[PATCH v8 06/12] ARM: dts: Add description of System MMU of Exynos SoCs

Cho KyongHo
2013-10-08T04:38:53Z

On Mon, 07 Oct 2013 08:44:54 -0500, Rob Herring wrote:
> On Fri, Jul 26, 2013 at 6:28 AM, Cho KyongHo <pullip.cho@samsung.com> wrote:
> > Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
> > ---
> > .../bindings/iommu/samsung,exynos4210-sysmmu.txt | 103 +++++++
> > arch/arm/boot/dts/exynos4.dtsi | 122 ++++++++
> > arch/arm/boot/dts/exynos4210.dtsi | 25 ++
> > arch/arm/boot/dts/exynos4x12.dtsi | 76 +++++
> > arch/arm/boot/dts/exynos5250.dtsi | 291 ++++++++++++++++++++
> > 5 files changed, 617 insertions(+), 0 deletions(-)
> > create mode 100644 Documentation/devicetree/bindings/iommu/samsung,exynos4210-sysmmu.txt
> >
> > diff --git a/Documentation/devicetree/bindings/iommu/samsung,exynos4210-sysmmu.txt
> > b/Documentation/devicetree/bindings/iommu/samsung,exynos4210-sysmmu.txt
> > new file mode 100644
> > index 0000000..92f0a33
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iommu/samsung,exynos4210-sysmmu.txt
> > @@ -0,0 +1,103 @@
> > +Samsung Exynos4210 IOMMU H/W, System MMU (System Memory Management Unit)
> > +
> > +Samsung's Exynos architecture contains System MMU 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 a sort of IOMMU and support 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.
> > +
> > +A System MMU is dedicated to a single master peripheral device. Thus, it is
> > +important to specify the correct System MMU in the device node of its master
> > +device. Whereas a System MMU is dedicated to a master device, the master device
> > +may have more than one System MMU.
> > +
> > +Required properties:
> > +- compatible: Should be "samsung,exynos4210-sysmmu"
> > +- reg: A tuple of base address and size of System MMU registers.
> > +- interrupt-parent: The phandle of the interrupt controller of System MMU
> > +- interrupts: A tuple of numbers that indicates the interrupt source.
> > +- clock-names: Should be "sysmmu" if the System MMU is needed to gate its clock.
> > + Please refer to the following documents:
> > + Documentation/devicetree/bindings/clock/clock-bindings.txt
> > + Documentation/devicetree/bindings/clock/exynos4-clock.txt
> > + Documentation/devicetree/bindings/clock/exynos5250-clock.txt
> > + Optional "master" if the clock to the System MMU is gated by
> > + another gate clock other than "sysmmu". The System MMU driver
> > + sets "master" the parent of "sysmmu".
> > + Exynos4 SoCs, there needs no "master" clocks.
> > + Exynos5 SoCs, some System MMUs must have "master" clocks.
> > +- clocks: Required if the System MMU is needed to gate its clock.
> > + Please refer to the documents listed above.
> > +- samsung,power-domain: Required if the System MMU is needed to gate its power.
> > + Please refer to the following document:
> > + Documentation/devicetree/bindings/arm/exynos/power_domain.txt
> > +
> > +Required properties for the master peripheral devices:
> > +- iommu: phandles to the System MMUs of the device
>
> You have not addressed my comments from the last version. We do not
> need 2 (or more) different ways to describe the connection between
> masters and iommu's. Use mmu-masters property here to describe the
> connection.
>

Sorry, I forgot to reply.
I just thought the meaning of your comment that it should be align with ARM System MMU.
I now understand and it should be changed to mmu-masters property
because it is now in the kernel.

Thank you.

> Rob