diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
index 554c2e29b23d..860be019d8e3 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -908,6 +908,7 @@ void vc4_irq_reset(struct drm_device *dev);
 /* vc4_hvs.c */
 extern struct platform_driver vc4_hvs_driver;
 void vc4_hvs_stop_channel(struct drm_device *dev, unsigned int output);
+int vc4_hvs_get_fifo_from_output(struct drm_device *dev, unsigned int output);
 int vc4_hvs_atomic_check(struct drm_crtc *crtc, struct drm_crtc_state *state);
 void vc4_hvs_atomic_enable(struct drm_crtc *crtc, struct drm_crtc_state *old_state);
 void vc4_hvs_atomic_disable(struct drm_crtc *crtc, struct drm_crtc_state *old_state);
diff --git a/drivers/gpu/drm/vc4/vc4_hvs.c b/drivers/gpu/drm/vc4/vc4_hvs.c
index b5ee9556e821..4d0a833366ce 100644
--- a/drivers/gpu/drm/vc4/vc4_hvs.c
+++ b/drivers/gpu/drm/vc4/vc4_hvs.c
@@ -19,6 +19,7 @@
  * each CRTC.
  */
 
+#include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/component.h>
 #include <linux/platform_device.h>
@@ -196,6 +197,59 @@ static void vc4_hvs_update_gamma_lut(struct drm_crtc *crtc)
 	vc4_hvs_lut_load(crtc);
 }
 
+int vc4_hvs_get_fifo_from_output(struct drm_device *dev, unsigned int output)
+{
+	struct vc4_dev *vc4 = to_vc4_dev(dev);
+	u32 reg;
+	int ret;
+
+	if (!vc4->hvs->hvs5)
+		return output;
+
+	switch (output) {
+	case 0:
+		return 0;
+
+	case 1:
+		return 1;
+
+	case 2:
+		reg = HVS_READ(SCALER_DISPECTRL);
+		ret = FIELD_GET(SCALER_DISPECTRL_DSP2_MUX_MASK, reg);
+		if (ret == 0)
+			return 2;
+
+		return 0;
+
+	case 3:
+		reg = HVS_READ(SCALER_DISPCTRL);
+		ret = FIELD_GET(SCALER_DISPCTRL_DSP3_MUX_MASK, reg);
+		if (ret == 3)
+			return -EPIPE;
+
+		return ret;
+
+	case 4:
+		reg = HVS_READ(SCALER_DISPEOLN);
+		ret = FIELD_GET(SCALER_DISPEOLN_DSP4_MUX_MASK, reg);
+		if (ret == 3)
+			return -EPIPE;
+
+		return ret;
+
+	case 5:
+		reg = HVS_READ(SCALER_DISPDITHER);
+		ret = FIELD_GET(SCALER_DISPDITHER_DSP5_MUX_MASK, reg);
+		if (ret == 3)
+			return -EPIPE;
+
+		return ret;
+
+	default:
+		return -EPIPE;
+	}
+}
+
 static int vc4_hvs_init_channel(struct vc4_dev *vc4, struct drm_crtc *crtc,
 				struct drm_display_mode *mode, bool oneshot)
 {