On Wed, Aug 29, 2018 at 6:23 AM Vivek Gautam <vivek.gautam@xxxxxxxxxxxxxx> wrote: > > On Wed, Aug 29, 2018 at 2:05 PM Vivek Gautam > <vivek.gautam@xxxxxxxxxxxxxx> wrote: > > > > Hi Rob, > > > > > > On 8/29/2018 2:04 AM, Rob Herring wrote: > > > On Mon, Aug 27, 2018 at 04:25:50PM +0530, Vivek Gautam wrote: > > >> Add bindings doc for Qcom's smmu-v2 implementation. > > >> > > >> Signed-off-by: Vivek Gautam <vivek.gautam@xxxxxxxxxxxxxx> > > >> Reviewed-by: Tomasz Figa <tfiga@xxxxxxxxxxxx> > > >> Tested-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx> > > >> --- > > >> > > >> Changes since v14: > > >> - This is a new patch added in v15 after noticing the new > > >> checkpatch warning for separate dt-bindings doc. > > >> - This patch also addresses comments given by Rob and Robin to add > > >> a list of valid values of '<soc>' in "qcom,<soc>-smmu-v2" > > >> compatible string. > > >> > > >> .../devicetree/bindings/iommu/arm,smmu.txt | 47 ++++++++++++++++++++++ > > >> 1 file changed, 47 insertions(+) > > >> > > >> diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.txt b/Documentation/devicetree/bindings/iommu/arm,smmu.txt > > >> index 8a6ffce12af5..52198a539606 100644 > > >> --- a/Documentation/devicetree/bindings/iommu/arm,smmu.txt > > >> +++ b/Documentation/devicetree/bindings/iommu/arm,smmu.txt > > >> @@ -17,10 +17,24 @@ conditions. > > >> "arm,mmu-401" > > >> "arm,mmu-500" > > >> "cavium,smmu-v2" > > >> + "qcom,<soc>-smmu-v2", "qcom,smmu-v2" > > > The v2 in the compatible string is kind of redundant unless the SoC has > > > other SMMU types. > > > > sdm845 has smmu-v2, and smmu-500 [1]. > > > > >> > > >> depending on the particular implementation and/or the > > >> version of the architecture implemented. > > >> > > >> + A number of Qcom SoCs use qcom,smmu-v2 version of the IP. > > >> + "qcom,<soc>-smmu-v2" represents a soc specific compatible > > >> + string that should be present along with the "qcom,smmu-v2" > > >> + to facilitate SoC specific clocks/power connections and to > > >> + address specific bug fixes. > > >> + '<soc>' string in "qcom,<soc>-smmu-v2" should be one of the > > >> + following: > > >> + msm8996 - for msm8996 Qcom SoC. > > >> + sdm845 - for sdm845 Qcom Soc. > > > Rather than all this prose, it would be simpler to just add 2 lines with > > > the full compatibles rather than <soc>. The <soc> thing is not going to > > > work when/if we move bindings to json-schema also. > > > > then we keep adding > > "qcom,msm8996-smmu-v2", "qcom,smmu-v2" > > "qcom,msm8998-smmu-v2", "qcom,smmu-v2" > > "qcom,sdm845-smmu-v2", "qcom,smmu-v2", > > and from [1] > > "qcom,sdm845-smmu-500", "arm,mmu-500", etc. > > for each SoCs? > > How about following diff on top of this patch? > > diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.txt > b/Documentation/devicetree/bindings/iommu/arm,smmu.txt > index 52198a539606..5e6c04876533 100644 > --- a/Documentation/devicetree/bindings/iommu/arm,smmu.txt > +++ b/Documentation/devicetree/bindings/iommu/arm,smmu.txt > @@ -17,23 +17,18 @@ conditions. > "arm,mmu-401" > "arm,mmu-500" > "cavium,smmu-v2" > - "qcom,<soc>-smmu-v2", "qcom,smmu-v2" > + "qcom,smmu-v2" > > depending on the particular implementation and/or the > version of the architecture implemented. > > - A number of Qcom SoCs use qcom,smmu-v2 version of the IP. > - "qcom,<soc>-smmu-v2" represents a soc specific compatible > - string that should be present along with the "qcom,smmu-v2" > - to facilitate SoC specific clocks/power connections and to > - address specific bug fixes. > - '<soc>' string in "qcom,<soc>-smmu-v2" should be one of the > - following: > - msm8996 - for msm8996 Qcom SoC. > - sdm845 - for sdm845 Qcom Soc. > - > - An example string would be - > - "qcom,msm8996-smmu-v2", "qcom,smmu-v2". > + Qcom SoCs using qcom,smmu-v2 must have soc specific > + compatible string attached to "qcom,smmu-v2" to take care > + of SoC specific clocks/power connections and to address > + specific bug fixes. > + Precisely, it should be one of the following: > + "qcom,msm8996-smmu-v2", "qcom,smmu-v2", > + "qcom,sdm845-smmu-v2", "qcom,smmu-v2". We don't need an explanation of why we need specific compatibles in each binding document (though maybe we need a better explanation somewhere). We just need to know what are valid values for compatibles and this includes any combinations. Generally, this is just a list of combinations. The Renesas folks have figured out how to do this and they have lots of SoCs. Yes, it makes for a lot of patches, but they are all mostly 1 liners and are dead simple to review. With QCom, I'm tired of having the same damn discussion with every new binding. Rob
