On Fri, May 15, 2026 at 03:35:29PM -0500, Aaron Kling via B4 Relay wrote:
> From: Aaron Kling <webgeek1234@gmail.com>
> 
> Without iommu and dma enabled, flash storage such as the spi-nor on the
> p3668 module times out and cannot complete any transfers.
> 
> Signed-off-by: Aaron Kling <webgeek1234@gmail.com>
> ---
>  arch/arm64/boot/dts/nvidia/tegra194.dtsi | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/nvidia/tegra194.dtsi b/arch/arm64/boot/dts/nvidia/tegra194.dtsi
> index 1d659454a6f9fe..0e0a20befe9e68 100644
> --- a/arch/arm64/boot/dts/nvidia/tegra194.dtsi
> +++ b/arch/arm64/boot/dts/nvidia/tegra194.dtsi
> @@ -923,6 +923,10 @@ spi@3270000 {
>  				 <&bpmp TEGRA194_CLK_QSPI0_PM>;
>  			clock-names = "qspi", "qspi_out";
>  			resets = <&bpmp TEGRA194_RESET_QSPI0>;
> +			iommus = <&smmu TEGRA194_SID_GPCDMA_0>;
> +			dma-coherent;
> +			dmas = <&gpcdma 5>, <&gpcdma 5>;
> +			dma-names = "rx", "tx";

dmas and dma-names are the only properties that you should need here.

Thierry