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/* radeon_mem.c -- Simple GART/fb memory manager for radeon -*- linux-c -*- */

/*

 * Copyright (C) The Weather Channel, Inc.  2002.  All Rights Reserved.

 *

 * The Weather Channel (TM) funded Tungsten Graphics to develop the

 * initial release of the Radeon 8500 driver under the XFree86 license.

 * This notice must be preserved.

 *

 * 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, sublicense,

 * 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 NONINFRINGEMENT.  IN NO EVENT SHALL

 * PRECISION INSIGHT 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.

 *

 * Authors:

 *    Keith Whitwell 

 */

#define USED_BLOCK  1

#define list_for_each(entry, head)        \

   for (entry = (head)->next; entry != head; entry = (entry)->next)

/* Very simple allocator for GART memory, working on a static range

 * already mapped into each client's address space.

 */

struct mem_block {

	struct mem_block *next;

	struct mem_block *prev;

	int start;

	int size;

};

/* Initialize.  How to check for an uninitialized heap?

 */

static int init_heap(struct mem_block **heap, int start, int size)

{

  struct mem_block *blocks = kmalloc(sizeof(*blocks));

	if (!blocks)

    return -1; //-ENOMEM;

  *heap = kmalloc(sizeof(**heap));

  if (!*heap)

  {

    kfree(blocks);

    return -1; //-ENOMEM;

	}

  blocks->start = start;

  blocks->size  = size;

  blocks->next  = blocks->prev = *heap;

  __clear(*heap,sizeof(**heap));

	(*heap)->next = (*heap)->prev = blocks;

	return 0;

}

static struct mem_block **get_heap(RHDPtr rhdPtr, int region)

{

  switch (region)

  {

    case RHD_MEM_GART:

      return &rhdPtr->gart_heap;

    case RHD_MEM_FB:

      return &rhdPtr->fb_heap;

    default:

      return NULL;

	}

}

static struct mem_block *split_block(struct mem_block *p, int size)

{

	/* Maybe cut off the end of an existing block */

    if (size < p->size)

    {

      struct mem_block *newblock = kmalloc(sizeof(*newblock));

      if (!newblock)

        goto out;

      newblock->start = p->start + size;

      newblock->size = p->size - size;

      newblock->next = p->next;

      newblock->prev = p;

      p->next->prev = newblock;

      p->next = newblock;

      p->size = size;

      p->start|=1;

    }

out:

    return p;

}

static struct mem_block *alloc_block(struct mem_block *heap, int size)

{

	struct mem_block *p;

  list_for_each(p, heap)

  {

    if ( !(p->start & USED_BLOCK) && size <= p->size)

      return split_block(p, size);

	}

	return NULL;

}

static struct mem_block *find_block(struct mem_block *heap, int start)

{

	struct mem_block *p;

	list_for_each(p, heap)

    if ((p->start & ~USED_BLOCK) == start)

			return p;

	return NULL;

}

static void free_block(struct mem_block *p)

{

	/* Assumes a single contiguous range.  Needs a special file_priv in

	 * 'heap' to stop it being subsumed.

	 */

  p->start &= ~USED_BLOCK;

  if ( !(p->next->start & USED_BLOCK))

  {

		struct mem_block *q = p->next;

		p->size += q->size;

		p->next = q->next;

		p->next->prev = p;

    kfree(q);

	}

  if ( !(p->prev->start & USED_BLOCK))

  {

		struct mem_block *q = p->prev;

		q->size += p->size;

		q->next = p->next;

		q->next->prev = q;

    kfree(p);

	}

}

int rhdInitHeap(RHDPtr rhdPtr)

{

  int base = rhdPtr->FbFreeStart;

  return init_heap(&rhdPtr->fb_heap, base, rhdPtr->FbFreeSize);

};

void *rhd_mem_alloc(RHDPtr rhdPtr,int region, int size)

{

	struct mem_block *block, **heap;

  heap = get_heap(rhdPtr, region);

	if (!heap || !*heap)

    return NULL;

	/* Make things easier on ourselves: all allocations at least

	 * 4k aligned.

	 */

  size = (size+4095) & ~4095;

  block = alloc_block(*heap, size);

	if (!block)

    return NULL;

  return (void*)(block->start & ~USED_BLOCK);

}

int rhd_mem_free(RHDPtr rhdPtr, int region, void *offset)

{

	struct mem_block *block, **heap;

  heap = get_heap(rhdPtr, region);

	if (!heap || !*heap)

    return -1;

  block = find_block(*heap, (int)offset);

	if (!block)

    return -1;

  if ( !(block->start & 1))

    return -1;

	free_block(block);

	return 0;

}