/* radeon_mem.c -- Simple agp/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 "radeon.h"
#include "drmP.h"
#include "drm.h"
#include "radeon_drm.h"
#include "radeon_drv.h"
#include "drm_os_linux.h"

/* 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,
				     int pid )
{
	/* 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->pid = 0;
		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->pid = 0;
		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->pid = pid;
	return p;
}

static struct mem_block *alloc_block( struct mem_block *heap, int size, 
				      int align2, int pid )
{
	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->pid == 0 && start + size <= p->start + p->size)
			return split_block( p, start, size, pid );
	}

	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->pid = 0;

	/* Assumes a single contiguous range.  Needs a special pid in
	 * 'heap' to stop it being subsumed.
	 */
	if (p->next->pid == 0) {
		struct mem_block *q = p->next;
		p->size += q->size;
		p->next = q->next;
		p->next->prev = p;
		kfree(q);
	}

	if (p->prev->pid == 0) {
		struct mem_block *q = p->prev;
		q->size += p->size;
		q->next = p->next;
		q->next->prev = q;
		kfree(p);
	}
}

#if 0
static void print_heap( struct mem_block *heap )
{
	struct mem_block *p;

	for (p = heap->next ; p != heap ; p = p->next) 
		DRM_DEBUG("0x%x..0x%x (0x%x) -- owner %d\n",
			  p->start, p->start + p->size,
			  p->size, p->pid);
}
#endif

/* 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->pid = 0;
	blocks->next = blocks->prev = *heap;

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


/* Free all blocks associated with the releasing pid.
 */
void radeon_mem_release( struct mem_block *heap )
{
	int pid = current->pid;
	struct mem_block *p;

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

	for (p = heap->next ; p != heap ; p = p->next) {
		if (p->pid == pid) 
			p->pid = 0;
	}

	/* Assumes a single contiguous range.  Needs a special pid in
	 * 'heap' to stop it being subsumed.
	 */
	for (p = heap->next ; p != heap ; p = p->next) {
		while (p->pid == 0 && p->next->pid == 0) {
			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 = 0;
}



/* IOCTL HANDLERS */

static struct mem_block **get_heap( drm_radeon_private_t *dev_priv,
				   int region )
{
	switch( region ) {
	case RADEON_MEM_REGION_AGP:
 		return &dev_priv->agp_heap; 
	case RADEON_MEM_REGION_FB:
		return &dev_priv->fb_heap;
	default:
		return 0;
	}
}

int radeon_mem_alloc(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long data )
{
        drm_file_t      *priv   = filp->private_data;
        drm_device_t    *dev    = priv->dev;
        drm_radeon_private_t *dev_priv = dev->dev_private;
	drm_radeon_mem_alloc_t alloc;
	struct mem_block *block, **heap;

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

	DRM_COPY_FROM_USER_IOCTL( alloc, (drm_radeon_mem_alloc_t *)data,
				  sizeof(alloc) );

	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,
			     current->pid );

	if (!block) 
		return -ENOMEM;

	if ( 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 inode *inode, struct file *filp, unsigned int cmd, unsigned long data)
{
        drm_file_t      *priv   = filp->private_data;
        drm_device_t    *dev    = priv->dev;
	drm_radeon_private_t *dev_priv = dev->dev_private;
	drm_radeon_mem_free_t memfree;
	struct mem_block *block, **heap;

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

	DRM_COPY_FROM_USER_IOCTL( memfree, (drm_radeon_mem_free_t *)data,
				  sizeof(memfree) );

	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->pid != current->pid)
		return -EPERM;

	free_block( block );	
	return 0;
}

int radeon_mem_init_heap(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long data)
{
        drm_file_t      *priv   = filp->private_data;
        drm_device_t    *dev    = priv->dev;
	drm_radeon_private_t *dev_priv = dev->dev_private;
	drm_radeon_mem_init_heap_t initheap;
	struct mem_block **heap;

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

	DRM_COPY_FROM_USER_IOCTL( initheap, (drm_radeon_mem_init_heap_t *)data,
				  sizeof(initheap) );

	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 );
}