* 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 = , , , , , , , , , , , , , , , , /* last is eDMA2-ERR interrupt */ ; 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>; };