xref: /openbmc/linux/include/drm/drm_exec.h (revision d20b484c)
1 /* SPDX-License-Identifier: GPL-2.0 OR MIT */
2 
3 #ifndef __DRM_EXEC_H__
4 #define __DRM_EXEC_H__
5 
6 #include <linux/compiler.h>
7 #include <linux/ww_mutex.h>
8 
9 #define DRM_EXEC_INTERRUPTIBLE_WAIT	BIT(0)
10 #define DRM_EXEC_IGNORE_DUPLICATES	BIT(1)
11 
12 struct drm_gem_object;
13 
14 /**
15  * struct drm_exec - Execution context
16  */
17 struct drm_exec {
18 	/**
19 	 * @flags: Flags to control locking behavior
20 	 */
21 	uint32_t		flags;
22 
23 	/**
24 	 * @ticket: WW ticket used for acquiring locks
25 	 */
26 	struct ww_acquire_ctx	ticket;
27 
28 	/**
29 	 * @num_objects: number of objects locked
30 	 */
31 	unsigned int		num_objects;
32 
33 	/**
34 	 * @max_objects: maximum objects in array
35 	 */
36 	unsigned int		max_objects;
37 
38 	/**
39 	 * @objects: array of the locked objects
40 	 */
41 	struct drm_gem_object	**objects;
42 
43 	/**
44 	 * @contended: contended GEM object we backed off for
45 	 */
46 	struct drm_gem_object	*contended;
47 
48 	/**
49 	 * @prelocked: already locked GEM object due to contention
50 	 */
51 	struct drm_gem_object *prelocked;
52 };
53 
54 /**
55  * drm_exec_obj() - Return the object for a give drm_exec index
56  * @exec: Pointer to the drm_exec context
57  * @index: The index.
58  *
59  * Return: Pointer to the locked object corresponding to @index if
60  * index is within the number of locked objects. NULL otherwise.
61  */
62 static inline struct drm_gem_object *
drm_exec_obj(struct drm_exec * exec,unsigned long index)63 drm_exec_obj(struct drm_exec *exec, unsigned long index)
64 {
65 	return index < exec->num_objects ? exec->objects[index] : NULL;
66 }
67 
68 /**
69  * drm_exec_for_each_locked_object - iterate over all the locked objects
70  * @exec: drm_exec object
71  * @index: unsigned long index for the iteration
72  * @obj: the current GEM object
73  *
74  * Iterate over all the locked GEM objects inside the drm_exec object.
75  */
76 #define drm_exec_for_each_locked_object(exec, index, obj)		\
77 	for ((index) = 0; ((obj) = drm_exec_obj(exec, index)); ++(index))
78 
79 /**
80  * drm_exec_for_each_locked_object_reverse - iterate over all the locked
81  * objects in reverse locking order
82  * @exec: drm_exec object
83  * @index: unsigned long index for the iteration
84  * @obj: the current GEM object
85  *
86  * Iterate over all the locked GEM objects inside the drm_exec object in
87  * reverse locking order. Note that @index may go below zero and wrap,
88  * but that will be caught by drm_exec_obj(), returning a NULL object.
89  */
90 #define drm_exec_for_each_locked_object_reverse(exec, index, obj)	\
91 	for ((index) = (exec)->num_objects - 1;				\
92 	     ((obj) = drm_exec_obj(exec, index)); --(index))
93 
94 /**
95  * drm_exec_until_all_locked - loop until all GEM objects are locked
96  * @exec: drm_exec object
97  *
98  * Core functionality of the drm_exec object. Loops until all GEM objects are
99  * locked and no more contention exists. At the beginning of the loop it is
100  * guaranteed that no GEM object is locked.
101  *
102  * Since labels can't be defined local to the loops body we use a jump pointer
103  * to make sure that the retry is only used from within the loops body.
104  */
105 #define drm_exec_until_all_locked(exec)					\
106 __PASTE(__drm_exec_, __LINE__):						\
107 	for (void *__drm_exec_retry_ptr; ({				\
108 		__drm_exec_retry_ptr = &&__PASTE(__drm_exec_, __LINE__);\
109 		(void)__drm_exec_retry_ptr;				\
110 		drm_exec_cleanup(exec);					\
111 	});)
112 
113 /**
114  * drm_exec_retry_on_contention - restart the loop to grap all locks
115  * @exec: drm_exec object
116  *
117  * Control flow helper to continue when a contention was detected and we need to
118  * clean up and re-start the loop to prepare all GEM objects.
119  */
120 #define drm_exec_retry_on_contention(exec)			\
121 	do {							\
122 		if (unlikely(drm_exec_is_contended(exec)))	\
123 			goto *__drm_exec_retry_ptr;		\
124 	} while (0)
125 
126 /**
127  * drm_exec_is_contended - check for contention
128  * @exec: drm_exec object
129  *
130  * Returns true if the drm_exec object has run into some contention while
131  * locking a GEM object and needs to clean up.
132  */
drm_exec_is_contended(struct drm_exec * exec)133 static inline bool drm_exec_is_contended(struct drm_exec *exec)
134 {
135 	return !!exec->contended;
136 }
137 
138 void drm_exec_init(struct drm_exec *exec, uint32_t flags);
139 void drm_exec_fini(struct drm_exec *exec);
140 bool drm_exec_cleanup(struct drm_exec *exec);
141 int drm_exec_lock_obj(struct drm_exec *exec, struct drm_gem_object *obj);
142 void drm_exec_unlock_obj(struct drm_exec *exec, struct drm_gem_object *obj);
143 int drm_exec_prepare_obj(struct drm_exec *exec, struct drm_gem_object *obj,
144 			 unsigned int num_fences);
145 int drm_exec_prepare_array(struct drm_exec *exec,
146 			   struct drm_gem_object **objects,
147 			   unsigned int num_objects,
148 			   unsigned int num_fences);
149 
150 #endif
151