Add domain-aware PCIe handling and improve pcie_common robustness

[t2sharma]

Description:
This PR enhances pcie_common.py to support domain-aware PCIe enumeration and improves overall robustness and safety of the utility.

Problem:
The current upstream implementation:

Assumes PCI domain is implicitly 0000
Uses non-domain-aware lspci output
Uses unsafe YAML parsing (yaml.load)
Does not handle duplicate PCIe entries
Lacks visibility into PCIe AER error statistics

This leads to incorrect PCIe detection on platforms where:

PCI domains are non-zero
Multiple devices share similar BDF across domains

Changes:

1. Domain-aware PCIe enumeration
   Switched to:
   lspci -D
   lspci -D -n
   Parses full BDF: domain:bus:device.function

2. Added domain support in validation
   get_pcie_check() now validates using:
   domain + bus + device + function
   Backward compatible (defaults to "0000")

3. Safer YAML parsing:
   yaml.safe_load()

4. Duplicate PCIe filtering:
   Avoids duplicate entries using (domain, bus, dev, fn) key

5. Vendor ID capture:
   Adds vendor field for better device identification

6. Improved subprocess handling
   Checks return codes
   Captures stderr

7. AER stats support (new feature)
   Added:
   get_pcie_aer_stats()
   Reads from:
   /sys/bus/pci/devices/.../aer_dev_*

8. Config file improvements
   Supports revision-based configs:
   pcie_.yaml
   Preserves YAML key order (sort_keys=False)
   Backward Compatibility
   Existing configs without domain continue to work (default = 0000)
   No breaking change to existing workflows
   Existing CLI behavior unchanged
   Validation
   Verified PCIe detection on Arctos platform
   Compared output with:
   lspci -D

Confirmed:
Correct domain parsing
No duplicate entries
Accurate sysfs validation

Impact:
Enables correct PCIe validation on multi-domain platforms
Improves debugging visibility (AER stats)
Makes code safer and more maintainable

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: bgallagher-nexthop / name: Brian Gallagher (d1ac271)
• ✅ login: t2sharma / name: t2sharma (1ebc138, d1ac271, ba6575d)

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[bmridul]

Pls add a sample UT log.

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[t2sharma]

@bgallagher-nexthop I checked the CI log (Azure Pipelines / Azure.sonic-platform-common) in detail. The failure is in tests/pcie_common_test.py, where the mock still expects ['sudo', 'lspci'] and ['sudo', 'lspci', '-n']. The updated implementation now correctly uses domain-aware commands ['sudo', 'lspci', '-D'] and ['sudo', 'lspci', '-D', '-n'], so the mock falls through and output never gets assigned, causing the UnboundLocalError. We need to update the unit test mock to match the new commands, and also update the expected PCIe entries to include the new domain field returned by the implementation. Please help with updating of the script for Pipeline to Pass.

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[t2sharma]

manual ut -f
pcie_module_UT.txt