1/*
 2 * SPDX-License-Identifier: MIT
 3 *
 4 * Copyright © 2019 Intel Corporation
 5 */
 6
 7#include "i915_drv.h"
 8#include "i915_gem_object.h"
 9
10struct stub_fence {
11	struct dma_fence dma;
12	struct i915_sw_fence chain;
13};
14
15static int __i915_sw_fence_call
16stub_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify state)
17{
18	struct stub_fence *stub = container_of(fence, typeof(*stub), chain);
19
20	switch (state) {
21	case FENCE_COMPLETE:
22		dma_fence_signal(&stub->dma);
23		break;
24
25	case FENCE_FREE:
26		dma_fence_put(&stub->dma);
27		break;
28	}
29
30	return NOTIFY_DONE;
31}
32
33static const char *stub_driver_name(struct dma_fence *fence)
34{
35	return DRIVER_NAME;
36}
37
38static const char *stub_timeline_name(struct dma_fence *fence)
39{
40	return "object";
41}
42
43static void stub_release(struct dma_fence *fence)
44{
45	struct stub_fence *stub = container_of(fence, typeof(*stub), dma);
46
47	i915_sw_fence_fini(&stub->chain);
48
49	BUILD_BUG_ON(offsetof(typeof(*stub), dma));
50	dma_fence_free(&stub->dma);
51}
52
53static const struct dma_fence_ops stub_fence_ops = {
54	.get_driver_name = stub_driver_name,
55	.get_timeline_name = stub_timeline_name,
56	.release = stub_release,
57};
58
59struct dma_fence *
60i915_gem_object_lock_fence(struct drm_i915_gem_object *obj)
61{
62	struct stub_fence *stub;
63
64	assert_object_held(obj);
65
66	stub = kmalloc(sizeof(*stub), GFP_KERNEL);
67	if (!stub)
68		return NULL;
69
70	i915_sw_fence_init(&stub->chain, stub_notify);
71	dma_fence_init(&stub->dma, &stub_fence_ops, &stub->chain.wait.lock,
72		       0, 0);
73
74	if (i915_sw_fence_await_reservation(&stub->chain,
75					    obj->base.resv, NULL,
76					    true, I915_FENCE_TIMEOUT,
77					    I915_FENCE_GFP) < 0)
78		goto err;
79
80	dma_resv_add_excl_fence(obj->base.resv, &stub->dma);
81
82	return &stub->dma;
83
84err:
85	stub_release(&stub->dma);
86	return NULL;
87}
88
89void i915_gem_object_unlock_fence(struct drm_i915_gem_object *obj,
90				  struct dma_fence *fence)
91{
92	struct stub_fence *stub = container_of(fence, typeof(*stub), dma);
93
94	i915_sw_fence_commit(&stub->chain);
95}