1 files changed, 188 insertions, 0 deletions
diff --git a/lib/genalloc.c b/lib/genalloc.c
new file mode 100644
index 0000000..d6d30d2e
--- /dev/null
+++ b/lib/genalloc.c
@@ -0,0 +1,188 @@
+/*
+ * Basic general purpose allocator for managing special purpose memory
+ * not managed by the regular kmalloc/kfree interface.
+ * Uses for this includes on-device special memory, uncached memory
+ * etc.
+ *
+ * This code is based on the buddy allocator found in the sym53c8xx_2
+ * driver Copyright (C) 1999-2001  Gerard Roudier <groudier@free.fr>,
+ * and adapted for general purpose use.
+ *
+ * Copyright 2005 (C) Jes Sorensen <jes@trained-monkey.org>
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2.  See the file COPYING for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/stddef.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/spinlock.h>
+#include <linux/genalloc.h>
+
+#include <asm/page.h>
+
+
+struct gen_pool *gen_pool_create(int nr_chunks, int max_chunk_shift,
+				 unsigned long (*fp)(struct gen_pool *),
+				 unsigned long data)
+{
+	struct gen_pool *poolp;
+	unsigned long tmp;
+	int i;
+
+	/*
+	 * This is really an arbitrary limit, +10 is enough for
+	 * IA64_GRANULE_SHIFT, aka 16MB. If anyone needs a large limit
+	 * this can be increased without problems.
+	 */
+	if ((max_chunk_shift > (PAGE_SHIFT + 10)) ||
+	    ((max_chunk_shift < ALLOC_MIN_SHIFT) && max_chunk_shift))
+		return NULL;
+
+	if (!max_chunk_shift)
+		max_chunk_shift = PAGE_SHIFT;
+
+	poolp = kmalloc(sizeof(struct gen_pool), GFP_KERNEL);
+	if (!poolp)
+		return NULL;
+	memset(poolp, 0, sizeof(struct gen_pool));
+	poolp->h = kmalloc(sizeof(struct gen_pool_link) *
+			   (max_chunk_shift - ALLOC_MIN_SHIFT + 1),
+			   GFP_KERNEL);
+	if (!poolp->h) {
+		printk(KERN_WARNING "gen_pool_alloc() failed to allocate\n");
+		kfree(poolp);
+		return NULL;
+	}
+	memset(poolp->h, 0, sizeof(struct gen_pool_link) *
+	       (max_chunk_shift - ALLOC_MIN_SHIFT + 1));
+
+	spin_lock_init(&poolp->lock);
+	poolp->get_new_chunk = fp;
+	poolp->max_chunk_shift = max_chunk_shift;
+	poolp->private = data;
+
+	for (i = 0; i < nr_chunks; i++) {
+		tmp = poolp->get_new_chunk(poolp);
+		printk(KERN_INFO "allocated %lx\n", tmp);
+		if (!tmp)
+			break;
+		gen_pool_free(poolp, tmp, (1 << poolp->max_chunk_shift));
+	}
+
+	return poolp;
+}
+EXPORT_SYMBOL(gen_pool_create);
+
+
+/*
+ *  Simple power of two buddy-like generic allocator.
+ *  Provides naturally aligned memory chunks.
+ */
+unsigned long gen_pool_alloc(struct gen_pool *poolp, int size)
+{
+	int j, i, s, max_chunk_size;
+	unsigned long a, flags;
+	struct gen_pool_link *h = poolp->h;
+
+	max_chunk_size = 1 << poolp->max_chunk_shift;
+
+	if (size > max_chunk_size)
+		return 0;
+
+	i = 0;
+
+	size = max(size, 1 << ALLOC_MIN_SHIFT);
+	s = roundup_pow_of_two(size);
+
+	j = i;
+
+	spin_lock_irqsave(&poolp->lock, flags);
+	while (!h[j].next) {
+		if (s == max_chunk_size) {
+			struct gen_pool_link *ptr;
+			spin_unlock_irqrestore(&poolp->lock, flags);
+			ptr = (struct gen_pool_link *)poolp->get_new_chunk(poolp);
+			spin_lock_irqsave(&poolp->lock, flags);
+			h[j].next = ptr;
+			if (h[j].next)
+				h[j].next->next = NULL;
+			break;
+		}
+		j++;
+		s <<= 1;
+	}
+	a = (unsigned long) h[j].next;
+	if (a) {
+		h[j].next = h[j].next->next;
+		/*
+		 * This should be split into a seperate function doing
+		 * the chunk split in order to support custom
+		 * handling memory not physically accessible by host
+		 */
+		while (j > i) {
+			j -= 1;
+			s >>= 1;
+			h[j].next = (struct gen_pool_link *) (a + s);
+			h[j].next->next = NULL;
+		}
+	}
+	spin_unlock_irqrestore(&poolp->lock, flags);
+	return a;
+}
+EXPORT_SYMBOL(gen_pool_alloc);
+
+
+/*
+ *  Counter-part of the generic allocator.
+ */
+void gen_pool_free(struct gen_pool *poolp, unsigned long ptr, int size)
+{
+	struct gen_pool_link *q;
+	struct gen_pool_link *h = poolp->h;
+	unsigned long a, b, flags;
+	int i, s, max_chunk_size;
+
+	max_chunk_size = 1 << poolp->max_chunk_shift;
+
+	if (size > max_chunk_size)
+		return;
+
+	i = 0;
+
+	size = max(size, 1 << ALLOC_MIN_SHIFT);
+	s = roundup_pow_of_two(size);
+
+	a = ptr;
+
+	spin_lock_irqsave(&poolp->lock, flags);
+	while (1) {
+		if (s == max_chunk_size) {
+			((struct gen_pool_link *)a)->next = h[i].next;
+			h[i].next = (struct gen_pool_link *)a;
+			break;
+		}
+		b = a ^ s;
+		q = &h[i];
+
+		while (q->next && q->next != (struct gen_pool_link *)b)
+			q = q->next;
+
+		if (!q->next) {
+			((struct gen_pool_link *)a)->next = h[i].next;
+			h[i].next = (struct gen_pool_link *)a;
+			break;
+		}
+		q->next = q->next->next;
+		a = a & b;
+		s <<= 1;
+		i++;
+	}
+	spin_unlock_irqrestore(&poolp->lock, flags);
+}
+EXPORT_SYMBOL(gen_pool_free);