2 * IOMMU mmap management and range allocation functions.
3 * Based almost entirely upon the powerpc iommu allocator.
6 #include <linux/export.h>
7 #include <linux/bitmap.h>
9 #include <linux/iommu-helper.h>
10 #include <linux/iommu-common.h>
11 #include <linux/dma-mapping.h>
12 #include <linux/hash.h>
14 #ifndef DMA_ERROR_CODE
15 #define DMA_ERROR_CODE (~(dma_addr_t)0x0)
18 static unsigned long iommu_large_alloc = 15;
20 static DEFINE_PER_CPU(unsigned int, iommu_hash_common);
22 static inline bool need_flush(struct iommu_map_table *iommu)
24 return (iommu->lazy_flush != NULL &&
25 (iommu->flags & IOMMU_NEED_FLUSH) != 0);
28 static inline void set_flush(struct iommu_map_table *iommu)
30 iommu->flags |= IOMMU_NEED_FLUSH;
33 static inline void clear_flush(struct iommu_map_table *iommu)
35 iommu->flags &= ~IOMMU_NEED_FLUSH;
38 static void setup_iommu_pool_hash(void)
46 for_each_possible_cpu(i)
47 per_cpu(iommu_hash_common, i) = hash_32(i, IOMMU_POOL_HASHBITS);
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.
56 void iommu_tbl_pool_init(struct iommu_map_table *iommu,
57 unsigned long num_entries,
59 void (*lazy_flush)(struct iommu_map_table *),
60 bool large_pool, u32 npools,
61 bool skip_span_boundary_check)
63 unsigned int start, i;
64 struct iommu_pool *p = &(iommu->large_pool);
66 setup_iommu_pool_hash();
68 iommu->nr_pools = IOMMU_NR_POOLS;
70 iommu->nr_pools = npools;
71 BUG_ON(npools > IOMMU_NR_POOLS);
73 iommu->table_shift = table_shift;
74 iommu->lazy_flush = lazy_flush;
76 if (skip_span_boundary_check)
77 iommu->flags |= IOMMU_NO_SPAN_BOUND;
79 iommu->flags |= IOMMU_HAS_LARGE_POOL;
82 iommu->poolsize = num_entries/iommu->nr_pools;
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;
94 /* initialize large_pool */
95 spin_lock_init(&(p->lock));
100 EXPORT_SYMBOL(iommu_tbl_pool_init);
102 unsigned long iommu_tbl_range_alloc(struct device *dev,
103 struct iommu_map_table *iommu,
104 unsigned long npages,
105 unsigned long *handle,
107 unsigned int align_order)
109 unsigned int pool_hash = __this_cpu_read(iommu_hash_common);
110 unsigned long n, end, start, limit, boundary_size;
111 struct iommu_pool *pool;
113 unsigned int pool_nr;
114 unsigned int npools = iommu->nr_pools;
116 bool large_pool = ((iommu->flags & IOMMU_HAS_LARGE_POOL) != 0);
117 bool largealloc = (large_pool && npages > iommu_large_alloc);
119 unsigned long align_mask = 0;
122 align_mask = 0xffffffffffffffffl >> (64 - align_order);
125 if (unlikely(npages == 0)) {
127 return DMA_ERROR_CODE;
131 pool = &(iommu->large_pool);
132 pool_nr = 0; /* to keep compiler happy */
134 /* pick out pool_nr */
135 pool_nr = pool_hash & (npools - 1);
136 pool = &(iommu->pools[pool_nr]);
138 spin_lock_irqsave(&pool->lock, flags);
141 if (pass == 0 && handle && *handle &&
142 (*handle >= pool->start) && (*handle < pool->end))
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.
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.
164 if ((start & mask) >= limit || pass > 0) {
165 spin_unlock(&(pool->lock));
166 pool = &(iommu->pools[0]);
167 spin_lock(&(pool->lock));
175 boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
176 1 << iommu->table_shift);
178 boundary_size = ALIGN(1ULL << 32, 1 << iommu->table_shift);
180 boundary_size = boundary_size >> iommu->table_shift;
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
186 if ((iommu->flags & IOMMU_NO_SPAN_BOUND) != 0) {
188 boundary_size = iommu->poolsize * iommu->nr_pools;
190 n = iommu_area_alloc(iommu->map, limit, start, npages, shift,
191 boundary_size, align_mask);
193 if (likely(pass == 0)) {
194 /* First failure, rescan from the beginning. */
195 pool->hint = pool->start;
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;
214 if (n < pool->hint || need_flush(iommu)) {
216 iommu->lazy_flush(iommu);
222 /* Update handle for SG allocations */
226 spin_unlock_irqrestore(&(pool->lock), flags);
230 EXPORT_SYMBOL(iommu_tbl_range_alloc);
232 static struct iommu_pool *get_pool(struct iommu_map_table *tbl,
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);
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;
243 unsigned int pool_nr = entry / tbl->poolsize;
245 BUG_ON(pool_nr >= tbl->nr_pools);
246 p = &tbl->pools[pool_nr];
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.
255 void iommu_tbl_range_free(struct iommu_map_table *iommu, u64 dma_addr,
256 unsigned long npages, unsigned long entry)
258 struct iommu_pool *pool;
260 unsigned long shift = iommu->table_shift;
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);
266 spin_lock_irqsave(&(pool->lock), flags);
267 bitmap_clear(iommu->map, entry, npages);
268 spin_unlock_irqrestore(&(pool->lock), flags);
270 EXPORT_SYMBOL(iommu_tbl_range_free);