[DellEMC] S6100 Reboot cause determining CPU reset in fast-reboot (#8024)

Why I did it
Added a check in determining CPU reset in fast-/warm-reboot in their respective platform plugin.
Introducing reboot plugin for "reboot" command to handle its own platform plugin.
How I did it
On branch s6100_fast_warm_check
Changes to be committed:
(use "git reset HEAD ..." to unstage)

    modified:   ../../debian/platform-modules-s6100.install
    modified:   ../scripts/fast-reboot_plugin
    modified:   ../scripts/platform_reboot_override
    new file:   ../scripts/reboot_plugin
    modified:   ../scripts/track_reboot_reason.sh
    modified:   chassis.py
How to verify it
Triggered cold-reset inside fast-reboot to test out the reboot-cause 2.0 API.

platform/broadcom/sonic-platform-modules-dell/debian/platform-modules-s6100.install

@@ -10,6 +10,7 @@ s6100/scripts/platform_reboot_override usr/share/sonic/device/x86_64-dell_s6100_
 s6100/scripts/fast-reboot_plugin usr/share/sonic/device/x86_64-dell_s6100_c2538-r0
 s6100/scripts/track_reboot_reason.sh usr/share/sonic/device/x86_64-dell_s6100_c2538-r0
 s6100/scripts/warm-reboot_plugin usr/share/sonic/device/x86_64-dell_s6100_c2538-r0
+s6100/scripts/reboot_plugin usr/share/sonic/device/x86_64-dell_s6100_c2538-r0
 s6100/scripts/ssd-fw-upgrade usr/share/sonic/device/x86_64-dell_s6100_c2538-r0
 s6100/scripts/override.conf /etc/systemd/system/systemd-reboot.service.d
 common/dell_lpc_mon.sh usr/local/bin

platform/broadcom/sonic-platform-modules-dell/s6100/scripts/fast-reboot_plugin

@@ -4,4 +4,8 @@ if [[ -d /sys/devices/platform/SMF.512/hwmon/ ]]; then
     cd /sys/devices/platform/SMF.512/hwmon/*
     echo 0xcc > mb_poweron_reason
 fi
+
+io_rd_wr.py --set --val 40 --offset 0x131
+io_rd_wr.py --set --val 06 --offset 210; io_rd_wr.py --set --val 0B --offset 211; io_rd_wr.py --set --val aa --offset 213
+
 /usr/local/bin/s6100_i2c_enumeration.sh deinit & > /dev/null

platform/broadcom/sonic-platform-modules-dell/s6100/scripts/platform_reboot_override

@@ -7,8 +7,8 @@ PORT_RES = '/dev/port'
 
 
 def log_software_reboot():
-    # Run plugin script which will track the cli triggered reboot, fastboot, warmboot
+    # Run plugin script which will track the cli triggered reboot
-    res = subprocess.check_output(['/usr/share/sonic/device/x86_64-dell_s6100_c2538-r0/fast-reboot_plugin'])
+    res = subprocess.check_output(['/usr/share/sonic/device/x86_64-dell_s6100_c2538-r0/reboot_plugin'])
     return
 
 def ssd_hdparm_upgrade():

platform/broadcom/sonic-platform-modules-dell/s6100/scripts/reboot_plugin

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+if [[ -d /sys/devices/platform/SMF.512/hwmon/ ]]; then
+    cd /sys/devices/platform/SMF.512/hwmon/*
+    echo 0xcc > mb_poweron_reason
+fi
+
+/usr/local/bin/s6100_i2c_enumeration.sh deinit & > /dev/null

platform/broadcom/sonic-platform-modules-dell/s6100/scripts/track_reboot_reason.sh

@@ -131,7 +131,29 @@ _is_unknown_reset(){
         mb_poweron_reason=$(cat $MAILBOX_POWERON_REASON)
         echo "Unknown POR: $curr_poweron_reason RST: $curr_reset_reason MBR: $mb_poweron_reason" > $REBOOT_CAUSE_FILE
     fi
-    
+
+}
+
+_is_software_reboot(){
+    SMF_STATUS=`io_rd_wr.py --set --val 06 --offset 210; io_rd_wr.py --set --val 0B --offset 211; io_rd_wr.py --get --offset 212`
+    SMF_STATUS=$(echo "$SMF_STATUS" | awk '{print $NF}')
+
+    CPLD_STATUS=`io_rd_wr.py --get --offset 0x131`
+    CPLD_STATUS=$(echo "$CPLD_STATUS" | awk '{print $NF}')
+
+    if [[ $SMF_STATUS == "aa" ]]; then
+        if [[ $CPLD_STATUS != "40" ]]; then
+            # Cold reset happened; Resetting the registers
+            io_rd_wr.py --set --val ff --offset 0x131
+            io_rd_wr.py --set --val 06 --offset 210; io_rd_wr.py --set --val 0B --offset 211; io_rd_wr.py --set --val ff --offset 213
+            echo 0x88 > $MAILBOX_POWERON_REASON
+        else
+            io_rd_wr.py --set --val 06 --offset 210; io_rd_wr.py --set --val 0B --offset 211; io_rd_wr.py --set --val ff --offset 213
+            echo 0xaa > $MAILBOX_POWERON_REASON
+        fi
+    else
+        echo 0xaa > $MAILBOX_POWERON_REASON
+    fi
 }
 
 update_mailbox_register(){
@@ -162,7 +184,7 @@ update_mailbox_register(){
            && [[ $SMF_FPGA_VERSION_MAJOR -ge 1 ]] && [[ $SMF_FPGA_VERSION_MINOR -ge 4 ]]; then
 
             if [[ $reason = "cc" ]]; then
-                echo 0xaa > $MAILBOX_POWERON_REASON
+                _is_software_reboot
             elif [[ $SMF_RESET = "11" ]]; then
                 echo 0xee > $MAILBOX_POWERON_REASON
             elif [[ $SMF_RESET = "33" ]]; then
@@ -185,7 +207,7 @@ update_mailbox_register(){
             elif [[ $is_wd_reboot = 1 ]] && [[ $reason != "cc" ]]; then
                 echo 0xdd > $MAILBOX_POWERON_REASON
             elif [[ $reason = "cc" ]]; then
-                echo 0xaa > $MAILBOX_POWERON_REASON
+                _is_software_reboot
             else
                 _is_unknown_reset $is_thermal_reboot
                 echo 0x99 > $MAILBOX_POWERON_REASON

platform/broadcom/sonic-platform-modules-dell/s6100/sonic_platform/chassis.py

@@ -99,6 +99,7 @@ class Chassis(ChassisBase):
     def _get_reboot_reason_smf_register(self):
         # In S6100, mb_poweron_reason register will
         # Returns 0xaa or 0xcc on software reload
+        # Returns 0x88 on cold-reboot happened during software reload
         # Returns 0xff or 0xbb on power-cycle
         # Returns 0xdd on Watchdog
         # Returns 0xee on Thermal Shutdown
@@ -257,6 +258,8 @@ class Chassis(ChassisBase):
             return (ChassisBase.REBOOT_CAUSE_POWER_LOSS, None)
         elif ((smf_mb_reg_reason == 0xaa) or (smf_mb_reg_reason == 0xcc)):
             return (ChassisBase.REBOOT_CAUSE_NON_HARDWARE, None)
+        elif (smf_mb_reg_reason == 0x88):
+            return (ChassisBase.REBOOT_CAUSE_HARDWARE_OTHER, "CPU Reset")
         elif (smf_mb_reg_reason == 0xdd):
             return (ChassisBase.REBOOT_CAUSE_WATCHDOG, None)
         elif (smf_mb_reg_reason == 0xee):