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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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19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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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  * @new_sync_obj_arg: New sync_obj_arg for @bo, to be used once
43  * adding a new sync object.
44  * @usage           Indicates how @bo is used by the device.
45  * @reserved:       Indicates whether @bo has been reserved for validation.
46  * @removed:        Indicates whether @bo has been removed from lru lists.
47  * @put_count:      Number of outstanding references on bo::list_kref.
48  * @old_sync_obj:   Pointer to a sync object about to be unreferenced
49  * @old_sync_obj_read: Pointer to a read sync object about to be unreferenced.
50  * @old_sync_obj_write: Pointer to a write sync object about to be unreferenced.
51  */
52 
53 struct ttm_validate_buffer {
54 	struct list_head head;
55 	struct ttm_buffer_object *bo;
56 	void *new_sync_obj_arg;
57 	enum ttm_buffer_usage usage;
58 	bool reserved;
59 	bool removed;
60 	int put_count;
61 	void *old_sync_obj;
62 	void *old_sync_obj_read;
63 	void *old_sync_obj_write;
64 };
65 
66 /**
67  * function ttm_eu_backoff_reservation
68  *
69  * @list:     thread private list of ttm_validate_buffer structs.
70  *
71  * Undoes all buffer validation reservations for bos pointed to by
72  * the list entries.
73  */
74 
75 extern void ttm_eu_backoff_reservation(struct list_head *list);
76 
77 /**
78  * function ttm_eu_reserve_buffers
79  *
80  * @list:    thread private list of ttm_validate_buffer structs.
81  *
82  * Tries to reserve bos pointed to by the list entries for validation.
83  * If the function returns 0, all buffers are marked as "unfenced",
84  * taken off the lru lists and are not synced for write CPU usage.
85  *
86  * If the function detects a deadlock due to multiple threads trying to
87  * reserve the same buffers in reverse order, all threads except one will
88  * back off and retry. This function may sleep while waiting for
89  * CPU write reservations to be cleared, and for other threads to
90  * unreserve their buffers.
91  *
92  * This function may return -ERESTART or -EAGAIN if the calling process
93  * receives a signal while waiting. In that case, no buffers on the list
94  * will be reserved upon return.
95  *
96  * Buffers reserved by this function should be unreserved by
97  * a call to either ttm_eu_backoff_reservation() or
98  * ttm_eu_fence_buffer_objects() when command submission is complete or
99  * has failed.
100  */
101 
102 extern int ttm_eu_reserve_buffers(struct list_head *list);
103 
104 /**
105  * function ttm_eu_fence_buffer_objects.
106  *
107  * @list:        thread private list of ttm_validate_buffer structs.
108  * @sync_obj:    The new sync object for the buffers.
109  *
110  * This function should be called when command submission is complete, and
111  * it will add a new sync object to bos pointed to by entries on @list.
112  * It also unreserves all buffers, putting them on lru lists.
113  *
114  */
115 
116 extern void ttm_eu_fence_buffer_objects(struct list_head *list, void *sync_obj);
117 
118 #endif
119