drm/tegra: Add IOMMU support
When an IOMMU device is available on the platform bus, allocate an IOMMU
domain and attach the display controllers to it. The display controllers
can then scan out non-contiguous buffers by mapping them through the
IOMMU.
Signed-off-by: Thierry Reding <treding@nvidia.com>
diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
index e1632fb..6c9df79 100644
--- a/drivers/gpu/drm/tegra/drm.c
+++ b/drivers/gpu/drm/tegra/drm.c
@@ -8,6 +8,7 @@
*/
#include <linux/host1x.h>
+#include <linux/iommu.h>
#include "drm.h"
#include "gem.h"
@@ -33,6 +34,17 @@
if (!tegra)
return -ENOMEM;
+ if (iommu_present(&platform_bus_type)) {
+ tegra->domain = iommu_domain_alloc(&platform_bus_type);
+ if (IS_ERR(tegra->domain)) {
+ err = PTR_ERR(tegra->domain);
+ goto free;
+ }
+
+ DRM_DEBUG("IOMMU context initialized\n");
+ drm_mm_init(&tegra->mm, 0, SZ_2G);
+ }
+
mutex_init(&tegra->clients_lock);
INIT_LIST_HEAD(&tegra->clients);
drm->dev_private = tegra;
@@ -76,6 +88,12 @@
tegra_drm_fb_free(drm);
config:
drm_mode_config_cleanup(drm);
+
+ if (tegra->domain) {
+ iommu_domain_free(tegra->domain);
+ drm_mm_takedown(&tegra->mm);
+ }
+free:
kfree(tegra);
return err;
}
@@ -83,6 +101,7 @@
static int tegra_drm_unload(struct drm_device *drm)
{
struct host1x_device *device = to_host1x_device(drm->dev);
+ struct tegra_drm *tegra = drm->dev_private;
int err;
drm_kms_helper_poll_fini(drm);
@@ -94,6 +113,11 @@
if (err < 0)
return err;
+ if (tegra->domain) {
+ iommu_domain_free(tegra->domain);
+ drm_mm_takedown(&tegra->mm);
+ }
+
return 0;
}