On 28/03/2023 12:48, Thierry Reding wrote: > On Tue, Mar 28, 2023 at 09:23:04AM +0200, Krzysztof Kozlowski wrote: >> On 27/03/2023 18:14, Sumit Gupta wrote: >>> For Tegra234, add the "nvidia,bpmp" property within the Memory >>> Controller (MC) node to reference BPMP node. This is needed in >>> the MC driver to pass the client info to the BPMP-FW when memory >>> interconnect support is available. >>> >>> Signed-off-by: Sumit Gupta <sumitg@xxxxxxxxxx> >>> --- >>> .../bindings/memory-controllers/nvidia,tegra186-mc.yaml | 7 +++++++ >>> 1 file changed, 7 insertions(+) >>> >>> diff --git a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra186-mc.yaml b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra186-mc.yaml >>> index 935d63d181d9..398d27bb2373 100644 >>> --- a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra186-mc.yaml >>> +++ b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra186-mc.yaml >>> @@ -58,6 +58,10 @@ properties: >>> "#interconnect-cells": >>> const: 1 >>> >>> + nvidia,bpmp: >>> + $ref: /schemas/types.yaml#/definitions/phandle >>> + description: phandle of the node representing the BPMP >> >> Why do you need this multiple times? Both in parent and all external-mc >> children? > > We've had nvidia,bpmp in the external memory controller node since > basically the beginning because we've always needed it there. For newer > chips we now also need it for the memory controller. > > Ideally I think we would only have this in the MC and have the EMC > driver reference it via the EMC's parent (i.e. MC), but that would break > backwards-compatibility. Reaching into the EMC's DT node from the MC was > another option that we discussed internally, but it didn't look right > given how this is also needed by the MC. > > One thing we could potentially do is deprecate the nvidia,bpmp phandle > in the EMC and only keep it as a fallback in the drivers in case the > parent MC doesn't find it's own in the DT. Yes, deprecation would answer to my question. Best regards, Krzysztof
