drm/i915/gt: Move the [class][inst] lookup for engines onto the GT

To maintain a fast lookup from a GT centric irq handler, we want the
engine lookup tables on the intel_gt. To avoid having multiple copies of
the same multi-dimension lookup table, move the generic user engine
lookup into an rbtree (for fast and flexible indexing).

v2: Split uabi_instance cf uabi_class
v3: Set uabi_class/uabi_instance after collating all engines to provide a
stable uabi across parallel unordered construction.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com> #v2
Link: https://patchwork.freedesktop.org/patch/msgid/20190806124300.24945-2-chris@chris-wilson.co.uk

1 files changed, 228 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/gt/intel_engine_user.c b/drivers/gpu/drm/i915/gt/intel_engine_user.c
new file mode 100644
index 000000000000..68fda1ac3c60
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/intel_engine_user.c
@@ -0,0 +1,228 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2019 Intel Corporation
+ */
+
+#include <linux/list.h>
+#include <linux/list_sort.h>
+#include <linux/llist.h>
+
+#include "i915_drv.h"
+#include "intel_engine.h"
+#include "intel_engine_user.h"
+
+struct intel_engine_cs *
+intel_engine_lookup_user(struct drm_i915_private *i915, u8 class, u8 instance)
+{
+	struct rb_node *p = i915->uabi_engines.rb_node;
+
+	while (p) {
+		struct intel_engine_cs *it =
+			rb_entry(p, typeof(*it), uabi_node);
+
+		if (class < it->uabi_class)
+			p = p->rb_left;
+		else if (class > it->uabi_class ||
+			 instance > it->uabi_instance)
+			p = p->rb_right;
+		else if (instance < it->uabi_instance)
+			p = p->rb_left;
+		else
+			return it;
+	}
+
+	return NULL;
+}
+
+void intel_engine_add_user(struct intel_engine_cs *engine)
+{
+	llist_add((struct llist_node *)&engine->uabi_node,
+		  (struct llist_head *)&engine->i915->uabi_engines);
+}
+
+static const u8 uabi_classes[] = {
+	[RENDER_CLASS] = I915_ENGINE_CLASS_RENDER,
+	[COPY_ENGINE_CLASS] = I915_ENGINE_CLASS_COPY,
+	[VIDEO_DECODE_CLASS] = I915_ENGINE_CLASS_VIDEO,
+	[VIDEO_ENHANCEMENT_CLASS] = I915_ENGINE_CLASS_VIDEO_ENHANCE,
+};
+
+static int engine_cmp(void *priv, struct list_head *A, struct list_head *B)
+{
+	const struct intel_engine_cs *a =
+		container_of((struct rb_node *)A, typeof(*a), uabi_node);
+	const struct intel_engine_cs *b =
+		container_of((struct rb_node *)B, typeof(*b), uabi_node);
+
+	if (uabi_classes[a->class] < uabi_classes[b->class])
+		return -1;
+	if (uabi_classes[a->class] > uabi_classes[b->class])
+		return 1;
+
+	if (a->instance < b->instance)
+		return -1;
+	if (a->instance > b->instance)
+		return 1;
+
+	return 0;
+}
+
+static struct llist_node *get_engines(struct drm_i915_private *i915)
+{
+	return llist_del_all((struct llist_head *)&i915->uabi_engines);
+}
+
+static void sort_engines(struct drm_i915_private *i915,
+			 struct list_head *engines)
+{
+	struct llist_node *pos, *next;
+
+	llist_for_each_safe(pos, next, get_engines(i915)) {
+		struct intel_engine_cs *engine =
+			container_of((struct rb_node *)pos, typeof(*engine),
+				     uabi_node);
+		list_add((struct list_head *)&engine->uabi_node, engines);
+	}
+	list_sort(NULL, engines, engine_cmp);
+}
+
+static void set_scheduler_caps(struct drm_i915_private *i915)
+{
+	static const struct {
+		u8 engine;
+		u8 sched;
+	} map[] = {
+#define MAP(x, y) { ilog2(I915_ENGINE_##x), ilog2(I915_SCHEDULER_CAP_##y) }
+		MAP(HAS_PREEMPTION, PREEMPTION),
+		MAP(HAS_SEMAPHORES, SEMAPHORES),
+		MAP(SUPPORTS_STATS, ENGINE_BUSY_STATS),
+#undef MAP
+	};
+	struct intel_engine_cs *engine;
+	u32 enabled, disabled;
+
+	enabled = 0;
+	disabled = 0;
+	for_each_uabi_engine(engine, i915) { /* all engines must agree! */
+		int i;
+
+		if (engine->schedule)
+			enabled |= (I915_SCHEDULER_CAP_ENABLED |
+				    I915_SCHEDULER_CAP_PRIORITY);
+		else
+			disabled |= (I915_SCHEDULER_CAP_ENABLED |
+				     I915_SCHEDULER_CAP_PRIORITY);
+
+		for (i = 0; i < ARRAY_SIZE(map); i++) {
+			if (engine->flags & BIT(map[i].engine))
+				enabled |= BIT(map[i].sched);
+			else
+				disabled |= BIT(map[i].sched);
+		}
+	}
+
+	i915->caps.scheduler = enabled & ~disabled;
+	if (!(i915->caps.scheduler & I915_SCHEDULER_CAP_ENABLED))
+		i915->caps.scheduler = 0;
+}
+
+void intel_engines_driver_register(struct drm_i915_private *i915)
+{
+	u8 uabi_instances[4] = {};
+	struct list_head *it, *next;
+	struct rb_node **p, *prev;
+	LIST_HEAD(engines);
+
+	sort_engines(i915, &engines);
+
+	prev = NULL;
+	p = &i915->uabi_engines.rb_node;
+	list_for_each_safe(it, next, &engines) {
+		struct intel_engine_cs *engine =
+			container_of((struct rb_node *)it, typeof(*engine),
+				     uabi_node);
+
+		GEM_BUG_ON(engine->class >= ARRAY_SIZE(uabi_classes));
+		engine->uabi_class = uabi_classes[engine->class];
+
+		GEM_BUG_ON(engine->uabi_class >= ARRAY_SIZE(uabi_instances));
+		engine->uabi_instance = uabi_instances[engine->uabi_class]++;
+
+		rb_link_node(&engine->uabi_node, prev, p);
+		rb_insert_color(&engine->uabi_node, &i915->uabi_engines);
+
+		GEM_BUG_ON(intel_engine_lookup_user(i915,
+						    engine->uabi_class,
+						    engine->uabi_instance) != engine);
+
+		prev = &engine->uabi_node;
+		p = &prev->rb_right;
+	}
+
+	if (IS_ENABLED(CONFIG_DRM_I915_SELFTESTS) &&
+	    IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)) {
+		struct intel_engine_cs *engine;
+		unsigned int isolation;
+		int class, inst;
+		int errors = 0;
+
+		for (class = 0; class < ARRAY_SIZE(uabi_instances); class++) {
+			for (inst = 0; inst < uabi_instances[class]; inst++) {
+				engine = intel_engine_lookup_user(i915,
+								  class, inst);
+				if (!engine) {
+					pr_err("UABI engine not found for { class:%d, instance:%d }\n",
+					       class, inst);
+					errors++;
+					continue;
+				}
+
+				if (engine->uabi_class != class ||
+				    engine->uabi_instance != inst) {
+					pr_err("Wrong UABI engine:%s { class:%d, instance:%d } found for { class:%d, instance:%d }\n",
+					       engine->name,
+					       engine->uabi_class,
+					       engine->uabi_instance,
+					       class, inst);
+					errors++;
+					continue;
+				}
+			}
+		}
+
+		/*
+		 * Make sure that classes with multiple engine instances all
+		 * share the same basic configuration.
+		 */
+		isolation = intel_engines_has_context_isolation(i915);
+		for_each_uabi_engine(engine, i915) {
+			unsigned int bit = BIT(engine->uabi_class);
+			unsigned int expected = engine->default_state ? bit : 0;
+
+			if ((isolation & bit) != expected) {
+				pr_err("mismatching default context state for class %d on engine %s\n",
+				       engine->uabi_class, engine->name);
+				errors++;
+			}
+		}
+
+		if (WARN(errors, "Invalid UABI engine mapping found"))
+			i915->uabi_engines = RB_ROOT;
+	}
+
+	set_scheduler_caps(i915);
+}
+
+unsigned int intel_engines_has_context_isolation(struct drm_i915_private *i915)
+{
+	struct intel_engine_cs *engine;
+	unsigned int which;
+
+	which = 0;
+	for_each_uabi_engine(engine, i915)
+		if (engine->default_state)
+			which |= BIT(engine->uabi_class);
+
+	return which;
+}