drm: add simple DRM memory manager, and hash table

This adds the DRM hashtable and simple memory manager implementations from
Tungsten Graphics, this is NOT the new memory manager, this is a replacement
for the SIS and VIA memory managers.

Signed-off-by: Dave Airlie <airlied@linux.ie>

1 files changed, 201 insertions, 0 deletions

diff --git a/drivers/char/drm/drm_mm.c b/drivers/char/drm/drm_mm.c
new file mode 100644
index 000000000000..c55ed45a8944
--- /dev/null
+++ b/drivers/char/drm/drm_mm.c
@@ -0,0 +1,201 @@
+/**************************************************************************
+ *
+ * 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 <thomas-at-tungstengraphics-dot-com>
+ */
+
+#include "drmP.h"
+
+drm_mm_node_t *drm_mm_get_block(drm_mm_node_t * parent,
+				unsigned long size, unsigned alignment)
+{
+
+	drm_mm_node_t *child;
+
+	if (alignment)
+		size += alignment - 1;
+
+	if (parent->size == size) {
+		list_del_init(&parent->fl_entry);
+		parent->free = FALSE;
+		return parent;
+	} else {
+		child = (drm_mm_node_t *) drm_alloc(sizeof(*child), DRM_MEM_MM);
+		if (!child)
+			return NULL;
+
+		INIT_LIST_HEAD(&child->ml_entry);
+		INIT_LIST_HEAD(&child->fl_entry);
+
+		child->free = FALSE;
+		child->size = size;
+		child->start = parent->start;
+
+		list_add_tail(&child->ml_entry, &parent->ml_entry);
+		parent->size -= size;
+		parent->start += size;
+	}
+	return child;
+}
+
+/*
+ * Put a block. Merge with the previous and / or next block if they are free.
+ * Otherwise add to the free stack.
+ */
+
+void drm_mm_put_block(drm_mm_t * mm, drm_mm_node_t * cur)
+{
+
+	drm_mm_node_t *list_root = &mm->root_node;
+	struct list_head *cur_head = &cur->ml_entry;
+	struct list_head *root_head = &list_root->ml_entry;
+	drm_mm_node_t *prev_node = NULL;
+	drm_mm_node_t *next_node;
+
+	int merged = FALSE;
+
+	if (cur_head->prev != root_head) {
+		prev_node = list_entry(cur_head->prev, drm_mm_node_t, ml_entry);
+		if (prev_node->free) {
+			prev_node->size += cur->size;
+			merged = TRUE;
+		}
+	}
+	if (cur_head->next != root_head) {
+		next_node = list_entry(cur_head->next, drm_mm_node_t, ml_entry);
+		if (next_node->free) {
+			if (merged) {
+				prev_node->size += next_node->size;
+				list_del(&next_node->ml_entry);
+				list_del(&next_node->fl_entry);
+				drm_free(next_node, sizeof(*next_node),
+					 DRM_MEM_MM);
+			} else {
+				next_node->size += cur->size;
+				next_node->start = cur->start;
+				merged = TRUE;
+			}
+		}
+	}
+	if (!merged) {
+		cur->free = TRUE;
+		list_add(&cur->fl_entry, &list_root->fl_entry);
+	} else {
+		list_del(&cur->ml_entry);
+		drm_free(cur, sizeof(*cur), DRM_MEM_MM);
+	}
+}
+
+drm_mm_node_t *drm_mm_search_free(const drm_mm_t * mm,
+				  unsigned long size,
+				  unsigned alignment, int best_match)
+{
+	struct list_head *list;
+	const struct list_head *free_stack = &mm->root_node.fl_entry;
+	drm_mm_node_t *entry;
+	drm_mm_node_t *best;
+	unsigned long best_size;
+
+	best = NULL;
+	best_size = ~0UL;
+
+	if (alignment)
+		size += alignment - 1;
+
+	list_for_each(list, free_stack) {
+		entry = list_entry(list, drm_mm_node_t, fl_entry);
+		if (entry->size >= size) {
+			if (!best_match)
+				return entry;
+			if (size < best_size) {
+				best = entry;
+				best_size = entry->size;
+			}
+		}
+	}
+
+	return best;
+}
+
+int drm_mm_init(drm_mm_t * mm, unsigned long start, unsigned long size)
+{
+	drm_mm_node_t *child;
+
+	INIT_LIST_HEAD(&mm->root_node.ml_entry);
+	INIT_LIST_HEAD(&mm->root_node.fl_entry);
+	child = (drm_mm_node_t *) drm_alloc(sizeof(*child), DRM_MEM_MM);
+	if (!child)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&child->ml_entry);
+	INIT_LIST_HEAD(&child->fl_entry);
+
+	child->start = start;
+	child->size = size;
+	child->free = TRUE;
+
+	list_add(&child->fl_entry, &mm->root_node.fl_entry);
+	list_add(&child->ml_entry, &mm->root_node.ml_entry);
+
+	return 0;
+}
+
+EXPORT_SYMBOL(drm_mm_init);
+
+void drm_mm_takedown(drm_mm_t * mm)
+{
+	struct list_head *bnode = mm->root_node.fl_entry.next;
+	drm_mm_node_t *entry;
+
+	entry = list_entry(bnode, drm_mm_node_t, fl_entry);
+
+	if (entry->ml_entry.next != &mm->root_node.ml_entry ||
+	    entry->fl_entry.next != &mm->root_node.fl_entry) {
+		DRM_ERROR("Memory manager not clean. Delaying takedown\n");
+		return;
+	}
+
+	list_del(&entry->fl_entry);
+	list_del(&entry->ml_entry);
+
+	drm_free(entry, sizeof(*entry), DRM_MEM_MM);
+}
+
+EXPORT_SYMBOL(drm_mm_takedown);