Re: [PATCH v8 13/14] remoteproc: qcom: pas: Enable Secure PAS support with IOMMU managed by Linux

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

On 11/21/25 12:01 PM, Mukesh Ojha wrote:
> Most Qualcomm platforms feature Gunyah hypervisor, which typically
> handles IOMMU configuration. This includes mapping memory regions and
> device memory resources for remote processors by intercepting
> qcom_scm_pas_auth_and_reset() calls. These mappings are later removed
> during teardown. Additionally, SHM bridge setup is required to enable
> memory protection for both remoteproc metadata and its memory regions.
> When the aforementioned hypervisor is absent, the operating system must
> perform these configurations instead.
> 
> When Linux runs as the hypervisor (@ EL2) on a SoC, it will have its
> own device tree overlay file that specifies the firmware stream ID now
> managed by Linux for a particular remote processor. If the iommus
> property is specified in the remoteproc device tree node, it indicates
> that IOMMU configuration must be handled by Linux. In this case, the
> has_iommu flag is set for the remote processor, which ensures that the
> resource table, carveouts, and SHM bridge are properly configured before
> memory is passed to TrustZone for authentication. Otherwise, the
> has_iommu flag remains unset, which indicates default behavior.
> 
> Enables Secure PAS support for remote processors when IOMMU configuration
> is managed by Linux.
> 
> Signed-off-by: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>
> ---

[...]

> +	pas->pas_ctx->has_iommu = rproc->has_iommu;
> +	pas->dtb_pas_ctx->has_iommu = rproc->has_iommu;

Sorry if we've been there before, but I see that IOMMU-mapping happens
before ctx initialization.. can we drop this parameter and just use
device_iommu_mapped(ctx->dev) in qcom_scm_pas_prepare_and_auth_reset()?