1 files changed, 164 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pm.c b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
new file mode 100644
index 000000000000..ccf034764741
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
@@ -0,0 +1,164 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2019 Intel Corporation
+ */
+
+#include "i915_drv.h"
+
+#include "intel_engine.h"
+#include "intel_engine_pm.h"
+#include "intel_gt_pm.h"
+
+static int __engine_unpark(struct intel_wakeref *wf)
+{
+	struct intel_engine_cs *engine =
+		container_of(wf, typeof(*engine), wakeref);
+	void *map;
+
+	GEM_TRACE("%s\n", engine->name);
+
+	intel_gt_pm_get(engine->i915);
+
+	/* Pin the default state for fast resets from atomic context. */
+	map = NULL;
+	if (engine->default_state)
+		map = i915_gem_object_pin_map(engine->default_state,
+					      I915_MAP_WB);
+	if (!IS_ERR_OR_NULL(map))
+		engine->pinned_default_state = map;
+
+	if (engine->unpark)
+		engine->unpark(engine);
+
+	intel_engine_init_hangcheck(engine);
+	return 0;
+}
+
+void intel_engine_pm_get(struct intel_engine_cs *engine)
+{
+	intel_wakeref_get(engine->i915, &engine->wakeref, __engine_unpark);
+}
+
+void intel_engine_park(struct intel_engine_cs *engine)
+{
+	/*
+	 * We are committed now to parking this engine, make sure there
+	 * will be no more interrupts arriving later and the engine
+	 * is truly idle.
+	 */
+	if (wait_for(intel_engine_is_idle(engine), 10)) {
+		struct drm_printer p = drm_debug_printer(__func__);
+
+		dev_err(engine->i915->drm.dev,
+			"%s is not idle before parking\n",
+			engine->name);
+		intel_engine_dump(engine, &p, NULL);
+	}
+}
+
+static bool switch_to_kernel_context(struct intel_engine_cs *engine)
+{
+	struct i915_request *rq;
+
+	/* Already inside the kernel context, safe to power down. */
+	if (engine->wakeref_serial == engine->serial)
+		return true;
+
+	/* GPU is pointing to the void, as good as in the kernel context. */
+	if (i915_reset_failed(engine->i915))
+		return true;
+
+	/*
+	 * Note, we do this without taking the timeline->mutex. We cannot
+	 * as we may be called while retiring the kernel context and so
+	 * already underneath the timeline->mutex. Instead we rely on the
+	 * exclusive property of the __engine_park that prevents anyone
+	 * else from creating a request on this engine. This also requires
+	 * that the ring is empty and we avoid any waits while constructing
+	 * the context, as they assume protection by the timeline->mutex.
+	 * This should hold true as we can only park the engine after
+	 * retiring the last request, thus all rings should be empty and
+	 * all timelines idle.
+	 */
+	rq = __i915_request_create(engine->kernel_context, GFP_NOWAIT);
+	if (IS_ERR(rq))
+		/* Context switch failed, hope for the best! Maybe reset? */
+		return true;
+
+	/* Check again on the next retirement. */
+	engine->wakeref_serial = engine->serial + 1;
+	__i915_request_commit(rq);
+
+	return false;
+}
+
+static int __engine_park(struct intel_wakeref *wf)
+{
+	struct intel_engine_cs *engine =
+		container_of(wf, typeof(*engine), wakeref);
+
+	/*
+	 * If one and only one request is completed between pm events,
+	 * we know that we are inside the kernel context and it is
+	 * safe to power down. (We are paranoid in case that runtime
+	 * suspend causes corruption to the active context image, and
+	 * want to avoid that impacting userspace.)
+	 */
+	if (!switch_to_kernel_context(engine))
+		return -EBUSY;
+
+	GEM_TRACE("%s\n", engine->name);
+
+	intel_engine_disarm_breadcrumbs(engine);
+
+	/* Must be reset upon idling, or we may miss the busy wakeup. */
+	GEM_BUG_ON(engine->execlists.queue_priority_hint != INT_MIN);
+
+	if (engine->park)
+		engine->park(engine);
+
+	if (engine->pinned_default_state) {
+		i915_gem_object_unpin_map(engine->default_state);
+		engine->pinned_default_state = NULL;
+	}
+
+	engine->execlists.no_priolist = false;
+
+	intel_gt_pm_put(engine->i915);
+	return 0;
+}
+
+void intel_engine_pm_put(struct intel_engine_cs *engine)
+{
+	intel_wakeref_put(engine->i915, &engine->wakeref, __engine_park);
+}
+
+void intel_engine_init__pm(struct intel_engine_cs *engine)
+{
+	intel_wakeref_init(&engine->wakeref);
+}
+
+int intel_engines_resume(struct drm_i915_private *i915)
+{
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+	int err = 0;
+
+	intel_gt_pm_get(i915);
+	for_each_engine(engine, i915, id) {
+		intel_engine_pm_get(engine);
+		engine->serial++; /* kernel context lost */
+		err = engine->resume(engine);
+		intel_engine_pm_put(engine);
+		if (err) {
+			dev_err(i915->drm.dev,
+				"Failed to restart %s (%d)\n",
+				engine->name, err);
+			break;
+		}
+	}
+	intel_gt_pm_put(i915);
+
+	return err;
+}