Re: [PATCH v6] iommu/arm-smmu-qcom: Request direct mapping for modem device

Stephen Boyd
2020-05-11T19:37:32Z

Quoting Sibi Sankar (2020-05-11 10:55:32)
> The modem remote processor has two access paths to DDR. One path is
> directly connected to DDR and another path goes through an SMMU. The
> SMMU path is configured to be a direct mapping because it's used by
> various peripherals in the modem subsystem. Typically this direct
> mapping is configured statically at EL2 by QHEE (Qualcomm's Hypervisor
> Execution Environment) before the kernel is entered.
>
> In certain firmware configuration, especially when the kernel is already
> in full control of the SMMU, defer programming the modem SIDs to the
> kernel. Let's add compatibles here so that we can have the kernel
> program the SIDs for the modem in these cases.
>
> Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
> ---

Reviewed-by: Stephen Boyd <swboyd@chromium.org>