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dma: Add Xilinx Video DMA DT Binding Documentation
Device-tree binding documentation of Xilinx Video DMA Engine
Signed-off-by: Srikanth Thokala <sthokal@xilinx.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
authored by
Srikanth Thokala
and committed by
Vinod Koul
eebeac03
a798c10f
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Documentation/devicetree/bindings/dma/xilinx/xilinx_vdma.txt
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Documentation/devicetree/bindings/dma/xilinx/xilinx_vdma.txt
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Xilinx AXI VDMA engine, it does transfers between memory and video devices.
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It can be configured to have one channel or two channels. If configured
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as two channels, one is to transmit to the video device and another is
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to receive from the video device.
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Required properties:
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- compatible: Should be "xlnx,axi-vdma-1.00.a"
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- #dma-cells: Should be <1>, see "dmas" property below
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- reg: Should contain VDMA registers location and length.
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- xlnx,num-fstores: Should be the number of framebuffers as configured in h/w.
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- dma-channel child node: Should have at least one channel and can have up to
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two channels per device. This node specifies the properties of each
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DMA channel (see child node properties below).
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Optional properties:
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- xlnx,include-sg: Tells configured for Scatter-mode in
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the hardware.
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- xlnx,flush-fsync: Tells which channel to Flush on Frame sync.
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It takes following values:
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{1}, flush both channels
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{2}, flush mm2s channel
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{3}, flush s2mm channel
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Required child node properties:
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- compatible: It should be either "xlnx,axi-vdma-mm2s-channel" or
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"xlnx,axi-vdma-s2mm-channel".
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- interrupts: Should contain per channel VDMA interrupts.
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- xlnx,data-width: Should contain the stream data width, take values
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{32,64...1024}.
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Optional child node properties:
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- xlnx,include-dre: Tells hardware is configured for Data
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Realignment Engine.
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- xlnx,genlock-mode: Tells Genlock synchronization is
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enabled/disabled in hardware.
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Example:
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++++++++
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axi_vdma_0: axivdma@40030000 {
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compatible = "xlnx,axi-vdma-1.00.a";
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#dma_cells = <1>;
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reg = < 0x40030000 0x10000 >;
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xlnx,num-fstores = <0x8>;
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xlnx,flush-fsync = <0x1>;
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dma-channel@40030000 {
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compatible = "xlnx,axi-vdma-mm2s-channel";
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interrupts = < 0 54 4 >;
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xlnx,datawidth = <0x40>;
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} ;
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dma-channel@40030030 {
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compatible = "xlnx,axi-vdma-s2mm-channel";
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interrupts = < 0 53 4 >;
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xlnx,datawidth = <0x40>;
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} ;
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} ;
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* DMA client
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Required properties:
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- dmas: a list of <[Video DMA device phandle] [Channel ID]> pairs,
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where Channel ID is '0' for write/tx and '1' for read/rx
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channel.
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- dma-names: a list of DMA channel names, one per "dmas" entry
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Example:
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++++++++
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vdmatest_0: vdmatest@0 {
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compatible ="xlnx,axi-vdma-test-1.00.a";
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dmas = <&axi_vdma_0 0
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&axi_vdma_0 1>;
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dma-names = "vdma0", "vdma1";
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} ;