[Design] PSU firmware update

[Derek Howard]

On 6/9/2019 10:16 PM, Lei YU wrote:
>>> 3 more quick notes:
>>>
>>> 1) PSs can be hot pluggable, so when a new one is detected, the code
>>> update should run then too if the new PS needs one, assuming all other
>>> conditions are met.
>>>
>>> 2) A single system may support multiple models of PS (will definitely
>>> happen for us), so this design should be able to store multiple PS
>>> images and send the correct image to the correct model.
>>>
>>> 3) You mentioned the combined image stuff before.  We should just check
>>> the timeline for that support aligns with this one.
>>>
>>>
>> Good point Matt on the PS install.  It would probably be a good idea to
>> get the newly installed PS to the same image as the rest of the PS's in
>> the system.
> Yup, really good point.
> This implies that BMC shall keep a local copy of the PSU image for future
> updates.
>
>> We do support PS's that don't provide control supply (standby voltage)
>> when reset at the end of the update, while other PS's do.  Therefore for
>> the former case, if only 1 PS has AC attached, we cannot update/reset
>> that PS, so please let that be selectable by the user (eg vendor
>> specific tool).
> This is somehow complex, but if we could defer this to vendor specific tool,
> that's OK.
> However, if a system has multiple models of PS, I am not sure how the vendor
> specific tool will be.
> Should we defer that to vendor specfic tool, too?
Sounds fine to me, thanks.
>> Also, please provide a way to know that the updates have finished.  As
>> we don't want to update the PS's when the power is on (this is vendor
>> specific as well), we also do not want to power the system on in the
>> middle of an update.  For example, if after a BMC update the PS's are
>> being updated, we want to hold off the next system power on until the PS
>> updates have finished. Thanks.
> This is already supported by the existing interface.
Excellent!
>
>>>
>>>>> The reason I ask is because if we could get clear requirements, it
>>>>> is possible
>>>>> to simplify the design.
>> Would it be possible to support both methods?  The general use case
>> being done during/after BMC code update, but also support the more
>> manual method that could be used perhaps in the lab to test new psu
>> images or in the field if there are problems with an existing image? Thanks.
> This design doc will be updated to support both cases.
>