drm/sti: add debugfs fps_show/fps_get mechanism for planes

Display fps on demand for each used plane:
cat /sys/kernel/debug/dri/0/fps_get
Display fps in live in the console for each used plane:
echo 255 > /sys/kernel/debug/dri/0/fps_show

Signed-off-by: Vincent Abriou <vincent.abriou@st.com>
Reviewed-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>

1 files changed, 63 insertions, 0 deletions

diff --git a/drivers/gpu/drm/sti/sti_plane.c b/drivers/gpu/drm/sti/sti_plane.c
index 2e5c751910c5..f10c98d3f012 100644
--- a/drivers/gpu/drm/sti/sti_plane.c
+++ b/drivers/gpu/drm/sti/sti_plane.c
@@ -43,6 +43,69 @@ const char *sti_plane_to_str(struct sti_plane *plane)
 	}
 }
 
+#define STI_FPS_INTERVAL_MS     3000
+
+static int sti_plane_timespec_ms_diff(struct timespec lhs, struct timespec rhs)
+{
+	struct timespec tmp_ts = timespec_sub(lhs, rhs);
+	u64 tmp_ns = (u64)timespec_to_ns(&tmp_ts);
+
+	do_div(tmp_ns, NSEC_PER_MSEC);
+
+	return (u32)tmp_ns;
+}
+
+void sti_plane_update_fps(struct sti_plane *plane,
+			  bool new_frame,
+			  bool new_field)
+{
+	struct timespec now;
+	struct sti_fps_info *fps;
+	int fpks, fipks, ms_since_last, num_frames, num_fields;
+
+	getrawmonotonic(&now);
+
+	/* Compute number of frame updates */
+	fps = &plane->fps_info;
+
+	if (new_field)
+		fps->curr_field_counter++;
+
+	/* do not perform fps calcul if new_frame is false */
+	if (!new_frame)
+		return;
+
+	fps->curr_frame_counter++;
+	ms_since_last = sti_plane_timespec_ms_diff(now, fps->last_timestamp);
+	num_frames = fps->curr_frame_counter - fps->last_frame_counter;
+
+	if (num_frames <= 0  || ms_since_last < STI_FPS_INTERVAL_MS)
+		return;
+
+	fps->last_timestamp = now;
+	fps->last_frame_counter = fps->curr_frame_counter;
+	fpks = (num_frames * 1000000) / ms_since_last;
+	snprintf(plane->fps_info.fps_str, FPS_LENGTH, "%-6s @ %d.%.3d fps",
+		 sti_plane_to_str(plane), fpks / 1000, fpks % 1000);
+
+	if (fps->curr_field_counter) {
+		/* Compute number of field updates */
+		num_fields = fps->curr_field_counter - fps->last_field_counter;
+		fps->last_field_counter = fps->curr_field_counter;
+		fipks = (num_fields * 1000000) / ms_since_last;
+		snprintf(plane->fps_info.fips_str,
+			 FPS_LENGTH, " - %d.%.3d field/sec",
+			 fipks / 1000, fipks % 1000);
+	} else {
+		plane->fps_info.fips_str[0] = '\0';
+	}
+
+	if (fps->output)
+		DRM_INFO("%s%s\n",
+			 plane->fps_info.fps_str,
+			 plane->fps_info.fips_str);
+}
+
 static void sti_plane_destroy(struct drm_plane *drm_plane)
 {
 	DRM_DEBUG_DRIVER("\n");