1 files changed, 268 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c
new file mode 100644
index 000000000000..ebd1e5919a4a
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/intel_context.c
@@ -0,0 +1,268 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2019 Intel Corporation
+ */
+
+#include "i915_drv.h"
+#include "i915_gem_context.h"
+#include "i915_globals.h"
+
+#include "intel_context.h"
+#include "intel_engine.h"
+
+static struct i915_global_context {
+	struct i915_global base;
+	struct kmem_cache *slab_ce;
+} global;
+
+struct intel_context *intel_context_alloc(void)
+{
+	return kmem_cache_zalloc(global.slab_ce, GFP_KERNEL);
+}
+
+void intel_context_free(struct intel_context *ce)
+{
+	kmem_cache_free(global.slab_ce, ce);
+}
+
+struct intel_context *
+intel_context_lookup(struct i915_gem_context *ctx,
+		     struct intel_engine_cs *engine)
+{
+	struct intel_context *ce = NULL;
+	struct rb_node *p;
+
+	spin_lock(&ctx->hw_contexts_lock);
+	p = ctx->hw_contexts.rb_node;
+	while (p) {
+		struct intel_context *this =
+			rb_entry(p, struct intel_context, node);
+
+		if (this->engine == engine) {
+			GEM_BUG_ON(this->gem_context != ctx);
+			ce = this;
+			break;
+		}
+
+		if (this->engine < engine)
+			p = p->rb_right;
+		else
+			p = p->rb_left;
+	}
+	spin_unlock(&ctx->hw_contexts_lock);
+
+	return ce;
+}
+
+struct intel_context *
+__intel_context_insert(struct i915_gem_context *ctx,
+		       struct intel_engine_cs *engine,
+		       struct intel_context *ce)
+{
+	struct rb_node **p, *parent;
+	int err = 0;
+
+	spin_lock(&ctx->hw_contexts_lock);
+
+	parent = NULL;
+	p = &ctx->hw_contexts.rb_node;
+	while (*p) {
+		struct intel_context *this;
+
+		parent = *p;
+		this = rb_entry(parent, struct intel_context, node);
+
+		if (this->engine == engine) {
+			err = -EEXIST;
+			ce = this;
+			break;
+		}
+
+		if (this->engine < engine)
+			p = &parent->rb_right;
+		else
+			p = &parent->rb_left;
+	}
+	if (!err) {
+		rb_link_node(&ce->node, parent, p);
+		rb_insert_color(&ce->node, &ctx->hw_contexts);
+	}
+
+	spin_unlock(&ctx->hw_contexts_lock);
+
+	return ce;
+}
+
+void __intel_context_remove(struct intel_context *ce)
+{
+	struct i915_gem_context *ctx = ce->gem_context;
+
+	spin_lock(&ctx->hw_contexts_lock);
+	rb_erase(&ce->node, &ctx->hw_contexts);
+	spin_unlock(&ctx->hw_contexts_lock);
+}
+
+static struct intel_context *
+intel_context_instance(struct i915_gem_context *ctx,
+		       struct intel_engine_cs *engine)
+{
+	struct intel_context *ce, *pos;
+
+	ce = intel_context_lookup(ctx, engine);
+	if (likely(ce))
+		return ce;
+
+	ce = intel_context_alloc();
+	if (!ce)
+		return ERR_PTR(-ENOMEM);
+
+	intel_context_init(ce, ctx, engine);
+
+	pos = __intel_context_insert(ctx, engine, ce);
+	if (unlikely(pos != ce)) /* Beaten! Use their HW context instead */
+		intel_context_free(ce);
+
+	GEM_BUG_ON(intel_context_lookup(ctx, engine) != pos);
+	return pos;
+}
+
+struct intel_context *
+intel_context_pin_lock(struct i915_gem_context *ctx,
+		       struct intel_engine_cs *engine)
+	__acquires(ce->pin_mutex)
+{
+	struct intel_context *ce;
+
+	ce = intel_context_instance(ctx, engine);
+	if (IS_ERR(ce))
+		return ce;
+
+	if (mutex_lock_interruptible(&ce->pin_mutex))
+		return ERR_PTR(-EINTR);
+
+	return ce;
+}
+
+struct intel_context *
+intel_context_pin(struct i915_gem_context *ctx,
+		  struct intel_engine_cs *engine)
+{
+	struct intel_context *ce;
+	int err;
+
+	ce = intel_context_instance(ctx, engine);
+	if (IS_ERR(ce))
+		return ce;
+
+	if (likely(atomic_inc_not_zero(&ce->pin_count)))
+		return ce;
+
+	if (mutex_lock_interruptible(&ce->pin_mutex))
+		return ERR_PTR(-EINTR);
+
+	if (likely(!atomic_read(&ce->pin_count))) {
+		err = ce->ops->pin(ce);
+		if (err)
+			goto err;
+
+		i915_gem_context_get(ctx);
+		GEM_BUG_ON(ce->gem_context != ctx);
+
+		mutex_lock(&ctx->mutex);
+		list_add(&ce->active_link, &ctx->active_engines);
+		mutex_unlock(&ctx->mutex);
+
+		intel_context_get(ce);
+		smp_mb__before_atomic(); /* flush pin before it is visible */
+	}
+
+	atomic_inc(&ce->pin_count);
+	GEM_BUG_ON(!intel_context_is_pinned(ce)); /* no overflow! */
+
+	mutex_unlock(&ce->pin_mutex);
+	return ce;
+
+err:
+	mutex_unlock(&ce->pin_mutex);
+	return ERR_PTR(err);
+}
+
+void intel_context_unpin(struct intel_context *ce)
+{
+	if (likely(atomic_add_unless(&ce->pin_count, -1, 1)))
+		return;
+
+	/* We may be called from inside intel_context_pin() to evict another */
+	intel_context_get(ce);
+	mutex_lock_nested(&ce->pin_mutex, SINGLE_DEPTH_NESTING);
+
+	if (likely(atomic_dec_and_test(&ce->pin_count))) {
+		ce->ops->unpin(ce);
+
+		mutex_lock(&ce->gem_context->mutex);
+		list_del(&ce->active_link);
+		mutex_unlock(&ce->gem_context->mutex);
+
+		i915_gem_context_put(ce->gem_context);
+		intel_context_put(ce);
+	}
+
+	mutex_unlock(&ce->pin_mutex);
+	intel_context_put(ce);
+}
+
+static void intel_context_retire(struct i915_active_request *active,
+				 struct i915_request *rq)
+{
+	struct intel_context *ce =
+		container_of(active, typeof(*ce), active_tracker);
+
+	intel_context_unpin(ce);
+}
+
+void
+intel_context_init(struct intel_context *ce,
+		   struct i915_gem_context *ctx,
+		   struct intel_engine_cs *engine)
+{
+	kref_init(&ce->ref);
+
+	ce->gem_context = ctx;
+	ce->engine = engine;
+	ce->ops = engine->cops;
+	ce->sseu = engine->sseu;
+
+	INIT_LIST_HEAD(&ce->signal_link);
+	INIT_LIST_HEAD(&ce->signals);
+
+	mutex_init(&ce->pin_mutex);
+
+	i915_active_request_init(&ce->active_tracker,
+				 NULL, intel_context_retire);
+}
+
+static void i915_global_context_shrink(void)
+{
+	kmem_cache_shrink(global.slab_ce);
+}
+
+static void i915_global_context_exit(void)
+{
+	kmem_cache_destroy(global.slab_ce);
+}
+
+static struct i915_global_context global = { {
+	.shrink = i915_global_context_shrink,
+	.exit = i915_global_context_exit,
+} };
+
+int __init i915_global_context_init(void)
+{
+	global.slab_ce = KMEM_CACHE(intel_context, SLAB_HWCACHE_ALIGN);
+	if (!global.slab_ce)
+		return -ENOMEM;
+
+	i915_global_register(&global.base);
+	return 0;
+}