Hi Vivek, Thanks for the patch. Please see my comments inline.
On Fri, Feb 9, 2018 at 7:57 PM, Vivek Gautam <vivek.gau...@codeaurora.org> wrote: > qcom,smmu-v2 is an arm,smmu-v2 implementation with specific > clock and power requirements. This smmu core is used with > multiple masters on msm8996, viz. mdss, video, etc. > Add bindings for the same. > > Signed-off-by: Vivek Gautam <vivek.gau...@codeaurora.org> > Reviewed-by: Rob Herring <r...@kernel.org> > --- > > Changes in v8: > - Added the missing IOMMU_OF_DECLARE declaration for "qcom,smmu-v2" > > .../devicetree/bindings/iommu/arm,smmu.txt | 43 > ++++++++++++++++++++++ > drivers/iommu/arm-smmu.c | 14 +++++++ > 2 files changed, 57 insertions(+) > > diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.txt > b/Documentation/devicetree/bindings/iommu/arm,smmu.txt > index 8a6ffce12af5..169222ae2706 100644 > --- a/Documentation/devicetree/bindings/iommu/arm,smmu.txt > +++ b/Documentation/devicetree/bindings/iommu/arm,smmu.txt > @@ -17,10 +17,19 @@ conditions. > "arm,mmu-401" > "arm,mmu-500" > "cavium,smmu-v2" > + "qcom,<soc>-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. > + An example string would be - > + "qcom,msm8996-smmu-v2", "qcom,smmu-v2". Hmm, I remember that for <soc> and similar wildcards we required explicitly listing allowed values. Rob, has it changed since I stumbled upon such thing last time (or I just got it wrong before)? > + > - reg : Base address and size of the SMMU. > > - #global-interrupts : The number of global interrupts exposed by the > @@ -71,6 +80,23 @@ conditions. > or using stream matching with #iommu-cells = <2>, and > may be ignored if present in such cases. > > +- clock-names: Should be "bus", and "iface" for "qcom,smmu-v2" > + implementation. > + > + "bus" clock for "qcom,smmu-v2" is required for downstream > + bus access and for the smmu ptw. > + > + "iface" clock is required to access smmu's registers > through > + the TCU's programming interface. nit: Could we have it in a bit more structured way? E.g. - clock-names: List of names of clocks input to the device. The required list depends on particular implementation and is as follows: - for "qcom,smmu-v2": - "bus": clock required for downstream bus access and for the smmu ptw, - "iface": clock required to access smmu's registers through the TCU's programming interface. - unspecified for other implementations. (+/- wrapping) > + > +- clocks: Phandles for respective clocks described by clock-names. Phandle is just a pointer to another node. Clocks are however specified using a phandle and a number of arguments, depending on the clock controller. I'd change it to: - clocks: Specifiers for all clocks listed in the clock-names property, as per generic clock bindings. > + > +- power-domains: Phandles to SMMU's power domain specifier. This is > + required even if SMMU belongs to the master's power > + domain, as the SMMU will have to be enabled and > + accessed before master gets enabled and linked to its > + SMMU. >From DT point of view, the relationship of SMMU belonging to a master device doesn't exist. The power-domains property needs to be properly specified for all devices within power domains represented in DT, with an exception of the case when the parent-child relationship is explicitly stated in DT by child devices being represented by child nodes of the parent device node. - power-domains: Specifiers for power domains required to be powered on for the SMMU to operate, as per generic power domain bindings. Best regards, Tomasz