On Monday, August 05, 2013 08:16:40 PM Cho KyongHo wrote: > > -----Original Message----- > > From: Bartlomiej Zolnierkiewicz [mailto:b.zolnier...@samsung.com] > > Sent: Saturday, August 03, 2013 2:14 AM > > > > Hi, > > > > On Friday, July 26, 2013 08:28:19 PM Cho KyongHo wrote: > > > Signed-off-by: Cho KyongHo <pullip....@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 > > > + > > > +Examples: > > > +A System MMU is dedicated to a single master device. > > > + gsc_0: gsc@0x13e00000 { > > > + compatible = "samsung,exynos5-gsc"; > > > + reg = <0x13e00000 0x1000>; > > > + interrupts = <0 85 0>; > > > + samsung,power-domain = <&pd_gsc>; > > > + clocks = <&clock 256>; > > > + clock-names = "gscl"; > > > + iommu = <&sysmmu_gsc1>; > > > + }; > > > + > > > + sysmmu_gsc0: sysmmu@13E80000 { > > > + compatible = "samsung,exynos4210-sysmmu"; > > > + reg = <0x13E80000 0x1000>; > > > + interrupt-parent = <&combiner>; > > > + interrupt-names = "sysmmu-gsc0"; > > > + interrupts = <2 0>; > > > + clock-names = "sysmmu", "master"; > > > + clocks = <&clock 262>, <&clock 256>; > > > + samsung,power-domain = <&pd_gsc>; > > > + status = "ok"; > > > + }; > > > + > > > +MFC has 2 System MMUs for each port that MFC is attached. Thus it seems > > > natural > > > +to define 2 System MMUs for each port of the MFC: > > > > Marek Szyprowski (added to cc:) has a patch fixing MFC to create separate > > mfc_l and mfc_r devices (like it was in the past). Using this patch it > > would be possible to bind sysmmu_mfc_l to mfc_l device and sysmmu_mfc_r to > > mfc_r device. This probably also requires adding some MFC specific handling > > in a device tree node and to the new master's device PM ops (in patch #10) > > as previously (in our trees) sysmmu_mfc r device was set as parent of > > sysmmu_mfc_l device which in turn was a parent for main MFC device (to make > > runtime Power Management work). However because MFC is the only device > > requiring use of multiple System MMUs above changes would allow us (unless > > I'm missing something?) to use just one System MMU device per struct > > exynos_iommu_client instance (making driver a lot simpler). > > > > Does it mean that we can make the exynos-iommu driver simpler > with Marek Szyprowski's patch?
I think so and you probably need to change MFC handling anyway because MFC driver does DMA allocations per mfc_l/mfc_r devices and not per main device (at least in the upstream kernels). [ Marek, could you please resfresh and post your patch on the list? ] BTW There is an additional problem with combining System MMU devices per one main device - it limits available address space (which in case of MFC is very limited by hardware design). > It is welcome but I don't think it covers all topologies of System MMU and > master H/W. Those are getting more complex. Could you please be more specific? I know about FIMC ISP subsystem but it doesn't require combining System MMUs. Are there any other examples of complex System MMU + master H/W topologies? Anyway I think that System MMUs should not be combined (as it is done in patch #10) and should be binded per "memport" devices and not per main device (as done in this patch). Best regards, -- Bartlomiej Zolnierkiewicz Samsung R&D Institute Poland Samsung Electronics -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
