On Tue, Mar 11, 2025 at 08:54:55AM +0100, Krzysztof Kozlowski wrote: > On 11/03/2025 06:01, Varadarajan Narayanan wrote: > > On Mon, Mar 10, 2025 at 12:37:28PM +0100, Krzysztof Kozlowski wrote: > >> On 10/03/2025 08:44, Varadarajan Narayanan wrote: > >>> On Thu, Mar 06, 2025 at 01:06:13PM +0100, Krzysztof Kozlowski wrote: > >>>> On 06/03/2025 12:52, Krzysztof Kozlowski wrote: > >>>>> On 20/02/2025 10:42, Varadarajan Narayanan wrote: > >>>>>> All DT entries except "reg" is similar between ipq5332 and ipq9574. ipq9574 > >>>>>> has 5 registers while ipq5332 has 6. MHI is the additional (i.e. sixth > >>>>>> entry). Since this matches with the sdx55's "reg" definition which allows > >>>>>> for 5 or 6 registers, combine ipq9574 with sdx55. > >>>>>> > >>>>>> This change is to prepare ipq9574 to be used as ipq5332's fallback > >>>>>> compatible. > >>>>>> > >>>>>> Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > >>>>>> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx> > >>>>> > >>>>> Unreviewed. > >>>>> > >>>>>> Signed-off-by: Varadarajan Narayanan <quic_varada@xxxxxxxxxxx> > >>>>>> --- > >>>>>> v8: Add 'Reviewed-by: Krzysztof Kozlowski' > >>>>>> --- > >>>>>> Documentation/devicetree/bindings/pci/qcom,pcie.yaml | 2 +- > >>>>>> 1 file changed, 1 insertion(+), 1 deletion(-) > >>>>>> > >>>>>> diff --git a/Documentation/devicetree/bindings/pci/qcom,pcie.yaml b/Documentation/devicetree/bindings/pci/qcom,pcie.yaml > >>>>>> index 7235d6554cfb..4b4927178abc 100644 > >>>>>> --- a/Documentation/devicetree/bindings/pci/qcom,pcie.yaml > >>>>>> +++ b/Documentation/devicetree/bindings/pci/qcom,pcie.yaml > >>>>>> @@ -169,7 +169,6 @@ allOf: > >>>>>> enum: > >>>>>> - qcom,pcie-ipq6018 > >>>>>> - qcom,pcie-ipq8074-gen3 > >>>>>> - - qcom,pcie-ipq9574 > >>>>> > >>>>> Why you did not explain that you are going to affect users of DTS? > >>>>> > >>>>> NAK > >>> > >>> Sorry for not explicitly calling this out. I thought that would be seen from the > >>> following DTS related patches. > >>> > >>>> I did not connect the dots, but I pointed out that you break users and > >>>> your DTS is wrong: > >>>> https://lore.kernel.org/all/f7551daa-cce5-47b3-873f-21b9c5026ed2@xxxxxxxxxx/ > >>>> > >>>> so you should come back with questions to clarify what to do, not keep > >>>> pushing this incorrect patchset. > >>>> > >>>> My bad, I should really have zero trust. > >>> > >>> It looks like it is not possible to have ipq9574 as fallback (for ipq5332) > >>> without making changes to ipq9574 since the "reg" constraint is different > >>> between the two. And this in turn would break the ABI w.r.t. ipq9574. > >> > >> I don't get why this is not possible. You have one list for ipq9574 and > >> existing compatible devices, and you add second list for new device. > >> > >> ... or you just keep existing order. Why you need to keep changing order > >> every time you add new device? > > > > Presently, sdx55 and ipq9574 have the following reg/reg-names constraints. > > > > compatible | qcom,pcie-sdx55 | qcom,pcie-ipq9574 > > ----------------+-----------------------+------------------ > > reg minItems| 5 | 5 > > maxItems| 6 | 5 > > ----------------+-----------------------+------------------ > > reg-names | | > > minItems| 5 | 5 > > ----------------+-----------------------+------------------ > > maxItems| | 5 (6 for ipq5332) > > ----------------+-----------------------+------------------ > > items | | > > | parf | dbi > > | dbi | elbi > > | elbi | atu > > | atu | parf > > | config | config > > | mhi | (add mhi for ipq5332) > > ----------------+-----------------------+------------------ > > > > To make ipq9574 as fallback for ipq5332, have to add "mhi" to reg-names of > > ipq9574. > > only ipq5332 gets additional item, not ipq9574. Your sentence is not > correct. You do not have to add mhi to ipq9574. Neither we, nor schema > asked you to do this. > > > > Once I add that, the sdx55 and ipq9574 is the same list but in > > different order. > > > > You cannot change the order in existing devices. Ok. > > If this would not be considered as duplication of the same constraint, then I > > can club ipq5332 with ipq9574. > > > > If this would be considered as duplication, then sdx55 and ipq9574 would have to > > use the same reg-names list and sdx55 or ipq9574 reg-names order would change. > > > >>> To overcome this, two approaches seem to be availabe > >>> > >>> 1. Document that ipq9574 is impacted and rework these patches to > >>> minimize the impact as much as possible > >> > >> What impact? What is the reason to impact ipq9574? What is the actual issue? > > > > By impact, I meant the change in the reg-names order as mentioned above (for > > considered as duplication). > > Then you must eliminate the impact, not minimize it. Ok. > >>> (or) > >>> > >>> 2. Handle ipq5332 as a separate compatible (without fallback) and reuse > >>> the constraints of sdx55 for "reg" and ipq9574 for the others (like > >>> clock etc.). This approach will also have to revert [1], as it > >>> assumes ipq9574 as fallback. > >>> > >>> Please advice which of the above would be appropriate. If there is a better 3rd > >>> alternative please let me know, will align with that approach. > >> > >> Keep existing order. Why every time we see new device, it comes up with > >> a different order? > > > > Will be able to do that based on the answer to 'duplication' question and how to > > handle that. > > I don't understand what is duplication of something here. By duplication, I meant the same set of reg-names (in different order). > > if (adding mhi to ipq9574 reg-names != duplication) > > > > /* Keep existing order */ > > > > * Append "mhi" to ipq9574 > > ipq9574 does not have mhi, does it? ipq9574 also has it. > If it has, it should be separate patch with its own explanation of the > hardware. Will discard these patches from the patchset - dt-bindings: PCI: qcom: Use sdx55 reg description for ipq9574 Varadarajan Narayanan arm64: dts: qcom: ipq9574: Reorder reg and reg-names Varadarajan Narayanan Will add mhi for ipq9574 and post the next version. Is that ok? Thanks Varada
