1 /*
2  * SPDX-License-Identifier: MIT
3  *
4  * i915_sw_fence.h - library routines for N:M synchronisation points
5  *
6  * Copyright (C) 2016 Intel Corporation
7  */
8 
9 #ifndef _I915_SW_FENCE_H_
10 #define _I915_SW_FENCE_H_
11 
12 #include <linux/dma-fence.h>
13 #include <linux/gfp.h>
14 #include <linux/kref.h>
15 #include <linux/notifier.h> /* for NOTIFY_DONE */
16 #include <linux/wait.h>
17 
18 struct completion;
19 struct dma_resv;
20 
21 struct i915_sw_fence {
22 	wait_queue_head_t wait;
23 	unsigned long flags;
24 	atomic_t pending;
25 	int error;
26 };
27 
28 #define I915_SW_FENCE_CHECKED_BIT	0 /* used internally for DAG checking */
29 #define I915_SW_FENCE_PRIVATE_BIT	1 /* available for use by owner */
30 #define I915_SW_FENCE_MASK		(~3)
31 
32 enum i915_sw_fence_notify {
33 	FENCE_COMPLETE,
34 	FENCE_FREE
35 };
36 
37 typedef int (*i915_sw_fence_notify_t)(struct i915_sw_fence *,
38 				      enum i915_sw_fence_notify state);
39 #define __i915_sw_fence_call __aligned(4)
40 
41 void __i915_sw_fence_init(struct i915_sw_fence *fence,
42 			  i915_sw_fence_notify_t fn,
43 			  const char *name,
44 			  struct lock_class_key *key);
45 #ifdef CONFIG_LOCKDEP
46 #define i915_sw_fence_init(fence, fn)				\
47 do {								\
48 	static struct lock_class_key __key;			\
49 								\
50 	__i915_sw_fence_init((fence), (fn), #fence, &__key);	\
51 } while (0)
52 #else
53 #define i915_sw_fence_init(fence, fn)				\
54 	__i915_sw_fence_init((fence), (fn), NULL, NULL)
55 #endif
56 
57 void i915_sw_fence_reinit(struct i915_sw_fence *fence);
58 
59 #ifdef CONFIG_DRM_I915_SW_FENCE_DEBUG_OBJECTS
60 void i915_sw_fence_fini(struct i915_sw_fence *fence);
61 #else
62 static inline void i915_sw_fence_fini(struct i915_sw_fence *fence) {}
63 #endif
64 
65 void i915_sw_fence_commit(struct i915_sw_fence *fence);
66 
67 int i915_sw_fence_await_sw_fence(struct i915_sw_fence *fence,
68 				 struct i915_sw_fence *after,
69 				 wait_queue_entry_t *wq);
70 int i915_sw_fence_await_sw_fence_gfp(struct i915_sw_fence *fence,
71 				     struct i915_sw_fence *after,
72 				     gfp_t gfp);
73 
74 struct i915_sw_dma_fence_cb {
75 	struct dma_fence_cb base;
76 	struct i915_sw_fence *fence;
77 };
78 
79 int __i915_sw_fence_await_dma_fence(struct i915_sw_fence *fence,
80 				    struct dma_fence *dma,
81 				    struct i915_sw_dma_fence_cb *cb);
82 int i915_sw_fence_await_dma_fence(struct i915_sw_fence *fence,
83 				  struct dma_fence *dma,
84 				  unsigned long timeout,
85 				  gfp_t gfp);
86 
87 int i915_sw_fence_await_reservation(struct i915_sw_fence *fence,
88 				    struct dma_resv *resv,
89 				    const struct dma_fence_ops *exclude,
90 				    bool write,
91 				    unsigned long timeout,
92 				    gfp_t gfp);
93 
94 void i915_sw_fence_await(struct i915_sw_fence *fence);
95 void i915_sw_fence_complete(struct i915_sw_fence *fence);
96 
97 static inline bool i915_sw_fence_signaled(const struct i915_sw_fence *fence)
98 {
99 	return atomic_read(&fence->pending) <= 0;
100 }
101 
102 static inline bool i915_sw_fence_done(const struct i915_sw_fence *fence)
103 {
104 	return atomic_read(&fence->pending) < 0;
105 }
106 
107 static inline void i915_sw_fence_wait(struct i915_sw_fence *fence)
108 {
109 	wait_event(fence->wait, i915_sw_fence_done(fence));
110 }
111 
112 static inline void
113 i915_sw_fence_set_error_once(struct i915_sw_fence *fence, int error)
114 {
115 	if (unlikely(error))
116 		cmpxchg(&fence->error, 0, error);
117 }
118 
119 #endif /* _I915_SW_FENCE_H_ */
120