1/* 2 * Copyright �� 2006-2009, Intel Corporation. 3 * 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. 7 * 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 11 * more details. 12 * 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. 16 * 17 * Author: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> 18 */ 19 20#include <linux/iova.h> 21 22void 23init_iova_domain(struct iova_domain *iovad, unsigned long pfn_32bit) 24{ 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; 29} 30 31static struct rb_node * 32__get_cached_rbnode(struct iova_domain *iovad, unsigned long *limit_pfn) 33{ 34 if ((*limit_pfn != iovad->dma_32bit_pfn) || 35 (iovad->cached32_node == NULL)) 36 return rb_last(&iovad->rbroot); 37 else { 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; 42 return prev_node; 43 } 44} 45 46static void 47__cached_rbnode_insert_update(struct iova_domain *iovad, 48 unsigned long limit_pfn, struct iova *new) 49{ 50 if (limit_pfn != iovad->dma_32bit_pfn) 51 return; 52 iovad->cached32_node = &new->node; 53} 54 55static void 56__cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free) 57{ 58 struct iova *cached_iova; 59 struct rb_node *curr; 60 61 if (!iovad->cached32_node) 62 return; 63 curr = iovad->cached32_node; 64 cached_iova = container_of(curr, struct iova, node); 65 66 if (free->pfn_lo >= cached_iova->pfn_lo) 67 iovad->cached32_node = rb_next(&free->node); 68} 69 70/* Computes the padding size required, to make the 71 * the start address naturally aligned on its size 72 */ 73static int 74iova_get_pad_size(int size, unsigned int limit_pfn) 75{ 76 unsigned int pad_size = 0; 77 unsigned int order = ilog2(size); 78 79 if (order) 80 pad_size = (limit_pfn + 1) % (1 << order); 81 82 return pad_size; 83} 84 85static int __alloc_and_insert_iova_range(struct iova_domain *iovad, 86 unsigned long size, unsigned long limit_pfn, 87 struct iova *new, bool size_aligned) 88{ 89 struct rb_node *prev, *curr = NULL; 90 unsigned long flags; 91 unsigned long saved_pfn; 92 unsigned int pad_size = 0; 93 94 /* Walk the tree backwards */ 95 spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); 96 saved_pfn = limit_pfn; 97 curr = __get_cached_rbnode(iovad, &limit_pfn); 98 prev = curr; 99 while (curr) { 100 struct iova *curr_iova = container_of(curr, struct iova, node); 101 102 if (limit_pfn < curr_iova->pfn_lo) 103 goto move_left; 104 else if (limit_pfn < curr_iova->pfn_hi) 105 goto adjust_limit_pfn; 106 else { 107 if (size_aligned) 108 pad_size = iova_get_pad_size(size, limit_pfn); 109 if ((curr_iova->pfn_hi + size + pad_size) <= limit_pfn) 110 break; /* found a free slot */ 111 } 112adjust_limit_pfn: 113 limit_pfn = curr_iova->pfn_lo - 1; 114move_left: 115 prev = curr; 116 curr = rb_prev(curr); 117 } 118 119 if (!curr) { 120 if (size_aligned) 121 pad_size = iova_get_pad_size(size, limit_pfn); 122 if ((IOVA_START_PFN + size + pad_size) > limit_pfn) { 123 spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); 124 return -ENOMEM; 125 } 126 } 127 128 /* pfn_lo will point to size aligned address if size_aligned is set */ 129 new->pfn_lo = limit_pfn - (size + pad_size) + 1; 130 new->pfn_hi = new->pfn_lo + size - 1; 131 132 /* Insert the new_iova into domain rbtree by holding writer lock */ 133 /* Add new node and rebalance tree. */ 134 { 135 struct rb_node **entry, *parent = NULL; 136 137 /* If we have 'prev', it's a valid place to start the 138 insertion. Otherwise, start from the root. */ 139 if (prev) 140 entry = &prev; 141 else 142 entry = &iovad->rbroot.rb_node; 143 144 /* Figure out where to put new node */ 145 while (*entry) { 146 struct iova *this = container_of(*entry, 147 struct iova, node); 148 parent = *entry; 149 150 if (new->pfn_lo < this->pfn_lo) 151 entry = &((*entry)->rb_left); 152 else if (new->pfn_lo > this->pfn_lo) 153 entry = &((*entry)->rb_right); 154 else 155 BUG(); /* this should not happen */ 156 } 157 158 /* Add new node and rebalance tree. */ 159 rb_link_node(&new->node, parent, entry); 160 rb_insert_color(&new->node, &iovad->rbroot); 161 } 162 __cached_rbnode_insert_update(iovad, saved_pfn, new); 163 164 spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); 165 166 167 return 0; 168} 169 170static void 171iova_insert_rbtree(struct rb_root *root, struct iova *iova) 172{ 173 struct rb_node **new = &(root->rb_node), *parent = NULL; 174 /* Figure out where to put new node */ 175 while (*new) { 176 struct iova *this = container_of(*new, struct iova, node); 177 parent = *new; 178 179 if (iova->pfn_lo < this->pfn_lo) 180 new = &((*new)->rb_left); 181 else if (iova->pfn_lo > this->pfn_lo) 182 new = &((*new)->rb_right); 183 else 184 BUG(); /* this should not happen */ 185 } 186 /* Add new node and rebalance tree. */ 187 rb_link_node(&iova->node, parent, new); 188 rb_insert_color(&iova->node, root); 189} 190 191/** 192 * alloc_iova - allocates an iova 193 * @iovad - iova domain in question 194 * @size - size of page frames to allocate 195 * @limit_pfn - max limit address 196 * @size_aligned - set if size_aligned address range is required 197 * This function allocates an iova in the range limit_pfn to IOVA_START_PFN 198 * looking from limit_pfn instead from IOVA_START_PFN. If the size_aligned 199 * flag is set then the allocated address iova->pfn_lo will be naturally 200 * aligned on roundup_power_of_two(size). 201 */ 202struct iova * 203alloc_iova(struct iova_domain *iovad, unsigned long size, 204 unsigned long limit_pfn, 205 bool size_aligned) 206{ 207 struct iova *new_iova; 208 int ret; 209 210 new_iova = alloc_iova_mem(); 211 if (!new_iova) 212 return NULL; 213 214 /* If size aligned is set then round the size to 215 * to next power of two. 216 */ 217 if (size_aligned) 218 size = __roundup_pow_of_two(size); 219 220 ret = __alloc_and_insert_iova_range(iovad, size, limit_pfn, 221 new_iova, size_aligned); 222 223 if (ret) { 224 free_iova_mem(new_iova); 225 return NULL; 226 } 227 228 return new_iova; 229} 230 231/** 232 * find_iova - find's an iova for a given pfn 233 * @iovad - iova domain in question. 234 * pfn - page frame number 235 * This function finds and returns an iova belonging to the 236 * given doamin which matches the given pfn. 237 */ 238struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn) 239{ 240 unsigned long flags; 241 struct rb_node *node; 242 243 /* Take the lock so that no other thread is manipulating the rbtree */ 244 spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); 245 node = iovad->rbroot.rb_node; 246 while (node) { 247 struct iova *iova = container_of(node, struct iova, node); 248 249 /* If pfn falls within iova's range, return iova */ 250 if ((pfn >= iova->pfn_lo) && (pfn <= iova->pfn_hi)) { 251 spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); 252 /* We are not holding the lock while this iova 253 * is referenced by the caller as the same thread 254 * which called this function also calls __free_iova() 255 * and it is by desing that only one thread can possibly 256 * reference a particular iova and hence no conflict. 257 */ 258 return iova; 259 } 260 261 if (pfn < iova->pfn_lo) 262 node = node->rb_left; 263 else if (pfn > iova->pfn_lo) 264 node = node->rb_right; 265 } 266 267 spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); 268 return NULL; 269} 270 271/** 272 * __free_iova - frees the given iova 273 * @iovad: iova domain in question. 274 * @iova: iova in question. 275 * Frees the given iova belonging to the giving domain 276 */ 277void 278__free_iova(struct iova_domain *iovad, struct iova *iova) 279{ 280 unsigned long flags; 281 282 spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); 283 __cached_rbnode_delete_update(iovad, iova); 284 rb_erase(&iova->node, &iovad->rbroot); 285 spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); 286 free_iova_mem(iova); 287} 288 289/** 290 * free_iova - finds and frees the iova for a given pfn 291 * @iovad: - iova domain in question. 292 * @pfn: - pfn that is allocated previously 293 * This functions finds an iova for a given pfn and then 294 * frees the iova from that domain. 295 */ 296void 297free_iova(struct iova_domain *iovad, unsigned long pfn) 298{ 299 struct iova *iova = find_iova(iovad, pfn); 300 if (iova) 301 __free_iova(iovad, iova); 302 303} 304 305/** 306 * put_iova_domain - destroys the iova doamin 307 * @iovad: - iova domain in question. 308 * All the iova's in that domain are destroyed. 309 */ 310void put_iova_domain(struct iova_domain *iovad) 311{ 312 struct rb_node *node; 313 unsigned long flags; 314 315 spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); 316 node = rb_first(&iovad->rbroot); 317 while (node) { 318 struct iova *iova = container_of(node, struct iova, node); 319 rb_erase(node, &iovad->rbroot); 320 free_iova_mem(iova); 321 node = rb_first(&iovad->rbroot); 322 } 323 spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); 324} 325 326static int 327__is_range_overlap(struct rb_node *node, 328 unsigned long pfn_lo, unsigned long pfn_hi) 329{ 330 struct iova *iova = container_of(node, struct iova, node); 331 332 if ((pfn_lo <= iova->pfn_hi) && (pfn_hi >= iova->pfn_lo)) 333 return 1; 334 return 0; 335} 336 337static struct iova * 338__insert_new_range(struct iova_domain *iovad, 339 unsigned long pfn_lo, unsigned long pfn_hi) 340{ 341 struct iova *iova; 342 343 iova = alloc_iova_mem(); 344 if (!iova) 345 return iova; 346 347 iova->pfn_hi = pfn_hi; 348 iova->pfn_lo = pfn_lo; 349 iova_insert_rbtree(&iovad->rbroot, iova); 350 return iova; 351} 352 353static void 354__adjust_overlap_range(struct iova *iova, 355 unsigned long *pfn_lo, unsigned long *pfn_hi) 356{ 357 if (*pfn_lo < iova->pfn_lo) 358 iova->pfn_lo = *pfn_lo; 359 if (*pfn_hi > iova->pfn_hi) 360 *pfn_lo = iova->pfn_hi + 1; 361} 362 363/** 364 * reserve_iova - reserves an iova in the given range 365 * @iovad: - iova domain pointer 366 * @pfn_lo: - lower page frame address 367 * @pfn_hi:- higher pfn adderss 368 * This function allocates reserves the address range from pfn_lo to pfn_hi so 369 * that this address is not dished out as part of alloc_iova. 370 */ 371struct iova * 372reserve_iova(struct iova_domain *iovad, 373 unsigned long pfn_lo, unsigned long pfn_hi) 374{ 375 struct rb_node *node; 376 unsigned long flags; 377 struct iova *iova; 378 unsigned int overlap = 0; 379 380 spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); 381 for (node = rb_first(&iovad->rbroot); node; node = rb_next(node)) { 382 if (__is_range_overlap(node, pfn_lo, pfn_hi)) { 383 iova = container_of(node, struct iova, node); 384 __adjust_overlap_range(iova, &pfn_lo, &pfn_hi); 385 if ((pfn_lo >= iova->pfn_lo) && 386 (pfn_hi <= iova->pfn_hi)) 387 goto finish; 388 overlap = 1; 389 390 } else if (overlap) 391 break; 392 } 393 394 /* We are here either becasue this is the first reserver node 395 * or need to insert remaining non overlap addr range 396 */ 397 iova = __insert_new_range(iovad, pfn_lo, pfn_hi); 398finish: 399 400 spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); 401 return iova; 402} 403 404/** 405 * copy_reserved_iova - copies the reserved between domains 406 * @from: - source doamin from where to copy 407 * @to: - destination domin where to copy 408 * This function copies reserved iova's from one doamin to 409 * other. 410 */ 411void 412copy_reserved_iova(struct iova_domain *from, struct iova_domain *to) 413{ 414 unsigned long flags; 415 struct rb_node *node; 416 417 spin_lock_irqsave(&from->iova_rbtree_lock, flags); 418 for (node = rb_first(&from->rbroot); node; node = rb_next(node)) { 419 struct iova *iova = container_of(node, struct iova, node); 420 struct iova *new_iova; 421 new_iova = reserve_iova(to, iova->pfn_lo, iova->pfn_hi); 422 if (!new_iova) 423 printk(KERN_ERR "Reserve iova range %lx@%lx failed\n", 424 iova->pfn_lo, iova->pfn_lo); 425 } 426 spin_unlock_irqrestore(&from->iova_rbtree_lock, flags); 427} 428