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