timeleft = self._gettimeleft()
+            except IOError:
+                pass
+
+        return timeleft
+
+    def __del__(self):
+        """
+        Close watchdog
+        """
+
+        os.close(self.watchdog)

device/celestica/x86_64-cel_seastone-r0/sonic_platform/chassis.py

@@ -20,12 +20,15 @@ try:
     from sonic_platform.psu import Psu
     from sonic_platform.device import Device
     from sonic_platform.component import Component
+    from sonic_platform.watchdog import Watchdog
 except ImportError as e:
     raise ImportError(str(e) + "- required module not found")
 
 CONFIG_DB_PATH = "/etc/sonic/config_db.json"
 NUM_FAN = 5
 NUM_PSU = 2
+RESET_REGISTER = "0x103"
+REBOOT_CAUSE_PATH = "/host/reboot-cause/previous-reboot-cause.txt"
 
 
 class Chassis(ChassisBase):
@@ -42,6 +45,7 @@ class Chassis(ChassisBase):
         ChassisBase.__init__(self)
         self._component_device = Device("component")
         self._component_name_list = self._component_device.get_name_list()
+        self._watchdog = Watchdog()
 
     def __read_config_db(self):
         try:
@@ -51,6 +55,14 @@ class Chassis(ChassisBase):
         except IOError:
             raise IOError("Unable to open config_db file !")
 
+    def __read_txt_file(self, file_path):
+        try:
+            with open(file_path, 'r') as fd:
+                data = fd.read()
+                return data.strip()
+        except IOError:
+            raise IOError("Unable to open %s file !" % file_path)
+
     def get_base_mac(self):
         """
         Retrieves the base MAC address for the chassis
@@ -63,7 +75,7 @@ class Chassis(ChassisBase):
             base_mac = self.config_data["DEVICE_METADATA"]["localhost"]["mac"]
             return str(base_mac)
         except KeyError:
-            raise KeyError("Base MAC not found")
+            return str(None)
 
     def get_firmware_version(self, component_name):
         """
@@ -94,3 +106,33 @@ class Chassis(ChassisBase):
         if component_name not in self._component_name_list:
             return False
         return self.component.upgrade_firmware(image_path)
+
+    def get_reboot_cause(self):
+        """
+        Retrieves the cause of the previous reboot
+
+        Returns:
+            A tuple (string, string) where the first element is a string
+            containing the cause of the previous reboot. This string must be
+            one of the predefined strings in this class. If the first string
+            is "REBOOT_CAUSE_HARDWARE_OTHER", the second string can be used
+            to pass a description of the reboot cause.
+        """
+        self.component = Component("CPLD1")
+        description = 'None'
+        reboot_cause = self.REBOOT_CAUSE_HARDWARE_OTHER
+        hw_reboot_cause = self.component.get_register_value(RESET_REGISTER)
+        sw_reboot_cause = self.__read_txt_file(REBOOT_CAUSE_PATH)
+
+        if sw_reboot_cause != "Unexpected reboot":
+            reboot_cause = self.REBOOT_CAUSE_NON_HARDWARE
+            description = sw_reboot_cause
+        elif hw_reboot_cause == "0x11":
+            reboot_cause = self.REBOOT_CAUSE_POWER_LOSS
+        elif hw_reboot_cause == "0x22":
+            reboot_cause = self.REBOOT_CAUSE_WATCHDOG,
+        else:
+            reboot_cause = self.REBOOT_CAUSE_HARDWARE_OTHER
+            description = 'Unknown reason'
+
+        return (reboot_cause, description)

device/celestica/x86_64-cel_seastone-r0/sonic_platform/component.py

@@ -55,16 +55,6 @@ class Component(DeviceBase):
             return False
         return True
 
-    def __get_register_value(self, path, register):
-        # Retrieves the cpld register value
-        cmd = "echo {1} > {0}; cat {0}".format(path, register)
-        p = subprocess.Popen(
-            cmd, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-        raw_data, err = p.communicate()
-        if err is not '':
-            return None
-        return raw_data.strip()
-
     def __get_bios_version(self):
         # Retrieves the BIOS firmware version
         try:
@@ -74,14 +64,23 @@ class Component(DeviceBase):
         except Exception as e:
             return None
 
+    def get_register_value(self, register):
+        # Retrieves the cpld register value
+        cmd = "echo {1} > {0}; cat {0}".format(GETREG_PATH, register)
+        p = subprocess.Popen(
+            cmd, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        raw_data, err = p.communicate()
+        if err is not '':
+            return None
+        return raw_data.strip()
+
     def __get_cpld_version(self):
         # Retrieves the CPLD firmware version
         cpld_version = dict()
         for cpld_name in CPLD_ADDR_MAPPING:
             try:
                 cpld_addr = CPLD_ADDR_MAPPING[cpld_name]
-                cpld_version_raw = self.__get_register_value(
+                cpld_version_raw = self.get_register_value(cpld_addr)
-                    GETREG_PATH, cpld_addr)
                 cpld_version_str = "{}.{}".format(int(cpld_version_raw[2], 16), int(
                     cpld_version_raw[3], 16)) if cpld_version_raw is not None else 'None'
                 cpld_version[cpld_name] = cpld_version_str

device/celestica/x86_64-cel_seastone-r0/sonic_platform/watchdog.py

@@ -0,0 +1,233 @@
+#!/usr/bin/env python
+
+#############################################################################
+# Celestica
+#
+# Watchdog contains an implementation of SONiC Platform Base API
+#
+#############################################################################
+import ctypes
+import fcntl
+import os
+import subprocess
+import time
+import array
+
+try:
+    from sonic_platform_base.watchdog_base import WatchdogBase
+except ImportError as e:
+    raise ImportError(str(e) + "- required module not found")
+
+""" ioctl constants """
+IO_WRITE = 0x40000000
+IO_READ = 0x80000000
+IO_READ_WRITE = 0xC0000000
+IO_SIZE_INT = 0x00040000
+IO_SIZE_40 = 0x00280000
+IO_TYPE_WATCHDOG = ord('W') << 8
+
+WDR_INT = IO_READ | IO_SIZE_INT | IO_TYPE_WATCHDOG
+WDR_40 = IO_READ | IO_SIZE_40 | IO_TYPE_WATCHDOG
+WDWR_INT = IO_READ_WRITE | IO_SIZE_INT | IO_TYPE_WATCHDOG
+
+""" Watchdog ioctl commands """
+WDIOC_GETSUPPORT = 0 | WDR_40
+WDIOC_GETSTATUS = 1 | WDR_INT
+WDIOC_GETBOOTSTATUS = 2 | WDR_INT
+WDIOC_GETTEMP = 3 | WDR_INT
+WDIOC_SETOPTIONS = 4 | WDR_INT
+WDIOC_KEEPALIVE = 5 | WDR_INT
+WDIOC_SETTIMEOUT = 6 | WDWR_INT
+WDIOC_GETTIMEOUT = 7 | WDR_INT
+WDIOC_SETPRETIMEOUT = 8 | WDWR_INT
+WDIOC_GETPRETIMEOUT = 9 | WDR_INT
+WDIOC_GETTIMELEFT = 10 | WDR_INT
+
+""" Watchdog status constants """
+WDIOS_DISABLECARD = 0x0001
+WDIOS_ENABLECARD = 0x0002
+
+WDT_COMMON_ERROR = -1
+WD_MAIN_IDENTITY = "iTCO_wdt"
+WDT_SYSFS_PATH = "/sys/class/watchdog/"
+
+
+class Watchdog(WatchdogBase):
+
+    def __init__(self):
+
+        self.watchdog, self.wdt_main_dev_name = self._get_wdt()
+        self.status_path = "/sys/class/watchdog/%s/status" % self.wdt_main_dev_name
+        self.state_path = "/sys/class/watchdog/%s/state" % self.wdt_main_dev_name
+        self.timeout_path = "/sys/class/watchdog/%s/timeout" % self.wdt_main_dev_name
+        # Set default value
+        self._disable()
+        self.armed = False
+        self.timeout = self._gettimeout(self.timeout_path)
+
+    def _is_wd_main(self, dev):
+        """
+        Checks watchdog identity
+        """
+        identity = self._read_file(
+            "{}/{}/identity".format(WDT_SYSFS_PATH, dev))
+        return identity == WD_MAIN_IDENTITY
+
+    def _get_wdt(self):
+        """
+        Retrieves watchdog device
+        """
+        wdt_main_dev_list = [dev for dev in os.listdir(
+            "/dev/") if dev.startswith("watchdog") and self._is_wd_main(dev)]
+        if not wdt_main_dev_list:
+            return None
+        wdt_main_dev_name = wdt_main_dev_list[0]
+        watchdog_device_path = "/dev/{}".format(wdt_main_dev_name)
+        watchdog = os.open(watchdog_device_path, os.O_RDWR)
+        return watchdog, wdt_main_dev_name
+
+    def _read_file(self, file_path):
+        """
+        Read text file
+        """
+        try:
+            with open(file_path, "r") as fd:
+                txt = fd.read()
+        except IOError:
+            return WDT_COMMON_ERROR
+        return txt.strip()
+
+    def _enable(self):
+        """
+        Turn on the watchdog timer
+        """
+        req = array.array('h', [WDIOS_ENABLECARD])
+        fcntl.ioctl(self.watchdog, WDIOC_SETOPTIONS, req, False)
+
+    def _disable(self):
+        """
+        Turn off the watchdog timer
+        """
+        req = array.array('h', [WDIOS_DISABLECARD])
+        fcntl.ioctl(self.watchdog, WDIOC_SETOPTIONS, req, False)
+
+    def _keepalive(self):
+        """
+        Keep alive watchdog timer
+        """
+        fcntl.ioctl(self.watchdog, WDIOC_KEEPALIVE)
+
+    def _settimeout(self, seconds):
+        """
+        Set watchdog timer timeout
+        @param seconds - timeout in seconds
+        @return is the actual set timeout
+        """
+        req = array.array('I', [seconds])
+        fcntl.ioctl(self.watchdog, WDIOC_SETTIMEOUT, req, True)
+        return int(req[0])
+
+    def _gettimeout(self, timeout_path):
+        """
+        Get watchdog timeout
+        @return watchdog timeout
+        """
+        req = array.array('I', [0])
+        fcntl.ioctl(self.watchdog, WDIOC_GETTIMEOUT, req, True)
+
+        return int(req[0])
+
+    def _gettimeleft(self):
+        """
+        Get time left before watchdog timer expires
+        @return time left in seconds
+        """
+        req = array.array('I', [0])
+        fcntl.ioctl(self.watchdog, WDIOC_GETTIMELEFT, req, True)
+
+        return int(req[0])
+
+    #################################################################
+
+    def arm(self, seconds):
+        """
+        Arm the hardware watchdog with a timeout of <seconds> seconds.
+        If the watchdog is currently armed, calling this function will
+        simply reset the timer to the provided value. If the underlying
+        hardware does not support the value provided in <seconds>, this
+        method should arm the watchdog with the *next greater* available
+        value.
+        Returns:
+            An integer specifying the *actual* number of seconds the watchdog
+            was armed with. On failure returns -1.
+        """
+
+        ret = WDT_COMMON_ERROR
+        if seconds < 0:
+            return ret
+
+        try:
+            if self.timeout != seconds:
+                self.timeout = self._settimeout(seconds)
+            if self.armed:
+                self._keepalive()
+            else:
+                self._enable()
+                self.armed = True
+            ret = self.timeout
+        except IOError as e:
+            pass
+
+        return ret
+
+    def disarm(self):
+        """
+        Disarm the hardware watchdog
+        Returns:
+            A boolean, True if watchdog is disarmed successfully, False if not
+        """
+        disarmed = False
+        if self.is_armed():
+            try:
+                self._disable()
+                self.armed = False
+                disarmed = True
+            except IOError:
+                pass
+
+        return disarmed
+
+    def is_armed(self):
+        """
+        Retrieves the armed state of the hardware watchdog.
+        Returns:
+            A boolean, True if watchdog is armed, False if not
+        """
+
+        return self.armed
+
+    def get_remaining_time(self):
+        """
+        If the watchdog is armed, retrieve the number of seconds remaining on
+        the watchdog timer
+        Returns:
+            An integer specifying the number of seconds remaining on thei
+            watchdog timer. If the watchdog is not armed, returns -1.
+        """
+
+        timeleft = WDT_COMMON_ERROR
+
+        if self.armed:
+            try:
+                timeleft = self._gettimeleft()
+            except IOError:
+                pass
+
+        return timeleft
+
+    def __del__(self):
+        """
+        Close watchdog
+        """
+
+        os.close(self.watchdog)