69 lines
2.3 KiB
Plaintext
69 lines
2.3 KiB
Plaintext
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 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";
|
|
};
|