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
 18struct completion;
 19struct dma_resv;
 20struct i915_sw_fence;
 21
 22enum i915_sw_fence_notify {
 23	FENCE_COMPLETE,
 24	FENCE_FREE
 25};
 26
 27typedef int (*i915_sw_fence_notify_t)(struct i915_sw_fence *,
 28				      enum i915_sw_fence_notify state);
 29
 30struct i915_sw_fence {
 31	wait_queue_head_t wait;
 32	i915_sw_fence_notify_t fn;
 33#ifdef CONFIG_DRM_I915_SW_FENCE_CHECK_DAG
 34	unsigned long flags;
 35#endif
 36	atomic_t pending;
 37	int error;
 38};
 39
 40#define I915_SW_FENCE_CHECKED_BIT	0 /* used internally for DAG checking */
 41
 42void __i915_sw_fence_init(struct i915_sw_fence *fence,
 43			  i915_sw_fence_notify_t fn,
 44			  const char *name,
 45			  struct lock_class_key *key);
 46#ifdef CONFIG_LOCKDEP
 47#define i915_sw_fence_init(fence, fn)				\
 48do {								\
 49	static struct lock_class_key __key;			\
 50								\
 51	BUILD_BUG_ON((fn) == NULL);				\
 52	__i915_sw_fence_init((fence), (fn), #fence, &__key);	\
 53} while (0)
 54#else
 55#define i915_sw_fence_init(fence, fn)				\
 56do {								\
 57	BUILD_BUG_ON((fn) == NULL);				\
 58	__i915_sw_fence_init((fence), (fn), NULL, NULL);	\
 59} while (0)
 60#endif
 61
 62void i915_sw_fence_reinit(struct i915_sw_fence *fence);
 63
 64#ifdef CONFIG_DRM_I915_SW_FENCE_DEBUG_OBJECTS
 65void i915_sw_fence_fini(struct i915_sw_fence *fence);
 66#else
 67static inline void i915_sw_fence_fini(struct i915_sw_fence *fence) {}
 68#endif
 69
 70void i915_sw_fence_commit(struct i915_sw_fence *fence);
 71
 72int i915_sw_fence_await_sw_fence(struct i915_sw_fence *fence,
 73				 struct i915_sw_fence *after,
 74				 wait_queue_entry_t *wq);
 75int i915_sw_fence_await_sw_fence_gfp(struct i915_sw_fence *fence,
 76				     struct i915_sw_fence *after,
 77				     gfp_t gfp);
 78
 79struct i915_sw_dma_fence_cb {
 80	struct dma_fence_cb base;
 81	struct i915_sw_fence *fence;
 82};
 83
 84int __i915_sw_fence_await_dma_fence(struct i915_sw_fence *fence,
 85				    struct dma_fence *dma,
 86				    struct i915_sw_dma_fence_cb *cb);
 87int i915_sw_fence_await_dma_fence(struct i915_sw_fence *fence,
 88				  struct dma_fence *dma,
 89				  unsigned long timeout,
 90				  gfp_t gfp);
 91
 92int i915_sw_fence_await_reservation(struct i915_sw_fence *fence,
 93				    struct dma_resv *resv,
 94				    bool write,
 95				    unsigned long timeout,
 96				    gfp_t gfp);
 97
 98bool i915_sw_fence_await(struct i915_sw_fence *fence);
 99void i915_sw_fence_complete(struct i915_sw_fence *fence);
100
101static inline bool i915_sw_fence_signaled(const struct i915_sw_fence *fence)
102{
103	return atomic_read(&fence->pending) <= 0;
104}
105
106static inline bool i915_sw_fence_done(const struct i915_sw_fence *fence)
107{
108	return atomic_read(&fence->pending) < 0;
109}
110
111static inline void i915_sw_fence_wait(struct i915_sw_fence *fence)
112{
113	wait_event(fence->wait, i915_sw_fence_done(fence));
114}
115
116static inline void
117i915_sw_fence_set_error_once(struct i915_sw_fence *fence, int error)
118{
119	if (unlikely(error))
120		cmpxchg(&fence->error, 0, error);
121}
122
123#endif /* _I915_SW_FENCE_H_ */