Re: [PATCH v5 5/6] iommu/arm-smmu: Add support for qcom,smmu-v2 variant

[Rob Herring]

On Tue, Jan 09, 2018 at 03:31:48PM +0530, Vivek Gautam 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.gautam@xxxxxxxxxxxxxx>
> ---
> 
>  * Major change in this patch -
>    Changed compatible string from 'qcom,msm8996-smmu-v2' to
>    'qcom,smmu-v2' to reflect the IP version rather than the
>    platform on which it is used.

The bugs and how things are connected are all the same? I'd suggest you 
keep both strings.

>    The same IP is used across multiple platforms including msm8996,
>    and sdm845 etc.

But for only 2 or so platforms a fallback is not really worth it. You'll 
probably be on SMMUv3 before too long...

> 
>  .../devicetree/bindings/iommu/arm,smmu.txt         | 35 ++++++++++++++++++++++
>  drivers/iommu/arm-smmu.c                           | 13 ++++++++
>  2 files changed, 48 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.txt b/Documentation/devicetree/bindings/iommu/arm,smmu.txt
> index 8a6ffce12af5..e4951288c87c 100644
> --- a/Documentation/devicetree/bindings/iommu/arm,smmu.txt
> +++ b/Documentation/devicetree/bindings/iommu/arm,smmu.txt
> @@ -17,6 +17,7 @@ conditions.
>                          "arm,mmu-401"
>                          "arm,mmu-500"
>                          "cavium,smmu-v2"
> +                        "qcom,smmu-v2"
>  
>                    depending on the particular implementation and/or the
>                    version of the architecture implemented.
> @@ -71,6 +72,23 @@ 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.
> +
> +- clocks:         Phandles for respective clocks described by clock-names.
> +
> +- 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.
> +
>  ** Deprecated properties:
>  
>  - mmu-masters (deprecated in favour of the generic "iommus" binding) :
> @@ -137,3 +155,20 @@ conditions.
>                  iommu-map = <0 &smmu3 0 0x400>;
>                  ...
>          };
> +
> +	/* Qcom's arm,smmu-v2 implementation */
> +	smmu4: iommu {
> +		compatible = "qcom,smmu-v2";
> +		reg = <0xd00000 0x10000>;
> +
> +		#global-interrupts = <1>;
> +		interrupts = <GIC_SPI 73 IRQ_TYPE_LEVEL_HIGH>,
> +			     <GIC_SPI 320 IRQ_TYPE_LEVEL_HIGH>,
> +			     <GIC_SPI 321 IRQ_TYPE_LEVEL_HIGH>;
> +		#iommu-cells = <1>;
> +		power-domains = <&mmcc MDSS_GDSC>;
> +
> +		clocks = <&mmcc SMMU_MDP_AXI_CLK>,
> +			 <&mmcc SMMU_MDP_AHB_CLK>;
> +		clock-names = "bus", "iface";
> +	};
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index 33bbcfedb896..2ade214c41bc 100644
> --- a/drivers/iommu/arm-smmu.c
> +++ b/drivers/iommu/arm-smmu.c
> @@ -119,6 +119,7 @@ enum arm_smmu_implementation {
>  	GENERIC_SMMU,
>  	ARM_MMU500,
>  	CAVIUM_SMMUV2,
> +	QCOM_SMMUV2,
>  };
>  
>  struct arm_smmu_s2cr {
> @@ -1971,6 +1972,17 @@ struct arm_smmu_match_data {
>  ARM_SMMU_MATCH_DATA(arm_mmu500, ARM_SMMU_V2, ARM_MMU500);
>  ARM_SMMU_MATCH_DATA(cavium_smmuv2, ARM_SMMU_V2, CAVIUM_SMMUV2);
>  
> +static const char * const qcom_smmuv2_clks[] = {
> +	"bus", "iface",
> +};
> +
> +static const struct arm_smmu_match_data qcom_smmuv2 = {
> +	.version = ARM_SMMU_V2,
> +	.model = QCOM_SMMUV2,
> +	.clks = qcom_smmuv2_clks,
> +	.num_clks = ARRAY_SIZE(qcom_smmuv2_clks),
> +};
> +
>  static const struct of_device_id arm_smmu_of_match[] = {
>  	{ .compatible = "arm,smmu-v1", .data = &smmu_generic_v1 },
>  	{ .compatible = "arm,smmu-v2", .data = &smmu_generic_v2 },
> @@ -1978,6 +1990,7 @@ struct arm_smmu_match_data {
>  	{ .compatible = "arm,mmu-401", .data = &arm_mmu401 },
>  	{ .compatible = "arm,mmu-500", .data = &arm_mmu500 },
>  	{ .compatible = "cavium,smmu-v2", .data = &cavium_smmuv2 },
> +	{ .compatible = "qcom,smmu-v2", .data = &qcom_smmuv2 },
>  	{ },
>  };
>  MODULE_DEVICE_TABLE(of, arm_smmu_of_match);
> -- 
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