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Documentation / devicetree / bindings / dma / shdma.txt




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Based on kernel version 3.16. Page generated on 2014-08-06 21:36 EST.

1	* SHDMA Device Tree bindings
2	
3	Sh-/r-mobile and r-car systems often have multiple identical DMA controller
4	instances, capable of serving any of a common set of DMA slave devices, using
5	the same configuration. To describe this topology we require all compatible
6	SHDMA DT nodes to be placed under a DMA multiplexer node. All such compatible
7	DMAC instances have the same number of channels and use the same DMA
8	descriptors. Therefore respective DMA DT bindings can also all be placed in the
9	multiplexer node. Even if there is only one such DMAC instance on a system, it
10	still has to be placed under such a multiplexer node.
11	
12	* DMA multiplexer
13	
14	Required properties:
15	- compatible:	should be "renesas,shdma-mux"
16	- #dma-cells:	should be <1>, see "dmas" property below
17	
18	Optional properties (currently unused):
19	- dma-channels:	number of DMA channels
20	- dma-requests:	number of DMA request signals
21	
22	* DMA controller
23	
24	Required properties:
25	- compatible:	should be of the form "renesas,shdma-<soc>", where <soc> should
26			be replaced with the desired SoC model, e.g.
27			"renesas,shdma-r8a73a4" for the system DMAC on r8a73a4 SoC
28	
29	Example:
30		dmac: dma-multiplexer@0 {
31			compatible = "renesas,shdma-mux";
32			#dma-cells = <1>;
33			dma-channels = <20>;
34			dma-requests = <256>;
35			#address-cells = <2>;
36			#size-cells = <2>;
37			ranges;
38	
39			dma0: dma-controller@e6700020 {
40				compatible = "renesas,shdma-r8a73a4";
41				reg = <0 0xe6700020 0 0x89e0>;
42				interrupt-parent = <&gic>;
43				interrupts = <0 220 4
44						0 200 4
45						0 201 4
46						0 202 4
47						0 203 4
48						0 204 4
49						0 205 4
50						0 206 4
51						0 207 4
52						0 208 4
53						0 209 4
54						0 210 4
55						0 211 4
56						0 212 4
57						0 213 4
58						0 214 4
59						0 215 4
60						0 216 4
61						0 217 4
62						0 218 4
63						0 219 4>;
64				interrupt-names = "error",
65						"ch0", "ch1", "ch2", "ch3",
66						"ch4", "ch5", "ch6", "ch7",
67						"ch8", "ch9", "ch10", "ch11",
68						"ch12", "ch13", "ch14", "ch15",
69						"ch16", "ch17", "ch18", "ch19";
70			};
71		};
72	
73	* DMA client
74	
75	Required properties:
76	- dmas:		a list of <[DMA multiplexer phandle] [MID/RID value]> pairs,
77			where MID/RID values are fixed handles, specified in the SoC
78			manual
79	- dma-names:	a list of DMA channel names, one per "dmas" entry
80	
81	Example:
82		dmas = <&dmac 0xd1
83			&dmac 0xd2>;
84		dma-names = "tx", "rx";
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