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/**************************************************************************

 *

 * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., USA.

 * 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

 * THE COPYRIGHT HOLDERS, AUTHORS 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.

 *

 *

 **************************************************************************/

/*

 * Generic simple memory manager implementation. Intended to be used as a base

 * class implementation for more advanced memory managers.

 *

 * Note that the algorithm used is quite simple and there might be substantial

 * performance gains if a smarter free list is implemented. Currently it is just an

 * unordered stack of free regions. This could easily be improved if an RB-tree

 * is used instead. At least if we expect heavy fragmentation.

 *

 * Aligned allocations can also see improvement.

 *

 * Authors:

 * Thomas Hellström 

 */

#include 

#include 

#include 

#include 

#include 

#define MM_UNUSED_TARGET 4

static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,

						unsigned long size,

						unsigned alignment,

						unsigned long color,

						enum drm_mm_search_flags flags);

static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm,

						unsigned long size,

						unsigned alignment,

						unsigned long color,

						unsigned long start,

						unsigned long end,

						enum drm_mm_search_flags flags);

static void drm_mm_insert_helper(struct drm_mm_node *hole_node,

				 struct drm_mm_node *node,

				 unsigned long size, unsigned alignment,

				 unsigned long color)

{

	struct drm_mm *mm = hole_node->mm;

	unsigned long hole_start = drm_mm_hole_node_start(hole_node);

	unsigned long hole_end = drm_mm_hole_node_end(hole_node);

	unsigned long adj_start = hole_start;

	unsigned long adj_end = hole_end;

	BUG_ON(node->allocated);

	if (mm->color_adjust)

		mm->color_adjust(hole_node, color, &adj_start, &adj_end);

	if (alignment) {

		unsigned tmp = adj_start % alignment;

		if (tmp)

			adj_start += alignment - tmp;

	}

	if (adj_start == hole_start) {

		hole_node->hole_follows = 0;

		list_del(&hole_node->hole_stack);

	}

	node->start = adj_start;

	node->size = size;

	node->mm = mm;

	node->color = color;

	node->allocated = 1;

	INIT_LIST_HEAD(&node->hole_stack);

	list_add(&node->node_list, &hole_node->node_list);

	BUG_ON(node->start + node->size > adj_end);

	node->hole_follows = 0;

	if (__drm_mm_hole_node_start(node) < hole_end) {

		list_add(&node->hole_stack, &mm->hole_stack);

		node->hole_follows = 1;

	}

}

int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node)

{

	struct drm_mm_node *hole;

	unsigned long end = node->start + node->size;

	unsigned long hole_start;

	unsigned long hole_end;

	BUG_ON(node == NULL);

	/* Find the relevant hole to add our node to */

	drm_mm_for_each_hole(hole, mm, hole_start, hole_end) {

		if (hole_start > node->start || hole_end < end)

			continue;

		node->mm = mm;

		node->allocated = 1;

		INIT_LIST_HEAD(&node->hole_stack);

		list_add(&node->node_list, &hole->node_list);

		if (node->start == hole_start) {

			hole->hole_follows = 0;

			list_del_init(&hole->hole_stack);

		}

		node->hole_follows = 0;

		if (end != hole_end) {

			list_add(&node->hole_stack, &mm->hole_stack);

			node->hole_follows = 1;

		}

		return 0;

	}

	WARN(1, "no hole found for node 0x%lx + 0x%lx\n",

	     node->start, node->size);

	return -ENOSPC;

}

EXPORT_SYMBOL(drm_mm_reserve_node);

/**

 * Search for free space and insert a preallocated memory node. Returns

 * -ENOSPC if no suitable free area is available. The preallocated memory node

 * must be cleared.

 */

int drm_mm_insert_node_generic(struct drm_mm *mm, struct drm_mm_node *node,

			       unsigned long size, unsigned alignment,

			       unsigned long color,

			       enum drm_mm_search_flags flags)

{

	struct drm_mm_node *hole_node;

	hole_node = drm_mm_search_free_generic(mm, size, alignment,

					       color, flags);

	if (!hole_node)

		return -ENOSPC;

	drm_mm_insert_helper(hole_node, node, size, alignment, color);

	return 0;

}

EXPORT_SYMBOL(drm_mm_insert_node_generic);

static void drm_mm_insert_helper_range(struct drm_mm_node *hole_node,

				       struct drm_mm_node *node,

				       unsigned long size, unsigned alignment,

				       unsigned long color,

				       unsigned long start, unsigned long end)

{

	struct drm_mm *mm = hole_node->mm;

	unsigned long hole_start = drm_mm_hole_node_start(hole_node);

	unsigned long hole_end = drm_mm_hole_node_end(hole_node);

	unsigned long adj_start = hole_start;

	unsigned long adj_end = hole_end;

	BUG_ON(!hole_node->hole_follows || node->allocated);

	if (adj_start < start)

		adj_start = start;

	if (adj_end > end)

		adj_end = end;

	if (mm->color_adjust)

		mm->color_adjust(hole_node, color, &adj_start, &adj_end);

	if (alignment) {

		unsigned tmp = adj_start % alignment;

	if (tmp)

			adj_start += alignment - tmp;

	}

	if (adj_start == hole_start) {

		hole_node->hole_follows = 0;

		list_del(&hole_node->hole_stack);

	}

	node->start = adj_start;

	node->size = size;

	node->mm = mm;

	node->color = color;

	node->allocated = 1;

	INIT_LIST_HEAD(&node->hole_stack);

	list_add(&node->node_list, &hole_node->node_list);

	BUG_ON(node->start + node->size > adj_end);

	BUG_ON(node->start + node->size > end);

	node->hole_follows = 0;

	if (__drm_mm_hole_node_start(node) < hole_end) {

		list_add(&node->hole_stack, &mm->hole_stack);

		node->hole_follows = 1;

	}

}

/**

 * Search for free space and insert a preallocated memory node. Returns

 * -ENOSPC if no suitable free area is available. This is for range

 * restricted allocations. The preallocated memory node must be cleared.

 */

int drm_mm_insert_node_in_range_generic(struct drm_mm *mm, struct drm_mm_node *node,

					unsigned long size, unsigned alignment, unsigned long color,

					unsigned long start, unsigned long end,

					enum drm_mm_search_flags flags)

{

	struct drm_mm_node *hole_node;

	hole_node = drm_mm_search_free_in_range_generic(mm,

							size, alignment, color,

							start, end, flags);

	if (!hole_node)

		return -ENOSPC;

	drm_mm_insert_helper_range(hole_node, node,

				   size, alignment, color,

				   start, end);

	return 0;

}

EXPORT_SYMBOL(drm_mm_insert_node_in_range_generic);

/**

 * Remove a memory node from the allocator.

 */

void drm_mm_remove_node(struct drm_mm_node *node)

{

	struct drm_mm *mm = node->mm;

	struct drm_mm_node *prev_node;

	if (WARN_ON(!node->allocated))

		return;

	BUG_ON(node->scanned_block || node->scanned_prev_free

				   || node->scanned_next_free);

	prev_node =

	    list_entry(node->node_list.prev, struct drm_mm_node, node_list);

	if (node->hole_follows) {

		BUG_ON(__drm_mm_hole_node_start(node) ==

		       __drm_mm_hole_node_end(node));

		list_del(&node->hole_stack);

	} else

		BUG_ON(__drm_mm_hole_node_start(node) !=

		       __drm_mm_hole_node_end(node));

	if (!prev_node->hole_follows) {

		prev_node->hole_follows = 1;

		list_add(&prev_node->hole_stack, &mm->hole_stack);

				} else

		list_move(&prev_node->hole_stack, &mm->hole_stack);

	list_del(&node->node_list);

	node->allocated = 0;

}

EXPORT_SYMBOL(drm_mm_remove_node);

static int check_free_hole(unsigned long start, unsigned long end,

			   unsigned long size, unsigned alignment)

{

	if (end - start < size)

		return 0;

	if (alignment) {

		unsigned tmp = start % alignment;

		if (tmp)

			start += alignment - tmp;

	}

	return end >= start + size;

}

static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,

				       unsigned long size,

					       unsigned alignment,

					       unsigned long color,

						      enum drm_mm_search_flags flags)

{

	struct drm_mm_node *entry;

	struct drm_mm_node *best;

	unsigned long adj_start;

	unsigned long adj_end;

	unsigned long best_size;

	BUG_ON(mm->scanned_blocks);

	best = NULL;

	best_size = ~0UL;

	drm_mm_for_each_hole(entry, mm, adj_start, adj_end) {

		if (mm->color_adjust) {

			mm->color_adjust(entry, color, &adj_start, &adj_end);

			if (adj_end <= adj_start)

				continue;

		}

		if (!check_free_hole(adj_start, adj_end, size, alignment))

			continue;

		if (!(flags & DRM_MM_SEARCH_BEST))

				return entry;

			if (entry->size < best_size) {

				best = entry;

				best_size = entry->size;

			}

		}

	return best;

}

static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm,

						unsigned long size,

						unsigned alignment,

							unsigned long color,

						unsigned long start,

						unsigned long end,

							enum drm_mm_search_flags flags)

{

	struct drm_mm_node *entry;

	struct drm_mm_node *best;

	unsigned long adj_start;

	unsigned long adj_end;

	unsigned long best_size;

	BUG_ON(mm->scanned_blocks);

	best = NULL;

	best_size = ~0UL;

	drm_mm_for_each_hole(entry, mm, adj_start, adj_end) {

		if (adj_start < start)

			adj_start = start;

		if (adj_end > end)

			adj_end = end;

		if (mm->color_adjust) {

			mm->color_adjust(entry, color, &adj_start, &adj_end);

			if (adj_end <= adj_start)

				continue;

		}

		if (!check_free_hole(adj_start, adj_end, size, alignment))

			continue;

		if (!(flags & DRM_MM_SEARCH_BEST))

				return entry;

			if (entry->size < best_size) {

				best = entry;

				best_size = entry->size;

			}

		}

	return best;

}

/**

 * Moves an allocation. To be used with embedded struct drm_mm_node.

 */

void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new)

{

	list_replace(&old->node_list, &new->node_list);

	list_replace(&old->hole_stack, &new->hole_stack);

	new->hole_follows = old->hole_follows;

	new->mm = old->mm;

	new->start = old->start;

	new->size = old->size;

	new->color = old->color;

	old->allocated = 0;

	new->allocated = 1;

}

EXPORT_SYMBOL(drm_mm_replace_node);

/**

 * Initializa lru scanning.

 *

 * This simply sets up the scanning routines with the parameters for the desired

 * hole.

 *

 * Warning: As long as the scan list is non-empty, no other operations than

 * adding/removing nodes to/from the scan list are allowed.

 */

void drm_mm_init_scan(struct drm_mm *mm,

		      unsigned long size,

		      unsigned alignment,

		      unsigned long color)

{

	mm->scan_color = color;

	mm->scan_alignment = alignment;

	mm->scan_size = size;

	mm->scanned_blocks = 0;

	mm->scan_hit_start = 0;

	mm->scan_hit_end = 0;

	mm->scan_check_range = 0;

	mm->prev_scanned_node = NULL;

}

EXPORT_SYMBOL(drm_mm_init_scan);

/**

 * Initializa lru scanning.

 *

 * This simply sets up the scanning routines with the parameters for the desired

 * hole. This version is for range-restricted scans.

 *

 * Warning: As long as the scan list is non-empty, no other operations than

 * adding/removing nodes to/from the scan list are allowed.

 */

void drm_mm_init_scan_with_range(struct drm_mm *mm,

				 unsigned long size,

				 unsigned alignment,

				 unsigned long color,

				 unsigned long start,

				 unsigned long end)

{

	mm->scan_color = color;

	mm->scan_alignment = alignment;

	mm->scan_size = size;

	mm->scanned_blocks = 0;

	mm->scan_hit_start = 0;

	mm->scan_hit_end = 0;

	mm->scan_start = start;

	mm->scan_end = end;

	mm->scan_check_range = 1;

	mm->prev_scanned_node = NULL;

}

EXPORT_SYMBOL(drm_mm_init_scan_with_range);

/**

 * Add a node to the scan list that might be freed to make space for the desired

 * hole.

 *

 * Returns non-zero, if a hole has been found, zero otherwise.

 */

int drm_mm_scan_add_block(struct drm_mm_node *node)

{

	struct drm_mm *mm = node->mm;

	struct drm_mm_node *prev_node;

	unsigned long hole_start, hole_end;

	unsigned long adj_start, adj_end;

	mm->scanned_blocks++;

	BUG_ON(node->scanned_block);

	node->scanned_block = 1;

		prev_node = list_entry(node->node_list.prev, struct drm_mm_node,

				       node_list);

	node->scanned_preceeds_hole = prev_node->hole_follows;

	prev_node->hole_follows = 1;

	list_del(&node->node_list);

	node->node_list.prev = &prev_node->node_list;

	node->node_list.next = &mm->prev_scanned_node->node_list;

	mm->prev_scanned_node = node;

	adj_start = hole_start = drm_mm_hole_node_start(prev_node);

	adj_end = hole_end = drm_mm_hole_node_end(prev_node);

	if (mm->scan_check_range) {

		if (adj_start < mm->scan_start)

			adj_start = mm->scan_start;

		if (adj_end > mm->scan_end)

			adj_end = mm->scan_end;

	}

	if (mm->color_adjust)

		mm->color_adjust(prev_node, mm->scan_color,

				 &adj_start, &adj_end);

	if (check_free_hole(adj_start, adj_end,

			    mm->scan_size, mm->scan_alignment)) {

		mm->scan_hit_start = hole_start;

		mm->scan_hit_end = hole_end;

		return 1;

	}

	return 0;

}

EXPORT_SYMBOL(drm_mm_scan_add_block);

/**

 * Remove a node from the scan list.

 *

 * Nodes _must_ be removed in the exact same order from the scan list as they

 * have been added, otherwise the internal state of the memory manager will be

 * corrupted.

 *

 * When the scan list is empty, the selected memory nodes can be freed. An

 * immediately following drm_mm_search_free with !DRM_MM_SEARCH_BEST will then

 * return the just freed block (because its at the top of the free_stack list).

 *

 * Returns one if this block should be evicted, zero otherwise. Will always

 * return zero when no hole has been found.

 */

int drm_mm_scan_remove_block(struct drm_mm_node *node)

{

	struct drm_mm *mm = node->mm;

	struct drm_mm_node *prev_node;

	mm->scanned_blocks--;

	BUG_ON(!node->scanned_block);

	node->scanned_block = 0;

	prev_node = list_entry(node->node_list.prev, struct drm_mm_node,

			       node_list);

	prev_node->hole_follows = node->scanned_preceeds_hole;

	list_add(&node->node_list, &prev_node->node_list);

	 return (drm_mm_hole_node_end(node) > mm->scan_hit_start &&

		 node->start < mm->scan_hit_end);

}

EXPORT_SYMBOL(drm_mm_scan_remove_block);

int drm_mm_clean(struct drm_mm * mm)

{

	struct list_head *head = &mm->head_node.node_list;

	return (head->next->next == head);

}

EXPORT_SYMBOL(drm_mm_clean);

void drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size)

{

	INIT_LIST_HEAD(&mm->hole_stack);

	mm->scanned_blocks = 0;

	/* Clever trick to avoid a special case in the free hole tracking. */

	INIT_LIST_HEAD(&mm->head_node.node_list);

	INIT_LIST_HEAD(&mm->head_node.hole_stack);

	mm->head_node.hole_follows = 1;

	mm->head_node.scanned_block = 0;

	mm->head_node.scanned_prev_free = 0;

	mm->head_node.scanned_next_free = 0;

	mm->head_node.mm = mm;

	mm->head_node.start = start + size;

	mm->head_node.size = start - mm->head_node.start;

	list_add_tail(&mm->head_node.hole_stack, &mm->hole_stack);

	mm->color_adjust = NULL;

}

EXPORT_SYMBOL(drm_mm_init);

void drm_mm_takedown(struct drm_mm * mm)

{

	WARN(!list_empty(&mm->head_node.node_list),

	     "Memory manager not clean during takedown.\n");

}

EXPORT_SYMBOL(drm_mm_takedown);

static unsigned long drm_mm_debug_hole(struct drm_mm_node *entry,

				       const char *prefix)

{

	unsigned long hole_start, hole_end, hole_size;

	if (entry->hole_follows) {

		hole_start = drm_mm_hole_node_start(entry);

		hole_end = drm_mm_hole_node_end(entry);

	hole_size = hole_end - hole_start;

		printk(KERN_DEBUG "%s 0x%08lx-0x%08lx: %8lu: free\n",

			prefix, hole_start, hole_end,

			hole_size);

		return hole_size;

	}

	return 0;

}

void drm_mm_debug_table(struct drm_mm *mm, const char *prefix)

{

	struct drm_mm_node *entry;

	unsigned long total_used = 0, total_free = 0, total = 0;

	total_free += drm_mm_debug_hole(&mm->head_node, prefix);

	drm_mm_for_each_node(entry, mm) {

		printk(KERN_DEBUG "%s 0x%08lx-0x%08lx: %8lu: used\n",

			prefix, entry->start, entry->start + entry->size,

			entry->size);

		total_used += entry->size;

		total_free += drm_mm_debug_hole(entry, prefix);

		}

	total = total_free + total_used;

	printk(KERN_DEBUG "%s total: %lu, used %lu free %lu\n", prefix, total,

		total_used, total_free);

}

EXPORT_SYMBOL(drm_mm_debug_table);

#if defined(CONFIG_DEBUG_FS)

static unsigned long drm_mm_dump_hole(struct seq_file *m, struct drm_mm_node *entry)

{

	unsigned long hole_start, hole_end, hole_size;

	if (entry->hole_follows) {

		hole_start = drm_mm_hole_node_start(entry);

		hole_end = drm_mm_hole_node_end(entry);

	hole_size = hole_end - hole_start;

		seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: free\n",

				hole_start, hole_end, hole_size);

		return hole_size;

	}

	return 0;

}

int drm_mm_dump_table(struct seq_file *m, struct drm_mm *mm)

{

	struct drm_mm_node *entry;

	unsigned long total_used = 0, total_free = 0, total = 0;

	total_free += drm_mm_dump_hole(m, &mm->head_node);

	drm_mm_for_each_node(entry, mm) {

		seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: used\n",

				entry->start, entry->start + entry->size,

				entry->size);

		total_used += entry->size;

		total_free += drm_mm_dump_hole(m, entry);

		}

	total = total_free + total_used;

	seq_printf(m, "total: %lu, used %lu free %lu\n", total, total_used, total_free);

	return 0;

}

EXPORT_SYMBOL(drm_mm_dump_table);

#endif