1 files changed, 251 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_requests.c b/drivers/gpu/drm/i915/gt/intel_gt_requests.c
new file mode 100644
index 000000000..cca285185
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/intel_gt_requests.c
@@ -0,0 +1,251 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2019 Intel Corporation
+ */
+
+#include <linux/workqueue.h>
+
+#include "i915_drv.h" /* for_each_engine() */
+#include "i915_request.h"
+#include "intel_engine_heartbeat.h"
+#include "intel_gt.h"
+#include "intel_gt_pm.h"
+#include "intel_gt_requests.h"
+#include "intel_timeline.h"
+
+static bool retire_requests(struct intel_timeline *tl)
+{
+	struct i915_request *rq, *rn;
+
+	list_for_each_entry_safe(rq, rn, &tl->requests, link)
+		if (!i915_request_retire(rq))
+			return false;
+
+	/* And check nothing new was submitted */
+	return !i915_active_fence_isset(&tl->last_request);
+}
+
+static bool engine_active(const struct intel_engine_cs *engine)
+{
+	return !list_empty(&engine->kernel_context->timeline->requests);
+}
+
+static bool flush_submission(struct intel_gt *gt, long timeout)
+{
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+	bool active = false;
+
+	if (!timeout)
+		return false;
+
+	if (!intel_gt_pm_is_awake(gt))
+		return false;
+
+	for_each_engine(engine, gt, id) {
+		intel_engine_flush_submission(engine);
+
+		/* Flush the background retirement and idle barriers */
+		flush_work(&engine->retire_work);
+		flush_delayed_work(&engine->wakeref.work);
+
+		/* Is the idle barrier still outstanding? */
+		active |= engine_active(engine);
+	}
+
+	return active;
+}
+
+static void engine_retire(struct work_struct *work)
+{
+	struct intel_engine_cs *engine =
+		container_of(work, typeof(*engine), retire_work);
+	struct intel_timeline *tl = xchg(&engine->retire, NULL);
+
+	do {
+		struct intel_timeline *next = xchg(&tl->retire, NULL);
+
+		/*
+		 * Our goal here is to retire _idle_ timelines as soon as
+		 * possible (as they are idle, we do not expect userspace
+		 * to be cleaning up anytime soon).
+		 *
+		 * If the timeline is currently locked, either it is being
+		 * retired elsewhere or about to be!
+		 */
+		if (mutex_trylock(&tl->mutex)) {
+			retire_requests(tl);
+			mutex_unlock(&tl->mutex);
+		}
+		intel_timeline_put(tl);
+
+		GEM_BUG_ON(!next);
+		tl = ptr_mask_bits(next, 1);
+	} while (tl);
+}
+
+static bool add_retire(struct intel_engine_cs *engine,
+		       struct intel_timeline *tl)
+{
+#define STUB ((struct intel_timeline *)1)
+	struct intel_timeline *first;
+
+	/*
+	 * We open-code a llist here to include the additional tag [BIT(0)]
+	 * so that we know when the timeline is already on a
+	 * retirement queue: either this engine or another.
+	 */
+
+	if (cmpxchg(&tl->retire, NULL, STUB)) /* already queued */
+		return false;
+
+	intel_timeline_get(tl);
+	first = READ_ONCE(engine->retire);
+	do
+		tl->retire = ptr_pack_bits(first, 1, 1);
+	while (!try_cmpxchg(&engine->retire, &first, tl));
+
+	return !first;
+}
+
+void intel_engine_add_retire(struct intel_engine_cs *engine,
+			     struct intel_timeline *tl)
+{
+	/* We don't deal well with the engine disappearing beneath us */
+	GEM_BUG_ON(intel_engine_is_virtual(engine));
+
+	if (add_retire(engine, tl))
+		schedule_work(&engine->retire_work);
+}
+
+void intel_engine_init_retire(struct intel_engine_cs *engine)
+{
+	INIT_WORK(&engine->retire_work, engine_retire);
+}
+
+void intel_engine_fini_retire(struct intel_engine_cs *engine)
+{
+	flush_work(&engine->retire_work);
+	GEM_BUG_ON(engine->retire);
+}
+
+long intel_gt_retire_requests_timeout(struct intel_gt *gt, long timeout)
+{
+	struct intel_gt_timelines *timelines = &gt->timelines;
+	struct intel_timeline *tl, *tn;
+	unsigned long active_count = 0;
+	bool interruptible;
+	LIST_HEAD(free);
+
+	interruptible = true;
+	if (unlikely(timeout < 0))
+		timeout = -timeout, interruptible = false;
+
+	flush_submission(gt, timeout); /* kick the ksoftirqd tasklets */
+	spin_lock(&timelines->lock);
+	list_for_each_entry_safe(tl, tn, &timelines->active_list, link) {
+		if (!mutex_trylock(&tl->mutex)) {
+			active_count++; /* report busy to caller, try again? */
+			continue;
+		}
+
+		intel_timeline_get(tl);
+		GEM_BUG_ON(!atomic_read(&tl->active_count));
+		atomic_inc(&tl->active_count); /* pin the list element */
+		spin_unlock(&timelines->lock);
+
+		if (timeout > 0) {
+			struct dma_fence *fence;
+
+			fence = i915_active_fence_get(&tl->last_request);
+			if (fence) {
+				mutex_unlock(&tl->mutex);
+
+				timeout = dma_fence_wait_timeout(fence,
+								 interruptible,
+								 timeout);
+				dma_fence_put(fence);
+
+				/* Retirement is best effort */
+				if (!mutex_trylock(&tl->mutex)) {
+					active_count++;
+					goto out_active;
+				}
+			}
+		}
+
+		if (!retire_requests(tl))
+			active_count++;
+		mutex_unlock(&tl->mutex);
+
+out_active:	spin_lock(&timelines->lock);
+
+		/* Resume list iteration after reacquiring spinlock */
+		list_safe_reset_next(tl, tn, link);
+		if (atomic_dec_and_test(&tl->active_count))
+			list_del(&tl->link);
+
+		/* Defer the final release to after the spinlock */
+		if (refcount_dec_and_test(&tl->kref.refcount)) {
+			GEM_BUG_ON(atomic_read(&tl->active_count));
+			list_add(&tl->link, &free);
+		}
+	}
+	spin_unlock(&timelines->lock);
+
+	list_for_each_entry_safe(tl, tn, &free, link)
+		__intel_timeline_free(&tl->kref);
+
+	if (flush_submission(gt, timeout)) /* Wait, there's more! */
+		active_count++;
+
+	return active_count ? timeout ?: -ETIME : 0;
+}
+
+int intel_gt_wait_for_idle(struct intel_gt *gt, long timeout)
+{
+	/* If the device is asleep, we have no requests outstanding */
+	if (!intel_gt_pm_is_awake(gt))
+		return 0;
+
+	while ((timeout = intel_gt_retire_requests_timeout(gt, timeout)) > 0) {
+		cond_resched();
+		if (signal_pending(current))
+			return -EINTR;
+	}
+
+	return timeout;
+}
+
+static void retire_work_handler(struct work_struct *work)
+{
+	struct intel_gt *gt =
+		container_of(work, typeof(*gt), requests.retire_work.work);
+
+	schedule_delayed_work(&gt->requests.retire_work,
+			      round_jiffies_up_relative(HZ));
+	intel_gt_retire_requests(gt);
+}
+
+void intel_gt_init_requests(struct intel_gt *gt)
+{
+	INIT_DELAYED_WORK(&gt->requests.retire_work, retire_work_handler);
+}
+
+void intel_gt_park_requests(struct intel_gt *gt)
+{
+	cancel_delayed_work(&gt->requests.retire_work);
+}
+
+void intel_gt_unpark_requests(struct intel_gt *gt)
+{
+	schedule_delayed_work(&gt->requests.retire_work,
+			      round_jiffies_up_relative(HZ));
+}
+
+void intel_gt_fini_requests(struct intel_gt *gt)
+{
+	/* Wait until the work is marked as finished before unloading! */
+	cancel_delayed_work_sync(&gt->requests.retire_work);
+}