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/dc.c b/drivers/gpu/drm/tegra/dc.c
index 4a01523..5f138b7 100644
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c
@@ -9,6 +9,7 @@
#include <linux/clk.h>
#include <linux/debugfs.h>
+#include <linux/iommu.h>
#include <linux/reset.h>
#include <soc/tegra/pmc.h>
@@ -1290,6 +1291,17 @@
struct tegra_drm *tegra = drm->dev_private;
int err;
+ if (tegra->domain) {
+ err = iommu_attach_device(tegra->domain, dc->dev);
+ if (err < 0) {
+ dev_err(dc->dev, "failed to attach to domain: %d\n",
+ err);
+ return err;
+ }
+
+ dc->domain = tegra->domain;
+ }
+
drm_crtc_init(drm, &dc->base, &tegra_crtc_funcs);
drm_mode_crtc_set_gamma_size(&dc->base, 256);
drm_crtc_helper_add(&dc->base, &tegra_crtc_helper_funcs);
@@ -1347,6 +1359,11 @@
return err;
}
+ if (dc->domain) {
+ iommu_detach_device(dc->domain, dc->dev);
+ dc->domain = NULL;
+ }
+
return 0;
}