/*
* 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) {
struct rb_node *node = rb_next(&free->node);
struct iova *iova = container_of(node, struct iova, node);
/* only cache if it's below 32bit pfn */
if (node && iova->pfn_lo < iovad->dma_32bit_pfn)
iovad->cached32_node = node;
else
iovad->cached32_node = NULL;
}
}
/* 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 because 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);
}
