Kernel-4.18.0-80.el8_img-mdc-dma

published: updated: Kernel_4.18.0-80.el8_内核文档
  • IMG Multi-threaded DMA Controller (MDC)

Required properties:

  • compatible: Must be “img,pistachio-mdc-dma”.
  • reg: Must contain the base address and length of the MDC registers.
  • interrupts: Must contain all the per-channel DMA interrupts.
  • clocks: Must contain an entry for each entry in clock-names.
    See ../clock/clock-bindings.txt for details.
  • clock-names: Must include the following entries:
    • sys: MDC system interface clock.
  • img,cr-periph: Must contain a phandle to the peripheral control syscon
    node which contains the DMA request to channel mapping registers.
  • img,max-burst-multiplier: Must be the maximum supported burst size multiplier.
    The maximum burst size is this value multiplied by the hardware-reported bus
    width.
  • #dma-cells: Must be 3:
    • The first cell is the peripheral’s DMA request line.
    • The second cell is a bitmap specifying to which channels the DMA request
      line may be mapped (i.e. bit N set indicates channel N is usable).
    • The third cell is the thread ID to be used by the channel.

Optional properties:

  • dma-channels: Number of supported DMA channels, up to 32. If not specified
    the number reported by the hardware is used.

Example:

mdc: dma-controller@18143000 {
compatible = “img,pistachio-mdc-dma”;
reg = <0x18143000 0x1000>;
interrupts = <GIC_SHARED 27 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SHARED 28 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SHARED 29 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SHARED 30 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SHARED 31 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SHARED 32 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SHARED 33 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SHARED 34 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SHARED 35 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SHARED 36 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SHARED 37 IRQ_TYPE_LEVEL_HIGH>,
<GIC_SHARED 38 IRQ_TYPE_LEVEL_HIGH>;
clocks = <&system_clk>;
clock-names = “sys”;

img,max-burst-multiplier = <16>;
img,cr-periph = <&cr_periph>;

#dma-cells = <3>;

};

spi@18100f00 {
…
dmas = <&mdc 9 0xffffffff 0>, <&mdc 10 0xffffffff 0>;
dma-names = “tx”, “rx”;
…
};

oosTech by Sam Lee