FROMLIST: arm64: dts: qcom: talos: Add EL2 overlay

All the existing variants Talos boards are using Gunyah hypervisor
which means that, so far, Linux-based OS could only boot in EL1 on
those devices.  However, it is possible for us to boot Linux at EL2
on these devices [1].

When running under Gunyah, the remote processor firmware IOMMU streams
are controlled by Gunyah. However, without Gunyah, the IOMMU is managed
by the consumer of this DeviceTree. Therefore, describe the firmware
streams for each remote processor.

Add a EL2-specific DT overlay and apply it to Talos IOT variant
devices to create -el2.dtb for each of them alongside "normal" dtb.

[1]
https://docs.qualcomm.com/bundle/publicresource/topics/80-70020-4/boot-developer-touchpoints.html#uefi

Link: https://lore.kernel.org/lkml/20260127-talos-el2-overlay-v2-3-b6a2266532c4@oss.qualcomm.com/
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>

Author: mukeshojha-linux

arch/arm64/boot/dts/qcom/Makefile

@@ -146,6 +146,11 @@ dtb-$(CONFIG_ARCH_QCOM)	+= qcm6490-shift-otter.dtb
 dtb-$(CONFIG_ARCH_QCOM)	+= qcs404-evb-1000.dtb
 dtb-$(CONFIG_ARCH_QCOM)	+= qcs404-evb-4000.dtb
 dtb-$(CONFIG_ARCH_QCOM)	+= qcs615-ride.dtb
+
+qcs615-ride-el2-dtbs := qcs615-ride.dtb talos-el2.dtbo
+
+dtb-$(CONFIG_ARCH_QCOM)	+= qcs615-ride-el2.dtb
+
 dtb-$(CONFIG_ARCH_QCOM)	+= qcs6490-rb3gen2.dtb
 
 qcs6490-rb3gen2-vision-mezzanine-dtbs := qcs6490-rb3gen2.dtb qcs6490-rb3gen2-vision-mezzanine.dtbo

arch/arm64/boot/dts/qcom/talos-el2.dtso

@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: BSD-3-Clause
+/*
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+
+ * Talos specific modifications required to boot in EL2.
+ */
+
+/dts-v1/;
+/plugin/;
+
+&gpu_zap_shader {
+	status = "disabled";
+};
+
+&remoteproc_adsp {
+	iommus = <&apps_smmu 0x1720 0x0>;
+};
+
+&remoteproc_cdsp {
+	iommus = <&apps_smmu 0x1080 0x0>;
+};
+
+&venus {
+	status = "disabled";
+};