--- /dev/null
+/*
+ * 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);
+}
projects / linux-2.6 / commitdiff