1 files changed, 103 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_frontbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_object_frontbuffer.c
new file mode 100644
index 000000000000..aaa15e7b3f17
--- /dev/null
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object_frontbuffer.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: MIT
+/* Copyright © 2025 Intel Corporation */
+
+#include "i915_drv.h"
+#include "i915_gem_object_frontbuffer.h"
+
+static int frontbuffer_active(struct i915_active *ref)
+{
+	struct i915_frontbuffer *front =
+		container_of(ref, typeof(*front), write);
+
+	kref_get(&front->ref);
+	return 0;
+}
+
+static void frontbuffer_retire(struct i915_active *ref)
+{
+	struct i915_frontbuffer *front =
+		container_of(ref, typeof(*front), write);
+
+	intel_frontbuffer_flush(&front->base, ORIGIN_CS);
+	i915_gem_object_frontbuffer_put(front);
+}
+
+struct i915_frontbuffer *
+i915_gem_object_frontbuffer_get(struct drm_i915_gem_object *obj)
+{
+	struct drm_i915_private *i915 = to_i915(obj->base.dev);
+	struct i915_frontbuffer *front, *cur;
+
+	front = i915_gem_object_frontbuffer_lookup(obj);
+	if (front)
+		return front;
+
+	front = kmalloc(sizeof(*front), GFP_KERNEL);
+	if (!front)
+		return NULL;
+
+	intel_frontbuffer_init(&front->base, &i915->drm);
+
+	kref_init(&front->ref);
+	i915_gem_object_get(obj);
+	front->obj = obj;
+
+	i915_active_init(&front->write,
+			 frontbuffer_active,
+			 frontbuffer_retire,
+			 I915_ACTIVE_RETIRE_SLEEPS);
+
+	spin_lock(&i915->frontbuffer_lock);
+	if (rcu_access_pointer(obj->frontbuffer)) {
+		cur = rcu_dereference_protected(obj->frontbuffer, true);
+		kref_get(&cur->ref);
+	} else {
+		cur = front;
+		rcu_assign_pointer(obj->frontbuffer, front);
+	}
+	spin_unlock(&i915->frontbuffer_lock);
+
+	if (cur != front) {
+		i915_gem_object_put(obj);
+		intel_frontbuffer_fini(&front->base);
+		kfree(front);
+	}
+
+	return cur;
+}
+
+void i915_gem_object_frontbuffer_ref(struct i915_frontbuffer *front)
+{
+	kref_get(&front->ref);
+}
+
+static void frontbuffer_release(struct kref *ref)
+	__releases(&i915->frontbuffer_lock)
+{
+	struct i915_frontbuffer *front =
+		container_of(ref, typeof(*front), ref);
+	struct drm_i915_gem_object *obj = front->obj;
+	struct drm_i915_private *i915 = to_i915(obj->base.dev);
+
+	i915_ggtt_clear_scanout(obj);
+
+	RCU_INIT_POINTER(obj->frontbuffer, NULL);
+
+	spin_unlock(&i915->frontbuffer_lock);
+
+	i915_active_fini(&front->write);
+
+	i915_gem_object_put(obj);
+
+	intel_frontbuffer_fini(&front->base);
+
+	kfree_rcu(front, rcu);
+}
+
+void i915_gem_object_frontbuffer_put(struct i915_frontbuffer *front)
+{
+	struct drm_i915_private *i915 = to_i915(front->obj->base.dev);
+
+	kref_put_lock(&front->ref, frontbuffer_release,
+		      &i915->frontbuffer_lock);
+}