[PATCH v2 6/6] drm: rcar-du: Add group hooks for atomic-commit

[Kieran Bingham]

The group can now be handled independently from the CRTC tracking its
own state.

Introduce an rcar_du_group_atomic_check() call which will iterate the
CRTCs to determine the per-state use-count of the group.

This use count then allows us to determine if the group should be
configured or disabled in our commit tail through the introduction of
two new calls rcar_du_group_atomic_{pre,post}_commit().

The existing rcar_du_group_{get,put}() functions are now redundant and
removed along with their interactions in the CRTC get/put calls.

The groups share clocking with the CRTCs within the group, and so are
accessible only when one of its CRTCs has been powered through
rcar_du_crtc_atomic_exit_standby().

Signed-off-by: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx>

---
v2:
 - All register sequences now maintained.
 - Clock management is no longer handled by the group
   (_crtc_{exit,enter}_standby handles this for us)



 drivers/gpu/drm/rcar-du/rcar_du_crtc.c  |   8 --
 drivers/gpu/drm/rcar-du/rcar_du_group.c | 101 ++++++++++++++++--------
 drivers/gpu/drm/rcar-du/rcar_du_group.h |  14 +++-
 drivers/gpu/drm/rcar-du/rcar_du_kms.c   |   6 ++
 4 files changed, 85 insertions(+), 44 deletions(-)

diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
index 2606de788688..fce8bd1d9d25 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
@@ -511,14 +511,8 @@ static int rcar_du_crtc_enable(struct rcar_du_crtc *rcrtc)
 	if (ret < 0)
 		goto error_clock;
 
-	ret = rcar_du_group_get(rcrtc->group);
-	if (ret < 0)
-		goto error_group;
-
 	return 0;
 
-error_group:
-	clk_disable_unprepare(rcrtc->extclock);
 error_clock:
 	clk_disable_unprepare(rcrtc->clock);
 	return ret;
@@ -526,8 +520,6 @@ static int rcar_du_crtc_enable(struct rcar_du_crtc *rcrtc)
 
 static void rcar_du_crtc_disable(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 9c82d666f170..1f9504bca0f3 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 <drm/drm_atomic.h>
@@ -172,38 +173,6 @@ 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;
@@ -384,6 +353,74 @@ static const struct drm_private_state_funcs rcar_du_group_state_funcs = {
 	.atomic_destroy_state = rcar_du_group_atomic_destroy_state,
 };
 
+#define for_each_oldnew_group_in_state(__state, __obj, __old_state, __new_state, __i) \
+	for_each_oldnew_private_obj_in_state((__state), (__obj), (__old_state), (__new_state), (__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);
+}
+
+int rcar_du_group_atomic_check(struct drm_device *dev,
+			       struct drm_atomic_state *state)
+{
+	struct drm_crtc *crtc;
+	struct drm_crtc_state *crtc_state;
+	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 *rstate;
+
+		if (crtc_state->active_changed || crtc_state->mode_changed) {
+			rstate = rcar_du_get_group_state(state, rcrtc->group);
+			if (IS_ERR(rstate))
+				return PTR_ERR(rstate);
+
+			if (crtc_state->active)
+				rstate->use_count++;
+		}
+	}
+
+	return 0;
+}
+
+int rcar_du_group_atomic_pre_commit(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->use_count && new_state->use_count)
+			rcar_du_group_setup(rgrp);
+	}
+
+	return 0;
+}
+
+int rcar_du_group_atomic_post_commit(struct drm_device *dev,
+				     struct drm_atomic_state *state)
+{
+	return 0;
+}
+
 /*
  * rcar_du_group_init - Initialise and reset a group object
  *
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_group.h b/drivers/gpu/drm/rcar-du/rcar_du_group.h
index 4b812e167987..288c09a6d7d0 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_group.h
+++ b/drivers/gpu/drm/rcar-du/rcar_du_group.h
@@ -26,7 +26,6 @@ struct rcar_du_device;
  * @index: group index
  * @channels_mask: bitmask of populated DU channels 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
@@ -43,7 +42,6 @@ struct rcar_du_group {
 
 	unsigned int channels_mask;
 	unsigned int num_crtcs;
-	unsigned int use_count;
 	unsigned int used_crtcs;
 
 	struct mutex lock;
@@ -59,9 +57,12 @@ struct rcar_du_group {
 /**
  * struct rcar_du_group_state - Driver-specific group state
  * @state: base DRM private state
+ * @use_count: number of users of the group
  */
 struct rcar_du_group_state {
 	struct drm_private_state state;
+
+	unsigned int use_count;
 };
 
 #define to_rcar_group_state(s) \
@@ -70,14 +71,19 @@ 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);
 
 int rcar_du_set_dpad0_vsp1_routing(struct rcar_du_device *rcdu);
 
+int rcar_du_group_atomic_check(struct drm_device *dev,
+			       struct drm_atomic_state *state);
+int rcar_du_group_atomic_pre_commit(struct drm_device *dev,
+				    struct drm_atomic_state *state);
+int rcar_du_group_atomic_post_commit(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 eb01bea1ab83..77f0ff38298b 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_kms.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_kms.c
@@ -271,6 +271,10 @@ 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;
 
@@ -305,6 +309,7 @@ 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_pre_commit(dev, old_state);
 	rcar_du_crtc_atomic_pre_commit(dev, old_state);
 
 	drm_atomic_helper_commit_modeset_disables(dev, old_state);
@@ -313,6 +318,7 @@ static void rcar_du_atomic_commit_tail(struct drm_atomic_state *old_state)
 	drm_atomic_helper_commit_modeset_enables(dev, old_state);
 
 	rcar_du_crtc_atomic_post_commit(dev, old_state);
+	rcar_du_group_atomic_post_commit(dev, old_state);
 	rcar_du_crtc_atomic_enter_standby(dev, old_state);
 
 	drm_atomic_helper_commit_hw_done(old_state);
-- 
2.19.1