[v4,09/10] drm: rcar-du: Perform group setup from the atomic tail handler

diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
index 7ca721e6b9d7..020eb75732a7 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
@@ -528,12 +528,10 @@  static int rcar_du_crtc_exit_standby(struct rcar_du_crtc *rcrtc)
 		return ret;
 
 	ret = clk_prepare_enable(rcrtc->extclock);
-	if (ret < 0)
-		goto error_clock;
-
-	ret = rcar_du_group_get(rcrtc->group);
-	if (ret < 0)
-		goto error_group;
+	if (ret < 0) {
+		clk_disable_unprepare(rcrtc->clock);
+		return ret;
+	}
 
 	/* Set display off and background to black. */
 	rcar_du_crtc_write(rcrtc, DOOR, DOOR_RGB(0, 0, 0));
@@ -543,18 +541,10 @@  static int rcar_du_crtc_exit_standby(struct rcar_du_crtc *rcrtc)
 	rcar_du_group_write(rcrtc->group, rcrtc->index % 2 ? DS2PR : DS1PR, 0);
 
 	return 0;
-
-error_group:
-	clk_disable_unprepare(rcrtc->extclock);
-error_clock:
-	clk_disable_unprepare(rcrtc->clock);
-	return ret;
 }
 
 static void rcar_du_crtc_enter_standby(struct rcar_du_crtc *rcrtc)
 {
-	rcar_du_group_put(rcrtc->group);
-
 	clk_disable_unprepare(rcrtc->extclock);
 	clk_disable_unprepare(rcrtc->clock);
 }
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_group.c b/drivers/gpu/drm/rcar-du/rcar_du_group.c
index 7c13def703b7..fdd4a60f5f5e 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_group.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_group.c
@@ -24,6 +24,7 @@ 
  */
 
 #include <linux/clk.h>
+#include <linux/err.h>
 #include <linux/io.h>
 #include <linux/slab.h>
 
@@ -183,38 +184,6 @@  static void rcar_du_group_setup(struct rcar_du_group *rgrp)
 	mutex_unlock(&rgrp->lock);
 }
 
-/*
- * rcar_du_group_get - Acquire a reference to the DU channels group
- *
- * Acquiring the first reference setups core registers. A reference must be held
- * before accessing any hardware registers.
- *
- * This function must be called with the DRM mode_config lock held.
- *
- * Return 0 in case of success or a negative error code otherwise.
- */
-int rcar_du_group_get(struct rcar_du_group *rgrp)
-{
-	if (rgrp->use_count)
-		goto done;
-
-	rcar_du_group_setup(rgrp);
-
-done:
-	rgrp->use_count++;
-	return 0;
-}
-
-/*
- * rcar_du_group_put - Release a reference to the DU
- *
- * This function must be called with the DRM mode_config lock held.
- */
-void rcar_du_group_put(struct rcar_du_group *rgrp)
-{
-	--rgrp->use_count;
-}
-
 static void __rcar_du_group_start_stop(struct rcar_du_group *rgrp, bool start)
 {
 	struct rcar_du_device *rcdu = rgrp->dev;
@@ -399,6 +368,34 @@  static const struct drm_private_state_funcs rcar_du_group_state_funcs = {
 	.atomic_destroy_state = rcar_du_group_atomic_destroy_state,
 };
 
+/**
+ * for_each_oldnew_group_in_state - iterate over all groups in an atomic update
+ * @__state: &struct drm_atomic_state pointer
+ * @__obj: &struct drm_private_obj iteration cursor
+ * @__old: &struct drm_private_state iteration cursor for the old state
+ * @__new: &struct drm_private_state iteration cursor for the new state
+ * @__i: unsigned int iteration cursor, for macro-internal use
+ *
+ * Iterate over all private objects in an atomic update, processing only those
+ * which represent rcar_du_group_state, tracking both old and new state.
+ */
+#define for_each_oldnew_group_in_state(__state, __obj, __old, __new, __i) \
+	for_each_oldnew_private_obj_in_state((__state), (__obj), (__old), (__new), (__i)) \
+		for_each_if((__obj)->funcs == &rcar_du_group_state_funcs)
+
+static struct rcar_du_group_state *
+rcar_du_get_group_state(struct drm_atomic_state *state,
+			struct rcar_du_group *rgrp)
+{
+	struct drm_private_state *pstate;
+
+	pstate = drm_atomic_get_private_obj_state(state, &rgrp->private);
+	if (IS_ERR(pstate))
+		return ERR_CAST(pstate);
+
+	return to_rcar_group_state(pstate);
+}
+
 /**
  * rcar_du_get_old_group_state - get old group state, if it exists
  * @state: global atomic state object
@@ -451,6 +448,47 @@  rcar_du_get_new_group_state(struct drm_atomic_state *state,
 	return NULL;
 }
 
+int rcar_du_group_atomic_check(struct drm_device *dev,
+			       struct drm_atomic_state *state)
+{
+	struct drm_crtc_state *crtc_state;
+	struct drm_crtc *crtc;
+	unsigned int i;
+
+	for_each_new_crtc_in_state(state, crtc, crtc_state, i) {
+		struct rcar_du_crtc *rcrtc = to_rcar_crtc(crtc);
+		struct rcar_du_group_state *gstate;
+
+		gstate = rcar_du_get_group_state(state, rcrtc->group);
+		if (IS_ERR(gstate))
+			return PTR_ERR(gstate);
+
+		if (crtc_state->active)
+			gstate->enabled = true;
+	}
+
+	return 0;
+}
+
+void rcar_du_group_atomic_setup(struct drm_device *dev,
+				struct drm_atomic_state *state)
+{
+	struct drm_private_state *old_pstate, *new_pstate;
+	struct drm_private_obj *obj;
+	unsigned int i;
+
+	for_each_oldnew_group_in_state(state, obj, old_pstate, new_pstate, i) {
+		struct rcar_du_group *rgrp = to_rcar_group(obj);
+		struct rcar_du_group_state *old_state, *new_state;
+
+		old_state = to_rcar_group_state(old_pstate);
+		new_state = to_rcar_group_state(new_pstate);
+
+		if (!old_state->enabled && new_state->enabled)
+			rcar_du_group_setup(rgrp);
+	}
+}
+
 /* -----------------------------------------------------------------------------
  * Init and Cleanup
  */
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_group.h b/drivers/gpu/drm/rcar-du/rcar_du_group.h
index f0b94eb77746..c6e0ae79ede9 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_group.h
+++ b/drivers/gpu/drm/rcar-du/rcar_du_group.h
@@ -27,7 +27,6 @@  struct rcar_du_device;
  * @channels_mask: bitmask of populated DU channels in this group
  * @cmms_mask: bitmask of available CMMs in this group
  * @num_crtcs: number of CRTCs in this group (1 or 2)
- * @use_count: number of users of the group (rcar_du_group_(get|put))
  * @used_crtcs: number of CRTCs currently in use
  * @lock: protects the dptsr_planes field and the DPTSR register
  * @dptsr_planes: bitmask of planes driven by dot-clock and timing generator 1
@@ -45,7 +44,6 @@  struct rcar_du_group {
 	unsigned int channels_mask;
 	unsigned int cmms_mask;
 	unsigned int num_crtcs;
-	unsigned int use_count;
 	unsigned int used_crtcs;
 
 	struct mutex lock;
@@ -61,9 +59,12 @@  struct rcar_du_group {
 /**
  * struct rcar_du_group_state - Driver-specific group state
  * @state: base DRM private state
+ * @enabled: true if at least one CRTC in the group is enabled
  */
 struct rcar_du_group_state {
 	struct drm_private_state state;
+
+	bool enabled;
 };
 
 #define to_rcar_group_state(s) \
@@ -72,8 +73,6 @@  struct rcar_du_group_state {
 u32 rcar_du_group_read(struct rcar_du_group *rgrp, u32 reg);
 void rcar_du_group_write(struct rcar_du_group *rgrp, u32 reg, u32 data);
 
-int rcar_du_group_get(struct rcar_du_group *rgrp);
-void rcar_du_group_put(struct rcar_du_group *rgrp);
 void rcar_du_group_start_stop(struct rcar_du_group *rgrp, bool start);
 void rcar_du_group_restart(struct rcar_du_group *rgrp);
 int rcar_du_group_set_routing(struct rcar_du_group *rgrp);
@@ -87,6 +86,11 @@  struct rcar_du_group_state *
 rcar_du_get_new_group_state(struct drm_atomic_state *state,
 			    struct rcar_du_group *rgrp);
 
+int rcar_du_group_atomic_check(struct drm_device *dev,
+			       struct drm_atomic_state *state);
+void rcar_du_group_atomic_setup(struct drm_device *dev,
+				struct drm_atomic_state *state);
+
 int rcar_du_group_init(struct rcar_du_device *rcdu, struct rcar_du_group *rgrp,
 		       unsigned int index);
 void rcar_du_group_cleanup(struct rcar_du_group *rgrp);
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_kms.c b/drivers/gpu/drm/rcar-du/rcar_du_kms.c
index d3069fb284fb..8a0c26939de2 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_kms.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_kms.c
@@ -430,6 +430,10 @@  static int rcar_du_atomic_check(struct drm_device *dev,
 	if (ret)
 		return ret;
 
+	ret = rcar_du_group_atomic_check(dev, state);
+	if (ret)
+		return ret;
+
 	if (rcar_du_has(rcdu, RCAR_DU_FEATURE_VSP1_SOURCE))
 		return 0;
 
@@ -464,6 +468,7 @@  static void rcar_du_atomic_commit_tail(struct drm_atomic_state *old_state)
 
 	/* Apply the atomic update. */
 	rcar_du_crtc_atomic_exit_standby(dev, old_state);
+	rcar_du_group_atomic_setup(dev, old_state);
 
 	drm_atomic_helper_commit_modeset_disables(dev, old_state);
 	rcar_du_crtc_atomic_modeset(dev, old_state);