Re: [PATCH V3 1/2] dt-bindings: PCI: tegra234: Add ECAM support

Rob Herring
2022-11-15T18:01:27Z

On Tue, Nov 15, 2022 at 10:03 AM Jon Hunter <jonathanh@nvidia.com> wrote:
>
>
> On 15/11/2022 02:01, Rob Herring wrote:
> > On Mon, Nov 14, 2022 at 03:53:32PM +0000, Jon Hunter wrote:
> >> From: Vidya Sagar <vidyas@nvidia.com>
> >>
> >> Add support for ECAM aperture that is only supported for Tegra234
> >> devices.
> >>
> >> Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
> >> Co-developed-by: Jon Hunter <jonathanh@nvidia.com>
> >> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
> >> ---
> >> Changes since V2:
> >> - Avoid duplication of reg items and reg-names
> >> Changes since V1:
> >> - Restricted the ECAM aperture to only Tegra234 devices that support it.
> >>
> >> .../bindings/pci/nvidia,tegra194-pcie.yaml | 34 +++++++++++++++++--
> >> .../devicetree/bindings/pci/snps,dw-pcie.yaml | 2 +-
> >> 2 files changed, 33 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/Documentation/devicetree/bindings/pci/nvidia,tegra194-pcie.yaml b/Documentation/devicetree/bindings/pci/nvidia,tegra194-pcie.yaml
> >> index 75da3e8eecb9..fe81d52c7277 100644
> >> --- a/Documentation/devicetree/bindings/pci/nvidia,tegra194-pcie.yaml
> >> +++ b/Documentation/devicetree/bindings/pci/nvidia,tegra194-pcie.yaml
> >> @@ -27,6 +27,7 @@ properties:
> >> - nvidia,tegra234-pcie
> >>
> >> reg:
> >> + minItems: 4
> >> items:
> >> - description: controller's application logic registers
> >> - description: configuration registers
> >> @@ -35,13 +36,16 @@ properties:
> >> available for software access.
> >> - description: aperture where the Root Port's own configuration
> >> registers are available.
> >> + - description: aperture to access the configuration space through ECAM.
> >>
> >> reg-names:
> >> + minItems: 4
> >> items:
> >> - const: appl
> >> - const: config
> >> - const: atu_dma
> >> - const: dbi
> >> + - const: ecam
> >
> > Wouldn't this be mutually exclusive with 'config'? 'config' is not
> > really h/w, but an just an iATU window typically.
>
> Yes that is true, however, I was chatting with Sagar and we really need
> both ranges to be defined.
>
> > Where's the driver change to use this?
>
> For Linux there is not one. However, we need this for our port of the
> EDK2 bootloader [0] that parses device-tree and can support booting
> Linux with either device-tree or ACPI. We wanted to have a common
> device-tree we can use for EDK2 and Linux.

Ok, makes sense.

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