[net-next-2.6.git] / drivers / base / dmapool.c


#include <linux/device.h>
#include <linux/mm.h>
#include <asm/io.h>		/* Needed for i386 to build */
#include <asm/scatterlist.h>	/* Needed for i386 to build */
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/poison.h>
#include <linux/sched.h>

/*
 * Pool allocator ... wraps the dma_alloc_coherent page allocator, so
 * small blocks are easily used by drivers for bus mastering controllers.
 * This should probably be sharing the guts of the slab allocator.
 */

struct dma_pool {	/* the pool */
	struct list_head	page_list;
	spinlock_t		lock;
	size_t			blocks_per_page;
	size_t			size;
	struct device		*dev;
	size_t			allocation;
	char			name [32];
	wait_queue_head_t	waitq;
	struct list_head	pools;
};

struct dma_page {	/* cacheable header for 'allocation' bytes */
	struct list_head	page_list;
	void			*vaddr;
	dma_addr_t		dma;
	unsigned		in_use;
	unsigned long		bitmap [0];
};

#define	POOL_TIMEOUT_JIFFIES	((100 /* msec */ * HZ) / 1000)

static DEFINE_MUTEX (pools_lock);

static ssize_t
show_pools (struct device *dev, struct device_attribute *attr, char *buf)
{
	unsigned temp;
	unsigned size;
	char *next;
	struct dma_page *page;
	struct dma_pool *pool;

	next = buf;
	size = PAGE_SIZE;

	temp = scnprintf(next, size, "poolinfo - 0.1\n");
	size -= temp;
	next += temp;

	mutex_lock(&pools_lock);
	list_for_each_entry(pool, &dev->dma_pools, pools) {
		unsigned pages = 0;
		unsigned blocks = 0;

		list_for_each_entry(page, &pool->page_list, page_list) {
			pages++;
			blocks += page->in_use;
		}

		/* per-pool info, no real statistics yet */
		temp = scnprintf(next, size, "%-16s %4u %4Zu %4Zu %2u\n",
				pool->name,
				blocks, pages * pool->blocks_per_page,
				pool->size, pages);
		size -= temp;
		next += temp;
	}
	mutex_unlock(&pools_lock);

	return PAGE_SIZE - size;
}
static DEVICE_ATTR (pools, S_IRUGO, show_pools, NULL);

/**
 * dma_pool_create - Creates a pool of consistent memory blocks, for dma.
 * @name: name of pool, for diagnostics
 * @dev: device that will be doing the DMA
 * @size: size of the blocks in this pool.
 * @align: alignment requirement for blocks; must be a power of two
 * @allocation: returned blocks won't cross this boundary (or zero)
 * Context: !in_interrupt()
 *
 * Returns a dma allocation pool with the requested characteristics, or
 * null if one can't be created.  Given one of these pools, dma_pool_alloc()
 * may be used to allocate memory.  Such memory will all have "consistent"
 * DMA mappings, accessible by the device and its driver without using
 * cache flushing primitives.  The actual size of blocks allocated may be
 * larger than requested because of alignment.
 *
 * If allocation is nonzero, objects returned from dma_pool_alloc() won't
 * cross that size boundary.  This is useful for devices which have
 * addressing restrictions on individual DMA transfers, such as not crossing
 * boundaries of 4KBytes.
 */
struct dma_pool *
dma_pool_create (const char *name, struct device *dev,
	size_t size, size_t align, size_t allocation)
{
	struct dma_pool		*retval;

	if (align == 0)
		align = 1;
	if (size == 0)
		return NULL;
	else if (size < align)
		size = align;
	else if ((size % align) != 0) {
		size += align + 1;
		size &= ~(align - 1);
	}

	if (allocation == 0) {
		if (PAGE_SIZE < size)
			allocation = size;
		else
			allocation = PAGE_SIZE;
		// FIXME: round up for less fragmentation
	} else if (allocation < size)
		return NULL;

	if (!(retval = kmalloc_node (sizeof *retval, GFP_KERNEL, dev_to_node(dev))))
		return retval;

	strlcpy (retval->name, name, sizeof retval->name);

	retval->dev = dev;

	INIT_LIST_HEAD (&retval->page_list);
	spin_lock_init (&retval->lock);
	retval->size = size;
	retval->allocation = allocation;
	retval->blocks_per_page = allocation / size;
	init_waitqueue_head (&retval->waitq);

	if (dev) {
		int ret;

		mutex_lock(&pools_lock);
		if (list_empty (&dev->dma_pools))
			ret = device_create_file (dev, &dev_attr_pools);
		else
			ret = 0;
		/* note:  not currently insisting "name" be unique */
		if (!ret)
			list_add (&retval->pools, &dev->dma_pools);
		else {
			kfree(retval);
			retval = NULL;
		}
		mutex_unlock(&pools_lock);
	} else
		INIT_LIST_HEAD (&retval->pools);

	return retval;
}


static struct dma_page *
pool_alloc_page (struct dma_pool *pool, gfp_t mem_flags)
{
	struct dma_page	*page;
	int		mapsize;

	mapsize = pool->blocks_per_page;
	mapsize = (mapsize + BITS_PER_LONG - 1) / BITS_PER_LONG;
	mapsize *= sizeof (long);

	page = kmalloc(mapsize + sizeof *page, mem_flags);
	if (!page)
		return NULL;
	page->vaddr = dma_alloc_coherent (pool->dev,
					    pool->allocation,
					    &page->dma,
					    mem_flags);
	if (page->vaddr) {
		memset (page->bitmap, 0xff, mapsize);	// bit set == free
#ifdef	CONFIG_DEBUG_SLAB
		memset (page->vaddr, POOL_POISON_FREED, pool->allocation);
#endif
		list_add (&page->page_list, &pool->page_list);
		page->in_use = 0;
	} else {
		kfree (page);
		page = NULL;
	}
	return page;
}


static inline int
is_page_busy (int blocks, unsigned long *bitmap)
{
	while (blocks > 0) {
		if (*bitmap++ != ~0UL)
			return 1;
		blocks -= BITS_PER_LONG;
	}
	return 0;
}

static void
pool_free_page (struct dma_pool *pool, struct dma_page *page)
{
	dma_addr_t	dma = page->dma;

#ifdef	CONFIG_DEBUG_SLAB
	memset (page->vaddr, POOL_POISON_FREED, pool->allocation);
#endif
	dma_free_coherent (pool->dev, pool->allocation, page->vaddr, dma);
	list_del (&page->page_list);
	kfree (page);
}


/**
 * dma_pool_destroy - destroys a pool of dma memory blocks.
 * @pool: dma pool that will be destroyed
 * Context: !in_interrupt()
 *
 * Caller guarantees that no more memory from the pool is in use,
 * and that nothing will try to use the pool after this call.
 */
void
dma_pool_destroy (struct dma_pool *pool)
{
	mutex_lock(&pools_lock);
	list_del (&pool->pools);
	if (pool->dev && list_empty (&pool->dev->dma_pools))
		device_remove_file (pool->dev, &dev_attr_pools);
	mutex_unlock(&pools_lock);

	while (!list_empty (&pool->page_list)) {
		struct dma_page		*page;
		page = list_entry (pool->page_list.next,
				struct dma_page, page_list);
		if (is_page_busy (pool->blocks_per_page, page->bitmap)) {
			if (pool->dev)
				dev_err(pool->dev, "dma_pool_destroy %s, %p busy\n",
					pool->name, page->vaddr);
			else
				printk (KERN_ERR "dma_pool_destroy %s, %p busy\n",
					pool->name, page->vaddr);
			/* leak the still-in-use consistent memory */
			list_del (&page->page_list);
			kfree (page);
		} else
			pool_free_page (pool, page);
	}

	kfree (pool);
}


/**
 * dma_pool_alloc - get a block of consistent memory
 * @pool: dma pool that will produce the block
 * @mem_flags: GFP_* bitmask
 * @handle: pointer to dma address of block
 *
 * This returns the kernel virtual address of a currently unused block,
 * and reports its dma address through the handle.
 * If such a memory block can't be allocated, null is returned.
 */
void *
dma_pool_alloc (struct dma_pool *pool, gfp_t mem_flags, dma_addr_t *handle)
{
	unsigned long		flags;
	struct dma_page		*page;
	int			map, block;
	size_t			offset;
	void			*retval;

restart:
	spin_lock_irqsave (&pool->lock, flags);
	list_for_each_entry(page, &pool->page_list, page_list) {
		int		i;
		/* only cachable accesses here ... */
		for (map = 0, i = 0;
				i < pool->blocks_per_page;
				i += BITS_PER_LONG, map++) {
			if (page->bitmap [map] == 0)
				continue;
			block = ffz (~ page->bitmap [map]);
			if ((i + block) < pool->blocks_per_page) {
				clear_bit (block, &page->bitmap [map]);
				offset = (BITS_PER_LONG * map) + block;
				offset *= pool->size;
				goto ready;
			}
		}
	}
	if (!(page = pool_alloc_page (pool, GFP_ATOMIC))) {
		if (mem_flags & __GFP_WAIT) {
			DECLARE_WAITQUEUE (wait, current);

			current->state = TASK_INTERRUPTIBLE;
			add_wait_queue (&pool->waitq, &wait);
			spin_unlock_irqrestore (&pool->lock, flags);

			schedule_timeout (POOL_TIMEOUT_JIFFIES);

			remove_wait_queue (&pool->waitq, &wait);
			goto restart;
		}
		retval = NULL;
		goto done;
	}

	clear_bit (0, &page->bitmap [0]);
	offset = 0;
ready:
	page->in_use++;
	retval = offset + page->vaddr;
	*handle = offset + page->dma;
#ifdef	CONFIG_DEBUG_SLAB
	memset (retval, POOL_POISON_ALLOCATED, pool->size);
#endif
done:
	spin_unlock_irqrestore (&pool->lock, flags);
	return retval;
}


static struct dma_page *
pool_find_page (struct dma_pool *pool, dma_addr_t dma)
{
	unsigned long		flags;
	struct dma_page		*page;

	spin_lock_irqsave (&pool->lock, flags);
	list_for_each_entry(page, &pool->page_list, page_list) {
		if (dma < page->dma)
			continue;
		if (dma < (page->dma + pool->allocation))
			goto done;
	}
	page = NULL;
done:
	spin_unlock_irqrestore (&pool->lock, flags);
	return page;
}


/**
 * dma_pool_free - put block back into dma pool
 * @pool: the dma pool holding the block
 * @vaddr: virtual address of block
 * @dma: dma address of block
 *
 * Caller promises neither device nor driver will again touch this block
 * unless it is first re-allocated.
 */
void
dma_pool_free (struct dma_pool *pool, void *vaddr, dma_addr_t dma)
{
	struct dma_page		*page;
	unsigned long		flags;
	int			map, block;

	if ((page = pool_find_page (pool, dma)) == 0) {
		if (pool->dev)
			dev_err(pool->dev, "dma_pool_free %s, %p/%lx (bad dma)\n",
				pool->name, vaddr, (unsigned long) dma);
		else
			printk (KERN_ERR "dma_pool_free %s, %p/%lx (bad dma)\n",
				pool->name, vaddr, (unsigned long) dma);
		return;
	}

	block = dma - page->dma;
	block /= pool->size;
	map = block / BITS_PER_LONG;
	block %= BITS_PER_LONG;

#ifdef	CONFIG_DEBUG_SLAB
	if (((dma - page->dma) + (void *)page->vaddr) != vaddr) {
		if (pool->dev)
			dev_err(pool->dev, "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
				pool->name, vaddr, (unsigned long long) dma);
		else
			printk (KERN_ERR "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
				pool->name, vaddr, (unsigned long long) dma);
		return;
	}
	if (page->bitmap [map] & (1UL << block)) {
		if (pool->dev)
			dev_err(pool->dev, "dma_pool_free %s, dma %Lx already free\n",
				pool->name, (unsigned long long)dma);
		else
			printk (KERN_ERR "dma_pool_free %s, dma %Lx already free\n",
				pool->name, (unsigned long long)dma);
		return;
	}
	memset (vaddr, POOL_POISON_FREED, pool->size);
#endif

	spin_lock_irqsave (&pool->lock, flags);
	page->in_use--;
	set_bit (block, &page->bitmap [map]);
	if (waitqueue_active (&pool->waitq))
		wake_up (&pool->waitq);
	/*
	 * Resist a temptation to do
	 *    if (!is_page_busy(bpp, page->bitmap)) pool_free_page(pool, page);
	 * Better have a few empty pages hang around.
	 */
	spin_unlock_irqrestore (&pool->lock, flags);
}

/*
 * Managed DMA pool
 */
static void dmam_pool_release(struct device *dev, void *res)
{
	struct dma_pool *pool = *(struct dma_pool **)res;

	dma_pool_destroy(pool);
}

static int dmam_pool_match(struct device *dev, void *res, void *match_data)
{
	return *(struct dma_pool **)res == match_data;
}

/**
 * dmam_pool_create - Managed dma_pool_create()
 * @name: name of pool, for diagnostics
 * @dev: device that will be doing the DMA
 * @size: size of the blocks in this pool.
 * @align: alignment requirement for blocks; must be a power of two
 * @allocation: returned blocks won't cross this boundary (or zero)
 *
 * Managed dma_pool_create().  DMA pool created with this function is
 * automatically destroyed on driver detach.
 */
struct dma_pool *dmam_pool_create(const char *name, struct device *dev,
				  size_t size, size_t align, size_t allocation)
{
	struct dma_pool **ptr, *pool;

	ptr = devres_alloc(dmam_pool_release, sizeof(*ptr), GFP_KERNEL);
	if (!ptr)
		return NULL;

	pool = *ptr = dma_pool_create(name, dev, size, align, allocation);
	if (pool)
		devres_add(dev, ptr);
	else
		devres_free(ptr);

	return pool;
}

/**
 * dmam_pool_destroy - Managed dma_pool_destroy()
 * @pool: dma pool that will be destroyed
 *
 * Managed dma_pool_destroy().
 */
void dmam_pool_destroy(struct dma_pool *pool)
{
	struct device *dev = pool->dev;

	dma_pool_destroy(pool);
	WARN_ON(devres_destroy(dev, dmam_pool_release, dmam_pool_match, pool));
}

EXPORT_SYMBOL (dma_pool_create);
EXPORT_SYMBOL (dma_pool_destroy);
EXPORT_SYMBOL (dma_pool_alloc);
EXPORT_SYMBOL (dma_pool_free);
EXPORT_SYMBOL (dmam_pool_create);
EXPORT_SYMBOL (dmam_pool_destroy);
Commit	Line	Data
1da177e4 LT	1
	2	#include <linux/device.h>
	3	#include <linux/mm.h>
	4	#include <asm/io.h> /* Needed for i386 to build */
	5	#include <asm/scatterlist.h> /* Needed for i386 to build */
	6	#include <linux/dma-mapping.h>
	7	#include <linux/dmapool.h>
	8	#include <linux/slab.h>
	9	#include <linux/module.h>
c9cf5528	10	#include <linux/poison.h>
e8edc6e0	11	#include <linux/sched.h>
1da177e4 LT	12
	13	/*
	14	* Pool allocator ... wraps the dma_alloc_coherent page allocator, so
	15	* small blocks are easily used by drivers for bus mastering controllers.
	16	* This should probably be sharing the guts of the slab allocator.
	17	*/
	18
	19	struct dma_pool { /* the pool */
	20	struct list_head page_list;
	21	spinlock_t lock;
	22	size_t blocks_per_page;
	23	size_t size;
	24	struct device *dev;
	25	size_t allocation;
	26	char name [32];
	27	wait_queue_head_t waitq;
	28	struct list_head pools;
	29	};
	30
	31	struct dma_page { /* cacheable header for 'allocation' bytes */
	32	struct list_head page_list;
	33	void *vaddr;
	34	dma_addr_t dma;
	35	unsigned in_use;
	36	unsigned long bitmap [0];
	37	};
	38
	39	#define POOL_TIMEOUT_JIFFIES ((100 /* msec / HZ) / 1000)
1da177e4	40
b2366d68	41	static DEFINE_MUTEX (pools_lock);
1da177e4 LT	42
1da177e4 LT	43	static ssize_t
74880c06	44	show_pools (struct device dev, struct device_attribute attr, char *buf)
1da177e4 LT	45	{
	46	unsigned temp;
	47	unsigned size;
	48	char *next;
	49	struct dma_page *page;
	50	struct dma_pool *pool;
	51
	52	next = buf;
	53	size = PAGE_SIZE;
	54
	55	temp = scnprintf(next, size, "poolinfo - 0.1\n");
	56	size -= temp;
	57	next += temp;
	58
b2366d68	59	mutex_lock(&pools_lock);
1da177e4 LT	60	list_for_each_entry(pool, &dev->dma_pools, pools) {
	61	unsigned pages = 0;
	62	unsigned blocks = 0;
	63
	64	list_for_each_entry(page, &pool->page_list, page_list) {
	65	pages++;
	66	blocks += page->in_use;
	67	}
	68
	69	/* per-pool info, no real statistics yet */
	70	temp = scnprintf(next, size, "%-16s %4u %4Zu %4Zu %2u\n",
	71	pool->name,
	72	blocks, pages * pool->blocks_per_page,
	73	pool->size, pages);
	74	size -= temp;
	75	next += temp;
	76	}
b2366d68	77	mutex_unlock(&pools_lock);
1da177e4 LT	78
	79	return PAGE_SIZE - size;
	80	}
	81	static DEVICE_ATTR (pools, S_IRUGO, show_pools, NULL);
	82
	83	/**
	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()
	91	*
	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.
	98	*
	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.
	103	*/
	104	struct dma_pool *
	105	dma_pool_create (const char name, struct device dev,
	106	size_t size, size_t align, size_t allocation)
	107	{
	108	struct dma_pool *retval;
	109
	110	if (align == 0)
	111	align = 1;
	112	if (size == 0)
	113	return NULL;
	114	else if (size < align)
	115	size = align;
	116	else if ((size % align) != 0) {
	117	size += align + 1;
	118	size &= ~(align - 1);
	119	}
	120
	121	if (allocation == 0) {
	122	if (PAGE_SIZE < size)
	123	allocation = size;
	124	else
	125	allocation = PAGE_SIZE;
	126	// FIXME: round up for less fragmentation
	127	} else if (allocation < size)
	128	return NULL;
	129
2618c60b	130	if (!(retval = kmalloc_node (sizeof *retval, GFP_KERNEL, dev_to_node(dev))))
1da177e4 LT	131	return retval;
	132
	133	strlcpy (retval->name, name, sizeof retval->name);
	134
	135	retval->dev = dev;
	136
	137	INIT_LIST_HEAD (&retval->page_list);
	138	spin_lock_init (&retval->lock);
	139	retval->size = size;
	140	retval->allocation = allocation;
	141	retval->blocks_per_page = allocation / size;
	142	init_waitqueue_head (&retval->waitq);
	143
	144	if (dev) {
141ecc53 CH	145	int ret;
141ecc53 CH	146
b2366d68	147	mutex_lock(&pools_lock);
1da177e4	148	if (list_empty (&dev->dma_pools))
141ecc53 CH	149	ret = device_create_file (dev, &dev_attr_pools);
	150	else
	151	ret = 0;
1da177e4	152	/* note: not currently insisting "name" be unique */
141ecc53 CH	153	if (!ret)
	154	list_add (&retval->pools, &dev->dma_pools);
	155	else {
	156	kfree(retval);
	157	retval = NULL;
	158	}
b2366d68	159	mutex_unlock(&pools_lock);
1da177e4 LT	160	} else
	161	INIT_LIST_HEAD (&retval->pools);
	162
	163	return retval;
	164	}
	165
	166
	167	static struct dma_page *
dd0fc66f	168	pool_alloc_page (struct dma_pool *pool, gfp_t mem_flags)
1da177e4 LT	169	{
	170	struct dma_page *page;
	171	int mapsize;
	172
	173	mapsize = pool->blocks_per_page;
	174	mapsize = (mapsize + BITS_PER_LONG - 1) / BITS_PER_LONG;
	175	mapsize *= sizeof (long);
	176
5cbded58	177	page = kmalloc(mapsize + sizeof *page, mem_flags);
1da177e4 LT	178	if (!page)
	179	return NULL;
	180	page->vaddr = dma_alloc_coherent (pool->dev,
	181	pool->allocation,
	182	&page->dma,
	183	mem_flags);
	184	if (page->vaddr) {
	185	memset (page->bitmap, 0xff, mapsize); // bit set == free
	186	#ifdef CONFIG_DEBUG_SLAB
	187	memset (page->vaddr, POOL_POISON_FREED, pool->allocation);
	188	#endif
	189	list_add (&page->page_list, &pool->page_list);
	190	page->in_use = 0;
	191	} else {
	192	kfree (page);
	193	page = NULL;
	194	}
	195	return page;
	196	}
	197
	198
	199	static inline int
	200	is_page_busy (int blocks, unsigned long *bitmap)
	201	{
	202	while (blocks > 0) {
	203	if (*bitmap++ != ~0UL)
	204	return 1;
	205	blocks -= BITS_PER_LONG;
	206	}
	207	return 0;
	208	}
	209
	210	static void
	211	pool_free_page (struct dma_pool pool, struct dma_page page)
	212	{
	213	dma_addr_t dma = page->dma;
	214
	215	#ifdef CONFIG_DEBUG_SLAB
	216	memset (page->vaddr, POOL_POISON_FREED, pool->allocation);
	217	#endif
	218	dma_free_coherent (pool->dev, pool->allocation, page->vaddr, dma);
	219	list_del (&page->page_list);
	220	kfree (page);
	221	}
	222
	223
	224	/**
	225	* dma_pool_destroy - destroys a pool of dma memory blocks.
	226	* @pool: dma pool that will be destroyed
	227	* Context: !in_interrupt()
	228	*
	229	* Caller guarantees that no more memory from the pool is in use,
	230	* and that nothing will try to use the pool after this call.
	231	*/
	232	void
	233	dma_pool_destroy (struct dma_pool *pool)
	234	{
b2366d68	235	mutex_lock(&pools_lock);
1da177e4 LT	236	list_del (&pool->pools);
	237	if (pool->dev && list_empty (&pool->dev->dma_pools))
	238	device_remove_file (pool->dev, &dev_attr_pools);
b2366d68	239	mutex_unlock(&pools_lock);
1da177e4 LT	240
	241	while (!list_empty (&pool->page_list)) {
	242	struct dma_page *page;
	243	page = list_entry (pool->page_list.next,
	244	struct dma_page, page_list);
	245	if (is_page_busy (pool->blocks_per_page, page->bitmap)) {
	246	if (pool->dev)
	247	dev_err(pool->dev, "dma_pool_destroy %s, %p busy\n",
	248	pool->name, page->vaddr);
	249	else
	250	printk (KERN_ERR "dma_pool_destroy %s, %p busy\n",
	251	pool->name, page->vaddr);
	252	/* leak the still-in-use consistent memory */
	253	list_del (&page->page_list);
	254	kfree (page);
	255	} else
	256	pool_free_page (pool, page);
	257	}
	258
	259	kfree (pool);
	260	}
	261
	262
	263	/**
	264	* dma_pool_alloc - get a block of consistent memory
	265	* @pool: dma pool that will produce the block
	266	* @mem_flags: GFP_* bitmask
	267	* @handle: pointer to dma address of block
	268	*
	269	* This returns the kernel virtual address of a currently unused block,
	270	* and reports its dma address through the handle.
	271	* If such a memory block can't be allocated, null is returned.
	272	*/
	273	void *
dd0fc66f	274	dma_pool_alloc (struct dma_pool pool, gfp_t mem_flags, dma_addr_t handle)
1da177e4 LT	275	{
	276	unsigned long flags;
	277	struct dma_page *page;
	278	int map, block;
	279	size_t offset;
	280	void *retval;
	281
	282	restart:
	283	spin_lock_irqsave (&pool->lock, flags);
	284	list_for_each_entry(page, &pool->page_list, page_list) {
	285	int i;
	286	/* only cachable accesses here ... */
	287	for (map = 0, i = 0;
	288	i < pool->blocks_per_page;
	289	i += BITS_PER_LONG, map++) {
	290	if (page->bitmap [map] == 0)
	291	continue;
	292	block = ffz (~ page->bitmap [map]);
	293	if ((i + block) < pool->blocks_per_page) {
	294	clear_bit (block, &page->bitmap [map]);
	295	offset = (BITS_PER_LONG * map) + block;
	296	offset *= pool->size;
	297	goto ready;
	298	}
	299	}
	300	}
54e6ecb2	301	if (!(page = pool_alloc_page (pool, GFP_ATOMIC))) {
1da177e4 LT	302	if (mem_flags & __GFP_WAIT) {
	303	DECLARE_WAITQUEUE (wait, current);
	304
	305	current->state = TASK_INTERRUPTIBLE;
	306	add_wait_queue (&pool->waitq, &wait);
	307	spin_unlock_irqrestore (&pool->lock, flags);
	308
	309	schedule_timeout (POOL_TIMEOUT_JIFFIES);
	310
	311	remove_wait_queue (&pool->waitq, &wait);
	312	goto restart;
	313	}
	314	retval = NULL;
	315	goto done;
	316	}
	317
	318	clear_bit (0, &page->bitmap [0]);
	319	offset = 0;
	320	ready:
	321	page->in_use++;
	322	retval = offset + page->vaddr;
	323	*handle = offset + page->dma;
	324	#ifdef CONFIG_DEBUG_SLAB
	325	memset (retval, POOL_POISON_ALLOCATED, pool->size);
	326	#endif
	327	done:
	328	spin_unlock_irqrestore (&pool->lock, flags);
	329	return retval;
	330	}
	331
	332
	333	static struct dma_page *
	334	pool_find_page (struct dma_pool *pool, dma_addr_t dma)
	335	{
	336	unsigned long flags;
	337	struct dma_page *page;
	338
	339	spin_lock_irqsave (&pool->lock, flags);
	340	list_for_each_entry(page, &pool->page_list, page_list) {
	341	if (dma < page->dma)
	342	continue;
	343	if (dma < (page->dma + pool->allocation))
	344	goto done;
	345	}
	346	page = NULL;
	347	done:
	348	spin_unlock_irqrestore (&pool->lock, flags);
	349	return page;
	350	}
	351
	352
	353	/**
	354	* dma_pool_free - put block back into dma pool
	355	* @pool: the dma pool holding the block
	356	* @vaddr: virtual address of block
	357	* @dma: dma address of block
	358	*
	359	* Caller promises neither device nor driver will again touch this block
	360	* unless it is first re-allocated.
	361	*/
	362	void
	363	dma_pool_free (struct dma_pool pool, void vaddr, dma_addr_t dma)
	364	{
	365	struct dma_page *page;
366	unsigned long flags;
367	int map, block;
368
369	if ((page = pool_find_page (pool, dma)) == 0) {
370	if (pool->dev)
371	dev_err(pool->dev, "dma_pool_free %s, %p/%lx (bad dma)\n",
372	pool->name, vaddr, (unsigned long) dma);
373	else
374	printk (KERN_ERR "dma_pool_free %s, %p/%lx (bad dma)\n",
375	pool->name, vaddr, (unsigned long) dma);
376	return;
377	}
378
379	block = dma - page->dma;
380	block /= pool->size;
381	map = block / BITS_PER_LONG;
382	block %= BITS_PER_LONG;
383
384	#ifdef CONFIG_DEBUG_SLAB
385	if (((dma - page->dma) + (void *)page->vaddr) != vaddr) {
386	if (pool->dev)
387	dev_err(pool->dev, "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
388	pool->name, vaddr, (unsigned long long) dma);
389	else
390	printk (KERN_ERR "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
391	pool->name, vaddr, (unsigned long long) dma);
392	return;
393	}
394	if (page->bitmap [map] & (1UL << block)) {
395	if (pool->dev)
396	dev_err(pool->dev, "dma_pool_free %s, dma %Lx already free\n",
397	pool->name, (unsigned long long)dma);
398	else
399	printk (KERN_ERR "dma_pool_free %s, dma %Lx already free\n",
400	pool->name, (unsigned long long)dma);
401	return;
402	}
403	memset (vaddr, POOL_POISON_FREED, pool->size);
404	#endif
405
406	spin_lock_irqsave (&pool->lock, flags);
407	page->in_use--;
408	set_bit (block, &page->bitmap [map]);
409	if (waitqueue_active (&pool->waitq))
410	wake_up (&pool->waitq);
411	/*
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.
415	*/
416	spin_unlock_irqrestore (&pool->lock, flags);
417	}
418
9ac7849e TH	419	/*
	420	* Managed DMA pool
	421	*/
	422	static void dmam_pool_release(struct device dev, void res)
	423	{
	424	struct dma_pool pool = (struct dma_pool **)res;
	425
	426	dma_pool_destroy(pool);
	427	}
	428
	429	static int dmam_pool_match(struct device dev, void res, void *match_data)
	430	{
	431	return (struct dma_pool *)res == match_data;
	432	}
	433
	434	/**
	435	* dmam_pool_create - Managed dma_pool_create()
	436	* @name: name of pool, for diagnostics
	437	* @dev: device that will be doing the DMA
	438	* @size: size of the blocks in this pool.
	439	* @align: alignment requirement for blocks; must be a power of two
	440	* @allocation: returned blocks won't cross this boundary (or zero)
	441	*
	442	* Managed dma_pool_create(). DMA pool created with this function is
	443	* automatically destroyed on driver detach.
	444	*/
	445	struct dma_pool dmam_pool_create(const char name, struct device *dev,
	446	size_t size, size_t align, size_t allocation)
	447	{
	448	struct dma_pool *ptr, pool;
	449
	450	ptr = devres_alloc(dmam_pool_release, sizeof(*ptr), GFP_KERNEL);
	451	if (!ptr)
	452	return NULL;
	453
	454	pool = *ptr = dma_pool_create(name, dev, size, align, allocation);
	455	if (pool)
	456	devres_add(dev, ptr);
	457	else
	458	devres_free(ptr);
	459
	460	return pool;
	461	}
	462
	463	/**
	464	* dmam_pool_destroy - Managed dma_pool_destroy()
	465	* @pool: dma pool that will be destroyed
	466	*
	467	* Managed dma_pool_destroy().
	468	*/
	469	void dmam_pool_destroy(struct dma_pool *pool)
	470	{
	471	struct device *dev = pool->dev;
	472
	473	dma_pool_destroy(pool);
	474	WARN_ON(devres_destroy(dev, dmam_pool_release, dmam_pool_match, pool));
	475	}
1da177e4 LT	476
	477	EXPORT_SYMBOL (dma_pool_create);
	478	EXPORT_SYMBOL (dma_pool_destroy);
	479	EXPORT_SYMBOL (dma_pool_alloc);
	480	EXPORT_SYMBOL (dma_pool_free);
9ac7849e TH	481	EXPORT_SYMBOL (dmam_pool_create);
9ac7849e TH	482	EXPORT_SYMBOL (dmam_pool_destroy);