[Mellanox] Add phcsync script for ASIC clock synchronization (#24972)

- Why I did it
Fix a bug in HFT where the asic clock was not synchronized with the system clock, causing it to report a time around 1970.

There is a dependency between this PR and: sonic-net/sonic-sairedis#1734
The PR to sonic-buildimage should be merged first, followed by the PR to sonic-sairedis.

- How I did it
Added phcsync script for ASIC clock synchronization on Mellanox platforms: created phcsync.sh that syncs PTP clocks with system clock every 60 seconds.

- How to verify it
Which release branch to backport (provide reason below if selected)


Signed-off-by: Zili Bombach <[email protected]>

* Added error logs to phcsync.sh and made phcsync.sh executable

Signed-off-by: Zili Bombach <[email protected]>

---------

Signed-off-by: Zili Bombach <[email protected]>
Co-authored-by: Liat Grozovik <[email protected]>

Author: zili11720

platform/mellanox/docker-syncd-mlnx/Dockerfile.j2

@@ -1,6 +1,6 @@
 ##
 ## SPDX-FileCopyrightText: NVIDIA CORPORATION & AFFILIATES
-## Copyright (c) 2016-2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+## Copyright (c) 2016-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 ## SPDX-License-Identifier: Apache-2.0
 ##
 ## Licensed under the Apache License, Version 2.0 (the "License");
@@ -38,7 +38,8 @@ RUN apt-get update && \
         python3-dev \
         python3-jsonschema \
         python-is-python3 \
-        pciutils
+        pciutils \
+        linuxptp
 
 RUN pip3 install --upgrade pip
 RUN apt-get purge -y python-pip
@@ -67,6 +68,7 @@ RUN apt-get purge -y         \
 COPY ["supervisord.conf.j2", "/usr/share/sonic/templates/"]
 COPY ["critical_processes", "/etc/supervisor/"]
 COPY ["platform_syncd_dump.sh", "/usr/bin/"]
+COPY ["phcsync.sh", "/usr/bin/"]
 
 COPY ["files/rdb-cli", "/usr/bin/"]
 RUN chmod +x /usr/bin/rdb-cli

platform/mellanox/docker-syncd-mlnx/phcsync.sh

@@ -0,0 +1,71 @@
+#!/bin/bash
+#
+# SPDX-FileCopyrightText: NVIDIA CORPORATION & AFFILIATES
+# Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+#
+# Script to synchronize ASIC PTP clocks with system realtime clock.
+# This script runs continuously, syncing clocks every 60 seconds.
+# This script shall not be running if PTP is enabled in the system.
+#
+
+PHC_CTL="/usr/sbin/phc_ctl"
+SLEEP_INTERVAL=60
+
+# Check if phc_ctl is available
+if [ ! -x "$PHC_CTL" ]; then
+    echo "Error: phc_ctl not found. Exiting."
+    exit 1
+fi
+
+while :; do
+    # Refresh the list of PTP devices on each iteration
+    PTP_DEVICES=$(ls /dev/ptp[0-9]* 2>/dev/null)
+    
+    if [ -z "$PTP_DEVICES" ]; then
+        sleep $SLEEP_INTERVAL
+        continue
+    fi
+    
+    for dev in $PTP_DEVICES; do
+        # Extract device number from /dev/ptpXX
+        dev_num=${dev##*/ptp}
+
+        clock_name_file="/sys/class/ptp/ptp${dev_num}/clock_name"
+        if [[ ! -f "$clock_name_file" ]]; then
+            echo "Error: clock_name file not found for $dev ($clock_name_file), skipping" >&2
+            continue
+        fi
+        
+        clock_name=$(cat "$clock_name_file" 2>/dev/null)
+        CLOCK_NAME_EXIT_CODE=$?
+        if [[ $CLOCK_NAME_EXIT_CODE -ne 0 ]] || [[ -z "$clock_name" ]]; then
+            echo "Error: Failed to read clock_name from $clock_name_file for $dev, skipping" >&2
+            continue
+        fi
+        
+        if [[ "$clock_name" != "mlx5_ptp" ]]; then
+            # set CLOCK_REALTIME
+            "$PHC_CTL" "$dev" set 2>/dev/null
+            PHC_CTL_EXIT_CODE=$?
+            if [[ $PHC_CTL_EXIT_CODE -ne 0 ]]; then
+                echo "Error: Failed to sync clock for $dev (phc_ctl exit code: $PHC_CTL_EXIT_CODE)" >&2
+            fi
+        fi
+    done
+    sleep $SLEEP_INTERVAL
+done

platform/mellanox/docker-syncd-mlnx/supervisord.conf.j2

@@ -45,3 +45,13 @@ dependent_startup_wait_for=rsyslogd:running
 {% if ENABLE_ASAN == "y" %}
 environment=ASAN_OPTIONS="log_path=/var/log/asan/syncd-asan.log{{ asan_extra_options }}"
 {% endif %}
+
+[program:phcsync]
+command=/usr/bin/phcsync.sh
+priority=3
+autostart=false
+autorestart=false
+stdout_logfile=syslog
+stderr_logfile=syslog
+dependent_startup=true
+dependent_startup_wait_for=rsyslogd:running