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-rw-r--r--lib/genalloc.c188
1 files changed, 188 insertions, 0 deletions
diff --git a/lib/genalloc.c b/lib/genalloc.c
new file mode 100644
index 000000000000..d6d30d2e7166
--- /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);

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