drivers/char/drm/i915_mem.c

   1 /* i915_mem.c -- Simple agp/fb memory manager for i915 -*- linux-c -*-
   2  */
   3 /**************************************************************************
   4  *
   5  * Copyright 2003 Tungsten Graphics, Inc., Cedar Park, Texas.
   6  * All Rights Reserved.
   7  *
   8  **************************************************************************/
   9
  10 #include "drmP.h"
  11 #include "drm.h"
  12 #include "i915_drm.h"
  13 #include "i915_drv.h"
  14
  15 /* This memory manager is integrated into the global/local lru
  16  * mechanisms used by the clients.  Specifically, it operates by
  17  * setting the 'in_use' fields of the global LRU to indicate whether
  18  * this region is privately allocated to a client.
  19  *
  20  * This does require the client to actually respect that field.
  21  *
  22  * Currently no effort is made to allocate 'private' memory in any
  23  * clever way - the LRU information isn't used to determine which
  24  * block to allocate, and the ring is drained prior to allocations --
  25  * in other words allocation is expensive.
  26  */
  27 static void mark_block(drm_device_t * dev, struct mem_block *p, int in_use)
  28 {
  29         drm_i915_private_t *dev_priv = dev->dev_private;
  30         drm_i915_sarea_t *sarea_priv = dev_priv->sarea_priv;
  31         drm_tex_region_t *list;
  32         unsigned shift, nr;
  33         unsigned start;
  34         unsigned end;
  35         unsigned i;
  36         int age;
  37
  38         shift = dev_priv->tex_lru_log_granularity;
  39         nr = I915_NR_TEX_REGIONS;
  40
  41         start = p->start >> shift;
  42         end = (p->start + p->size - 1) >> shift;
  43
  44         age = ++sarea_priv->texAge;
  45         list = sarea_priv->texList;
  46
  47         /* Mark the regions with the new flag and update their age.  Move
  48          * them to head of list to preserve LRU semantics.
  49          */
  50         for (i = start; i <= end; i++) {
  51                 list[i].in_use = in_use;
  52                 list[i].age = age;
  53
  54                 /* remove_from_list(i)
  55                  */
  56                 list[(unsigned)list[i].next].prev = list[i].prev;
  57                 list[(unsigned)list[i].prev].next = list[i].next;
  58
  59                 /* insert_at_head(list, i)
  60                  */
  61                 list[i].prev = nr;
  62                 list[i].next = list[nr].next;
  63                 list[(unsigned)list[nr].next].prev = i;
  64                 list[nr].next = i;
  65         }
  66 }
  67
  68 /* Very simple allocator for agp memory, working on a static range
  69  * already mapped into each client's address space.
  70  */
  71
  72 static struct mem_block *split_block(struct mem_block *p, int start, int size,
  73                                      DRMFILE filp)
  74 {
  75         /* Maybe cut off the start of an existing block */
  76         if (start > p->start) {
  77                 struct mem_block *newblock = drm_alloc(sizeof(*newblock), DRM_MEM_BUFLISTS);
  78                 if (!newblock)
  79                         goto out;
  80                 newblock->start = start;
  81                 newblock->size = p->size - (start - p->start);
  82                 newblock->filp = NULL;
  83                 newblock->next = p->next;
  84                 newblock->prev = p;
  85                 p->next->prev = newblock;
  86                 p->next = newblock;
  87                 p->size -= newblock->size;
  88                 p = newblock;
  89         }
  90
  91         /* Maybe cut off the end of an existing block */
  92         if (size < p->size) {
  93                 struct mem_block *newblock = drm_alloc(sizeof(*newblock), DRM_MEM_BUFLISTS);
  94                 if (!newblock)
  95                         goto out;
  96                 newblock->start = start + size;
  97                 newblock->size = p->size - size;
  98                 newblock->filp = NULL;
  99                 newblock->next = p->next;
 100                 newblock->prev = p;
 101                 p->next->prev = newblock;
 102                 p->next = newblock;
 103                 p->size = size;
 104         }
 105
 106       out:
 107         /* Our block is in the middle */
 108         p->filp = filp;
 109         return p;
 110 }
 111
 112 static struct mem_block *alloc_block(struct mem_block *heap, int size,
 113                                      int align2, DRMFILE filp)
 114 {
 115         struct mem_block *p;
 116         int mask = (1 << align2) - 1;
 117
 118         for (p = heap->next; p != heap; p = p->next) {
 119                 int start = (p->start + mask) & ~mask;
 120                 if (p->filp == NULL && start + size <= p->start + p->size)
 121                         return split_block(p, start, size, filp);
 122         }
 123
 124         return NULL;
 125 }
 126
 127 static struct mem_block *find_block(struct mem_block *heap, int start)
 128 {
 129         struct mem_block *p;
 130
 131         for (p = heap->next; p != heap; p = p->next)
 132                 if (p->start == start)
 133                         return p;
 134
 135         return NULL;
 136 }
 137
 138 static void free_block(struct mem_block *p)
 139 {
 140         p->filp = NULL;
 141
 142         /* Assumes a single contiguous range.  Needs a special filp in
 143          * 'heap' to stop it being subsumed.
 144          */
 145         if (p->next->filp == NULL) {
 146                 struct mem_block *q = p->next;
 147                 p->size += q->size;
 148                 p->next = q->next;
 149                 p->next->prev = p;
 150                 drm_free(q, sizeof(*q), DRM_MEM_BUFLISTS);
 151         }
 152
 153         if (p->prev->filp == NULL) {
 154                 struct mem_block *q = p->prev;
 155                 q->size += p->size;
 156                 q->next = p->next;
 157                 q->next->prev = q;
 158                 drm_free(p, sizeof(*q), DRM_MEM_BUFLISTS);
 159         }
 160 }
 161
 162 /* Initialize.  How to check for an uninitialized heap?
 163  */
 164 static int init_heap(struct mem_block **heap, int start, int size)
 165 {
 166         struct mem_block *blocks = drm_alloc(sizeof(*blocks), DRM_MEM_BUFLISTS);
 167
 168         if (!blocks)
 169                 return -ENOMEM;
 170
 171         *heap = drm_alloc(sizeof(**heap), DRM_MEM_BUFLISTS);
 172         if (!*heap) {
 173                 drm_free(blocks, sizeof(*blocks), DRM_MEM_BUFLISTS);
 174                 return -ENOMEM;
 175         }
 176
 177         blocks->start = start;
 178         blocks->size = size;
 179         blocks->filp = NULL;
 180         blocks->next = blocks->prev = *heap;
 181
 182         memset(*heap, 0, sizeof(**heap));
 183         (*heap)->filp = (DRMFILE) - 1;
 184         (*heap)->next = (*heap)->prev = blocks;
 185         return 0;
 186 }
 187
 188 /* Free all blocks associated with the releasing file.
 189  */
 190 void i915_mem_release(drm_device_t * dev, DRMFILE filp, struct mem_block *heap)
 191 {
 192         struct mem_block *p;
 193
 194         if (!heap || !heap->next)
 195                 return;
 196
 197         for (p = heap->next; p != heap; p = p->next) {
 198                 if (p->filp == filp) {
 199                         p->filp = NULL;
 200                         mark_block(dev, p, 0);
 201                 }
 202         }
 203
 204         /* Assumes a single contiguous range.  Needs a special filp in
 205          * 'heap' to stop it being subsumed.
 206          */
 207         for (p = heap->next; p != heap; p = p->next) {
 208                 while (p->filp == NULL && p->next->filp == NULL) {
 209                         struct mem_block *q = p->next;
 210                         p->size += q->size;
 211                         p->next = q->next;
 212                         p->next->prev = p;
 213                         drm_free(q, sizeof(*q), DRM_MEM_BUFLISTS);
 214                 }
 215         }
 216 }
 217
 218 /* Shutdown.
 219  */
 220 void i915_mem_takedown(struct mem_block **heap)
 221 {
 222         struct mem_block *p;
 223
 224         if (!*heap)
 225                 return;
 226
 227         for (p = (*heap)->next; p != *heap;) {
 228                 struct mem_block *q = p;
 229                 p = p->next;
 230                 drm_free(q, sizeof(*q), DRM_MEM_BUFLISTS);
 231         }
 232
 233         drm_free(*heap, sizeof(**heap), DRM_MEM_BUFLISTS);
 234         *heap = NULL;
 235 }
 236
 237 static struct mem_block **get_heap(drm_i915_private_t * dev_priv, int region)
 238 {
 239         switch (region) {
 240         case I915_MEM_REGION_AGP:
 241                 return &dev_priv->agp_heap;
 242         default:
 243                 return NULL;
 244         }
 245 }
 246
 247 /* IOCTL HANDLERS */
 248
 249 int i915_mem_alloc(DRM_IOCTL_ARGS)
 250 {
 251         DRM_DEVICE;
 252         drm_i915_private_t *dev_priv = dev->dev_private;
 253         drm_i915_mem_alloc_t alloc;
 254         struct mem_block *block, **heap;
 255
 256         if (!dev_priv) {
 257                 DRM_ERROR("%s called with no initialization\n", __FUNCTION__);
 258                 return DRM_ERR(EINVAL);
 259         }
 260
 261         DRM_COPY_FROM_USER_IOCTL(alloc, (drm_i915_mem_alloc_t __user *) data,
 262                                  sizeof(alloc));
 263
 264         heap = get_heap(dev_priv, alloc.region);
 265         if (!heap || !*heap)
 266                 return DRM_ERR(EFAULT);
 267
 268         /* Make things easier on ourselves: all allocations at least
 269          * 4k aligned.
 270          */
 271         if (alloc.alignment < 12)
 272                 alloc.alignment = 12;
 273
 274         block = alloc_block(*heap, alloc.size, alloc.alignment, filp);
 275
 276         if (!block)
 277                 return DRM_ERR(ENOMEM);
 278
 279         mark_block(dev, block, 1);
 280
 281         if (DRM_COPY_TO_USER(alloc.region_offset, &block->start, sizeof(int))) {
 282                 DRM_ERROR("copy_to_user\n");
 283                 return DRM_ERR(EFAULT);
 284         }
 285
 286         return 0;
 287 }
 288
 289 int i915_mem_free(DRM_IOCTL_ARGS)
 290 {
 291         DRM_DEVICE;
 292         drm_i915_private_t *dev_priv = dev->dev_private;
 293         drm_i915_mem_free_t memfree;
 294         struct mem_block *block, **heap;
 295
 296         if (!dev_priv) {
 297                 DRM_ERROR("%s called with no initialization\n", __FUNCTION__);
 298                 return DRM_ERR(EINVAL);
 299         }
 300
 301         DRM_COPY_FROM_USER_IOCTL(memfree, (drm_i915_mem_free_t __user *) data,
 302                                  sizeof(memfree));
 303
 304         heap = get_heap(dev_priv, memfree.region);
 305         if (!heap || !*heap)
 306                 return DRM_ERR(EFAULT);
 307
 308         block = find_block(*heap, memfree.region_offset);
 309         if (!block)
 310                 return DRM_ERR(EFAULT);
 311
 312         if (block->filp != filp)
 313                 return DRM_ERR(EPERM);
 314
 315         mark_block(dev, block, 0);
 316         free_block(block);
 317         return 0;
 318 }
 319
 320 int i915_mem_init_heap(DRM_IOCTL_ARGS)
 321 {
 322         DRM_DEVICE;
 323         drm_i915_private_t *dev_priv = dev->dev_private;
 324         drm_i915_mem_init_heap_t initheap;
 325         struct mem_block **heap;
 326
 327         if (!dev_priv) {
 328                 DRM_ERROR("%s called with no initialization\n", __FUNCTION__);
 329                 return DRM_ERR(EINVAL);
 330         }
 331
 332         DRM_COPY_FROM_USER_IOCTL(initheap,
 333                                  (drm_i915_mem_init_heap_t __user *) data,
 334                                  sizeof(initheap));
 335
 336         heap = get_heap(dev_priv, initheap.region);
 337         if (!heap)
 338                 return DRM_ERR(EFAULT);
 339
 340         if (*heap) {
 341                 DRM_ERROR("heap already initialized?");
 342                 return DRM_ERR(EFAULT);
 343         }
 344
 345         return init_heap(heap, initheap.start, initheap.size);
 346 }