70 lines
2.4 KiB
Plaintext
70 lines
2.4 KiB
Plaintext
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Texas Instruments DMA Crossbar (DMA request router)
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Required properties:
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- compatible: "ti,dra7-dma-crossbar" for DRA7xx DMA crossbar
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"ti,am335x-edma-crossbar" for AM335x and AM437x
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- reg: Memory map for accessing module
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- #dma-cells: Should be set to to match with the DMA controller's dma-cells
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for ti,dra7-dma-crossbar and <3> for ti,am335x-edma-crossbar.
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- dma-requests: Number of DMA requests the crossbar can receive
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- dma-masters: phandle pointing to the DMA controller
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The DMA controller node need to have the following poroperties:
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- dma-requests: Number of DMA requests the controller can handle
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Optional properties:
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- ti,dma-safe-map: Safe routing value for unused request lines
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- ti,reserved-dma-request-ranges: DMA request ranges which should not be used
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when mapping xbar input to DMA request, they are either
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allocated to be used by for example the DSP or they are used as
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memcpy channels in eDMA.
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Notes:
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When requesting channel via ti,dra7-dma-crossbar, the DMA clinet must request
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the DMA event number as crossbar ID (input to the DMA crossbar).
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For ti,am335x-edma-crossbar: the meaning of parameters of dmas for clients:
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dmas = <&edma_xbar 12 0 1>; where <12> is the DMA request number, <0> is the TC
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the event should be assigned and <1> is the mux selection for in the crossbar.
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When mux 0 is used the DMA channel can be requested directly from edma node.
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Example:
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/* DMA controller */
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sdma: dma-controller@4a056000 {
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compatible = "ti,omap4430-sdma";
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reg = <0x4a056000 0x1000>;
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interrupts = <GIC_SPI 7 IRQ_TYPE_LEVEL_HIGH>,
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<GIC_SPI 8 IRQ_TYPE_LEVEL_HIGH>,
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<GIC_SPI 9 IRQ_TYPE_LEVEL_HIGH>,
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<GIC_SPI 10 IRQ_TYPE_LEVEL_HIGH>;
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#dma-cells = <1>;
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dma-channels = <32>;
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dma-requests = <127>;
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};
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/* DMA crossbar */
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sdma_xbar: dma-router@4a002b78 {
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compatible = "ti,dra7-dma-crossbar";
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reg = <0x4a002b78 0xfc>;
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#dma-cells = <1>;
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dma-requests = <205>;
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ti,dma-safe-map = <0>;
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/* Protect the sDMA request ranges: 10-14 and 100-126 */
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ti,reserved-dma-request-ranges = <10 5>, <100 27>;
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dma-masters = <&sdma>;
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};
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/* DMA client */
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uart1: serial@4806a000 {
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compatible = "ti,omap4-uart";
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reg = <0x4806a000 0x100>;
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interrupts-extended = <&gic GIC_SPI 67 IRQ_TYPE_LEVEL_HIGH>;
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ti,hwmods = "uart1";
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clock-frequency = <48000000>;
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status = "disabled";
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/* Requesting crossbar input 49 and 50 */
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dmas = <&sdma_xbar 49>, <&sdma_xbar 50>;
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dma-names = "tx", "rx";
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};
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