drm/sun4i: Fix layer zpos change/atomic modesetting

Identical configurations of planes can lead to different (and wrong)
layer -> pipe routing at HW level, depending on the order of atomic
plane changes.

For example:

- Layer 1 is configured to zpos 0 and thus uses pipe 0. No other layer
is enabled. This is a typical situation at boot.

- When a compositor takes over and layer 3 is enabled,
sun8i_ui_layer_enable() will get called with old_zpos=0 zpos=1, which
will lead to incorrect disabling of pipe 0 and enabling of pipe 1.

What happens is that sun8i_ui_layer_enable() function may disable
blender pipes even if it is no longer assigned to its layer.

To correct this, move the routing setup out of individual plane's
atomic_update into crtc's atomic_update, where it can be calculated
and updated all at once.

Remove the atomic_disable callback because it is no longer needed.

Signed-off-by: Ondrej Jirman <[e-mail]>
Reviewed-by: Jernej Skrabec <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Maxime Ripard <[e-mail]>

drivers/gpu/drm/sun4i/sun8i_mixer.c

···
 	return -EINVAL;
 }
 
+static void sun8i_layer_enable(struct sun8i_layer *layer, bool enable)
+{
+	u32 ch_base = sun8i_channel_base(layer->mixer, layer->channel);
+	u32 val, reg, mask;
+
+	if (layer->type == SUN8I_LAYER_TYPE_UI) {
+		val = enable ? SUN8I_MIXER_CHAN_UI_LAYER_ATTR_EN : 0;
+		mask = SUN8I_MIXER_CHAN_UI_LAYER_ATTR_EN;
+		reg = SUN8I_MIXER_CHAN_UI_LAYER_ATTR(ch_base, layer->overlay);
+	} else {
+		val = enable ? SUN8I_MIXER_CHAN_VI_LAYER_ATTR_EN : 0;
+		mask = SUN8I_MIXER_CHAN_VI_LAYER_ATTR_EN;
+		reg = SUN8I_MIXER_CHAN_VI_LAYER_ATTR(ch_base, layer->overlay);
+	}
+
+	regmap_update_bits(layer->mixer->engine.regs, reg, mask, val);
+}
+
 static void sun8i_mixer_commit(struct sunxi_engine *engine,
 			       struct drm_crtc *crtc,
 			       struct drm_atomic_state *state)
 {
+	struct sun8i_mixer *mixer = engine_to_sun8i_mixer(engine);
+	u32 bld_base = sun8i_blender_base(mixer);
+	struct drm_plane_state *plane_state;
+	struct drm_plane *plane;
+	u32 route = 0, pipe_en = 0;
+
 	DRM_DEBUG_DRIVER("Committing changes\n");
+
+	drm_for_each_plane(plane, state->dev) {
+		struct sun8i_layer *layer = plane_to_sun8i_layer(plane);
+		bool enable;
+		int zpos;
+
+		if (!(plane->possible_crtcs & drm_crtc_mask(crtc)) || layer->mixer != mixer)
+			continue;
+
+		plane_state = drm_atomic_get_new_plane_state(state, plane);
+		if (!plane_state)
+			plane_state = plane->state;
+
+		enable = plane_state->crtc && plane_state->visible;
+		zpos = plane_state->normalized_zpos;
+
+		DRM_DEBUG_DRIVER("  plane %d: chan=%d ovl=%d en=%d zpos=%d\n",
+				 plane->base.id, layer->channel, layer->overlay,
+				 enable, zpos);
+
+		/*
+		 * We always update the layer enable bit, because it can clear
+		 * spontaneously for unknown reasons.
+		 */
+		sun8i_layer_enable(layer, enable);
+
+		if (!enable)
+			continue;
+
+		/* Route layer to pipe based on zpos */
+		route |= layer->channel << SUN8I_MIXER_BLEND_ROUTE_PIPE_SHIFT(zpos);
+		pipe_en |= SUN8I_MIXER_BLEND_PIPE_CTL_EN(zpos);
+	}
+
+	regmap_write(mixer->engine.regs, SUN8I_MIXER_BLEND_ROUTE(bld_base), route);
+	regmap_write(mixer->engine.regs, SUN8I_MIXER_BLEND_PIPE_CTL(bld_base),
+		     pipe_en | SUN8I_MIXER_BLEND_PIPE_CTL_FC_EN(0));
 
 	regmap_write(engine->regs, SUN8I_MIXER_GLOBAL_DBUFF,
 		     SUN8I_MIXER_GLOBAL_DBUFF_ENABLE);

drivers/gpu/drm/sun4i/sun8i_mixer.h

···
 	struct clk			*mod_clk;
 };
 
+enum {
+	SUN8I_LAYER_TYPE_UI,
+	SUN8I_LAYER_TYPE_VI,
+};
+
 struct sun8i_layer {
 	struct drm_plane	plane;
 	struct sun8i_mixer	*mixer;
+	int			type;
 	int			channel;
 	int			overlay;
 };

drivers/gpu/drm/sun4i/sun8i_ui_layer.c

···
 #include "sun8i_ui_layer.h"
 #include "sun8i_ui_scaler.h"
 
-static void sun8i_ui_layer_enable(struct sun8i_mixer *mixer, int channel,
-				  int overlay, bool enable, unsigned int zpos,
-				  unsigned int old_zpos)
-{
-	u32 val, bld_base, ch_base;
-
-	bld_base = sun8i_blender_base(mixer);
-	ch_base = sun8i_channel_base(mixer, channel);
-
-	DRM_DEBUG_DRIVER("%sabling channel %d overlay %d\n",
-			 enable ? "En" : "Dis", channel, overlay);
-
-	if (enable)
-		val = SUN8I_MIXER_CHAN_UI_LAYER_ATTR_EN;
-	else
-		val = 0;
-
-	regmap_update_bits(mixer->engine.regs,
-			   SUN8I_MIXER_CHAN_UI_LAYER_ATTR(ch_base, overlay),
-			   SUN8I_MIXER_CHAN_UI_LAYER_ATTR_EN, val);
-
-	if (!enable || zpos != old_zpos) {
-		regmap_update_bits(mixer->engine.regs,
-				   SUN8I_MIXER_BLEND_PIPE_CTL(bld_base),
-				   SUN8I_MIXER_BLEND_PIPE_CTL_EN(old_zpos),
-				   0);
-
-		regmap_update_bits(mixer->engine.regs,
-				   SUN8I_MIXER_BLEND_ROUTE(bld_base),
-				   SUN8I_MIXER_BLEND_ROUTE_PIPE_MSK(old_zpos),
-				   0);
-	}
-
-	if (enable) {
-		val = SUN8I_MIXER_BLEND_PIPE_CTL_EN(zpos);
-
-		regmap_update_bits(mixer->engine.regs,
-				   SUN8I_MIXER_BLEND_PIPE_CTL(bld_base),
-				   val, val);
-
-		val = channel << SUN8I_MIXER_BLEND_ROUTE_PIPE_SHIFT(zpos);
-
-		regmap_update_bits(mixer->engine.regs,
-				   SUN8I_MIXER_BLEND_ROUTE(bld_base),
-				   SUN8I_MIXER_BLEND_ROUTE_PIPE_MSK(zpos),
-				   val);
-	}
-}
-
 static void sun8i_ui_layer_update_alpha(struct sun8i_mixer *mixer, int channel,
 					int overlay, struct drm_plane *plane)
 {
···
 						   true, true);
 }
 
-static void sun8i_ui_layer_atomic_disable(struct drm_plane *plane,
-					  struct drm_atomic_state *state)
-{
-	struct drm_plane_state *old_state = drm_atomic_get_old_plane_state(state,
-									   plane);
-	struct sun8i_layer *layer = plane_to_sun8i_layer(plane);
-	unsigned int old_zpos = old_state->normalized_zpos;
-	struct sun8i_mixer *mixer = layer->mixer;
-
-	sun8i_ui_layer_enable(mixer, layer->channel, layer->overlay, false, 0,
-			      old_zpos);
-}
 
 static void sun8i_ui_layer_atomic_update(struct drm_plane *plane,
 					 struct drm_atomic_state *state)
 {
-	struct drm_plane_state *old_state = drm_atomic_get_old_plane_state(state,
-									   plane);
 	struct drm_plane_state *new_state = drm_atomic_get_new_plane_state(state,
 									   plane);
 	struct sun8i_layer *layer = plane_to_sun8i_layer(plane);
 	unsigned int zpos = new_state->normalized_zpos;
-	unsigned int old_zpos = old_state->normalized_zpos;
 	struct sun8i_mixer *mixer = layer->mixer;
 
-	if (!new_state->visible) {
-		sun8i_ui_layer_enable(mixer, layer->channel,
-				      layer->overlay, false, 0, old_zpos);
+	if (!new_state->crtc || !new_state->visible)
 		return;
-	}
 
 	sun8i_ui_layer_update_coord(mixer, layer->channel,
 				    layer->overlay, plane, zpos);
···
 				      layer->overlay, plane);
 	sun8i_ui_layer_update_buffer(mixer, layer->channel,
 				     layer->overlay, plane);
-	sun8i_ui_layer_enable(mixer, layer->channel, layer->overlay,
-			      true, zpos, old_zpos);
 }
 
 static const struct drm_plane_helper_funcs sun8i_ui_layer_helper_funcs = {
 	.atomic_check	= sun8i_ui_layer_atomic_check,
-	.atomic_disable	= sun8i_ui_layer_atomic_disable,
 	.atomic_update	= sun8i_ui_layer_atomic_update,
 };
 
···
 
 	drm_plane_helper_add(&layer->plane, &sun8i_ui_layer_helper_funcs);
 	layer->mixer = mixer;
+	layer->type = SUN8I_LAYER_TYPE_UI;
 	layer->channel = channel;
 	layer->overlay = 0;
 

drivers/gpu/drm/sun4i/sun8i_vi_layer.c

···
 #include "sun8i_vi_layer.h"
 #include "sun8i_vi_scaler.h"
 
-static void sun8i_vi_layer_enable(struct sun8i_mixer *mixer, int channel,
-				  int overlay, bool enable, unsigned int zpos,
-				  unsigned int old_zpos)
-{
-	u32 val, bld_base, ch_base;
-
-	bld_base = sun8i_blender_base(mixer);
-	ch_base = sun8i_channel_base(mixer, channel);
-
-	DRM_DEBUG_DRIVER("%sabling VI channel %d overlay %d\n",
-			 enable ? "En" : "Dis", channel, overlay);
-
-	if (enable)
-		val = SUN8I_MIXER_CHAN_VI_LAYER_ATTR_EN;
-	else
-		val = 0;
-
-	regmap_update_bits(mixer->engine.regs,
-			   SUN8I_MIXER_CHAN_VI_LAYER_ATTR(ch_base, overlay),
-			   SUN8I_MIXER_CHAN_VI_LAYER_ATTR_EN, val);
-
-	if (!enable || zpos != old_zpos) {
-		regmap_update_bits(mixer->engine.regs,
-				   SUN8I_MIXER_BLEND_PIPE_CTL(bld_base),
-				   SUN8I_MIXER_BLEND_PIPE_CTL_EN(old_zpos),
-				   0);
-
-		regmap_update_bits(mixer->engine.regs,
-				   SUN8I_MIXER_BLEND_ROUTE(bld_base),
-				   SUN8I_MIXER_BLEND_ROUTE_PIPE_MSK(old_zpos),
-				   0);
-	}
-
-	if (enable) {
-		val = SUN8I_MIXER_BLEND_PIPE_CTL_EN(zpos);
-
-		regmap_update_bits(mixer->engine.regs,
-				   SUN8I_MIXER_BLEND_PIPE_CTL(bld_base),
-				   val, val);
-
-		val = channel << SUN8I_MIXER_BLEND_ROUTE_PIPE_SHIFT(zpos);
-
-		regmap_update_bits(mixer->engine.regs,
-				   SUN8I_MIXER_BLEND_ROUTE(bld_base),
-				   SUN8I_MIXER_BLEND_ROUTE_PIPE_MSK(zpos),
-				   val);
-	}
-}
-
 static void sun8i_vi_layer_update_alpha(struct sun8i_mixer *mixer, int channel,
 					int overlay, struct drm_plane *plane)
 {
···
 						   true, true);
 }
 
-static void sun8i_vi_layer_atomic_disable(struct drm_plane *plane,
-					  struct drm_atomic_state *state)
-{
-	struct drm_plane_state *old_state = drm_atomic_get_old_plane_state(state,
-									   plane);
-	struct sun8i_layer *layer = plane_to_sun8i_vi_layer(plane);
-	unsigned int old_zpos = old_state->normalized_zpos;
-	struct sun8i_mixer *mixer = layer->mixer;
-
-	sun8i_vi_layer_enable(mixer, layer->channel, layer->overlay, false, 0,
-			      old_zpos);
-}
-
 static void sun8i_vi_layer_atomic_update(struct drm_plane *plane,
 					 struct drm_atomic_state *state)
 {
-	struct drm_plane_state *old_state = drm_atomic_get_old_plane_state(state,
-									   plane);
 	struct drm_plane_state *new_state = drm_atomic_get_new_plane_state(state,
 									   plane);
 	struct sun8i_layer *layer = plane_to_sun8i_layer(plane);
 	unsigned int zpos = new_state->normalized_zpos;
-	unsigned int old_zpos = old_state->normalized_zpos;
 	struct sun8i_mixer *mixer = layer->mixer;
 
-	if (!new_state->visible) {
-		sun8i_vi_layer_enable(mixer, layer->channel,
-				      layer->overlay, false, 0, old_zpos);
+	if (!new_state->crtc || !new_state->visible)
 		return;
-	}
 
 	sun8i_vi_layer_update_coord(mixer, layer->channel,
 				    layer->overlay, plane, zpos);
···
 				      layer->overlay, plane);
 	sun8i_vi_layer_update_buffer(mixer, layer->channel,
 				     layer->overlay, plane);
-	sun8i_vi_layer_enable(mixer, layer->channel, layer->overlay,
-			      true, zpos, old_zpos);
 }
 
 static const struct drm_plane_helper_funcs sun8i_vi_layer_helper_funcs = {
 	.atomic_check	= sun8i_vi_layer_atomic_check,
-	.atomic_disable	= sun8i_vi_layer_atomic_disable,
 	.atomic_update	= sun8i_vi_layer_atomic_update,
 };
 
···
 
 	drm_plane_helper_add(&layer->plane, &sun8i_vi_layer_helper_funcs);
 	layer->mixer = mixer;
+	layer->type = SUN8I_LAYER_TYPE_VI;
 	layer->channel = index;
 	layer->overlay = 0;