2 #include <linux/device.h>
4 #include <asm/io.h> /* Needed for i386 to build */
5 #include <linux/dma-mapping.h>
6 #include <linux/dmapool.h>
7 #include <linux/slab.h>
8 #include <linux/module.h>
9 #include <linux/poison.h>
10 #include <linux/sched.h>
13 * Pool allocator ... wraps the dma_alloc_coherent page allocator, so
14 * small blocks are easily used by drivers for bus mastering controllers.
15 * This should probably be sharing the guts of the slab allocator.
18 struct dma_pool { /* the pool */
19 struct list_head page_list;
21 size_t blocks_per_page;
26 wait_queue_head_t waitq;
27 struct list_head pools;
30 struct dma_page { /* cacheable header for 'allocation' bytes */
31 struct list_head page_list;
35 unsigned long bitmap[0];
38 #define POOL_TIMEOUT_JIFFIES ((100 /* msec */ * HZ) / 1000)
40 static DEFINE_MUTEX(pools_lock);
43 show_pools(struct device *dev, struct device_attribute *attr, char *buf)
48 struct dma_page *page;
49 struct dma_pool *pool;
54 temp = scnprintf(next, size, "poolinfo - 0.1\n");
58 mutex_lock(&pools_lock);
59 list_for_each_entry(pool, &dev->dma_pools, pools) {
63 list_for_each_entry(page, &pool->page_list, page_list) {
65 blocks += page->in_use;
68 /* per-pool info, no real statistics yet */
69 temp = scnprintf(next, size, "%-16s %4u %4Zu %4Zu %2u\n",
71 blocks, pages * pool->blocks_per_page,
76 mutex_unlock(&pools_lock);
78 return PAGE_SIZE - size;
81 static DEVICE_ATTR(pools, S_IRUGO, show_pools, NULL);
84 * dma_pool_create - Creates a pool of consistent memory blocks, for dma.
85 * @name: name of pool, for diagnostics
86 * @dev: device that will be doing the DMA
87 * @size: size of the blocks in this pool.
88 * @align: alignment requirement for blocks; must be a power of two
89 * @allocation: returned blocks won't cross this boundary (or zero)
90 * Context: !in_interrupt()
92 * Returns a dma allocation pool with the requested characteristics, or
93 * null if one can't be created. Given one of these pools, dma_pool_alloc()
94 * may be used to allocate memory. Such memory will all have "consistent"
95 * DMA mappings, accessible by the device and its driver without using
96 * cache flushing primitives. The actual size of blocks allocated may be
97 * larger than requested because of alignment.
99 * If allocation is nonzero, objects returned from dma_pool_alloc() won't
100 * cross that size boundary. This is useful for devices which have
101 * addressing restrictions on individual DMA transfers, such as not crossing
102 * boundaries of 4KBytes.
104 struct dma_pool *dma_pool_create(const char *name, struct device *dev,
105 size_t size, size_t align, size_t allocation)
107 struct dma_pool *retval;
113 else if (size < align)
115 else if ((size % align) != 0) {
117 size &= ~(align - 1);
120 if (allocation == 0) {
121 if (PAGE_SIZE < size)
124 allocation = PAGE_SIZE;
125 /* FIXME: round up for less fragmentation */
126 } else if (allocation < size)
131 kmalloc_node(sizeof *retval, GFP_KERNEL, dev_to_node(dev))))
134 strlcpy(retval->name, name, sizeof retval->name);
138 INIT_LIST_HEAD(&retval->page_list);
139 spin_lock_init(&retval->lock);
141 retval->allocation = allocation;
142 retval->blocks_per_page = allocation / size;
143 init_waitqueue_head(&retval->waitq);
148 mutex_lock(&pools_lock);
149 if (list_empty(&dev->dma_pools))
150 ret = device_create_file(dev, &dev_attr_pools);
153 /* note: not currently insisting "name" be unique */
155 list_add(&retval->pools, &dev->dma_pools);
160 mutex_unlock(&pools_lock);
162 INIT_LIST_HEAD(&retval->pools);
166 EXPORT_SYMBOL(dma_pool_create);
168 static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags)
170 struct dma_page *page;
173 mapsize = pool->blocks_per_page;
174 mapsize = (mapsize + BITS_PER_LONG - 1) / BITS_PER_LONG;
175 mapsize *= sizeof(long);
177 page = kmalloc(mapsize + sizeof *page, mem_flags);
180 page->vaddr = dma_alloc_coherent(pool->dev,
182 &page->dma, mem_flags);
184 memset(page->bitmap, 0xff, mapsize); /* bit set == free */
185 #ifdef CONFIG_DEBUG_SLAB
186 memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
188 list_add(&page->page_list, &pool->page_list);
197 static inline int is_page_busy(int blocks, unsigned long *bitmap)
200 if (*bitmap++ != ~0UL)
202 blocks -= BITS_PER_LONG;
207 static void pool_free_page(struct dma_pool *pool, struct dma_page *page)
209 dma_addr_t dma = page->dma;
211 #ifdef CONFIG_DEBUG_SLAB
212 memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
214 dma_free_coherent(pool->dev, pool->allocation, page->vaddr, dma);
215 list_del(&page->page_list);
220 * dma_pool_destroy - destroys a pool of dma memory blocks.
221 * @pool: dma pool that will be destroyed
222 * Context: !in_interrupt()
224 * Caller guarantees that no more memory from the pool is in use,
225 * and that nothing will try to use the pool after this call.
227 void dma_pool_destroy(struct dma_pool *pool)
229 mutex_lock(&pools_lock);
230 list_del(&pool->pools);
231 if (pool->dev && list_empty(&pool->dev->dma_pools))
232 device_remove_file(pool->dev, &dev_attr_pools);
233 mutex_unlock(&pools_lock);
235 while (!list_empty(&pool->page_list)) {
236 struct dma_page *page;
237 page = list_entry(pool->page_list.next,
238 struct dma_page, page_list);
239 if (is_page_busy(pool->blocks_per_page, page->bitmap)) {
242 "dma_pool_destroy %s, %p busy\n",
243 pool->name, page->vaddr);
246 "dma_pool_destroy %s, %p busy\n",
247 pool->name, page->vaddr);
248 /* leak the still-in-use consistent memory */
249 list_del(&page->page_list);
252 pool_free_page(pool, page);
257 EXPORT_SYMBOL(dma_pool_destroy);
260 * dma_pool_alloc - get a block of consistent memory
261 * @pool: dma pool that will produce the block
262 * @mem_flags: GFP_* bitmask
263 * @handle: pointer to dma address of block
265 * This returns the kernel virtual address of a currently unused block,
266 * and reports its dma address through the handle.
267 * If such a memory block can't be allocated, null is returned.
269 void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags,
273 struct dma_page *page;
278 spin_lock_irqsave(&pool->lock, flags);
280 list_for_each_entry(page, &pool->page_list, page_list) {
282 /* only cachable accesses here ... */
284 i < pool->blocks_per_page; i += BITS_PER_LONG, map++) {
285 if (page->bitmap[map] == 0)
287 block = ffz(~page->bitmap[map]);
288 if ((i + block) < pool->blocks_per_page) {
289 clear_bit(block, &page->bitmap[map]);
290 offset = (BITS_PER_LONG * map) + block;
291 offset *= pool->size;
296 page = pool_alloc_page(pool, GFP_ATOMIC);
298 if (mem_flags & __GFP_WAIT) {
299 DECLARE_WAITQUEUE(wait, current);
301 __set_current_state(TASK_INTERRUPTIBLE);
302 __add_wait_queue(&pool->waitq, &wait);
303 spin_unlock_irqrestore(&pool->lock, flags);
305 schedule_timeout(POOL_TIMEOUT_JIFFIES);
307 spin_lock_irqsave(&pool->lock, flags);
308 __remove_wait_queue(&pool->waitq, &wait);
315 clear_bit(0, &page->bitmap[0]);
319 retval = offset + page->vaddr;
320 *handle = offset + page->dma;
321 #ifdef CONFIG_DEBUG_SLAB
322 memset(retval, POOL_POISON_ALLOCATED, pool->size);
325 spin_unlock_irqrestore(&pool->lock, flags);
328 EXPORT_SYMBOL(dma_pool_alloc);
330 static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma)
333 struct dma_page *page;
335 spin_lock_irqsave(&pool->lock, flags);
336 list_for_each_entry(page, &pool->page_list, page_list) {
339 if (dma < (page->dma + pool->allocation))
344 spin_unlock_irqrestore(&pool->lock, flags);
349 * dma_pool_free - put block back into dma pool
350 * @pool: the dma pool holding the block
351 * @vaddr: virtual address of block
352 * @dma: dma address of block
354 * Caller promises neither device nor driver will again touch this block
355 * unless it is first re-allocated.
357 void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma)
359 struct dma_page *page;
363 page = pool_find_page(pool, dma);
367 "dma_pool_free %s, %p/%lx (bad dma)\n",
368 pool->name, vaddr, (unsigned long)dma);
370 printk(KERN_ERR "dma_pool_free %s, %p/%lx (bad dma)\n",
371 pool->name, vaddr, (unsigned long)dma);
375 block = dma - page->dma;
377 map = block / BITS_PER_LONG;
378 block %= BITS_PER_LONG;
380 #ifdef CONFIG_DEBUG_SLAB
381 if (((dma - page->dma) + (void *)page->vaddr) != vaddr) {
384 "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
385 pool->name, vaddr, (unsigned long long)dma);
388 "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
389 pool->name, vaddr, (unsigned long long)dma);
392 if (page->bitmap[map] & (1UL << block)) {
395 "dma_pool_free %s, dma %Lx already free\n",
396 pool->name, (unsigned long long)dma);
399 "dma_pool_free %s, dma %Lx already free\n",
400 pool->name, (unsigned long long)dma);
403 memset(vaddr, POOL_POISON_FREED, pool->size);
406 spin_lock_irqsave(&pool->lock, flags);
408 set_bit(block, &page->bitmap[map]);
409 if (waitqueue_active(&pool->waitq))
410 wake_up_locked(&pool->waitq);
412 * Resist a temptation to do
413 * if (!is_page_busy(bpp, page->bitmap)) pool_free_page(pool, page);
414 * Better have a few empty pages hang around.
416 spin_unlock_irqrestore(&pool->lock, flags);
418 EXPORT_SYMBOL(dma_pool_free);
423 static void dmam_pool_release(struct device *dev, void *res)
425 struct dma_pool *pool = *(struct dma_pool **)res;
427 dma_pool_destroy(pool);
430 static int dmam_pool_match(struct device *dev, void *res, void *match_data)
432 return *(struct dma_pool **)res == match_data;
436 * dmam_pool_create - Managed dma_pool_create()
437 * @name: name of pool, for diagnostics
438 * @dev: device that will be doing the DMA
439 * @size: size of the blocks in this pool.
440 * @align: alignment requirement for blocks; must be a power of two
441 * @allocation: returned blocks won't cross this boundary (or zero)
443 * Managed dma_pool_create(). DMA pool created with this function is
444 * automatically destroyed on driver detach.
446 struct dma_pool *dmam_pool_create(const char *name, struct device *dev,
447 size_t size, size_t align, size_t allocation)
449 struct dma_pool **ptr, *pool;
451 ptr = devres_alloc(dmam_pool_release, sizeof(*ptr), GFP_KERNEL);
455 pool = *ptr = dma_pool_create(name, dev, size, align, allocation);
457 devres_add(dev, ptr);
463 EXPORT_SYMBOL(dmam_pool_create);
466 * dmam_pool_destroy - Managed dma_pool_destroy()
467 * @pool: dma pool that will be destroyed
469 * Managed dma_pool_destroy().
471 void dmam_pool_destroy(struct dma_pool *pool)
473 struct device *dev = pool->dev;
475 dma_pool_destroy(pool);
476 WARN_ON(devres_destroy(dev, dmam_pool_release, dmam_pool_match, pool));
478 EXPORT_SYMBOL(dmam_pool_destroy);