3 files changed, 195 insertions, 0 deletions

diff --git a/lib/Kconfig b/lib/Kconfig
index eeb45225248f..2d4d4e3bc4aa 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -40,6 +40,12 @@ config ZLIB_DEFLATE
         tristate
 
 #
+# Generic allocator support is selected if needed
+#
+config GENERIC_ALLOCATOR
+        boolean
+
+#
 # reed solomon support is select'ed if needed
 #
 config REED_SOLOMON
diff --git a/lib/Makefile b/lib/Makefile
index 5f10cb898407..dcb4231916e2 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -30,6 +30,7 @@ obj-$(CONFIG_CRC_CCITT)	+= crc-ccitt.o
 obj-$(CONFIG_CRC32)     += crc32.o
 obj-$(CONFIG_LIBCRC32C) += libcrc32c.o
 obj-$(CONFIG_GENERIC_IOMAP) += iomap.o
+obj-$(CONFIG_GENERIC_ALLOCATOR) += genalloc.o
 
 obj-$(CONFIG_ZLIB_INFLATE) += zlib_inflate/
 obj-$(CONFIG_ZLIB_DEFLATE) += zlib_deflate/
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);