100 lines
2.8 KiB
YAML
100 lines
2.8 KiB
YAML
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# SPDX-License-Identifier: GPL-2.0
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/iommu/samsung,sysmmu.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: Samsung Exynos IOMMU H/W, System MMU (System Memory Management Unit)
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maintainers:
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- Marek Szyprowski <m.szyprowski@samsung.com>
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description: |+
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Samsung's Exynos architecture contains System MMUs that enables scattered
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physical memory chunks visible as a contiguous region to DMA-capable peripheral
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devices like MFC, FIMC, FIMD, GScaler, FIMC-IS and so forth.
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System MMU is an IOMMU and supports identical translation table format to
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ARMv7 translation tables with minimum set of page properties including access
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permissions, shareability and security protection. In addition, System MMU has
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another capabilities like L2 TLB or block-fetch buffers to minimize translation
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latency.
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System MMUs are in many to one relation with peripheral devices, i.e. single
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peripheral device might have multiple System MMUs (usually one for each bus
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master), but one System MMU can handle transactions from only one peripheral
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device. The relation between a System MMU and the peripheral device needs to be
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defined in device node of the peripheral device.
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MFC in all Exynos SoCs and FIMD, M2M Scalers and G2D in Exynos5420 has 2 System
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MMUs.
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* MFC has one System MMU on its left and right bus.
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* FIMD in Exynos5420 has one System MMU for window 0 and 4, the other system MMU
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for window 1, 2 and 3.
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* M2M Scalers and G2D in Exynos5420 has one System MMU on the read channel and
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the other System MMU on the write channel.
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For information on assigning System MMU controller to its peripheral devices,
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see generic IOMMU bindings.
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properties:
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compatible:
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const: samsung,exynos-sysmmu
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reg:
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maxItems: 1
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interrupts:
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maxItems: 1
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clocks:
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minItems: 1
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maxItems: 2
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clock-names:
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oneOf:
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- items:
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- const: sysmmu
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- items:
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- const: sysmmu
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- const: master
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- items:
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- const: aclk
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- const: pclk
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"#iommu-cells":
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const: 0
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power-domains:
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description: |
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Required if the System MMU is needed to gate its power.
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Please refer to the following document:
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Documentation/devicetree/bindings/power/pd-samsung.yaml
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maxItems: 1
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required:
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- compatible
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- reg
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- interrupts
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- clocks
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- clock-names
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- "#iommu-cells"
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additionalProperties: false
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examples:
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- |
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#include <dt-bindings/clock/exynos5250.h>
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sysmmu_gsc0: iommu@13e80000 {
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compatible = "samsung,exynos-sysmmu";
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reg = <0x13E80000 0x1000>;
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interrupt-parent = <&combiner>;
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interrupts = <2 0>;
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clock-names = "sysmmu", "master";
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clocks = <&clock CLK_SMMU_GSCL0>,
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<&clock CLK_GSCL0>;
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power-domains = <&pd_gsc>;
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#iommu-cells = <0>;
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};
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