drm/stm: ltdc: add user update info in plane print state

This patch adds the user update information in
frames-per-second into the drm debugfs plane state.
Signed-off-by: Philippe Cornu <philippe.cornu@st.com>
Reviewed-by: Vincent Abriou <vincent.abriou@st.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180407213503.30932-1-philippe.cornu@st.com

drivers/gpu/drm/stm/ltdc.c

@@ -729,6 +729,8 @@ static void ltdc_plane_atomic_update(struct drm_plane *plane,
 	reg_update_bits(ldev->regs, LTDC_L1CR + lofs,
 			LXCR_LEN | LXCR_CLUTEN, val);
 
+	ldev->plane_fpsi[plane->index].counter++;
+
 	mutex_lock(&ldev->err_lock);
 	if (ldev->error_status & ISR_FUIF) {
 		DRM_DEBUG_DRIVER("Fifo underrun\n");
@@ -754,6 +756,25 @@ static void ltdc_plane_atomic_disable(struct drm_plane *plane,
 			 oldstate->crtc->base.id, plane->base.id);
 }
 
+static void ltdc_plane_atomic_print_state(struct drm_printer *p,
+					  const struct drm_plane_state *state)
+{
+	struct drm_plane *plane = state->plane;
+	struct ltdc_device *ldev = plane_to_ltdc(plane);
+	struct fps_info *fpsi = &ldev->plane_fpsi[plane->index];
+	int ms_since_last;
+	ktime_t now;
+
+	now = ktime_get();
+	ms_since_last = ktime_to_ms(ktime_sub(now, fpsi->last_timestamp));
+
+	drm_printf(p, "\tuser_updates=%dfps\n",
+		   DIV_ROUND_CLOSEST(fpsi->counter * 1000, ms_since_last));
+
+	fpsi->last_timestamp = now;
+	fpsi->counter = 0;
+}
+
 static const struct drm_plane_funcs ltdc_plane_funcs = {
 	.update_plane = drm_atomic_helper_update_plane,
 	.disable_plane = drm_atomic_helper_disable_plane,
@@ -761,6 +782,7 @@ static const struct drm_plane_funcs ltdc_plane_funcs = {
 	.reset = drm_atomic_helper_plane_reset,
 	.atomic_duplicate_state = drm_atomic_helper_plane_duplicate_state,
 	.atomic_destroy_state = drm_atomic_helper_plane_destroy_state,
+	.atomic_print_state = ltdc_plane_atomic_print_state,
 };
 
 static const struct drm_plane_helper_funcs ltdc_plane_helper_funcs = {

drivers/gpu/drm/stm/ltdc.h

@@ -20,6 +20,13 @@ struct ltdc_caps {
 	bool non_alpha_only_l1; /* non-native no-alpha formats on layer 1 */
 };
 
+#define LTDC_MAX_LAYER	4
+
+struct fps_info {
+	unsigned int counter;
+	ktime_t last_timestamp;
+};
+
 struct ltdc_device {
 	void __iomem *regs;
 	struct clk *pixel_clk;	/* lcd pixel clock */
@@ -27,6 +34,7 @@ struct ltdc_device {
 	struct ltdc_caps caps;
 	u32 error_status;
 	u32 irq_status;
+	struct fps_info plane_fpsi[LTDC_MAX_LAYER];
 };
 
 int ltdc_load(struct drm_device *ddev);