1 /**************************************************************************
2 *
3 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
4 * All Rights Reserved.
5 *
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.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
21 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
24 * USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27 /*
28 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
29 */
30 /** @file ttm_object.h
31 *
32 * Base- and reference object implementation for the various
33 * ttm objects. Implements reference counting, minimal security checks
34 * and release on file close.
35 */
36
37 #ifndef _TTM_OBJECT_H_
38 #define _TTM_OBJECT_H_
39
40 #include <linux/dma-buf.h>
41 #include <linux/kref.h>
42 #include <linux/list.h>
43 #include <linux/rcupdate.h>
44
45 #include <drm/drm_hashtab.h>
46
47 #include "ttm_memory.h"
48
49 /**
50 * enum ttm_ref_type
51 *
52 * Describes what type of reference a ref object holds.
53 *
54 * TTM_REF_USAGE is a simple refcount on a base object.
55 *
56 * TTM_REF_SYNCCPU_READ is a SYNCCPU_READ reference on a
57 * buffer object.
58 *
59 * TTM_REF_SYNCCPU_WRITE is a SYNCCPU_WRITE reference on a
60 * buffer object.
61 *
62 */
63
64 enum ttm_ref_type {
65 TTM_REF_USAGE,
66 TTM_REF_SYNCCPU_READ,
67 TTM_REF_SYNCCPU_WRITE,
68 TTM_REF_NUM
69 };
70
71 /**
72 * enum ttm_object_type
73 *
74 * One entry per ttm object type.
75 * Device-specific types should use the
76 * ttm_driver_typex types.
77 */
78
79 enum ttm_object_type {
80 ttm_fence_type,
81 ttm_buffer_type,
82 ttm_lock_type,
83 ttm_prime_type,
84 ttm_driver_type0 = 256,
85 ttm_driver_type1,
86 ttm_driver_type2,
87 ttm_driver_type3,
88 ttm_driver_type4,
89 ttm_driver_type5
90 };
91
92 struct ttm_object_file;
93 struct ttm_object_device;
94
95 /**
96 * struct ttm_base_object
97 *
98 * @hash: hash entry for the per-device object hash.
99 * @type: derived type this object is base class for.
100 * @shareable: Other ttm_object_files can access this object.
101 *
102 * @tfile: Pointer to ttm_object_file of the creator.
103 * NULL if the object was not created by a user request.
104 * (kernel object).
105 *
106 * @refcount: Number of references to this object, not
107 * including the hash entry. A reference to a base object can
108 * only be held by a ref object.
109 *
110 * @refcount_release: A function to be called when there are
111 * no more references to this object. This function should
112 * destroy the object (or make sure destruction eventually happens),
113 * and when it is called, the object has
114 * already been taken out of the per-device hash. The parameter
115 * "base" should be set to NULL by the function.
116 *
117 * @ref_obj_release: A function to be called when a reference object
118 * with another ttm_ref_type than TTM_REF_USAGE is deleted.
119 * This function may, for example, release a lock held by a user-space
120 * process.
121 *
122 * This struct is intended to be used as a base struct for objects that
123 * are visible to user-space. It provides a global name, race-safe
124 * access and refcounting, minimal access contol and hooks for unref actions.
125 */
126
127 struct ttm_base_object {
128 struct rcu_head rhead;
129 struct ttm_object_file *tfile;
130 struct kref refcount;
131 void (*refcount_release) (struct ttm_base_object **base);
132 void (*ref_obj_release) (struct ttm_base_object *base,
133 enum ttm_ref_type ref_type);
134 u32 handle;
135 enum ttm_object_type object_type;
136 u32 shareable;
137 };
138
139
140 /**
141 * struct ttm_prime_object - Modified base object that is prime-aware
142 *
143 * @base: struct ttm_base_object that we derive from
144 * @mutex: Mutex protecting the @dma_buf member.
145 * @size: Size of the dma_buf associated with this object
146 * @real_type: Type of the underlying object. Needed since we're setting
147 * the value of @base::object_type to ttm_prime_type
148 * @dma_buf: Non ref-coutned pointer to a struct dma_buf created from this
149 * object.
150 * @refcount_release: The underlying object's release method. Needed since
151 * we set @base::refcount_release to our own release method.
152 */
153
154 struct ttm_prime_object {
155 struct ttm_base_object base;
156 struct mutex mutex;
157 size_t size;
158 enum ttm_object_type real_type;
159 struct dma_buf *dma_buf;
160 void (*refcount_release) (struct ttm_base_object **);
161 };
162
163 /**
164 * ttm_base_object_init
165 *
166 * @tfile: Pointer to a struct ttm_object_file.
167 * @base: The struct ttm_base_object to initialize.
168 * @shareable: This object is shareable with other applcations.
169 * (different @tfile pointers.)
170 * @type: The object type.
171 * @refcount_release: See the struct ttm_base_object description.
172 * @ref_obj_release: See the struct ttm_base_object description.
173 *
174 * Initializes a struct ttm_base_object.
175 */
176
177 extern int ttm_base_object_init(struct ttm_object_file *tfile,
178 struct ttm_base_object *base,
179 bool shareable,
180 enum ttm_object_type type,
181 void (*refcount_release) (struct ttm_base_object
182 **),
183 void (*ref_obj_release) (struct ttm_base_object
184 *,
185 enum ttm_ref_type
186 ref_type));
187
188 /**
189 * ttm_base_object_lookup
190 *
191 * @tfile: Pointer to a struct ttm_object_file.
192 * @key: Hash key
193 *
194 * Looks up a struct ttm_base_object with the key @key.
195 */
196
197 extern struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file
198 *tfile, uint32_t key);
199
200 /**
201 * ttm_base_object_lookup_for_ref
202 *
203 * @tdev: Pointer to a struct ttm_object_device.
204 * @key: Hash key
205 *
206 * Looks up a struct ttm_base_object with the key @key.
207 * This function should only be used when the struct tfile associated with the
208 * caller doesn't yet have a reference to the base object.
209 */
210
211 extern struct ttm_base_object *
212 ttm_base_object_lookup_for_ref(struct ttm_object_device *tdev, uint32_t key);
213
214 /**
215 * ttm_base_object_unref
216 *
217 * @p_base: Pointer to a pointer referencing a struct ttm_base_object.
218 *
219 * Decrements the base object refcount and clears the pointer pointed to by
220 * p_base.
221 */
222
223 extern void ttm_base_object_unref(struct ttm_base_object **p_base);
224
225 /**
226 * ttm_ref_object_add.
227 *
228 * @tfile: A struct ttm_object_file representing the application owning the
229 * ref_object.
230 * @base: The base object to reference.
231 * @ref_type: The type of reference.
232 * @existed: Upon completion, indicates that an identical reference object
233 * already existed, and the refcount was upped on that object instead.
234 * @require_existed: Fail with -EPERM if an identical ref object didn't
235 * already exist.
236 *
237 * Checks that the base object is shareable and adds a ref object to it.
238 *
239 * Adding a ref object to a base object is basically like referencing the
240 * base object, but a user-space application holds the reference. When the
241 * file corresponding to @tfile is closed, all its reference objects are
242 * deleted. A reference object can have different types depending on what
243 * it's intended for. It can be refcounting to prevent object destruction,
244 * When user-space takes a lock, it can add a ref object to that lock to
245 * make sure the lock is released if the application dies. A ref object
246 * will hold a single reference on a base object.
247 */
248 extern int ttm_ref_object_add(struct ttm_object_file *tfile,
249 struct ttm_base_object *base,
250 enum ttm_ref_type ref_type, bool *existed,
251 bool require_existed);
252
253 extern bool ttm_ref_object_exists(struct ttm_object_file *tfile,
254 struct ttm_base_object *base);
255
256 /**
257 * ttm_ref_object_base_unref
258 *
259 * @key: Key representing the base object.
260 * @ref_type: Ref type of the ref object to be dereferenced.
261 *
262 * Unreference a ref object with type @ref_type
263 * on the base object identified by @key. If there are no duplicate
264 * references, the ref object will be destroyed and the base object
265 * will be unreferenced.
266 */
267 extern int ttm_ref_object_base_unref(struct ttm_object_file *tfile,
268 unsigned long key,
269 enum ttm_ref_type ref_type);
270
271 /**
272 * ttm_object_file_init - initialize a struct ttm_object file
273 *
274 * @tdev: A struct ttm_object device this file is initialized on.
275 * @hash_order: Order of the hash table used to hold the reference objects.
276 *
277 * This is typically called by the file_ops::open function.
278 */
279
280 extern struct ttm_object_file *ttm_object_file_init(struct ttm_object_device
281 *tdev,
282 unsigned int hash_order);
283
284 /**
285 * ttm_object_file_release - release data held by a ttm_object_file
286 *
287 * @p_tfile: Pointer to pointer to the ttm_object_file object to release.
288 * *p_tfile will be set to NULL by this function.
289 *
290 * Releases all data associated by a ttm_object_file.
291 * Typically called from file_ops::release. The caller must
292 * ensure that there are no concurrent users of tfile.
293 */
294
295 extern void ttm_object_file_release(struct ttm_object_file **p_tfile);
296
297 /**
298 * ttm_object device init - initialize a struct ttm_object_device
299 *
300 * @mem_glob: struct ttm_mem_global for memory accounting.
301 * @hash_order: Order of hash table used to hash the base objects.
302 * @ops: DMA buf ops for prime objects of this device.
303 *
304 * This function is typically called on device initialization to prepare
305 * data structures needed for ttm base and ref objects.
306 */
307
308 extern struct ttm_object_device *
309 ttm_object_device_init(struct ttm_mem_global *mem_glob,
310 unsigned int hash_order,
311 const struct dma_buf_ops *ops);
312
313 /**
314 * ttm_object_device_release - release data held by a ttm_object_device
315 *
316 * @p_tdev: Pointer to pointer to the ttm_object_device object to release.
317 * *p_tdev will be set to NULL by this function.
318 *
319 * Releases all data associated by a ttm_object_device.
320 * Typically called from driver::unload before the destruction of the
321 * device private data structure.
322 */
323
324 extern void ttm_object_device_release(struct ttm_object_device **p_tdev);
325
326 #define ttm_base_object_kfree(__object, __base)\
327 kfree_rcu(__object, __base.rhead)
328
329 extern int ttm_prime_object_init(struct ttm_object_file *tfile,
330 size_t size,
331 struct ttm_prime_object *prime,
332 bool shareable,
333 enum ttm_object_type type,
334 void (*refcount_release)
335 (struct ttm_base_object **),
336 void (*ref_obj_release)
337 (struct ttm_base_object *,
338 enum ttm_ref_type ref_type));
339
340 static inline enum ttm_object_type
ttm_base_object_type(struct ttm_base_object * base)341 ttm_base_object_type(struct ttm_base_object *base)
342 {
343 return (base->object_type == ttm_prime_type) ?
344 container_of(base, struct ttm_prime_object, base)->real_type :
345 base->object_type;
346 }
347 extern int ttm_prime_fd_to_handle(struct ttm_object_file *tfile,
348 int fd, u32 *handle);
349 extern int ttm_prime_handle_to_fd(struct ttm_object_file *tfile,
350 uint32_t handle, uint32_t flags,
351 int *prime_fd);
352
353 #define ttm_prime_object_kfree(__obj, __prime) \
354 kfree_rcu(__obj, __prime.base.rhead)
355
356 /*
357 * Extra memory required by the base object's idr storage, which is allocated
358 * separately from the base object itself. We estimate an on-average 128 bytes
359 * per idr.
360 */
361 #define TTM_OBJ_EXTRA_SIZE 128
362
363 struct ttm_base_object *
364 ttm_base_object_noref_lookup(struct ttm_object_file *tfile, uint32_t key);
365
366 /**
367 * ttm_base_object_noref_release - release a base object pointer looked up
368 * without reference
369 *
370 * Releases a base object pointer looked up with ttm_base_object_noref_lookup().
371 */
ttm_base_object_noref_release(void)372 static inline void ttm_base_object_noref_release(void)
373 {
374 __acquire(RCU);
375 rcu_read_unlock();
376 }
377 #endif
378