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* Freescale Direct Memory Access (DMA) Controller for i.MX
This document will only describe differences to the generic DMA Controller and
DMA request bindings as described in dma/dma.txt .
* DMA controller
Required properties:
- compatible : Should be "fsl,<chip>-dma". chip can be imx1, imx21 or imx27
- reg : Should contain DMA registers location and length
- interrupts : First item should be DMA interrupt, second one is optional and
should contain DMA Error interrupt
- #dma-cells : Has to be 1. imx-dma does not support anything else.
Optional properties:
- #dma-channels : Number of DMA channels supported. Should be 16.
- #dma-requests : Number of DMA requests supported.
Example:
dma: dma@10001000 {
compatible = "fsl,imx27-dma";
reg = <0x10001000 0x1000>;
interrupts = <32 33>;
#dma-cells = <1>;
#dma-channels = <16>;
};
* DMA client
Clients have to specify the DMA requests with phandles in a list.
Required properties:
- dmas: List of one or more DMA request specifiers. One DMA request specifier
consists of a phandle to the DMA controller followed by the integer
specifying the request line.
- dma-names: List of string identifiers for the DMA requests. For the correct
names, have a look at the specific client driver.
Example:
sdhci1: sdhci@10013000 {
...
dmas = <&dma 7>;
dma-names = "rx-tx";
...
};
* DMA capability limitation
Specify the DMA capability limitations.
For example, some SoCs only support up to 32bit DMA capability, although
they are 64bit SoCs.
- only-dma-mask32: 1 means that the SoCs only suppot up to 32bit DMA
capability.
Example:
dma_cap: dma_cap {
compatible = "dma-capability";
only-dma-mask32 = <1>;
};