All Tegra DRM devices are getting attached to an implicit IOMMU DMA
domain if CONFIG_ARM_DMA_USE_IOMMU=y. Since Tegra DRM driver manages IOMMU
by itself, the devices must be detached from the implicit domain using
arch-specific IOMMU-API. Note that this works only for arm32 and not for
arm64, which will remain broken if CONFIG_IOMMU_DMA is enabled.
Signed-off-by: Dmitry Osipenko <dig...@gmail.com>
---
drivers/gpu/drm/tegra/drm.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
index a2bd5876c633..b2ac2411e0ff 100644
--- a/drivers/gpu/drm/tegra/drm.c
+++ b/drivers/gpu/drm/tegra/drm.c
@@ -15,6 +15,10 @@
#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
+#if IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)
+#include <asm/dma-iommu.h>
+#endif
+
#include "drm.h"
#include "gem.h"
@@ -1068,6 +1072,14 @@ struct iommu_group *host1x_client_iommu_attach(struct
host1x_client *client,
}
if (!shared || (shared && (group != tegra->group))) {
+#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);
+ }
+#endif
err = iommu_attach_group(tegra->domain, group);
if (err < 0) {
iommu_group_put(group);
--
2.18.0
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