1 /**************************************************************************
2  *
3  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
4  * All Rights Reserved.
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6  * Permission is hereby granted, free of charge, to any person obtaining a
7  * copy of this software and associated documentation files (the
8  * "Software"), to deal in the Software without restriction, including
9  * without limitation the rights to use, copy, modify, merge, publish,
10  * distribute, sub license, and/or sell copies of the Software, and to
11  * permit persons to whom the Software is furnished to do so, subject to
12  * the following conditions:
13  *
14  * The above copyright notice and this permission notice (including the
15  * next paragraph) shall be included in all copies or substantial portions
16  * of the Software.
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26  **************************************************************************/
27 /*
28  * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
29  */
30 
31 #ifndef _TTM_EXECBUF_UTIL_H_
32 #define _TTM_EXECBUF_UTIL_H_
33 
34 #include <ttm/ttm_bo_api.h>
35 #include <linux/list.h>
36 
37 /**
38  * struct ttm_validate_buffer
39  *
40  * @head:           list head for thread-private list.
41  * @bo:             refcounted buffer object pointer.
42  * @shared:         should the fence be added shared?
43  */
44 
45 struct ttm_validate_buffer {
46 	struct list_head head;
47 	struct ttm_buffer_object *bo;
48 	bool shared;
49 };
50 
51 /**
52  * function ttm_eu_backoff_reservation
53  *
54  * @ticket:   ww_acquire_ctx from reserve call
55  * @list:     thread private list of ttm_validate_buffer structs.
56  *
57  * Undoes all buffer validation reservations for bos pointed to by
58  * the list entries.
59  */
60 
61 extern void ttm_eu_backoff_reservation(struct ww_acquire_ctx *ticket,
62 				       struct list_head *list);
63 
64 /**
65  * function ttm_eu_reserve_buffers
66  *
67  * @ticket:  [out] ww_acquire_ctx filled in by call, or NULL if only
68  *           non-blocking reserves should be tried.
69  * @list:    thread private list of ttm_validate_buffer structs.
70  * @intr:    should the wait be interruptible
71  * @dups:    [out] optional list of duplicates.
72  *
73  * Tries to reserve bos pointed to by the list entries for validation.
74  * If the function returns 0, all buffers are marked as "unfenced",
75  * taken off the lru lists and are not synced for write CPU usage.
76  *
77  * If the function detects a deadlock due to multiple threads trying to
78  * reserve the same buffers in reverse order, all threads except one will
79  * back off and retry. This function may sleep while waiting for
80  * CPU write reservations to be cleared, and for other threads to
81  * unreserve their buffers.
82  *
83  * If intr is set to true, this function may return -ERESTARTSYS if the
84  * calling process receives a signal while waiting. In that case, no
85  * buffers on the list will be reserved upon return.
86  *
87  * If dups is non NULL all buffers already reserved by the current thread
88  * (e.g. duplicates) are added to this list, otherwise -EALREADY is returned
89  * on the first already reserved buffer and all buffers from the list are
90  * unreserved again.
91  *
92  * Buffers reserved by this function should be unreserved by
93  * a call to either ttm_eu_backoff_reservation() or
94  * ttm_eu_fence_buffer_objects() when command submission is complete or
95  * has failed.
96  */
97 
98 extern int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
99 				  struct list_head *list, bool intr,
100 				  struct list_head *dups);
101 
102 /**
103  * function ttm_eu_fence_buffer_objects.
104  *
105  * @ticket:      ww_acquire_ctx from reserve call
106  * @list:        thread private list of ttm_validate_buffer structs.
107  * @fence:       The new exclusive fence for the buffers.
108  *
109  * This function should be called when command submission is complete, and
110  * it will add a new sync object to bos pointed to by entries on @list.
111  * It also unreserves all buffers, putting them on lru lists.
112  *
113  */
114 
115 extern void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket,
116 					struct list_head *list,
117 					struct fence *fence);
118 
119 #endif
120