remoteproc: dt: Provide bindings for ST's Remote Processor Controller driver

Signed-off-by: NLudovic Barre <ludovic.barre@st.com>
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NBjorn Andersson <bjorn.andersson@linaro.org>

Documentation/devicetree/bindings/remoteproc/st-rproc.txt

+STMicroelectronics Co-Processor Bindings
+----------------------------------------
+
+This binding provides support for adjunct processors found on ST SoCs.
+
+Co-processors can be controlled from the bootloader or the primary OS. If
+the bootloader starts a co-processor, the primary OS must detect its state
+and act accordingly.
+
+Required properties:
+- compatible		Should be one of:
+				"st,st231-rproc"
+				"st,st40-rproc"
+- memory-region		Reserved memory (See: ../reserved-memory/reserved-memory.txt)
+- resets		Reset lines (See: ../reset/reset.txt)
+- reset-names		Must be "sw_reset" and "pwr_reset"
+- clocks		Clock for co-processor (See: ../clock/clock-bindings.txt)
+- clock-frequency	Clock frequency to set co-processor at if the bootloader
+			hasn't already done so
+- st,syscfg		System configuration register which holds the boot vector
+			for the co-processor
+				1st cell: Phandle to syscon block
+				2nd cell: Boot vector register offset
+
+Example:
+
+	audio_reserved: rproc@42000000 {
+		compatible = "shared-dma-pool";
+		reg = <0x42000000 0x01000000>;
+		no-map;
+	};
+
+	st231-audio {
+		compatible	= "st,st231-rproc";
+		memory-region	= <&audio_reserved>;
+		resets		= <&softreset STIH407_ST231_AUD_SOFTRESET>;
+		reset-names	= "sw_reset";
+		clocks		= <&clk_s_c0_flexgen CLK_ST231_AUD_0>;
+		clock-frequency	= <600000000>;
+		st,syscfg	= <&syscfg_core 0x228>;
+	};