85 lines
2.2 KiB
Plaintext
85 lines
2.2 KiB
Plaintext
|
* 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";
|