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>

diff --git a/Documentation/devicetree/bindings/remoteproc/ti,keystone-rproc.txt b/Documentation/devicetree/bindings/remoteproc/ti,keystone-rproc.txt
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+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>;
+               };
+
+       };