1 files changed, 148 insertions, 1 deletions

diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c
index 2e5597d10cc6..f95f2df5f8d1 100644
--- a/drivers/gpu/drm/vc4/vc4_kms.c
+++ b/drivers/gpu/drm/vc4/vc4_kms.c
@@ -15,6 +15,7 @@
  */
 
 #include "drm_crtc.h"
+#include "drm_atomic.h"
 #include "drm_atomic_helper.h"
 #include "drm_crtc_helper.h"
 #include "drm_plane_helper.h"
@@ -29,10 +30,152 @@ static void vc4_output_poll_changed(struct drm_device *dev)
 		drm_fbdev_cma_hotplug_event(vc4->fbdev);
 }
 
+struct vc4_commit {
+	struct drm_device *dev;
+	struct drm_atomic_state *state;
+	struct vc4_seqno_cb cb;
+};
+
+static void
+vc4_atomic_complete_commit(struct vc4_commit *c)
+{
+	struct drm_atomic_state *state = c->state;
+	struct drm_device *dev = state->dev;
+	struct vc4_dev *vc4 = to_vc4_dev(dev);
+
+	drm_atomic_helper_commit_modeset_disables(dev, state);
+
+	drm_atomic_helper_commit_planes(dev, state, false);
+
+	drm_atomic_helper_commit_modeset_enables(dev, state);
+
+	drm_atomic_helper_wait_for_vblanks(dev, state);
+
+	drm_atomic_helper_cleanup_planes(dev, state);
+
+	drm_atomic_state_free(state);
+
+	up(&vc4->async_modeset);
+
+	kfree(c);
+}
+
+static void
+vc4_atomic_complete_commit_seqno_cb(struct vc4_seqno_cb *cb)
+{
+	struct vc4_commit *c = container_of(cb, struct vc4_commit, cb);
+
+	vc4_atomic_complete_commit(c);
+}
+
+static struct vc4_commit *commit_init(struct drm_atomic_state *state)
+{
+	struct vc4_commit *c = kzalloc(sizeof(*c), GFP_KERNEL);
+
+	if (!c)
+		return NULL;
+	c->dev = state->dev;
+	c->state = state;
+
+	return c;
+}
+
+/**
+ * vc4_atomic_commit - commit validated state object
+ * @dev: DRM device
+ * @state: the driver state object
+ * @async: asynchronous commit
+ *
+ * This function commits a with drm_atomic_helper_check() pre-validated state
+ * object. This can still fail when e.g. the framebuffer reservation fails. For
+ * now this doesn't implement asynchronous commits.
+ *
+ * RETURNS
+ * Zero for success or -errno.
+ */
+static int vc4_atomic_commit(struct drm_device *dev,
+			     struct drm_atomic_state *state,
+			     bool async)
+{
+	struct vc4_dev *vc4 = to_vc4_dev(dev);
+	int ret;
+	int i;
+	uint64_t wait_seqno = 0;
+	struct vc4_commit *c;
+
+	c = commit_init(state);
+	if (!c)
+		return -ENOMEM;
+
+	/* Make sure that any outstanding modesets have finished. */
+	ret = down_interruptible(&vc4->async_modeset);
+	if (ret) {
+		kfree(c);
+		return ret;
+	}
+
+	ret = drm_atomic_helper_prepare_planes(dev, state);
+	if (ret) {
+		kfree(c);
+		up(&vc4->async_modeset);
+		return ret;
+	}
+
+	for (i = 0; i < dev->mode_config.num_total_plane; i++) {
+		struct drm_plane *plane = state->planes[i];
+		struct drm_plane_state *new_state = state->plane_states[i];
+
+		if (!plane)
+			continue;
+
+		if ((plane->state->fb != new_state->fb) && new_state->fb) {
+			struct drm_gem_cma_object *cma_bo =
+				drm_fb_cma_get_gem_obj(new_state->fb, 0);
+			struct vc4_bo *bo = to_vc4_bo(&cma_bo->base);
+
+			wait_seqno = max(bo->seqno, wait_seqno);
+		}
+	}
+
+	/*
+	 * This is the point of no return - everything below never fails except
+	 * when the hw goes bonghits. Which means we can commit the new state on
+	 * the software side now.
+	 */
+
+	drm_atomic_helper_swap_state(dev, state);
+
+	/*
+	 * Everything below can be run asynchronously without the need to grab
+	 * any modeset locks at all under one condition: It must be guaranteed
+	 * that the asynchronous work has either been cancelled (if the driver
+	 * supports it, which at least requires that the framebuffers get
+	 * cleaned up with drm_atomic_helper_cleanup_planes()) or completed
+	 * before the new state gets committed on the software side with
+	 * drm_atomic_helper_swap_state().
+	 *
+	 * This scheme allows new atomic state updates to be prepared and
+	 * checked in parallel to the asynchronous completion of the previous
+	 * update. Which is important since compositors need to figure out the
+	 * composition of the next frame right after having submitted the
+	 * current layout.
+	 */
+
+	if (async) {
+		vc4_queue_seqno_cb(dev, &c->cb, wait_seqno,
+				   vc4_atomic_complete_commit_seqno_cb);
+	} else {
+		vc4_wait_for_seqno(dev, wait_seqno, ~0ull, false);
+		vc4_atomic_complete_commit(c);
+	}
+
+	return 0;
+}
+
 static const struct drm_mode_config_funcs vc4_mode_funcs = {
 	.output_poll_changed = vc4_output_poll_changed,
 	.atomic_check = drm_atomic_helper_check,
-	.atomic_commit = drm_atomic_helper_commit,
+	.atomic_commit = vc4_atomic_commit,
 	.fb_create = drm_fb_cma_create,
 };
 
@@ -41,6 +184,8 @@ int vc4_kms_load(struct drm_device *dev)
 	struct vc4_dev *vc4 = to_vc4_dev(dev);
 	int ret;
 
+	sema_init(&vc4->async_modeset, 1);
+
 	ret = drm_vblank_init(dev, dev->mode_config.num_crtc);
 	if (ret < 0) {
 		dev_err(dev->dev, "failed to initialize vblank\n");
@@ -51,6 +196,8 @@ int vc4_kms_load(struct drm_device *dev)
 	dev->mode_config.max_height = 2048;
 	dev->mode_config.funcs = &vc4_mode_funcs;
 	dev->mode_config.preferred_depth = 24;
+	dev->mode_config.async_page_flip = true;
+
 	dev->vblank_disable_allowed = true;
 
 	drm_mode_config_reset(dev);