dt-bindings: remoteproc: Add Keystone DSP remoteproc binding

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>;

		};

	};