drm/imx: add deferred plane disabling

commit eb8c88808c8307b05ce42e101753cb2518c6d14e upstream.

The DP (display processor) channel disable code tried to busy wait for
the DP sync flow end interrupt status bit when disabling the partial
plane without a full modeset. That never worked reliably, and it was
disabled completely by the recent "gpu: ipu-v3: remove IRQ dance on DC
channel disable" patch, causing ipu_wait_interrupt to always time out
after 50 ms, which in turn would trigger a timeout in
drm_atomic_helper_wait_for_vblanks.

This patch changes ipu_plane_atomic_disable to only queue a DP channel
register update at the next frame boundary and set a flag, which can be
done without any waiting whatsoever. The imx_drm_atomic_commit_tail then
calls a new ipu_plane_disable_deferred function that does the actual
IDMAC teardown of the planes that are flagged for deferred disabling,
after waiting for the vblank.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>

5 files changed, 62 insertions, 11 deletions

diff --git a/drivers/gpu/drm/imx/imx-drm-core.c b/drivers/gpu/drm/imx/imx-drm-core.c
index 13a5a2587a1e..a11846be980e 100644
--- a/drivers/gpu/drm/imx/imx-drm-core.c
+++ b/drivers/gpu/drm/imx/imx-drm-core.c
@@ -30,6 +30,7 @@
 #include <video/imx-ipu-v3.h>
 
 #include "imx-drm.h"
+#include "ipuv3-plane.h"
 
 #define MAX_CRTC	4
 
@@ -160,6 +161,10 @@ static const struct drm_mode_config_funcs imx_drm_mode_config_funcs = {
 static void imx_drm_atomic_commit_tail(struct drm_atomic_state *state)
 {
 	struct drm_device *dev = state->dev;
+	struct drm_plane *plane;
+	struct drm_plane_state *old_plane_state;
+	bool plane_disabling = false;
+	int i;
 
 	drm_atomic_helper_commit_modeset_disables(dev, state);
 
@@ -169,6 +174,19 @@ static void imx_drm_atomic_commit_tail(struct drm_atomic_state *state)
 
 	drm_atomic_helper_commit_modeset_enables(dev, state);
 
+	for_each_plane_in_state(state, plane, old_plane_state, i) {
+		if (drm_atomic_plane_disabling(plane, old_plane_state))
+			plane_disabling = true;
+	}
+
+	if (plane_disabling) {
+		drm_atomic_helper_wait_for_vblanks(dev, state);
+
+		for_each_plane_in_state(state, plane, old_plane_state, i)
+			ipu_plane_disable_deferred(plane);
+
+	}
+
 	drm_atomic_helper_commit_hw_done(state);
 }
 
diff --git a/drivers/gpu/drm/imx/ipuv3-crtc.c b/drivers/gpu/drm/imx/ipuv3-crtc.c
index 6be515a9fb69..0f15f11f26e0 100644
--- a/drivers/gpu/drm/imx/ipuv3-crtc.c
+++ b/drivers/gpu/drm/imx/ipuv3-crtc.c
@@ -60,6 +60,26 @@ static void ipu_crtc_enable(struct drm_crtc *crtc)
 	ipu_di_enable(ipu_crtc->di);
 }
 
+static void ipu_crtc_disable_planes(struct ipu_crtc *ipu_crtc,
+				    struct drm_crtc_state *old_crtc_state)
+{
+	bool disable_partial = false;
+	bool disable_full = false;
+	struct drm_plane *plane;
+
+	drm_atomic_crtc_state_for_each_plane(plane, old_crtc_state) {
+		if (plane == &ipu_crtc->plane[0]->base)
+			disable_full = true;
+		if (&ipu_crtc->plane[1] && plane == &ipu_crtc->plane[1]->base)
+			disable_partial = true;
+	}
+
+	if (disable_partial)
+		ipu_plane_disable(ipu_crtc->plane[1], true);
+	if (disable_full)
+		ipu_plane_disable(ipu_crtc->plane[0], false);
+}
+
 static void ipu_crtc_atomic_disable(struct drm_crtc *crtc,
 				    struct drm_crtc_state *old_crtc_state)
 {
@@ -73,7 +93,7 @@ static void ipu_crtc_atomic_disable(struct drm_crtc *crtc,
 	 * attached IDMACs will be left in undefined state, possibly hanging
 	 * the IPU or even system.
 	 */
-	drm_atomic_helper_disable_planes_on_crtc(old_crtc_state, false);
+	ipu_crtc_disable_planes(ipu_crtc, old_crtc_state);
 	ipu_dc_disable(ipu);
 
 	spin_lock_irq(&crtc->dev->event_lock);
diff --git a/drivers/gpu/drm/imx/ipuv3-plane.c b/drivers/gpu/drm/imx/ipuv3-plane.c
index deb0c786137b..24a74a327bba 100644
--- a/drivers/gpu/drm/imx/ipuv3-plane.c
+++ b/drivers/gpu/drm/imx/ipuv3-plane.c
@@ -172,23 +172,30 @@ static void ipu_plane_enable(struct ipu_plane *ipu_plane)
 		ipu_dp_enable_channel(ipu_plane->dp);
 }
 
-static int ipu_disable_plane(struct drm_plane *plane)
+void ipu_plane_disable(struct ipu_plane *ipu_plane, bool disable_dp_channel)
 {
-	struct ipu_plane *ipu_plane = to_ipu_plane(plane);
-
 	DRM_DEBUG_KMS("[%d] %s\n", __LINE__, __func__);
 
 	ipu_idmac_wait_busy(ipu_plane->ipu_ch, 50);
 
-	if (ipu_plane->dp)
-		ipu_dp_disable_channel(ipu_plane->dp, true);
+	if (ipu_plane->dp && disable_dp_channel)
+		ipu_dp_disable_channel(ipu_plane->dp, false);
 	ipu_idmac_disable_channel(ipu_plane->ipu_ch);
 	ipu_dmfc_disable_channel(ipu_plane->dmfc);
 	if (ipu_plane->dp)
 		ipu_dp_disable(ipu_plane->ipu);
+}
 
-	return 0;
+void ipu_plane_disable_deferred(struct drm_plane *plane)
+{
+	struct ipu_plane *ipu_plane = to_ipu_plane(plane);
+
+	if (ipu_plane->disabling) {
+		ipu_plane->disabling = false;
+		ipu_plane_disable(ipu_plane, false);
+	}
 }
+EXPORT_SYMBOL_GPL(ipu_plane_disable_deferred);
 
 static void ipu_plane_destroy(struct drm_plane *plane)
 {
@@ -361,7 +368,11 @@ static int ipu_plane_atomic_check(struct drm_plane *plane,
 static void ipu_plane_atomic_disable(struct drm_plane *plane,
 				     struct drm_plane_state *old_state)
 {
-	ipu_disable_plane(plane);
+	struct ipu_plane *ipu_plane = to_ipu_plane(plane);
+
+	if (ipu_plane->dp)
+		ipu_dp_disable_channel(ipu_plane->dp, true);
+	ipu_plane->disabling = true;
 }
 
 static void ipu_plane_atomic_update(struct drm_plane *plane,
diff --git a/drivers/gpu/drm/imx/ipuv3-plane.h b/drivers/gpu/drm/imx/ipuv3-plane.h
index 338b88a74eb6..0e2a723ff981 100644
--- a/drivers/gpu/drm/imx/ipuv3-plane.h
+++ b/drivers/gpu/drm/imx/ipuv3-plane.h
@@ -23,6 +23,8 @@ struct ipu_plane {
 
 	int			dma;
 	int			dp_flow;
+
+	bool			disabling;
 };
 
 struct ipu_plane *ipu_plane_init(struct drm_device *dev, struct ipu_soc *ipu,
@@ -42,4 +44,7 @@ void ipu_plane_put_resources(struct ipu_plane *plane);
 
 int ipu_plane_irq(struct ipu_plane *plane);
 
+void ipu_plane_disable(struct ipu_plane *ipu_plane, bool disable_dp_channel);
+void ipu_plane_disable_deferred(struct drm_plane *plane);
+
 #endif
diff --git a/drivers/gpu/ipu-v3/ipu-dp.c b/drivers/gpu/ipu-v3/ipu-dp.c
index 0e09c98248a0..9b2b3fa479c4 100644
--- a/drivers/gpu/ipu-v3/ipu-dp.c
+++ b/drivers/gpu/ipu-v3/ipu-dp.c
@@ -277,9 +277,6 @@ void ipu_dp_disable_channel(struct ipu_dp *dp, bool sync)
 	writel(0, flow->base + DP_FG_POS);
 	ipu_srm_dp_update(priv->ipu, sync);
 
-	if (ipu_idmac_channel_busy(priv->ipu, IPUV3_CHANNEL_MEM_BG_SYNC))
-		ipu_wait_interrupt(priv->ipu, IPU_IRQ_DP_SF_END, 50);
-
 	mutex_unlock(&priv->mutex);
 }
 EXPORT_SYMBOL_GPL(ipu_dp_disable_channel);