Re: [PATCH v3 4/4] arm64: dts: rockchip: Update PCI host bridge window to 32-bit address memory

On Thu, Jun 10, 2021 at 3:50 PM Heiko Stübner [off-list ref] wrote:

Hi,

Am Montag, 7. Juni 2021, 13:28:56 CEST schrieb Punit Agrawal:

quoted

The PCIe host bridge on RK3399 advertises a single 64-bit memory
address range even though it lies entirely below 4GB.

Previously the OF PCI range parser treated 64-bit ranges more
leniently (i.e., as 32-bit), but since commit 9d57e61bf723 ("of/pci:
Add IORESOURCE_MEM_64 to resource flags for 64-bit memory addresses")
the code takes a stricter view and treats the ranges as advertised in
the device tree (i.e, as 64-bit).

The change in behaviour causes failure when allocating bus addresses
to devices connected behind a PCI-to-PCI bridge that require
non-prefetchable memory ranges. The allocation failure was observed
for certain Samsung NVMe drives connected to RockPro64 boards.

Update the host bridge window attributes to treat it as 32-bit address
memory. This fixes the allocation failure observed since commit
9d57e61bf723.

Reported-by: Alexandru Elisei <redacted>
Link: https://lore.kernel.org/r/7a1e2ebc-f7d8-8431-d844-41a9c36a8911@arm.com (local)
Suggested-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Punit Agrawal <redacted>
Tested-by: Alexandru Elisei <redacted>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Rob Herring <robh+dt@kernel.org>

just for clarity, should I just pick this patch separately for 5.13-rc to
make it easy for people using current kernel devicetrees, or should
this wait for the update mentioned in the cover-letter response
and should go all together through the PCI tree?

This was dropped from v4, but should still be applied IMO.

Acked-by: Rob Herring <robh@kernel.org>

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