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