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SubjectRe: [PATCH] dt-bindings: arm: samsung: Convert Samsung Exynos IOMMU H/W, System MMU to dt-schema
On Mon, 9 Sep 2019 at 14:42, Maciej Falkowski <m.falkowski@samsung.com> wrote:
>
> Convert Samsung Exynos IOMMU H/W, System Memory Management Unit
> to newer dt-schema format.
>
> Signed-off-by: Maciej Falkowski <m.falkowski@samsung.com>
> Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>

Hi Maciej,

Thanks for the patch. Few comments below.

> ---
> .../bindings/iommu/samsung,sysmmu.txt | 67 ------------
> .../bindings/iommu/samsung,sysmmu.yaml | 102 ++++++++++++++++++
> 2 files changed, 102 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.txt b/Documentation/devicetree/bindings/iommu/samsung,sysmmu.txt
> deleted file mode 100644
> index 525ec82615a6..000000000000
> --- a/Documentation/devicetree/bindings/iommu/samsung,sysmmu.txt
> +++ /dev/null
> @@ -1,67 +0,0 @@
> -Samsung Exynos IOMMU H/W, System MMU (System Memory Management Unit)
> -
> -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.
> -
> -Required properties:
> -- compatible: Should be "samsung,exynos-sysmmu"
> -- reg: A tuple of base address and size of System MMU registers.
> -- #iommu-cells: Should be <0>.
> -- interrupts: An interrupt specifier for interrupt signal of System MMU,
> - according to the format defined by a particular interrupt
> - controller.
> -- clock-names: Should be "sysmmu" or a pair of "aclk" and "pclk" to gate
> - SYSMMU core clocks.
> - Optional "master" if the clock to the System MMU is gated by
> - another gate clock other core (usually main gate clock
> - of peripheral device this SYSMMU belongs to).
> -- clocks: Phandles for respective clocks described by clock-names.
> -- power-domains: Required if the System MMU is needed to gate its power.
> - Please refer to the following document:
> - Documentation/devicetree/bindings/power/pd-samsung.txt
> -
> -Examples:
> - gsc_0: gsc@13e00000 {
> - compatible = "samsung,exynos5-gsc";
> - reg = <0x13e00000 0x1000>;
> - interrupts = <0 85 0>;
> - power-domains = <&pd_gsc>;
> - clocks = <&clock CLK_GSCL0>;
> - clock-names = "gscl";
> - iommus = <&sysmmu_gsc0>;
> - };
> -
> - sysmmu_gsc0: sysmmu@13e80000 {
> - compatible = "samsung,exynos-sysmmu";
> - reg = <0x13E80000 0x1000>;
> - interrupt-parent = <&combiner>;
> - interrupts = <2 0>;
> - clock-names = "sysmmu", "master";
> - clocks = <&clock CLK_SMMU_GSCL0>, <&clock CLK_GSCL0>;
> - power-domains = <&pd_gsc>;
> - #iommu-cells = <0>;
> - };
> diff --git a/Documentation/devicetree/bindings/iommu/samsung,sysmmu.yaml b/Documentation/devicetree/bindings/iommu/samsung,sysmmu.yaml
> new file mode 100644
> index 000000000000..6c40dfb86899
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iommu/samsung,sysmmu.yaml
> @@ -0,0 +1,102 @@
> +# 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

Add empty line between properties. Makes it easier to read.

> + reg:
> + description: A tuple of base address and size of System MMU registers.

Description not needed.

> + maxItems: 1
> + interrupts:
> + description: |
> + An interrupt specifier for interrupt signal of System MMU,
> + according to the format defined by a particular interrupt
> + controller.

Description not needed.

> + clocks:
> + description: Phandles for respective clocks described by clock-names.

Description not needed but I think number of elements is.

> + clock-names:
> + description: |
> + Should be "sysmmu" or a pair of "aclk" and "pclk" to gate
> + SYSMMU core clocks.
> + Optional "master" if the clock to the System MMU is gated by
> + another gate clock other core (usually main gate clock
> + of peripheral device this SYSMMU belongs to).
> + minItems: 1
> + maxItems: 2

Based on the description this can be up to three clocks.

Please declare the exact items within each combination (so either
sysmmu or aclk+pclk, plus optional master?). If this does not depend
on compatible, then oneOf could work. Then number of items could be
removed.

> + "#iommu-cells":
> + const: 0
> + description: Should be <0>.

Description not needed.

> + power-domains:

$ref: /schemas/types.yaml#/definitions/phandle

> + 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

Missing space after //

> + clock-names = "gscl";
> + iommus = <&sysmmu_gsc0>;
> + };
> + - |

This is one example, not two.

Best regards,
Krzysztof

> + sysmmu_gsc0: sysmmu@13e80000 {
> + 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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