Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 109 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/dma/dma.txt b/Documentation/devicetree/bindings/dma/dma.txt
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+* Generic DMA Controller and DMA request bindings
+
+Generic binding to provide a way for a driver using DMA Engine to retrieve the
+DMA request or channel information that goes from a hardware device to a DMA
+controller.
+
+
+* DMA controller
+
+Required property:
+- #dma-cells: 		Must be at least 1. Used to provide DMA controller
+			specific information. See DMA client binding below for
+			more details.
+
+Optional properties:
+- dma-channels: 	Number of DMA channels supported by the controller.
+- dma-requests: 	Number of DMA request signals supported by the
+			controller.
+
+Example:
+
+	dma: dma@48000000 {
+		compatible = "ti,omap-sdma";
+		reg = <0x48000000 0x1000>;
+		interrupts = <0 12 0x4
+			      0 13 0x4
+			      0 14 0x4
+			      0 15 0x4>;
+		#dma-cells = <1>;
+		dma-channels = <32>;
+		dma-requests = <127>;
+	};
+
+* DMA router
+
+DMA routers are transparent IP blocks used to route DMA request lines from
+devices to the DMA controller. Some SoCs (like TI DRA7x) have more peripherals
+integrated with DMA requests than what the DMA controller can handle directly.
+
+Required property:
+- dma-masters:		phandle of the DMA controller or list of phandles for
+			the DMA controllers the router can direct the signal to.
+- #dma-cells: 		Must be at least 1. Used to provide DMA router specific
+			information. See DMA client binding below for more
+			details.
+
+Optional properties:
+- dma-requests: 	Number of incoming request lines the router can handle.
+- In the node pointed by the dma-masters:
+	- dma-requests:	The router driver might need to look for this in order
+			to configure the routing.
+
+Example:
+	sdma_xbar: dma-router@4a002b78 {
+		compatible = "ti,dra7-dma-crossbar";
+		reg = <0x4a002b78 0xfc>;
+		#dma-cells = <1>;
+		dma-requests = <205>;
+		ti,dma-safe-map = <0>;
+		dma-masters = <&sdma>;
+	};
+
+* DMA client
+
+Client drivers should specify the DMA property using a phandle to the controller
+followed by DMA controller specific data.
+
+Required property:
+- dmas:			List of one or more DMA specifiers, each consisting of
+			- A phandle pointing to DMA controller node
+			- A number of integer cells, as determined by the
+			  #dma-cells property in the node referenced by phandle
+			  containing DMA controller specific information. This
+			  typically contains a DMA request line number or a
+			  channel number, but can contain any data that is
+			  required for configuring a channel.
+- dma-names: 		Contains one identifier string for each DMA specifier in
+			the dmas property. The specific strings that can be used
+			are defined in the binding of the DMA client device.
+			Multiple DMA specifiers can be used to represent
+			alternatives and in this case the dma-names for those
+			DMA specifiers must be identical (see examples).
+
+Examples:
+
+1. A device with one DMA read channel, one DMA write channel:
+
+	i2c1: i2c@1 {
+		...
+		dmas = <&dma 2		/* read channel */
+			&dma 3>;	/* write channel */
+		dma-names = "rx", "tx";
+		...
+	};
+
+2. A single read-write channel with three alternative DMA controllers:
+
+	dmas = <&dma1 5
+		&dma2 7
+		&dma3 2>;
+	dma-names = "rx-tx", "rx-tx", "rx-tx";
+
+3. A device with three channels, one of which has two alternatives:
+
+	dmas = <&dma1 2			/* read channel */
+		&dma1 3			/* write channel */
+		&dma2 0			/* error read */
+		&dma3 0>;		/* alternative error read */
+	dma-names = "rx", "tx", "error", "error";