summaryrefslogtreecommitdiffstats
path: root/Documentation/devicetree/bindings/dma/ti-dma-crossbar.txt
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/devicetree/bindings/dma/ti-dma-crossbar.txt')
-rw-r--r--Documentation/devicetree/bindings/dma/ti-dma-crossbar.txt68
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..b849a1ed3
--- /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 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";
+};