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i915_mem.c

/* i915_mem.c -- Simple agp/fb memory manager for i915 -*- linux-c -*-
 */
/*
 * Copyright 2003 Tungsten Graphics, Inc., Cedar Park, Texas.
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
 * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

#include "drmP.h"
#include "drm.h"
#include "i915_drm.h"
#include "i915_drv.h"

/* This memory manager is integrated into the global/local lru
 * mechanisms used by the clients.  Specifically, it operates by
 * setting the 'in_use' fields of the global LRU to indicate whether
 * this region is privately allocated to a client.
 *
 * This does require the client to actually respect that field.
 *
 * Currently no effort is made to allocate 'private' memory in any
 * clever way - the LRU information isn't used to determine which
 * block to allocate, and the ring is drained prior to allocations --
 * in other words allocation is expensive.
 */
static void mark_block(struct drm_device * dev, struct mem_block *p, int in_use)
{
      drm_i915_private_t *dev_priv = dev->dev_private;
      drm_i915_sarea_t *sarea_priv = dev_priv->sarea_priv;
      struct drm_tex_region *list;
      unsigned shift, nr;
      unsigned start;
      unsigned end;
      unsigned i;
      int age;

      shift = dev_priv->tex_lru_log_granularity;
      nr = I915_NR_TEX_REGIONS;

      start = p->start >> shift;
      end = (p->start + p->size - 1) >> shift;

      age = ++sarea_priv->texAge;
      list = sarea_priv->texList;

      /* Mark the regions with the new flag and update their age.  Move
       * them to head of list to preserve LRU semantics.
       */
      for (i = start; i <= end; i++) {
            list[i].in_use = in_use;
            list[i].age = age;

            /* remove_from_list(i)
             */
            list[(unsigned)list[i].next].prev = list[i].prev;
            list[(unsigned)list[i].prev].next = list[i].next;

            /* insert_at_head(list, i)
             */
            list[i].prev = nr;
            list[i].next = list[nr].next;
            list[(unsigned)list[nr].next].prev = i;
            list[nr].next = i;
      }
}

/* Very simple allocator for agp memory, working on a static range
 * already mapped into each client's address space.
 */

static struct mem_block *split_block(struct mem_block *p, int start, int size,
                             struct drm_file *file_priv)
{
      /* Maybe cut off the start of an existing block */
      if (start > p->start) {
            struct mem_block *newblock =
                drm_alloc(sizeof(*newblock), DRM_MEM_BUFLISTS);
            if (!newblock)
                  goto out;
            newblock->start = start;
            newblock->size = p->size - (start - p->start);
            newblock->file_priv = NULL;
            newblock->next = p->next;
            newblock->prev = p;
            p->next->prev = newblock;
            p->next = newblock;
            p->size -= newblock->size;
            p = newblock;
      }

      /* Maybe cut off the end of an existing block */
      if (size < p->size) {
            struct mem_block *newblock =
                drm_alloc(sizeof(*newblock), DRM_MEM_BUFLISTS);
            if (!newblock)
                  goto out;
            newblock->start = start + size;
            newblock->size = p->size - size;
            newblock->file_priv = NULL;
            newblock->next = p->next;
            newblock->prev = p;
            p->next->prev = newblock;
            p->next = newblock;
            p->size = size;
      }

      out:
      /* Our block is in the middle */
      p->file_priv = file_priv;
      return p;
}

static struct mem_block *alloc_block(struct mem_block *heap, int size,
                             int align2, struct drm_file *file_priv)
{
      struct mem_block *p;
      int mask = (1 << align2) - 1;

      for (p = heap->next; p != heap; p = p->next) {
            int start = (p->start + mask) & ~mask;
            if (p->file_priv == NULL && start + size <= p->start + p->size)
                  return split_block(p, start, size, file_priv);
      }

      return NULL;
}

static struct mem_block *find_block(struct mem_block *heap, int start)
{
      struct mem_block *p;

      for (p = heap->next; p != heap; p = p->next)
            if (p->start == start)
                  return p;

      return NULL;
}

static void free_block(struct mem_block *p)
{
      p->file_priv = NULL;

      /* Assumes a single contiguous range.  Needs a special file_priv in
       * 'heap' to stop it being subsumed.
       */
      if (p->next->file_priv == NULL) {
            struct mem_block *q = p->next;
            p->size += q->size;
            p->next = q->next;
            p->next->prev = p;
            drm_free(q, sizeof(*q), DRM_MEM_BUFLISTS);
      }

      if (p->prev->file_priv == NULL) {
            struct mem_block *q = p->prev;
            q->size += p->size;
            q->next = p->next;
            q->next->prev = q;
            drm_free(p, sizeof(*q), DRM_MEM_BUFLISTS);
      }
}

/* Initialize.  How to check for an uninitialized heap?
 */
static int init_heap(struct mem_block **heap, int start, int size)
{
      struct mem_block *blocks = drm_alloc(sizeof(*blocks), DRM_MEM_BUFLISTS);

      if (!blocks)
            return -ENOMEM;

      *heap = drm_alloc(sizeof(**heap), DRM_MEM_BUFLISTS);
      if (!*heap) {
            drm_free(blocks, sizeof(*blocks), DRM_MEM_BUFLISTS);
            return -ENOMEM;
      }

      blocks->start = start;
      blocks->size = size;
      blocks->file_priv = NULL;
      blocks->next = blocks->prev = *heap;

      memset(*heap, 0, sizeof(**heap));
      (*heap)->file_priv = (struct drm_file *) - 1;
      (*heap)->next = (*heap)->prev = blocks;
      return 0;
}

/* Free all blocks associated with the releasing file.
 */
void i915_mem_release(struct drm_device * dev, struct drm_file *file_priv,
                  struct mem_block *heap)
{
      struct mem_block *p;

      if (!heap || !heap->next)
            return;

      for (p = heap->next; p != heap; p = p->next) {
            if (p->file_priv == file_priv) {
                  p->file_priv = NULL;
                  mark_block(dev, p, 0);
            }
      }

      /* Assumes a single contiguous range.  Needs a special file_priv in
       * 'heap' to stop it being subsumed.
       */
      for (p = heap->next; p != heap; p = p->next) {
            while (p->file_priv == NULL && p->next->file_priv == NULL) {
                  struct mem_block *q = p->next;
                  p->size += q->size;
                  p->next = q->next;
                  p->next->prev = p;
                  drm_free(q, sizeof(*q), DRM_MEM_BUFLISTS);
            }
      }
}

/* Shutdown.
 */
void i915_mem_takedown(struct mem_block **heap)
{
      struct mem_block *p;

      if (!*heap)
            return;

      for (p = (*heap)->next; p != *heap;) {
            struct mem_block *q = p;
            p = p->next;
            drm_free(q, sizeof(*q), DRM_MEM_BUFLISTS);
      }

      drm_free(*heap, sizeof(**heap), DRM_MEM_BUFLISTS);
      *heap = NULL;
}

static struct mem_block **get_heap(drm_i915_private_t * dev_priv, int region)
{
      switch (region) {
      case I915_MEM_REGION_AGP:
            return &dev_priv->agp_heap;
      default:
            return NULL;
      }
}

/* IOCTL HANDLERS */

int i915_mem_alloc(struct drm_device *dev, void *data,
               struct drm_file *file_priv)
{
      drm_i915_private_t *dev_priv = dev->dev_private;
      drm_i915_mem_alloc_t *alloc = data;
      struct mem_block *block, **heap;

      if (!dev_priv) {
            DRM_ERROR("%s called with no initialization\n", __FUNCTION__);
            return -EINVAL;
      }

      heap = get_heap(dev_priv, alloc->region);
      if (!heap || !*heap)
            return -EFAULT;

      /* Make things easier on ourselves: all allocations at least
       * 4k aligned.
       */
      if (alloc->alignment < 12)
            alloc->alignment = 12;

      block = alloc_block(*heap, alloc->size, alloc->alignment, file_priv);

      if (!block)
            return -ENOMEM;

      mark_block(dev, block, 1);

      if (DRM_COPY_TO_USER(alloc->region_offset, &block->start,
                       sizeof(int))) {
            DRM_ERROR("copy_to_user\n");
            return -EFAULT;
      }

      return 0;
}

int i915_mem_free(struct drm_device *dev, void *data,
              struct drm_file *file_priv)
{
      drm_i915_private_t *dev_priv = dev->dev_private;
      drm_i915_mem_free_t *memfree = data;
      struct mem_block *block, **heap;

      if (!dev_priv) {
            DRM_ERROR("%s called with no initialization\n", __FUNCTION__);
            return -EINVAL;
      }

      heap = get_heap(dev_priv, memfree->region);
      if (!heap || !*heap)
            return -EFAULT;

      block = find_block(*heap, memfree->region_offset);
      if (!block)
            return -EFAULT;

      if (block->file_priv != file_priv)
            return -EPERM;

      mark_block(dev, block, 0);
      free_block(block);
      return 0;
}

int i915_mem_init_heap(struct drm_device *dev, void *data,
                   struct drm_file *file_priv)
{
      drm_i915_private_t *dev_priv = dev->dev_private;
      drm_i915_mem_init_heap_t *initheap = data;
      struct mem_block **heap;

      if (!dev_priv) {
            DRM_ERROR("%s called with no initialization\n", __FUNCTION__);
            return -EINVAL;
      }

      heap = get_heap(dev_priv, initheap->region);
      if (!heap)
            return -EFAULT;

      if (*heap) {
            DRM_ERROR("heap already initialized?");
            return -EFAULT;
      }

      return init_heap(heap, initheap->start, initheap->size);
}

int i915_mem_destroy_heap( struct drm_device *dev, void *data,
                     struct drm_file *file_priv )
{
      drm_i915_private_t *dev_priv = dev->dev_private;
      drm_i915_mem_destroy_heap_t *destroyheap = data;
      struct mem_block **heap;

      if ( !dev_priv ) {
            DRM_ERROR( "%s called with no initialization\n", __FUNCTION__ );
            return -EINVAL;
      }

      heap = get_heap( dev_priv, destroyheap->region );
      if (!heap) {
            DRM_ERROR("get_heap failed");
            return -EFAULT;
      }
      
      if (!*heap) {
            DRM_ERROR("heap not initialized?");
            return -EFAULT;
      }

      i915_mem_takedown( heap );
      return 0;
}


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