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f8de50eb KA |
1 | /* |
2 | * Copyright (c) 2006, Intel Corporation. | |
3 | * | |
4 | * This file is released under the GPLv2. | |
5 | * | |
6 | * Copyright (C) 2006 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> | |
7 | */ | |
8 | ||
9 | #include "iova.h" | |
10 | ||
11 | void | |
12 | init_iova_domain(struct iova_domain *iovad) | |
13 | { | |
14 | spin_lock_init(&iovad->iova_alloc_lock); | |
15 | spin_lock_init(&iovad->iova_rbtree_lock); | |
16 | iovad->rbroot = RB_ROOT; | |
17 | iovad->cached32_node = NULL; | |
18 | ||
19 | } | |
20 | ||
21 | static struct rb_node * | |
22 | __get_cached_rbnode(struct iova_domain *iovad, unsigned long *limit_pfn) | |
23 | { | |
24 | if ((*limit_pfn != DMA_32BIT_PFN) || | |
25 | (iovad->cached32_node == NULL)) | |
26 | return rb_last(&iovad->rbroot); | |
27 | else { | |
28 | struct rb_node *prev_node = rb_prev(iovad->cached32_node); | |
29 | struct iova *curr_iova = | |
30 | container_of(iovad->cached32_node, struct iova, node); | |
31 | *limit_pfn = curr_iova->pfn_lo - 1; | |
32 | return prev_node; | |
33 | } | |
34 | } | |
35 | ||
36 | static void | |
37 | __cached_rbnode_insert_update(struct iova_domain *iovad, | |
38 | unsigned long limit_pfn, struct iova *new) | |
39 | { | |
40 | if (limit_pfn != DMA_32BIT_PFN) | |
41 | return; | |
42 | iovad->cached32_node = &new->node; | |
43 | } | |
44 | ||
45 | static void | |
46 | __cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free) | |
47 | { | |
48 | struct iova *cached_iova; | |
49 | struct rb_node *curr; | |
50 | ||
51 | if (!iovad->cached32_node) | |
52 | return; | |
53 | curr = iovad->cached32_node; | |
54 | cached_iova = container_of(curr, struct iova, node); | |
55 | ||
56 | if (free->pfn_lo >= cached_iova->pfn_lo) | |
57 | iovad->cached32_node = rb_next(&free->node); | |
58 | } | |
59 | ||
f76aec76 KA |
60 | /* Computes the padding size required, to make the |
61 | * the start address naturally aligned on its size | |
62 | */ | |
63 | static int | |
64 | iova_get_pad_size(int size, unsigned int limit_pfn) | |
65 | { | |
66 | unsigned int pad_size = 0; | |
67 | unsigned int order = ilog2(size); | |
68 | ||
69 | if (order) | |
70 | pad_size = (limit_pfn + 1) % (1 << order); | |
71 | ||
72 | return pad_size; | |
73 | } | |
74 | ||
75 | static int __alloc_iova_range(struct iova_domain *iovad, unsigned long size, | |
76 | unsigned long limit_pfn, struct iova *new, bool size_aligned) | |
f8de50eb KA |
77 | { |
78 | struct rb_node *curr = NULL; | |
79 | unsigned long flags; | |
80 | unsigned long saved_pfn; | |
f76aec76 | 81 | unsigned int pad_size = 0; |
f8de50eb KA |
82 | |
83 | /* Walk the tree backwards */ | |
84 | spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); | |
85 | saved_pfn = limit_pfn; | |
86 | curr = __get_cached_rbnode(iovad, &limit_pfn); | |
87 | while (curr) { | |
88 | struct iova *curr_iova = container_of(curr, struct iova, node); | |
89 | if (limit_pfn < curr_iova->pfn_lo) | |
90 | goto move_left; | |
f76aec76 | 91 | else if (limit_pfn < curr_iova->pfn_hi) |
f8de50eb | 92 | goto adjust_limit_pfn; |
f76aec76 KA |
93 | else { |
94 | if (size_aligned) | |
95 | pad_size = iova_get_pad_size(size, limit_pfn); | |
96 | if ((curr_iova->pfn_hi + size + pad_size) <= limit_pfn) | |
97 | break; /* found a free slot */ | |
98 | } | |
f8de50eb KA |
99 | adjust_limit_pfn: |
100 | limit_pfn = curr_iova->pfn_lo - 1; | |
101 | move_left: | |
102 | curr = rb_prev(curr); | |
103 | } | |
104 | ||
f76aec76 KA |
105 | if (!curr) { |
106 | if (size_aligned) | |
107 | pad_size = iova_get_pad_size(size, limit_pfn); | |
108 | if ((IOVA_START_PFN + size + pad_size) > limit_pfn) { | |
109 | spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); | |
110 | return -ENOMEM; | |
111 | } | |
f8de50eb | 112 | } |
f76aec76 KA |
113 | |
114 | /* pfn_lo will point to size aligned address if size_aligned is set */ | |
115 | new->pfn_lo = limit_pfn - (size + pad_size) + 1; | |
116 | new->pfn_hi = new->pfn_lo + size - 1; | |
f8de50eb KA |
117 | |
118 | spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); | |
119 | return 0; | |
120 | } | |
121 | ||
122 | static void | |
123 | iova_insert_rbtree(struct rb_root *root, struct iova *iova) | |
124 | { | |
125 | struct rb_node **new = &(root->rb_node), *parent = NULL; | |
126 | /* Figure out where to put new node */ | |
127 | while (*new) { | |
128 | struct iova *this = container_of(*new, struct iova, node); | |
129 | parent = *new; | |
130 | ||
131 | if (iova->pfn_lo < this->pfn_lo) | |
132 | new = &((*new)->rb_left); | |
133 | else if (iova->pfn_lo > this->pfn_lo) | |
134 | new = &((*new)->rb_right); | |
135 | else | |
136 | BUG(); /* this should not happen */ | |
137 | } | |
138 | /* Add new node and rebalance tree. */ | |
139 | rb_link_node(&iova->node, parent, new); | |
140 | rb_insert_color(&iova->node, root); | |
141 | } | |
142 | ||
143 | /** | |
144 | * alloc_iova - allocates an iova | |
145 | * @iovad - iova domain in question | |
146 | * @size - size of page frames to allocate | |
147 | * @limit_pfn - max limit address | |
f76aec76 | 148 | * @size_aligned - set if size_aligned address range is required |
f8de50eb | 149 | * This function allocates an iova in the range limit_pfn to IOVA_START_PFN |
f76aec76 KA |
150 | * looking from limit_pfn instead from IOVA_START_PFN. If the size_aligned |
151 | * flag is set then the allocated address iova->pfn_lo will be naturally | |
152 | * aligned on roundup_power_of_two(size). | |
f8de50eb KA |
153 | */ |
154 | struct iova * | |
155 | alloc_iova(struct iova_domain *iovad, unsigned long size, | |
f76aec76 KA |
156 | unsigned long limit_pfn, |
157 | bool size_aligned) | |
f8de50eb KA |
158 | { |
159 | unsigned long flags; | |
160 | struct iova *new_iova; | |
161 | int ret; | |
162 | ||
163 | new_iova = alloc_iova_mem(); | |
164 | if (!new_iova) | |
165 | return NULL; | |
166 | ||
f76aec76 KA |
167 | /* If size aligned is set then round the size to |
168 | * to next power of two. | |
169 | */ | |
170 | if (size_aligned) | |
171 | size = __roundup_pow_of_two(size); | |
172 | ||
f8de50eb | 173 | spin_lock_irqsave(&iovad->iova_alloc_lock, flags); |
f76aec76 KA |
174 | ret = __alloc_iova_range(iovad, size, limit_pfn, new_iova, |
175 | size_aligned); | |
f8de50eb KA |
176 | |
177 | if (ret) { | |
178 | spin_unlock_irqrestore(&iovad->iova_alloc_lock, flags); | |
179 | free_iova_mem(new_iova); | |
180 | return NULL; | |
181 | } | |
182 | ||
183 | /* Insert the new_iova into domain rbtree by holding writer lock */ | |
184 | spin_lock(&iovad->iova_rbtree_lock); | |
185 | iova_insert_rbtree(&iovad->rbroot, new_iova); | |
186 | __cached_rbnode_insert_update(iovad, limit_pfn, new_iova); | |
187 | spin_unlock(&iovad->iova_rbtree_lock); | |
188 | ||
189 | spin_unlock_irqrestore(&iovad->iova_alloc_lock, flags); | |
190 | ||
191 | return new_iova; | |
192 | } | |
193 | ||
194 | /** | |
195 | * find_iova - find's an iova for a given pfn | |
196 | * @iovad - iova domain in question. | |
197 | * pfn - page frame number | |
198 | * This function finds and returns an iova belonging to the | |
199 | * given doamin which matches the given pfn. | |
200 | */ | |
201 | struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn) | |
202 | { | |
203 | unsigned long flags; | |
204 | struct rb_node *node; | |
205 | ||
206 | /* Take the lock so that no other thread is manipulating the rbtree */ | |
207 | spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); | |
208 | node = iovad->rbroot.rb_node; | |
209 | while (node) { | |
210 | struct iova *iova = container_of(node, struct iova, node); | |
211 | ||
212 | /* If pfn falls within iova's range, return iova */ | |
213 | if ((pfn >= iova->pfn_lo) && (pfn <= iova->pfn_hi)) { | |
214 | spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); | |
215 | /* We are not holding the lock while this iova | |
216 | * is referenced by the caller as the same thread | |
217 | * which called this function also calls __free_iova() | |
218 | * and it is by desing that only one thread can possibly | |
219 | * reference a particular iova and hence no conflict. | |
220 | */ | |
221 | return iova; | |
222 | } | |
223 | ||
224 | if (pfn < iova->pfn_lo) | |
225 | node = node->rb_left; | |
226 | else if (pfn > iova->pfn_lo) | |
227 | node = node->rb_right; | |
228 | } | |
229 | ||
230 | spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); | |
231 | return NULL; | |
232 | } | |
233 | ||
234 | /** | |
235 | * __free_iova - frees the given iova | |
236 | * @iovad: iova domain in question. | |
237 | * @iova: iova in question. | |
238 | * Frees the given iova belonging to the giving domain | |
239 | */ | |
240 | void | |
241 | __free_iova(struct iova_domain *iovad, struct iova *iova) | |
242 | { | |
243 | unsigned long flags; | |
244 | ||
245 | spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); | |
246 | __cached_rbnode_delete_update(iovad, iova); | |
247 | rb_erase(&iova->node, &iovad->rbroot); | |
248 | spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); | |
249 | free_iova_mem(iova); | |
250 | } | |
251 | ||
252 | /** | |
253 | * free_iova - finds and frees the iova for a given pfn | |
254 | * @iovad: - iova domain in question. | |
255 | * @pfn: - pfn that is allocated previously | |
256 | * This functions finds an iova for a given pfn and then | |
257 | * frees the iova from that domain. | |
258 | */ | |
259 | void | |
260 | free_iova(struct iova_domain *iovad, unsigned long pfn) | |
261 | { | |
262 | struct iova *iova = find_iova(iovad, pfn); | |
263 | if (iova) | |
264 | __free_iova(iovad, iova); | |
265 | ||
266 | } | |
267 | ||
268 | /** | |
269 | * put_iova_domain - destroys the iova doamin | |
270 | * @iovad: - iova domain in question. | |
271 | * All the iova's in that domain are destroyed. | |
272 | */ | |
273 | void put_iova_domain(struct iova_domain *iovad) | |
274 | { | |
275 | struct rb_node *node; | |
276 | unsigned long flags; | |
277 | ||
278 | spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); | |
279 | node = rb_first(&iovad->rbroot); | |
280 | while (node) { | |
281 | struct iova *iova = container_of(node, struct iova, node); | |
282 | rb_erase(node, &iovad->rbroot); | |
283 | free_iova_mem(iova); | |
284 | node = rb_first(&iovad->rbroot); | |
285 | } | |
286 | spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); | |
287 | } | |
288 | ||
289 | static int | |
290 | __is_range_overlap(struct rb_node *node, | |
291 | unsigned long pfn_lo, unsigned long pfn_hi) | |
292 | { | |
293 | struct iova *iova = container_of(node, struct iova, node); | |
294 | ||
295 | if ((pfn_lo <= iova->pfn_hi) && (pfn_hi >= iova->pfn_lo)) | |
296 | return 1; | |
297 | return 0; | |
298 | } | |
299 | ||
300 | static struct iova * | |
301 | __insert_new_range(struct iova_domain *iovad, | |
302 | unsigned long pfn_lo, unsigned long pfn_hi) | |
303 | { | |
304 | struct iova *iova; | |
305 | ||
306 | iova = alloc_iova_mem(); | |
307 | if (!iova) | |
308 | return iova; | |
309 | ||
310 | iova->pfn_hi = pfn_hi; | |
311 | iova->pfn_lo = pfn_lo; | |
312 | iova_insert_rbtree(&iovad->rbroot, iova); | |
313 | return iova; | |
314 | } | |
315 | ||
316 | static void | |
317 | __adjust_overlap_range(struct iova *iova, | |
318 | unsigned long *pfn_lo, unsigned long *pfn_hi) | |
319 | { | |
320 | if (*pfn_lo < iova->pfn_lo) | |
321 | iova->pfn_lo = *pfn_lo; | |
322 | if (*pfn_hi > iova->pfn_hi) | |
323 | *pfn_lo = iova->pfn_hi + 1; | |
324 | } | |
325 | ||
326 | /** | |
327 | * reserve_iova - reserves an iova in the given range | |
328 | * @iovad: - iova domain pointer | |
329 | * @pfn_lo: - lower page frame address | |
330 | * @pfn_hi:- higher pfn adderss | |
331 | * This function allocates reserves the address range from pfn_lo to pfn_hi so | |
332 | * that this address is not dished out as part of alloc_iova. | |
333 | */ | |
334 | struct iova * | |
335 | reserve_iova(struct iova_domain *iovad, | |
336 | unsigned long pfn_lo, unsigned long pfn_hi) | |
337 | { | |
338 | struct rb_node *node; | |
339 | unsigned long flags; | |
340 | struct iova *iova; | |
341 | unsigned int overlap = 0; | |
342 | ||
343 | spin_lock_irqsave(&iovad->iova_alloc_lock, flags); | |
344 | spin_lock(&iovad->iova_rbtree_lock); | |
345 | for (node = rb_first(&iovad->rbroot); node; node = rb_next(node)) { | |
346 | if (__is_range_overlap(node, pfn_lo, pfn_hi)) { | |
347 | iova = container_of(node, struct iova, node); | |
348 | __adjust_overlap_range(iova, &pfn_lo, &pfn_hi); | |
349 | if ((pfn_lo >= iova->pfn_lo) && | |
350 | (pfn_hi <= iova->pfn_hi)) | |
351 | goto finish; | |
352 | overlap = 1; | |
353 | ||
354 | } else if (overlap) | |
355 | break; | |
356 | } | |
357 | ||
358 | /* We are here either becasue this is the first reserver node | |
359 | * or need to insert remaining non overlap addr range | |
360 | */ | |
361 | iova = __insert_new_range(iovad, pfn_lo, pfn_hi); | |
362 | finish: | |
363 | ||
364 | spin_unlock(&iovad->iova_rbtree_lock); | |
365 | spin_unlock_irqrestore(&iovad->iova_alloc_lock, flags); | |
366 | return iova; | |
367 | } | |
368 | ||
369 | /** | |
370 | * copy_reserved_iova - copies the reserved between domains | |
371 | * @from: - source doamin from where to copy | |
372 | * @to: - destination domin where to copy | |
373 | * This function copies reserved iova's from one doamin to | |
374 | * other. | |
375 | */ | |
376 | void | |
377 | copy_reserved_iova(struct iova_domain *from, struct iova_domain *to) | |
378 | { | |
379 | unsigned long flags; | |
380 | struct rb_node *node; | |
381 | ||
382 | spin_lock_irqsave(&from->iova_alloc_lock, flags); | |
383 | spin_lock(&from->iova_rbtree_lock); | |
384 | for (node = rb_first(&from->rbroot); node; node = rb_next(node)) { | |
385 | struct iova *iova = container_of(node, struct iova, node); | |
386 | struct iova *new_iova; | |
387 | new_iova = reserve_iova(to, iova->pfn_lo, iova->pfn_hi); | |
388 | if (!new_iova) | |
389 | printk(KERN_ERR "Reserve iova range %lx@%lx failed\n", | |
390 | iova->pfn_lo, iova->pfn_lo); | |
391 | } | |
392 | spin_unlock(&from->iova_rbtree_lock); | |
393 | spin_unlock_irqrestore(&from->iova_alloc_lock, flags); | |
394 | } |