Xilinx AXI CDMA engine, it does transfers between memory-mapped source
address and a memory-mapped destination address.

Required properties:
- compatible		: Should be "xlnx,axi-cdma-1.00.a"
- #dma-cells		: Should be <1>, see "dmas" property below
- reg			: Should contain cdma registers location and length.
- dma-channel child node: Should have only one channel

Optional properties:
- xlnx,include-sg	: Tells whether configured for Scatter-mode in
			  the hardware.

Required child node properties:
- interrupts		: Should contain per channel CDMA interrupts.
- xlnx,datawidth	: Should contain the stream data width, take values
			  {32,64...1024}.

Option child node properties:
- xlnx,has-dre		: Tells whether hardware is configured for Data
			  Realignment Engine.

Example:
++++++++

axi_cdma_0: axicdma@7e200000 {
       compatible = "xlnx,axi-cdma-1.00.a";
       #dma-cells = <1>;
       reg = < 0x7e200000 0x10000 >;
       dma-channel@7e200000 {
               compatible = "xlnx,axi-cdma-channel";
               interrupts = < 0 55 4 >;
               xlnx,datawidth = <0x40>;
       } ;
} ;


* DMA client

Required properties:
- dmas		: a list of <[Central DMA device phandle] [Channel ID]> pairs,
		  where Channel ID is '0' for write/tx and '1' for read/rx
                  channel.
- dma-names	: a list of DMA channel names, one per "dmas" entry

Example:
++++++++

cdmatest_0: cdmatest@0 {
       compatible ="xlnx,axi-cdma-test-1.00.a";
       dmas = <&axi_cdma_0 0>;
       dma-names = "cdma";
} ;
