Re: [PATCH RESEND v10 2/2] arm64: dts: qcom: kodiak: Add EL2 overlay

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

On 7/14/26 9:19 AM, Mukesh Ojha wrote:
> All existing Kodiak board variants run the Gunyah hypervisor, which
> means Linux can only boot at EL1 on those devices. It is possible to
> boot Linux at EL2 on these devices [1].
> 
> When running under Gunyah, remote processor firmware IOMMU streams are
> controlled by Gunyah. Without Gunyah, the IOMMU is managed by the
> consumer of the DeviceTree. Describe the firmware streams for each
> remote processor in an EL2 overlay.
> 
> Add an EL2-specific DT overlay and apply it to Kodiak IoT variant
> devices to produce a -el2.dtb alongside the standard dtb. Modem and
> media subsystems are not yet supported due to missing dependencies.
> The GPU zap shader is disabled. In EL2 mode the kernel owns the
> hardware watchdog, so it is enabled here. The wifi-firmware child
> node describes the IOMMU stream for the WCN6750 firmware; the &wifi
> node itself is left untouched so that platforms without WiFi are
> unaffected by the overlay.
> 
> [1] https://docs.qualcomm.com/bundle/publicresource/topics/80-70020-4/boot-developer-touchpoints.html#uefi
> 
> Co-developed-by: Sumit Garg <sumit.garg@oss.qualcomm.com>
> Signed-off-by: Sumit Garg <sumit.garg@oss.qualcomm.com>
> Signed-off-by: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>
> ---

If gunyah reserves gpu_zap_mem, we could probably shave it off too

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

Konrad