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/**
 51 * DOC: Overview
 52 *
 53 * drm_mm provides a simple range allocator. The drivers are free to use the
 54 * resource allocator from the linux core if it suits them, the upside of drm_mm
 55 * is that it's in the DRM core. Which means that it's easier to extend for
 56 * some of the crazier special purpose needs of gpus.
 57 *
 58 * The main data struct is &drm_mm, allocations are tracked in &drm_mm_node.
 59 * Drivers are free to embed either of them into their own suitable
 60 * datastructures. drm_mm itself will not do any allocations of its own, so if
 61 * drivers choose not to embed nodes they need to still allocate them
 62 * themselves.
 63 *
 64 * The range allocator also supports reservation of preallocated blocks. This is
 65 * useful for taking over initial mode setting configurations from the firmware,
 66 * where an object needs to be created which exactly matches the firmware's
 67 * scanout target. As long as the range is still free it can be inserted anytime
 68 * after the allocator is initialized, which helps with avoiding looped
 69 * depencies in the driver load sequence.
 70 *
 71 * drm_mm maintains a stack of most recently freed holes, which of all
 72 * simplistic datastructures seems to be a fairly decent approach to clustering
 73 * allocations and avoiding too much fragmentation. This means free space
 74 * searches are O(num_holes). Given that all the fancy features drm_mm supports
 75 * something better would be fairly complex and since gfx thrashing is a fairly
 76 * steep cliff not a real concern. Removing a node again is O(1).
 77 *
 78 * drm_mm supports a few features: Alignment and range restrictions can be
 79 * supplied. Further more every &drm_mm_node has a color value (which is just an
 80 * opaqua unsigned long) which in conjunction with a driver callback can be used
 81 * to implement sophisticated placement restrictions. The i915 DRM driver uses
 82 * this to implement guard pages between incompatible caching domains in the
 83 * graphics TT.
 84 *
 85 * Two behaviors are supported for searching and allocating: bottom-up and top-down.
 86 * The default is bottom-up. Top-down allocation can be used if the memory area
 87 * has different restrictions, or just to reduce fragmentation.
 88 *
 89 * Finally iteration helpers to walk all nodes and all holes are provided as are
 90 * some basic allocator dumpers for debugging.
 91 */
 
 
 
 92
 93static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
 94						u64 size,
 95						unsigned alignment,
 96						unsigned long color,
 97						enum drm_mm_search_flags flags);
 98static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm,
 99						u64 size,
100						unsigned alignment,
101						unsigned long color,
102						u64 start,
103						u64 end,
104						enum drm_mm_search_flags flags);
105
106static void drm_mm_insert_helper(struct drm_mm_node *hole_node,
107				 struct drm_mm_node *node,
108				 u64 size, unsigned alignment,
109				 unsigned long color,
110				 enum drm_mm_allocator_flags flags)
111{
112	struct drm_mm *mm = hole_node->mm;
113	u64 hole_start = drm_mm_hole_node_start(hole_node);
114	u64 hole_end = drm_mm_hole_node_end(hole_node);
115	u64 adj_start = hole_start;
116	u64 adj_end = hole_end;
 
117
118	BUG_ON(node->allocated);
 
 
 
119
120	if (mm->color_adjust)
121		mm->color_adjust(hole_node, color, &adj_start, &adj_end);
 
 
 
122
123	if (flags & DRM_MM_CREATE_TOP)
124		adj_start = adj_end - size;
125
126	if (alignment) {
127		u64 tmp = adj_start;
128		unsigned rem;
 
 
 
 
 
129
130		rem = do_div(tmp, alignment);
131		if (rem) {
132			if (flags & DRM_MM_CREATE_TOP)
133				adj_start -= rem;
134			else
135				adj_start += alignment - rem;
136		}
137	}
138
139	BUG_ON(adj_start < hole_start);
140	BUG_ON(adj_end > hole_end);
141
142	if (adj_start == hole_start) {
143		hole_node->hole_follows = 0;
144		list_del(&hole_node->hole_stack);
145	}
 
146
147	node->start = adj_start;
148	node->size = size;
149	node->mm = mm;
150	node->color = color;
151	node->allocated = 1;
152
153	INIT_LIST_HEAD(&node->hole_stack);
154	list_add(&node->node_list, &hole_node->node_list);
155
156	BUG_ON(node->start + node->size > adj_end);
157
158	node->hole_follows = 0;
159	if (__drm_mm_hole_node_start(node) < hole_end) {
160		list_add(&node->hole_stack, &mm->hole_stack);
161		node->hole_follows = 1;
 
 
162	}
163}
164
165/**
166 * drm_mm_reserve_node - insert an pre-initialized node
167 * @mm: drm_mm allocator to insert @node into
168 * @node: drm_mm_node to insert
169 *
170 * This functions inserts an already set-up drm_mm_node into the allocator,
171 * meaning that start, size and color must be set by the caller. This is useful
172 * to initialize the allocator with preallocated objects which must be set-up
173 * before the range allocator can be set-up, e.g. when taking over a firmware
174 * framebuffer.
175 *
176 * Returns:
177 * 0 on success, -ENOSPC if there's no hole where @node is.
178 */
179int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node)
180{
181	struct drm_mm_node *hole;
182	u64 end = node->start + node->size;
183	u64 hole_start;
184	u64 hole_end;
185
186	BUG_ON(node == NULL);
187
188	/* Find the relevant hole to add our node to */
189	drm_mm_for_each_hole(hole, mm, hole_start, hole_end) {
190		if (hole_start > node->start || hole_end < end)
191			continue;
192
193		node->mm = mm;
194		node->allocated = 1;
 
195
196		INIT_LIST_HEAD(&node->hole_stack);
197		list_add(&node->node_list, &hole->node_list);
198
199		if (node->start == hole_start) {
200			hole->hole_follows = 0;
201			list_del_init(&hole->hole_stack);
202		}
203
204		node->hole_follows = 0;
205		if (end != hole_end) {
206			list_add(&node->hole_stack, &mm->hole_stack);
207			node->hole_follows = 1;
208		}
209
210		return 0;
211	}
212
213	return -ENOSPC;
214}
215EXPORT_SYMBOL(drm_mm_reserve_node);
216
217/**
218 * drm_mm_insert_node_generic - search for space and insert @node
219 * @mm: drm_mm to allocate from
220 * @node: preallocate node to insert
221 * @size: size of the allocation
222 * @alignment: alignment of the allocation
223 * @color: opaque tag value to use for this node
224 * @sflags: flags to fine-tune the allocation search
225 * @aflags: flags to fine-tune the allocation behavior
226 *
227 * The preallocated node must be cleared to 0.
228 *
229 * Returns:
230 * 0 on success, -ENOSPC if there's no suitable hole.
231 */
232int drm_mm_insert_node_generic(struct drm_mm *mm, struct drm_mm_node *node,
233			       u64 size, unsigned alignment,
234			       unsigned long color,
235			       enum drm_mm_search_flags sflags,
236			       enum drm_mm_allocator_flags aflags)
237{
238	struct drm_mm_node *hole_node;
239
240	hole_node = drm_mm_search_free_generic(mm, size, alignment,
241					       color, sflags);
242	if (!hole_node)
243		return -ENOSPC;
244
245	drm_mm_insert_helper(hole_node, node, size, alignment, color, aflags);
 
246	return 0;
247}
248EXPORT_SYMBOL(drm_mm_insert_node_generic);
249
250static void drm_mm_insert_helper_range(struct drm_mm_node *hole_node,
251				       struct drm_mm_node *node,
252				       u64 size, unsigned alignment,
253				       unsigned long color,
254				       u64 start, u64 end,
255				       enum drm_mm_allocator_flags flags)
256{
257	struct drm_mm *mm = hole_node->mm;
258	u64 hole_start = drm_mm_hole_node_start(hole_node);
259	u64 hole_end = drm_mm_hole_node_end(hole_node);
260	u64 adj_start = hole_start;
261	u64 adj_end = hole_end;
262
263	BUG_ON(!hole_node->hole_follows || node->allocated);
264
265	if (adj_start < start)
266		adj_start = start;
267	if (adj_end > end)
268		adj_end = end;
269
270	if (mm->color_adjust)
271		mm->color_adjust(hole_node, color, &adj_start, &adj_end);
272
273	if (flags & DRM_MM_CREATE_TOP)
274		adj_start = adj_end - size;
275
276	if (alignment) {
277		u64 tmp = adj_start;
278		unsigned rem;
279
280		rem = do_div(tmp, alignment);
281		if (rem) {
282			if (flags & DRM_MM_CREATE_TOP)
283				adj_start -= rem;
284			else
285				adj_start += alignment - rem;
286		}
287	}
288
289	if (adj_start == hole_start) {
290		hole_node->hole_follows = 0;
291		list_del(&hole_node->hole_stack);
292	}
293
294	node->start = adj_start;
295	node->size = size;
296	node->mm = mm;
297	node->color = color;
298	node->allocated = 1;
299
300	INIT_LIST_HEAD(&node->hole_stack);
301	list_add(&node->node_list, &hole_node->node_list);
302
303	BUG_ON(node->start < start);
304	BUG_ON(node->start < adj_start);
305	BUG_ON(node->start + node->size > adj_end);
306	BUG_ON(node->start + node->size > end);
307
308	node->hole_follows = 0;
309	if (__drm_mm_hole_node_start(node) < hole_end) {
310		list_add(&node->hole_stack, &mm->hole_stack);
311		node->hole_follows = 1;
 
 
312	}
313}
314
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
315/**
316 * drm_mm_insert_node_in_range_generic - ranged search for space and insert @node
317 * @mm: drm_mm to allocate from
318 * @node: preallocate node to insert
319 * @size: size of the allocation
320 * @alignment: alignment of the allocation
321 * @color: opaque tag value to use for this node
322 * @start: start of the allowed range for this node
323 * @end: end of the allowed range for this node
324 * @sflags: flags to fine-tune the allocation search
325 * @aflags: flags to fine-tune the allocation behavior
326 *
327 * The preallocated node must be cleared to 0.
328 *
329 * Returns:
330 * 0 on success, -ENOSPC if there's no suitable hole.
331 */
332int drm_mm_insert_node_in_range_generic(struct drm_mm *mm, struct drm_mm_node *node,
333					u64 size, unsigned alignment,
334					unsigned long color,
335					u64 start, u64 end,
336					enum drm_mm_search_flags sflags,
337					enum drm_mm_allocator_flags aflags)
338{
339	struct drm_mm_node *hole_node;
340
341	hole_node = drm_mm_search_free_in_range_generic(mm,
342							size, alignment, color,
343							start, end, sflags);
344	if (!hole_node)
345		return -ENOSPC;
346
347	drm_mm_insert_helper_range(hole_node, node,
348				   size, alignment, color,
349				   start, end, aflags);
350	return 0;
351}
352EXPORT_SYMBOL(drm_mm_insert_node_in_range_generic);
353
354/**
355 * drm_mm_remove_node - Remove a memory node from the allocator.
356 * @node: drm_mm_node to remove
357 *
358 * This just removes a node from its drm_mm allocator. The node does not need to
359 * be cleared again before it can be re-inserted into this or any other drm_mm
360 * allocator. It is a bug to call this function on a un-allocated node.
361 */
362void drm_mm_remove_node(struct drm_mm_node *node)
363{
364	struct drm_mm *mm = node->mm;
365	struct drm_mm_node *prev_node;
366
367	if (WARN_ON(!node->allocated))
368		return;
369
370	BUG_ON(node->scanned_block || node->scanned_prev_free
371				   || node->scanned_next_free);
372
373	prev_node =
374	    list_entry(node->node_list.prev, struct drm_mm_node, node_list);
375
376	if (node->hole_follows) {
377		BUG_ON(__drm_mm_hole_node_start(node) ==
378		       __drm_mm_hole_node_end(node));
379		list_del(&node->hole_stack);
380	} else
381		BUG_ON(__drm_mm_hole_node_start(node) !=
382		       __drm_mm_hole_node_end(node));
383
384
385	if (!prev_node->hole_follows) {
386		prev_node->hole_follows = 1;
387		list_add(&prev_node->hole_stack, &mm->hole_stack);
388	} else
389		list_move(&prev_node->hole_stack, &mm->hole_stack);
390
391	list_del(&node->node_list);
392	node->allocated = 0;
393}
394EXPORT_SYMBOL(drm_mm_remove_node);
395
396static int check_free_hole(u64 start, u64 end, u64 size, unsigned alignment)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
397{
 
 
398	if (end - start < size)
399		return 0;
400
401	if (alignment) {
402		u64 tmp = start;
403		unsigned rem;
 
 
404
405		rem = do_div(tmp, alignment);
406		if (rem)
407			start += alignment - rem;
408	}
409
410	return end >= start + size;
411}
412
413static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
414						      u64 size,
415						      unsigned alignment,
416						      unsigned long color,
417						      enum drm_mm_search_flags flags)
418{
419	struct drm_mm_node *entry;
420	struct drm_mm_node *best;
421	u64 adj_start;
422	u64 adj_end;
423	u64 best_size;
424
425	BUG_ON(mm->scanned_blocks);
426
427	best = NULL;
428	best_size = ~0UL;
429
430	__drm_mm_for_each_hole(entry, mm, adj_start, adj_end,
431			       flags & DRM_MM_SEARCH_BELOW) {
432		u64 hole_size = adj_end - adj_start;
433
434		if (mm->color_adjust) {
435			mm->color_adjust(entry, color, &adj_start, &adj_end);
436			if (adj_end <= adj_start)
437				continue;
438		}
439
440		if (!check_free_hole(adj_start, adj_end, size, alignment))
441			continue;
442
443		if (!(flags & DRM_MM_SEARCH_BEST))
444			return entry;
445
446		if (hole_size < best_size) {
447			best = entry;
448			best_size = hole_size;
449		}
450	}
451
452	return best;
453}
 
454
455static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm,
456							u64 size,
457							unsigned alignment,
458							unsigned long color,
459							u64 start,
460							u64 end,
461							enum drm_mm_search_flags flags)
462{
463	struct drm_mm_node *entry;
464	struct drm_mm_node *best;
465	u64 adj_start;
466	u64 adj_end;
467	u64 best_size;
468
469	BUG_ON(mm->scanned_blocks);
470
471	best = NULL;
472	best_size = ~0UL;
473
474	__drm_mm_for_each_hole(entry, mm, adj_start, adj_end,
475			       flags & DRM_MM_SEARCH_BELOW) {
476		u64 hole_size = adj_end - adj_start;
477
478		if (adj_start < start)
479			adj_start = start;
480		if (adj_end > end)
481			adj_end = end;
482
483		if (mm->color_adjust) {
484			mm->color_adjust(entry, color, &adj_start, &adj_end);
485			if (adj_end <= adj_start)
486				continue;
487		}
488
 
489		if (!check_free_hole(adj_start, adj_end, size, alignment))
490			continue;
491
492		if (!(flags & DRM_MM_SEARCH_BEST))
493			return entry;
494
495		if (hole_size < best_size) {
496			best = entry;
497			best_size = hole_size;
498		}
499	}
500
501	return best;
502}
 
503
504/**
505 * drm_mm_replace_node - move an allocation from @old to @new
506 * @old: drm_mm_node to remove from the allocator
507 * @new: drm_mm_node which should inherit @old's allocation
508 *
509 * This is useful for when drivers embed the drm_mm_node structure and hence
510 * can't move allocations by reassigning pointers. It's a combination of remove
511 * and insert with the guarantee that the allocation start will match.
512 */
513void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new)
514{
515	list_replace(&old->node_list, &new->node_list);
516	list_replace(&old->hole_stack, &new->hole_stack);
517	new->hole_follows = old->hole_follows;
518	new->mm = old->mm;
519	new->start = old->start;
520	new->size = old->size;
521	new->color = old->color;
522
523	old->allocated = 0;
524	new->allocated = 1;
525}
526EXPORT_SYMBOL(drm_mm_replace_node);
527
528/**
529 * DOC: lru scan roaster
530 *
531 * Very often GPUs need to have continuous allocations for a given object. When
532 * evicting objects to make space for a new one it is therefore not most
533 * efficient when we simply start to select all objects from the tail of an LRU
534 * until there's a suitable hole: Especially for big objects or nodes that
535 * otherwise have special allocation constraints there's a good chance we evict
536 * lots of (smaller) objects unecessarily.
537 *
538 * The DRM range allocator supports this use-case through the scanning
539 * interfaces. First a scan operation needs to be initialized with
540 * drm_mm_init_scan() or drm_mm_init_scan_with_range(). The the driver adds
541 * objects to the roaster (probably by walking an LRU list, but this can be
542 * freely implemented) until a suitable hole is found or there's no further
543 * evitable object.
544 *
545 * The the driver must walk through all objects again in exactly the reverse
546 * order to restore the allocator state. Note that while the allocator is used
547 * in the scan mode no other operation is allowed.
548 *
549 * Finally the driver evicts all objects selected in the scan. Adding and
550 * removing an object is O(1), and since freeing a node is also O(1) the overall
551 * complexity is O(scanned_objects). So like the free stack which needs to be
552 * walked before a scan operation even begins this is linear in the number of
553 * objects. It doesn't seem to hurt badly.
554 */
555
556/**
557 * drm_mm_init_scan - initialize lru scanning
558 * @mm: drm_mm to scan
559 * @size: size of the allocation
560 * @alignment: alignment of the allocation
561 * @color: opaque tag value to use for the allocation
562 *
563 * This simply sets up the scanning routines with the parameters for the desired
564 * hole. Note that there's no need to specify allocation flags, since they only
565 * change the place a node is allocated from within a suitable hole.
566 *
567 * Warning:
568 * As long as the scan list is non-empty, no other operations than
569 * adding/removing nodes to/from the scan list are allowed.
570 */
571void drm_mm_init_scan(struct drm_mm *mm,
572		      u64 size,
573		      unsigned alignment,
574		      unsigned long color)
575{
576	mm->scan_color = color;
577	mm->scan_alignment = alignment;
578	mm->scan_size = size;
579	mm->scanned_blocks = 0;
580	mm->scan_hit_start = 0;
581	mm->scan_hit_end = 0;
582	mm->scan_check_range = 0;
583	mm->prev_scanned_node = NULL;
584}
585EXPORT_SYMBOL(drm_mm_init_scan);
586
587/**
588 * drm_mm_init_scan - initialize range-restricted lru scanning
589 * @mm: drm_mm to scan
590 * @size: size of the allocation
591 * @alignment: alignment of the allocation
592 * @color: opaque tag value to use for the allocation
593 * @start: start of the allowed range for the allocation
594 * @end: end of the allowed range for the allocation
595 *
596 * This simply sets up the scanning routines with the parameters for the desired
597 * hole. Note that there's no need to specify allocation flags, since they only
598 * change the place a node is allocated from within a suitable hole.
599 *
600 * Warning:
601 * As long as the scan list is non-empty, no other operations than
602 * adding/removing nodes to/from the scan list are allowed.
603 */
604void drm_mm_init_scan_with_range(struct drm_mm *mm,
605				 u64 size,
606				 unsigned alignment,
607				 unsigned long color,
608				 u64 start,
609				 u64 end)
610{
611	mm->scan_color = color;
612	mm->scan_alignment = alignment;
613	mm->scan_size = size;
614	mm->scanned_blocks = 0;
615	mm->scan_hit_start = 0;
616	mm->scan_hit_end = 0;
617	mm->scan_start = start;
618	mm->scan_end = end;
619	mm->scan_check_range = 1;
620	mm->prev_scanned_node = NULL;
621}
622EXPORT_SYMBOL(drm_mm_init_scan_with_range);
623
624/**
625 * drm_mm_scan_add_block - add a node to the scan list
626 * @node: drm_mm_node to add
627 *
628 * Add a node to the scan list that might be freed to make space for the desired
629 * hole.
630 *
631 * Returns:
632 * True if a hole has been found, false otherwise.
633 */
634bool drm_mm_scan_add_block(struct drm_mm_node *node)
635{
636	struct drm_mm *mm = node->mm;
637	struct drm_mm_node *prev_node;
638	u64 hole_start, hole_end;
639	u64 adj_start, adj_end;
 
640
641	mm->scanned_blocks++;
642
643	BUG_ON(node->scanned_block);
644	node->scanned_block = 1;
645
646	prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
647			       node_list);
648
649	node->scanned_preceeds_hole = prev_node->hole_follows;
650	prev_node->hole_follows = 1;
651	list_del(&node->node_list);
652	node->node_list.prev = &prev_node->node_list;
653	node->node_list.next = &mm->prev_scanned_node->node_list;
654	mm->prev_scanned_node = node;
655
656	adj_start = hole_start = drm_mm_hole_node_start(prev_node);
657	adj_end = hole_end = drm_mm_hole_node_end(prev_node);
658
659	if (mm->scan_check_range) {
660		if (adj_start < mm->scan_start)
661			adj_start = mm->scan_start;
662		if (adj_end > mm->scan_end)
663			adj_end = mm->scan_end;
 
 
 
664	}
665
666	if (mm->color_adjust)
667		mm->color_adjust(prev_node, mm->scan_color,
668				 &adj_start, &adj_end);
669
670	if (check_free_hole(adj_start, adj_end,
671			    mm->scan_size, mm->scan_alignment)) {
672		mm->scan_hit_start = hole_start;
673		mm->scan_hit_end = hole_end;
674		return true;
 
675	}
676
677	return false;
678}
679EXPORT_SYMBOL(drm_mm_scan_add_block);
680
681/**
682 * drm_mm_scan_remove_block - remove a node from the scan list
683 * @node: drm_mm_node to remove
684 *
685 * Nodes _must_ be removed in the exact same order from the scan list as they
686 * have been added, otherwise the internal state of the memory manager will be
687 * corrupted.
688 *
689 * When the scan list is empty, the selected memory nodes can be freed. An
690 * immediately following drm_mm_search_free with !DRM_MM_SEARCH_BEST will then
691 * return the just freed block (because its at the top of the free_stack list).
692 *
693 * Returns:
694 * True if this block should be evicted, false otherwise. Will always
695 * return false when no hole has been found.
696 */
697bool drm_mm_scan_remove_block(struct drm_mm_node *node)
698{
699	struct drm_mm *mm = node->mm;
700	struct drm_mm_node *prev_node;
701
702	mm->scanned_blocks--;
703
704	BUG_ON(!node->scanned_block);
705	node->scanned_block = 0;
706
707	prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
708			       node_list);
709
710	prev_node->hole_follows = node->scanned_preceeds_hole;
 
711	list_add(&node->node_list, &prev_node->node_list);
712
713	 return (drm_mm_hole_node_end(node) > mm->scan_hit_start &&
714		 node->start < mm->scan_hit_end);
 
 
 
 
 
 
 
 
715}
716EXPORT_SYMBOL(drm_mm_scan_remove_block);
717
718/**
719 * drm_mm_clean - checks whether an allocator is clean
720 * @mm: drm_mm allocator to check
721 *
722 * Returns:
723 * True if the allocator is completely free, false if there's still a node
724 * allocated in it.
725 */
726bool drm_mm_clean(struct drm_mm * mm)
727{
728	struct list_head *head = &mm->head_node.node_list;
729
730	return (head->next->next == head);
731}
732EXPORT_SYMBOL(drm_mm_clean);
733
734/**
735 * drm_mm_init - initialize a drm-mm allocator
736 * @mm: the drm_mm structure to initialize
737 * @start: start of the range managed by @mm
738 * @size: end of the range managed by @mm
739 *
740 * Note that @mm must be cleared to 0 before calling this function.
741 */
742void drm_mm_init(struct drm_mm * mm, u64 start, u64 size)
743{
744	INIT_LIST_HEAD(&mm->hole_stack);
 
 
745	mm->scanned_blocks = 0;
 
746
747	/* Clever trick to avoid a special case in the free hole tracking. */
748	INIT_LIST_HEAD(&mm->head_node.node_list);
749	INIT_LIST_HEAD(&mm->head_node.hole_stack);
750	mm->head_node.hole_follows = 1;
751	mm->head_node.scanned_block = 0;
752	mm->head_node.scanned_prev_free = 0;
753	mm->head_node.scanned_next_free = 0;
754	mm->head_node.mm = mm;
755	mm->head_node.start = start + size;
756	mm->head_node.size = start - mm->head_node.start;
757	list_add_tail(&mm->head_node.hole_stack, &mm->hole_stack);
758
759	mm->color_adjust = NULL;
760}
761EXPORT_SYMBOL(drm_mm_init);
762
763/**
764 * drm_mm_takedown - clean up a drm_mm allocator
765 * @mm: drm_mm allocator to clean up
766 *
767 * Note that it is a bug to call this function on an allocator which is not
768 * clean.
769 */
770void drm_mm_takedown(struct drm_mm * mm)
771{
772	WARN(!list_empty(&mm->head_node.node_list),
773	     "Memory manager not clean during takedown.\n");
774}
775EXPORT_SYMBOL(drm_mm_takedown);
776
777static u64 drm_mm_debug_hole(struct drm_mm_node *entry,
778				     const char *prefix)
779{
780	u64 hole_start, hole_end, hole_size;
781
782	if (entry->hole_follows) {
783		hole_start = drm_mm_hole_node_start(entry);
784		hole_end = drm_mm_hole_node_end(entry);
785		hole_size = hole_end - hole_start;
786		pr_debug("%s %#llx-%#llx: %llu: free\n", prefix, hole_start,
787			 hole_end, hole_size);
788		return hole_size;
789	}
 
790
791	return 0;
792}
 
793
794/**
795 * drm_mm_debug_table - dump allocator state to dmesg
796 * @mm: drm_mm allocator to dump
797 * @prefix: prefix to use for dumping to dmesg
798 */
799void drm_mm_debug_table(struct drm_mm *mm, const char *prefix)
800{
801	struct drm_mm_node *entry;
802	u64 total_used = 0, total_free = 0, total = 0;
 
803
804	total_free += drm_mm_debug_hole(&mm->head_node, prefix);
 
 
 
 
 
 
 
805
806	drm_mm_for_each_node(entry, mm) {
807		pr_debug("%s %#llx-%#llx: %llu: used\n", prefix, entry->start,
808			 entry->start + entry->size, entry->size);
 
809		total_used += entry->size;
810		total_free += drm_mm_debug_hole(entry, prefix);
 
 
 
 
 
 
 
 
 
811	}
812	total = total_free + total_used;
813
814	pr_debug("%s total: %llu, used %llu free %llu\n", prefix, total,
815		 total_used, total_free);
816}
817EXPORT_SYMBOL(drm_mm_debug_table);
818
819#if defined(CONFIG_DEBUG_FS)
820static u64 drm_mm_dump_hole(struct seq_file *m, struct drm_mm_node *entry)
821{
822	u64 hole_start, hole_end, hole_size;
823
824	if (entry->hole_follows) {
825		hole_start = drm_mm_hole_node_start(entry);
826		hole_end = drm_mm_hole_node_end(entry);
827		hole_size = hole_end - hole_start;
828		seq_printf(m, "%#018llx-%#018llx: %llu: free\n", hole_start,
829			   hole_end, hole_size);
830		return hole_size;
831	}
832
833	return 0;
834}
835
836/**
837 * drm_mm_dump_table - dump allocator state to a seq_file
838 * @m: seq_file to dump to
839 * @mm: drm_mm allocator to dump
840 */
841int drm_mm_dump_table(struct seq_file *m, struct drm_mm *mm)
842{
843	struct drm_mm_node *entry;
844	u64 total_used = 0, total_free = 0, total = 0;
 
845
846	total_free += drm_mm_dump_hole(m, &mm->head_node);
 
 
 
 
 
 
847
848	drm_mm_for_each_node(entry, mm) {
849		seq_printf(m, "%#018llx-%#018llx: %llu: used\n", entry->start,
850			   entry->start + entry->size, entry->size);
 
851		total_used += entry->size;
852		total_free += drm_mm_dump_hole(m, entry);
 
 
 
 
 
 
 
853	}
854	total = total_free + total_used;
855
856	seq_printf(m, "total: %llu, used %llu free %llu\n", total,
857		   total_used, total_free);
858	return 0;
859}
860EXPORT_SYMBOL(drm_mm_dump_table);
861#endif