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77 lines
2.6 KiB
Plaintext
77 lines
2.6 KiB
Plaintext
* Freescale enhanced Direct Memory Access(eDMA) Controller
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The eDMA channels have multiplex capability by programmble memory-mapped
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registers. channels are split into two groups, called DMAMUX0 and DMAMUX1,
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specific DMA request source can only be multiplexed by any channel of certain
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group, DMAMUX0 or DMAMUX1, but not both.
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* eDMA Controller
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Required properties:
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- compatible :
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- "fsl,vf610-edma" for eDMA used similar to that on Vybrid vf610 SoC
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- reg : Specifies base physical address(s) and size of the eDMA registers.
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The 1st region is eDMA control register's address and size.
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The 2nd and the 3rd regions are programmable channel multiplexing
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control register's address and size.
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- interrupts : A list of interrupt-specifiers, one for each entry in
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interrupt-names.
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- interrupt-names : Should contain:
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"edma-tx" - the transmission interrupt
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"edma-err" - the error interrupt
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- #dma-cells : Must be <2>.
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The 1st cell specifies the DMAMUX(0 for DMAMUX0 and 1 for DMAMUX1).
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Specific request source can only be multiplexed by specific channels
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group called DMAMUX.
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The 2nd cell specifies the request source(slot) ID.
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See the SoC's reference manual for all the supported request sources.
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- dma-channels : Number of channels supported by the controller
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- clock-names : A list of channel group clock names. Should contain:
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"dmamux0" - clock name of mux0 group
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"dmamux1" - clock name of mux1 group
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- clocks : A list of phandle and clock-specifier pairs, one for each entry in
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clock-names.
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Optional properties:
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- big-endian: If present registers and hardware scatter/gather descriptors
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of the eDMA are implemented in big endian mode, otherwise in little
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mode.
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Examples:
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edma0: dma-controller@40018000 {
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#dma-cells = <2>;
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compatible = "fsl,vf610-edma";
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reg = <0x40018000 0x2000>,
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<0x40024000 0x1000>,
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<0x40025000 0x1000>;
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interrupts = <0 8 IRQ_TYPE_LEVEL_HIGH>,
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<0 9 IRQ_TYPE_LEVEL_HIGH>;
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interrupt-names = "edma-tx", "edma-err";
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dma-channels = <32>;
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clock-names = "dmamux0", "dmamux1";
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clocks = <&clks VF610_CLK_DMAMUX0>,
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<&clks VF610_CLK_DMAMUX1>;
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};
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* DMA clients
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DMA client drivers that uses the DMA function must use the format described
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in the dma.txt file, using a two-cell specifier for each channel: the 1st
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specifies the channel group(DMAMUX) in which this request can be multiplexed,
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and the 2nd specifies the request source.
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Examples:
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sai2: sai@40031000 {
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compatible = "fsl,vf610-sai";
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reg = <0x40031000 0x1000>;
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interrupts = <0 86 IRQ_TYPE_LEVEL_HIGH>;
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clock-names = "sai";
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clocks = <&clks VF610_CLK_SAI2>;
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dma-names = "tx", "rx";
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dmas = <&edma0 0 21>,
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<&edma0 0 20>;
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status = "disabled";
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};
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