Documentation/devicetree/bindings/dma/shdma.txt

   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";