From: Dmitry Osipenko digetx@gmail.com
commit d210919dbdc8a82c676cc3e3c370b1802be63124 upstream.
DMA buffers of 2D/3D engines aren't mapped properly when CONFIG_ARM_DMA_USE_IOMMU=y. The memory management code of Tegra DRM driver has a longstanding overhaul overdue and it's not obvious where the problem is in this case. Hence let's add back the old workaround which we already had sometime before. It explicitly detaches DRM devices from the offending implicit IOMMU domain. This fixes a completely broken 2d/3d drivers in case of ARM32 multiplatform kernel config.
Cc: stable@vger.kernel.org Fixes: fa6661b7aa0b ("drm/tegra: Optionally attach clients to the IOMMU") Signed-off-by: Dmitry Osipenko digetx@gmail.com Signed-off-by: Thierry Reding treding@nvidia.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/tegra/drm.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)
--- a/drivers/gpu/drm/tegra/drm.c +++ b/drivers/gpu/drm/tegra/drm.c @@ -21,6 +21,10 @@ #include <drm/drm_prime.h> #include <drm/drm_vblank.h>
+#if IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU) +#include <asm/dma-iommu.h> +#endif + #include "dc.h" #include "drm.h" #include "gem.h" @@ -936,6 +940,17 @@ int host1x_client_iommu_attach(struct ho struct iommu_group *group = NULL; int err;
+#if IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU) + if (client->dev->archdata.mapping) { + struct dma_iommu_mapping *mapping = + to_dma_iommu_mapping(client->dev); + arm_iommu_detach_device(client->dev); + arm_iommu_release_mapping(mapping); + + domain = iommu_get_domain_for_dev(client->dev); + } +#endif + /* * If the host1x client is already attached to an IOMMU domain that is * not the shared IOMMU domain, don't try to attach it to a different