[DPU PATCH 06/11] drm/msm: Remove msm_commit/kthread, use atomic helper commit

[Sean Paul <seanpaul-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>]

Moving further towards switching fully to the the atomic helpers, this
patch removes the hand-rolled kthread nonblock commit code and uses the
atomic helpers commit_work model.

There's still a lot of copypasta here, but it's still needed to
facilitate the swap_state and prepare_fence private functions. These
will be sorted out in a follow-on patch.

Change-Id: I9fcba27824ba63d3fab96cb2bc194bfa6f3475b7
Signed-off-by: Sean Paul <seanpaul@chromium.org>
---
 drivers/gpu/drm/msm/msm_atomic.c | 199 ++++++-------------------------
 drivers/gpu/drm/msm/msm_drv.c    |   1 -
 drivers/gpu/drm/msm/msm_drv.h    |   4 -
 3 files changed, 35 insertions(+), 169 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_atomic.c b/drivers/gpu/drm/msm/msm_atomic.c
index 3a18bd3dc215..7e54eb65d096 100644
--- a/drivers/gpu/drm/msm/msm_atomic.c
+++ b/drivers/gpu/drm/msm/msm_atomic.c
@@ -21,51 +21,6 @@
 #include "msm_gem.h"
 #include "msm_fence.h"
 
-struct msm_commit {
-	struct drm_device *dev;
-	struct drm_atomic_state *state;
-	uint32_t crtc_mask;
-	bool nonblock;
-	struct kthread_work commit_work;
-};
-
-/* block until specified crtcs are no longer pending update, and
- * atomically mark them as pending update
- */
-static int start_atomic(struct msm_drm_private *priv, uint32_t crtc_mask)
-{
-	int ret;
-
-	spin_lock(&priv->pending_crtcs_event.lock);
-	ret = wait_event_interruptible_locked(priv->pending_crtcs_event,
-			!(priv->pending_crtcs & crtc_mask));
-	if (ret == 0) {
-		DBG("start: %08x", crtc_mask);
-		priv->pending_crtcs |= crtc_mask;
-	}
-	spin_unlock(&priv->pending_crtcs_event.lock);
-
-	return ret;
-}
-
-/* clear specified crtcs (no longer pending update)
- */
-static void end_atomic(struct msm_drm_private *priv, uint32_t crtc_mask)
-{
-	spin_lock(&priv->pending_crtcs_event.lock);
-	DBG("end: %08x", crtc_mask);
-	priv->pending_crtcs &= ~crtc_mask;
-	wake_up_all_locked(&priv->pending_crtcs_event);
-	spin_unlock(&priv->pending_crtcs_event.lock);
-}
-
-static void commit_destroy(struct msm_commit *c)
-{
-	end_atomic(c->dev->dev_private, c->crtc_mask);
-	if (c->nonblock)
-		kfree(c);
-}
-
 static void msm_atomic_wait_for_commit_done(
 		struct drm_device *dev,
 		struct drm_atomic_state *old_state)
@@ -118,6 +73,10 @@ static void msm_atomic_commit_tail(struct drm_atomic_state *state)
 
 	msm_atomic_wait_for_commit_done(dev, state);
 
+	drm_atomic_helper_commit_hw_done(state);
+
+	drm_atomic_helper_wait_for_vblanks(dev, state);
+
 	drm_atomic_helper_cleanup_planes(dev, state);
 
 	kms->funcs->complete_commit(kms, state);
@@ -126,109 +85,25 @@ static void msm_atomic_commit_tail(struct drm_atomic_state *state)
 /* The (potentially) asynchronous part of the commit.  At this point
  * nothing can fail short of armageddon.
  */
-static void complete_commit(struct msm_commit *c)
+static void commit_tail(struct drm_atomic_state *state)
 {
-	struct drm_atomic_state *state = c->state;
-	struct drm_device *dev = state->dev;
+	drm_atomic_helper_wait_for_fences(state->dev, state, false);
 
-	drm_atomic_helper_wait_for_fences(dev, state, false);
+	drm_atomic_helper_wait_for_dependencies(state);
 
 	msm_atomic_commit_tail(state);
 
-	drm_atomic_state_put(state);
-}
-
-static void _msm_drm_commit_work_cb(struct kthread_work *work)
-{
-	struct msm_commit *commit =  NULL;
-
-	if (!work) {
-		DRM_ERROR("%s: Invalid commit work data!\n", __func__);
-		return;
-	}
-
-	commit = container_of(work, struct msm_commit, commit_work);
-
-	complete_commit(commit);
-
-	commit_destroy(commit);
-}
-
-static struct msm_commit *commit_init(struct drm_atomic_state *state,
-		bool nonblock)
-{
-	struct msm_commit *c = kzalloc(sizeof(*c), GFP_KERNEL);
+	drm_atomic_helper_commit_cleanup_done(state);
 
-	if (!c)
-		return NULL;
-
-	c->dev = state->dev;
-	c->state = state;
-	c->nonblock = nonblock;
-
-	kthread_init_work(&c->commit_work, _msm_drm_commit_work_cb);
-
-	return c;
+	drm_atomic_state_put(state);
 }
 
-/* Start display thread function */
-static void msm_atomic_commit_dispatch(struct drm_device *dev,
-		struct drm_atomic_state *state, struct msm_commit *commit)
+static void commit_work(struct work_struct *work)
 {
-	struct msm_drm_private *priv = dev->dev_private;
-	struct drm_crtc *crtc = NULL;
-	struct drm_crtc_state *new_crtc_state = NULL;
-	int ret = -EINVAL, i = 0, j = 0;
-	bool nonblock;
-
-	/* cache since work will kfree commit in non-blocking case */
-	nonblock = commit->nonblock;
-
-	for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) {
-		for (j = 0; j < priv->num_crtcs; j++) {
-			if (priv->disp_thread[j].crtc_id ==
-						crtc->base.id) {
-				if (priv->disp_thread[j].thread) {
-					kthread_queue_work(
-						&priv->disp_thread[j].worker,
-							&commit->commit_work);
-					/* only return zero if work is
-					 * queued successfully.
-					 */
-					ret = 0;
-				} else {
-					DRM_ERROR(" Error for crtc_id: %d\n",
-						priv->disp_thread[j].crtc_id);
-				}
-				break;
-			}
-		}
-		/*
-		 * TODO: handle cases where there will be more than
-		 * one crtc per commit cycle. Remove this check then.
-		 * Current assumption is there will be only one crtc
-		 * per commit cycle.
-		 */
-		if (j < priv->num_crtcs)
-			break;
-	}
-
-	if (ret) {
-		/**
-		 * this is not expected to happen, but at this point the state
-		 * has been swapped, but we couldn't dispatch to a crtc thread.
-		 * fallback now to a synchronous complete_commit to try and
-		 * ensure that SW and HW state don't get out of sync.
-		 */
-		DRM_ERROR("failed to dispatch commit to any CRTC\n");
-		complete_commit(commit);
-	} else if (!nonblock) {
-		kthread_flush_work(&commit->commit_work);
-	}
-
-	/* free nonblocking commits in this context, after processing */
-	if (!nonblock)
-		kfree(commit);
+	struct drm_atomic_state *state = container_of(work,
+						      struct drm_atomic_state,
+						      commit_work);
+	commit_tail(state);
 }
 
 /**
@@ -247,17 +122,12 @@ int msm_atomic_commit(struct drm_device *dev,
 		struct drm_atomic_state *state, bool nonblock)
 {
 	struct msm_drm_private *priv = dev->dev_private;
-	struct msm_commit *c;
 	struct drm_crtc *crtc;
 	struct drm_crtc_state *crtc_state;
 	struct drm_plane *plane;
 	struct drm_plane_state *old_plane_state, *new_plane_state;
 	int i, ret;
 
-	ret = drm_atomic_helper_prepare_planes(dev, state);
-	if (ret)
-		return ret;
-
 	/*
 	 * Note that plane->atomic_async_check() should fail if we need
 	 * to re-assign hwpipe or anything that touches global atomic
@@ -265,32 +135,30 @@ int msm_atomic_commit(struct drm_device *dev,
 	 * cases.
 	 */
 	if (state->async_update) {
+		ret = drm_atomic_helper_prepare_planes(dev, state);
+		if (ret)
+			return ret;
+
 		drm_atomic_helper_async_commit(dev, state);
 		drm_atomic_helper_cleanup_planes(dev, state);
 		return 0;
 	}
 
-	c = commit_init(state, nonblock);
-	if (!c) {
-		ret = -ENOMEM;
-		goto error;
-	}
+	ret = drm_atomic_helper_setup_commit(state, nonblock);
+	if (ret)
+		return ret;
 
-	/*
-	 * Figure out what crtcs we have:
-	 */
-	for_each_new_crtc_in_state(state, crtc, crtc_state, i)
-		c->crtc_mask |= drm_crtc_mask(crtc);
+	INIT_WORK(&state->commit_work, commit_work);
 
-	/*
-	 * Wait for pending updates on any of the same crtc's and then
-	 * mark our set of crtc's as busy:
-	 */
-	ret = start_atomic(dev->dev_private, c->crtc_mask);
+	ret = drm_atomic_helper_prepare_planes(dev, state);
 	if (ret)
-		goto err_free;
+		return ret;
 
-	BUG_ON(drm_atomic_helper_swap_state(state, false) < 0);
+	if (!nonblock) {
+		ret = drm_atomic_helper_wait_for_fences(dev, state, true);
+		if (ret)
+			goto error;
+	}
 
 	/*
 	 * This is the point of no return - everything below never fails except
@@ -299,6 +167,8 @@ int msm_atomic_commit(struct drm_device *dev,
 	 *
 	 * swap driver private state while still holding state_lock
 	 */
+	BUG_ON(drm_atomic_helper_swap_state(state, false) < 0);
+
 	if (to_kms_state(state)->state)
 		priv->kms->funcs->swap_state(priv->kms, state);
 
@@ -329,12 +199,13 @@ int msm_atomic_commit(struct drm_device *dev,
 	 */
 
 	drm_atomic_state_get(state);
-	msm_atomic_commit_dispatch(dev, state, c);
+	if (nonblock)
+		queue_work(system_unbound_wq, &state->commit_work);
+	else
+		commit_tail(state);
 
 	return 0;
 
-err_free:
-	kfree(c);
 error:
 	drm_atomic_helper_cleanup_planes(dev, state);
 	return ret;
diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index eda4a2340f93..b354424cccb5 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -549,7 +549,6 @@ static int msm_drm_init(struct device *dev, struct drm_driver *drv)
 		goto mdss_init_fail;
 
 	priv->wq = alloc_ordered_workqueue("msm_drm", 0);
-	init_waitqueue_head(&priv->pending_crtcs_event);
 
 	INIT_LIST_HEAD(&priv->client_event_list);
 	INIT_LIST_HEAD(&priv->inactive_list);
diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
index cf96a85f4b55..292496b682e8 100644
--- a/drivers/gpu/drm/msm/msm_drv.h
+++ b/drivers/gpu/drm/msm/msm_drv.h
@@ -536,10 +536,6 @@ struct msm_drm_private {
 
 	struct workqueue_struct *wq;
 
-	/* crtcs pending async atomic updates: */
-	uint32_t pending_crtcs;
-	wait_queue_head_t pending_crtcs_event;
-
 	unsigned int num_planes;
 	struct drm_plane *planes[MAX_PLANES];
 
-- 
Sean Paul, Software Engineer, Google / Chromium OS

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