* Hiroshi Doyu wrote:
> From: Hiroshi DOYU <hdoyu@xxxxxxxxxx>
>
> Add device tree support for Tegra30 IOMMU(SMMU).
>
> Signed-off-by: Hiroshi DOYU <hdoyu@xxxxxxxxxx>
> ---
> .../devicetree/bindings/arm/tegra/tegra30-smmu.txt | 19 +++++++++++++++++++
> arch/arm/boot/dts/tegra30.dtsi | 10 ++++++++++
> 2 files changed, 29 insertions(+), 0 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/arm/tegra/tegra30-smmu.txt b/Documentation/devicetree/bindings/arm/tegra/tegra30-smmu.txt
> new file mode 100644
> index 0000000..4bd8cd0
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/arm/tegra/tegra30-smmu.txt
> @@ -0,0 +1,19 @@
> +NVIDIA Tegra 30 IOMMU H/W, SMMU (System Memory Management Unit)
> +
> +Required properties:
> +- compatible : "nvidia,tegra30-smmu"
> +- reg : Should contain MC registers location and length
> +- reg : Should contain AHB Arbitration registers and length
> +- reg : Should contain virtual address space range
> +- interrupts : Should contain MC General interrupt
> +
> +Example:
> + smmu: smmu@7000f000 {
> + compatible = "nvidia,tegra30-smmu";
> + reg = < 0x7000f000 0x400 /* controller registers */
> + 0x6000c000 0x150 /* AHB Arbitration registers */
> + 0x00001000 0x3ffff000 >;/* Virtual address space range
> + * Exclude the 1st & last page
> + */
> + interrupts = < 0 13 0x40 >;
> + };
> diff --git a/arch/arm/boot/dts/tegra30.dtsi b/arch/arm/boot/dts/tegra30.dtsi
> index 62a7b39..c640a5b 100644
> --- a/arch/arm/boot/dts/tegra30.dtsi
> +++ b/arch/arm/boot/dts/tegra30.dtsi
> @@ -183,4 +183,14 @@
> reg = < 0x70000868 0xd0 /* Pad control registers */
> 0x70003000 0x3e0 >; /* Mux registers */
> };
> +
> + smmu: smmu@7000f000 {
> + compatible = "nvidia,tegra30-smmu";
> + reg = < 0x7000f000 0x400 /* controller registers */
> + 0x6000c000 0x150 /* AHB Arbitration registers */
> + 0x00001000 0x3ffff000 >;/* Virtual address space range
> + * Exclude the 1st & last page
> + */
> + interrupts = < 0 13 0x40 >;
> + };
> };
Why is the virtual address space range limited to 1 GiB? What is the reason
for the exclusion of the first and last pages?
Thierry
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