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