Re: [PATCH 1/4] remoteproc/omap: Handle ARM dma_iommu_mapping

[Mathieu Poirier <mathieu.poirier@linaro.org>]

On Mon, Oct 28, 2024 at 05:58:35PM +0000, Robin Murphy wrote:
> It's no longer practical for the OMAP IOMMU driver to trick
> arm_setup_iommu_dma_ops() into ignoring its presence, so let's use the
> same tactic as other IOMMU API users on 32-bit ARM and explicitly kick
> the arch code's dma_iommu_mapping out of the way to avoid problems.
> 
> Fixes: 4720287c7bf7 ("iommu: Remove struct iommu_ops *iommu from arch_setup_dma_ops()")
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> ---
>  drivers/remoteproc/omap_remoteproc.c | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/drivers/remoteproc/omap_remoteproc.c b/drivers/remoteproc/omap_remoteproc.c
> index 9ae2e831456d..3260dd512491 100644
> --- a/drivers/remoteproc/omap_remoteproc.c
> +++ b/drivers/remoteproc/omap_remoteproc.c
> @@ -37,6 +37,10 @@
>  
>  #include <linux/platform_data/dmtimer-omap.h>
>  
> +#ifdef CONFIG_ARM_DMA_USE_IOMMU
> +#include <asm/dma-iommu.h>
> +#endif
> +
>  #include "omap_remoteproc.h"
>  #include "remoteproc_internal.h"
>  
> @@ -1323,6 +1327,19 @@ static int omap_rproc_probe(struct platform_device *pdev)
>  	/* All existing OMAP IPU and DSP processors have an MMU */
>  	rproc->has_iommu = true;
>  
> +#ifdef CONFIG_ARM_DMA_USE_IOMMU
> +	/*
> +	 * Throw away the ARM DMA mapping that we'll never use, so it doesn't
> +	 * interfere with the core rproc->domain and we get the right DMA ops.
> +	 */
> +	if (pdev->dev.archdata.mapping) {
> +		struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(&pdev->dev);
> +
> +		arm_iommu_detach_device(&pdev->dev);
> +		arm_iommu_release_mapping(mapping);
> +	}
> +#endif
> +

Despite acknowledging this patch I never applied it, something I have corrected
now.

Thanks for Beleswar for bringing this to my attention.

Regards,
Mathieu

>  	ret = omap_rproc_of_get_internal_memories(pdev, rproc);
>  	if (ret)
>  		return ret;
> -- 
> 2.39.2.101.g768bb238c484.dirty
>