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