Re: [PATCH] arm64: dts: marvell: armada-37xx: Remap IO space to bus address 0x0

Marek Behún
2022-02-19T11:36:34Z

On Fri, 18 Feb 2022 22:25:26 +0100
Pali Rohár <pali@kernel.org> wrote:

> Remap PCI I/O space to the bus address 0x0 in the Armada 37xx
> device-tree in order to support legacy I/O port based cards which have
> hardcoded I/O ports in low address space.
>
> Some legacy PCI I/O based cards do not support 32-bit I/O addressing.
>
> Since commit 64f160e19e92 ("PCI: aardvark: Configure PCIe resources from
> 'ranges' DT property") this driver can work with I/O windows which have
> a different address for CPU than for PCI bus (unless there is some
> conflict with other A37xx mapping), without needing additional support
> for this in the firmware.
>
> Note that DDR on A37xx is mapped to bus address 0x0 and that mapping of
> I/O space can be set to address 0x0 too because MEM space and I/O space
> are separate and so they do not conflict.
>
> Signed-off-by: Pali Rohár <pali@kernel.org>
> Reported-by: Arnd Bergmann <arnd@arndb.de>

Reviewed-by: Marek Behún <kabel@kernel.org>