| * 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 |
| - "nxp,imx7ulp-edma" for eDMA used similar to that on NXP i.MX7ULP 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. |
| - interrupt-names : Should contain: |
| "edma-tx" - the transmission interrupt |
| "edma-err" - the error interrupt |
| - #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 |
| - 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. |
| |
| |
| 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>; |
| }; |
| |
| |
| * 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>; |
| }; |