Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / Documentation / devicetree / bindings / dma / shdma.txt

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+* SHDMA Device Tree bindings
+
+Sh-/r-mobile and r-car systems often have multiple identical DMA controller
+instances, capable of serving any of a common set of DMA slave devices, using
+the same configuration. To describe this topology we require all compatible
+SHDMA DT nodes to be placed under a DMA multiplexer node. All such compatible
+DMAC instances have the same number of channels and use the same DMA
+descriptors. Therefore respective DMA DT bindings can also all be placed in the
+multiplexer node. Even if there is only one such DMAC instance on a system, it
+still has to be placed under such a multiplexer node.
+
+* DMA multiplexer
+
+Required properties:
+- compatible:  should be "renesas,shdma-mux"
+- #dma-cells:  should be <1>, see "dmas" property below
+
+Optional properties (currently unused):
+- dma-channels:        number of DMA channels
+- dma-requests:        number of DMA request signals
+
+* DMA controller
+
+Required properties:
+- compatible:  should be of the form "renesas,shdma-<soc>", where <soc> should
+               be replaced with the desired SoC model, e.g.
+               "renesas,shdma-r8a73a4" for the system DMAC on r8a73a4 SoC
+
+Example:
+       dmac: dma-multiplexer@0 {
+               compatible = "renesas,shdma-mux";
+               #dma-cells = <1>;
+               dma-channels = <20>;
+               dma-requests = <256>;
+               #address-cells = <2>;
+               #size-cells = <2>;
+               ranges;
+
+               dma0: dma-controller@e6700020 {
+                       compatible = "renesas,shdma-r8a73a4";
+                       reg = <0 0xe6700020 0 0x89e0>;
+                       interrupt-parent = <&gic>;
+                       interrupts = <0 220 4
+                                       0 200 4
+                                       0 201 4
+                                       0 202 4
+                                       0 203 4
+                                       0 204 4
+                                       0 205 4
+                                       0 206 4
+                                       0 207 4
+                                       0 208 4
+                                       0 209 4
+                                       0 210 4
+                                       0 211 4
+                                       0 212 4
+                                       0 213 4
+                                       0 214 4
+                                       0 215 4
+                                       0 216 4
+                                       0 217 4
+                                       0 218 4
+                                       0 219 4>;
+                       interrupt-names = "error",
+                                       "ch0", "ch1", "ch2", "ch3",
+                                       "ch4", "ch5", "ch6", "ch7",
+                                       "ch8", "ch9", "ch10", "ch11",
+                                       "ch12", "ch13", "ch14", "ch15",
+                                       "ch16", "ch17", "ch18", "ch19";
+               };
+       };
+
+* DMA client
+
+Required properties:
+- dmas:                a list of <[DMA multiplexer phandle] [MID/RID value]> pairs,
+               where MID/RID values are fixed handles, specified in the SoC
+               manual
+- dma-names:   a list of DMA channel names, one per "dmas" entry
+
+Example:
+       dmas = <&dmac 0xd1
+               &dmac 0xd2>;
+       dma-names = "tx", "rx";