drm/atmel: Use drm_atomic_helper_commit

One of these drivers that predates the nonblocking support in helpers,
and hand-rolled its own thing. Entirely not anything specific here, we
can just delete it all and replace it with the helper version.

Could also perhaps use the drm_mode_config_helper_suspend/resume
stuff, for another few lines deleted. But I'm not looking at that
stuff, I'm just going through all the atomic commit functions and make
sure they have properly annotated dma-fence critical sections
everywhere.

v2:
- Also delete the workqueue (Sam)
- drop the @commit kerneldoc, I missed that one.
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Boris Brezillon <bbrezillon@kernel.org>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Ludovic Desroches <ludovic.desroches@microchip.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: https://patchwork.freedesktop.org/patch/msgid/20210121152959.1725404-7-daniel.vetter@ffwll.ch

drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c

@@ -557,103 +557,10 @@ static irqreturn_t atmel_hlcdc_dc_irq_handler(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
-struct atmel_hlcdc_dc_commit {
-	struct work_struct work;
-	struct drm_device *dev;
-	struct drm_atomic_state *state;
-};
-
-static void
-atmel_hlcdc_dc_atomic_complete(struct atmel_hlcdc_dc_commit *commit)
-{
-	struct drm_device *dev = commit->dev;
-	struct atmel_hlcdc_dc *dc = dev->dev_private;
-	struct drm_atomic_state *old_state = commit->state;
-
-	/* Apply the atomic update. */
-	drm_atomic_helper_commit_modeset_disables(dev, old_state);
-	drm_atomic_helper_commit_planes(dev, old_state, 0);
-	drm_atomic_helper_commit_modeset_enables(dev, old_state);
-
-	drm_atomic_helper_wait_for_vblanks(dev, old_state);
-
-	drm_atomic_helper_cleanup_planes(dev, old_state);
-
-	drm_atomic_state_put(old_state);
-
-	/* Complete the commit, wake up any waiter. */
-	spin_lock(&dc->commit.wait.lock);
-	dc->commit.pending = false;
-	wake_up_all_locked(&dc->commit.wait);
-	spin_unlock(&dc->commit.wait.lock);
-
-	kfree(commit);
-}
-
-static void atmel_hlcdc_dc_atomic_work(struct work_struct *work)
-{
-	struct atmel_hlcdc_dc_commit *commit =
-		container_of(work, struct atmel_hlcdc_dc_commit, work);
-
-	atmel_hlcdc_dc_atomic_complete(commit);
-}
-
-static int atmel_hlcdc_dc_atomic_commit(struct drm_device *dev,
-					struct drm_atomic_state *state,
-					bool async)
-{
-	struct atmel_hlcdc_dc *dc = dev->dev_private;
-	struct atmel_hlcdc_dc_commit *commit;
-	int ret;
-
-	ret = drm_atomic_helper_prepare_planes(dev, state);
-	if (ret)
-		return ret;
-
-	/* Allocate the commit object. */
-	commit = kzalloc(sizeof(*commit), GFP_KERNEL);
-	if (!commit) {
-		ret = -ENOMEM;
-		goto error;
-	}
-
-	INIT_WORK(&commit->work, atmel_hlcdc_dc_atomic_work);
-	commit->dev = dev;
-	commit->state = state;
-
-	spin_lock(&dc->commit.wait.lock);
-	ret = wait_event_interruptible_locked(dc->commit.wait,
-					      !dc->commit.pending);
-	if (ret == 0)
-		dc->commit.pending = true;
-	spin_unlock(&dc->commit.wait.lock);
-
-	if (ret)
-		goto err_free;
-
-	/* We have our own synchronization through the commit lock. */
-	BUG_ON(drm_atomic_helper_swap_state(state, false) < 0);
-
-	/* Swap state succeeded, this is the point of no return. */
-	drm_atomic_state_get(state);
-	if (async)
-		queue_work(dc->wq, &commit->work);
-	else
-		atmel_hlcdc_dc_atomic_complete(commit);
-
-	return 0;
-
-err_free:
-	kfree(commit);
-error:
-	drm_atomic_helper_cleanup_planes(dev, state);
-	return ret;
-}
-
 static const struct drm_mode_config_funcs mode_config_funcs = {
 	.fb_create = drm_gem_fb_create,
 	.atomic_check = drm_atomic_helper_check,
-	.atomic_commit = atmel_hlcdc_dc_atomic_commit,
+	.atomic_commit = drm_atomic_helper_commit,
 };
 
 static int atmel_hlcdc_dc_modeset_init(struct drm_device *dev)
@@ -712,11 +619,6 @@ static int atmel_hlcdc_dc_load(struct drm_device *dev)
 	if (!dc)
 		return -ENOMEM;
 
-	dc->wq = alloc_ordered_workqueue("atmel-hlcdc-dc", 0);
-	if (!dc->wq)
-		return -ENOMEM;
-
-	init_waitqueue_head(&dc->commit.wait);
 	dc->desc = match->data;
 	dc->hlcdc = dev_get_drvdata(dev->dev->parent);
 	dev->dev_private = dc;
@@ -724,7 +626,7 @@ static int atmel_hlcdc_dc_load(struct drm_device *dev)
 	ret = clk_prepare_enable(dc->hlcdc->periph_clk);
 	if (ret) {
 		dev_err(dev->dev, "failed to enable periph_clk\n");
-		goto err_destroy_wq;
+		return ret;
 	}
 
 	pm_runtime_enable(dev->dev);
@@ -761,9 +663,6 @@ static int atmel_hlcdc_dc_load(struct drm_device *dev)
 	pm_runtime_disable(dev->dev);
 	clk_disable_unprepare(dc->hlcdc->periph_clk);
 
-err_destroy_wq:
-	destroy_workqueue(dc->wq);
-
 	return ret;
 }
 
@@ -771,7 +670,6 @@ static void atmel_hlcdc_dc_unload(struct drm_device *dev)
 {
 	struct atmel_hlcdc_dc *dc = dev->dev_private;
 
-	flush_workqueue(dc->wq);
 	drm_kms_helper_poll_fini(dev);
 	drm_atomic_helper_shutdown(dev);
 	drm_mode_config_cleanup(dev);
@@ -784,7 +682,6 @@ static void atmel_hlcdc_dc_unload(struct drm_device *dev)
 
 	pm_runtime_disable(dev->dev);
 	clk_disable_unprepare(dc->hlcdc->periph_clk);
-	destroy_workqueue(dc->wq);
 }
 
 static int atmel_hlcdc_dc_irq_postinstall(struct drm_device *dev)

drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.h

@@ -331,9 +331,7 @@ struct atmel_hlcdc_dc_desc {
  * @crtc: CRTC provided by the display controller
  * @planes: instantiated planes
  * @layers: active HLCDC layers
- * @wq: display controller workqueue
  * @suspend: used to store the HLCDC state when entering suspend
- * @commit: used for async commit handling
  */
 struct atmel_hlcdc_dc {
 	const struct atmel_hlcdc_dc_desc *desc;
@@ -341,15 +339,10 @@ struct atmel_hlcdc_dc {
 	struct atmel_hlcdc *hlcdc;
 	struct drm_crtc *crtc;
 	struct atmel_hlcdc_layer *layers[ATMEL_HLCDC_MAX_LAYERS];
-	struct workqueue_struct *wq;
 	struct {
 		u32 imr;
 		struct drm_atomic_state *state;
 	} suspend;
-	struct {
-		wait_queue_head_t wait;
-		bool pending;
-	} commit;
 };
 
 extern struct atmel_hlcdc_formats atmel_hlcdc_plane_rgb_formats;