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| -rw-r--r-- | Documentation/devicetree/bindings/dma/ti-dma-crossbar.txt | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/dma/ti-dma-crossbar.txt b/Documentation/devicetree/bindings/dma/ti-dma-crossbar.txt new file mode 100644 index 000000000..47e477cce --- /dev/null +++ b/Documentation/devicetree/bindings/dma/ti-dma-crossbar.txt @@ -0,0 +1,68 @@ +Texas Instruments DMA Crossbar (DMA request router) + +Required properties: +- compatible: "ti,dra7-dma-crossbar" for DRA7xx DMA crossbar + "ti,am335x-edma-crossbar" for AM335x and AM437x +- reg: Memory map for accessing module +- #dma-cells: Should be set to match with the DMA controller's dma-cells + for ti,dra7-dma-crossbar and <3> for ti,am335x-edma-crossbar. +- dma-requests: Number of DMA requests the crossbar can receive +- dma-masters: phandle pointing to the DMA controller + +The DMA controller node need to have the following poroperties: +- dma-requests: Number of DMA requests the controller can handle + +Optional properties: +- ti,dma-safe-map: Safe routing value for unused request lines +- ti,reserved-dma-request-ranges: DMA request ranges which should not be used + when mapping xbar input to DMA request, they are either + allocated to be used by for example the DSP or they are used as + memcpy channels in eDMA. + +Notes: +When requesting channel via ti,dra7-dma-crossbar, the DMA clinet must request +the DMA event number as crossbar ID (input to the DMA crossbar). + +For ti,am335x-edma-crossbar: the meaning of parameters of dmas for clients: +dmas = <&edma_xbar 12 0 1>; where <12> is the DMA request number, <0> is the TC +the event should be assigned and <1> is the mux selection for in the crossbar. +When mux 0 is used the DMA channel can be requested directly from edma node. + +Example: + +/* DMA controller */ +sdma: dma-controller@4a056000 { + compatible = "ti,omap4430-sdma"; + reg = <0x4a056000 0x1000>; + interrupts = <GIC_SPI 7 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 8 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 9 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 10 IRQ_TYPE_LEVEL_HIGH>; + #dma-cells = <1>; + dma-channels = <32>; + dma-requests = <127>; +}; + +/* DMA crossbar */ +sdma_xbar: dma-router@4a002b78 { + compatible = "ti,dra7-dma-crossbar"; + reg = <0x4a002b78 0xfc>; + #dma-cells = <1>; + dma-requests = <205>; + ti,dma-safe-map = <0>; + /* Protect the sDMA request ranges: 10-14 and 100-126 */ + ti,reserved-dma-request-ranges = <10 5>, <100 27>; + dma-masters = <&sdma>; +}; + +/* DMA client */ +uart1: serial@4806a000 { + compatible = "ti,omap4-uart"; + reg = <0x4806a000 0x100>; + interrupts-extended = <&gic GIC_SPI 67 IRQ_TYPE_LEVEL_HIGH>; + ti,hwmods = "uart1"; + clock-frequency = <48000000>; + /* Requesting crossbar input 49 and 50 */ + dmas = <&sdma_xbar 49>, <&sdma_xbar 50>; + dma-names = "tx", "rx"; +}; |