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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/Documentation/devicetree/bindings/iommu/samsung,sysmmu.txt
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
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+Samsung Exynos IOMMU H/W, System MMU (System Memory Management Unit)
+
+Samsung's Exynos architecture contains System MMUs 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 an IOMMU and supports 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.
+
+System MMUs are in many to one relation with peripheral devices, i.e. single
+peripheral device might have multiple System MMUs (usually one for each bus
+master), but one System MMU can handle transactions from only one peripheral
+device. The relation between a System MMU and the peripheral device needs to be
+defined in device node of the peripheral device.
+
+MFC in all Exynos SoCs and FIMD, M2M Scalers and G2D in Exynos5420 has 2 System
+MMUs.
+* MFC has one System MMU on its left and right bus.
+* FIMD in Exynos5420 has one System MMU for window 0 and 4, the other system MMU
+ for window 1, 2 and 3.
+* M2M Scalers and G2D in Exynos5420 has one System MMU on the read channel and
+ the other System MMU on the write channel.
+The drivers must consider how to handle those System MMUs. One of the idea is
+to implement child devices or sub-devices which are the client devices of the
+System MMU.
+
+Note:
+The current DT binding for the Exynos System MMU is incomplete.
+The following properties can be removed or changed, if found incompatible with
+the "Generic IOMMU Binding" support for attaching devices to the IOMMU.
+
+Required properties:
+- compatible: Should be "samsung,exynos-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: An interrupt specifier for interrupt signal of System MMU,
+ according to the format defined by a particular interrupt
+ controller.
+- clock-names: Should be "sysmmu" if the System MMU is needed to gate its clock.
+ Optional "master" if the clock to the System MMU is gated by
+ another gate clock other than "sysmmu".
+ Exynos4 SoCs, there needs no "master" clock.
+ Exynos5 SoCs, some System MMUs must have "master" clocks.
+- clocks: Required if the System MMU is needed to gate its clock.
+- power-domains: 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
+
+Examples:
+ gsc_0: gsc@13e00000 {
+ compatible = "samsung,exynos5-gsc";
+ reg = <0x13e00000 0x1000>;
+ interrupts = <0 85 0>;
+ power-domains = <&pd_gsc>;
+ clocks = <&clock CLK_GSCL0>;
+ clock-names = "gscl";
+ };
+
+ sysmmu_gsc0: sysmmu@13E80000 {
+ compatible = "samsung,exynos-sysmmu";
+ reg = <0x13E80000 0x1000>;
+ interrupt-parent = <&combiner>;
+ interrupts = <2 0>;
+ clock-names = "sysmmu", "master";
+ clocks = <&clock CLK_SMMU_GSCL0>, <&clock CLK_GSCL0>;
+ power-domains = <&pd_gsc>;
+ };