DellEMC: Z9264-Platform2.0 Implementation [Reboot Cause] (#4246)

- Added get_reboot_cause() API implementation in chassis.py
- Added new file platform.py for platform2.0 API implementation.

platform/broadcom/sonic-platform-modules-dell/z9264f/scripts/z9264f_platform.sh

@@ -183,6 +183,18 @@ platform_firmware_versions()
     echo "Slave CPLD 4: $((r_maj)).$((r_min))" >> $FIRMWARE_VERSION_FILE
 }
 
+get_reboot_cause() {
+    REBOOT_REASON_FILE="/host/reboot-cause/platform/reboot_reason"
+    resource="/sys/bus/pci/devices/0000:04:00.0/resource0"
+
+    # Handle First Boot into software version with reboot cause determination support
+    if [[ ! -e $REBOOT_REASON_FILE ]]; then
+        echo "0" > $REBOOT_REASON_FILE
+    else
+        /usr/bin/pcisysfs.py --get --offset 0x18 --res $resource | sed '1d; s/.*:\(.*\)$/\1/;' > $REBOOT_REASON_FILE
+    fi
+    /usr/bin/pcisysfs.py --set --val 0x0 --offset 0x18 --res $resource
+}
 
 init_devnum
 
@@ -194,6 +206,7 @@ if [ "$1" == "init" ]; then
     modprobe i2c_ocores
     modprobe dell_z9264f_fpga_ocores
     sys_eeprom "new_device"
+    get_reboot_cause
     switch_board_qsfp_mux "new_device"
     switch_board_qsfp "new_device"
     switch_board_sfp "new_device"

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

@@ -1,3 +1,3 @@
-__all__ = ["chassis", "sfp", "eeprom"]
+__all__ = ["platform", "chassis", "sfp", "eeprom", "component", "psu", "thermal"]
 from sonic_platform import *
 

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

@@ -30,6 +30,7 @@ class Chassis(ChassisBase):
     DELLEMC Platform-specific Chassis class
     """
 
+    REBOOT_CAUSE_PATH = "/host/reboot-cause/platform/reboot_reason"
     OIR_FD_PATH = "/sys/bus/pci/devices/0000:04:00.0/port_msi"
 
     oir_fd = -1
@@ -263,3 +264,40 @@ class Chassis(ChassisBase):
             values.
         """
         return self._eeprom.system_eeprom_info()
+
+    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.
+        """
+        try:
+            with open(self.REBOOT_CAUSE_PATH) as fd:
+                reboot_cause = int(fd.read(), 16)
+        except:
+            return (self.REBOOT_CAUSE_NON_HARDWARE, None)
+
+        if reboot_cause & 0x1:
+            return (self.REBOOT_CAUSE_POWER_LOSS, None)
+        elif reboot_cause & 0x2:
+            return (self.REBOOT_CAUSE_NON_HARDWARE, None)
+        elif reboot_cause & 0x4:
+            return (self.REBOOT_CAUSE_HARDWARE_OTHER, "PSU Shutdown")
+        elif reboot_cause & 0x8:
+            return (self.REBOOT_CAUSE_THERMAL_OVERLOAD_CPU, None)
+        elif reboot_cause & 0x10:
+            return (self.REBOOT_CAUSE_WATCHDOG, None)
+        elif reboot_cause & 0x20:
+            return (self.REBOOT_CAUSE_HARDWARE_OTHER, "BMC Shutdown")
+        elif reboot_cause & 0x40:
+            return (self.REBOOT_CAUSE_HARDWARE_OTHER, "Hot-Swap Shutdown")
+        elif reboot_cause & 0x80:
+            return (self.REBOOT_CAUSE_HARDWARE_OTHER, "Reset Button Shutdown")
+        elif reboot_cause & 0x100:
+            return (self.REBOOT_CAUSE_HARDWARE_OTHER, "Reset Button Cold Reboot")
+        else:
+            return (self.REBOOT_CAUSE_NON_HARDWARE, None)

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

@@ -0,0 +1,24 @@
+#!/usr/bin/env python
+
+#############################################################################
+#
+# Module contains an implementation of SONiC Platform Base API and
+# provides the platform information
+#
+#############################################################################
+
+try:
+    from sonic_platform_base.platform_base import PlatformBase
+    from sonic_platform.chassis import Chassis
+except ImportError as e:
+    raise ImportError(str(e) + "- required module not found")
+
+
+class Platform(PlatformBase):
+    """
+    DELLEMC Platform-specific class
+    """
+
+    def __init__(self):
+        PlatformBase.__init__(self)
+        self._chassis = Chassis()