include/drm/drm_mm.h

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