1 This file has been moved to dma-controller.yam !! 1 * Generic DMA Controller and DMA request bindings
>> 2
>> 3 Generic binding to provide a way for a driver using DMA Engine to retrieve the
>> 4 DMA request or channel information that goes from a hardware device to a DMA
>> 5 controller.
>> 6
>> 7
>> 8 * DMA controller
>> 9
>> 10 Required property:
>> 11 - #dma-cells: Must be at least 1. Used to provide DMA controller
>> 12 specific information. See DMA client binding below for
>> 13 more details.
>> 14
>> 15 Optional properties:
>> 16 - dma-channels: Number of DMA channels supported by the controller.
>> 17 - dma-requests: Number of DMA request signals supported by the
>> 18 controller.
>> 19
>> 20 Example:
>> 21
>> 22 dma: dma@48000000 {
>> 23 compatible = "ti,omap-sdma";
>> 24 reg = <0x48000000 0x1000>;
>> 25 interrupts = <0 12 0x4
>> 26 0 13 0x4
>> 27 0 14 0x4
>> 28 0 15 0x4>;
>> 29 #dma-cells = <1>;
>> 30 dma-channels = <32>;
>> 31 dma-requests = <127>;
>> 32 };
>> 33
>> 34 * DMA router
>> 35
>> 36 DMA routers are transparent IP blocks used to route DMA request lines from
>> 37 devices to the DMA controller. Some SoCs (like TI DRA7x) have more peripherals
>> 38 integrated with DMA requests than what the DMA controller can handle directly.
>> 39
>> 40 Required property:
>> 41 - dma-masters: phandle of the DMA controller or list of phandles for
>> 42 the DMA controllers the router can direct the signal to.
>> 43 - #dma-cells: Must be at least 1. Used to provide DMA router specific
>> 44 information. See DMA client binding below for more
>> 45 details.
>> 46
>> 47 Optional properties:
>> 48 - dma-requests: Number of incoming request lines the router can handle.
>> 49 - In the node pointed by the dma-masters:
>> 50 - dma-requests: The router driver might need to look for this in order
>> 51 to configure the routing.
>> 52
>> 53 Example:
>> 54 sdma_xbar: dma-router@4a002b78 {
>> 55 compatible = "ti,dra7-dma-crossbar";
>> 56 reg = <0x4a002b78 0xfc>;
>> 57 #dma-cells = <1>;
>> 58 dma-requests = <205>;
>> 59 ti,dma-safe-map = <0>;
>> 60 dma-masters = <&sdma>;
>> 61 };
>> 62
>> 63 * DMA client
>> 64
>> 65 Client drivers should specify the DMA property using a phandle to the controller
>> 66 followed by DMA controller specific data.
>> 67
>> 68 Required property:
>> 69 - dmas: List of one or more DMA specifiers, each consisting of
>> 70 - A phandle pointing to DMA controller node
>> 71 - A number of integer cells, as determined by the
>> 72 #dma-cells property in the node referenced by phandle
>> 73 containing DMA controller specific information. This
>> 74 typically contains a DMA request line number or a
>> 75 channel number, but can contain any data that is
>> 76 required for configuring a channel.
>> 77 - dma-names: Contains one identifier string for each DMA specifier in
>> 78 the dmas property. The specific strings that can be used
>> 79 are defined in the binding of the DMA client device.
>> 80 Multiple DMA specifiers can be used to represent
>> 81 alternatives and in this case the dma-names for those
>> 82 DMA specifiers must be identical (see examples).
>> 83
>> 84 Examples:
>> 85
>> 86 1. A device with one DMA read channel, one DMA write channel:
>> 87
>> 88 i2c1: i2c@1 {
>> 89 ...
>> 90 dmas = <&dma 2 /* read channel */
>> 91 &dma 3>; /* write channel */
>> 92 dma-names = "rx", "tx";
>> 93 ...
>> 94 };
>> 95
>> 96 2. A single read-write channel with three alternative DMA controllers:
>> 97
>> 98 dmas = <&dma1 5
>> 99 &dma2 7
>> 100 &dma3 2>;
>> 101 dma-names = "rx-tx", "rx-tx", "rx-tx";
>> 102
>> 103 3. A device with three channels, one of which has two alternatives:
>> 104
>> 105 dmas = <&dma1 2 /* read channel */
>> 106 &dma1 3 /* write channel */
>> 107 &dma2 0 /* error read */
>> 108 &dma3 0>; /* alternative error read */
>> 109 dma-names = "rx", "tx", "error", "error";
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.