Doc/relnotes/4.13: Add details about resource allocator v4

This change adds details about the new resource allocator v4 in
coreboot to the release notes for 4.13.

Change-Id: I7071bdf0faffda61fc5941886c963181939c07e3
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47660
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
This commit is contained in:
Furquan Shaikh 2020-11-16 23:05:35 -08:00 committed by Angel Pons
parent 900c3a32a3
commit a8e7b45816
1 changed files with 29 additions and 0 deletions

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@ -122,6 +122,16 @@ can be changed via `get_option()`. Keeping the log level of the first
console static ensures that we can see console output even if there's
a bug in the more involved code to query options.
### Resource allocator v4
A new revision of resource allocator v4 is now added to coreboot that supports
mutiple ranges for allocating resources. Unlike the previous allocator (v3), it does
not use the topmost available window for allocation. Instead, it uses the first
window within the address space that is available and satisfies the resource request.
This allows utilization of the entire available address space and also allows
allocation above the 4G boundary. The old resource allocator v3 is still retained for
some AMD platforms that do not conform to the requirements of the allocator.
### Add significant changes here
Deprecations
@ -132,3 +142,22 @@ Deprecations
In order to minimize the usage of PCI bus mastering, the options we introduced in
this release will be dropped in a future release again. For more details, please
see [Preparations to minimize enabling PCI bus mastering](#preparations-to-minimize-enabling-pci-bus-mastering-in-coreboot).
### Resource allocator v3
Resource allocator v3 is retained in coreboot tree because the following platforms
do not conform to the requirements of the resource allocation i.e. not all the fixed
resources of the platform are provided during the `read_resources()` operation:
* northbridge/amd/pi/00630F01
* northbridge/amd/pi/00730F01
* northbridge/amd/pi/00660F01
* northbridge/amd/agesa/family14
* northbridge/amd/agesa/family15tn
* northbridge/amd/agesa/family16kb
In order to have a single unified allocator in coreboot, this notice is being added
to ensure that the platforms listed above are fixed before the next release. If there
is interest in maintaining support for these platforms beyond the next release,
please ensure that the platforms are fixed to conform to the expectations of resource
allocation.