diff mbox series

[v8,5/6] iommu/arm-smmu: Add support for qcom,smmu-v2 variant

Message ID 1518173826-11759-1-git-send-email-vivek.gautam@codeaurora.org
State Not Applicable, archived
Headers show
Series None | expand

Commit Message

Vivek Gautam Feb. 9, 2018, 10:57 a.m. UTC
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@codeaurora.org>
Reviewed-by: Rob Herring <robh@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(+)

Comments

Tomasz Figa Feb. 13, 2018, 8:57 a.m. UTC | #1
Hi Vivek,

Thanks for the patch. Please see my comments inline.

On Fri, Feb 9, 2018 at 7:57 PM, Vivek Gautam
<vivek.gautam@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.gautam@codeaurora.org>
> Reviewed-by: Rob Herring <robh@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
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diff mbox series

Patch

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".
+
 - 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.
+
+- 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 +163,20 @@  conditions.
                 iommu-map = <0 &smmu3 0 0x400>;
                 ...
         };
+
+	/* Qcom's arm,smmu-v2 implementation */
+	smmu4: iommu {
+		compatible = "qcom,msm8996-smmu-v2", "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 c7e924d553bd..40da3f251acf 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 {
@@ -1950,6 +1951,17 @@  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 },
@@ -1957,6 +1969,7 @@  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);
@@ -2319,6 +2332,7 @@  static int __maybe_unused arm_smmu_runtime_suspend(struct device *dev)
 IOMMU_OF_DECLARE(arm_mmu401, "arm,mmu-401");
 IOMMU_OF_DECLARE(arm_mmu500, "arm,mmu-500");
 IOMMU_OF_DECLARE(cavium_smmuv2, "cavium,smmu-v2");
+IOMMU_OF_DECLARE(qcom_smmuv2, "qcom,smmu-v2");
 
 MODULE_DESCRIPTION("IOMMU API for ARM architected SMMU implementations");
 MODULE_AUTHOR("Will Deacon <will.deacon@arm.com>");