/* * Copyright © 2006-2009, Intel Corporation. * * This program is free software; you can redistribute it and/or modify it * under the terms and conditions of the GNU General Public License, * version 2, as published by the Free Software Foundation. * * This program is distributed in the hope it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for * more details. * * You should have received a copy of the GNU General Public License along with * this program; if not, write to the Free Software Foundation, Inc., 59 Temple * Place - Suite 330, Boston, MA 02111-1307 USA. * * Author: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> */ #include <linux/iova.h> void init_iova_domain(struct iova_domain *iovad, unsigned long pfn_32bit) { spin_lock_init(&iovad->iova_rbtree_lock); iovad->rbroot = RB_ROOT; iovad->cached32_node = NULL; iovad->dma_32bit_pfn = pfn_32bit; } static struct rb_node * __get_cached_rbnode(struct iova_domain *iovad, unsigned long *limit_pfn) { if ((*limit_pfn != iovad->dma_32bit_pfn) || (iovad->cached32_node == NULL)) return rb_last(&iovad->rbroot); else { struct rb_node *prev_node = rb_prev(iovad->cached32_node); struct iova *curr_iova = container_of(iovad->cached32_node, struct iova, node); *limit_pfn = curr_iova->pfn_lo - 1; return prev_node; } } static void __cached_rbnode_insert_update(struct iova_domain *iovad, unsigned long limit_pfn, struct iova *new) { if (limit_pfn != iovad->dma_32bit_pfn) return; iovad->cached32_node = &new->node; } static void __cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free) { struct iova *cached_iova; struct rb_node *curr; if (!iovad->cached32_node) return; curr = iovad->cached32_node; cached_iova = container_of(curr, struct iova, node); if (free->pfn_lo >= cached_iova->pfn_lo) iovad->cached32_node = rb_next(&free->node); } /* Computes the padding size required, to make the * the start address naturally aligned on its size */ static int iova_get_pad_size(int size, unsigned int limit_pfn) { unsigned int pad_size = 0; unsigned int order = ilog2(size); if (order) pad_size = (limit_pfn + 1) % (1 << order); return pad_size; } static int __alloc_and_insert_iova_range(struct iova_domain *iovad, unsigned long size, unsigned long limit_pfn, struct iova *new, bool size_aligned) { struct rb_node *prev, *curr = NULL; unsigned long flags; unsigned long saved_pfn; unsigned int pad_size = 0; /* Walk the tree backwards */ spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); saved_pfn = limit_pfn; curr = __get_cached_rbnode(iovad, &limit_pfn); prev = curr; while (curr) { struct iova *curr_iova = container_of(curr, struct iova, node); if (limit_pfn < curr_iova->pfn_lo) goto move_left; else if (limit_pfn < curr_iova->pfn_hi) goto adjust_limit_pfn; else { if (size_aligned) pad_size = iova_get_pad_size(size, limit_pfn); if ((curr_iova->pfn_hi + size + pad_size) <= limit_pfn) break; /* found a free slot */ } adjust_limit_pfn: limit_pfn = curr_iova->pfn_lo - 1; move_left: prev = curr; curr = rb_prev(curr); } if (!curr) { if (size_aligned) pad_size = iova_get_pad_size(size, limit_pfn); if ((IOVA_START_PFN + size + pad_size) > limit_pfn) { spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); return -ENOMEM; } } /* pfn_lo will point to size aligned address if size_aligned is set */ new->pfn_lo = limit_pfn - (size + pad_size) + 1; new->pfn_hi = new->pfn_lo + size - 1; /* Insert the new_iova into domain rbtree by holding writer lock */ /* Add new node and rebalance tree. */ { struct rb_node **entry, *parent = NULL; /* If we have 'prev', it's a valid place to start the insertion. Otherwise, start from the root. */ if (prev) entry = &prev; else entry = &iovad->rbroot.rb_node; /* Figure out where to put new node */ while (*entry) { struct iova *this = container_of(*entry, struct iova, node); parent = *entry; if (new->pfn_lo < this->pfn_lo) entry = &((*entry)->rb_left); else if (new->pfn_lo > this->pfn_lo) entry = &((*entry)->rb_right); else BUG(); /* this should not happen */ } /* Add new node and rebalance tree. */ rb_link_node(&new->node, parent, entry); rb_insert_color(&new->node, &iovad->rbroot); } __cached_rbnode_insert_update(iovad, saved_pfn, new); spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); return 0; } static void iova_insert_rbtree(struct rb_root *root, struct iova *iova) { struct rb_node **new = &(root->rb_node), *parent = NULL; /* Figure out where to put new node */ while (*new) { struct iova *this = container_of(*new, struct iova, node); parent = *new; if (iova->pfn_lo < this->pfn_lo) new = &((*new)->rb_left); else if (iova->pfn_lo > this->pfn_lo) new = &((*new)->rb_right); else BUG(); /* this should not happen */ } /* Add new node and rebalance tree. */ rb_link_node(&iova->node, parent, new); rb_insert_color(&iova->node, root); } /** * alloc_iova - allocates an iova * @iovad - iova domain in question * @size - size of page frames to allocate * @limit_pfn - max limit address * @size_aligned - set if size_aligned address range is required * This function allocates an iova in the range limit_pfn to IOVA_START_PFN * looking from limit_pfn instead from IOVA_START_PFN. If the size_aligned * flag is set then the allocated address iova->pfn_lo will be naturally * aligned on roundup_power_of_two(size). */ struct iova * alloc_iova(struct iova_domain *iovad, unsigned long size, unsigned long limit_pfn, bool size_aligned) { struct iova *new_iova; int ret; new_iova = alloc_iova_mem(); if (!new_iova) return NULL; /* If size aligned is set then round the size to * to next power of two. */ if (size_aligned) size = __roundup_pow_of_two(size); ret = __alloc_and_insert_iova_range(iovad, size, limit_pfn, new_iova, size_aligned); if (ret) { free_iova_mem(new_iova); return NULL; } return new_iova; } /** * find_iova - find's an iova for a given pfn * @iovad - iova domain in question. * pfn - page frame number * This function finds and returns an iova belonging to the * given doamin which matches the given pfn. */ struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn) { unsigned long flags; struct rb_node *node; /* Take the lock so that no other thread is manipulating the rbtree */ spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); node = iovad->rbroot.rb_node; while (node) { struct iova *iova = container_of(node, struct iova, node); /* If pfn falls within iova's range, return iova */ if ((pfn >= iova->pfn_lo) && (pfn <= iova->pfn_hi)) { spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); /* We are not holding the lock while this iova * is referenced by the caller as the same thread * which called this function also calls __free_iova() * and it is by desing that only one thread can possibly * reference a particular iova and hence no conflict. */ return iova; } if (pfn < iova->pfn_lo) node = node->rb_left; else if (pfn > iova->pfn_lo) node = node->rb_right; } spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); return NULL; } /** * __free_iova - frees the given iova * @iovad: iova domain in question. * @iova: iova in question. * Frees the given iova belonging to the giving domain */ void __free_iova(struct iova_domain *iovad, struct iova *iova) { unsigned long flags; spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); __cached_rbnode_delete_update(iovad, iova); rb_erase(&iova->node, &iovad->rbroot); spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); free_iova_mem(iova); } /** * free_iova - finds and frees the iova for a given pfn * @iovad: - iova domain in question. * @pfn: - pfn that is allocated previously * This functions finds an iova for a given pfn and then * frees the iova from that domain. */ void free_iova(struct iova_domain *iovad, unsigned long pfn) { struct iova *iova = find_iova(iovad, pfn); if (iova) __free_iova(iovad, iova); } /** * put_iova_domain - destroys the iova doamin * @iovad: - iova domain in question. * All the iova's in that domain are destroyed. */ void put_iova_domain(struct iova_domain *iovad) { struct rb_node *node; unsigned long flags; spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); node = rb_first(&iovad->rbroot); while (node) { struct iova *iova = container_of(node, struct iova, node); rb_erase(node, &iovad->rbroot); free_iova_mem(iova); node = rb_first(&iovad->rbroot); } spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); } static int __is_range_overlap(struct rb_node *node, unsigned long pfn_lo, unsigned long pfn_hi) { struct iova *iova = container_of(node, struct iova, node); if ((pfn_lo <= iova->pfn_hi) && (pfn_hi >= iova->pfn_lo)) return 1; return 0; } static struct iova * __insert_new_range(struct iova_domain *iovad, unsigned long pfn_lo, unsigned long pfn_hi) { struct iova *iova; iova = alloc_iova_mem(); if (!iova) return iova; iova->pfn_hi = pfn_hi; iova->pfn_lo = pfn_lo; iova_insert_rbtree(&iovad->rbroot, iova); return iova; } static void __adjust_overlap_range(struct iova *iova, unsigned long *pfn_lo, unsigned long *pfn_hi) { if (*pfn_lo < iova->pfn_lo) iova->pfn_lo = *pfn_lo; if (*pfn_hi > iova->pfn_hi) *pfn_lo = iova->pfn_hi + 1; } /** * reserve_iova - reserves an iova in the given range * @iovad: - iova domain pointer * @pfn_lo: - lower page frame address * @pfn_hi:- higher pfn adderss * This function allocates reserves the address range from pfn_lo to pfn_hi so * that this address is not dished out as part of alloc_iova. */ struct iova * reserve_iova(struct iova_domain *iovad, unsigned long pfn_lo, unsigned long pfn_hi) { struct rb_node *node; unsigned long flags; struct iova *iova; unsigned int overlap = 0; spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); for (node = rb_first(&iovad->rbroot); node; node = rb_next(node)) { if (__is_range_overlap(node, pfn_lo, pfn_hi)) { iova = container_of(node, struct iova, node); __adjust_overlap_range(iova, &pfn_lo, &pfn_hi); if ((pfn_lo >= iova->pfn_lo) && (pfn_hi <= iova->pfn_hi)) goto finish; overlap = 1; } else if (overlap) break; } /* We are here either becasue this is the first reserver node * or need to insert remaining non overlap addr range */ iova = __insert_new_range(iovad, pfn_lo, pfn_hi); finish: spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); return iova; } /** * copy_reserved_iova - copies the reserved between domains * @from: - source doamin from where to copy * @to: - destination domin where to copy * This function copies reserved iova's from one doamin to * other. */ void copy_reserved_iova(struct iova_domain *from, struct iova_domain *to) { unsigned long flags; struct rb_node *node; spin_lock_irqsave(&from->iova_rbtree_lock, flags); for (node = rb_first(&from->rbroot); node; node = rb_next(node)) { struct iova *iova = container_of(node, struct iova, node); struct iova *new_iova; new_iova = reserve_iova(to, iova->pfn_lo, iova->pfn_hi); if (!new_iova) printk(KERN_ERR "Reserve iova range %lx@%lx failed\n", iova->pfn_lo, iova->pfn_lo); } spin_unlock_irqrestore(&from->iova_rbtree_lock, flags); }