[SRU][J:linux-bluefield][PATCH v2 0/1] UBUNTU: SAUCE: mlxbf-gige: Support workaround for MDIO GPIO degradation bug

[Asmaa Mnebhi]

From: asmaa <asmaa at nvidia.com>

BugLink: https://bugs.launchpad.net/bugs/2086791

SRU Justification:

[Impact]

Once the BF3 MDIO clock is enabled by software it is expected and intended
for it to keep toggling. BF3 has a hardware GPIO bug where constant
toggling at "high frequencies" will lead to GPIO degradation.

[Fix]

* A workaround is to lower down the clock frequency.
* That will increase the "life expectation" of the GPIO.
* The lowest possible frequency we can achieve is 1.09Mhz by setting mdio_period = 0xFF.

[Test Case]

* Check if the gige driver is loaded
* Check that the oob_net0 interface is up and operational
* Check that the OOB gets an ip
* Do SW reset and powercycle and check the oon_net0 interface again

[Regression Potential]

* Lowering the frequency shouldn't have any impact but it controls
* the access to the PHY registers.
* So do the usual OOB tests to verify that there is indeed no impact.