xref: /freebsd/sys/dev/drm2/ttm/ttm_execbuf_util.h (revision f39bffc62c1395bde25d152c7f68fdf7cbaab414)
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27 /*
28  * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
29  */
30 /* $FreeBSD$ */
31 
32 #ifndef _TTM_EXECBUF_UTIL_H_
33 #define _TTM_EXECBUF_UTIL_H_
34 
35 #include <dev/drm2/ttm/ttm_bo_api.h>
36 
37 /**
38  * struct ttm_validate_buffer
39  *
40  * @head:           list head for thread-private list.
41  * @bo:             refcounted buffer object pointer.
42  * @reserved:       Indicates whether @bo has been reserved for validation.
43  * @removed:        Indicates whether @bo has been removed from lru lists.
44  * @put_count:      Number of outstanding references on bo::list_kref.
45  * @old_sync_obj:   Pointer to a sync object about to be unreferenced
46  */
47 
48 struct ttm_validate_buffer {
49 	struct list_head head;
50 	struct ttm_buffer_object *bo;
51 	bool reserved;
52 	bool removed;
53 	int put_count;
54 	void *old_sync_obj;
55 };
56 
57 /**
58  * function ttm_eu_backoff_reservation
59  *
60  * @list:     thread private list of ttm_validate_buffer structs.
61  *
62  * Undoes all buffer validation reservations for bos pointed to by
63  * the list entries.
64  */
65 
66 extern void ttm_eu_backoff_reservation(struct list_head *list);
67 
68 /**
69  * function ttm_eu_reserve_buffers
70  *
71  * @list:    thread private list of ttm_validate_buffer structs.
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  * This function may return -ERESTART or -EAGAIN if the calling process
84  * receives a signal while waiting. In that case, no buffers on the list
85  * will be reserved upon return.
86  *
87  * Buffers reserved by this function should be unreserved by
88  * a call to either ttm_eu_backoff_reservation() or
89  * ttm_eu_fence_buffer_objects() when command submission is complete or
90  * has failed.
91  */
92 
93 extern int ttm_eu_reserve_buffers(struct list_head *list);
94 
95 /**
96  * function ttm_eu_fence_buffer_objects.
97  *
98  * @list:        thread private list of ttm_validate_buffer structs.
99  * @sync_obj:    The new sync object for the buffers.
100  *
101  * This function should be called when command submission is complete, and
102  * it will add a new sync object to bos pointed to by entries on @list.
103  * It also unreserves all buffers, putting them on lru lists.
104  *
105  */
106 
107 extern void ttm_eu_fence_buffer_objects(struct list_head *list, void *sync_obj);
108 
109 #endif
110