Re: [PATCH V2 1/3] Documentation for system mmu in hi6220 platform.

[Rob Herring <robh+dt@kernel.org>]

On Tue, Oct 20, 2015 at 3:45 AM, Chen Feng <puck.chen@hisilicon.com> wrote:
> docs: iommu: Documentation for smmu in hi6220 SoC.
>
> Signed-off-by: Chen Feng <puck.chen@hisilicon.com>
> Signed-off-by: Yu Dongbin <yudongbin@hisilicon.com>
> ---
>  .../bindings/iommu/hisi,hi6220-iommu.txt           | 52 ++++++++++++++++++++++
>  1 file changed, 52 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iommu/hisi,hi6220-iommu.txt
>
> diff --git a/Documentation/devicetree/bindings/iommu/hisi,hi6220-iommu.txt b/Documentation/devicetree/bindings/iommu/hisi,hi6220-iommu.txt
> new file mode 100644
> index 0000000..93e0701
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iommu/hisi,hi6220-iommu.txt
> @@ -0,0 +1,52 @@
> +Hi6220 SoC SMMU Device Driver devicetree document
> +=======================================================================
> +The Architecture of SMMU on Hi6220 SoC:
> +
> +   +------------------------------------------------------------------+
> +   |                                                                  |
> +   |         +---------+  +--------+  +-------------+   +-------+     |
> +   |         |   ADE   |  |  ISP   |  |  V/J codec  |   |  G3D  |     |
> +   |         +----|----+  +---|----+  +------|------+   +---|---|     |
> +   |              |           |              |              |         |
> +   |     ---------v-----------v--------------v--------------v-----    |
> +   |                           Media Bus                              |
> +   |     --------------------------------|---------------|--------    |
> +   |                                     |               |            |
> +   |                                 +---v---------------v--------+   |
> +   |                                 |            SMMU            |   |
> +   |                                 +----------|---------|-------+   |
> +   |                                            |         |           |
> +   +--------------------------------------------|---------|-----------+
> +                                                |         |
> +                                   +------------v---------v-----------+
> +                                   |              DDRC                |
> +                                   +----------------------------------+

Nice diagram.

> +
> +Note:
> +The media system shared the same smmu IP. to access DDR memory. And all
> +media IP used the same page table.
> +
> +Below binding describes the system mmu for media system in hi6220 platform
> +
> +Required properties:
> +- compatible: Should be "hisilicon,hi6220-smmu" example:
> +               compatible = "hisilicon,hi6220-smmu";
> +- reg: A tuple of base address and size of System MMU registers.
> +- interrupts: An interrupt specifier for interrupt signal of System MMU.
> +- clocks: The clock used for smmu IP.
> +- clock-names: The name to enable clock with clock framework.
> +- #iommu-cells: The iommu-cells should be 1 for muti-master to use.
> +
> +Examples:
> +       smmu@f4210000 {

node name should be iommu.

> +               compatible = "hisilicon,hi6220-smmu";
> +               reg = <0x0 0xf4210000 0x0 0x1000>;
> +               interrupts = <GIC_SPI 113 IRQ_TYPE_LEVEL_HIGH>;
> +               clocks = <&sys_ctrl HI6220_MMU_CLK>,
> +                        <&media_ctrl HI6220_MED_MMU>,
> +                        <&sys_ctrl HI6220_MEDIA_PLL_SRC>;
> +               clock-names = "smmu_clk",
> +                             "media_sc_clk",
> +                             "smmu_peri_clk";
> +               #iommu-cells = <1>;
> +       };
> --
> 1.9.1
>