drm: Introduce a drm_crtc_commit_wait helper

There's currently four users of the same logic to wait for a commit to
be flipped: three for the CRTCs, connectors and planes in
drm_atomic_helper_wait_for_dependencies, and one in vc4.

Let's consolidate this a bit to avoid any code duplication.

Suggested-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20210111084401.117152-1-maxime@cerno.tech

1 files changed, 39 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index dda60051854b..b1efa9322be2 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -53,6 +53,45 @@ void __drm_crtc_commit_free(struct kref *kref)
 EXPORT_SYMBOL(__drm_crtc_commit_free);
 
 /**
+ * drm_crtc_commit_wait - Waits for a commit to complete
+ * @commit: &drm_crtc_commit to wait for
+ *
+ * Waits for a given &drm_crtc_commit to be programmed into the
+ * hardware and flipped to.
+ *
+ * Returns:
+ *
+ * 0 on success, a negative error code otherwise.
+ */
+int drm_crtc_commit_wait(struct drm_crtc_commit *commit)
+{
+	unsigned long timeout = 10 * HZ;
+	int ret;
+
+	if (!commit)
+		return 0;
+
+	ret = wait_for_completion_timeout(&commit->hw_done, timeout);
+	if (!ret) {
+		DRM_ERROR("hw_done timed out\n");
+		return -ETIMEDOUT;
+	}
+
+	/*
+	 * Currently no support for overwriting flips, hence
+	 * stall for previous one to execute completely.
+	 */
+	ret = wait_for_completion_timeout(&commit->flip_done, timeout);
+	if (!ret) {
+		DRM_ERROR("flip_done timed out\n");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_crtc_commit_wait);
+
+/**
  * drm_atomic_state_default_release -
  * release memory initialized by drm_atomic_state_init
  * @state: atomic state