hwp-pmx: reset protection code in clear_alarm

[ykyohei]

Description

Minor debug of hwp-pmx.
We need to reset the protection code (self.prot) in clear_alarm task.
This was implemented in the previous version of agent (following link), but I forgot to include this self.prot reset when we refactored the hwp-pmx agent to be TimoutLock less.

socs/socs/agents/hwp_pmx/agent.py

Line 129 in 288fb5c

self.prot = 0

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[d1ssk]

Looks good.

[jlashner]

Seems like this could also be done by allowing prot to be set back to 0 in the acq function:

socs/socs/agents/hwp_pmx/agent.py

Lines 297 to 298 in 288fb5c

	if prot_code != 0:
	self.prot = prot_code

Is there a reason we don't do that? It's generally preferable to read from hardware when possible instead of setting value directly in the agent.

[ykyohei]

Agree that it's generally preferable to read from hardware. But this is intentional.

When the pmx protection is triggered, pmx outputs protection code only once, you will get 0 from the second queries. However, pmx remains in protected state. If you run clear_alarm, pmx will go back to the normal state. If there is still problem, pmx will output protection code again, but only once.

For this reason, we made the agent to have self.prot for monitoring purposes.

[jlashner]

Makes sense, thanks!