2019-08-29 22:46:56

by Krishna Reddy

[permalink] [raw]
Subject: [PATCH 6/7] arm64: tegra: Add DT node for T194 SMMU

Add DT node for T194 SMMU to enable SMMU support.

Signed-off-by: Krishna Reddy <[email protected]>
---
arch/arm64/boot/dts/nvidia/tegra194.dtsi | 75 ++++++++++++++++++++++++++++++++
1 file changed, 75 insertions(+)

diff --git a/arch/arm64/boot/dts/nvidia/tegra194.dtsi b/arch/arm64/boot/dts/nvidia/tegra194.dtsi
index d906958..ad509bb 100644
--- a/arch/arm64/boot/dts/nvidia/tegra194.dtsi
+++ b/arch/arm64/boot/dts/nvidia/tegra194.dtsi
@@ -1401,6 +1401,81 @@
0x82000000 0x0 0x40000000 0x1f 0x40000000 0x0 0xc0000000>; /* non-prefetchable memory (3GB) */
};

+ smmu: iommu@12000000 {
+ compatible = "nvidia,smmu-v2";
+ reg = <0 0x12000000 0 0x800000>,
+ <0 0x11000000 0 0x800000>,
+ <0 0x10000000 0 0x800000>;
+ interrupts = <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 232 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 240 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>;
+ stream-match-mask = <0x7f80>;
+ #global-interrupts = <1>;
+ #iommu-cells = <1>;
+ };
+
sysram@40000000 {
compatible = "nvidia,tegra194-sysram", "mmio-sram";
reg = <0x0 0x40000000 0x0 0x50000>;
--
2.1.4


2019-08-30 12:11:36

by Mikko Perttunen

[permalink] [raw]
Subject: Re: [PATCH 6/7] arm64: tegra: Add DT node for T194 SMMU

On 30.8.2019 1.47, Krishna Reddy wrote:
> Add DT node for T194 SMMU to enable SMMU support.
>
> Signed-off-by: Krishna Reddy <[email protected]>
> ---
> arch/arm64/boot/dts/nvidia/tegra194.dtsi | 75 ++++++++++++++++++++++++++++++++
> 1 file changed, 75 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/nvidia/tegra194.dtsi b/arch/arm64/boot/dts/nvidia/tegra194.dtsi
> index d906958..ad509bb 100644
> --- a/arch/arm64/boot/dts/nvidia/tegra194.dtsi
> +++ b/arch/arm64/boot/dts/nvidia/tegra194.dtsi
> @@ -1401,6 +1401,81 @@
> 0x82000000 0x0 0x40000000 0x1f 0x40000000 0x0 0xc0000000>; /* non-prefetchable memory (3GB) */
> };
>
> + smmu: iommu@12000000 {
> + compatible = "nvidia,smmu-v2";

Should we have a compatibility string like "nvidia,tegra194-smmu" so
that we can have other chips with SMMUv2 that could be different?

Mikko

> + reg = <0 0x12000000 0 0x800000>,
> + <0 0x11000000 0 0x800000>,
> + <0 0x10000000 0 0x800000>;
> + interrupts = <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 232 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 240 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>;
> + stream-match-mask = <0x7f80>;
> + #global-interrupts = <1>;
> + #iommu-cells = <1>;
> + };
> +
> sysram@40000000 {
> compatible = "nvidia,tegra194-sysram", "mmio-sram";
> reg = <0x0 0x40000000 0x0 0x50000>;
>

2019-08-30 15:45:50

by Robin Murphy

[permalink] [raw]
Subject: Re: [PATCH 6/7] arm64: tegra: Add DT node for T194 SMMU

On 29/08/2019 23:47, Krishna Reddy wrote:
> Add DT node for T194 SMMU to enable SMMU support.
>
> Signed-off-by: Krishna Reddy <[email protected]>
> ---
> arch/arm64/boot/dts/nvidia/tegra194.dtsi | 75 ++++++++++++++++++++++++++++++++
> 1 file changed, 75 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/nvidia/tegra194.dtsi b/arch/arm64/boot/dts/nvidia/tegra194.dtsi
> index d906958..ad509bb 100644
> --- a/arch/arm64/boot/dts/nvidia/tegra194.dtsi
> +++ b/arch/arm64/boot/dts/nvidia/tegra194.dtsi
> @@ -1401,6 +1401,81 @@
> 0x82000000 0x0 0x40000000 0x1f 0x40000000 0x0 0xc0000000>; /* non-prefetchable memory (3GB) */
> };
>
> + smmu: iommu@12000000 {
> + compatible = "nvidia,smmu-v2";
> + reg = <0 0x12000000 0 0x800000>,
> + <0 0x11000000 0 0x800000>,
> + <0 0x10000000 0 0x800000>;
> + interrupts = <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 232 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 240 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>,
> + <GIC_SPI 170 IRQ_TYPE_LEVEL_HIGH>;
> + stream-match-mask = <0x7f80>;
> + #global-interrupts = <1>;

Shouldn't that be 3?

Robin.

> + #iommu-cells = <1>;
> + };
> +
> sysram@40000000 {
> compatible = "nvidia,tegra194-sysram", "mmio-sram";
> reg = <0x0 0x40000000 0x0 0x50000>;
>

2019-08-30 17:28:07

by Krishna Reddy

[permalink] [raw]
Subject: RE: [PATCH 6/7] arm64: tegra: Add DT node for T194 SMMU

>> + #global-interrupts = <1>;

>Shouldn't that be 3?

Interrupt line is shared between global and all context faults for each SMMU instance.
Nvidia implementation checks for both Global and context faults on each interrupt to an SMMU instance.
It can be either 1 or 3. If we make it 3, we need to add two more irq entries in node for context faults.
In the future, we can update arm-smmu.c to support shared interrupt line between global and all context faults.


-KR

2019-08-30 17:46:45

by Robin Murphy

[permalink] [raw]
Subject: Re: [PATCH 6/7] arm64: tegra: Add DT node for T194 SMMU

On 30/08/2019 18:25, Krishna Reddy wrote:
>>> + #global-interrupts = <1>;
>
>> Shouldn't that be 3?
>
> Interrupt line is shared between global and all context faults for each SMMU instance.
> Nvidia implementation checks for both Global and context faults on each interrupt to an SMMU instance.
> It can be either 1 or 3. If we make it 3, we need to add two more irq entries in node for context faults.

The number of global interrupts has never been related to the number of
context interrupts :/

> In the future, we can update arm-smmu.c to support shared interrupt line between global and all context faults.

Clearly you have one combined interrupt output per SMMU - describing
those as one global interrupt and the first two context bank interrupts
respectively makes far less sense than calling them 3 global interrupts,
not least because the latter is strictly true. Yes, the binding prevents
us from describing the context bank interrupts for more than one
instance, but at that point the fact that it *is* the combined output
saves us - because the driver is aware of this specific integration it
knows it can just register the "secondary" global interrupts as
"secondary" context interrupts too. If we had separate IRQ lines per
context bank per instance, then we'd have a really big problem and might
have to redefine the binding, but as it is it happens to work out pretty
neatly.

Robin.

2019-08-30 18:36:44

by Krishna Reddy

[permalink] [raw]
Subject: RE: [PATCH 6/7] arm64: tegra: Add DT node for T194 SMMU

>The number of global interrupts has never been related to the number of context interrupts :/

Yeah, They are not related. I was trying to use minimum irq entries in the DT node as they both would achieve the same functionality.

>Clearly you have one combined interrupt output per SMMU - describing those as one global interrupt and the first two context bank interrupts respectively makes far less sense than calling them 3 global interrupts, not least because the latter is strictly true.

Will update to 3 in next patch to make it better for readability.

-KR

2019-08-30 18:41:10

by Krishna Reddy

[permalink] [raw]
Subject: RE: [PATCH 6/7] arm64: tegra: Add DT node for T194 SMMU

>> + smmu: iommu@12000000 {
>> + compatible = "nvidia,smmu-v2";

>Should we have a compatibility string like "nvidia,tegra194-smmu" so that we can have other chips with SMMUv2 that could be different?

As pointed by Robin as well, as Nvidia hasn't modified ARM MMU-500 implementation, we can update it to specific chip based.
Let me update.

-KR