[coreboot-gerrit] Change in coreboot[master]: drivers/ocp/ipmi: Add ipmi POST start/end command

[Tim Chu (Code Review)]

Tim Chu has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/41605 )

Change subject: drivers/ocp/ipmi: Add ipmi POST start/end command
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Patch Set 4:
> Patch Set 4: -Code-Review
>
> With this design, POST start/end IPMI commands are sent during ramstage, when the IPMI_OCP device is initialized and finalized.
>
> Ideally the behavior should be similar to traditional firmware,I think:
> POST start IPMI command should be sent as early as possible, in romstage when IPMI communication is established.
> POST end IPMI command should be sent as late as possible, either in ramstage just before control is given to payload, or in Linuxboot uinit just before control is given to target OS.

For the POST end, function can work in u-root now.
For the POST start, since it is ocp specific, I'll add it in drivers/ocp/ipmi and call this function in mainboard_memory_init_params, which may execute in romstage and use ipmi_kcs_premem_init in CB:40234 to check BMC status. However it is a little complicated to use ocp specific command with normal command, I'll try to do it much more clearly.