[sonic_xcvr] Fix firmware download TypeError

[pnakka28]

Description

The CDB firmware block size fields come back from the module as floats. That float made it all to file.read() during firmware download, which only accepts an integer, so the download crashed with a TypeError on any EPL-capable module that didn't advertise the maximum block size.

Motivation and Context

Motivation and Context

Firmware download fails on any module that doesn't advertise the maximum block size:

    CDB: Starting firmware download
    Downloading ...  [------------------------------------]    0%
    Traceback (most recent call last):
      File "/usr/local/bin/sfputil", line 8, in <module>
        sys.exit(cli())
      ...
      File "/usr/local/lib/python3.13/dist-packages/sfputil/main.py", line 1725, in download
        status = download_firmware(port_name, filepath)
      File "/usr/local/lib/python3.13/dist-packages/sfputil/main.py", line 1580, in download_firmware
        data = fd.read(count)
    TypeError: argument should be integer or None, not 'float'
    CDB: Starting firmware download
    CDB: Start firmware download failed - status 67
    CDB: Starting firmware download
    CDB: Start firmware download failed - status 67

How Has This Been Tested?

• Modified unit tests and made sure they are passing
• With the fix, verified firmware downloaded successfully

On version 202605:
Hardware: Reproduced the TypeError on the unpatched code, then confirmed firmware download proceeds past block-write with the fix applied.
Unit tests: pytest tests/sonic_xcvr/test_cdb_fw.py

Additional Information (Optional)

MSFT ADO - 39388348

[azure-pipelines]

Azure Pipelines:
There may be pipelines that require an authorized user to comment /azp run to run.

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines:
Successfully started running 1 pipeline(s).

[Copilot]

Pull request overview

Fixes CDB firmware downloads by normalizing module-reported block sizes to integers before file reads.

Changes:

• Converts firmware payload and block sizes to integers.
• Adds coverage for floating-point EPL block sizes.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
sonic_platform_base/sonic_xcvr/cdb/cdb_fw.py	Normalizes firmware block-size fields.
tests/sonic_xcvr/test_cdb_fw.py	Verifies EPL block-size conversion.

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[mssonicbld]

The change is not in 202605 yet. @pnakka28, please manually create the cherry pick PR for branch 202605.
You can ping the release branch owner(github account: vaibhavhd) to approve your cherry pick PR.
If this change is already in 202605, please comment "already in 202605". Thanks!

_{---Powered by SONiC BuildBot}