Re: [PATCH] arm64: dts: qcom: shikra: Add EL2 overlay for remoteproc SMMU mappings

[Komal Bajaj <komal.bajaj@oss.qualcomm.com>]

On 9/18/2026 6:04 PM, Komal Bajaj wrote:
> Shikra boards currently boot Linux under a hypervisor, where the
> remote processor firmware IOMMU streams are managed by the hypervisor.
> When booting Linux directly at EL2 without the hypervisor, the IOMMU
> is instead managed by the consumer of this DeviceTree, so the firmware
> streams for each remote processor need to be described explicitly.
>
> Add an EL2-specific DT overlay and apply it to all Shikra EVK variants
> devices to produce an -el2.dtb alongside the "normal" dtb.
>
> Co-developed-by: Bibek Kumar Patro <bibek.patro@oss.qualcomm.com>
> Signed-off-by: Bibek Kumar Patro <bibek.patro@oss.qualcomm.com>
> Signed-off-by: Komal Bajaj <komal.bajaj@oss.qualcomm.com>
> ---
> All existing Shikra EVK board variants boot Linux under a hypervisor,
> which means Linux typically runs at EL1. For EL2 boot without the
> hypervisor, remote processor firmware IOMMU streams must be described in
> the DeviceTree consumed by Linux.
>
> Add a Shikra EL2-specific DT overlay and wire it up in the Makefile to
> produce -el2.dtb artifacts for the Shikra EVK variants alongside the
> regular dtbs.
>
> Komal Bajaj (1):
>    arm64: dts: qcom: shikra: Add EL2 overlay for remoteproc SMMU mappings
>
>   arch/arm64/boot/dts/qcom/Makefile        | 12 ++++++++++++
>   arch/arm64/boot/dts/qcom/shikra-el2.dtso | 23 +++++++++++++++++++++++
>   2 files changed, 35 insertions(+)
>   create mode 100644 arch/arm64/boot/dts/qcom/shikra-el2.dtso
> ---
>   arch/arm64/boot/dts/qcom/Makefile        | 12 ++++++++++++
>   arch/arm64/boot/dts/qcom/shikra-el2.dtso | 23 +++++++++++++++++++++++
>   2 files changed, 35 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/qcom/Makefile b/arch/arm64/boot/dts/qcom/Makefile
> index 5c19f945c785..686d37cab02f 100644
> --- a/arch/arm64/boot/dts/qcom/Makefile
> +++ b/arch/arm64/boot/dts/qcom/Makefile
> @@ -359,8 +359,20 @@ dtb-$(CONFIG_ARCH_QCOM)	+= sdm850-lenovo-yoga-c630.dtb
>   dtb-$(CONFIG_ARCH_QCOM)	+= sdm850-samsung-w737.dtb
>   dtb-$(CONFIG_ARCH_QCOM)	+= sdx75-idp.dtb
>   dtb-$(CONFIG_ARCH_QCOM)	+= shikra-cqm-evk.dtb
> +
> +shikra-cqm-evk-el2-dtbs	:= shikra-cqm-evk.dtb shikra-el2.dtbo
> +dtb-$(CONFIG_ARCH_QCOM)	+= shikra-cqm-evk-el2.dtb
> +
>   dtb-$(CONFIG_ARCH_QCOM)	+= shikra-cqs-evk.dtb
> +
> +shikra-cqs-evk-el2-dtbs	:= shikra-cqs-evk.dtb shikra-el2.dtbo
> +dtb-$(CONFIG_ARCH_QCOM)	+= shikra-cqs-evk-el2.dtb
> +
>   dtb-$(CONFIG_ARCH_QCOM)	+= shikra-iqs-evk.dtb
> +
> +shikra-iqs-evk-el2-dtbs	:= shikra-iqs-evk.dtb shikra-el2.dtbo
> +dtb-$(CONFIG_ARCH_QCOM)	+= shikra-iqs-evk-el2.dtb
> +
>   dtb-$(CONFIG_ARCH_QCOM)	+= sm4250-oneplus-billie2.dtb
>   dtb-$(CONFIG_ARCH_QCOM)	+= sm4450-qrd.dtb
>   dtb-$(CONFIG_ARCH_QCOM)	+= sm6115-fxtec-pro1x.dtb
> diff --git a/arch/arm64/boot/dts/qcom/shikra-el2.dtso b/arch/arm64/boot/dts/qcom/shikra-el2.dtso
> new file mode 100644
> index 000000000000..d2f3186bd47d
> --- /dev/null
> +++ b/arch/arm64/boot/dts/qcom/shikra-el2.dtso
> @@ -0,0 +1,23 @@
> +// SPDX-License-Identifier: BSD-3-Clause
> +/*
> + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
> + *
> + * Shikra specific modifications required to boot in EL2.
> + */
> +
> +/dts-v1/;
> +/plugin/;
> +
> +&gpu_zap_shader {
> +	status = "disabled";
> +};
> +
> +&remoteproc_cdsp {
> +	iommus = <&apps_smmu 0x0200 0x0>;
> +};
> +
> +&remoteproc_lpaicp {
> +	iommus = <&apps_smmu 0x0360 0x0005>,
> +		 <&apps_smmu 0x0366 0x0000>,
> +		 <&apps_smmu 0x00e7 0x0000>;
> +};

Please ignore this patch. With this change, DT schema validation error 
is being reported:

   from schema $id: 
http://devicetree.org/schemas/remoteproc/qcom,shikra-pas.yaml
   arch/arm64/boot/dts/qcom/shikra-cqs-evk-el2.dtb:
   remoteproc@b800000 (qcom,shikra-lpaicp-pas): iommus: [[41, 864, 5], 
[41, 870, 0], [41, 231, 0]] is too long

I have posted a v2 [1] of the patch series to address DT schema 
validation warning.

[1] 
https://lore.kernel.org/all/20260930-shikra-el2-v2-0-f0822be5aaee@oss.qualcomm.com/

Thanks
Komal

>
> ---
> base-commit: e657a464aba873f5eaf3ca821b6e4016674492d6
> change-id: 20260918-shikra-el2-ea8969385c3c
>
> Best regards,