[WIP] drm/panfrost: Set IOMMU_CACHE flag on page faults

Suggested by Boris; Panfrost does not support uncached mappings, so also
flag the pages that are mapped as response to a page fault as cached.

TODO:
  * Merge with other patches from Ariel
  * Do a full CI run to check for regressions on G52

Signed-off-by: Sjoerd Simons <sjoerd@collabora.com>

drivers/gpu/drm/panfrost/panfrost_mmu.c

@@ -598,7 +598,7 @@ static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as,
 		goto err_map;
 
 	mmu_map_sg(pfdev, bomapping->mmu, addr,
-		   IOMMU_WRITE | IOMMU_READ | IOMMU_NOEXEC, sgt);
+		   IOMMU_WRITE | IOMMU_READ | IOMMU_CACHE | IOMMU_NOEXEC, sgt);
 
 	bomapping->active = true;
 	bo->heap_rss_size += SZ_2M;