Based on kernel version 4.16.1. Page generated on 2018-04-09 11:52 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";