remoteproc: omap: Handle ARM dma_iommu_mapping

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: 4720287 ("iommu: Remove struct iommu_ops *iommu from arch_setup_dma_ops()")
Signed-off-by: Robin Murphy <[email protected]>
Tested-by: Beleswar Padhi <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/6186e311cb6f64a787f87fd41e49a73f409b789c.1730136799.git.robin.murphy@arm.com
[Fixed changelog title]
Signed-off-by: Mathieu Poirier <[email protected]>

Author: rmurphy-arm

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
+
 	ret = omap_rproc_of_get_internal_memories(pdev, rproc);
 	if (ret)
 		return ret;