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Matthew Wilcox6182a092007-12-03 12:16:57 -05001/*
2 * DMA Pool allocator
3 *
4 * Copyright 2001 David Brownell
5 * Copyright 2007 Intel Corporation
6 * Author: Matthew Wilcox <willy@linux.intel.com>
7 *
8 * This software may be redistributed and/or modified under the terms of
9 * the GNU General Public License ("GPL") version 2 as published by the
10 * Free Software Foundation.
11 *
12 * This allocator returns small blocks of a given size which are DMA-able by
13 * the given device. It uses the dma_alloc_coherent page allocator to get
14 * new pages, then splits them up into blocks of the required size.
15 * Many older drivers still have their own code to do this.
16 *
17 * The current design of this allocator is fairly simple. The pool is
18 * represented by the 'struct dma_pool' which keeps a doubly-linked list of
19 * allocated pages. Each page in the page_list is split into blocks of at
Matthew Wilcoxa35a3452007-12-03 14:08:28 -050020 * least 'size' bytes. Free blocks are tracked in an unsorted singly-linked
21 * list of free blocks within the page. Used blocks aren't tracked, but we
22 * keep a count of how many are currently allocated from each page.
Matthew Wilcox6182a092007-12-03 12:16:57 -050023 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070024
25#include <linux/device.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include <linux/dma-mapping.h>
27#include <linux/dmapool.h>
Matthew Wilcox6182a092007-12-03 12:16:57 -050028#include <linux/kernel.h>
29#include <linux/list.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030#include <linux/module.h>
Matthew Wilcox6182a092007-12-03 12:16:57 -050031#include <linux/mutex.h>
Randy Dunlapc9cf5522006-06-27 02:53:52 -070032#include <linux/poison.h>
Alexey Dobriyane8edc6e2007-05-21 01:22:52 +040033#include <linux/sched.h>
Matthew Wilcox6182a092007-12-03 12:16:57 -050034#include <linux/slab.h>
35#include <linux/spinlock.h>
36#include <linux/string.h>
37#include <linux/types.h>
38#include <linux/wait.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070039
Andi Kleenb5ee5be2008-04-28 02:12:37 -070040#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB_DEBUG_ON)
41#define DMAPOOL_DEBUG 1
42#endif
43
Matthew Wilcoxe87aa772007-12-03 12:04:31 -050044struct dma_pool { /* the pool */
45 struct list_head page_list;
46 spinlock_t lock;
Matthew Wilcoxe87aa772007-12-03 12:04:31 -050047 size_t size;
48 struct device *dev;
49 size_t allocation;
Matthew Wilcoxe34f44b2007-12-03 14:16:24 -050050 size_t boundary;
Matthew Wilcoxe87aa772007-12-03 12:04:31 -050051 char name[32];
52 wait_queue_head_t waitq;
53 struct list_head pools;
Linus Torvalds1da177e2005-04-16 15:20:36 -070054};
55
Matthew Wilcoxe87aa772007-12-03 12:04:31 -050056struct dma_page { /* cacheable header for 'allocation' bytes */
57 struct list_head page_list;
58 void *vaddr;
59 dma_addr_t dma;
Matthew Wilcoxa35a3452007-12-03 14:08:28 -050060 unsigned int in_use;
61 unsigned int offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -070062};
63
64#define POOL_TIMEOUT_JIFFIES ((100 /* msec */ * HZ) / 1000)
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
Matthew Wilcoxe87aa772007-12-03 12:04:31 -050066static DEFINE_MUTEX(pools_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070067
68static ssize_t
Matthew Wilcoxe87aa772007-12-03 12:04:31 -050069show_pools(struct device *dev, struct device_attribute *attr, char *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -070070{
71 unsigned temp;
72 unsigned size;
73 char *next;
74 struct dma_page *page;
75 struct dma_pool *pool;
76
77 next = buf;
78 size = PAGE_SIZE;
79
80 temp = scnprintf(next, size, "poolinfo - 0.1\n");
81 size -= temp;
82 next += temp;
83
Matthias Kaehlckeb2366d62007-04-24 22:45:25 +020084 mutex_lock(&pools_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070085 list_for_each_entry(pool, &dev->dma_pools, pools) {
86 unsigned pages = 0;
87 unsigned blocks = 0;
88
Thomas Gleixnerc4956822009-06-30 11:41:25 -070089 spin_lock_irq(&pool->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 list_for_each_entry(page, &pool->page_list, page_list) {
91 pages++;
92 blocks += page->in_use;
93 }
Thomas Gleixnerc4956822009-06-30 11:41:25 -070094 spin_unlock_irq(&pool->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070095
96 /* per-pool info, no real statistics yet */
97 temp = scnprintf(next, size, "%-16s %4u %4Zu %4Zu %2u\n",
Matthew Wilcoxa35a3452007-12-03 14:08:28 -050098 pool->name, blocks,
99 pages * (pool->allocation / pool->size),
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500100 pool->size, pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 size -= temp;
102 next += temp;
103 }
Matthias Kaehlckeb2366d62007-04-24 22:45:25 +0200104 mutex_unlock(&pools_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105
106 return PAGE_SIZE - size;
107}
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500108
109static DEVICE_ATTR(pools, S_IRUGO, show_pools, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110
111/**
112 * dma_pool_create - Creates a pool of consistent memory blocks, for dma.
113 * @name: name of pool, for diagnostics
114 * @dev: device that will be doing the DMA
115 * @size: size of the blocks in this pool.
116 * @align: alignment requirement for blocks; must be a power of two
Matthew Wilcoxe34f44b2007-12-03 14:16:24 -0500117 * @boundary: returned blocks won't cross this power of two boundary
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 * Context: !in_interrupt()
119 *
120 * Returns a dma allocation pool with the requested characteristics, or
121 * null if one can't be created. Given one of these pools, dma_pool_alloc()
122 * may be used to allocate memory. Such memory will all have "consistent"
123 * DMA mappings, accessible by the device and its driver without using
124 * cache flushing primitives. The actual size of blocks allocated may be
125 * larger than requested because of alignment.
126 *
Matthew Wilcoxe34f44b2007-12-03 14:16:24 -0500127 * If @boundary is nonzero, objects returned from dma_pool_alloc() won't
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 * cross that size boundary. This is useful for devices which have
129 * addressing restrictions on individual DMA transfers, such as not crossing
130 * boundaries of 4KBytes.
131 */
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500132struct dma_pool *dma_pool_create(const char *name, struct device *dev,
Matthew Wilcoxe34f44b2007-12-03 14:16:24 -0500133 size_t size, size_t align, size_t boundary)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134{
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500135 struct dma_pool *retval;
Matthew Wilcoxe34f44b2007-12-03 14:16:24 -0500136 size_t allocation;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137
Matthew Wilcox399154b2007-12-03 12:10:24 -0500138 if (align == 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 align = 1;
Matthew Wilcox399154b2007-12-03 12:10:24 -0500140 } else if (align & (align - 1)) {
141 return NULL;
142 }
143
Matthew Wilcoxa35a3452007-12-03 14:08:28 -0500144 if (size == 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145 return NULL;
Matthew Wilcoxa35a3452007-12-03 14:08:28 -0500146 } else if (size < 4) {
147 size = 4;
148 }
Matthew Wilcox399154b2007-12-03 12:10:24 -0500149
150 if ((size % align) != 0)
151 size = ALIGN(size, align);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152
Matthew Wilcoxe34f44b2007-12-03 14:16:24 -0500153 allocation = max_t(size_t, size, PAGE_SIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154
Matthew Wilcoxe34f44b2007-12-03 14:16:24 -0500155 if (!boundary) {
156 boundary = allocation;
157 } else if ((boundary < size) || (boundary & (boundary - 1))) {
158 return NULL;
159 }
160
161 retval = kmalloc_node(sizeof(*retval), GFP_KERNEL, dev_to_node(dev));
162 if (!retval)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163 return retval;
164
Matthew Wilcoxe34f44b2007-12-03 14:16:24 -0500165 strlcpy(retval->name, name, sizeof(retval->name));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166
167 retval->dev = dev;
168
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500169 INIT_LIST_HEAD(&retval->page_list);
170 spin_lock_init(&retval->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171 retval->size = size;
Matthew Wilcoxe34f44b2007-12-03 14:16:24 -0500172 retval->boundary = boundary;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173 retval->allocation = allocation;
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500174 init_waitqueue_head(&retval->waitq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175
176 if (dev) {
Cornelia Huck141ecc52006-09-22 11:37:27 +0200177 int ret;
178
Matthias Kaehlckeb2366d62007-04-24 22:45:25 +0200179 mutex_lock(&pools_lock);
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500180 if (list_empty(&dev->dma_pools))
181 ret = device_create_file(dev, &dev_attr_pools);
Cornelia Huck141ecc52006-09-22 11:37:27 +0200182 else
183 ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 /* note: not currently insisting "name" be unique */
Cornelia Huck141ecc52006-09-22 11:37:27 +0200185 if (!ret)
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500186 list_add(&retval->pools, &dev->dma_pools);
Cornelia Huck141ecc52006-09-22 11:37:27 +0200187 else {
188 kfree(retval);
189 retval = NULL;
190 }
Matthias Kaehlckeb2366d62007-04-24 22:45:25 +0200191 mutex_unlock(&pools_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192 } else
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500193 INIT_LIST_HEAD(&retval->pools);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194
195 return retval;
196}
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500197EXPORT_SYMBOL(dma_pool_create);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198
Matthew Wilcoxa35a3452007-12-03 14:08:28 -0500199static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page)
200{
201 unsigned int offset = 0;
Matthew Wilcoxe34f44b2007-12-03 14:16:24 -0500202 unsigned int next_boundary = pool->boundary;
Matthew Wilcoxa35a3452007-12-03 14:08:28 -0500203
204 do {
205 unsigned int next = offset + pool->size;
Matthew Wilcoxe34f44b2007-12-03 14:16:24 -0500206 if (unlikely((next + pool->size) >= next_boundary)) {
207 next = next_boundary;
208 next_boundary += pool->boundary;
209 }
Matthew Wilcoxa35a3452007-12-03 14:08:28 -0500210 *(int *)(page->vaddr + offset) = next;
211 offset = next;
212 } while (offset < pool->allocation);
213}
214
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500215static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216{
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500217 struct dma_page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218
Matthew Wilcoxa35a3452007-12-03 14:08:28 -0500219 page = kmalloc(sizeof(*page), mem_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 if (!page)
221 return NULL;
Matthew Wilcoxa35a3452007-12-03 14:08:28 -0500222 page->vaddr = dma_alloc_coherent(pool->dev, pool->allocation,
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500223 &page->dma, mem_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 if (page->vaddr) {
Andi Kleenb5ee5be2008-04-28 02:12:37 -0700225#ifdef DMAPOOL_DEBUG
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500226 memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227#endif
Matthew Wilcoxa35a3452007-12-03 14:08:28 -0500228 pool_initialise_page(pool, page);
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500229 list_add(&page->page_list, &pool->page_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230 page->in_use = 0;
Matthew Wilcoxa35a3452007-12-03 14:08:28 -0500231 page->offset = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232 } else {
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500233 kfree(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 page = NULL;
235 }
236 return page;
237}
238
Matthew Wilcoxa35a3452007-12-03 14:08:28 -0500239static inline int is_page_busy(struct dma_page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240{
Matthew Wilcoxa35a3452007-12-03 14:08:28 -0500241 return page->in_use != 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242}
243
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500244static void pool_free_page(struct dma_pool *pool, struct dma_page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245{
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500246 dma_addr_t dma = page->dma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247
Andi Kleenb5ee5be2008-04-28 02:12:37 -0700248#ifdef DMAPOOL_DEBUG
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500249 memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250#endif
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500251 dma_free_coherent(pool->dev, pool->allocation, page->vaddr, dma);
252 list_del(&page->page_list);
253 kfree(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254}
255
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256/**
257 * dma_pool_destroy - destroys a pool of dma memory blocks.
258 * @pool: dma pool that will be destroyed
259 * Context: !in_interrupt()
260 *
261 * Caller guarantees that no more memory from the pool is in use,
262 * and that nothing will try to use the pool after this call.
263 */
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500264void dma_pool_destroy(struct dma_pool *pool)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265{
Matthias Kaehlckeb2366d62007-04-24 22:45:25 +0200266 mutex_lock(&pools_lock);
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500267 list_del(&pool->pools);
268 if (pool->dev && list_empty(&pool->dev->dma_pools))
269 device_remove_file(pool->dev, &dev_attr_pools);
Matthias Kaehlckeb2366d62007-04-24 22:45:25 +0200270 mutex_unlock(&pools_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500272 while (!list_empty(&pool->page_list)) {
273 struct dma_page *page;
274 page = list_entry(pool->page_list.next,
275 struct dma_page, page_list);
Matthew Wilcoxa35a3452007-12-03 14:08:28 -0500276 if (is_page_busy(page)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 if (pool->dev)
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500278 dev_err(pool->dev,
279 "dma_pool_destroy %s, %p busy\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280 pool->name, page->vaddr);
281 else
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500282 printk(KERN_ERR
283 "dma_pool_destroy %s, %p busy\n",
284 pool->name, page->vaddr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285 /* leak the still-in-use consistent memory */
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500286 list_del(&page->page_list);
287 kfree(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288 } else
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500289 pool_free_page(pool, page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 }
291
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500292 kfree(pool);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293}
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500294EXPORT_SYMBOL(dma_pool_destroy);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295
296/**
297 * dma_pool_alloc - get a block of consistent memory
298 * @pool: dma pool that will produce the block
299 * @mem_flags: GFP_* bitmask
300 * @handle: pointer to dma address of block
301 *
302 * This returns the kernel virtual address of a currently unused block,
303 * and reports its dma address through the handle.
Matthew Wilcox6182a092007-12-03 12:16:57 -0500304 * If such a memory block can't be allocated, %NULL is returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305 */
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500306void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags,
307 dma_addr_t *handle)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308{
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500309 unsigned long flags;
310 struct dma_page *page;
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500311 size_t offset;
312 void *retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313
Dima Zavinea05c842010-10-26 14:21:54 -0700314 might_sleep_if(mem_flags & __GFP_WAIT);
315
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500316 spin_lock_irqsave(&pool->lock, flags);
Matthew Wilcox2cae3672007-12-03 12:09:33 -0500317 restart:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318 list_for_each_entry(page, &pool->page_list, page_list) {
Matthew Wilcoxa35a3452007-12-03 14:08:28 -0500319 if (page->offset < pool->allocation)
320 goto ready;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 }
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500322 page = pool_alloc_page(pool, GFP_ATOMIC);
323 if (!page) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324 if (mem_flags & __GFP_WAIT) {
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500325 DECLARE_WAITQUEUE(wait, current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326
Arjan van de Vend9aaccc2007-10-16 23:29:32 -0700327 __set_current_state(TASK_INTERRUPTIBLE);
Matthew Wilcox2cae3672007-12-03 12:09:33 -0500328 __add_wait_queue(&pool->waitq, &wait);
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500329 spin_unlock_irqrestore(&pool->lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500331 schedule_timeout(POOL_TIMEOUT_JIFFIES);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332
Matthew Wilcox2cae3672007-12-03 12:09:33 -0500333 spin_lock_irqsave(&pool->lock, flags);
334 __remove_wait_queue(&pool->waitq, &wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 goto restart;
336 }
337 retval = NULL;
338 goto done;
339 }
340
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500341 ready:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 page->in_use++;
Matthew Wilcoxa35a3452007-12-03 14:08:28 -0500343 offset = page->offset;
344 page->offset = *(int *)(page->vaddr + offset);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 retval = offset + page->vaddr;
346 *handle = offset + page->dma;
Andi Kleenb5ee5be2008-04-28 02:12:37 -0700347#ifdef DMAPOOL_DEBUG
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500348 memset(retval, POOL_POISON_ALLOCATED, pool->size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349#endif
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500350 done:
351 spin_unlock_irqrestore(&pool->lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352 return retval;
353}
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500354EXPORT_SYMBOL(dma_pool_alloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500356static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357{
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500358 struct dma_page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360 list_for_each_entry(page, &pool->page_list, page_list) {
361 if (dma < page->dma)
362 continue;
363 if (dma < (page->dma + pool->allocation))
Rolf Eike Beer84bc2272011-01-13 15:47:24 -0800364 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 }
Rolf Eike Beer84bc2272011-01-13 15:47:24 -0800366 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700367}
368
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369/**
370 * dma_pool_free - put block back into dma pool
371 * @pool: the dma pool holding the block
372 * @vaddr: virtual address of block
373 * @dma: dma address of block
374 *
375 * Caller promises neither device nor driver will again touch this block
376 * unless it is first re-allocated.
377 */
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500378void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379{
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500380 struct dma_page *page;
381 unsigned long flags;
Matthew Wilcoxa35a3452007-12-03 14:08:28 -0500382 unsigned int offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383
Rolf Eike Beer84bc2272011-01-13 15:47:24 -0800384 spin_lock_irqsave(&pool->lock, flags);
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500385 page = pool_find_page(pool, dma);
386 if (!page) {
Rolf Eike Beer84bc2272011-01-13 15:47:24 -0800387 spin_unlock_irqrestore(&pool->lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 if (pool->dev)
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500389 dev_err(pool->dev,
390 "dma_pool_free %s, %p/%lx (bad dma)\n",
391 pool->name, vaddr, (unsigned long)dma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392 else
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500393 printk(KERN_ERR "dma_pool_free %s, %p/%lx (bad dma)\n",
394 pool->name, vaddr, (unsigned long)dma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395 return;
396 }
397
Matthew Wilcoxa35a3452007-12-03 14:08:28 -0500398 offset = vaddr - page->vaddr;
Andi Kleenb5ee5be2008-04-28 02:12:37 -0700399#ifdef DMAPOOL_DEBUG
Matthew Wilcoxa35a3452007-12-03 14:08:28 -0500400 if ((dma - page->dma) != offset) {
Rolf Eike Beer84bc2272011-01-13 15:47:24 -0800401 spin_unlock_irqrestore(&pool->lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402 if (pool->dev)
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500403 dev_err(pool->dev,
404 "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
405 pool->name, vaddr, (unsigned long long)dma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 else
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500407 printk(KERN_ERR
408 "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
409 pool->name, vaddr, (unsigned long long)dma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410 return;
411 }
Matthew Wilcoxa35a3452007-12-03 14:08:28 -0500412 {
413 unsigned int chain = page->offset;
414 while (chain < pool->allocation) {
415 if (chain != offset) {
416 chain = *(int *)(page->vaddr + chain);
417 continue;
418 }
Rolf Eike Beer84bc2272011-01-13 15:47:24 -0800419 spin_unlock_irqrestore(&pool->lock, flags);
Matthew Wilcoxa35a3452007-12-03 14:08:28 -0500420 if (pool->dev)
421 dev_err(pool->dev, "dma_pool_free %s, dma %Lx "
422 "already free\n", pool->name,
423 (unsigned long long)dma);
424 else
425 printk(KERN_ERR "dma_pool_free %s, dma %Lx "
426 "already free\n", pool->name,
427 (unsigned long long)dma);
428 return;
429 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430 }
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500431 memset(vaddr, POOL_POISON_FREED, pool->size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432#endif
433
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434 page->in_use--;
Matthew Wilcoxa35a3452007-12-03 14:08:28 -0500435 *(int *)vaddr = page->offset;
436 page->offset = offset;
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500437 if (waitqueue_active(&pool->waitq))
Matthew Wilcox2cae3672007-12-03 12:09:33 -0500438 wake_up_locked(&pool->waitq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439 /*
440 * Resist a temptation to do
Matthew Wilcoxa35a3452007-12-03 14:08:28 -0500441 * if (!is_page_busy(page)) pool_free_page(pool, page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442 * Better have a few empty pages hang around.
443 */
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500444 spin_unlock_irqrestore(&pool->lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445}
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500446EXPORT_SYMBOL(dma_pool_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447
Tejun Heo9ac78492007-01-20 16:00:26 +0900448/*
449 * Managed DMA pool
450 */
451static void dmam_pool_release(struct device *dev, void *res)
452{
453 struct dma_pool *pool = *(struct dma_pool **)res;
454
455 dma_pool_destroy(pool);
456}
457
458static int dmam_pool_match(struct device *dev, void *res, void *match_data)
459{
460 return *(struct dma_pool **)res == match_data;
461}
462
463/**
464 * dmam_pool_create - Managed dma_pool_create()
465 * @name: name of pool, for diagnostics
466 * @dev: device that will be doing the DMA
467 * @size: size of the blocks in this pool.
468 * @align: alignment requirement for blocks; must be a power of two
469 * @allocation: returned blocks won't cross this boundary (or zero)
470 *
471 * Managed dma_pool_create(). DMA pool created with this function is
472 * automatically destroyed on driver detach.
473 */
474struct dma_pool *dmam_pool_create(const char *name, struct device *dev,
475 size_t size, size_t align, size_t allocation)
476{
477 struct dma_pool **ptr, *pool;
478
479 ptr = devres_alloc(dmam_pool_release, sizeof(*ptr), GFP_KERNEL);
480 if (!ptr)
481 return NULL;
482
483 pool = *ptr = dma_pool_create(name, dev, size, align, allocation);
484 if (pool)
485 devres_add(dev, ptr);
486 else
487 devres_free(ptr);
488
489 return pool;
490}
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500491EXPORT_SYMBOL(dmam_pool_create);
Tejun Heo9ac78492007-01-20 16:00:26 +0900492
493/**
494 * dmam_pool_destroy - Managed dma_pool_destroy()
495 * @pool: dma pool that will be destroyed
496 *
497 * Managed dma_pool_destroy().
498 */
499void dmam_pool_destroy(struct dma_pool *pool)
500{
501 struct device *dev = pool->dev;
502
503 dma_pool_destroy(pool);
504 WARN_ON(devres_destroy(dev, dmam_pool_release, dmam_pool_match, pool));
505}
Matthew Wilcoxe87aa772007-12-03 12:04:31 -0500506EXPORT_SYMBOL(dmam_pool_destroy);