2020-02-26 16:49:11

by Nicolas Saenz Julienne

Subject: [PATCH] ARM: dts: bcm2711: Add pcie0 alias

Some bcm2711 revisions have different DMA constraints on the their PCIE
bus. The lower common denominator, being able to access the lower 3GB of
memory, is the default setting for now. Newer SoC revisions are able to
access the whole memory space.

Raspberry Pi 4's firmware is aware of this limitation and will correct
the PCIE's dma-ranges property if a pcie0 alias is available. So add
it.

Fixes: d5c8dc0d4c88 ("ARM: dts: bcm2711: Enable PCIe controller")
Signed-off-by: Nicolas Saenz Julienne <[email protected]>
---
arch/arm/boot/dts/bcm2711-rpi-4-b.dts | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
index cb3385262705..479f6828d73f 100644
--- a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
+++ b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
@@ -21,6 +21,7 @@ memory@0 {

aliases {
ethernet0 = &genet;
+ pcie0 = &pcie0;
};

leds {
--
2.25.1

2020-02-26 17:18:19

by Phil Elwell

Subject: Re: [PATCH] ARM: dts: bcm2711: Add pcie0 alias

Hi Nicolas,

On 26/02/2020 16:46, Nicolas Saenz Julienne wrote:
> Some bcm2711 revisions have different DMA constraints on the their PCIE
> bus. The lower common denominator, being able to access the lower 3GB of
> memory, is the default setting for now. Newer SoC revisions are able to
> access the whole memory space.
>
> Raspberry Pi 4's firmware is aware of this limitation and will correct
> the PCIE's dma-ranges property if a pcie0 alias is available. So add
> it.

I can confirm that this is exactly what the firmware is looking for, so

Reviewed-by: Phil Elwell <[email protected]>

Phil

2020-02-27 19:30:15

by Florian Fainelli

Subject: Re: [PATCH] ARM: dts: bcm2711: Add pcie0 alias

On Wed, 26 Feb 2020 17:46:00 +0100, Nicolas Saenz Julienne <[email protected]> wrote:
> Some bcm2711 revisions have different DMA constraints on the their PCIE
> bus. The lower common denominator, being able to access the lower 3GB of
> memory, is the default setting for now. Newer SoC revisions are able to
> access the whole memory space.
>
> Raspberry Pi 4's firmware is aware of this limitation and will correct
> the PCIE's dma-ranges property if a pcie0 alias is available. So add
> it.
>
> Fixes: d5c8dc0d4c88 ("ARM: dts: bcm2711: Enable PCIe controller")
> Signed-off-by: Nicolas Saenz Julienne <[email protected]>
> ---

Applied to devicetree/fixes, thanks!
--
Florian