[PATCH RFT 2/2] drm/vc4: hvs: Clear the HVS list at boot

[Maxime Ripard]

The kernel boots with the display running and we make sure to shut down
the scan out engines properly but we keep the display list for now.
Let's make sure we start from a clean state.

Signed-off-by: Maxime Ripard <maxime at cerno.tech>
---
 drivers/gpu/drm/vc4/vc4_drv.c |  1 +
 drivers/gpu/drm/vc4/vc4_drv.h |  1 +
 drivers/gpu/drm/vc4/vc4_hvs.c | 12 ++++++++++++
 3 files changed, 14 insertions(+)

diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
index 2cd97a39c286..9fbf03872b24 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.c
+++ b/drivers/gpu/drm/vc4/vc4_drv.c
@@ -289,6 +289,7 @@ static int vc4_drm_bind(struct device *dev)
 
 	drm_for_each_crtc(crtc, drm)
 		vc4_crtc_disable_at_boot(crtc);
+	vc4_hvs_clear_dlist(drm);
 
 	ret = drm_dev_register(drm, 0);
 	if (ret < 0)
diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
index 051ad4e31e52..493a85c4d11a 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -911,6 +911,7 @@ void vc4_irq_reset(struct drm_device *dev);
 
 /* vc4_hvs.c */
 extern struct platform_driver vc4_hvs_driver;
+void vc4_hvs_clear_dlist(struct drm_device *dev);
 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_atomic_state *state);
diff --git a/drivers/gpu/drm/vc4/vc4_hvs.c b/drivers/gpu/drm/vc4/vc4_hvs.c
index 2b3a597fa65f..1fe40f3cbcfb 100644
--- a/drivers/gpu/drm/vc4/vc4_hvs.c
+++ b/drivers/gpu/drm/vc4/vc4_hvs.c
@@ -326,6 +326,18 @@ void vc4_hvs_stop_channel(struct drm_device *dev, unsigned int chan)
 		     SCALER_DISPSTATX_EMPTY);
 }
 
+void vc4_hvs_clear_dlist(struct drm_device *dev)
+{
+	struct vc4_dev *vc4 = to_vc4_dev(dev);
+	void __iomem *dlist_start = vc4->hvs->dlist;
+	unsigned int i;
+
+	for (i = 0; i < 0x4000; i += 4)
+		writel(SCALER_CTL0_END, dlist_start + i);
+
+	vc4_hvs_dump_state(dev);
+}
+
 int vc4_hvs_atomic_check(struct drm_crtc *crtc, struct drm_atomic_state *state)
 {
 	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
-- 
2.29.2