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 "i915.h"
  11 #include "drmP.h"
  12 #include "drm.h"
  13 #include "i915_drm.h"
  14 #include "i915_drv.h"
  15
  16 /* This memory manager is integrated into the global/local lru
  17  * mechanisms used by the clients.  Specifically, it operates by
  18  * setting the 'in_use' fields of the global LRU to indicate whether
  19  * this region is privately allocated to a client.
  20  *
  21  * This does require the client to actually respect that field.
  22  *
  23  * Currently no effort is made to allocate 'private' memory in any
  24  * clever way - the LRU information isn't used to determine which
  25  * block to allocate, and the ring is drained prior to allocations --
  26  * in other words allocation is expensive.
  27  */
  28 static void mark_block(drm_device_t * dev, struct mem_block *p, int in_use)
  29 {
  30         drm_i915_private_t *dev_priv = dev->dev_private;
  31         drm_i915_sarea_t *sarea_priv = dev_priv->sarea_priv;
  32         drm_tex_region_t *list;
  33         unsigned shift, nr;
  34         unsigned start;
  35         unsigned end;
  36         unsigned i;
  37         int age;
  38
  39         shift = dev_priv->tex_lru_log_granularity;
  40         nr = I915_NR_TEX_REGIONS;
  41
  42         start = p->start >> shift;
  43         end = (p->start + p->size - 1) >> shift;
  44
  45         age = ++sarea_priv->texAge;
  46         list = sarea_priv->texList;
  47
  48         /* Mark the regions with the new flag and update their age.  Move
  49          * them to head of list to preserve LRU semantics.
  50          */
  51         for (i = start; i <= end; i++) {
  52                 list[i].in_use = in_use;
  53                 list[i].age = age;
  54
  55                 /* remove_from_list(i)
  56                  */
  57                 list[(unsigned)list[i].next].prev = list[i].prev;
  58                 list[(unsigned)list[i].prev].next = list[i].next;
  59
  60                 /* insert_at_head(list, i)
  61                  */
  62                 list[i].prev = nr;
  63                 list[i].next = list[nr].next;
  64                 list[(unsigned)list[nr].next].prev = i;
  65                 list[nr].next = i;
  66         }
  67 }
  68
  69 /* Very simple allocator for agp memory, working on a static range
  70  * already mapped into each client's address space.
  71  */
  72
  73 static struct mem_block *split_block(struct mem_block *p, int start, int size,
  74                                      DRMFILE filp)
  75 {
  76         /* Maybe cut off the start of an existing block */
  77         if (start > p->start) {
  78                 struct mem_block *newblock = DRM_MALLOC(sizeof(*newblock));
  79                 if (!newblock)
  80                         goto out;
  81                 newblock->start = start;
  82                 newblock->size = p->size - (start - p->start);
  83                 newblock->filp = NULL;
  84                 newblock->next = p->next;
  85                 newblock->prev = p;
  86                 p->next->prev = newblock;
  87                 p->next = newblock;
  88                 p->size -= newblock->size;
  89                 p = newblock;
  90         }
  91
  92         /* Maybe cut off the end of an existing block */
  93         if (size < p->size) {
  94                 struct mem_block *newblock = DRM_MALLOC(sizeof(*newblock));
  95                 if (!newblock)
  96                         goto out;
  97                 newblock->start = start + size;
  98                 newblock->size = p->size - size;
  99                 newblock->filp = NULL;
 100                 newblock->next = p->next;
 101                 newblock->prev = p;
 102                 p->next->prev = newblock;
 103                 p->next = newblock;
 104                 p->size = size;
 105         }
 106
 107       out:
 108         /* Our block is in the middle */
 109         p->filp = filp;
 110         return p;
 111 }
 112
 113 static struct mem_block *alloc_block(struct mem_block *heap, int size,
 114                                      int align2, DRMFILE filp)
 115 {
 116         struct mem_block *p;
 117         int mask = (1 << align2) - 1;
 118
 119         for (p = heap->next; p != heap; p = p->next) {
 120                 int start = (p->start + mask) & ~mask;
 121                 if (p->filp == NULL && start + size <= p->start + p->size)
 122                         return split_block(p, start, size, filp);
 123         }
 124
 125         return NULL;
 126 }
 127
 128 static struct mem_block *find_block(struct mem_block *heap, int start)
 129 {
 130         struct mem_block *p;
 131
 132         for (p = heap->next; p != heap; p = p->next)
 133                 if (p->start == start)
 134                         return p;
 135
 136         return NULL;
 137 }
 138
 139 static void free_block(struct mem_block *p)
 140 {
 141         p->filp = NULL;
 142
 143         /* Assumes a single contiguous range.  Needs a special filp in
 144          * 'heap' to stop it being subsumed.
 145          */
 146         if (p->next->filp == NULL) {
 147                 struct mem_block *q = p->next;
 148                 p->size += q->size;
 149                 p->next = q->next;
 150                 p->next->prev = p;
 151                 DRM_FREE(q, sizeof(*q));
 152         }
 153
 154         if (p->prev->filp == NULL) {
 155                 struct mem_block *q = p->prev;
 156                 q->size += p->size;
 157                 q->next = p->next;
 158                 q->next->prev = q;
 159                 DRM_FREE(p, sizeof(*q));
 160         }
 161 }
 162
 163 /* Initialize.  How to check for an uninitialized heap?
 164  */
 165 static int init_heap(struct mem_block **heap, int start, int size)
 166 {
 167         struct mem_block *blocks = DRM_MALLOC(sizeof(*blocks));
 168
 169         if (!blocks)
 170                 return -ENOMEM;
 171
 172         *heap = DRM_MALLOC(sizeof(**heap));
 173         if (!*heap) {
 174                 DRM_FREE(blocks, sizeof(*blocks));
 175                 return -ENOMEM;
 176         }
 177
 178         blocks->start = start;
 179         blocks->size = size;
 180         blocks->filp = NULL;
 181         blocks->next = blocks->prev = *heap;
 182
 183         memset(*heap, 0, sizeof(**heap));
 184         (*heap)->filp = (DRMFILE) - 1;
 185         (*heap)->next = (*heap)->prev = blocks;
 186         return 0;
 187 }
 188
 189 /* Free all blocks associated with the releasing file.
 190  */
 191 void i915_mem_release(drm_device_t * dev, DRMFILE filp, struct mem_block *heap)
 192 {
 193         struct mem_block *p;
 194
 195         if (!heap || !heap->next)
 196                 return;
 197
 198         for (p = heap->next; p != heap; p = p->next) {
 199                 if (p->filp == filp) {
 200                         p->filp = NULL;
 201                         mark_block(dev, p, 0);
 202                 }
 203         }
 204
 205         /* Assumes a single contiguous range.  Needs a special filp in
 206          * 'heap' to stop it being subsumed.
 207          */
 208         for (p = heap->next; p != heap; p = p->next) {
 209                 while (p->filp == NULL && p->next->filp == NULL) {
 210                         struct mem_block *q = p->next;
 211                         p->size += q->size;
 212                         p->next = q->next;
 213                         p->next->prev = p;
 214                         DRM_FREE(q, sizeof(*q));
 215                 }
 216         }
 217 }
 218
 219 /* Shutdown.
 220  */
 221 void i915_mem_takedown(struct mem_block **heap)
 222 {
 223         struct mem_block *p;
 224
 225         if (!*heap)
 226                 return;
 227
 228         for (p = (*heap)->next; p != *heap;) {
 229                 struct mem_block *q = p;
 230                 p = p->next;
 231                 DRM_FREE(q, sizeof(*q));
 232         }
 233
 234         DRM_FREE(*heap, sizeof(**heap));
 235         *heap = NULL;
 236 }
 237
 238 static struct mem_block **get_heap(drm_i915_private_t * dev_priv, int region)
 239 {
 240         switch (region) {
 241         case I915_MEM_REGION_AGP:
 242                 return &dev_priv->agp_heap;
 243         default:
 244                 return NULL;
 245         }
 246 }
 247
 248 /* IOCTL HANDLERS */
 249
 250 int i915_mem_alloc(DRM_IOCTL_ARGS)
 251 {
 252         DRM_DEVICE;
 253         drm_i915_private_t *dev_priv = dev->dev_private;
 254         drm_i915_mem_alloc_t alloc;
 255         struct mem_block *block, **heap;
 256
 257         if (!dev_priv) {
 258                 DRM_ERROR("%s called with no initialization\n", __FUNCTION__);
 259                 return DRM_ERR(EINVAL);
 260         }
 261
 262         DRM_COPY_FROM_USER_IOCTL(alloc, (drm_i915_mem_alloc_t __user *) data,
 263                                  sizeof(alloc));
 264
 265         heap = get_heap(dev_priv, alloc.region);
 266         if (!heap || !*heap)
 267                 return DRM_ERR(EFAULT);
 268
 269         /* Make things easier on ourselves: all allocations at least
 270          * 4k aligned.
 271          */
 272         if (alloc.alignment < 12)
 273                 alloc.alignment = 12;
 274
 275         block = alloc_block(*heap, alloc.size, alloc.alignment, filp);
 276
 277         if (!block)
 278                 return DRM_ERR(ENOMEM);
 279
 280         mark_block(dev, block, 1);
 281
 282         if (DRM_COPY_TO_USER(alloc.region_offset, &block->start, sizeof(int))) {
 283                 DRM_ERROR("copy_to_user\n");
 284                 return DRM_ERR(EFAULT);
 285         }
 286
 287         return 0;
 288 }
 289
 290 int i915_mem_free(DRM_IOCTL_ARGS)
 291 {
 292         DRM_DEVICE;
 293         drm_i915_private_t *dev_priv = dev->dev_private;
 294         drm_i915_mem_free_t memfree;
 295         struct mem_block *block, **heap;
 296
 297         if (!dev_priv) {
 298                 DRM_ERROR("%s called with no initialization\n", __FUNCTION__);
 299                 return DRM_ERR(EINVAL);
 300         }
 301
 302         DRM_COPY_FROM_USER_IOCTL(memfree, (drm_i915_mem_free_t __user *) data,
 303                                  sizeof(memfree));
 304
 305         heap = get_heap(dev_priv, memfree.region);
 306         if (!heap || !*heap)
 307                 return DRM_ERR(EFAULT);
 308
 309         block = find_block(*heap, memfree.region_offset);
 310         if (!block)
 311                 return DRM_ERR(EFAULT);
 312
 313         if (block->filp != filp)
 314                 return DRM_ERR(EPERM);
 315
 316         mark_block(dev, block, 0);
 317         free_block(block);
 318         return 0;
 319 }
 320
 321 int i915_mem_init_heap(DRM_IOCTL_ARGS)
 322 {
 323         DRM_DEVICE;
 324         drm_i915_private_t *dev_priv = dev->dev_private;
 325         drm_i915_mem_init_heap_t initheap;
 326         struct mem_block **heap;
 327
 328         if (!dev_priv) {
 329                 DRM_ERROR("%s called with no initialization\n", __FUNCTION__);
 330                 return DRM_ERR(EINVAL);
 331         }
 332
 333         DRM_COPY_FROM_USER_IOCTL(initheap,
 334                                  (drm_i915_mem_init_heap_t __user *) data,
 335                                  sizeof(initheap));
 336
 337         heap = get_heap(dev_priv, initheap.region);
 338         if (!heap)
 339                 return DRM_ERR(EFAULT);
 340
 341         if (*heap) {
 342                 DRM_ERROR("heap already initialized?");
 343                 return DRM_ERR(EFAULT);
 344         }
 345
 346         return init_heap(heap, initheap.start, initheap.size);
 347 }