2 * Copyright © 2006-2009, Intel Corporation.
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms and conditions of the GNU General Public License,
6 * version 2, as published by the Free Software Foundation.
8 * This program is distributed in the hope it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * You should have received a copy of the GNU General Public License along with
14 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
15 * Place - Suite 330, Boston, MA 02111-1307 USA.
17 * Author: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
20 #include <linux/iova.h>
23 init_iova_domain(struct iova_domain *iovad, unsigned long pfn_32bit)
25 spin_lock_init(&iovad->iova_alloc_lock);
26 spin_lock_init(&iovad->iova_rbtree_lock);
27 iovad->rbroot = RB_ROOT;
28 iovad->cached32_node = NULL;
29 iovad->dma_32bit_pfn = pfn_32bit;
32 static struct rb_node *
33 __get_cached_rbnode(struct iova_domain *iovad, unsigned long *limit_pfn)
35 if ((*limit_pfn != iovad->dma_32bit_pfn) ||
36 (iovad->cached32_node == NULL))
37 return rb_last(&iovad->rbroot);
39 struct rb_node *prev_node = rb_prev(iovad->cached32_node);
40 struct iova *curr_iova =
41 container_of(iovad->cached32_node, struct iova, node);
42 *limit_pfn = curr_iova->pfn_lo - 1;
48 __cached_rbnode_insert_update(struct iova_domain *iovad,
49 unsigned long limit_pfn, struct iova *new)
51 if (limit_pfn != iovad->dma_32bit_pfn)
53 iovad->cached32_node = &new->node;
57 __cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free)
59 struct iova *cached_iova;
62 if (!iovad->cached32_node)
64 curr = iovad->cached32_node;
65 cached_iova = container_of(curr, struct iova, node);
67 if (free->pfn_lo >= cached_iova->pfn_lo)
68 iovad->cached32_node = rb_next(&free->node);
71 /* Computes the padding size required, to make the
72 * the start address naturally aligned on its size
75 iova_get_pad_size(int size, unsigned int limit_pfn)
77 unsigned int pad_size = 0;
78 unsigned int order = ilog2(size);
81 pad_size = (limit_pfn + 1) % (1 << order);
86 static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
87 unsigned long size, unsigned long limit_pfn,
88 struct iova *new, bool size_aligned)
90 struct rb_node *prev, *curr = NULL;
92 unsigned long saved_pfn;
93 unsigned int pad_size = 0;
95 /* Walk the tree backwards */
96 spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
97 saved_pfn = limit_pfn;
98 curr = __get_cached_rbnode(iovad, &limit_pfn);
101 struct iova *curr_iova = container_of(curr, struct iova, node);
103 if (limit_pfn < curr_iova->pfn_lo)
105 else if (limit_pfn < curr_iova->pfn_hi)
106 goto adjust_limit_pfn;
109 pad_size = iova_get_pad_size(size, limit_pfn);
110 if ((curr_iova->pfn_hi + size + pad_size) <= limit_pfn)
111 break; /* found a free slot */
114 limit_pfn = curr_iova->pfn_lo - 1;
117 curr = rb_prev(curr);
122 pad_size = iova_get_pad_size(size, limit_pfn);
123 if ((IOVA_START_PFN + size + pad_size) > limit_pfn) {
124 spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
129 /* pfn_lo will point to size aligned address if size_aligned is set */
130 new->pfn_lo = limit_pfn - (size + pad_size) + 1;
131 new->pfn_hi = new->pfn_lo + size - 1;
133 /* Insert the new_iova into domain rbtree by holding writer lock */
134 /* Add new node and rebalance tree. */
136 struct rb_node **entry, *parent = NULL;
138 /* If we have 'prev', it's a valid place to start the
139 insertion. Otherwise, start from the root. */
143 entry = &iovad->rbroot.rb_node;
145 /* Figure out where to put new node */
147 struct iova *this = container_of(*entry,
151 if (new->pfn_lo < this->pfn_lo)
152 entry = &((*entry)->rb_left);
153 else if (new->pfn_lo > this->pfn_lo)
154 entry = &((*entry)->rb_right);
156 BUG(); /* this should not happen */
159 /* Add new node and rebalance tree. */
160 rb_link_node(&new->node, parent, entry);
161 rb_insert_color(&new->node, &iovad->rbroot);
163 __cached_rbnode_insert_update(iovad, saved_pfn, new);
165 spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
172 iova_insert_rbtree(struct rb_root *root, struct iova *iova)
174 struct rb_node **new = &(root->rb_node), *parent = NULL;
175 /* Figure out where to put new node */
177 struct iova *this = container_of(*new, struct iova, node);
180 if (iova->pfn_lo < this->pfn_lo)
181 new = &((*new)->rb_left);
182 else if (iova->pfn_lo > this->pfn_lo)
183 new = &((*new)->rb_right);
185 BUG(); /* this should not happen */
187 /* Add new node and rebalance tree. */
188 rb_link_node(&iova->node, parent, new);
189 rb_insert_color(&iova->node, root);
193 * alloc_iova - allocates an iova
194 * @iovad - iova domain in question
195 * @size - size of page frames to allocate
196 * @limit_pfn - max limit address
197 * @size_aligned - set if size_aligned address range is required
198 * This function allocates an iova in the range limit_pfn to IOVA_START_PFN
199 * looking from limit_pfn instead from IOVA_START_PFN. If the size_aligned
200 * flag is set then the allocated address iova->pfn_lo will be naturally
201 * aligned on roundup_power_of_two(size).
204 alloc_iova(struct iova_domain *iovad, unsigned long size,
205 unsigned long limit_pfn,
209 struct iova *new_iova;
212 new_iova = alloc_iova_mem();
216 /* If size aligned is set then round the size to
217 * to next power of two.
220 size = __roundup_pow_of_two(size);
222 spin_lock_irqsave(&iovad->iova_alloc_lock, flags);
223 ret = __alloc_and_insert_iova_range(iovad, size, limit_pfn,
224 new_iova, size_aligned);
226 spin_unlock_irqrestore(&iovad->iova_alloc_lock, flags);
228 free_iova_mem(new_iova);
236 * find_iova - find's an iova for a given pfn
237 * @iovad - iova domain in question.
238 * pfn - page frame number
239 * This function finds and returns an iova belonging to the
240 * given doamin which matches the given pfn.
242 struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn)
245 struct rb_node *node;
247 /* Take the lock so that no other thread is manipulating the rbtree */
248 spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
249 node = iovad->rbroot.rb_node;
251 struct iova *iova = container_of(node, struct iova, node);
253 /* If pfn falls within iova's range, return iova */
254 if ((pfn >= iova->pfn_lo) && (pfn <= iova->pfn_hi)) {
255 spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
256 /* We are not holding the lock while this iova
257 * is referenced by the caller as the same thread
258 * which called this function also calls __free_iova()
259 * and it is by desing that only one thread can possibly
260 * reference a particular iova and hence no conflict.
265 if (pfn < iova->pfn_lo)
266 node = node->rb_left;
267 else if (pfn > iova->pfn_lo)
268 node = node->rb_right;
271 spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
276 * __free_iova - frees the given iova
277 * @iovad: iova domain in question.
278 * @iova: iova in question.
279 * Frees the given iova belonging to the giving domain
282 __free_iova(struct iova_domain *iovad, struct iova *iova)
286 spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
287 __cached_rbnode_delete_update(iovad, iova);
288 rb_erase(&iova->node, &iovad->rbroot);
289 spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
294 * free_iova - finds and frees the iova for a given pfn
295 * @iovad: - iova domain in question.
296 * @pfn: - pfn that is allocated previously
297 * This functions finds an iova for a given pfn and then
298 * frees the iova from that domain.
301 free_iova(struct iova_domain *iovad, unsigned long pfn)
303 struct iova *iova = find_iova(iovad, pfn);
305 __free_iova(iovad, iova);
310 * put_iova_domain - destroys the iova doamin
311 * @iovad: - iova domain in question.
312 * All the iova's in that domain are destroyed.
314 void put_iova_domain(struct iova_domain *iovad)
316 struct rb_node *node;
319 spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
320 node = rb_first(&iovad->rbroot);
322 struct iova *iova = container_of(node, struct iova, node);
323 rb_erase(node, &iovad->rbroot);
325 node = rb_first(&iovad->rbroot);
327 spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
331 __is_range_overlap(struct rb_node *node,
332 unsigned long pfn_lo, unsigned long pfn_hi)
334 struct iova *iova = container_of(node, struct iova, node);
336 if ((pfn_lo <= iova->pfn_hi) && (pfn_hi >= iova->pfn_lo))
342 __insert_new_range(struct iova_domain *iovad,
343 unsigned long pfn_lo, unsigned long pfn_hi)
347 iova = alloc_iova_mem();
351 iova->pfn_hi = pfn_hi;
352 iova->pfn_lo = pfn_lo;
353 iova_insert_rbtree(&iovad->rbroot, iova);
358 __adjust_overlap_range(struct iova *iova,
359 unsigned long *pfn_lo, unsigned long *pfn_hi)
361 if (*pfn_lo < iova->pfn_lo)
362 iova->pfn_lo = *pfn_lo;
363 if (*pfn_hi > iova->pfn_hi)
364 *pfn_lo = iova->pfn_hi + 1;
368 * reserve_iova - reserves an iova in the given range
369 * @iovad: - iova domain pointer
370 * @pfn_lo: - lower page frame address
371 * @pfn_hi:- higher pfn adderss
372 * This function allocates reserves the address range from pfn_lo to pfn_hi so
373 * that this address is not dished out as part of alloc_iova.
376 reserve_iova(struct iova_domain *iovad,
377 unsigned long pfn_lo, unsigned long pfn_hi)
379 struct rb_node *node;
382 unsigned int overlap = 0;
384 spin_lock_irqsave(&iovad->iova_alloc_lock, flags);
385 spin_lock(&iovad->iova_rbtree_lock);
386 for (node = rb_first(&iovad->rbroot); node; node = rb_next(node)) {
387 if (__is_range_overlap(node, pfn_lo, pfn_hi)) {
388 iova = container_of(node, struct iova, node);
389 __adjust_overlap_range(iova, &pfn_lo, &pfn_hi);
390 if ((pfn_lo >= iova->pfn_lo) &&
391 (pfn_hi <= iova->pfn_hi))
399 /* We are here either becasue this is the first reserver node
400 * or need to insert remaining non overlap addr range
402 iova = __insert_new_range(iovad, pfn_lo, pfn_hi);
405 spin_unlock(&iovad->iova_rbtree_lock);
406 spin_unlock_irqrestore(&iovad->iova_alloc_lock, flags);
411 * copy_reserved_iova - copies the reserved between domains
412 * @from: - source doamin from where to copy
413 * @to: - destination domin where to copy
414 * This function copies reserved iova's from one doamin to
418 copy_reserved_iova(struct iova_domain *from, struct iova_domain *to)
421 struct rb_node *node;
423 spin_lock_irqsave(&from->iova_alloc_lock, flags);
424 spin_lock(&from->iova_rbtree_lock);
425 for (node = rb_first(&from->rbroot); node; node = rb_next(node)) {
426 struct iova *iova = container_of(node, struct iova, node);
427 struct iova *new_iova;
428 new_iova = reserve_iova(to, iova->pfn_lo, iova->pfn_hi);
430 printk(KERN_ERR "Reserve iova range %lx@%lx failed\n",
431 iova->pfn_lo, iova->pfn_lo);
433 spin_unlock(&from->iova_rbtree_lock);
434 spin_unlock_irqrestore(&from->iova_alloc_lock, flags);