drm/vc4: crtc: Move the CRTC disable out

We'll need to reuse the part that disables the HVS and PixelValve during
boot too, so let's create a separate function.
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Tested-by: Chanwoo Choi <cw00.choi@samsung.com>
Tested-by: Hoegeun Kwon <hoegeun.kwon@samsung.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/5288fb72ed2da643085dce1bc7f6d6f656bf176e.1599120059.git-series.maxime@cerno.tech

drivers/gpu/drm/vc4/vc4_crtc.c

@@ -384,20 +384,14 @@ static void require_hvs_enabled(struct drm_device *dev)
 		     SCALER_DISPCTRL_ENABLE);
 }
 
-static void vc4_crtc_atomic_disable(struct drm_crtc *crtc,
-				    struct drm_crtc_state *old_state)
+static int vc4_crtc_disable(struct drm_crtc *crtc, unsigned int channel)
 {
-	struct drm_device *dev = crtc->dev;
-	struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);
 	struct drm_encoder *encoder = vc4_get_crtc_encoder(crtc);
 	struct vc4_encoder *vc4_encoder = to_vc4_encoder(encoder);
+	struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);
+	struct drm_device *dev = crtc->dev;
 	int ret;
 
-	require_hvs_enabled(dev);
-
-	/* Disable vblank irq handling before crtc is disabled. */
-	drm_crtc_vblank_off(crtc);
-
 	CRTC_WRITE(PV_V_CONTROL,
 		   CRTC_READ(PV_V_CONTROL) & ~PV_VCONTROL_VIDEN);
 	ret = wait_for(!(CRTC_READ(PV_V_CONTROL) & PV_VCONTROL_VIDEN), 1);
@@ -421,15 +415,31 @@ static void vc4_crtc_atomic_disable(struct drm_crtc *crtc,
 	 */
 	mdelay(20);
 
-	if (vc4_encoder->post_crtc_disable)
+	if (vc4_encoder && vc4_encoder->post_crtc_disable)
 		vc4_encoder->post_crtc_disable(encoder);
 
 	vc4_crtc_pixelvalve_reset(crtc);
-	vc4_hvs_atomic_disable(crtc, old_state);
+	vc4_hvs_stop_channel(dev, channel);
 
-	if (vc4_encoder->post_crtc_powerdown)
+	if (vc4_encoder && vc4_encoder->post_crtc_powerdown)
 		vc4_encoder->post_crtc_powerdown(encoder);
 
+	return 0;
+}
+
+static void vc4_crtc_atomic_disable(struct drm_crtc *crtc,
+				    struct drm_crtc_state *old_state)
+{
+	struct vc4_crtc_state *old_vc4_state = to_vc4_crtc_state(old_state);
+	struct drm_device *dev = crtc->dev;
+
+	require_hvs_enabled(dev);
+
+	/* Disable vblank irq handling before crtc is disabled. */
+	drm_crtc_vblank_off(crtc);
+
+	vc4_crtc_disable(crtc, old_vc4_state->assigned_channel);
+
 	/*
 	 * Make sure we issue a vblank event after disabling the CRTC if
 	 * someone was waiting it.