device: Enable resource allocator to use multiple ranges
This change updates the resource allocator in coreboot to allow using multiple ranges for resource allocation rather than restricting available window to a single base/limit pair. This is done in preparation to allow 64-bit resource allocation. Following changes are made as part of this: a) Resource allocator still makes 2 passes at the entire tree. The first pass is to gather the resource requirements of each device under each domain. It walks recursively in DFS fashion to gather the requirements of the leaf devices and propagates this back up to the downstream bridges of the domain. Domain is special in the sense that it has fixed resource ranges. Hence, the resource requirements from the downstream devices have no effect on the domain resource windows. This results in domain resource limits being unmodified after the first pass. b) Once the requirements for all the devices under the domain are gathered, resource allocator walks a second time to allocate resources to downstream devices as per the requirements. Here, instead of maintaining a single window for allocating resources, it creates a list of memranges starting with the resource window at domain and then applying constraints to create holes for any fixed resources. This ensures that there is no overlap with fixed resources under the domain. c) Domain does not differentiate between mem and prefmem. Since they are allocated space from the same resource window at the domain level, it considers all resource requests from downstream devices of the domain independent of the prefetch type. d) Once resource allocation is done at the domain level, resource allocator walks down the downstream bridges and continues the same process until it reaches the leaves. Bridges have separate windows for mem and prefmem. Hence, unlike domain, the resource allocator at bridge level ensures that downstream requirements are satisfied by taking prefetch type into consideration. e) This whole 2-pass process is performed for every domain in the system under the assumption that domains do not have overlapping address spaces. Noticeable differences from previous resource allocator: a) Changes in print logs observed due to flows being slightly different. b) Base, limit and size of domain resources are no longer updated based on downstream requirements. c) Memranges are used instead of a single base/limit pair for determining resource allocation. d) Previously, if a resource request did not fit in the available base/limit window, then the resource would be allocated over DRAM or any other address space defeating the principle of "no overlap". With this change, any time a resource cannot fit in the available ranges, it complains and ensures that the resource is effectively disabled by setting base same as the limit. e) Resource allocator no longer looks at multiple links to determine the right bus for a resource. None of the current boards have multiple buses under any downstream device of the domain. The only device with multiple links seems to be the cpu cluster device for some AMD platforms. BUG=b:149186922 TEST=Verified that resource allocation looks correct based on addresses assigned on Volteer. Signed-off-by: Furquan Shaikh <furquan@google.com> Change-Id: Ia1f089877c62e119c6a994a10809c9cc0050ec9a Reviewed-on: https://review.coreboot.org/c/coreboot/+/39486 Reviewed-by: Aaron Durbin <adurbin@chromium.org> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
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