On Mon, Mar 10, 2025 at 10:01:32AM +0100, Patrick Rudolph wrote: > Legacy PCI devices, like qemu's Bochs VGA device, are allowed to have > prefetchable 32-bit BARs, while PCIe devices are not allowed to have > 32-bit prefetchable BARs. Typically prefetchable BARs are 64-bit and > typically the prefetch MMIO window is also 64-bit and placed above > 4GiB, as it's the case on qemu sbsa-ref. > > Currently the U-Boot code assumes that prefetchable BARs are > 64-bit BARs and always tries to assign them into the prefetch > MMIO window. > > When a 32-bit BAR is marked as prefetch, but the prefetch area is > not within the first 4GiB of the address space, then downgrade the > BAR and place it in the non-prefetch MMIO window. > > For prefetch BARs there's no downside on being placed in non prefetch > MMIO areas, besides the possible slower performance when a driver tries > to map it Write-Combine. > > TEST: Fixes pci_auto on QEMU sbsa-ref fails to autoconfigure BAR0. > > Signed-off-by: Patrick Rudolph <patrick.rudo...@9elements.com>
Do we need this series for v2025.04 or v2025.07? Thanks! -- Tom
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