[DellEMC] Z9264f Watchdog support (#4192)

Co-authored-by: Sujin Kang <sujkang@microsoft.com>

platform/broadcom/sonic-platform-modules-dell/z9264f/sonic_platform/chassis.py

@@ -16,6 +16,7 @@ try:
     from sonic_platform.eeprom import Eeprom
     from sonic_platform.component import Component
     from sonic_platform.psu import Psu
+    from sonic_platform.watchdog import Watchdog
     from sonic_platform.fan import Fan
     from sonic_platform.thermal import Thermal
 except ImportError as e:
@@ -62,6 +63,8 @@ class Chassis(ChassisBase):
 
         self._eeprom = Eeprom()
 
+        self._watchdog = Watchdog()
+        
         for i in range(MAX_Z9264F_COMPONENT):
             component = Component(i)
             self._component_list.append(component)

platform/broadcom/sonic-platform-modules-dell/z9264f/sonic_platform/watchdog.py

@@ -0,0 +1,214 @@
+#!/usr/bin/env python
+
+########################################################################
+#
+# DELLEMC Z9264f
+#
+# Abstract base class for implementing a platform-specific class with
+# which to interact with a hardware watchdog module in SONiC
+#
+########################################################################
+
+try:
+    import sys
+    import struct
+    import ctypes
+    import subprocess
+    from sonic_platform_base.watchdog_base import WatchdogBase
+except ImportError as e:
+    raise ImportError(str(e) + "- required module not found")
+
+
+class _timespec(ctypes.Structure):
+    _fields_ = [
+            ('tv_sec', ctypes.c_long),
+            ('tv_nsec', ctypes.c_long)
+    ]
+
+
+class Watchdog(WatchdogBase):
+    """
+    Abstract base class for interfacing with a hardware watchdog module
+    """
+
+    TIMERS = [15,20,30,40,50,60,65,70]
+
+    armed_time = 0
+    timeout = 0
+    CLOCK_MONOTONIC = 1
+
+    def __init__(self):
+        self._librt = ctypes.CDLL('librt.so.1', use_errno=True)
+        self._clock_gettime = self._librt.clock_gettime
+        self._clock_gettime.argtypes=[ctypes.c_int, ctypes.POINTER(_timespec)]
+
+    def _get_command_result(self, cmdline):
+        try:
+            proc = subprocess.Popen(cmdline.split(), stdout=subprocess.PIPE,
+                    stderr=subprocess.STDOUT)
+            stdout = proc.communicate()[0]
+            proc.wait()
+            result = stdout.rstrip('\n')
+        except OSError:
+            result = None
+
+        return result
+
+    def _get_reg_val(self):
+        # 0x31 = CPLD I2C Base Address
+        # 0x07 = Watchdog Function Register
+        value = self._get_command_result("/usr/sbin/i2cget -y 601 0x31 0x07")
+        if not value:
+            return None
+        else:
+            return int(value, 16)
+
+    def _set_reg_val(self,val):
+        # 0x31 = CPLD I2C Base Address
+        # 0x07 = Watchdog Function Register
+        value = self._get_command_result("/usr/sbin/i2cset -y 601 0x31 0x07 %s"
+                % (val))
+        return value
+
+    def _get_time(self):
+        """
+        To get clock monotonic time
+        """
+        ts = _timespec()
+        if self._clock_gettime(self.CLOCK_MONOTONIC, ctypes.pointer(ts)) != 0:
+            self._errno = ctypes.get_errno()
+            return 0
+        return ts.tv_sec + ts.tv_nsec * 1e-9
+
+    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.
+        """
+        timer_offset = -1
+        for key,timer_seconds in enumerate(self.TIMERS):
+            if seconds <= timer_seconds:
+                timer_offset = key
+                seconds = timer_seconds
+                break
+
+        if timer_offset == -1:
+            return -1
+
+        # Extracting 5th to 7th bits for WD timer values
+        # 000 - 15 sec
+        # 001 - 20 sec
+        # 010 - 30 sec
+        # 011 - 40 sec
+        # 100 - 50 sec
+        # 101 - 60 sec
+        # 110 - 65 sec
+        # 111 - 70 sec
+        reg_val = self._get_reg_val()
+        wd_timer_offset = (reg_val >> 4) & 0x7
+
+        if wd_timer_offset != timer_offset:
+            # Setting 5th to 7th bits
+            # value from timer_offset
+            self.disarm()
+            self._set_reg_val((reg_val & 0x87) | (timer_offset << 4))
+
+        if self.is_armed():
+            # Setting last bit to WD Timer punch
+            # Last bit = WD Timer punch
+            self._set_reg_val(reg_val & 0xFE)
+
+            self.armed_time = self._get_time()
+            self.timeout = seconds
+            return seconds
+        else:
+            # Setting 4th bit to enable WD
+            # 4th bit = Enable WD
+            reg_val = self._get_reg_val()
+            self._set_reg_val(reg_val | 0x8)
+
+            self.armed_time = self._get_time()
+            self.timeout = seconds
+            return seconds
+
+        return -1
+
+    def disarm(self):
+        """
+        Disarm the hardware watchdog
+
+        Returns:
+            A boolean, True if watchdog is disarmed successfully, False
+            if not
+        """
+        if self.is_armed():
+            # Setting 4th bit to disable WD
+            # 4th bit = Disable WD
+            reg_val = self._get_reg_val()
+            self._set_reg_val(reg_val & 0xF7)
+
+            self.armed_time = 0
+            self.timeout = 0
+            return True
+
+        return False
+
+    def is_armed(self):
+        """
+        Retrieves the armed state of the hardware watchdog.
+
+        Returns:
+            A boolean, True if watchdog is armed, False if not
+        """
+
+        # Extracting 4th bit to get WD Enable/Disable status
+        # 0 - Disabled WD
+        # 1 - Enabled WD
+        reg_val = self._get_reg_val()
+        wd_offset = (reg_val >> 3) & 1
+
+        return bool(wd_offset)
+
+    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
+            their watchdog timer. If the watchdog is not armed, returns
+            -1.
+
+            Z9264 doesnot have hardware support to show remaining time.
+            Due to this limitation, this API is implemented in software.
+            This API would return correct software time difference if it
+            is called from the process which armed the watchdog timer.
+            If this API called from any other process, it would return
+            0. If the watchdog is not armed, this API would return -1.
+        """
+        if not self.is_armed():
+            return -1
+
+        if self.armed_time > 0 and self.timeout != 0:
+            cur_time = self._get_time()
+
+            if cur_time <= 0:
+                return 0
+
+            diff_time = int(cur_time - self.armed_time)
+
+            if diff_time > self.timeout:
+                return self.timeout
+            else:
+                return self.timeout - diff_time
+
+        return 0
+