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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 <drm/drmP.h>
45 #include <drm/drm_mm.h>
46 #include <linux/slab.h>
47 #include <linux/seq_file.h>
48 #include <linux/export.h>
49
50 #define MM_UNUSED_TARGET 4
51
52 static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
53                                                 unsigned long size,
54                                                 unsigned alignment,
55                                                 unsigned long color,
56                                                 enum drm_mm_search_flags flags);
57 static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm,
58                                                 unsigned long size,
59                                                 unsigned alignment,
60                                                 unsigned long color,
61                                                 unsigned long start,
62                                                 unsigned long end,
63                                                 enum drm_mm_search_flags flags);
64
65 static void drm_mm_insert_helper(struct drm_mm_node *hole_node,
66                                  struct drm_mm_node *node,
67                                  unsigned long size, unsigned alignment,
68                                  unsigned long color)
69 {
70         struct drm_mm *mm = hole_node->mm;
71         unsigned long hole_start = drm_mm_hole_node_start(hole_node);
72         unsigned long hole_end = drm_mm_hole_node_end(hole_node);
73         unsigned long adj_start = hole_start;
74         unsigned long adj_end = hole_end;
75
76         BUG_ON(node->allocated);
77
78         if (mm->color_adjust)
79                 mm->color_adjust(hole_node, color, &adj_start, &adj_end);
80
81         if (alignment) {
82                 unsigned tmp = adj_start % alignment;
83                 if (tmp)
84                         adj_start += alignment - tmp;
85         }
86
87         if (adj_start == hole_start) {
88                 hole_node->hole_follows = 0;
89                 list_del(&hole_node->hole_stack);
90         }
91
92         node->start = adj_start;
93         node->size = size;
94         node->mm = mm;
95         node->color = color;
96         node->allocated = 1;
97
98         INIT_LIST_HEAD(&node->hole_stack);
99         list_add(&node->node_list, &hole_node->node_list);
100
101         BUG_ON(node->start + node->size > adj_end);
102
103         node->hole_follows = 0;
104         if (__drm_mm_hole_node_start(node) < hole_end) {
105                 list_add(&node->hole_stack, &mm->hole_stack);
106                 node->hole_follows = 1;
107         }
108 }
109
110 int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node)
111 {
112         struct drm_mm_node *hole;
113         unsigned long end = node->start + node->size;
114         unsigned long hole_start;
115         unsigned long hole_end;
116
117         BUG_ON(node == NULL);
118
119         /* Find the relevant hole to add our node to */
120         drm_mm_for_each_hole(hole, mm, hole_start, hole_end) {
121                 if (hole_start > node->start || hole_end < end)
122                         continue;
123
124                 node->mm = mm;
125                 node->allocated = 1;
126
127                 INIT_LIST_HEAD(&node->hole_stack);
128                 list_add(&node->node_list, &hole->node_list);
129
130                 if (node->start == hole_start) {
131                         hole->hole_follows = 0;
132                         list_del_init(&hole->hole_stack);
133                 }
134
135                 node->hole_follows = 0;
136                 if (end != hole_end) {
137                         list_add(&node->hole_stack, &mm->hole_stack);
138                         node->hole_follows = 1;
139                 }
140
141                 return 0;
142         }
143
144         WARN(1, "no hole found for node 0x%lx + 0x%lx\n",
145              node->start, node->size);
146         return -ENOSPC;
147 }
148 EXPORT_SYMBOL(drm_mm_reserve_node);
149
150 /**
151  * Search for free space and insert a preallocated memory node. Returns
152  * -ENOSPC if no suitable free area is available. The preallocated memory node
153  * must be cleared.
154  */
155 int drm_mm_insert_node_generic(struct drm_mm *mm, struct drm_mm_node *node,
156                                unsigned long size, unsigned alignment,
157                                unsigned long color,
158                                enum drm_mm_search_flags flags)
159 {
160         struct drm_mm_node *hole_node;
161
162         hole_node = drm_mm_search_free_generic(mm, size, alignment,
163                                                color, flags);
164         if (!hole_node)
165                 return -ENOSPC;
166
167         drm_mm_insert_helper(hole_node, node, size, alignment, color);
168         return 0;
169 }
170 EXPORT_SYMBOL(drm_mm_insert_node_generic);
171
172 static void drm_mm_insert_helper_range(struct drm_mm_node *hole_node,
173                                        struct drm_mm_node *node,
174                                        unsigned long size, unsigned alignment,
175                                        unsigned long color,
176                                        unsigned long start, unsigned long end)
177 {
178         struct drm_mm *mm = hole_node->mm;
179         unsigned long hole_start = drm_mm_hole_node_start(hole_node);
180         unsigned long hole_end = drm_mm_hole_node_end(hole_node);
181         unsigned long adj_start = hole_start;
182         unsigned long adj_end = hole_end;
183
184         BUG_ON(!hole_node->hole_follows || node->allocated);
185
186         if (adj_start < start)
187                 adj_start = start;
188         if (adj_end > end)
189                 adj_end = end;
190
191         if (mm->color_adjust)
192                 mm->color_adjust(hole_node, color, &adj_start, &adj_end);
193
194         if (alignment) {
195                 unsigned tmp = adj_start % alignment;
196                 if (tmp)
197                         adj_start += alignment - tmp;
198         }
199
200         if (adj_start == hole_start) {
201                 hole_node->hole_follows = 0;
202                 list_del(&hole_node->hole_stack);
203         }
204
205         node->start = adj_start;
206         node->size = size;
207         node->mm = mm;
208         node->color = color;
209         node->allocated = 1;
210
211         INIT_LIST_HEAD(&node->hole_stack);
212         list_add(&node->node_list, &hole_node->node_list);
213
214         BUG_ON(node->start + node->size > adj_end);
215         BUG_ON(node->start + node->size > end);
216
217         node->hole_follows = 0;
218         if (__drm_mm_hole_node_start(node) < hole_end) {
219                 list_add(&node->hole_stack, &mm->hole_stack);
220                 node->hole_follows = 1;
221         }
222 }
223
224 /**
225  * Search for free space and insert a preallocated memory node. Returns
226  * -ENOSPC if no suitable free area is available. This is for range
227  * restricted allocations. The preallocated memory node must be cleared.
228  */
229 int drm_mm_insert_node_in_range_generic(struct drm_mm *mm, struct drm_mm_node *node,
230                                         unsigned long size, unsigned alignment, unsigned long color,
231                                         unsigned long start, unsigned long end,
232                                         enum drm_mm_search_flags flags)
233 {
234         struct drm_mm_node *hole_node;
235
236         hole_node = drm_mm_search_free_in_range_generic(mm,
237                                                         size, alignment, color,
238                                                         start, end, flags);
239         if (!hole_node)
240                 return -ENOSPC;
241
242         drm_mm_insert_helper_range(hole_node, node,
243                                    size, alignment, color,
244                                    start, end);
245         return 0;
246 }
247 EXPORT_SYMBOL(drm_mm_insert_node_in_range_generic);
248
249 /**
250  * Remove a memory node from the allocator.
251  */
252 void drm_mm_remove_node(struct drm_mm_node *node)
253 {
254         struct drm_mm *mm = node->mm;
255         struct drm_mm_node *prev_node;
256
257         BUG_ON(node->scanned_block || node->scanned_prev_free
258                                    || node->scanned_next_free);
259
260         prev_node =
261             list_entry(node->node_list.prev, struct drm_mm_node, node_list);
262
263         if (node->hole_follows) {
264                 BUG_ON(__drm_mm_hole_node_start(node) ==
265                        __drm_mm_hole_node_end(node));
266                 list_del(&node->hole_stack);
267         } else
268                 BUG_ON(__drm_mm_hole_node_start(node) !=
269                        __drm_mm_hole_node_end(node));
270
271
272         if (!prev_node->hole_follows) {
273                 prev_node->hole_follows = 1;
274                 list_add(&prev_node->hole_stack, &mm->hole_stack);
275         } else
276                 list_move(&prev_node->hole_stack, &mm->hole_stack);
277
278         list_del(&node->node_list);
279         node->allocated = 0;
280 }
281 EXPORT_SYMBOL(drm_mm_remove_node);
282
283 static int check_free_hole(unsigned long start, unsigned long end,
284                            unsigned long size, unsigned alignment)
285 {
286         if (end - start < size)
287                 return 0;
288
289         if (alignment) {
290                 unsigned tmp = start % alignment;
291                 if (tmp)
292                         start += alignment - tmp;
293         }
294
295         return end >= start + size;
296 }
297
298 static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
299                                                       unsigned long size,
300                                                       unsigned alignment,
301                                                       unsigned long color,
302                                                       enum drm_mm_search_flags flags)
303 {
304         struct drm_mm_node *entry;
305         struct drm_mm_node *best;
306         unsigned long adj_start;
307         unsigned long adj_end;
308         unsigned long best_size;
309
310         BUG_ON(mm->scanned_blocks);
311
312         best = NULL;
313         best_size = ~0UL;
314
315         drm_mm_for_each_hole(entry, mm, adj_start, adj_end) {
316                 if (mm->color_adjust) {
317                         mm->color_adjust(entry, color, &adj_start, &adj_end);
318                         if (adj_end <= adj_start)
319                                 continue;
320                 }
321
322                 if (!check_free_hole(adj_start, adj_end, size, alignment))
323                         continue;
324
325                 if (!(flags & DRM_MM_SEARCH_BEST))
326                         return entry;
327
328                 if (entry->size < best_size) {
329                         best = entry;
330                         best_size = entry->size;
331                 }
332         }
333
334         return best;
335 }
336
337 static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm,
338                                                         unsigned long size,
339                                                         unsigned alignment,
340                                                         unsigned long color,
341                                                         unsigned long start,
342                                                         unsigned long end,
343                                                         enum drm_mm_search_flags flags)
344 {
345         struct drm_mm_node *entry;
346         struct drm_mm_node *best;
347         unsigned long adj_start;
348         unsigned long adj_end;
349         unsigned long best_size;
350
351         BUG_ON(mm->scanned_blocks);
352
353         best = NULL;
354         best_size = ~0UL;
355
356         drm_mm_for_each_hole(entry, mm, adj_start, adj_end) {
357                 if (adj_start < start)
358                         adj_start = start;
359                 if (adj_end > end)
360                         adj_end = end;
361
362                 if (mm->color_adjust) {
363                         mm->color_adjust(entry, color, &adj_start, &adj_end);
364                         if (adj_end <= adj_start)
365                                 continue;
366                 }
367
368                 if (!check_free_hole(adj_start, adj_end, size, alignment))
369                         continue;
370
371                 if (!(flags & DRM_MM_SEARCH_BEST))
372                         return entry;
373
374                 if (entry->size < best_size) {
375                         best = entry;
376                         best_size = entry->size;
377                 }
378         }
379
380         return best;
381 }
382
383 /**
384  * Moves an allocation. To be used with embedded struct drm_mm_node.
385  */
386 void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new)
387 {
388         list_replace(&old->node_list, &new->node_list);
389         list_replace(&old->hole_stack, &new->hole_stack);
390         new->hole_follows = old->hole_follows;
391         new->mm = old->mm;
392         new->start = old->start;
393         new->size = old->size;
394         new->color = old->color;
395
396         old->allocated = 0;
397         new->allocated = 1;
398 }
399 EXPORT_SYMBOL(drm_mm_replace_node);
400
401 /**
402  * Initializa lru scanning.
403  *
404  * This simply sets up the scanning routines with the parameters for the desired
405  * hole.
406  *
407  * Warning: As long as the scan list is non-empty, no other operations than
408  * adding/removing nodes to/from the scan list are allowed.
409  */
410 void drm_mm_init_scan(struct drm_mm *mm,
411                       unsigned long size,
412                       unsigned alignment,
413                       unsigned long color)
414 {
415         mm->scan_color = color;
416         mm->scan_alignment = alignment;
417         mm->scan_size = size;
418         mm->scanned_blocks = 0;
419         mm->scan_hit_start = 0;
420         mm->scan_hit_end = 0;
421         mm->scan_check_range = 0;
422         mm->prev_scanned_node = NULL;
423 }
424 EXPORT_SYMBOL(drm_mm_init_scan);
425
426 /**
427  * Initializa lru scanning.
428  *
429  * This simply sets up the scanning routines with the parameters for the desired
430  * hole. This version is for range-restricted scans.
431  *
432  * Warning: As long as the scan list is non-empty, no other operations than
433  * adding/removing nodes to/from the scan list are allowed.
434  */
435 void drm_mm_init_scan_with_range(struct drm_mm *mm,
436                                  unsigned long size,
437                                  unsigned alignment,
438                                  unsigned long color,
439                                  unsigned long start,
440                                  unsigned long end)
441 {
442         mm->scan_color = color;
443         mm->scan_alignment = alignment;
444         mm->scan_size = size;
445         mm->scanned_blocks = 0;
446         mm->scan_hit_start = 0;
447         mm->scan_hit_end = 0;
448         mm->scan_start = start;
449         mm->scan_end = end;
450         mm->scan_check_range = 1;
451         mm->prev_scanned_node = NULL;
452 }
453 EXPORT_SYMBOL(drm_mm_init_scan_with_range);
454
455 /**
456  * Add a node to the scan list that might be freed to make space for the desired
457  * hole.
458  *
459  * Returns non-zero, if a hole has been found, zero otherwise.
460  */
461 int drm_mm_scan_add_block(struct drm_mm_node *node)
462 {
463         struct drm_mm *mm = node->mm;
464         struct drm_mm_node *prev_node;
465         unsigned long hole_start, hole_end;
466         unsigned long adj_start, adj_end;
467
468         mm->scanned_blocks++;
469
470         BUG_ON(node->scanned_block);
471         node->scanned_block = 1;
472
473         prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
474                                node_list);
475
476         node->scanned_preceeds_hole = prev_node->hole_follows;
477         prev_node->hole_follows = 1;
478         list_del(&node->node_list);
479         node->node_list.prev = &prev_node->node_list;
480         node->node_list.next = &mm->prev_scanned_node->node_list;
481         mm->prev_scanned_node = node;
482
483         adj_start = hole_start = drm_mm_hole_node_start(prev_node);
484         adj_end = hole_end = drm_mm_hole_node_end(prev_node);
485
486         if (mm->scan_check_range) {
487                 if (adj_start < mm->scan_start)
488                         adj_start = mm->scan_start;
489                 if (adj_end > mm->scan_end)
490                         adj_end = mm->scan_end;
491         }
492
493         if (mm->color_adjust)
494                 mm->color_adjust(prev_node, mm->scan_color,
495                                  &adj_start, &adj_end);
496
497         if (check_free_hole(adj_start, adj_end,
498                             mm->scan_size, mm->scan_alignment)) {
499                 mm->scan_hit_start = hole_start;
500                 mm->scan_hit_end = hole_end;
501                 return 1;
502         }
503
504         return 0;
505 }
506 EXPORT_SYMBOL(drm_mm_scan_add_block);
507
508 /**
509  * Remove a node from the scan list.
510  *
511  * Nodes _must_ be removed in the exact same order from the scan list as they
512  * have been added, otherwise the internal state of the memory manager will be
513  * corrupted.
514  *
515  * When the scan list is empty, the selected memory nodes can be freed. An
516  * immediately following drm_mm_search_free with !DRM_MM_SEARCH_BEST will then
517  * return the just freed block (because its at the top of the free_stack list).
518  *
519  * Returns one if this block should be evicted, zero otherwise. Will always
520  * return zero when no hole has been found.
521  */
522 int drm_mm_scan_remove_block(struct drm_mm_node *node)
523 {
524         struct drm_mm *mm = node->mm;
525         struct drm_mm_node *prev_node;
526
527         mm->scanned_blocks--;
528
529         BUG_ON(!node->scanned_block);
530         node->scanned_block = 0;
531
532         prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
533                                node_list);
534
535         prev_node->hole_follows = node->scanned_preceeds_hole;
536         list_add(&node->node_list, &prev_node->node_list);
537
538          return (drm_mm_hole_node_end(node) > mm->scan_hit_start &&
539                  node->start < mm->scan_hit_end);
540 }
541 EXPORT_SYMBOL(drm_mm_scan_remove_block);
542
543 int drm_mm_clean(struct drm_mm * mm)
544 {
545         struct list_head *head = &mm->head_node.node_list;
546
547         return (head->next->next == head);
548 }
549 EXPORT_SYMBOL(drm_mm_clean);
550
551 void drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size)
552 {
553         INIT_LIST_HEAD(&mm->hole_stack);
554         mm->scanned_blocks = 0;
555
556         /* Clever trick to avoid a special case in the free hole tracking. */
557         INIT_LIST_HEAD(&mm->head_node.node_list);
558         INIT_LIST_HEAD(&mm->head_node.hole_stack);
559         mm->head_node.hole_follows = 1;
560         mm->head_node.scanned_block = 0;
561         mm->head_node.scanned_prev_free = 0;
562         mm->head_node.scanned_next_free = 0;
563         mm->head_node.mm = mm;
564         mm->head_node.start = start + size;
565         mm->head_node.size = start - mm->head_node.start;
566         list_add_tail(&mm->head_node.hole_stack, &mm->hole_stack);
567
568         mm->color_adjust = NULL;
569 }
570 EXPORT_SYMBOL(drm_mm_init);
571
572 void drm_mm_takedown(struct drm_mm * mm)
573 {
574         WARN(!list_empty(&mm->head_node.node_list),
575              "Memory manager not clean during takedown.\n");
576 }
577 EXPORT_SYMBOL(drm_mm_takedown);
578
579 static unsigned long drm_mm_debug_hole(struct drm_mm_node *entry,
580                                        const char *prefix)
581 {
582         unsigned long hole_start, hole_end, hole_size;
583
584         if (entry->hole_follows) {
585                 hole_start = drm_mm_hole_node_start(entry);
586                 hole_end = drm_mm_hole_node_end(entry);
587                 hole_size = hole_end - hole_start;
588                 printk(KERN_DEBUG "%s 0x%08lx-0x%08lx: %8lu: free\n",
589                         prefix, hole_start, hole_end,
590                         hole_size);
591                 return hole_size;
592         }
593
594         return 0;
595 }
596
597 void drm_mm_debug_table(struct drm_mm *mm, const char *prefix)
598 {
599         struct drm_mm_node *entry;
600         unsigned long total_used = 0, total_free = 0, total = 0;
601
602         total_free += drm_mm_debug_hole(&mm->head_node, prefix);
603
604         drm_mm_for_each_node(entry, mm) {
605                 printk(KERN_DEBUG "%s 0x%08lx-0x%08lx: %8lu: used\n",
606                         prefix, entry->start, entry->start + entry->size,
607                         entry->size);
608                 total_used += entry->size;
609                 total_free += drm_mm_debug_hole(entry, prefix);
610         }
611         total = total_free + total_used;
612
613         printk(KERN_DEBUG "%s total: %lu, used %lu free %lu\n", prefix, total,
614                 total_used, total_free);
615 }
616 EXPORT_SYMBOL(drm_mm_debug_table);
617
618 #if defined(CONFIG_DEBUG_FS)
619 static unsigned long drm_mm_dump_hole(struct seq_file *m, struct drm_mm_node *entry)
620 {
621         unsigned long hole_start, hole_end, hole_size;
622
623         if (entry->hole_follows) {
624                 hole_start = drm_mm_hole_node_start(entry);
625                 hole_end = drm_mm_hole_node_end(entry);
626                 hole_size = hole_end - hole_start;
627                 seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: free\n",
628                                 hole_start, hole_end, hole_size);
629                 return hole_size;
630         }
631
632         return 0;
633 }
634
635 int drm_mm_dump_table(struct seq_file *m, struct drm_mm *mm)
636 {
637         struct drm_mm_node *entry;
638         unsigned long total_used = 0, total_free = 0, total = 0;
639
640         total_free += drm_mm_dump_hole(m, &mm->head_node);
641
642         drm_mm_for_each_node(entry, mm) {
643                 seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: used\n",
644                                 entry->start, entry->start + entry->size,
645                                 entry->size);
646                 total_used += entry->size;
647                 total_free += drm_mm_dump_hole(m, entry);
648         }
649         total = total_free + total_used;
650
651         seq_printf(m, "total: %lu, used %lu free %lu\n", total, total_used, total_free);
652         return 0;
653 }
654 EXPORT_SYMBOL(drm_mm_dump_table);
655 #endif