[Mellanox] Use sdk sysfs instead of ethtool

[Junchao-Mellanox]

Why I did it

Currently, implementation:

• Reading EEPROM: via ethtool
• Writing EEPROM: via mlxreg tool.

The problem is that spawning new process of ethtool/mlxreg is very slow. To optimize the performance, this PR will use SDK provided sys fs for EEPROM reading/writing.

How I did it

Replace the logic of sfp.read_eeprom and sfp.write_eeprom by SDK sys fs.

How to verify it

Manual test
Unit test cases (new test case added)
sonic-mgmt regression

Which release branch to backport (provide reason below if selected)

• 201811
• 201911
• 202006
• 202012
• 202106
• 202111
• 202205

Description for the changelog

Ensure to add label/tag for the feature raised. example - PR#2174 where, Generic Config and Update feature has been labelled as GCU.

Link to config_db schema for YANG module changes

A picture of a cute animal (not mandatory but encouraged)

[liat-grozovik]

@Junchao-Mellanox now that PR #12542 is merged, should this PR be ready for review?

[prgeor]

@Junchao-Mellanox do you mind testing your changes with sonic-net/sonic-utilities#2379 ?

[Junchao-Mellanox]

@Junchao-Mellanox do you mind testing your changes with sonic-net/sonic-utilities#2379 ?

Sure

[Junchao-Mellanox]

Hi @prgeor , I ran some tests based on sonic-net/sonic-utilities#2379. I did not find issue on the current bug, but I found sonic-net/sonic-utilities#2379 itself contains some issues:

1. This line is a confusing, https://github.com/sonic-net/sonic-utilities/blob/569edf3b75840b1db844c5a4797679babc412c4e/sfputil/main.py#L738. Better change name eeprom_hexdump_sff8636 to something else because it is not only for sff8636.

        if id[0] == 0x3:
            output = eeprom_hexdump_sff8472(port, physical_port, page)
        else:
            output = eeprom_hexdump_sff8636(port, physical_port, page)

2. A2H is not a mandatory for sff8472, but the command line output nothing if A2H is not available:

        page_dump = platform_chassis.get_sfp(physical_port).read_eeprom(SFF8472_A0_SIZE, PAGE_SIZE)
        if page_dump is None:
            click.echo("Error: Failed to read EEPROM for A2h!")
            sys.exit(ERROR_NOT_IMPLEMENTED)

[Junchao-Mellanox]

No clean cherry-pick, will create PR to 202205