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_rbtree_lock
);
26 iovad
->rbroot
= RB_ROOT
;
27 iovad
->cached32_node
= NULL
;
28 iovad
->dma_32bit_pfn
= pfn_32bit
;
31 static struct rb_node
*
32 __get_cached_rbnode(struct iova_domain
*iovad
, unsigned long *limit_pfn
)
34 if ((*limit_pfn
!= iovad
->dma_32bit_pfn
) ||
35 (iovad
->cached32_node
== NULL
))
36 return rb_last(&iovad
->rbroot
);
38 struct rb_node
*prev_node
= rb_prev(iovad
->cached32_node
);
39 struct iova
*curr_iova
=
40 container_of(iovad
->cached32_node
, struct iova
, node
);
41 *limit_pfn
= curr_iova
->pfn_lo
- 1;
47 __cached_rbnode_insert_update(struct iova_domain
*iovad
,
48 unsigned long limit_pfn
, struct iova
*new)
50 if (limit_pfn
!= iovad
->dma_32bit_pfn
)
52 iovad
->cached32_node
= &new->node
;
56 __cached_rbnode_delete_update(struct iova_domain
*iovad
, struct iova
*free
)
58 struct iova
*cached_iova
;
61 if (!iovad
->cached32_node
)
63 curr
= iovad
->cached32_node
;
64 cached_iova
= container_of(curr
, struct iova
, node
);
66 if (free
->pfn_lo
>= cached_iova
->pfn_lo
) {
67 struct rb_node
*node
= rb_next(&free
->node
);
68 struct iova
*iova
= container_of(node
, struct iova
, node
);
70 /* only cache if it's below 32bit pfn */
71 if (node
&& iova
->pfn_lo
< iovad
->dma_32bit_pfn
)
72 iovad
->cached32_node
= node
;
74 iovad
->cached32_node
= NULL
;
78 /* Computes the padding size required, to make the
79 * the start address naturally aligned on its size
82 iova_get_pad_size(int size
, unsigned int limit_pfn
)
84 unsigned int pad_size
= 0;
85 unsigned int order
= ilog2(size
);
88 pad_size
= (limit_pfn
+ 1) % (1 << order
);
93 static int __alloc_and_insert_iova_range(struct iova_domain
*iovad
,
94 unsigned long size
, unsigned long limit_pfn
,
95 struct iova
*new, bool size_aligned
)
97 struct rb_node
*prev
, *curr
= NULL
;
99 unsigned long saved_pfn
;
100 unsigned int pad_size
= 0;
102 /* Walk the tree backwards */
103 spin_lock_irqsave(&iovad
->iova_rbtree_lock
, flags
);
104 saved_pfn
= limit_pfn
;
105 curr
= __get_cached_rbnode(iovad
, &limit_pfn
);
108 struct iova
*curr_iova
= container_of(curr
, struct iova
, node
);
110 if (limit_pfn
< curr_iova
->pfn_lo
)
112 else if (limit_pfn
< curr_iova
->pfn_hi
)
113 goto adjust_limit_pfn
;
116 pad_size
= iova_get_pad_size(size
, limit_pfn
);
117 if ((curr_iova
->pfn_hi
+ size
+ pad_size
) <= limit_pfn
)
118 break; /* found a free slot */
121 limit_pfn
= curr_iova
->pfn_lo
- 1;
124 curr
= rb_prev(curr
);
129 pad_size
= iova_get_pad_size(size
, limit_pfn
);
130 if ((IOVA_START_PFN
+ size
+ pad_size
) > limit_pfn
) {
131 spin_unlock_irqrestore(&iovad
->iova_rbtree_lock
, flags
);
136 /* pfn_lo will point to size aligned address if size_aligned is set */
137 new->pfn_lo
= limit_pfn
- (size
+ pad_size
) + 1;
138 new->pfn_hi
= new->pfn_lo
+ size
- 1;
140 /* Insert the new_iova into domain rbtree by holding writer lock */
141 /* Add new node and rebalance tree. */
143 struct rb_node
**entry
, *parent
= NULL
;
145 /* If we have 'prev', it's a valid place to start the
146 insertion. Otherwise, start from the root. */
150 entry
= &iovad
->rbroot
.rb_node
;
152 /* Figure out where to put new node */
154 struct iova
*this = container_of(*entry
,
158 if (new->pfn_lo
< this->pfn_lo
)
159 entry
= &((*entry
)->rb_left
);
160 else if (new->pfn_lo
> this->pfn_lo
)
161 entry
= &((*entry
)->rb_right
);
163 BUG(); /* this should not happen */
166 /* Add new node and rebalance tree. */
167 rb_link_node(&new->node
, parent
, entry
);
168 rb_insert_color(&new->node
, &iovad
->rbroot
);
170 __cached_rbnode_insert_update(iovad
, saved_pfn
, new);
172 spin_unlock_irqrestore(&iovad
->iova_rbtree_lock
, flags
);
179 iova_insert_rbtree(struct rb_root
*root
, struct iova
*iova
)
181 struct rb_node
**new = &(root
->rb_node
), *parent
= NULL
;
182 /* Figure out where to put new node */
184 struct iova
*this = container_of(*new, struct iova
, node
);
187 if (iova
->pfn_lo
< this->pfn_lo
)
188 new = &((*new)->rb_left
);
189 else if (iova
->pfn_lo
> this->pfn_lo
)
190 new = &((*new)->rb_right
);
192 BUG(); /* this should not happen */
194 /* Add new node and rebalance tree. */
195 rb_link_node(&iova
->node
, parent
, new);
196 rb_insert_color(&iova
->node
, root
);
200 * alloc_iova - allocates an iova
201 * @iovad - iova domain in question
202 * @size - size of page frames to allocate
203 * @limit_pfn - max limit address
204 * @size_aligned - set if size_aligned address range is required
205 * This function allocates an iova in the range limit_pfn to IOVA_START_PFN
206 * looking from limit_pfn instead from IOVA_START_PFN. If the size_aligned
207 * flag is set then the allocated address iova->pfn_lo will be naturally
208 * aligned on roundup_power_of_two(size).
211 alloc_iova(struct iova_domain
*iovad
, unsigned long size
,
212 unsigned long limit_pfn
,
215 struct iova
*new_iova
;
218 new_iova
= alloc_iova_mem();
222 /* If size aligned is set then round the size to
223 * to next power of two.
226 size
= __roundup_pow_of_two(size
);
228 ret
= __alloc_and_insert_iova_range(iovad
, size
, limit_pfn
,
229 new_iova
, size_aligned
);
232 free_iova_mem(new_iova
);
240 * find_iova - find's an iova for a given pfn
241 * @iovad - iova domain in question.
242 * pfn - page frame number
243 * This function finds and returns an iova belonging to the
244 * given doamin which matches the given pfn.
246 struct iova
*find_iova(struct iova_domain
*iovad
, unsigned long pfn
)
249 struct rb_node
*node
;
251 /* Take the lock so that no other thread is manipulating the rbtree */
252 spin_lock_irqsave(&iovad
->iova_rbtree_lock
, flags
);
253 node
= iovad
->rbroot
.rb_node
;
255 struct iova
*iova
= container_of(node
, struct iova
, node
);
257 /* If pfn falls within iova's range, return iova */
258 if ((pfn
>= iova
->pfn_lo
) && (pfn
<= iova
->pfn_hi
)) {
259 spin_unlock_irqrestore(&iovad
->iova_rbtree_lock
, flags
);
260 /* We are not holding the lock while this iova
261 * is referenced by the caller as the same thread
262 * which called this function also calls __free_iova()
263 * and it is by desing that only one thread can possibly
264 * reference a particular iova and hence no conflict.
269 if (pfn
< iova
->pfn_lo
)
270 node
= node
->rb_left
;
271 else if (pfn
> iova
->pfn_lo
)
272 node
= node
->rb_right
;
275 spin_unlock_irqrestore(&iovad
->iova_rbtree_lock
, flags
);
280 * __free_iova - frees the given iova
281 * @iovad: iova domain in question.
282 * @iova: iova in question.
283 * Frees the given iova belonging to the giving domain
286 __free_iova(struct iova_domain
*iovad
, struct iova
*iova
)
290 spin_lock_irqsave(&iovad
->iova_rbtree_lock
, flags
);
291 __cached_rbnode_delete_update(iovad
, iova
);
292 rb_erase(&iova
->node
, &iovad
->rbroot
);
293 spin_unlock_irqrestore(&iovad
->iova_rbtree_lock
, flags
);
298 * free_iova - finds and frees the iova for a given pfn
299 * @iovad: - iova domain in question.
300 * @pfn: - pfn that is allocated previously
301 * This functions finds an iova for a given pfn and then
302 * frees the iova from that domain.
305 free_iova(struct iova_domain
*iovad
, unsigned long pfn
)
307 struct iova
*iova
= find_iova(iovad
, pfn
);
309 __free_iova(iovad
, iova
);
314 * put_iova_domain - destroys the iova doamin
315 * @iovad: - iova domain in question.
316 * All the iova's in that domain are destroyed.
318 void put_iova_domain(struct iova_domain
*iovad
)
320 struct rb_node
*node
;
323 spin_lock_irqsave(&iovad
->iova_rbtree_lock
, flags
);
324 node
= rb_first(&iovad
->rbroot
);
326 struct iova
*iova
= container_of(node
, struct iova
, node
);
327 rb_erase(node
, &iovad
->rbroot
);
329 node
= rb_first(&iovad
->rbroot
);
331 spin_unlock_irqrestore(&iovad
->iova_rbtree_lock
, flags
);
335 __is_range_overlap(struct rb_node
*node
,
336 unsigned long pfn_lo
, unsigned long pfn_hi
)
338 struct iova
*iova
= container_of(node
, struct iova
, node
);
340 if ((pfn_lo
<= iova
->pfn_hi
) && (pfn_hi
>= iova
->pfn_lo
))
346 __insert_new_range(struct iova_domain
*iovad
,
347 unsigned long pfn_lo
, unsigned long pfn_hi
)
351 iova
= alloc_iova_mem();
355 iova
->pfn_hi
= pfn_hi
;
356 iova
->pfn_lo
= pfn_lo
;
357 iova_insert_rbtree(&iovad
->rbroot
, iova
);
362 __adjust_overlap_range(struct iova
*iova
,
363 unsigned long *pfn_lo
, unsigned long *pfn_hi
)
365 if (*pfn_lo
< iova
->pfn_lo
)
366 iova
->pfn_lo
= *pfn_lo
;
367 if (*pfn_hi
> iova
->pfn_hi
)
368 *pfn_lo
= iova
->pfn_hi
+ 1;
372 * reserve_iova - reserves an iova in the given range
373 * @iovad: - iova domain pointer
374 * @pfn_lo: - lower page frame address
375 * @pfn_hi:- higher pfn adderss
376 * This function allocates reserves the address range from pfn_lo to pfn_hi so
377 * that this address is not dished out as part of alloc_iova.
380 reserve_iova(struct iova_domain
*iovad
,
381 unsigned long pfn_lo
, unsigned long pfn_hi
)
383 struct rb_node
*node
;
386 unsigned int overlap
= 0;
388 spin_lock_irqsave(&iovad
->iova_rbtree_lock
, flags
);
389 for (node
= rb_first(&iovad
->rbroot
); node
; node
= rb_next(node
)) {
390 if (__is_range_overlap(node
, pfn_lo
, pfn_hi
)) {
391 iova
= container_of(node
, struct iova
, node
);
392 __adjust_overlap_range(iova
, &pfn_lo
, &pfn_hi
);
393 if ((pfn_lo
>= iova
->pfn_lo
) &&
394 (pfn_hi
<= iova
->pfn_hi
))
402 /* We are here either because this is the first reserver node
403 * or need to insert remaining non overlap addr range
405 iova
= __insert_new_range(iovad
, pfn_lo
, pfn_hi
);
408 spin_unlock_irqrestore(&iovad
->iova_rbtree_lock
, flags
);
413 * copy_reserved_iova - copies the reserved between domains
414 * @from: - source doamin from where to copy
415 * @to: - destination domin where to copy
416 * This function copies reserved iova's from one doamin to
420 copy_reserved_iova(struct iova_domain
*from
, struct iova_domain
*to
)
423 struct rb_node
*node
;
425 spin_lock_irqsave(&from
->iova_rbtree_lock
, flags
);
426 for (node
= rb_first(&from
->rbroot
); node
; node
= rb_next(node
)) {
427 struct iova
*iova
= container_of(node
, struct iova
, node
);
428 struct iova
*new_iova
;
429 new_iova
= reserve_iova(to
, iova
->pfn_lo
, iova
->pfn_hi
);
431 printk(KERN_ERR
"Reserve iova range %lx@%lx failed\n",
432 iova
->pfn_lo
, iova
->pfn_lo
);
434 spin_unlock_irqrestore(&from
->iova_rbtree_lock
, flags
);
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