xref: /linux/include/drm/ttm/ttm_execbuf_util.h (revision 0e9b70c1e3623fa110fb6be553e644524228ef60)
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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 <linux/list.h>
35 
36 struct ww_acquire_ctx;
37 struct dma_fence;
38 struct ttm_buffer_object;
39 
40 /**
41  * struct ttm_validate_buffer
42  *
43  * @head:           list head for thread-private list.
44  * @bo:             refcounted buffer object pointer.
45  * @num_shared:     How many shared fences we want to add.
46  */
47 
48 struct ttm_validate_buffer {
49 	struct list_head head;
50 	struct ttm_buffer_object *bo;
51 	unsigned int num_shared;
52 };
53 
54 /**
55  * function ttm_eu_backoff_reservation
56  *
57  * @ticket:   ww_acquire_ctx from reserve call
58  * @list:     thread private list of ttm_validate_buffer structs.
59  *
60  * Undoes all buffer validation reservations for bos pointed to by
61  * the list entries.
62  */
63 void ttm_eu_backoff_reservation(struct ww_acquire_ctx *ticket,
64 				struct list_head *list);
65 
66 /**
67  * function ttm_eu_reserve_buffers
68  *
69  * @ticket:  [out] ww_acquire_ctx filled in by call, or NULL if only
70  *           non-blocking reserves should be tried.
71  * @list:    thread private list of ttm_validate_buffer structs.
72  * @intr:    should the wait be interruptible
73  * @dups:    [out] optional list of duplicates.
74  * @del_lru: true if BOs should be removed from the LRU.
75  *
76  * Tries to reserve bos pointed to by the list entries for validation.
77  * If the function returns 0, all buffers are marked as "unfenced",
78  * taken off the lru lists and are not synced for write CPU usage.
79  *
80  * If the function detects a deadlock due to multiple threads trying to
81  * reserve the same buffers in reverse order, all threads except one will
82  * back off and retry. This function may sleep while waiting for
83  * CPU write reservations to be cleared, and for other threads to
84  * unreserve their buffers.
85  *
86  * If intr is set to true, this function may return -ERESTARTSYS if the
87  * calling process receives a signal while waiting. In that case, no
88  * buffers on the list will be reserved upon return.
89  *
90  * If dups is non NULL all buffers already reserved by the current thread
91  * (e.g. duplicates) are added to this list, otherwise -EALREADY is returned
92  * on the first already reserved buffer and all buffers from the list are
93  * unreserved again.
94  *
95  * Buffers reserved by this function should be unreserved by
96  * a call to either ttm_eu_backoff_reservation() or
97  * ttm_eu_fence_buffer_objects() when command submission is complete or
98  * has failed.
99  */
100 int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
101 			   struct list_head *list, bool intr,
102 			   struct list_head *dups);
103 
104 /**
105  * function ttm_eu_fence_buffer_objects.
106  *
107  * @ticket:      ww_acquire_ctx from reserve call
108  * @list:        thread private list of ttm_validate_buffer structs.
109  * @fence:       The new exclusive fence for the buffers.
110  *
111  * This function should be called when command submission is complete, and
112  * it will add a new sync object to bos pointed to by entries on @list.
113  * It also unreserves all buffers, putting them on lru lists.
114  *
115  */
116 void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket,
117 				 struct list_head *list,
118 				 struct dma_fence *fence);
119 
120 #endif
121