fimc-is: Fix/add vidioc_querycap for several video nodes
[platform/kernel/linux-exynos.git] / include / linux / reservation.h
1 /*
2  * Header file for reservations for dma-buf and ttm
3  *
4  * Copyright(C) 2011 Linaro Limited. All rights reserved.
5  * Copyright (C) 2012-2013 Canonical Ltd
6  * Copyright (C) 2012 Texas Instruments
7  *
8  * Authors:
9  * Rob Clark <robdclark@gmail.com>
10  * Maarten Lankhorst <maarten.lankhorst@canonical.com>
11  * Thomas Hellstrom <thellstrom-at-vmware-dot-com>
12  *
13  * Based on bo.c which bears the following copyright notice,
14  * but is dual licensed:
15  *
16  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
17  * All Rights Reserved.
18  *
19  * Permission is hereby granted, free of charge, to any person obtaining a
20  * copy of this software and associated documentation files (the
21  * "Software"), to deal in the Software without restriction, including
22  * without limitation the rights to use, copy, modify, merge, publish,
23  * distribute, sub license, and/or sell copies of the Software, and to
24  * permit persons to whom the Software is furnished to do so, subject to
25  * the following conditions:
26  *
27  * The above copyright notice and this permission notice (including the
28  * next paragraph) shall be included in all copies or substantial portions
29  * of the Software.
30  *
31  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
32  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
33  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
34  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
35  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
36  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
37  * USE OR OTHER DEALINGS IN THE SOFTWARE.
38  */
39 #ifndef _LINUX_RESERVATION_H
40 #define _LINUX_RESERVATION_H
41
42 #include <linux/ww_mutex.h>
43 #include <linux/dma-fence.h>
44 #include <linux/slab.h>
45 #include <linux/seqlock.h>
46 #include <linux/rcupdate.h>
47
48 extern struct ww_class reservation_ww_class;
49 extern struct lock_class_key reservation_seqcount_class;
50 extern const char reservation_seqcount_string[];
51
52 /**
53  * struct reservation_object_list - a list of shared fences
54  * @rcu: for internal use
55  * @shared_count: table of shared fences
56  * @shared_max: for growing shared fence table
57  * @shared: shared fence table
58  */
59 struct reservation_object_list {
60         struct rcu_head rcu;
61         u32 shared_count, shared_max;
62         struct dma_fence __rcu *shared[];
63 };
64
65 /**
66  * struct reservation_object - a reservation object manages fences for a buffer
67  * @lock: update side lock
68  * @seq: sequence count for managing RCU read-side synchronization
69  * @fence_excl: the exclusive fence, if there is one currently
70  * @fence: list of current shared fences
71  * @staged: staged copy of shared fences for RCU updates
72  */
73 struct reservation_object {
74         struct ww_mutex lock;
75         seqcount_t seq;
76
77         struct dma_fence __rcu *fence_excl;
78         struct reservation_object_list __rcu *fence;
79         struct reservation_object_list *staged;
80 };
81
82 #define reservation_object_held(obj) lockdep_is_held(&(obj)->lock.base)
83 #define reservation_object_assert_held(obj) \
84         lockdep_assert_held(&(obj)->lock.base)
85
86 /**
87  * reservation_object_init - initialize a reservation object
88  * @obj: the reservation object
89  */
90 static inline void
91 reservation_object_init(struct reservation_object *obj)
92 {
93         ww_mutex_init(&obj->lock, &reservation_ww_class);
94
95         __seqcount_init(&obj->seq, reservation_seqcount_string, &reservation_seqcount_class);
96         RCU_INIT_POINTER(obj->fence, NULL);
97         RCU_INIT_POINTER(obj->fence_excl, NULL);
98         obj->staged = NULL;
99 }
100
101 /**
102  * reservation_object_fini - destroys a reservation object
103  * @obj: the reservation object
104  */
105 static inline void
106 reservation_object_fini(struct reservation_object *obj)
107 {
108         int i;
109         struct reservation_object_list *fobj;
110         struct dma_fence *excl;
111
112         /*
113          * This object should be dead and all references must have
114          * been released to it, so no need to be protected with rcu.
115          */
116         excl = rcu_dereference_protected(obj->fence_excl, 1);
117         if (excl)
118                 dma_fence_put(excl);
119
120         fobj = rcu_dereference_protected(obj->fence, 1);
121         if (fobj) {
122                 for (i = 0; i < fobj->shared_count; ++i)
123                         dma_fence_put(rcu_dereference_protected(fobj->shared[i], 1));
124
125                 kfree(fobj);
126         }
127         kfree(obj->staged);
128
129         ww_mutex_destroy(&obj->lock);
130 }
131
132 /**
133  * reservation_object_get_list - get the reservation object's
134  * shared fence list, with update-side lock held
135  * @obj: the reservation object
136  *
137  * Returns the shared fence list.  Does NOT take references to
138  * the fence.  The obj->lock must be held.
139  */
140 static inline struct reservation_object_list *
141 reservation_object_get_list(struct reservation_object *obj)
142 {
143         return rcu_dereference_protected(obj->fence,
144                                          reservation_object_held(obj));
145 }
146
147 /**
148  * reservation_object_lock - lock the reservation object
149  * @obj: the reservation object
150  * @ctx: the locking context
151  *
152  * Locks the reservation object for exclusive access and modification. Note,
153  * that the lock is only against other writers, readers will run concurrently
154  * with a writer under RCU. The seqlock is used to notify readers if they
155  * overlap with a writer.
156  *
157  * As the reservation object may be locked by multiple parties in an
158  * undefined order, a #ww_acquire_ctx is passed to unwind if a cycle
159  * is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation
160  * object may be locked by itself by passing NULL as @ctx.
161  */
162 static inline int
163 reservation_object_lock(struct reservation_object *obj,
164                         struct ww_acquire_ctx *ctx)
165 {
166         return ww_mutex_lock(&obj->lock, ctx);
167 }
168
169 /**
170  * reservation_object_trylock - trylock the reservation object
171  * @obj: the reservation object
172  *
173  * Tries to lock the reservation object for exclusive access and modification.
174  * Note, that the lock is only against other writers, readers will run
175  * concurrently with a writer under RCU. The seqlock is used to notify readers
176  * if they overlap with a writer.
177  *
178  * Also note that since no context is provided, no deadlock protection is
179  * possible.
180  *
181  * Returns true if the lock was acquired, false otherwise.
182  */
183 static inline bool __must_check
184 reservation_object_trylock(struct reservation_object *obj)
185 {
186         return ww_mutex_trylock(&obj->lock);
187 }
188
189 /**
190  * reservation_object_unlock - unlock the reservation object
191  * @obj: the reservation object
192  *
193  * Unlocks the reservation object following exclusive access.
194  */
195 static inline void
196 reservation_object_unlock(struct reservation_object *obj)
197 {
198         ww_mutex_unlock(&obj->lock);
199 }
200
201 /**
202  * reservation_object_get_excl - get the reservation object's
203  * exclusive fence, with update-side lock held
204  * @obj: the reservation object
205  *
206  * Returns the exclusive fence (if any).  Does NOT take a
207  * reference.  The obj->lock must be held.
208  *
209  * RETURNS
210  * The exclusive fence or NULL
211  */
212 static inline struct dma_fence *
213 reservation_object_get_excl(struct reservation_object *obj)
214 {
215         return rcu_dereference_protected(obj->fence_excl,
216                                          reservation_object_held(obj));
217 }
218
219 /**
220  * reservation_object_get_excl_rcu - get the reservation object's
221  * exclusive fence, without lock held.
222  * @obj: the reservation object
223  *
224  * If there is an exclusive fence, this atomically increments it's
225  * reference count and returns it.
226  *
227  * RETURNS
228  * The exclusive fence or NULL if none
229  */
230 static inline struct dma_fence *
231 reservation_object_get_excl_rcu(struct reservation_object *obj)
232 {
233         struct dma_fence *fence;
234
235         if (!rcu_access_pointer(obj->fence_excl))
236                 return NULL;
237
238         rcu_read_lock();
239         fence = dma_fence_get_rcu_safe(&obj->fence_excl);
240         rcu_read_unlock();
241
242         return fence;
243 }
244
245 int reservation_object_reserve_shared(struct reservation_object *obj);
246 void reservation_object_add_shared_fence(struct reservation_object *obj,
247                                          struct dma_fence *fence);
248
249 void reservation_object_add_excl_fence(struct reservation_object *obj,
250                                        struct dma_fence *fence);
251
252 int reservation_object_get_fences_rcu(struct reservation_object *obj,
253                                       struct dma_fence **pfence_excl,
254                                       unsigned *pshared_count,
255                                       struct dma_fence ***pshared);
256
257 int reservation_object_copy_fences(struct reservation_object *dst,
258                                    struct reservation_object *src);
259
260 long reservation_object_wait_timeout_rcu(struct reservation_object *obj,
261                                          bool wait_all, bool intr,
262                                          unsigned long timeout);
263
264 bool reservation_object_test_signaled_rcu(struct reservation_object *obj,
265                                           bool test_all);
266
267 #endif /* _LINUX_RESERVATION_H */