[mellanox] Implement Watchdog API based on the new platform API (#2607)

Signed-off-by: Stepan Blyschak <stepanb@mellanox.com>

platform/mellanox/mlnx-platform-api/sonic_platform_api/chassis.py

@@ -13,6 +13,7 @@ import sys
 try:
     from sonic_platform_base.chassis_base import ChassisBase
     from sonic_platform_api.psu import Psu
+    from sonic_platform_api.watchdog import get_watchdog
 except ImportError as e:
     raise ImportError (str(e) + "- required module not found")
 
@@ -20,9 +21,15 @@ MLNX_NUM_PSU = 2
 
 class Chassis(ChassisBase):
     """Platform-specific Chassis class"""
+
     def __init__(self):
         ChassisBase.__init__(self)
+
+        # Initialize PSU list
         for index in range(MLNX_NUM_PSU):
             psu = Psu(index)
             self._psu_list.append(psu)
 
+        # Initialize watchdog
+        self._watchdog = get_watchdog()
+

platform/mellanox/mlnx-platform-api/sonic_platform_api/watchdog.py

@@ -0,0 +1,288 @@
+#!/usr/bin/env python
+
+"""
+Mellanox
+
+Module contains an implementation of SONiC Platform Base API and
+provides access to hardware watchdog on Mellanox platforms
+"""
+
+import os
+import fcntl
+import array
+import time
+
+from sonic_platform_base.watchdog_base import WatchdogBase
+
+""" 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
+
+""" Mellanox main watchdog identity string """
+WD_MLNX_MAIN_IDENTITY = "mlx-wdt-main"
+""" watchdog sysfs """
+WD_SYSFS_PATH = "/sys/class/watchdog/"
+
+
+WD_COMMON_ERROR = -1
+
+
+class WatchdogImplBase(WatchdogBase):
+    """
+    Base class that implements common logic for interacting
+    with watchdog using ioctl commands
+    """
+
+    def __init__(self, wd_device_path):
+        """
+        Open a watchdog handle
+        @param wd_device_path Path to watchdog device
+        """
+
+        self.watchdog_path = wd_device_path
+        self.watchdog = os.open(self.watchdog_path, os.O_WRONLY)
+
+        # Opening a watchdog descriptor starts
+        # watchdog timer;
+        # by default it should be stopped
+        self._disablecard()
+        self.armed = False
+
+        self.timeout = self._gettimeout()
+
+    def _enablecard(self):
+        """
+        Turn on the watchdog timer
+        """
+
+        req = array.array('h', [WDIOS_ENABLECARD])
+        fcntl.ioctl(self.watchdog, WDIOC_SETOPTIONS, req, False)
+
+    def _disablecard(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):
+        """
+        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):
+        """
+        Implements arm WatchdogBase API
+        """
+
+        ret = WD_COMMON_ERROR
+        if seconds < 0:
+            return ret
+
+        try:
+            if self.timeout != seconds:
+                self.timeout = self._settimeout(seconds)
+            if self.armed:
+                self._keepalive()
+            else:
+                self._enablecard()
+                self.armed = True
+            ret = self.timeout
+        except IOError:
+            pass
+
+        return ret
+
+    def disarm(self):
+        """
+        Implements disarm WatchdogBase API
+        """
+
+        disarmed = False
+        if self.armed:
+            try:
+                self._disablecard()
+                self.armed = False
+                disarmed = True
+            except IOError:
+                pass
+
+        return disarmed
+
+    def is_armed(self):
+        """
+        Implements is_armed WatchdogBase API
+        """
+
+        return self.armed
+
+    def get_remaining_time(self):
+        """
+        Implements get_remaining_time WatchdogBase API
+        """
+
+        timeleft = WD_COMMON_ERROR
+
+        if self.armed:
+            try:
+                timeleft = self._gettimeleft()
+            except IOError:
+                pass
+
+        return timeleft
+
+    def __del__(self):
+        """
+        Close watchdog
+        """
+
+        os.close(self.watchdog)
+
+
+class WatchdogType1(WatchdogImplBase):
+    """
+    Watchdog type 1
+    """
+
+    def arm(self, seconds):
+        """
+        Call arm from WatchdgoImplBase and save the timestamp
+        when the watchdog was armed
+        """
+
+        ret = WatchdogImplBase.arm(self, seconds)
+        # Save the watchdog arm timestamp
+        # requiered for get_remaining_time()
+        self.arm_timestamp = time.time()
+
+        return ret
+
+    def get_remaining_time(self):
+        """
+        Watchdog Type 1 does not support timeleft
+        operation, we will calculate timeleft based
+        on timeout and arm timestamp
+        """
+
+        timeleft = WD_COMMON_ERROR
+
+        if self.armed:
+            timeleft = int(self.timeout - (time.time() - self.arm_timestamp))
+
+        return timeleft
+
+class WatchdogType2(WatchdogImplBase):
+    """
+    Watchdog type 2
+    """
+
+    pass
+
+
+def is_mlnx_wd_main(dev):
+    """
+    Checks if dev is Mellanox main watchdog
+    """
+
+    try:
+        with open("{}/{}/identity".format(WD_SYSFS_PATH, dev)) as identity_file:
+            identity = identity_file.read().strip()
+            if identity == WD_MLNX_MAIN_IDENTITY:
+                return True
+    except IOError:
+        pass
+
+    return False
+
+
+def is_wd_type2(dev):
+    """
+    Checks if dev is Mellanox type 2 watchdog
+    """
+
+    return os.path.exists("{}/{}/timeleft".format(WD_SYSFS_PATH, dev))
+
+
+def get_watchdog():
+    """
+    Return WatchdogType1 or WatchdogType2 based on system
+    """
+
+    watchdog_main_device_name = None
+
+    for device in os.listdir("/dev/"):
+        if device.startswith("watchdog") and is_mlnx_wd_main(device):
+            watchdog_main_device_name = device
+
+    watchdog_device_path = "/dev/{}".format(watchdog_main_device_name)
+
+    watchdog = None
+
+    if is_wd_type2(watchdog_main_device_name):
+        watchdog = WatchdogType2(watchdog_device_path)
+    else:
+        watchdog = WatchdogType1(watchdog_device_path)
+
+    return watchdog