[linux-2.6-block.git] / lib / iommu-common.c

/*
 * IOMMU mmap management and range allocation functions.
 * Based almost entirely upon the powerpc iommu allocator.
 */

#include <linux/export.h>
#include <linux/bitmap.h>
#include <linux/bug.h>
#include <linux/iommu-helper.h>
#include <linux/iommu-common.h>
#include <linux/dma-mapping.h>
#include <linux/hash.h>

#ifndef	DMA_ERROR_CODE
#define	DMA_ERROR_CODE (~(dma_addr_t)0x0)
#endif

static unsigned long iommu_large_alloc = 15;

static	DEFINE_PER_CPU(unsigned int, iommu_hash_common);

static inline bool need_flush(struct iommu_map_table *iommu)
{
	return (iommu->lazy_flush != NULL &&
		(iommu->flags & IOMMU_NEED_FLUSH) != 0);
}

static inline void set_flush(struct iommu_map_table *iommu)
{
	iommu->flags |= IOMMU_NEED_FLUSH;
}

static inline void clear_flush(struct iommu_map_table *iommu)
{
	iommu->flags &= ~IOMMU_NEED_FLUSH;
}

static void setup_iommu_pool_hash(void)
{
	unsigned int i;
	static bool do_once;

	if (do_once)
		return;
	do_once = true;
	for_each_possible_cpu(i)
		per_cpu(iommu_hash_common, i) = hash_32(i, IOMMU_POOL_HASHBITS);
}

/*
 * Initialize iommu_pool entries for the iommu_map_table. `num_entries'
 * is the number of table entries. If `large_pool' is set to true,
 * the top 1/4 of the table will be set aside for pool allocations
 * of more than iommu_large_alloc pages.
 */
void iommu_tbl_pool_init(struct iommu_map_table *iommu,
			 unsigned long num_entries,
			 u32 table_shift,
			 void (*lazy_flush)(struct iommu_map_table *),
			 bool large_pool, u32 npools,
			 bool skip_span_boundary_check)
{
	unsigned int start, i;
	struct iommu_pool *p = &(iommu->large_pool);

	setup_iommu_pool_hash();
	if (npools == 0)
		iommu->nr_pools = IOMMU_NR_POOLS;
	else
		iommu->nr_pools = npools;
	BUG_ON(npools > IOMMU_NR_POOLS);

	iommu->table_shift = table_shift;
	iommu->lazy_flush = lazy_flush;
	start = 0;
	if (skip_span_boundary_check)
		iommu->flags |= IOMMU_NO_SPAN_BOUND;
	if (large_pool)
		iommu->flags |= IOMMU_HAS_LARGE_POOL;

	if (!large_pool)
		iommu->poolsize = num_entries/iommu->nr_pools;
	else
		iommu->poolsize = (num_entries * 3 / 4)/iommu->nr_pools;
	for (i = 0; i < iommu->nr_pools; i++) {
		spin_lock_init(&(iommu->pools[i].lock));
		iommu->pools[i].start = start;
		iommu->pools[i].hint = start;
		start += iommu->poolsize; /* start for next pool */
		iommu->pools[i].end = start - 1;
	}
	if (!large_pool)
		return;
	/* initialize large_pool */
	spin_lock_init(&(p->lock));
	p->start = start;
	p->hint = p->start;
	p->end = num_entries;
}
EXPORT_SYMBOL(iommu_tbl_pool_init);

unsigned long iommu_tbl_range_alloc(struct device *dev,
				struct iommu_map_table *iommu,
				unsigned long npages,
				unsigned long *handle,
				unsigned long mask,
				unsigned int align_order)
{
	unsigned int pool_hash = __this_cpu_read(iommu_hash_common);
	unsigned long n, end, start, limit, boundary_size;
	struct iommu_pool *pool;
	int pass = 0;
	unsigned int pool_nr;
	unsigned int npools = iommu->nr_pools;
	unsigned long flags;
	bool large_pool = ((iommu->flags & IOMMU_HAS_LARGE_POOL) != 0);
	bool largealloc = (large_pool && npages > iommu_large_alloc);
	unsigned long shift;
	unsigned long align_mask = 0;

	if (align_order > 0)
		align_mask = ~0ul >> (BITS_PER_LONG - align_order);

	/* Sanity check */
	if (unlikely(npages == 0)) {
		WARN_ON_ONCE(1);
		return DMA_ERROR_CODE;
	}

	if (largealloc) {
		pool = &(iommu->large_pool);
		pool_nr = 0; /* to keep compiler happy */
	} else {
		/* pick out pool_nr */
		pool_nr =  pool_hash & (npools - 1);
		pool = &(iommu->pools[pool_nr]);
	}
	spin_lock_irqsave(&pool->lock, flags);

 again:
	if (pass == 0 && handle && *handle &&
	    (*handle >= pool->start) && (*handle < pool->end))
		start = *handle;
	else
		start = pool->hint;

	limit = pool->end;

	/* The case below can happen if we have a small segment appended
	 * to a large, or when the previous alloc was at the very end of
	 * the available space. If so, go back to the beginning. If a
	 * flush is needed, it will get done based on the return value
	 * from iommu_area_alloc() below.
	 */
	if (start >= limit)
		start = pool->start;
	shift = iommu->table_map_base >> iommu->table_shift;
	if (limit + shift > mask) {
		limit = mask - shift + 1;
		/* If we're constrained on address range, first try
		 * at the masked hint to avoid O(n) search complexity,
		 * but on second pass, start at 0 in pool 0.
		 */
		if ((start & mask) >= limit || pass > 0) {
			spin_unlock(&(pool->lock));
			pool = &(iommu->pools[0]);
			spin_lock(&(pool->lock));
			start = pool->start;
		} else {
			start &= mask;
		}
	}

	if (dev)
		boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
				      1 << iommu->table_shift);
	else
		boundary_size = ALIGN(1ULL << 32, 1 << iommu->table_shift);

	boundary_size = boundary_size >> iommu->table_shift;
	/*
	 * if the skip_span_boundary_check had been set during init, we set
	 * things up so that iommu_is_span_boundary() merely checks if the
	 * (index + npages) < num_tsb_entries
	 */
	if ((iommu->flags & IOMMU_NO_SPAN_BOUND) != 0) {
		shift = 0;
		boundary_size = iommu->poolsize * iommu->nr_pools;
	}
	n = iommu_area_alloc(iommu->map, limit, start, npages, shift,
			     boundary_size, align_mask);
	if (n == -1) {
		if (likely(pass == 0)) {
			/* First failure, rescan from the beginning.  */
			pool->hint = pool->start;
			set_flush(iommu);
			pass++;
			goto again;
		} else if (!largealloc && pass <= iommu->nr_pools) {
			spin_unlock(&(pool->lock));
			pool_nr = (pool_nr + 1) & (iommu->nr_pools - 1);
			pool = &(iommu->pools[pool_nr]);
			spin_lock(&(pool->lock));
			pool->hint = pool->start;
			set_flush(iommu);
			pass++;
			goto again;
		} else {
			/* give up */
			n = DMA_ERROR_CODE;
			goto bail;
		}
	}
	if (n < pool->hint || need_flush(iommu)) {
		clear_flush(iommu);
		iommu->lazy_flush(iommu);
	}

	end = n + npages;
	pool->hint = end;

	/* Update handle for SG allocations */
	if (handle)
		*handle = end;
bail:
	spin_unlock_irqrestore(&(pool->lock), flags);

	return n;
}
EXPORT_SYMBOL(iommu_tbl_range_alloc);

static struct iommu_pool *get_pool(struct iommu_map_table *tbl,
				   unsigned long entry)
{
	struct iommu_pool *p;
	unsigned long largepool_start = tbl->large_pool.start;
	bool large_pool = ((tbl->flags & IOMMU_HAS_LARGE_POOL) != 0);

	/* The large pool is the last pool at the top of the table */
	if (large_pool && entry >= largepool_start) {
		p = &tbl->large_pool;
	} else {
		unsigned int pool_nr = entry / tbl->poolsize;

		BUG_ON(pool_nr >= tbl->nr_pools);
		p = &tbl->pools[pool_nr];
	}
	return p;
}

/* Caller supplies the index of the entry into the iommu map table
 * itself when the mapping from dma_addr to the entry is not the
 * default addr->entry mapping below.
 */
void iommu_tbl_range_free(struct iommu_map_table *iommu, u64 dma_addr,
			  unsigned long npages, unsigned long entry)
{
	struct iommu_pool *pool;
	unsigned long flags;
	unsigned long shift = iommu->table_shift;

	if (entry == DMA_ERROR_CODE) /* use default addr->entry mapping */
		entry = (dma_addr - iommu->table_map_base) >> shift;
	pool = get_pool(iommu, entry);

	spin_lock_irqsave(&(pool->lock), flags);
	bitmap_clear(iommu->map, entry, npages);
	spin_unlock_irqrestore(&(pool->lock), flags);
}
EXPORT_SYMBOL(iommu_tbl_range_free);
Commit	Line	Data
ff7d37a5 SV	1	/*
	2	* IOMMU mmap management and range allocation functions.
	3	* Based almost entirely upon the powerpc iommu allocator.
	4	*/
	5
	6	#include <linux/export.h>
	7	#include <linux/bitmap.h>
	8	#include <linux/bug.h>
	9	#include <linux/iommu-helper.h>
	10	#include <linux/iommu-common.h>
	11	#include <linux/dma-mapping.h>
	12	#include <linux/hash.h>
	13
2f0c0fdc SV	14	#ifndef DMA_ERROR_CODE
	15	#define DMA_ERROR_CODE (~(dma_addr_t)0x0)
	16	#endif
	17
b0cc836d	18	static unsigned long iommu_large_alloc = 15;
ff7d37a5	19
7b3372d4	20	static DEFINE_PER_CPU(unsigned int, iommu_hash_common);
ff7d37a5 SV	21
	22	static inline bool need_flush(struct iommu_map_table *iommu)
	23	{
	24	return (iommu->lazy_flush != NULL &&
	25	(iommu->flags & IOMMU_NEED_FLUSH) != 0);
	26	}
	27
	28	static inline void set_flush(struct iommu_map_table *iommu)
	29	{
	30	iommu->flags \|= IOMMU_NEED_FLUSH;
	31	}
	32
	33	static inline void clear_flush(struct iommu_map_table *iommu)
	34	{
	35	iommu->flags &= ~IOMMU_NEED_FLUSH;
	36	}
	37
	38	static void setup_iommu_pool_hash(void)
	39	{
	40	unsigned int i;
	41	static bool do_once;
	42
	43	if (do_once)
	44	return;
	45	do_once = true;
	46	for_each_possible_cpu(i)
7b3372d4	47	per_cpu(iommu_hash_common, i) = hash_32(i, IOMMU_POOL_HASHBITS);
ff7d37a5 SV	48	}
	49
	50	/*
	51	* Initialize iommu_pool entries for the iommu_map_table. `num_entries'
	52	* is the number of table entries. If `large_pool' is set to true,
	53	* the top 1/4 of the table will be set aside for pool allocations
	54	* of more than iommu_large_alloc pages.
	55	*/
b0cc836d SV	56	void iommu_tbl_pool_init(struct iommu_map_table *iommu,
	57	unsigned long num_entries,
	58	u32 table_shift,
	59	void (lazy_flush)(struct iommu_map_table ),
	60	bool large_pool, u32 npools,
	61	bool skip_span_boundary_check)
ff7d37a5 SV	62	{
	63	unsigned int start, i;
	64	struct iommu_pool *p = &(iommu->large_pool);
	65
	66	setup_iommu_pool_hash();
	67	if (npools == 0)
	68	iommu->nr_pools = IOMMU_NR_POOLS;
	69	else
	70	iommu->nr_pools = npools;
	71	BUG_ON(npools > IOMMU_NR_POOLS);
	72
	73	iommu->table_shift = table_shift;
	74	iommu->lazy_flush = lazy_flush;
	75	start = 0;
	76	if (skip_span_boundary_check)
	77	iommu->flags \|= IOMMU_NO_SPAN_BOUND;
	78	if (large_pool)
	79	iommu->flags \|= IOMMU_HAS_LARGE_POOL;
	80
	81	if (!large_pool)
	82	iommu->poolsize = num_entries/iommu->nr_pools;
	83	else
	84	iommu->poolsize = (num_entries * 3 / 4)/iommu->nr_pools;
	85	for (i = 0; i < iommu->nr_pools; i++) {
	86	spin_lock_init(&(iommu->pools[i].lock));
	87	iommu->pools[i].start = start;
	88	iommu->pools[i].hint = start;
	89	start += iommu->poolsize; /* start for next pool */
	90	iommu->pools[i].end = start - 1;
	91	}
	92	if (!large_pool)
	93	return;
	94	/* initialize large_pool */
	95	spin_lock_init(&(p->lock));
	96	p->start = start;
	97	p->hint = p->start;
	98	p->end = num_entries;
	99	}
	100	EXPORT_SYMBOL(iommu_tbl_pool_init);
	101
	102	unsigned long iommu_tbl_range_alloc(struct device *dev,
	103	struct iommu_map_table *iommu,
	104	unsigned long npages,
	105	unsigned long *handle,
	106	unsigned long mask,
	107	unsigned int align_order)
	108	{
7b3372d4	109	unsigned int pool_hash = __this_cpu_read(iommu_hash_common);
ff7d37a5 SV	110	unsigned long n, end, start, limit, boundary_size;
	111	struct iommu_pool *pool;
	112	int pass = 0;
	113	unsigned int pool_nr;
	114	unsigned int npools = iommu->nr_pools;
	115	unsigned long flags;
	116	bool large_pool = ((iommu->flags & IOMMU_HAS_LARGE_POOL) != 0);
	117	bool largealloc = (large_pool && npages > iommu_large_alloc);
	118	unsigned long shift;
	119	unsigned long align_mask = 0;
	120
	121	if (align_order > 0)
447f6a95	122	align_mask = ~0ul >> (BITS_PER_LONG - align_order);
ff7d37a5 SV	123
	124	/* Sanity check */
	125	if (unlikely(npages == 0)) {
	126	WARN_ON_ONCE(1);
	127	return DMA_ERROR_CODE;
	128	}
	129
	130	if (largealloc) {
	131	pool = &(iommu->large_pool);
	132	pool_nr = 0; /* to keep compiler happy */
	133	} else {
	134	/* pick out pool_nr */
	135	pool_nr = pool_hash & (npools - 1);
	136	pool = &(iommu->pools[pool_nr]);
	137	}
	138	spin_lock_irqsave(&pool->lock, flags);
	139
	140	again:
	141	if (pass == 0 && handle && *handle &&
	142	(handle >= pool->start) && (handle < pool->end))
	143	start = *handle;
	144	else
	145	start = pool->hint;
	146
	147	limit = pool->end;
	148
	149	/* The case below can happen if we have a small segment appended
	150	* to a large, or when the previous alloc was at the very end of
	151	* the available space. If so, go back to the beginning. If a
	152	* flush is needed, it will get done based on the return value
	153	* from iommu_area_alloc() below.
	154	*/
	155	if (start >= limit)
	156	start = pool->start;
	157	shift = iommu->table_map_base >> iommu->table_shift;
	158	if (limit + shift > mask) {
	159	limit = mask - shift + 1;
	160	/* If we're constrained on address range, first try
	161	* at the masked hint to avoid O(n) search complexity,
	162	* but on second pass, start at 0 in pool 0.
	163	*/
	164	if ((start & mask) >= limit \|\| pass > 0) {
	165	spin_unlock(&(pool->lock));
	166	pool = &(iommu->pools[0]);
	167	spin_lock(&(pool->lock));
	168	start = pool->start;
	169	} else {
	170	start &= mask;
	171	}
	172	}
	173
	174	if (dev)
	175	boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
	176	1 << iommu->table_shift);
	177	else
2f0c0fdc	178	boundary_size = ALIGN(1ULL << 32, 1 << iommu->table_shift);
ff7d37a5 SV	179
	180	boundary_size = boundary_size >> iommu->table_shift;
	181	/*
	182	* if the skip_span_boundary_check had been set during init, we set
	183	* things up so that iommu_is_span_boundary() merely checks if the
	184	* (index + npages) < num_tsb_entries
	185	*/
	186	if ((iommu->flags & IOMMU_NO_SPAN_BOUND) != 0) {
	187	shift = 0;
	188	boundary_size = iommu->poolsize * iommu->nr_pools;
	189	}
	190	n = iommu_area_alloc(iommu->map, limit, start, npages, shift,
	191	boundary_size, align_mask);
	192	if (n == -1) {
	193	if (likely(pass == 0)) {
	194	/* First failure, rescan from the beginning. */
	195	pool->hint = pool->start;
	196	set_flush(iommu);
	197	pass++;
	198	goto again;
	199	} else if (!largealloc && pass <= iommu->nr_pools) {
	200	spin_unlock(&(pool->lock));
	201	pool_nr = (pool_nr + 1) & (iommu->nr_pools - 1);
	202	pool = &(iommu->pools[pool_nr]);
	203	spin_lock(&(pool->lock));
	204	pool->hint = pool->start;
	205	set_flush(iommu);
	206	pass++;
	207	goto again;
	208	} else {
	209	/* give up */
	210	n = DMA_ERROR_CODE;
	211	goto bail;
	212	}
	213	}
	214	if (n < pool->hint \|\| need_flush(iommu)) {
	215	clear_flush(iommu);
	216	iommu->lazy_flush(iommu);
	217	}
	218
	219	end = n + npages;
	220	pool->hint = end;
	221
	222	/* Update handle for SG allocations */
	223	if (handle)
	224	*handle = end;
	225	bail:
	226	spin_unlock_irqrestore(&(pool->lock), flags);
	227
	228	return n;
	229	}
	230	EXPORT_SYMBOL(iommu_tbl_range_alloc);
	231
	232	static struct iommu_pool get_pool(struct iommu_map_table tbl,
	233	unsigned long entry)
	234	{
	235	struct iommu_pool *p;
	236	unsigned long largepool_start = tbl->large_pool.start;
	237	bool large_pool = ((tbl->flags & IOMMU_HAS_LARGE_POOL) != 0);
	238
	239	/* The large pool is the last pool at the top of the table */
	240	if (large_pool && entry >= largepool_start) {
	241	p = &tbl->large_pool;
	242	} else {
243	unsigned int pool_nr = entry / tbl->poolsize;
244
245	BUG_ON(pool_nr >= tbl->nr_pools);
246	p = &tbl->pools[pool_nr];
247	}
248	return p;
249	}
250
251	/* Caller supplies the index of the entry into the iommu map table
252	* itself when the mapping from dma_addr to the entry is not the
253	* default addr->entry mapping below.
254	*/
255	void iommu_tbl_range_free(struct iommu_map_table *iommu, u64 dma_addr,
256	unsigned long npages, unsigned long entry)
257	{
258	struct iommu_pool *pool;
259	unsigned long flags;
260	unsigned long shift = iommu->table_shift;
261
262	if (entry == DMA_ERROR_CODE) /* use default addr->entry mapping */
263	entry = (dma_addr - iommu->table_map_base) >> shift;
264	pool = get_pool(iommu, entry);
265
266	spin_lock_irqsave(&(pool->lock), flags);
267	bitmap_clear(iommu->map, entry, npages);
268	spin_unlock_irqrestore(&(pool->lock), flags);
269	}
270	EXPORT_SYMBOL(iommu_tbl_range_free);