xref: /freebsd/sys/contrib/device-tree/Bindings/dma/snps-dma.txt (revision c66ec88f)

* Synopsys Designware DMA Controller

Required properties:
- compatible: "snps,dma-spear1340"
- reg: Address range of the DMAC registers
- interrupt: Should contain the DMAC interrupt number
- dma-channels: Number of channels supported by hardware
- dma-requests: Number of DMA request lines supported, up to 16
- dma-masters: Number of AHB masters supported by the controller
- #dma-cells: must be <3>
- chan_allocation_order: order of allocation of channel, 0 (default): ascending,
  1: descending
- chan_priority: priority of channels. 0 (default): increase from chan 0->n, 1:
  increase from chan n->0
- block_size: Maximum block size supported by the controller
- data-width: Maximum data width supported by hardware per AHB master
  (in bytes, power of 2)


Deprecated properties:
- data_width: Maximum data width supported by hardware per AHB master
  (0 - 8bits, 1 - 16bits, ..., 5 - 256bits)


Optional properties:
- multi-block: Multi block transfers supported by hardware. Array property with
  one cell per channel. 0: not supported, 1 (default): supported.
- snps,dma-protection-control: AHB HPROT[3:1] protection setting.
  The default value is 0 (for non-cacheable, non-buffered,
  unprivileged data access).
  Refer to include/dt-bindings/dma/dw-dmac.h for possible values.

Example:

	dmahost: dma@fc000000 {
		compatible = "snps,dma-spear1340";
		reg = <0xfc000000 0x1000>;
		interrupt-parent = <&vic1>;
		interrupts = <12>;

		dma-channels = <8>;
		dma-requests = <16>;
		dma-masters = <2>;
		#dma-cells = <3>;
		chan_allocation_order = <1>;
		chan_priority = <1>;
		block_size = <0xfff>;
		data-width = <8 8>;
	};

DMA clients connected to the Designware DMA controller must use the format
described in the dma.txt file, using a four-cell specifier for each channel.
The four cells in order are:

1. A phandle pointing to the DMA controller
2. The DMA request line number
3. Memory master for transfers on allocated channel
4. Peripheral master for transfers on allocated channel

Example:

	serial@e0000000 {
		compatible = "arm,pl011", "arm,primecell";
		reg = <0xe0000000 0x1000>;
		interrupts = <0 35 0x4>;
		dmas = <&dmahost 12 0 1>,
			<&dmahost 13 1 0>;
		dma-names = "rx", "rx";
	};