Kernel-4.18.0-80.el8_nbpfaxi

• Renesas “Type-AXI” NBPFAXI* DMA controllers

• DMA controller

Required properties

• compatible: must be one of

    "renesas,nbpfaxi64dmac1b4"
    "renesas,nbpfaxi64dmac1b8"
    "renesas,nbpfaxi64dmac1b16"
    "renesas,nbpfaxi64dmac4b4"
    "renesas,nbpfaxi64dmac4b8"
    "renesas,nbpfaxi64dmac4b16"
    "renesas,nbpfaxi64dmac8b4"
    "renesas,nbpfaxi64dmac8b8"
    "renesas,nbpfaxi64dmac8b16"
  

• #dma-cells: must be 2: the first integer is a terminal number, to which this

    slave is connected, the second one is flags. Flags is a bitmask
    with the following bits defined:
  

#define NBPF_SLAVE_RQ_HIGH 1
#define NBPF_SLAVE_RQ_LOW 2
#define NBPF_SLAVE_RQ_LEVEL 4

Optional properties:

• max-burst-mem-read: limit burst size for memory reads
  (DMA_MEM_TO_MEM/DMA_MEM_TO_DEV) to this value, specified in bytes, rather
  than using the maximum burst size allowed by the hardware’s buffer size.
• max-burst-mem-write: limit burst size for memory writes
  (DMA_DEV_TO_MEM/DMA_MEM_TO_MEM) to this value, specified in bytes, rather
  than using the maximum burst size allowed by the hardware’s buffer size.
  If both max-burst-mem-read and max-burst-mem-write are set, DMA_MEM_TO_MEM
  will use the lower value.

You can use dma-channels and dma-requests as described in dma.txt, although they
won’t be used, this information is derived from the compatibility string.

Example:

dma: dma-controller@48000000 {
    compatible = "renesas,nbpfaxi64dmac8b4";
    reg = <0x48000000 0x400>;
    interrupts = <0 12 0x4
              0 13 0x4
              0 14 0x4
              0 15 0x4
              0 16 0x4
              0 17 0x4
              0 18 0x4
              0 19 0x4>;
    #dma-cells = <2>;
    dma-channels = <8>;
    dma-requests = <8>;
};

• DMA client

Required properties:

dmas and dma-names are required, as described in dma.txt.

Example:

#include <dt-bindings/dma/nbpfaxi.h>

…
dmas = <&dma 0 (NBPF_SLAVE_RQ_HIGH | NBPF_SLAVE_RQ_LEVEL)
&dma 1 (NBPF_SLAVE_RQ_HIGH | NBPF_SLAVE_RQ_LEVEL)>;
dma-names = “rx”, “tx”;