dt-bindings: remoteproc: Add bindings for R5F subsystem on TI K3 SoCs

The Texas Instruments K3 family of SoCs have one of more dual-core
Arm Cortex R5F processor subsystems/clusters (R5FSS). Add the device
tree bindings document for these R5F subsystem devices. These R5F
processors do not have an MMU, and so require fixed memory carveout
regions matching the firmware image addresses. The nodes require more
than one memory region, with the first memory region used for DMA
allocations at runtime. The remaining memory regions are reserved
and are used for the loading and running of the R5F remote processors.

The added example illustrates the DT nodes for the single R5FSS device
present on K3 AM65x family of SoCs.

Signed-off-by: Suman Anna <s-anna@ti.com>

Documentation/devicetree/bindings/remoteproc/ti,k3-r5f-rproc.txt

@@ -0,0 +1,215 @@
+TI K3 R5F processor subsystems
+==============================
+
+The TI K3 family of SoCs usually have one or more dual-core Arm Cortex
+R5F processor subsystems/clusters (R5FSS). The dual core cluster can be
+used either in a LockStep mode providing safety/fault tolerance features
+or in a Split mode providing two individual compute cores for doubling
+the compute capacity. These are used together with other processors
+present on the SoC to achieve various system level goals.
+
+R5F Sub-System Device Node:
+===========================
+Each Dual-Core R5F sub-system is represented as a single DTS node representing
+the cluster, with a pair of child DT nodes representing the individual R5F
+cores. Each node has a number of required or optional properties that enable
+the OS running on the host processor 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,am654-r5fss" for R5F clusters/subsystems on
+			                       K3 AM65x SoCs
+- power-domains:	Should contain a phandle to a PM domain provider node
+			and an args specifier containing the R5FSS device id
+			value. This property is as per the binding,
+			Documentation/devicetree/bindings/soc/ti/sci-pm-domain.txt
+- #address-cells:	Should be 1
+- #size-cells:		Should be 1
+- ranges:		Standard ranges definition providing translations for
+			R5F TCM address spaces
+
+Optional properties:
+--------------------
+- lockstep-mode:	Configuration Mode for the Dual R5F cores within the R5F
+			cluster. Should be either a value of 1 (LockStep mode) or
+			0 (Split mode), default is LockStep mode if omitted.
+
+
+R5F Processor Child Nodes:
+==========================
+The R5F Sub-System device node should define two R5F child nodes, each node
+representing a TI instantiation of the Arm Cortex R5F core. There are some
+specific integration differences for the IP like the usage of a Region Address
+Translator (RAT) for translating the larger SoC bus addresses into a 32-bit
+address space for the processor.
+
+Required properties:
+--------------------
+The following are the mandatory properties:
+
+- compatible:		Should be one of the following,
+			    "ti,am654-r5f" for the R5F cores in K3 AM65x 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,
+			     "atcm", "btcm"
+- ti,sci:		Should be a phandle to the TI-SCI System Controller node
+- ti,sci-dev-id:	Should contain the TI-SCI device id corresponding to the
+			R5F Core. Please refer to the corresponding System
+			Controller documentation for valid values for the R5F
+			cores.
+- ti,sci-proc-ids:	Should contain 2 integer values. The first cell should
+			contain the TI-SCI processor id for the R5F core device
+			and the second cell should contain the TI-SCI host id to
+			which the processor control ownership should be
+			transferred to.
+- 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,
+			Documentation/devicetree/bindings/reset/ti,sci-reset.txt
+			    for AM65x SoCs
+
+The following properties are mandatory for R5F Core0 in both LockStep and Split
+modes, and are mandatory for R5F Core1 _only_ in Split mode. They are unused for
+R5F Core1 in LockStep mode:
+
+- mboxes:		OMAP Mailbox specifier denoting the sub-mailbox, to be
+			used for communication with the remote processor. The
+			specifier format is as per the bindings,
+			Documentation/devicetree/bindings/mailbox/omap-mailbox.txt
+			This property should match with the sub-mailbox node
+			used in the firmware image.
+- memory-region:	phandle to the reserved memory nodes to be associated
+			with the remoteproc device. There should be atleast two
+			reserved memory nodes defined - the first one would be
+			used for dynamic DMA allocations like vrings and vring
+			buffers, and the remaining ones used for the firmware
+			image sections. The reserved memory nodes should be
+			carveout nodes, and should be defined as per the
+			bindings in
+			Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
+
+Optional properties:
+--------------------
+The following properties are optional properties for each of the R5F cores:
+
+- atcm-enable:		R5F core configuration mode dictating if ATCM should be
+			enabled. Should be either a value of 1 (enabled) or
+			0 (disabled), default is disabled if omitted. R5F view
+			of ATCM dictated by loczrama property.
+- btcm-enable:		R5F core configuration mode dictating if BTCM should be
+			enabled. Should be either a value of 1 (enabled) or
+			0 (disabled), default is enabled if omitted. R5F view
+			of BTCM dictated by loczrama property.
+- loczrama:		R5F core configuration mode dictating which TCM should
+			appear at address 0 (from core's view). Should be either
+			a value of 1 (ATCM at 0x0) or 0 (BTCM at 0x0), default
+			value is 1 if omitted.
+
+
+Example:
+--------
+1. AM654 SoC
+	/* AM65x remoteproc alias */
+	aliases {
+		rproc0 = &mcu_r5fss0_core0;
+	};
+
+	/* R5F DDR Carveout reserved memory nodes */
+	reserved-memory {
+		#address-cells = <2>;
+		#size-cells = <2>;
+		ranges;
+
+		mcu_r5fss0_core1_dma_memory_region: r5f-dma-memory@9b000000 {
+			compatible = "shared-dma-pool";
+			reg = <0x00 0x9b000000 0x00 0x100000>;
+			no-map;
+		};
+
+		mcu_r5fss0_core1_memory_region: r5f-memory@9b100000 {
+			compatible = "shared-dma-pool";
+			reg = <0x00 0x9b100000 0x00 0xf00000>;
+			no-map;
+		};
+
+		mcu_r5fss0_core0_dma_memory_region: r5f-dma-memory@9c000000 {
+			compatible = "shared-dma-pool";
+			reg = <0x00 0x9c000000 0x00 0x100000>;
+			no-map;
+		};
+
+		mcu_r5fss0_core0_memory_region: r5f-memory@9c100000 {
+			compatible = "shared-dma-pool";
+			reg = <0x00 0x9c100000 0x00 0x700000>;
+			no-map;
+		};
+	};
+
+	cbass_main: interconnect@100000 {
+		compatible = "simple-bus";
+		#address-cells = <2>;
+		#size-cells = <2>;
+		ranges = <0x00 0x41000000 0x00 0x41000000 0x00 0x00020000>,
+			 <0x00 0x41400000 0x00 0x41400000 0x00 0x00020000>;
+
+		cbass_mcu: interconnect@28380000 {
+			compatible = "simple-bus";
+			#address-cells = <2>;
+			#size-cells = <2>;
+			ranges = <0x00 0x41000000 0x00 0x41000000 0x00 0x00020000>, /* MCU R5F Core0 */
+				 <0x00 0x41400000 0x00 0x41400000 0x00 0x00020000>; /* MCU R5F Core1 */
+
+			/* AM65x MCU R5FSS node */
+			mcu_r5fss0: r5fss@41000000 {
+				compatible = "ti,am654-r5fss";
+				power-domains = <&k3_pds 129>;
+				lockstep-mode = <1>;
+				#address-cells = <1>;
+				#size-cells = <1>;
+				ranges = <0x41000000 0x00 0x41000000 0x20000>,
+					 <0x41400000 0x00 0x41400000 0x20000>;
+
+				mcu_r5f0: r5f@41000000 {
+					compatible = "ti,am654-r5f";
+					reg = <0x41000000 0x00008000>,
+					      <0x41010000 0x00008000>;
+					reg-names = "atcm", "btcm";
+					ti,sci = <&dmsc>;
+					ti,sci-dev-id = <159>;
+					ti,sci-proc-ids = <0x01 0xFF>;
+					resets = <&k3_reset 159 1>;
+					atcm-enable = <1>;
+					btcm-enable = <1>;
+					loczrama = <1>;
+					mboxes = <&mailbox0 &mbox_mcu_r5fss0_core0>;
+					memory-region = <&mcu_r5fss0_core0_dma_memory_region>,
+							<&mcu_r5fss0_core0_memory_region>;
+				};
+
+				mcu_r5f1: r5f@41400000 {
+					compatible = "ti,am654-r5f";
+					reg = <0x41400000 0x00008000>,
+					      <0x41410000 0x00008000>;
+					reg-names = "atcm", "btcm";
+					ti,sci = <&dmsc>;
+					ti,sci-dev-id = <245>;
+					ti,sci-proc-ids = <0x02 0xFF>;
+					resets = <&k3_reset 245 1>;
+					atcm-enable = <1>;
+					btcm-enable = <1>;
+					loczrama = <1>;
+					mboxes = <&mailbox1 &mbox_mcu_r5fss0_core1>;
+				};
+			};
+		};
+	};