Change in coreboot[master]: [RFC] treewide: move config MAX_CPUS to chipset scope

[Angel Pons (Code Review)]

Angel Pons has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/37728 )

Change subject: [RFC] treewide: move config MAX_CPUS to chipset scope
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Patch Set 1:
> Patch Set 1:
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> are you sure? If we ever get back to supporting servers, then max_cpus is number sockets * cpus per socket, I figure. Or am I missing something
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> Historical note: back in the earliest days, before more than one core per socket, MAX_CPUS was indeed just the number of sockets, and hence purely a mainboard thing. How times change :-)

Then I would just add another Kconfig option, e.g. NUM_SOCKETS or something like that. Then, platforms which can support more than one CPU would just need to override NUM_SOCKETS.

In any case, even the current approach can account for exceptions. The platform default is meant to be the max number of CPU cores that can possibly exist as per chipset limitations, but of course some boards might have additional limitations. For example, consider a LGA1155 AIO mainboard: suppose that it has a VRM and thermal solution that can only handle CPUs with a TDP of up to 35W. This means no quad-core CPUs can run on it, so MAX_CPUS could be 4.