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authorFurquan Shaikh <furquan@google.com>2020-05-15 16:04:28 -0700
committerPatrick Georgi <pgeorgi@google.com>2020-05-26 15:17:29 +0000
commitf4bc9eb2e652ca72554a4a0a5a221ee924a56f69 (patch)
treee1efcbb44e72f60c84c6c1ff377df10cd5b6f677 /gnat.adc
parent468bc6cd8f765016aa4e01e20e8f020ac820cbb7 (diff)
downloadcoreboot-f4bc9eb2e652ca72554a4a0a5a221ee924a56f69.tar.xz
device: Add support for resource allocator v4
This change adds back support for the resource allocator using multiple ranges as originally landed in CB:39486(commit hash 3b02006) and reverted in CB:41413(commit hash 6186cbc). The new resource allocator can be selected by Kconfig option RESOURCE_ALLOCATOR_V4. It was identified that there are some AMD chipsets in the tree that do not really work well with the dynamic resource allocation. Until these chipsets are fixed, old (v3) and new (v4) of the resource allocator need to live side-by-side in the tree. There were some other chipsets in the tree which originally demonstrated problems with the new resource allocator, but have been since fixed in the tree. This change picks up the same additions as performed in CB:39486 along with the following changes: 1. Changes to avoid fixed resources in the entire tree. Use of search_bus_resources() is replaced with a walk of the entire tree in avoid_fixed_resources(). This is required to ensure that all fixed resources added to any device (including domain) are taken into consideration to avoid overlap during dynamic resource allocation. 2. Changes to set up alignment for memranges when initializing them. This is done to ensure that the right granularity is used for IORESOURCE_IO(no special alignment) and IORESOURCE_MEM(4KiB) resource requests. 3. mark_resource_invalid() is dropped as the resource no longer needs to be marked in any special way if allocation is not being done. Instead setting of IORESOURCE_ASSIGNED flag is skipped in this case. 4. initialize_memranges() is updated to check IORESOURCE_ASSIGNED instead of base == limit. Original commit message: 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. Change-Id: Ide4d98528197bb03850a8fb4d73c41cd2c0195aa Signed-off-by: Furquan Shaikh <furquan@google.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/41443 Reviewed-by: Nico Huber <nico.h@gmx.de> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
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