Merge branch 'drm-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied...
[linux-2.6.git] / drivers / gpu / drm / drm_mm.c
1 /**************************************************************************
2  *
3  * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., 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
29 /*
30  * Generic simple memory manager implementation. Intended to be used as a base
31  * class implementation for more advanced memory managers.
32  *
33  * Note that the algorithm used is quite simple and there might be substantial
34  * performance gains if a smarter free list is implemented. Currently it is just an
35  * unordered stack of free regions. This could easily be improved if an RB-tree
36  * is used instead. At least if we expect heavy fragmentation.
37  *
38  * Aligned allocations can also see improvement.
39  *
40  * Authors:
41  * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
42  */
43
44 #include "drmP.h"
45 #include "drm_mm.h"
46 #include <linux/slab.h>
47
48 #define MM_UNUSED_TARGET 4
49
50 unsigned long drm_mm_tail_space(struct drm_mm *mm)
51 {
52         struct list_head *tail_node;
53         struct drm_mm_node *entry;
54
55         tail_node = mm->ml_entry.prev;
56         entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
57         if (!entry->free)
58                 return 0;
59
60         return entry->size;
61 }
62
63 int drm_mm_remove_space_from_tail(struct drm_mm *mm, unsigned long size)
64 {
65         struct list_head *tail_node;
66         struct drm_mm_node *entry;
67
68         tail_node = mm->ml_entry.prev;
69         entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
70         if (!entry->free)
71                 return -ENOMEM;
72
73         if (entry->size <= size)
74                 return -ENOMEM;
75
76         entry->size -= size;
77         return 0;
78 }
79
80 static struct drm_mm_node *drm_mm_kmalloc(struct drm_mm *mm, int atomic)
81 {
82         struct drm_mm_node *child;
83
84         if (atomic)
85                 child = kmalloc(sizeof(*child), GFP_ATOMIC);
86         else
87                 child = kmalloc(sizeof(*child), GFP_KERNEL);
88
89         if (unlikely(child == NULL)) {
90                 spin_lock(&mm->unused_lock);
91                 if (list_empty(&mm->unused_nodes))
92                         child = NULL;
93                 else {
94                         child =
95                             list_entry(mm->unused_nodes.next,
96                                        struct drm_mm_node, fl_entry);
97                         list_del(&child->fl_entry);
98                         --mm->num_unused;
99                 }
100                 spin_unlock(&mm->unused_lock);
101         }
102         return child;
103 }
104
105 int drm_mm_pre_get(struct drm_mm *mm)
106 {
107         struct drm_mm_node *node;
108
109         spin_lock(&mm->unused_lock);
110         while (mm->num_unused < MM_UNUSED_TARGET) {
111                 spin_unlock(&mm->unused_lock);
112                 node = kmalloc(sizeof(*node), GFP_KERNEL);
113                 spin_lock(&mm->unused_lock);
114
115                 if (unlikely(node == NULL)) {
116                         int ret = (mm->num_unused < 2) ? -ENOMEM : 0;
117                         spin_unlock(&mm->unused_lock);
118                         return ret;
119                 }
120                 ++mm->num_unused;
121                 list_add_tail(&node->fl_entry, &mm->unused_nodes);
122         }
123         spin_unlock(&mm->unused_lock);
124         return 0;
125 }
126 EXPORT_SYMBOL(drm_mm_pre_get);
127
128 static int drm_mm_create_tail_node(struct drm_mm *mm,
129                                    unsigned long start,
130                                    unsigned long size, int atomic)
131 {
132         struct drm_mm_node *child;
133
134         child = drm_mm_kmalloc(mm, atomic);
135         if (unlikely(child == NULL))
136                 return -ENOMEM;
137
138         child->free = 1;
139         child->size = size;
140         child->start = start;
141         child->mm = mm;
142
143         list_add_tail(&child->ml_entry, &mm->ml_entry);
144         list_add_tail(&child->fl_entry, &mm->fl_entry);
145
146         return 0;
147 }
148
149 int drm_mm_add_space_to_tail(struct drm_mm *mm, unsigned long size, int atomic)
150 {
151         struct list_head *tail_node;
152         struct drm_mm_node *entry;
153
154         tail_node = mm->ml_entry.prev;
155         entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
156         if (!entry->free) {
157                 return drm_mm_create_tail_node(mm, entry->start + entry->size,
158                                                size, atomic);
159         }
160         entry->size += size;
161         return 0;
162 }
163
164 static struct drm_mm_node *drm_mm_split_at_start(struct drm_mm_node *parent,
165                                                  unsigned long size,
166                                                  int atomic)
167 {
168         struct drm_mm_node *child;
169
170         child = drm_mm_kmalloc(parent->mm, atomic);
171         if (unlikely(child == NULL))
172                 return NULL;
173
174         INIT_LIST_HEAD(&child->fl_entry);
175
176         child->free = 0;
177         child->size = size;
178         child->start = parent->start;
179         child->mm = parent->mm;
180
181         list_add_tail(&child->ml_entry, &parent->ml_entry);
182         INIT_LIST_HEAD(&child->fl_entry);
183
184         parent->size -= size;
185         parent->start += size;
186         return child;
187 }
188
189
190
191 struct drm_mm_node *drm_mm_get_block(struct drm_mm_node * parent,
192                                 unsigned long size, unsigned alignment)
193 {
194
195         struct drm_mm_node *align_splitoff = NULL;
196         struct drm_mm_node *child;
197         unsigned tmp = 0;
198
199         if (alignment)
200                 tmp = parent->start % alignment;
201
202         if (tmp) {
203                 align_splitoff =
204                     drm_mm_split_at_start(parent, alignment - tmp, 0);
205                 if (unlikely(align_splitoff == NULL))
206                         return NULL;
207         }
208
209         if (parent->size == size) {
210                 list_del_init(&parent->fl_entry);
211                 parent->free = 0;
212                 return parent;
213         } else {
214                 child = drm_mm_split_at_start(parent, size, 0);
215         }
216
217         if (align_splitoff)
218                 drm_mm_put_block(align_splitoff);
219
220         return child;
221 }
222
223 EXPORT_SYMBOL(drm_mm_get_block);
224
225 struct drm_mm_node *drm_mm_get_block_atomic(struct drm_mm_node *parent,
226                                             unsigned long size,
227                                             unsigned alignment)
228 {
229
230         struct drm_mm_node *align_splitoff = NULL;
231         struct drm_mm_node *child;
232         unsigned tmp = 0;
233
234         if (alignment)
235                 tmp = parent->start % alignment;
236
237         if (tmp) {
238                 align_splitoff =
239                     drm_mm_split_at_start(parent, alignment - tmp, 1);
240                 if (unlikely(align_splitoff == NULL))
241                         return NULL;
242         }
243
244         if (parent->size == size) {
245                 list_del_init(&parent->fl_entry);
246                 parent->free = 0;
247                 return parent;
248         } else {
249                 child = drm_mm_split_at_start(parent, size, 1);
250         }
251
252         if (align_splitoff)
253                 drm_mm_put_block(align_splitoff);
254
255         return child;
256 }
257 EXPORT_SYMBOL(drm_mm_get_block_atomic);
258
259 /*
260  * Put a block. Merge with the previous and / or next block if they are free.
261  * Otherwise add to the free stack.
262  */
263
264 void drm_mm_put_block(struct drm_mm_node *cur)
265 {
266
267         struct drm_mm *mm = cur->mm;
268         struct list_head *cur_head = &cur->ml_entry;
269         struct list_head *root_head = &mm->ml_entry;
270         struct drm_mm_node *prev_node = NULL;
271         struct drm_mm_node *next_node;
272
273         int merged = 0;
274
275         if (cur_head->prev != root_head) {
276                 prev_node =
277                     list_entry(cur_head->prev, struct drm_mm_node, ml_entry);
278                 if (prev_node->free) {
279                         prev_node->size += cur->size;
280                         merged = 1;
281                 }
282         }
283         if (cur_head->next != root_head) {
284                 next_node =
285                     list_entry(cur_head->next, struct drm_mm_node, ml_entry);
286                 if (next_node->free) {
287                         if (merged) {
288                                 prev_node->size += next_node->size;
289                                 list_del(&next_node->ml_entry);
290                                 list_del(&next_node->fl_entry);
291                                 if (mm->num_unused < MM_UNUSED_TARGET) {
292                                         list_add(&next_node->fl_entry,
293                                                  &mm->unused_nodes);
294                                         ++mm->num_unused;
295                                 } else
296                                         kfree(next_node);
297                         } else {
298                                 next_node->size += cur->size;
299                                 next_node->start = cur->start;
300                                 merged = 1;
301                         }
302                 }
303         }
304         if (!merged) {
305                 cur->free = 1;
306                 list_add(&cur->fl_entry, &mm->fl_entry);
307         } else {
308                 list_del(&cur->ml_entry);
309                 if (mm->num_unused < MM_UNUSED_TARGET) {
310                         list_add(&cur->fl_entry, &mm->unused_nodes);
311                         ++mm->num_unused;
312                 } else
313                         kfree(cur);
314         }
315 }
316
317 EXPORT_SYMBOL(drm_mm_put_block);
318
319 struct drm_mm_node *drm_mm_search_free(const struct drm_mm *mm,
320                                        unsigned long size,
321                                        unsigned alignment, int best_match)
322 {
323         struct list_head *list;
324         const struct list_head *free_stack = &mm->fl_entry;
325         struct drm_mm_node *entry;
326         struct drm_mm_node *best;
327         unsigned long best_size;
328         unsigned wasted;
329
330         best = NULL;
331         best_size = ~0UL;
332
333         list_for_each(list, free_stack) {
334                 entry = list_entry(list, struct drm_mm_node, fl_entry);
335                 wasted = 0;
336
337                 if (entry->size < size)
338                         continue;
339
340                 if (alignment) {
341                         register unsigned tmp = entry->start % alignment;
342                         if (tmp)
343                                 wasted += alignment - tmp;
344                 }
345
346                 if (entry->size >= size + wasted) {
347                         if (!best_match)
348                                 return entry;
349                         if (size < best_size) {
350                                 best = entry;
351                                 best_size = entry->size;
352                         }
353                 }
354         }
355
356         return best;
357 }
358 EXPORT_SYMBOL(drm_mm_search_free);
359
360 int drm_mm_clean(struct drm_mm * mm)
361 {
362         struct list_head *head = &mm->ml_entry;
363
364         return (head->next->next == head);
365 }
366 EXPORT_SYMBOL(drm_mm_clean);
367
368 int drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size)
369 {
370         INIT_LIST_HEAD(&mm->ml_entry);
371         INIT_LIST_HEAD(&mm->fl_entry);
372         INIT_LIST_HEAD(&mm->unused_nodes);
373         mm->num_unused = 0;
374         spin_lock_init(&mm->unused_lock);
375
376         return drm_mm_create_tail_node(mm, start, size, 0);
377 }
378 EXPORT_SYMBOL(drm_mm_init);
379
380 void drm_mm_takedown(struct drm_mm * mm)
381 {
382         struct list_head *bnode = mm->fl_entry.next;
383         struct drm_mm_node *entry;
384         struct drm_mm_node *next;
385
386         entry = list_entry(bnode, struct drm_mm_node, fl_entry);
387
388         if (entry->ml_entry.next != &mm->ml_entry ||
389             entry->fl_entry.next != &mm->fl_entry) {
390                 DRM_ERROR("Memory manager not clean. Delaying takedown\n");
391                 return;
392         }
393
394         list_del(&entry->fl_entry);
395         list_del(&entry->ml_entry);
396         kfree(entry);
397
398         spin_lock(&mm->unused_lock);
399         list_for_each_entry_safe(entry, next, &mm->unused_nodes, fl_entry) {
400                 list_del(&entry->fl_entry);
401                 kfree(entry);
402                 --mm->num_unused;
403         }
404         spin_unlock(&mm->unused_lock);
405
406         BUG_ON(mm->num_unused != 0);
407 }
408 EXPORT_SYMBOL(drm_mm_takedown);