drm/tilcdc: Turn raster off in crtc reset, if it was on in the HW

This forces the HW to be in sync with the empty state. This should
help with the problem when LCDC is already enabled (e.g. by the
bootloader) at the initialization phase and the enable fails when a
new mode is applied.
Signed-off-by: Jyri Sarha <jsarha@ti.com>

drivers/gpu/drm/tilcdc/tilcdc_crtc.c

@@ -728,11 +728,39 @@ static void tilcdc_crtc_disable_vblank(struct drm_crtc *crtc)
 {
 }
 
+static void tilcdc_crtc_reset(struct drm_crtc *crtc)
+{
+	struct tilcdc_crtc *tilcdc_crtc = to_tilcdc_crtc(crtc);
+	struct drm_device *dev = crtc->dev;
+	int ret;
+
+	drm_atomic_helper_crtc_reset(crtc);
+
+	/* Turn the raster off if it for some reason is on. */
+	pm_runtime_get_sync(dev->dev);
+	if (tilcdc_read(dev, LCDC_RASTER_CTRL_REG) & LCDC_RASTER_ENABLE) {
+		/* Enable DMA Frame Done Interrupt */
+		tilcdc_write(dev, LCDC_INT_ENABLE_SET_REG, LCDC_FRAME_DONE);
+		tilcdc_clear_irqstatus(dev, 0xffffffff);
+
+		tilcdc_crtc->frame_done = false;
+		tilcdc_clear(dev, LCDC_RASTER_CTRL_REG, LCDC_RASTER_ENABLE);
+
+		ret = wait_event_timeout(tilcdc_crtc->frame_done_wq,
+					 tilcdc_crtc->frame_done,
+					 msecs_to_jiffies(500));
+		if (ret == 0)
+			dev_err(dev->dev, "%s: timeout waiting for framedone\n",
+				__func__);
+	}
+	pm_runtime_put_sync(dev->dev);
+}
+
 static const struct drm_crtc_funcs tilcdc_crtc_funcs = {
 	.destroy        = tilcdc_crtc_destroy,
 	.set_config     = drm_atomic_helper_set_config,
 	.page_flip      = drm_atomic_helper_page_flip,
-	.reset		= drm_atomic_helper_crtc_reset,
+	.reset		= tilcdc_crtc_reset,
 	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
 	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
 	.enable_vblank	= tilcdc_crtc_enable_vblank,