/* 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 <keith@tungstengraphics.com>
 */

#include "drmP.h"
#include "drm.h"
#include "radeon_drm.h"
#include "radeon_drv.h"

/* Very simple allocator for GART 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 = kmalloc(sizeof(*newblock),
						     GFP_KERNEL);
		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 = kmalloc(sizeof(*newblock),
						     GFP_KERNEL);
		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;

	list_for_each(p, heap) {
		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;

	list_for_each(p, heap)
	    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;
		kfree(q);
	}

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

/* 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), GFP_KERNEL);

	if (!blocks)
		return -ENOMEM;

	*heap = kmalloc(sizeof(**heap), GFP_KERNEL);
	if (!*heap) {
		kfree(blocks);
		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 radeon_mem_release(struct drm_file *file_priv, struct mem_block *heap)
{
	struct mem_block *p;

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

	list_for_each(p, heap) {
		if (p->file_priv == file_priv)
			p->file_priv = NULL;
	}

	/* Assumes a single contiguous range.  Needs a special file_priv in
	 * 'heap' to stop it being subsumed.
	 */
	list_for_each(p, heap) {
		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;
			kfree(q);
		}
	}
}

/* Shutdown.
 */
void radeon_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;
		kfree(q);
	}

	kfree(*heap);
	*heap = NULL;
}

/* IOCTL HANDLERS */

static struct mem_block **get_heap(drm_radeon_private_t * dev_priv, int region)
{
	switch (region) {
	case RADEON_MEM_REGION_GART:
		return &dev_priv->gart_heap;
	case RADEON_MEM_REGION_FB:
		return &dev_priv->fb_heap;
	default:
		return NULL;
	}
}

int radeon_mem_alloc(struct drm_device *dev, void *data, struct drm_file *file_priv)
{
	drm_radeon_private_t *dev_priv = dev->dev_private;
	drm_radeon_mem_alloc_t *alloc = data;
	struct mem_block *block, **heap;

	if (!dev_priv) {
		DRM_ERROR("called with no initialization\n");
		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;

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

	return 0;
}

int radeon_mem_free(struct drm_device *dev, void *data, struct drm_file *file_priv)
{
	drm_radeon_private_t *dev_priv = dev->dev_private;
	drm_radeon_mem_free_t *memfree = data;
	struct mem_block *block, **heap;

	if (!dev_priv) {
		DRM_ERROR("called with no initialization\n");
		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;

	free_block(block);
	return 0;
}

int radeon_mem_init_heap(struct drm_device *dev, void *data, struct drm_file *file_priv)
{
	drm_radeon_private_t *dev_priv = dev->dev_private;
	drm_radeon_mem_init_heap_t *initheap = data;
	struct mem_block **heap;

	if (!dev_priv) {
		DRM_ERROR("called with no initialization\n");
		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);
}