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SubjectRe: [RFC/RFT v2 09/11] dt-bindings: pci: add lane-map to rockchip PCIe binding
On Tue, Apr 26, 2022 at 03:21:37PM +0200, Frank Wunderlich wrote:
> From: Frank Wunderlich <frank-w@public-files.de>
>
> Create new property for (rockchip) PCIe controller binding to
> define lane mapping.
>
> Rockchip driver uses this for bifurcation (true/false) based
> on lanes should be splitted across controllers or not.
>
> On rk3568 there are 2 PCIe Controllers which share 2 PCIe lanes.
>
> pcie3x1: pcie@fe270000 //lane1 when using 1+1
> pcie3x2: pcie@fe280000 //lane0 when using 1+1
>
> This ends up in one Controller (pcie3x1) uses lane-map = <0 1>; and
> the other lane-map = <1 0>; (pcie3x2)
>
> This means there are 2 lanes (count of numbers), one (by position)
> is mapped to the first controller, the other one is used on the other
> controller.
>
> In rockchip PCIe driver the lane-map is simply converted to the
> bifurcation bool instead of direct mapping a specific lane to a
> controller.
>
> There is not yet any slot mapping below one controller.
> But for binding this may be possible like:
>
> lane-map = <1 2 3 3 4 4 4 4>;
> | | | ...
> lane0 | |
> lane1 |
> lane2
>
> on a 8-lane phy.
>
> This can map lane0 to port1 (number used at this position),
> lane1 to port2, lanes 2+3 to port 3 and lanes 4,5,6,7 to port 4.
>
> Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
> ---
> v2:
> - new patch
> ---
> Documentation/devicetree/bindings/pci/rockchip-dw-pcie.yaml | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/pci/rockchip-dw-pcie.yaml b/Documentation/devicetree/bindings/pci/rockchip-dw-pcie.yaml
> index a992970e8b85..998b20b3a9dc 100644
> --- a/Documentation/devicetree/bindings/pci/rockchip-dw-pcie.yaml
> +++ b/Documentation/devicetree/bindings/pci/rockchip-dw-pcie.yaml
> @@ -52,6 +52,8 @@ properties:
> - const: pclk
> - const: aux
>
> + lane-map: true
> +
> msi-map: true
>
> num-lanes: true
> @@ -74,8 +76,6 @@ properties:
> reset-names:
> const: pipe
>
> - bifurcation: true
> -

Why are you adding "bifurcation" earlier in the series, then
immediately removing it? Why not just add "lane-map" directly and
never mention "bifurcation" in the DT at all?

> vpcie3v3-supply: true
>
> required:
> @@ -115,6 +115,7 @@ examples:
> "aclk_dbi", "pclk",
> "aux";
> device_type = "pci";
> + lane-map = <0 1>;
> linux,pci-domain = <2>;
> max-link-speed = <2>;
> msi-map = <0x2000 &its 0x2000 0x1000>;
> --
> 2.25.1
>
>
> --
> linux-phy mailing list
> linux-phy@lists.infradead.org
> https://lists.infradead.org/mailman/listinfo/linux-phy

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