Read SFP temperature from TRANSCEIVER_DOM_TEMPERATURE table

[vvolam]

Cherry-pick: sonic-net/sonic-platform-daemons#747

Description

This change modifies thermalctld to read SFP temperature and threshold data from Redis tables instead of making direct platform API calls to the hardware.

Changes:

• Read SFP temperature from TRANSCEIVER_DOM_TEMPERATURE table first, falling back to TRANSCEIVER_DOM_SENSOR table if not present
• Read SFP thresholds from TRANSCEIVER_DOM_THRESHOLD table first, falling back to TRANSCEIVER_DOM_SENSOR table if not present
• Use SfpUtilHelper.get_physical_to_logical() API to map SFP physical index to logical port name for Redis table lookup
• Add new _init_sfp_util_helper() method to initialize port mappings
• Add new _get_sfp_temperature_from_db() method to read temperature from Redis
• Add new _refresh_sfp_temperature_status() method to update SFP thermal status from Redis data

Motivation and Context

The xcvrd daemon already reads SFP DOM sensor data from hardware and populates Redis tables in STATE_DB. Having thermalctld also read directly from hardware causes:

1. Duplicate hardware access - Both xcvrd and thermalctld poll the same I2C devices
2. I2C bus contention - Multiple processes accessing the same bus can cause delays and errors
3. Inconsistent data - Different polling intervals can result in different temperature readings

This change makes thermalctld consume the cached data from xcvrd instead of polling hardware directly, reducing I2C traffic and ensuring consistent temperature data across SONiC components.

Related HLD: https://github.com/sonic-net/SONiC/blob/master/doc/nvidia-thermal-algorithm/improve-sonic-thermal-algo.md

How Has This Been Tested?

Tested on Nvidia SN5640 platform with 66 SFP modules:

1. Verified temperature values match Redis source:

   redis-cli -n 6 hgetall "TRANSCEIVER_DOM_SENSOR|Ethernet0" | grep -A1 temperature
   # Returns: 53.809
   
   show platform temperature | grep "xSFP module 1"
   # Shows: 53.809

2. Verified thresholds are read from TRANSCEIVER_DOM_THRESHOLD table:

 redis-cli -n 6 hgetall "TRANSCEIVER_DOM_THRESHOLD|Ethernet0"
 # Contains: temphighalarm, templowalarm, temphighwarning, templowwarning

 show platform temperature
 # Shows correct thresholds: High TH=75.0, Low TH=-5.0, Crit High=80.0, Crit Low=-10.0

3. Verified all 66 SFP modules show temperature data in show platform temperature
4. Verified TEMPERATURE_INFO table is correctly populated:

   redis-cli -n 6 hgetall "TEMPERATURE_INFO|xSFP module 1 Temp"
   # Contains: temperature, high_threshold, low_threshold, critical_high_threshold, etc.

Additional Information (Optional)
The implementation follows the HLD design which specifies:

Temperature: Read from STATE_DB::TRANSCEIVER_DOM_TEMPERATURE|Ethernet*.temperature
Thresholds: Read from STATE_DB::TRANSCEIVER_DOM_THRESHOLD|Ethernet*.temphighwarning/temphighalarm
Fallback to TRANSCEIVER_DOM_SENSOR table is provided for backward compatibility with platforms that don't have the new tables populated yet.

Command output after the changes:

$ show plat temp
                Sensor    Temperature    High TH    Low TH    Crit High TH    Crit Low TH    Warning          Timestamp
----------------------  -------------  ---------  --------  --------------  -------------  ---------  -----------------
                  ASIC           80.0        105       N/A             120            N/A      False  20260211 19:13:38
 Ambient Fan Side Temp         41.937        N/A       N/A             N/A            N/A      False  20260211 19:13:38
Ambient Port Side Temp         42.187        N/A       N/A             N/A            N/A      False  20260211 19:13:38
         CPU Pack Temp          43.25       95.0       N/A           100.0            N/A      False  20260211 19:13:38
            PSU-1 Temp            N/A        N/A       N/A             N/A            N/A      False  20260211 19:13:38
            PSU-2 Temp           42.5       63.0       N/A             N/A            N/A      False  20260211 19:13:38
            PSU-3 Temp            N/A        N/A       N/A             N/A            N/A      False  20260211 19:13:38
            PSU-4 Temp           41.0       63.0       N/A             N/A            N/A      False  20260211 19:13:38
         SODIMM 2 Temp          43.25       85.0       N/A            95.0            N/A      False  20260211 19:13:38
    xSFP module 1 Temp         53.809       75.0      -5.0            80.0          -10.0      False  20260211 19:13:38
    xSFP module 2 Temp         59.086       75.0      -5.0            80.0          -10.0      False  20260211 19:13:38
    xSFP module 3 Temp         56.512       75.0      -5.0            80.0          -10.0      False  20260211 19:13:38
    xSFP module 4 Temp         53.934       75.0      -5.0            80.0          -10.0      False  20260211 19:13:38
    xSFP module 5 Temp          54.75       75.0      -5.0            80.0          -10.0      False  20260211 19:13:38
    xSFP module 6 Temp         64.375       75.0      -5.0            80.0          -10.0      False  20260211 19:13:38
    xSFP module 7 Temp         63.812       75.0      -5.0            80.0          -10.0      False  20260211 19:13:38
    xSFP module 8 Temp         55.645       75.0      -5.0            80.0          -10.0      False  20260211 19:13:38
    xSFP module 9 Temp         56.277       75.0      -5.0            80.0          -10.0      False  20260211 19:13:38
   xSFP module 10 Temp         64.066       75.0      -5.0            80.0          -10.0      False  20260211 19:13:38

[judyjoseph]

LGTM