1 files changed, 95 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_fence.c b/drivers/gpu/drm/i915/gem/i915_gem_fence.c
new file mode 100644
index 000000000..8ab842c80
--- /dev/null
+++ b/drivers/gpu/drm/i915/gem/i915_gem_fence.c
@@ -0,0 +1,95 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2019 Intel Corporation
+ */
+
+#include "i915_drv.h"
+#include "i915_gem_object.h"
+
+struct stub_fence {
+	struct dma_fence dma;
+	struct i915_sw_fence chain;
+};
+
+static int __i915_sw_fence_call
+stub_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify state)
+{
+	struct stub_fence *stub = container_of(fence, typeof(*stub), chain);
+
+	switch (state) {
+	case FENCE_COMPLETE:
+		dma_fence_signal(&stub->dma);
+		break;
+
+	case FENCE_FREE:
+		dma_fence_put(&stub->dma);
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static const char *stub_driver_name(struct dma_fence *fence)
+{
+	return DRIVER_NAME;
+}
+
+static const char *stub_timeline_name(struct dma_fence *fence)
+{
+	return "object";
+}
+
+static void stub_release(struct dma_fence *fence)
+{
+	struct stub_fence *stub = container_of(fence, typeof(*stub), dma);
+
+	i915_sw_fence_fini(&stub->chain);
+
+	BUILD_BUG_ON(offsetof(typeof(*stub), dma));
+	dma_fence_free(&stub->dma);
+}
+
+static const struct dma_fence_ops stub_fence_ops = {
+	.get_driver_name = stub_driver_name,
+	.get_timeline_name = stub_timeline_name,
+	.release = stub_release,
+};
+
+struct dma_fence *
+i915_gem_object_lock_fence(struct drm_i915_gem_object *obj)
+{
+	struct stub_fence *stub;
+
+	assert_object_held(obj);
+
+	stub = kmalloc(sizeof(*stub), GFP_KERNEL);
+	if (!stub)
+		return NULL;
+
+	i915_sw_fence_init(&stub->chain, stub_notify);
+	dma_fence_init(&stub->dma, &stub_fence_ops, &stub->chain.wait.lock,
+		       0, 0);
+
+	if (i915_sw_fence_await_reservation(&stub->chain,
+					    obj->base.resv, NULL, true,
+					    i915_fence_timeout(to_i915(obj->base.dev)),
+					    I915_FENCE_GFP) < 0)
+		goto err;
+
+	dma_resv_add_excl_fence(obj->base.resv, &stub->dma);
+
+	return &stub->dma;
+
+err:
+	stub_release(&stub->dma);
+	return NULL;
+}
+
+void i915_gem_object_unlock_fence(struct drm_i915_gem_object *obj,
+				  struct dma_fence *fence)
+{
+	struct stub_fence *stub = container_of(fence, typeof(*stub), dma);
+
+	i915_sw_fence_commit(&stub->chain);
+}