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SubjectRe: [PATCH v3] dt-bindings: arm: samsung: Convert Samsung Exynos IOMMU H/W, System MMU to dt-schema
On Wed, Sep 11, 2019 at 01:04:46PM +0200, Maciej Falkowski wrote:
> Convert Samsung Exynos IOMMU H/W, System Memory Management Unit
> to newer dt-schema format.
>
> Update clock description.
>
> Signed-off-by: Maciej Falkowski <m.falkowski@samsung.com>
> Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
> ---
> Hi Krzysztof,
>
> Thank you for feedback.
>
> v3:
>
> - remove obsolete interrupts description and
> set its maxItems to one. There are some incompatible
> files which will be fixed with another patch.
>
> - clock-names pattern is changed to your more precise
> version. I also added option "pclk" + "aclk" as some
> bindings are also using it.
>
> Best regards,
> Maciej Falkowski
> ---
> .../bindings/iommu/samsung,sysmmu.txt | 67 -----------
> .../bindings/iommu/samsung,sysmmu.yaml | 112 ++++++++++++++++++
> 2 files changed, 112 insertions(+), 67 deletions(-)
> delete mode 100644 Documentation/devicetree/bindings/iommu/samsung,sysmmu.txt
> create mode 100644 Documentation/devicetree/bindings/iommu/samsung,sysmmu.yaml


> diff --git a/Documentation/devicetree/bindings/iommu/samsung,sysmmu.yaml b/Documentation/devicetree/bindings/iommu/samsung,sysmmu.yaml
> new file mode 100644
> index 000000000000..a8141d6c326a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iommu/samsung,sysmmu.yaml
> @@ -0,0 +1,112 @@
> +# SPDX-License-Identifier: GPL-2.0
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iommu/samsung,sysmmu.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Samsung Exynos IOMMU H/W, System MMU (System Memory Management Unit)
> +
> +maintainers:
> + - Marek Szyprowski <m.szyprowski@samsung.com>
> +
> +description: |+
> + Samsung's Exynos architecture contains System MMUs that enables scattered
> + physical memory chunks visible as a contiguous region to DMA-capable peripheral
> + devices like MFC, FIMC, FIMD, GScaler, FIMC-IS and so forth.
> +
> + System MMU is an IOMMU and supports identical translation table format to
> + ARMv7 translation tables with minimum set of page properties including access
> + permissions, shareability and security protection. In addition, System MMU has
> + another capabilities like L2 TLB or block-fetch buffers to minimize translation
> + latency.
> +
> + System MMUs are in many to one relation with peripheral devices, i.e. single
> + peripheral device might have multiple System MMUs (usually one for each bus
> + master), but one System MMU can handle transactions from only one peripheral
> + device. The relation between a System MMU and the peripheral device needs to be
> + defined in device node of the peripheral device.
> +
> + MFC in all Exynos SoCs and FIMD, M2M Scalers and G2D in Exynos5420 has 2 System
> + MMUs.
> + * MFC has one System MMU on its left and right bus.
> + * FIMD in Exynos5420 has one System MMU for window 0 and 4, the other system MMU
> + for window 1, 2 and 3.
> + * M2M Scalers and G2D in Exynos5420 has one System MMU on the read channel and
> + the other System MMU on the write channel.
> +
> + For information on assigning System MMU controller to its peripheral devices,
> + see generic IOMMU bindings.
> +
> +properties:
> + compatible:
> + const: samsung,exynos-sysmmu
> +
> + reg:
> + maxItems: 1
> +
> + interrupts:
> + maxItems: 1
> +
> + clocks:
> + minItems: 1
> + maxItems: 2
> +
> + clock-names:
> + oneOf:
> + - items:
> + - const: sysmmu
> + - items:
> + - const: sysmmu
> + - const: master
> + - items:
> + - const: aclk
> + - const: pclk
> + - items:
> + - const: pclk
> + - const: aclk

Sigh. I'd prefer you fix the order in whichever case is less common.

> + description: |
> + Should be "sysmmu" with optional "master"
> + or a pair "aclk" with "pclk".

No need to describe what the schema already says.

> +
> + "#iommu-cells":
> + const: 0
> +
> + power-domains:
> + $ref: /schemas/types.yaml#/definitions/phandle

No need to define common property types.

Just 'maxItems: 1' is enough.

> + description: |
> + Required if the System MMU is needed to gate its power.
> + Please refer to the following document:
> + Documentation/devicetree/bindings/power/pd-samsung.txt
> +
> +required:
> + - compatible
> + - reg
> + - interrupts
> + - clocks
> + - clock-names
> + - "#iommu-cells"
> +
> +examples:
> + - |
> + gsc_0: gsc@13e00000 {
> + compatible = "samsung,exynos5-gsc";
> + reg = <0x13e00000 0x1000>;
> + interrupts = <0 85 0>;
> + power-domains = <&pd_gsc>;
> + clocks = <&clock 0>; // CLK_GSCL0
> + clock-names = "gscl";
> + iommus = <&sysmmu_gsc0>;
> + };
> +
> + sysmmu_gsc0: sysmmu@13e80000 {

This should be:

iommu@...

> + compatible = "samsung,exynos-sysmmu";
> + reg = <0x13E80000 0x1000>;
> + interrupt-parent = <&combiner>;
> + interrupts = <2 0>;
> + clock-names = "sysmmu", "master";
> + clocks = <&clock 0>, // CLK_SMMU_GSCL0
> + <&clock 0>; // CLK_GSCL0
> + power-domains = <&pd_gsc>;
> + #iommu-cells = <0>;
> + };
> +
> --
> 2.17.1
>

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