fsl-edma.txt

* Freescale enhanced Direct Memory Access(eDMA) Controller

  The eDMA channels have multiplex capability by programmble memory-mapped
registers. channels are split into two groups, called DMAMUX0 and DMAMUX1,
specific DMA request source can only be multiplexed by any channel of certain
group, DMAMUX0 or DMAMUX1, but not both.

* eDMA Controller
Required properties:
- compatible :
	- "fsl,vf610-edma" for eDMA used similar to that on Vybrid vf610 SoC
	- "fsl,imx7ulp-edma" for eDMA2 used similar to that on i.mx7ulp
	- "fsl,ls1028a-edma" followed by "fsl,vf610-edma" for eDMA used on the
	  LS1028A SoC.
- reg : Specifies base physical address(s) and size of the eDMA registers.
	The 1st region is eDMA control register's address and size.
	The 2nd and the 3rd regions are programmable channel multiplexing
	control register's address and size.
- interrupts : A list of interrupt-specifiers, one for each entry in
	interrupt-names on vf610 similar SoC. But for i.mx7ulp per channel
	per transmission interrupt, total 16 channel interrupt and 1
	error interrupt(located in the last), no interrupt-names list on
	i.mx7ulp for clean on dts.
- #dma-cells : Must be <2>.
	The 1st cell specifies the DMAMUX(0 for DMAMUX0 and 1 for DMAMUX1).
	Specific request source can only be multiplexed by specific channels
	group called DMAMUX.
	The 2nd cell specifies the request source(slot) ID.
	See the SoC's reference manual for all the supported request sources.
- dma-channels : Number of channels supported by the controller
- clock-names : A list of channel group clock names. Should contain:
	"dmamux0" - clock name of mux0 group
	"dmamux1" - clock name of mux1 group
	Note: No dmamux0 on i.mx7ulp, but another 'dma' clk added on i.mx7ulp.
- clocks : A list of phandle and clock-specifier pairs, one for each entry in
	clock-names.

Optional properties:
- big-endian: If present registers and hardware scatter/gather descriptors
	of the eDMA are implemented in big endian mode, otherwise in little
	mode.
- interrupt-names : Should contain the below on vf610 similar SoC but not used
	on i.mx7ulp similar SoC:
	"edma-tx" - the transmission interrupt
	"edma-err" - the error interrupt


Examples:

edma0: dma-controller@40018000 {
	#dma-cells = <2>;
	compatible = "fsl,vf610-edma";
	reg = <0x40018000 0x2000>,
		<0x40024000 0x1000>,
		<0x40025000 0x1000>;
	interrupts = <0 8 IRQ_TYPE_LEVEL_HIGH>,
		<0 9 IRQ_TYPE_LEVEL_HIGH>;
	interrupt-names = "edma-tx", "edma-err";
	dma-channels = <32>;
	clock-names = "dmamux0", "dmamux1";
	clocks = <&clks VF610_CLK_DMAMUX0>,
		<&clks VF610_CLK_DMAMUX1>;
}; /* vf610 */

edma1: dma-controller@40080000 {
	#dma-cells = <2>;
	compatible = "fsl,imx7ulp-edma";
	reg = <0x40080000 0x2000>,
		<0x40210000 0x1000>;
	dma-channels = <32>;
	interrupts = <GIC_SPI 0 IRQ_TYPE_LEVEL_HIGH>,
		     <GIC_SPI 1 IRQ_TYPE_LEVEL_HIGH>,
		     <GIC_SPI 2 IRQ_TYPE_LEVEL_HIGH>,
		     <GIC_SPI 3 IRQ_TYPE_LEVEL_HIGH>,
		     <GIC_SPI 4 IRQ_TYPE_LEVEL_HIGH>,
		     <GIC_SPI 5 IRQ_TYPE_LEVEL_HIGH>,
		     <GIC_SPI 6 IRQ_TYPE_LEVEL_HIGH>,
		     <GIC_SPI 7 IRQ_TYPE_LEVEL_HIGH>,
		     <GIC_SPI 8 IRQ_TYPE_LEVEL_HIGH>,
		     <GIC_SPI 9 IRQ_TYPE_LEVEL_HIGH>,
		     <GIC_SPI 10 IRQ_TYPE_LEVEL_HIGH>,
		     <GIC_SPI 11 IRQ_TYPE_LEVEL_HIGH>,
		     <GIC_SPI 12 IRQ_TYPE_LEVEL_HIGH>,
		     <GIC_SPI 13 IRQ_TYPE_LEVEL_HIGH>,
		     <GIC_SPI 14 IRQ_TYPE_LEVEL_HIGH>,
		     <GIC_SPI 15 IRQ_TYPE_LEVEL_HIGH>,
		     /* last is eDMA2-ERR interrupt */
		     <GIC_SPI 16 IRQ_TYPE_LEVEL_HIGH>;
	clock-names = "dma", "dmamux0";
	clocks = <&pcc2 IMX7ULP_CLK_DMA1>,
		 <&pcc2 IMX7ULP_CLK_DMA_MUX1>;
}; /* i.mx7ulp */

* DMA clients
DMA client drivers that uses the DMA function must use the format described
in the dma.txt file, using a two-cell specifier for each channel: the 1st
specifies the channel group(DMAMUX) in which this request can be multiplexed,
and the 2nd specifies the request source.

Examples:

sai2: sai@40031000 {
	compatible = "fsl,vf610-sai";
	reg = <0x40031000 0x1000>;
	interrupts = <0 86 IRQ_TYPE_LEVEL_HIGH>;
	clock-names = "sai";
	clocks = <&clks VF610_CLK_SAI2>;
	dma-names = "tx", "rx";
	dmas = <&edma0 0 21>,
		<&edma0 0 20>;
};