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
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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  */
70 enum 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  */
157 struct 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  */
190 struct 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  */
227 struct 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  */
drm_mm_node_allocated(const struct drm_mm_node * node)258 static 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  */
drm_mm_initialized(const struct drm_mm * mm)276 static 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  */
drm_mm_hole_follows(const struct drm_mm_node * node)293 static inline bool drm_mm_hole_follows(const struct drm_mm_node *node)
294 {
295 	return node->hole_size;
296 }
297 
__drm_mm_hole_node_start(const struct drm_mm_node * hole_node)298 static 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  */
drm_mm_hole_node_start(const struct drm_mm_node * hole_node)314 static 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 
__drm_mm_hole_node_end(const struct drm_mm_node * hole_node)320 static 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  */
drm_mm_hole_node_end(const struct drm_mm_node * hole_node)336 static 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  */
406 int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node);
407 int 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  */
433 static inline int
drm_mm_insert_node_generic(struct drm_mm * mm,struct drm_mm_node * node,u64 size,u64 alignment,unsigned long color,enum drm_mm_insert_mode mode)434 drm_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  */
drm_mm_insert_node(struct drm_mm * mm,struct drm_mm_node * node,u64 size)458 static 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 
465 void drm_mm_remove_node(struct drm_mm_node *node);
466 void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new);
467 void drm_mm_init(struct drm_mm *mm, u64 start, u64 size);
468 void 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  */
drm_mm_clean(const struct drm_mm * mm)478 static inline bool drm_mm_clean(const struct drm_mm *mm)
479 {
480 	return list_empty(drm_mm_nodes(mm));
481 }
482 
483 struct 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 
508 void 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  */
drm_mm_scan_init(struct drm_mm_scan * scan,struct drm_mm * mm,u64 size,u64 alignment,unsigned long color,enum drm_mm_insert_mode mode)533 static 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 
545 bool drm_mm_scan_add_block(struct drm_mm_scan *scan,
546 			   struct drm_mm_node *node);
547 bool drm_mm_scan_remove_block(struct drm_mm_scan *scan,
548 			      struct drm_mm_node *node);
549 struct drm_mm_node *drm_mm_scan_color_evict(struct drm_mm_scan *scan);
550 
551 void drm_mm_print(const struct drm_mm *mm, struct drm_printer *p);
552 
553 #endif
554