1 /* $NetBSD: ttm_object.h,v 1.2 2021/12/18 23:45:45 riastradh Exp $ */
2
3 /**************************************************************************
4 *
5 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
6 * All Rights Reserved.
7 *
8 * Permission is hereby granted, free of charge, to any person obtaining a
9 * copy of this software and associated documentation files (the
10 * "Software"), to deal in the Software without restriction, including
11 * without limitation the rights to use, copy, modify, merge, publish,
12 * distribute, sub license, and/or sell copies of the Software, and to
13 * permit persons to whom the Software is furnished to do so, subject to
14 * the following conditions:
15 *
16 * The above copyright notice and this permission notice (including the
17 * next paragraph) shall be included in all copies or substantial portions
18 * of the Software.
19 *
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
23 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
24 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
25 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
26 * USE OR OTHER DEALINGS IN THE SOFTWARE.
27 *
28 **************************************************************************/
29 /*
30 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
31 */
32 /** @file ttm_object.h
33 *
34 * Base- and reference object implementation for the various
35 * ttm objects. Implements reference counting, minimal security checks
36 * and release on file close.
37 */
38
39 #ifndef _TTM_OBJECT_H_
40 #define _TTM_OBJECT_H_
41
42 #include <linux/dma-buf.h>
43 #include <linux/kref.h>
44 #include <linux/list.h>
45 #include <linux/rcupdate.h>
46
47 #include <drm/drm_hashtab.h>
48 #include <drm/ttm/ttm_memory.h>
49
50 /**
51 * enum ttm_ref_type
52 *
53 * Describes what type of reference a ref object holds.
54 *
55 * TTM_REF_USAGE is a simple refcount on a base object.
56 *
57 * TTM_REF_SYNCCPU_READ is a SYNCCPU_READ reference on a
58 * buffer object.
59 *
60 * TTM_REF_SYNCCPU_WRITE is a SYNCCPU_WRITE reference on a
61 * buffer object.
62 *
63 */
64
65 enum ttm_ref_type {
66 TTM_REF_USAGE,
67 TTM_REF_SYNCCPU_READ,
68 TTM_REF_SYNCCPU_WRITE,
69 TTM_REF_NUM
70 };
71
72 /**
73 * enum ttm_object_type
74 *
75 * One entry per ttm object type.
76 * Device-specific types should use the
77 * ttm_driver_typex types.
78 */
79
80 enum ttm_object_type {
81 ttm_fence_type,
82 ttm_buffer_type,
83 ttm_lock_type,
84 ttm_prime_type,
85 ttm_driver_type0 = 256,
86 ttm_driver_type1,
87 ttm_driver_type2,
88 ttm_driver_type3,
89 ttm_driver_type4,
90 ttm_driver_type5
91 };
92
93 struct ttm_object_file;
94 struct ttm_object_device;
95
96 /**
97 * struct ttm_base_object
98 *
99 * @hash: hash entry for the per-device object hash.
100 * @type: derived type this object is base class for.
101 * @shareable: Other ttm_object_files can access this object.
102 *
103 * @tfile: Pointer to ttm_object_file of the creator.
104 * NULL if the object was not created by a user request.
105 * (kernel object).
106 *
107 * @refcount: Number of references to this object, not
108 * including the hash entry. A reference to a base object can
109 * only be held by a ref object.
110 *
111 * @refcount_release: A function to be called when there are
112 * no more references to this object. This function should
113 * destroy the object (or make sure destruction eventually happens),
114 * and when it is called, the object has
115 * already been taken out of the per-device hash. The parameter
116 * "base" should be set to NULL by the function.
117 *
118 * @ref_obj_release: A function to be called when a reference object
119 * with another ttm_ref_type than TTM_REF_USAGE is deleted.
120 * This function may, for example, release a lock held by a user-space
121 * process.
122 *
123 * This struct is intended to be used as a base struct for objects that
124 * are visible to user-space. It provides a global name, race-safe
125 * access and refcounting, minimal access contol and hooks for unref actions.
126 */
127
128 struct ttm_base_object {
129 struct rcu_head rhead;
130 struct ttm_object_file *tfile;
131 struct kref refcount;
132 void (*refcount_release) (struct ttm_base_object **base);
133 void (*ref_obj_release) (struct ttm_base_object *base,
134 enum ttm_ref_type ref_type);
135 u32 handle;
136 enum ttm_object_type object_type;
137 u32 shareable;
138 };
139
140
141 /**
142 * struct ttm_prime_object - Modified base object that is prime-aware
143 *
144 * @base: struct ttm_base_object that we derive from
145 * @mutex: Mutex protecting the @dma_buf member.
146 * @size: Size of the dma_buf associated with this object
147 * @real_type: Type of the underlying object. Needed since we're setting
148 * the value of @base::object_type to ttm_prime_type
149 * @dma_buf: Non ref-coutned pointer to a struct dma_buf created from this
150 * object.
151 * @refcount_release: The underlying object's release method. Needed since
152 * we set @base::refcount_release to our own release method.
153 */
154
155 struct ttm_prime_object {
156 struct ttm_base_object base;
157 struct mutex mutex;
158 size_t size;
159 enum ttm_object_type real_type;
160 struct dma_buf *dma_buf;
161 void (*refcount_release) (struct ttm_base_object **);
162 };
163
164 /**
165 * ttm_base_object_init
166 *
167 * @tfile: Pointer to a struct ttm_object_file.
168 * @base: The struct ttm_base_object to initialize.
169 * @shareable: This object is shareable with other applcations.
170 * (different @tfile pointers.)
171 * @type: The object type.
172 * @refcount_release: See the struct ttm_base_object description.
173 * @ref_obj_release: See the struct ttm_base_object description.
174 *
175 * Initializes a struct ttm_base_object.
176 */
177
178 extern int ttm_base_object_init(struct ttm_object_file *tfile,
179 struct ttm_base_object *base,
180 bool shareable,
181 enum ttm_object_type type,
182 void (*refcount_release) (struct ttm_base_object
183 **),
184 void (*ref_obj_release) (struct ttm_base_object
185 *,
186 enum ttm_ref_type
187 ref_type));
188
189 /**
190 * ttm_base_object_lookup
191 *
192 * @tfile: Pointer to a struct ttm_object_file.
193 * @key: Hash key
194 *
195 * Looks up a struct ttm_base_object with the key @key.
196 */
197
198 extern struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file
199 *tfile, uint32_t key);
200
201 /**
202 * ttm_base_object_lookup_for_ref
203 *
204 * @tdev: Pointer to a struct ttm_object_device.
205 * @key: Hash key
206 *
207 * Looks up a struct ttm_base_object with the key @key.
208 * This function should only be used when the struct tfile associated with the
209 * caller doesn't yet have a reference to the base object.
210 */
211
212 extern struct ttm_base_object *
213 ttm_base_object_lookup_for_ref(struct ttm_object_device *tdev, uint32_t key);
214
215 /**
216 * ttm_base_object_unref
217 *
218 * @p_base: Pointer to a pointer referencing a struct ttm_base_object.
219 *
220 * Decrements the base object refcount and clears the pointer pointed to by
221 * p_base.
222 */
223
224 extern void ttm_base_object_unref(struct ttm_base_object **p_base);
225
226 /**
227 * ttm_ref_object_add.
228 *
229 * @tfile: A struct ttm_object_file representing the application owning the
230 * ref_object.
231 * @base: The base object to reference.
232 * @ref_type: The type of reference.
233 * @existed: Upon completion, indicates that an identical reference object
234 * already existed, and the refcount was upped on that object instead.
235 * @require_existed: Fail with -EPERM if an identical ref object didn't
236 * already exist.
237 *
238 * Checks that the base object is shareable and adds a ref object to it.
239 *
240 * Adding a ref object to a base object is basically like referencing the
241 * base object, but a user-space application holds the reference. When the
242 * file corresponding to @tfile is closed, all its reference objects are
243 * deleted. A reference object can have different types depending on what
244 * it's intended for. It can be refcounting to prevent object destruction,
245 * When user-space takes a lock, it can add a ref object to that lock to
246 * make sure the lock is released if the application dies. A ref object
247 * will hold a single reference on a base object.
248 */
249 extern int ttm_ref_object_add(struct ttm_object_file *tfile,
250 struct ttm_base_object *base,
251 enum ttm_ref_type ref_type, bool *existed,
252 bool require_existed);
253
254 extern bool ttm_ref_object_exists(struct ttm_object_file *tfile,
255 struct ttm_base_object *base);
256
257 /**
258 * ttm_ref_object_base_unref
259 *
260 * @key: Key representing the base object.
261 * @ref_type: Ref type of the ref object to be dereferenced.
262 *
263 * Unreference a ref object with type @ref_type
264 * on the base object identified by @key. If there are no duplicate
265 * references, the ref object will be destroyed and the base object
266 * will be unreferenced.
267 */
268 extern int ttm_ref_object_base_unref(struct ttm_object_file *tfile,
269 unsigned long key,
270 enum ttm_ref_type ref_type);
271
272 /**
273 * ttm_object_file_init - initialize a struct ttm_object file
274 *
275 * @tdev: A struct ttm_object device this file is initialized on.
276 * @hash_order: Order of the hash table used to hold the reference objects.
277 *
278 * This is typically called by the file_ops::open function.
279 */
280
281 extern struct ttm_object_file *ttm_object_file_init(struct ttm_object_device
282 *tdev,
283 unsigned int hash_order);
284
285 /**
286 * ttm_object_file_release - release data held by a ttm_object_file
287 *
288 * @p_tfile: Pointer to pointer to the ttm_object_file object to release.
289 * *p_tfile will be set to NULL by this function.
290 *
291 * Releases all data associated by a ttm_object_file.
292 * Typically called from file_ops::release. The caller must
293 * ensure that there are no concurrent users of tfile.
294 */
295
296 extern void ttm_object_file_release(struct ttm_object_file **p_tfile);
297
298 /**
299 * ttm_object device init - initialize a struct ttm_object_device
300 *
301 * @mem_glob: struct ttm_mem_global for memory accounting.
302 * @hash_order: Order of hash table used to hash the base objects.
303 * @ops: DMA buf ops for prime objects of this device.
304 *
305 * This function is typically called on device initialization to prepare
306 * data structures needed for ttm base and ref objects.
307 */
308
309 extern struct ttm_object_device *
310 ttm_object_device_init(struct ttm_mem_global *mem_glob,
311 unsigned int hash_order,
312 const struct dma_buf_ops *ops);
313
314 /**
315 * ttm_object_device_release - release data held by a ttm_object_device
316 *
317 * @p_tdev: Pointer to pointer to the ttm_object_device object to release.
318 * *p_tdev will be set to NULL by this function.
319 *
320 * Releases all data associated by a ttm_object_device.
321 * Typically called from driver::unload before the destruction of the
322 * device private data structure.
323 */
324
325 extern void ttm_object_device_release(struct ttm_object_device **p_tdev);
326
327 #define ttm_base_object_kfree(__object, __base)\
328 kfree_rcu(__object, __base.rhead)
329
330 extern int ttm_prime_object_init(struct ttm_object_file *tfile,
331 size_t size,
332 struct ttm_prime_object *prime,
333 bool shareable,
334 enum ttm_object_type type,
335 void (*refcount_release)
336 (struct ttm_base_object **),
337 void (*ref_obj_release)
338 (struct ttm_base_object *,
339 enum ttm_ref_type ref_type));
340
341 static inline enum ttm_object_type
ttm_base_object_type(struct ttm_base_object * base)342 ttm_base_object_type(struct ttm_base_object *base)
343 {
344 return (base->object_type == ttm_prime_type) ?
345 container_of(base, struct ttm_prime_object, base)->real_type :
346 base->object_type;
347 }
348 extern int ttm_prime_fd_to_handle(struct ttm_object_file *tfile,
349 int fd, u32 *handle);
350 extern int ttm_prime_handle_to_fd(struct ttm_object_file *tfile,
351 uint32_t handle, uint32_t flags,
352 int *prime_fd);
353
354 #define ttm_prime_object_kfree(__obj, __prime) \
355 kfree_rcu(__obj, __prime.base.rhead)
356
357 /*
358 * Extra memory required by the base object's idr storage, which is allocated
359 * separately from the base object itself. We estimate an on-average 128 bytes
360 * per idr.
361 */
362 #define TTM_OBJ_EXTRA_SIZE 128
363
364 struct ttm_base_object *
365 ttm_base_object_noref_lookup(struct ttm_object_file *tfile, uint32_t key);
366
367 /**
368 * ttm_base_object_noref_release - release a base object pointer looked up
369 * without reference
370 *
371 * Releases a base object pointer looked up with ttm_base_object_noref_lookup().
372 */
ttm_base_object_noref_release(void)373 static inline void ttm_base_object_noref_release(void)
374 {
375 __acquire(RCU);
376 rcu_read_unlock();
377 }
378 #endif
379