dt-bindings: remoteproc: Add Keystone DSP remoteproc binding

Add the device tree bindings document for the Texas Instrument's
Keystone 2 DSP remoteproc devices.
Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Sam Nelson <sam.nelson@ti.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Documentation/devicetree/bindings/remoteproc/ti,keystone-rproc.txt

+TI Keystone DSP devices
+=======================
+
+The TI Keystone 2 family of SoCs usually have one or more (upto 8) TI DSP Core
+sub-systems that are used to offload some of the processor-intensive tasks or
+algorithms, for achieving various system level goals.
+
+These processor sub-systems usually contain additional sub-modules like L1
+and/or L2 caches/SRAMs, an Interrupt Controller, an external memory controller,
+a dedicated local power/sleep controller etc. The DSP processor core in
+Keystone 2 SoCs is usually a TMS320C66x CorePac processor.
+
+DSP Device Node:
+================
+Each DSP Core sub-system is represented as a single DT node, and should also
+have an alias with the stem 'rproc' defined. Each node has a number of required
+or optional properties that enable the OS running on the host processor (ARM
+CorePac) to perform the device management of the remote processor and to
+communicate with the remote processor.
+
+Required properties:
+--------------------
+The following are the mandatory properties:
+
+- compatible:		Should be one of the following,
+			    "ti,k2hk-dsp" for DSPs on Keystone 2 66AK2H/K SoCs
+			    "ti,k2l-dsp" for DSPs on Keystone 2 66AK2L SoCs
+			    "ti,k2e-dsp" for DSPs on Keystone 2 66AK2E SoCs
+
+- reg:			Should contain an entry for each value in 'reg-names'.
+			Each entry should have the memory region's start address
+			and the size of the region, the representation matching
+			the parent node's '#address-cells' and '#size-cells' values.
+
+- reg-names:		Should contain strings with the following names, each
+			representing a specific internal memory region, and
+			should be defined in this order,
+			     "l2sram", "l1pram", "l1dram"
+
+- clocks: 		Should contain the device's input clock, and should be
+			defined as per the bindings in,
+			Documentation/devicetree/bindings/clock/keystone-gate.txt
+
+- ti,syscon-dev:	Should be a pair of the phandle to the Keystone Device
+			State Control node, and the register offset of the DSP
+			boot address register within that node's address space.
+
+- resets:		Should contain the phandle to the reset controller node
+			managing the resets for this device, and a reset
+			specifier. Please refer to the following reset bindings
+			for the reset argument specifier as per SoC,
+			Documentation/devicetree/bindings/reset/ti-syscon-reset.txt
+			    for 66AK2HK/66AK2L/66AK2E SoCs
+
+- interrupt-parent:	Should contain a phandle to the Keystone 2 IRQ controller
+			IP node that is used by the ARM CorePac processor to
+			receive interrupts from the DSP remote processors. See
+			Documentation/devicetree/bindings/interrupt-controller/ti,keystone-irq.txt
+			for details.
+
+- interrupts: 		Should contain an entry for each value in 'interrupt-names'.
+			Each entry should have the interrupt source number used by
+			the remote processor to the host processor. The values should
+			follow the interrupt-specifier format as dictated by the
+			'interrupt-parent' node. The purpose of each is as per the
+			description in the 'interrupt-names' property.
+
+- interrupt-names:	Should contain strings with the following names, each
+			representing a specific interrupt,
+			    "vring" - interrupt for virtio based IPC
+			    "exception" - interrupt for exception notification
+
+- kick-gpios: 		Should specify the gpio device needed for the virtio IPC
+			stack. This will be used to interrupt the remote processor.
+			The gpio device to be used is as per the bindings in,
+			Documentation/devicetree/bindings/gpio/gpio-dsp-keystone.txt
+
+Optional properties:
+--------------------
+
+- memory-region:	phandle to the reserved memory node to be associated
+			with the remoteproc device. The reserved memory node
+			can be a CMA memory node, and should be defined as
+			per the bindings in
+			Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
+
+
+Example:
+--------
+	/* 66AK2H/K DSP aliases */
+	aliases {
+		rproc0 = &dsp0;
+		rproc1 = &dsp1;
+		rproc2 = &dsp2;
+		rproc3 = &dsp3;
+		rproc4 = &dsp4;
+		rproc5 = &dsp5;
+		rproc6 = &dsp6;
+		rproc7 = &dsp7;
+	};
+
+	/* 66AK2H/K DSP memory node */
+	reserved-memory {
+		#address-cells = <2>;
+		#size-cells = <2>;
+		ranges;
+
+		dsp_common_memory: dsp-common-memory@81f800000 {
+			compatible = "shared-dma-pool";
+			reg = <0x00000008 0x1f800000 0x00000000 0x800000>;
+			reusable;
+		};
+	};
+
+	/* 66AK2H/K DSP node */
+	soc {
+		dsp0: dsp@10800000 {
+			compatible = "ti,k2hk-dsp";
+			reg = <0x10800000 0x00100000>,
+			      <0x10e00000 0x00008000>,
+			      <0x10f00000 0x00008000>;
+			reg-names = "l2sram", "l1pram", "l1dram";
+			clocks = <&clkgem0>;
+			ti,syscon-dev = <&devctrl 0x40>;
+			resets = <&pscrst 0>;
+			interrupt-parent = <&kirq0>;
+			interrupts = <0 8>;
+			interrupt-names = "vring", "exception";
+			kick-gpios = <&dspgpio0 27 0>;
+			memory-region = <&dsp_common_memory>;
+		};
+
+	};