On Tue, Mar 28, 2023 at 01:22:26PM +0200, Krzysztof Kozlowski wrote: > 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. Okay, great. Sumit, you can resolve this by adding a "deprecated: true" to the EMC's nvidia,bpmp property schema. In the driver we can then try to look at the MC's ->bpmp and if it exists reuse that. If it doesn't exist, we can keep the existing lookup as a fallback for device trees that haven't been updated yet.
Attachment:
signature.asc
Description: PGP signature
