usr/src/uts/common/io/drm/drm_mm.c

   1 /*
   2  *
   3  * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., USA.
   4  * Copyright (c) 2009, 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 /*
  31  * Generic simple memory manager implementation. Intended to be used as a base
  32  * class implementation for more advanced memory managers.
  33  *
  34  * Note that the algorithm used is quite simple and there might be substantial
  35  * performance gains if a smarter free list is implemented.
  36  * Currently it is just an
  37  * unordered stack of free regions. This could easily be improved if an RB-tree
  38  * is used instead. At least if we expect heavy fragmentation.
  39  *
  40  * Aligned allocations can also see improvement.
  41  *
  42  * Authors:
  43  * Thomas HellstrÃ¶m <thomas-at-tungstengraphics-dot-com>
  44  */
  45
  46 /*
  47  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  48  * Use is subject to license terms.
  49  */
  50
  51 #include "drmP.h"
  52
  53 unsigned long
  54 drm_mm_tail_space(struct drm_mm *mm)
  55 {
  56         struct list_head *tail_node;
  57         struct drm_mm_node *entry;
  58
  59         tail_node = mm->ml_entry.prev;
  60         entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
  61         if (!entry->free)
  62                 return (0);
  63
  64         return (entry->size);
  65 }
  66
  67 int
  68 drm_mm_remove_space_from_tail(struct drm_mm *mm, unsigned long size)
  69 {
  70         struct list_head *tail_node;
  71         struct drm_mm_node *entry;
  72
  73         tail_node = mm->ml_entry.prev;
  74         entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
  75         if (!entry->free)
  76                 return (ENOMEM);
  77
  78         if (entry->size <= size)
  79                 return (ENOMEM);
  80
  81         entry->size -= size;
  82         return (0);
  83 }
  84
  85
  86 static int
  87 drm_mm_create_tail_node(struct drm_mm *mm,
  88                     unsigned long start,
  89                     unsigned long size)
  90 {
  91         struct drm_mm_node *child;
  92
  93         child = (struct drm_mm_node *)
  94             drm_alloc(sizeof (*child), DRM_MEM_MM);
  95         if (!child)
  96                 return (ENOMEM);
  97
  98         child->free = 1;
  99         child->size = size;
 100         child->start = start;
 101         child->mm = mm;
 102
 103         list_add_tail(&child->ml_entry, &mm->ml_entry, (caddr_t)child);
 104         list_add_tail(&child->fl_entry, &mm->fl_entry, (caddr_t)child);
 105
 106         return (0);
 107 }
 108
 109
 110 int
 111 drm_mm_add_space_to_tail(struct drm_mm *mm, unsigned long size)
 112 {
 113         struct list_head *tail_node;
 114         struct drm_mm_node *entry;
 115
 116         tail_node = mm->ml_entry.prev;
 117         entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
 118         if (!entry->free) {
 119                 return (drm_mm_create_tail_node(mm,
 120                     entry->start + entry->size, size));
 121         }
 122         entry->size += size;
 123         return (0);
 124 }
 125
 126 static struct drm_mm_node *
 127 drm_mm_split_at_start(struct drm_mm_node *parent,
 128                     unsigned long size)
 129 {
 130         struct drm_mm_node *child;
 131
 132         child = (struct drm_mm_node *)
 133             drm_alloc(sizeof (*child), DRM_MEM_MM);
 134         if (!child)
 135                 return (NULL);
 136
 137         INIT_LIST_HEAD(&child->fl_entry);
 138
 139         child->free = 0;
 140         child->size = size;
 141         child->start = parent->start;
 142         child->mm = parent->mm;
 143
 144         list_add_tail(&child->ml_entry, &parent->ml_entry, (caddr_t)child);
 145         INIT_LIST_HEAD(&child->fl_entry);
 146
 147         parent->size -= size;
 148         parent->start += size;
 149         return (child);
 150 }
 151
 152 /*
 153  * Put a block. Merge with the previous and / or next block if they are free.
 154  * Otherwise add to the free stack.
 155  */
 156
 157 void
 158 drm_mm_put_block(struct drm_mm_node *cur)
 159 {
 160
 161         struct drm_mm *mm = cur->mm;
 162         struct list_head *cur_head = &cur->ml_entry;
 163         struct list_head *root_head = &mm->ml_entry;
 164         struct drm_mm_node *prev_node = NULL;
 165         struct drm_mm_node *next_node;
 166
 167         int merged = 0;
 168
 169         if (cur_head->prev != root_head) {
 170                 prev_node = list_entry(cur_head->prev,
 171                     struct drm_mm_node, ml_entry);
 172                 if (prev_node->free) {
 173                         prev_node->size += cur->size;
 174                         merged = 1;
 175                 }
 176         }
 177         if (cur_head->next != root_head) {
 178                 next_node = list_entry(cur_head->next,
 179                     struct drm_mm_node, ml_entry);
 180                 if (next_node->free) {
 181                         if (merged) {
 182                                 prev_node->size += next_node->size;
 183                                 list_del(&next_node->ml_entry);
 184                                 list_del(&next_node->fl_entry);
 185                                 drm_free(next_node,
 186                                     sizeof (*next_node), DRM_MEM_MM);
 187                         } else {
 188                                 next_node->size += cur->size;
 189                                 next_node->start = cur->start;
 190                                 merged = 1;
 191                         }
 192                 }
 193         }
 194         if (!merged) {
 195                 cur->free = 1;
 196                 list_add(&cur->fl_entry, &mm->fl_entry, (caddr_t)cur);
 197         } else {
 198                 list_del(&cur->ml_entry);
 199                 drm_free(cur, sizeof (*cur), DRM_MEM_MM);
 200         }
 201 }
 202
 203 struct drm_mm_node *
 204 drm_mm_get_block(struct drm_mm_node *parent,
 205                     unsigned long size,
 206                     unsigned alignment)
 207 {
 208
 209         struct drm_mm_node *align_splitoff = NULL;
 210         struct drm_mm_node *child;
 211         unsigned tmp = 0;
 212
 213         if (alignment)
 214                 tmp = parent->start % alignment;
 215
 216         if (tmp) {
 217                 align_splitoff = drm_mm_split_at_start(parent, alignment - tmp);
 218                 if (!align_splitoff)
 219                         return (NULL);
 220         }
 221
 222         if (parent->size == size) {
 223                 list_del_init(&parent->fl_entry);
 224                 parent->free = 0;
 225                 return (parent);
 226         } else {
 227                 child = drm_mm_split_at_start(parent, size);
 228         }
 229
 230         if (align_splitoff)
 231                 drm_mm_put_block(align_splitoff);
 232
 233         return (child);
 234 }
 235
 236 struct drm_mm_node *
 237 drm_mm_search_free(const struct drm_mm *mm,
 238                     unsigned long size,
 239                     unsigned alignment,
 240                     int best_match)
 241 {
 242         struct list_head *list;
 243         const struct list_head *free_stack = &mm->fl_entry;
 244         struct drm_mm_node *entry;
 245         struct drm_mm_node *best;
 246         unsigned long best_size;
 247         unsigned wasted;
 248
 249         best = NULL;
 250         best_size = ~0UL;
 251
 252         list_for_each(list, free_stack) {
 253                 entry = list_entry(list, struct drm_mm_node, fl_entry);
 254                 wasted = 0;
 255
 256                 if (entry->size < size)
 257                         continue;
 258
 259                 if (alignment) {
 260                         register unsigned tmp = entry->start % alignment;
 261                         if (tmp)
 262                                 wasted += alignment - tmp;
 263                 }
 264
 265
 266                 if (entry->size >= size + wasted) {
 267                         if (!best_match)
 268                                 return (entry);
 269                         if (size < best_size) {
 270                                 best = entry;
 271                                 best_size = entry->size;
 272                         }
 273                 }
 274         }
 275
 276         return (best);
 277 }
 278
 279 int
 280 drm_mm_clean(struct drm_mm *mm)
 281 {
 282         struct list_head *head = &mm->ml_entry;
 283
 284         return (head->next->next == head);
 285 }
 286
 287 int
 288 drm_mm_init(struct drm_mm *mm, unsigned long start, unsigned long size)
 289 {
 290         INIT_LIST_HEAD(&mm->ml_entry);
 291         INIT_LIST_HEAD(&mm->fl_entry);
 292
 293         return (drm_mm_create_tail_node(mm, start, size));
 294 }
 295
 296
 297 void
 298 drm_mm_takedown(struct drm_mm *mm)
 299 {
 300         struct list_head *bnode = mm->fl_entry.next;
 301         struct drm_mm_node *entry;
 302
 303         entry = list_entry(bnode, struct drm_mm_node, fl_entry);
 304
 305         if (entry->ml_entry.next != &mm->ml_entry ||
 306             entry->fl_entry.next != &mm->fl_entry) {
 307                 DRM_ERROR("Memory manager not clean. Delaying takedown\n");
 308                 return;
 309         }
 310
 311         list_del(&entry->fl_entry);
 312         list_del(&entry->ml_entry);
 313
 314         drm_free(entry, sizeof (*entry), DRM_MEM_MM);
 315 }
 316
 317 void
 318 drm_mm_clean_ml(const struct drm_mm *mm)
 319 {
 320         const struct list_head *mlstack = &mm->ml_entry;
 321         struct list_head *list, *temp;
 322         struct drm_mm_node *entry;
 323
 324         if (mlstack->next == NULL)
 325                 return;
 326
 327         list_for_each_safe(list, temp, mlstack) {
 328                 entry = list_entry(list, struct drm_mm_node, ml_entry);
 329                 DRM_DEBUG("ml_entry 0x%x, size 0x%x, start 0x%x",
 330                     entry, entry->size, entry->start);
 331
 332                 list_del(&entry->fl_entry);
 333                 list_del(&entry->ml_entry);
 334                 drm_free(entry, sizeof (*entry), DRM_MEM_MM);
 335         }
 336 }