diff options
Diffstat (limited to 'drivers/pci/iova.c')
| -rw-r--r-- | drivers/pci/iova.c | 357 |
1 files changed, 357 insertions, 0 deletions
diff --git a/drivers/pci/iova.c b/drivers/pci/iova.c new file mode 100644 index 000000000000..717fafaa7e02 --- /dev/null +++ b/drivers/pci/iova.c @@ -0,0 +1,357 @@ +/* + * Copyright (c) 2006, Intel Corporation. + * + * This file is released under the GPLv2. + * + * Copyright (C) 2006 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> + */ + +#include "iova.h" + +void +init_iova_domain(struct iova_domain *iovad) +{ + spin_lock_init(&iovad->iova_alloc_lock); + spin_lock_init(&iovad->iova_rbtree_lock); + iovad->rbroot = RB_ROOT; + iovad->cached32_node = NULL; + +} + +static struct rb_node * +__get_cached_rbnode(struct iova_domain *iovad, unsigned long *limit_pfn) +{ + if ((*limit_pfn != 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 != 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); +} + +static int __alloc_iova_range(struct iova_domain *iovad, + unsigned long size, unsigned long limit_pfn, struct iova *new) +{ + struct rb_node *curr = NULL; + unsigned long flags; + unsigned long saved_pfn; + + /* Walk the tree backwards */ + spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); + saved_pfn = limit_pfn; + curr = __get_cached_rbnode(iovad, &limit_pfn); + while (curr) { + struct iova *curr_iova = container_of(curr, struct iova, node); + if (limit_pfn < curr_iova->pfn_lo) + goto move_left; + if (limit_pfn < curr_iova->pfn_hi) + goto adjust_limit_pfn; + if ((curr_iova->pfn_hi + size) <= limit_pfn) + break; /* found a free slot */ +adjust_limit_pfn: + limit_pfn = curr_iova->pfn_lo - 1; +move_left: + curr = rb_prev(curr); + } + + if ((!curr) && !(IOVA_START_PFN + size <= limit_pfn)) { + spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); + return -ENOMEM; + } + new->pfn_hi = limit_pfn; + new->pfn_lo = limit_pfn - size + 1; + + 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 + * This function allocates an iova in the range limit_pfn to IOVA_START_PFN + * looking from limit_pfn instead from IOVA_START_PFN. + */ +struct iova * +alloc_iova(struct iova_domain *iovad, unsigned long size, + unsigned long limit_pfn) +{ + unsigned long flags; + struct iova *new_iova; + int ret; + + new_iova = alloc_iova_mem(); + if (!new_iova) + return NULL; + + spin_lock_irqsave(&iovad->iova_alloc_lock, flags); + ret = __alloc_iova_range(iovad, size, limit_pfn, new_iova); + + if (ret) { + spin_unlock_irqrestore(&iovad->iova_alloc_lock, flags); + free_iova_mem(new_iova); + return NULL; + } + + /* Insert the new_iova into domain rbtree by holding writer lock */ + spin_lock(&iovad->iova_rbtree_lock); + iova_insert_rbtree(&iovad->rbroot, new_iova); + __cached_rbnode_insert_update(iovad, limit_pfn, new_iova); + spin_unlock(&iovad->iova_rbtree_lock); + + spin_unlock_irqrestore(&iovad->iova_alloc_lock, flags); + + 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_alloc_lock, flags); + spin_lock(&iovad->iova_rbtree_lock); + 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(&iovad->iova_rbtree_lock); + spin_unlock_irqrestore(&iovad->iova_alloc_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_alloc_lock, flags); + spin_lock(&from->iova_rbtree_lock); + 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(&from->iova_rbtree_lock); + spin_unlock_irqrestore(&from->iova_alloc_lock, flags); +} |