[RFC PATCH 3/3] arm64: dts: ti: k3-am62x: Add overlay to use DSS in display sharing mode

[Devarsh Thakkar]

This overlay needs to be used with display sharing supported device
manager firmware only.

Remote core running this firmware has write access to "common" register
space, VIDL pipeline, OVR1 overlay and VP1 videoport.

The processing core running Linux is provided write access to VID
pipeline and "common1" register space.

The VP1 video port is shared between Linux and remote core with remote
core configuring the overlay manager to set Zorder 1 for VID pipeline
and Zorder 2 for VIDL pipeline.

Add reserved memory region for framebuffer region used by remote core in
dss shared mode overlay file so that Linux does not re-use the same
while allocating memory.

Also add a label for reserved memory region in base device-tree file so
that it can be referred back in overlay file.

Signed-off-by: Devarsh Thakkar <devarsht at ti.com>
---
 arch/arm64/boot/dts/ti/Makefile               |  1 +
 .../arm64/boot/dts/ti/k3-am62x-sk-common.dtsi |  2 +-
 .../dts/ti/k3-am62x-sk-dss-shared-mode.dtso   | 33 +++++++++++++++++++
 3 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 arch/arm64/boot/dts/ti/k3-am62x-sk-dss-shared-mode.dtso

diff --git a/arch/arm64/boot/dts/ti/Makefile b/arch/arm64/boot/dts/ti/Makefile
index 52c1dc910308..ff832741b367 100644
--- a/arch/arm64/boot/dts/ti/Makefile
+++ b/arch/arm64/boot/dts/ti/Makefile
@@ -35,6 +35,7 @@ dtb-$(CONFIG_ARCH_K3) += k3-am62x-sk-csi2-ov5640.dtbo
 dtb-$(CONFIG_ARCH_K3) += k3-am62x-sk-csi2-tevi-ov5640.dtbo
 dtb-$(CONFIG_ARCH_K3) += k3-am62x-sk-csi2-imx219.dtbo
 dtb-$(CONFIG_ARCH_K3) += k3-am62x-sk-hdmi-audio.dtbo
+dtb-$(CONFIG_ARCH_K3) += k3-am62x-sk-dss-shared-mode.dtbo
 
 # Boards with AM64x SoC
 dtb-$(CONFIG_ARCH_K3) += k3-am642-evm.dtb
diff --git a/arch/arm64/boot/dts/ti/k3-am62x-sk-common.dtsi b/arch/arm64/boot/dts/ti/k3-am62x-sk-common.dtsi
index 33768c02d8eb..8b55ca10102f 100644
--- a/arch/arm64/boot/dts/ti/k3-am62x-sk-common.dtsi
+++ b/arch/arm64/boot/dts/ti/k3-am62x-sk-common.dtsi
@@ -34,7 +34,7 @@ memory at 80000000 {
 		reg = <0x00000000 0x80000000 0x00000000 0x80000000>;
 	};
 
-	reserved-memory {
+	reserved_memory: reserved-memory {
 		#address-cells = <2>;
 		#size-cells = <2>;
 		ranges;
diff --git a/arch/arm64/boot/dts/ti/k3-am62x-sk-dss-shared-mode.dtso b/arch/arm64/boot/dts/ti/k3-am62x-sk-dss-shared-mode.dtso
new file mode 100644
index 000000000000..02153748a5c2
--- /dev/null
+++ b/arch/arm64/boot/dts/ti/k3-am62x-sk-dss-shared-mode.dtso
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0
+/**
+ * DT overlay to enable display sharing mode for AM62P DSS0
+ * This is compatible with custom AM62 Device Manager firmware
+ *
+ * Copyright (C) 2023 Texas Instruments Incorporated - http://www.ti.com/
+ */
+
+/dts-v1/;
+/plugin/;
+
+#include <dt-bindings/interrupt-controller/irq.h>
+#include <dt-bindings/interrupt-controller/arm-gic.h>
+
+&dss0 {
+	ti,dss-shared-mode;
+	ti,dss-shared-mode-vp = "vp1";
+	ti,dss-shared-mode-vp-owned = <0>;
+	ti,dss-shared-mode-common = "common1";
+	ti,dss-shared-mode-planes = "vid";
+	ti,dss-shared-mode-plane-zorder = <0>;
+	interrupts = <GIC_SPI 85 IRQ_TYPE_LEVEL_HIGH>;
+};
+
+&reserved_memory {
+	#address-cells = <2>;
+	#size-cells = <2>;
+	rtos_framebuffer_memory_region: rtos-framebuffer-memory at 94800000 {
+		compatible = "shared-dma-pool";
+		reg = <0x00 0x94800000 0x00 0x08000000>;
+		no-map;
+	};
+};
-- 
2.34.1