1/**************************************************************************
2 *
3 * Copyright 2006-2008 Tungsten Graphics, Inc., Cedar Park, TX. USA.
4 * Copyright 2016 Intel Corporation
5 * All Rights Reserved.
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a
8 * copy of this software and associated documentation files (the
9 * "Software"), to deal in the Software without restriction, including
10 * without limitation the rights to use, copy, modify, merge, publish,
11 * distribute, sub license, and/or sell copies of the Software, and to
12 * permit persons to whom the Software is furnished to do so, subject to
13 * the following conditions:
14 *
15 * The above copyright notice and this permission notice (including the
16 * next paragraph) shall be included in all copies or substantial portions
17 * of the Software.
18 *
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
22 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
23 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
24 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
25 * USE OR OTHER DEALINGS IN THE SOFTWARE.
26 *
27 *
28 **************************************************************************/
29/*
30 * Authors:
31 * Thomas Hellstrom <thomas-at-tungstengraphics-dot-com>
32 */
33
34#ifndef _DRM_MM_H_
35#define _DRM_MM_H_
36
37/*
38 * Generic range manager structs
39 */
40#include <linux/bug.h>
41#include <linux/rbtree.h>
42#include <linux/limits.h>
43#include <linux/mm_types.h>
44#include <linux/list.h>
45#include <linux/spinlock.h>
46#ifdef CONFIG_DRM_DEBUG_MM
47#include <linux/stackdepot.h>
48#endif
49#include <linux/types.h>
50
51#include <drm/drm_print.h>
52
53#ifdef CONFIG_DRM_DEBUG_MM
54#define DRM_MM_BUG_ON(expr) BUG_ON(expr)
55#else
56#define DRM_MM_BUG_ON(expr) BUILD_BUG_ON_INVALID(expr)
57#endif
58
59/**
60 * enum drm_mm_insert_mode - control search and allocation behaviour
61 *
62 * The &struct drm_mm range manager supports finding a suitable modes using
63 * a number of search trees. These trees are oranised by size, by address and
64 * in most recent eviction order. This allows the user to find either the
65 * smallest hole to reuse, the lowest or highest address to reuse, or simply
66 * reuse the most recent eviction that fits. When allocating the &drm_mm_node
67 * from within the hole, the &drm_mm_insert_mode also dictate whether to
68 * allocate the lowest matching address or the highest.
69 */
70enum drm_mm_insert_mode {
71 /**
72 * @DRM_MM_INSERT_BEST:
73 *
74 * Search for the smallest hole (within the search range) that fits
75 * the desired node.
76 *
77 * Allocates the node from the bottom of the found hole.
78 */
79 DRM_MM_INSERT_BEST = 0,
80
81 /**
82 * @DRM_MM_INSERT_LOW:
83 *
84 * Search for the lowest hole (address closest to 0, within the search
85 * range) that fits the desired node.
86 *
87 * Allocates the node from the bottom of the found hole.
88 */
89 DRM_MM_INSERT_LOW,
90
91 /**
92 * @DRM_MM_INSERT_HIGH:
93 *
94 * Search for the highest hole (address closest to U64_MAX, within the
95 * search range) that fits the desired node.
96 *
97 * Allocates the node from the *top* of the found hole. The specified
98 * alignment for the node is applied to the base of the node
99 * (&drm_mm_node.start).
100 */
101 DRM_MM_INSERT_HIGH,
102
103 /**
104 * @DRM_MM_INSERT_EVICT:
105 *
106 * Search for the most recently evicted hole (within the search range)
107 * that fits the desired node. This is appropriate for use immediately
108 * after performing an eviction scan (see drm_mm_scan_init()) and
109 * removing the selected nodes to form a hole.
110 *
111 * Allocates the node from the bottom of the found hole.
112 */
113 DRM_MM_INSERT_EVICT,
114
115 /**
116 * @DRM_MM_INSERT_ONCE:
117 *
118 * Only check the first hole for suitablity and report -ENOSPC
119 * immediately otherwise, rather than check every hole until a
120 * suitable one is found. Can only be used in conjunction with another
121 * search method such as DRM_MM_INSERT_HIGH or DRM_MM_INSERT_LOW.
122 */
123 DRM_MM_INSERT_ONCE = BIT(31),
124
125 /**
126 * @DRM_MM_INSERT_HIGHEST:
127 *
128 * Only check the highest hole (the hole with the largest address) and
129 * insert the node at the top of the hole or report -ENOSPC if
130 * unsuitable.
131 *
132 * Does not search all holes.
133 */
134 DRM_MM_INSERT_HIGHEST = DRM_MM_INSERT_HIGH | DRM_MM_INSERT_ONCE,
135
136 /**
137 * @DRM_MM_INSERT_LOWEST:
138 *
139 * Only check the lowest hole (the hole with the smallest address) and
140 * insert the node at the bottom of the hole or report -ENOSPC if
141 * unsuitable.
142 *
143 * Does not search all holes.
144 */
145 DRM_MM_INSERT_LOWEST = DRM_MM_INSERT_LOW | DRM_MM_INSERT_ONCE,
146};
147
148/**
149 * struct drm_mm_node - allocated block in the DRM allocator
150 *
151 * This represents an allocated block in a &drm_mm allocator. Except for
152 * pre-reserved nodes inserted using drm_mm_reserve_node() the structure is
153 * entirely opaque and should only be accessed through the provided funcions.
154 * Since allocation of these nodes is entirely handled by the driver they can be
155 * embedded.
156 */
157struct drm_mm_node {
158 /** @color: Opaque driver-private tag. */
159 unsigned long color;
160 /** @start: Start address of the allocated block. */
161 u64 start;
162 /** @size: Size of the allocated block. */
163 u64 size;
164 /* private: */
165 struct drm_mm *mm;
166 struct list_head node_list;
167 struct list_head hole_stack;
168 struct rb_node rb;
169 struct rb_node rb_hole_size;
170 struct rb_node rb_hole_addr;
171 u64 __subtree_last;
172 u64 hole_size;
173 u64 subtree_max_hole;
174 unsigned long flags;
175#define DRM_MM_NODE_ALLOCATED_BIT 0
176#define DRM_MM_NODE_SCANNED_BIT 1
177#ifdef CONFIG_DRM_DEBUG_MM
178 depot_stack_handle_t stack;
179#endif
180};
181
182/**
183 * struct drm_mm - DRM allocator
184 *
185 * DRM range allocator with a few special functions and features geared towards
186 * managing GPU memory. Except for the @color_adjust callback the structure is
187 * entirely opaque and should only be accessed through the provided functions
188 * and macros. This structure can be embedded into larger driver structures.
189 */
190struct drm_mm {
191 /**
192 * @color_adjust:
193 *
194 * Optional driver callback to further apply restrictions on a hole. The
195 * node argument points at the node containing the hole from which the
196 * block would be allocated (see drm_mm_hole_follows() and friends). The
197 * other arguments are the size of the block to be allocated. The driver
198 * can adjust the start and end as needed to e.g. insert guard pages.
199 */
200 void (*color_adjust)(const struct drm_mm_node *node,
201 unsigned long color,
202 u64 *start, u64 *end);
203
204 /* private: */
205 /* List of all memory nodes that immediately precede a free hole. */
206 struct list_head hole_stack;
207 /* head_node.node_list is the list of all memory nodes, ordered
208 * according to the (increasing) start address of the memory node. */
209 struct drm_mm_node head_node;
210 /* Keep an interval_tree for fast lookup of drm_mm_nodes by address. */
211 struct rb_root_cached interval_tree;
212 struct rb_root_cached holes_size;
213 struct rb_root holes_addr;
214
215 unsigned long scan_active;
216};
217
218/**
219 * struct drm_mm_scan - DRM allocator eviction roaster data
220 *
221 * This structure tracks data needed for the eviction roaster set up using
222 * drm_mm_scan_init(), and used with drm_mm_scan_add_block() and
223 * drm_mm_scan_remove_block(). The structure is entirely opaque and should only
224 * be accessed through the provided functions and macros. It is meant to be
225 * allocated temporarily by the driver on the stack.
226 */
227struct drm_mm_scan {
228 /* private: */
229 struct drm_mm *mm;
230
231 u64 size;
232 u64 alignment;
233 u64 remainder_mask;
234
235 u64 range_start;
236 u64 range_end;
237
238 u64 hit_start;
239 u64 hit_end;
240
241 unsigned long color;
242 enum drm_mm_insert_mode mode;
243};
244
245/**
246 * drm_mm_node_allocated - checks whether a node is allocated
247 * @node: drm_mm_node to check
248 *
249 * Drivers are required to clear a node prior to using it with the
250 * drm_mm range manager.
251 *
252 * Drivers should use this helper for proper encapsulation of drm_mm
253 * internals.
254 *
255 * Returns:
256 * True if the @node is allocated.
257 */
258static inline bool drm_mm_node_allocated(const struct drm_mm_node *node)
259{
260 return test_bit(DRM_MM_NODE_ALLOCATED_BIT, &node->flags);
261}
262
263/**
264 * drm_mm_initialized - checks whether an allocator is initialized
265 * @mm: drm_mm to check
266 *
267 * Drivers should clear the struct drm_mm prior to initialisation if they
268 * want to use this function.
269 *
270 * Drivers should use this helper for proper encapsulation of drm_mm
271 * internals.
272 *
273 * Returns:
274 * True if the @mm is initialized.
275 */
276static inline bool drm_mm_initialized(const struct drm_mm *mm)
277{
278 return READ_ONCE(mm->hole_stack.next);
279}
280
281/**
282 * drm_mm_hole_follows - checks whether a hole follows this node
283 * @node: drm_mm_node to check
284 *
285 * Holes are embedded into the drm_mm using the tail of a drm_mm_node.
286 * If you wish to know whether a hole follows this particular node,
287 * query this function. See also drm_mm_hole_node_start() and
288 * drm_mm_hole_node_end().
289 *
290 * Returns:
291 * True if a hole follows the @node.
292 */
293static inline bool drm_mm_hole_follows(const struct drm_mm_node *node)
294{
295 return node->hole_size;
296}
297
298static inline u64 __drm_mm_hole_node_start(const struct drm_mm_node *hole_node)
299{
300 return hole_node->start + hole_node->size;
301}
302
303/**
304 * drm_mm_hole_node_start - computes the start of the hole following @node
305 * @hole_node: drm_mm_node which implicitly tracks the following hole
306 *
307 * This is useful for driver-specific debug dumpers. Otherwise drivers should
308 * not inspect holes themselves. Drivers must check first whether a hole indeed
309 * follows by looking at drm_mm_hole_follows()
310 *
311 * Returns:
312 * Start of the subsequent hole.
313 */
314static inline u64 drm_mm_hole_node_start(const struct drm_mm_node *hole_node)
315{
316 DRM_MM_BUG_ON(!drm_mm_hole_follows(hole_node));
317 return __drm_mm_hole_node_start(hole_node);
318}
319
320static inline u64 __drm_mm_hole_node_end(const struct drm_mm_node *hole_node)
321{
322 return list_next_entry(hole_node, node_list)->start;
323}
324
325/**
326 * drm_mm_hole_node_end - computes the end of the hole following @node
327 * @hole_node: drm_mm_node which implicitly tracks the following hole
328 *
329 * This is useful for driver-specific debug dumpers. Otherwise drivers should
330 * not inspect holes themselves. Drivers must check first whether a hole indeed
331 * follows by looking at drm_mm_hole_follows().
332 *
333 * Returns:
334 * End of the subsequent hole.
335 */
336static inline u64 drm_mm_hole_node_end(const struct drm_mm_node *hole_node)
337{
338 return __drm_mm_hole_node_end(hole_node);
339}
340
341/**
342 * drm_mm_nodes - list of nodes under the drm_mm range manager
343 * @mm: the struct drm_mm range manager
344 *
345 * As the drm_mm range manager hides its node_list deep with its
346 * structure, extracting it looks painful and repetitive. This is
347 * not expected to be used outside of the drm_mm_for_each_node()
348 * macros and similar internal functions.
349 *
350 * Returns:
351 * The node list, may be empty.
352 */
353#define drm_mm_nodes(mm) (&(mm)->head_node.node_list)
354
355/**
356 * drm_mm_for_each_node - iterator to walk over all allocated nodes
357 * @entry: &struct drm_mm_node to assign to in each iteration step
358 * @mm: &drm_mm allocator to walk
359 *
360 * This iterator walks over all nodes in the range allocator. It is implemented
361 * with list_for_each(), so not save against removal of elements.
362 */
363#define drm_mm_for_each_node(entry, mm) \
364 list_for_each_entry(entry, drm_mm_nodes(mm), node_list)
365
366/**
367 * drm_mm_for_each_node_safe - iterator to walk over all allocated nodes
368 * @entry: &struct drm_mm_node to assign to in each iteration step
369 * @next: &struct drm_mm_node to store the next step
370 * @mm: &drm_mm allocator to walk
371 *
372 * This iterator walks over all nodes in the range allocator. It is implemented
373 * with list_for_each_safe(), so save against removal of elements.
374 */
375#define drm_mm_for_each_node_safe(entry, next, mm) \
376 list_for_each_entry_safe(entry, next, drm_mm_nodes(mm), node_list)
377
378/**
379 * drm_mm_for_each_hole - iterator to walk over all holes
380 * @pos: &drm_mm_node used internally to track progress
381 * @mm: &drm_mm allocator to walk
382 * @hole_start: ulong variable to assign the hole start to on each iteration
383 * @hole_end: ulong variable to assign the hole end to on each iteration
384 *
385 * This iterator walks over all holes in the range allocator. It is implemented
386 * with list_for_each(), so not save against removal of elements. @entry is used
387 * internally and will not reflect a real drm_mm_node for the very first hole.
388 * Hence users of this iterator may not access it.
389 *
390 * Implementation Note:
391 * We need to inline list_for_each_entry in order to be able to set hole_start
392 * and hole_end on each iteration while keeping the macro sane.
393 */
394#define drm_mm_for_each_hole(pos, mm, hole_start, hole_end) \
395 for (pos = list_first_entry(&(mm)->hole_stack, \
396 typeof(*pos), hole_stack); \
397 &pos->hole_stack != &(mm)->hole_stack ? \
398 hole_start = drm_mm_hole_node_start(pos), \
399 hole_end = hole_start + pos->hole_size, \
400 1 : 0; \
401 pos = list_next_entry(pos, hole_stack))
402
403/*
404 * Basic range manager support (drm_mm.c)
405 */
406int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node);
407int drm_mm_insert_node_in_range(struct drm_mm *mm,
408 struct drm_mm_node *node,
409 u64 size,
410 u64 alignment,
411 unsigned long color,
412 u64 start,
413 u64 end,
414 enum drm_mm_insert_mode mode);
415
416/**
417 * drm_mm_insert_node_generic - search for space and insert @node
418 * @mm: drm_mm to allocate from
419 * @node: preallocate node to insert
420 * @size: size of the allocation
421 * @alignment: alignment of the allocation
422 * @color: opaque tag value to use for this node
423 * @mode: fine-tune the allocation search and placement
424 *
425 * This is a simplified version of drm_mm_insert_node_in_range() with no
426 * range restrictions applied.
427 *
428 * The preallocated node must be cleared to 0.
429 *
430 * Returns:
431 * 0 on success, -ENOSPC if there's no suitable hole.
432 */
433static inline int
434drm_mm_insert_node_generic(struct drm_mm *mm, struct drm_mm_node *node,
435 u64 size, u64 alignment,
436 unsigned long color,
437 enum drm_mm_insert_mode mode)
438{
439 return drm_mm_insert_node_in_range(mm, node,
440 size, alignment, color,
441 0, U64_MAX, mode);
442}
443
444/**
445 * drm_mm_insert_node - search for space and insert @node
446 * @mm: drm_mm to allocate from
447 * @node: preallocate node to insert
448 * @size: size of the allocation
449 *
450 * This is a simplified version of drm_mm_insert_node_generic() with @color set
451 * to 0.
452 *
453 * The preallocated node must be cleared to 0.
454 *
455 * Returns:
456 * 0 on success, -ENOSPC if there's no suitable hole.
457 */
458static inline int drm_mm_insert_node(struct drm_mm *mm,
459 struct drm_mm_node *node,
460 u64 size)
461{
462 return drm_mm_insert_node_generic(mm, node, size, 0, 0, 0);
463}
464
465void drm_mm_remove_node(struct drm_mm_node *node);
466void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new);
467void drm_mm_init(struct drm_mm *mm, u64 start, u64 size);
468void drm_mm_takedown(struct drm_mm *mm);
469
470/**
471 * drm_mm_clean - checks whether an allocator is clean
472 * @mm: drm_mm allocator to check
473 *
474 * Returns:
475 * True if the allocator is completely free, false if there's still a node
476 * allocated in it.
477 */
478static inline bool drm_mm_clean(const struct drm_mm *mm)
479{
480 return list_empty(drm_mm_nodes(mm));
481}
482
483struct drm_mm_node *
484__drm_mm_interval_first(const struct drm_mm *mm, u64 start, u64 last);
485
486/**
487 * drm_mm_for_each_node_in_range - iterator to walk over a range of
488 * allocated nodes
489 * @node__: drm_mm_node structure to assign to in each iteration step
490 * @mm__: drm_mm allocator to walk
491 * @start__: starting offset, the first node will overlap this
492 * @end__: ending offset, the last node will start before this (but may overlap)
493 *
494 * This iterator walks over all nodes in the range allocator that lie
495 * between @start and @end. It is implemented similarly to list_for_each(),
496 * but using the internal interval tree to accelerate the search for the
497 * starting node, and so not safe against removal of elements. It assumes
498 * that @end is within (or is the upper limit of) the drm_mm allocator.
499 * If [@start, @end] are beyond the range of the drm_mm, the iterator may walk
500 * over the special _unallocated_ &drm_mm.head_node, and may even continue
501 * indefinitely.
502 */
503#define drm_mm_for_each_node_in_range(node__, mm__, start__, end__) \
504 for (node__ = __drm_mm_interval_first((mm__), (start__), (end__)-1); \
505 node__->start < (end__); \
506 node__ = list_next_entry(node__, node_list))
507
508void drm_mm_scan_init_with_range(struct drm_mm_scan *scan,
509 struct drm_mm *mm,
510 u64 size, u64 alignment, unsigned long color,
511 u64 start, u64 end,
512 enum drm_mm_insert_mode mode);
513
514/**
515 * drm_mm_scan_init - initialize lru scanning
516 * @scan: scan state
517 * @mm: drm_mm to scan
518 * @size: size of the allocation
519 * @alignment: alignment of the allocation
520 * @color: opaque tag value to use for the allocation
521 * @mode: fine-tune the allocation search and placement
522 *
523 * This is a simplified version of drm_mm_scan_init_with_range() with no range
524 * restrictions applied.
525 *
526 * This simply sets up the scanning routines with the parameters for the desired
527 * hole.
528 *
529 * Warning:
530 * As long as the scan list is non-empty, no other operations than
531 * adding/removing nodes to/from the scan list are allowed.
532 */
533static inline void drm_mm_scan_init(struct drm_mm_scan *scan,
534 struct drm_mm *mm,
535 u64 size,
536 u64 alignment,
537 unsigned long color,
538 enum drm_mm_insert_mode mode)
539{
540 drm_mm_scan_init_with_range(scan, mm,
541 size, alignment, color,
542 0, U64_MAX, mode);
543}
544
545bool drm_mm_scan_add_block(struct drm_mm_scan *scan,
546 struct drm_mm_node *node);
547bool drm_mm_scan_remove_block(struct drm_mm_scan *scan,
548 struct drm_mm_node *node);
549struct drm_mm_node *drm_mm_scan_color_evict(struct drm_mm_scan *scan);
550
551void drm_mm_print(const struct drm_mm *mm, struct drm_printer *p);
552
553#endif
554

source code of linux/include/drm/drm_mm.h