Re: [PATCH 2/2] arm64: dts: qcom: talos: Add EL2 overlay

[Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>]

On 1/23/26 11:35 AM, Mukesh Ojha wrote:
> 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
> 
> Signed-off-by: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>
> ---
> This patch has dependency on https://lore.kernel.org/lkml/20260121-qcs615-spin-2-v7-0-52419b263e92@oss.qualcomm.com/#t
> which adds gpu_zap_shader.
> 
> 
>  arch/arm64/boot/dts/qcom/Makefile       |  4 ++++
>  arch/arm64/boot/dts/qcom/talos-el2.dtso | 28 +++++++++++++++++++++++++
>  2 files changed, 32 insertions(+)
>  create mode 100644 arch/arm64/boot/dts/qcom/talos-el2.dtso
> 
> diff --git a/arch/arm64/boot/dts/qcom/Makefile b/arch/arm64/boot/dts/qcom/Makefile
> index cbf7d89e432c..48ecbea17a4e 100644
> --- a/arch/arm64/boot/dts/qcom/Makefile
> +++ b/arch/arm64/boot/dts/qcom/Makefile
> @@ -141,6 +141,10 @@ 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-radxa-dragon-q6a.dtb
>  dtb-$(CONFIG_ARCH_QCOM)	+= qcs6490-rb3gen2.dtb
>  
> diff --git a/arch/arm64/boot/dts/qcom/talos-el2.dtso b/arch/arm64/boot/dts/qcom/talos-el2.dtso
> new file mode 100644
> index 000000000000..03ca04c44976
> --- /dev/null
> +++ b/arch/arm64/boot/dts/qcom/talos-el2.dtso
> @@ -0,0 +1,28 @@
> +// SPDX-License-Identifier: BSD-3-Clause
> +/*
> + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
> + */
> +
> +/*
> + * Talos specific modifications required to boot in EL2.

Preferably merge it with the previous comment, separated by a newline
after the copyright

otherwise

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

Konrad