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-rw-r--r--lib/genalloc.c216
1 files changed, 216 insertions, 0 deletions
diff --git a/lib/genalloc.c b/lib/genalloc.c
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index 00000000..577ddf80
--- /dev/null
+++ b/lib/genalloc.c
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+/*
+ * 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.
+ *
+ * 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/slab.h>
+#include <linux/module.h>
+#include <linux/bitmap.h>
+#include <linux/genalloc.h>
+
+
+/**
+ * gen_pool_create - create a new special memory pool
+ * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
+ * @nid: node id of the node the pool structure should be allocated on, or -1
+ *
+ * Create a new special memory pool that can be used to manage special purpose
+ * memory not managed by the regular kmalloc/kfree interface.
+ */
+struct gen_pool *gen_pool_create(int min_alloc_order, int nid)
+{
+ struct gen_pool *pool;
+
+ pool = kmalloc_node(sizeof(struct gen_pool), GFP_KERNEL, nid);
+ if (pool != NULL) {
+ rwlock_init(&pool->lock);
+ INIT_LIST_HEAD(&pool->chunks);
+ pool->min_alloc_order = min_alloc_order;
+ }
+ return pool;
+}
+EXPORT_SYMBOL(gen_pool_create);
+
+/**
+ * gen_pool_add_virt - add a new chunk of special memory to the pool
+ * @pool: pool to add new memory chunk to
+ * @virt: virtual starting address of memory chunk to add to pool
+ * @phys: physical starting address of memory chunk to add to pool
+ * @size: size in bytes of the memory chunk to add to pool
+ * @nid: node id of the node the chunk structure and bitmap should be
+ * allocated on, or -1
+ *
+ * Add a new chunk of special memory to the specified pool.
+ *
+ * Returns 0 on success or a -ve errno on failure.
+ */
+int gen_pool_add_virt(struct gen_pool *pool, unsigned long virt, phys_addr_t phys,
+ size_t size, int nid)
+{
+ struct gen_pool_chunk *chunk;
+ int nbits = size >> pool->min_alloc_order;
+ int nbytes = sizeof(struct gen_pool_chunk) +
+ (nbits + BITS_PER_BYTE - 1) / BITS_PER_BYTE;
+
+ chunk = kmalloc_node(nbytes, GFP_KERNEL | __GFP_ZERO, nid);
+ if (unlikely(chunk == NULL))
+ return -ENOMEM;
+
+ spin_lock_init(&chunk->lock);
+ chunk->phys_addr = phys;
+ chunk->start_addr = virt;
+ chunk->end_addr = virt + size;
+
+ write_lock(&pool->lock);
+ list_add(&chunk->next_chunk, &pool->chunks);
+ write_unlock(&pool->lock);
+
+ return 0;
+}
+EXPORT_SYMBOL(gen_pool_add_virt);
+
+/**
+ * gen_pool_virt_to_phys - return the physical address of memory
+ * @pool: pool to allocate from
+ * @addr: starting address of memory
+ *
+ * Returns the physical address on success, or -1 on error.
+ */
+phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long addr)
+{
+ struct list_head *_chunk;
+ struct gen_pool_chunk *chunk;
+
+ read_lock(&pool->lock);
+ list_for_each(_chunk, &pool->chunks) {
+ chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
+
+ if (addr >= chunk->start_addr && addr < chunk->end_addr)
+ return chunk->phys_addr + addr - chunk->start_addr;
+ }
+ read_unlock(&pool->lock);
+
+ return -1;
+}
+EXPORT_SYMBOL(gen_pool_virt_to_phys);
+
+/**
+ * gen_pool_destroy - destroy a special memory pool
+ * @pool: pool to destroy
+ *
+ * Destroy the specified special memory pool. Verifies that there are no
+ * outstanding allocations.
+ */
+void gen_pool_destroy(struct gen_pool *pool)
+{
+ struct list_head *_chunk, *_next_chunk;
+ struct gen_pool_chunk *chunk;
+ int order = pool->min_alloc_order;
+ int bit, end_bit;
+
+
+ list_for_each_safe(_chunk, _next_chunk, &pool->chunks) {
+ chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
+ list_del(&chunk->next_chunk);
+
+ end_bit = (chunk->end_addr - chunk->start_addr) >> order;
+ bit = find_next_bit(chunk->bits, end_bit, 0);
+ BUG_ON(bit < end_bit);
+
+ kfree(chunk);
+ }
+ kfree(pool);
+ return;
+}
+EXPORT_SYMBOL(gen_pool_destroy);
+
+/**
+ * gen_pool_alloc - allocate special memory from the pool
+ * @pool: pool to allocate from
+ * @size: number of bytes to allocate from the pool
+ *
+ * Allocate the requested number of bytes from the specified pool.
+ * Uses a first-fit algorithm.
+ */
+unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size)
+{
+ struct list_head *_chunk;
+ struct gen_pool_chunk *chunk;
+ unsigned long addr, flags;
+ int order = pool->min_alloc_order;
+ int nbits, start_bit, end_bit;
+
+ if (size == 0)
+ return 0;
+
+ nbits = (size + (1UL << order) - 1) >> order;
+
+ read_lock(&pool->lock);
+ list_for_each(_chunk, &pool->chunks) {
+ chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
+
+ end_bit = (chunk->end_addr - chunk->start_addr) >> order;
+
+ spin_lock_irqsave(&chunk->lock, flags);
+ start_bit = bitmap_find_next_zero_area(chunk->bits, end_bit, 0,
+ nbits, 0);
+ if (start_bit >= end_bit) {
+ spin_unlock_irqrestore(&chunk->lock, flags);
+ continue;
+ }
+
+ addr = chunk->start_addr + ((unsigned long)start_bit << order);
+
+ bitmap_set(chunk->bits, start_bit, nbits);
+ spin_unlock_irqrestore(&chunk->lock, flags);
+ read_unlock(&pool->lock);
+ return addr;
+ }
+ read_unlock(&pool->lock);
+ return 0;
+}
+EXPORT_SYMBOL(gen_pool_alloc);
+
+/**
+ * gen_pool_free - free allocated special memory back to the pool
+ * @pool: pool to free to
+ * @addr: starting address of memory to free back to pool
+ * @size: size in bytes of memory to free
+ *
+ * Free previously allocated special memory back to the specified pool.
+ */
+void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size)
+{
+ struct list_head *_chunk;
+ struct gen_pool_chunk *chunk;
+ unsigned long flags;
+ int order = pool->min_alloc_order;
+ int bit, nbits;
+
+ nbits = (size + (1UL << order) - 1) >> order;
+
+ read_lock(&pool->lock);
+ list_for_each(_chunk, &pool->chunks) {
+ chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
+
+ if (addr >= chunk->start_addr && addr < chunk->end_addr) {
+ BUG_ON(addr + size > chunk->end_addr);
+ spin_lock_irqsave(&chunk->lock, flags);
+ bit = (addr - chunk->start_addr) >> order;
+ while (nbits--)
+ __clear_bit(bit++, chunk->bits);
+ spin_unlock_irqrestore(&chunk->lock, flags);
+ break;
+ }
+ }
+ BUG_ON(nbits > 0);
+ read_unlock(&pool->lock);
+}
+EXPORT_SYMBOL(gen_pool_free);