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DEFINITIONS
This source file includes following definitions.
- r_next
- r_start
- r_stop
- r_show
- ioports_open
- iomem_open
- ioresources_init
- __request_resource
- __release_resource
- request_resource
- release_resource
- find_next_system_ram
- walk_memory_resource
- find_resource
- allocate_resource
- __insert_resource
- insert_resource
- insert_resource_expand_to_fit
- adjust_resource
- __reserve_region_with_split
- reserve_region_with_split
- resource_alignment
- __request_region
- __check_region
- __release_region
- devm_region_release
- devm_region_match
- __devm_request_region
- __devm_release_region
- reserve_setup
/*
* linux/kernel/resource.c
*
* Copyright (C) 1999 Linus Torvalds
* Copyright (C) 1999 Martin Mares <mj@ucw.cz>
*
* Arbitrary resource management.
*/
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/fs.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/device.h>
#include <asm/io.h>
struct resource ioport_resource = {
.name = "PCI IO",
.start = 0,
.end = IO_SPACE_LIMIT,
.flags = IORESOURCE_IO,
};
EXPORT_SYMBOL(ioport_resource);
struct resource iomem_resource = {
.name = "PCI mem",
.start = 0,
.end = -1,
.flags = IORESOURCE_MEM,
};
EXPORT_SYMBOL(iomem_resource);
static DEFINE_RWLOCK(resource_lock);
#ifdef CONFIG_PROC_FS
enum { MAX_IORES_LEVEL = 5 };
static void *r_next(struct seq_file *m, void *v, loff_t *pos)
{
struct resource *p = v;
(*pos)++;
if (p->child)
return p->child;
while (!p->sibling && p->parent)
p = p->parent;
return p->sibling;
}
static void *r_start(struct seq_file *m, loff_t *pos)
__acquires(resource_lock)
{
struct resource *p = m->private;
loff_t l = 0;
read_lock(&resource_lock);
for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
;
return p;
}
static void r_stop(struct seq_file *m, void *v)
__releases(resource_lock)
{
read_unlock(&resource_lock);
}
static int r_show(struct seq_file *m, void *v)
{
struct resource *root = m->private;
struct resource *r = v, *p;
int width = root->end < 0x10000 ? 4 : 8;
int depth;
for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
if (p->parent == root)
break;
seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
depth * 2, "",
width, (unsigned long long) r->start,
width, (unsigned long long) r->end,
r->name ? r->name : "<BAD>");
return 0;
}
static const struct seq_operations resource_op = {
.start = r_start,
.next = r_next,
.stop = r_stop,
.show = r_show,
};
static int ioports_open(struct inode *inode, struct file *file)
{
int res = seq_open(file, &resource_op);
if (!res) {
struct seq_file *m = file->private_data;
m->private = &ioport_resource;
}
return res;
}
static int iomem_open(struct inode *inode, struct file *file)
{
int res = seq_open(file, &resource_op);
if (!res) {
struct seq_file *m = file->private_data;
m->private = &iomem_resource;
}
return res;
}
static const struct file_operations proc_ioports_operations = {
.open = ioports_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static const struct file_operations proc_iomem_operations = {
.open = iomem_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static int __init ioresources_init(void)
{
proc_create("ioports", 0, NULL, &proc_ioports_operations);
proc_create("iomem", 0, NULL, &proc_iomem_operations);
return 0;
}
__initcall(ioresources_init);
#endif /* CONFIG_PROC_FS */
/* Return the conflict entry if you can't request it */
static struct resource * __request_resource(struct resource *root, struct resource *new)
{
resource_size_t start = new->start;
resource_size_t end = new->end;
struct resource *tmp, **p;
if (end < start)
return root;
if (start < root->start)
return root;
if (end > root->end)
return root;
p = &root->child;
for (;;) {
tmp = *p;
if (!tmp || tmp->start > end) {
new->sibling = tmp;
*p = new;
new->parent = root;
return NULL;
}
p = &tmp->sibling;
if (tmp->end < start)
continue;
return tmp;
}
}
static int __release_resource(struct resource *old)
{
struct resource *tmp, **p;
p = &old->parent->child;
for (;;) {
tmp = *p;
if (!tmp)
break;
if (tmp == old) {
*p = tmp->sibling;
old->parent = NULL;
return 0;
}
p = &tmp->sibling;
}
return -EINVAL;
}
/**
* request_resource - request and reserve an I/O or memory resource
* @root: root resource descriptor
* @new: resource descriptor desired by caller
*
* Returns 0 for success, negative error code on error.
*/
int request_resource(struct resource *root, struct resource *new)
{
struct resource *conflict;
write_lock(&resource_lock);
conflict = __request_resource(root, new);
write_unlock(&resource_lock);
return conflict ? -EBUSY : 0;
}
EXPORT_SYMBOL(request_resource);
/**
* release_resource - release a previously reserved resource
* @old: resource pointer
*/
int release_resource(struct resource *old)
{
int retval;
write_lock(&resource_lock);
retval = __release_resource(old);
write_unlock(&resource_lock);
return retval;
}
EXPORT_SYMBOL(release_resource);
#if defined(CONFIG_MEMORY_HOTPLUG) && !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
/*
* Finds the lowest memory reosurce exists within [res->start.res->end)
* the caller must specify res->start, res->end, res->flags.
* If found, returns 0, res is overwritten, if not found, returns -1.
*/
static int find_next_system_ram(struct resource *res)
{
resource_size_t start, end;
struct resource *p;
BUG_ON(!res);
start = res->start;
end = res->end;
BUG_ON(start >= end);
read_lock(&resource_lock);
for (p = iomem_resource.child; p ; p = p->sibling) {
/* system ram is just marked as IORESOURCE_MEM */
if (p->flags != res->flags)
continue;
if (p->start > end) {
p = NULL;
break;
}
if ((p->end >= start) && (p->start < end))
break;
}
read_unlock(&resource_lock);
if (!p)
return -1;
/* copy data */
if (res->start < p->start)
res->start = p->start;
if (res->end > p->end)
res->end = p->end;
return 0;
}
int
walk_memory_resource(unsigned long start_pfn, unsigned long nr_pages, void *arg,
int (*func)(unsigned long, unsigned long, void *))
{
struct resource res;
unsigned long pfn, len;
u64 orig_end;
int ret = -1;
res.start = (u64) start_pfn << PAGE_SHIFT;
res.end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
orig_end = res.end;
while ((res.start < res.end) && (find_next_system_ram(&res) >= 0)) {
pfn = (unsigned long)(res.start >> PAGE_SHIFT);
len = (unsigned long)((res.end + 1 - res.start) >> PAGE_SHIFT);
ret = (*func)(pfn, len, arg);
if (ret)
break;
res.start = res.end + 1;
res.end = orig_end;
}
return ret;
}
#endif
/*
* Find empty slot in the resource tree given range and alignment.
*/
static int find_resource(struct resource *root, struct resource *new,
resource_size_t size, resource_size_t min,
resource_size_t max, resource_size_t align,
void (*alignf)(void *, struct resource *,
resource_size_t, resource_size_t),
void *alignf_data)
{
struct resource *this = root->child;
new->start = root->start;
/*
* Skip past an allocated resource that starts at 0, since the assignment
* of this->start - 1 to new->end below would cause an underflow.
*/
if (this && this->start == 0) {
new->start = this->end + 1;
this = this->sibling;
}
for(;;) {
if (this)
new->end = this->start - 1;
else
new->end = root->end;
if (new->start < min)
new->start = min;
if (new->end > max)
new->end = max;
new->start = ALIGN(new->start, align);
if (alignf)
alignf(alignf_data, new, size, align);
if (new->start < new->end && new->end - new->start >= size - 1) {
new->end = new->start + size - 1;
return 0;
}
if (!this)
break;
new->start = this->end + 1;
this = this->sibling;
}
return -EBUSY;
}
/**
* allocate_resource - allocate empty slot in the resource tree given range & alignment
* @root: root resource descriptor
* @new: resource descriptor desired by caller
* @size: requested resource region size
* @min: minimum size to allocate
* @max: maximum size to allocate
* @align: alignment requested, in bytes
* @alignf: alignment function, optional, called if not NULL
* @alignf_data: arbitrary data to pass to the @alignf function
*/
int allocate_resource(struct resource *root, struct resource *new,
resource_size_t size, resource_size_t min,
resource_size_t max, resource_size_t align,
void (*alignf)(void *, struct resource *,
resource_size_t, resource_size_t),
void *alignf_data)
{
int err;
write_lock(&resource_lock);
err = find_resource(root, new, size, min, max, align, alignf, alignf_data);
if (err >= 0 && __request_resource(root, new))
err = -EBUSY;
write_unlock(&resource_lock);
return err;
}
EXPORT_SYMBOL(allocate_resource);
/*
* Insert a resource into the resource tree. If successful, return NULL,
* otherwise return the conflicting resource (compare to __request_resource())
*/
static struct resource * __insert_resource(struct resource *parent, struct resource *new)
{
struct resource *first, *next;
for (;; parent = first) {
first = __request_resource(parent, new);
if (!first)
return first;
if (first == parent)
return first;
if ((first->start > new->start) || (first->end < new->end))
break;
if ((first->start == new->start) && (first->end == new->end))
break;
}
for (next = first; ; next = next->sibling) {
/* Partial overlap? Bad, and unfixable */
if (next->start < new->start || next->end > new->end)
return next;
if (!next->sibling)
break;
if (next->sibling->start > new->end)
break;
}
new->parent = parent;
new->sibling = next->sibling;
new->child = first;
next->sibling = NULL;
for (next = first; next; next = next->sibling)
next->parent = new;
if (parent->child == first) {
parent->child = new;
} else {
next = parent->child;
while (next->sibling != first)
next = next->sibling;
next->sibling = new;
}
return NULL;
}
/**
* insert_resource - Inserts a resource in the resource tree
* @parent: parent of the new resource
* @new: new resource to insert
*
* Returns 0 on success, -EBUSY if the resource can't be inserted.
*
* This function is equivalent to request_resource when no conflict
* happens. If a conflict happens, and the conflicting resources
* entirely fit within the range of the new resource, then the new
* resource is inserted and the conflicting resources become children of
* the new resource.
*/
int insert_resource(struct resource *parent, struct resource *new)
{
struct resource *conflict;
write_lock(&resource_lock);
conflict = __insert_resource(parent, new);
write_unlock(&resource_lock);
return conflict ? -EBUSY : 0;
}
/**
* insert_resource_expand_to_fit - Insert a resource into the resource tree
* @root: root resource descriptor
* @new: new resource to insert
*
* Insert a resource into the resource tree, possibly expanding it in order
* to make it encompass any conflicting resources.
*/
void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
{
if (new->parent)
return;
write_lock(&resource_lock);
for (;;) {
struct resource *conflict;
conflict = __insert_resource(root, new);
if (!conflict)
break;
if (conflict == root)
break;
/* Ok, expand resource to cover the conflict, then try again .. */
if (conflict->start < new->start)
new->start = conflict->start;
if (conflict->end > new->end)
new->end = conflict->end;
printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
}
write_unlock(&resource_lock);
}
/**
* adjust_resource - modify a resource's start and size
* @res: resource to modify
* @start: new start value
* @size: new size
*
* Given an existing resource, change its start and size to match the
* arguments. Returns 0 on success, -EBUSY if it can't fit.
* Existing children of the resource are assumed to be immutable.
*/
int adjust_resource(struct resource *res, resource_size_t start, resource_size_t size)
{
struct resource *tmp, *parent = res->parent;
resource_size_t end = start + size - 1;
int result = -EBUSY;
write_lock(&resource_lock);
if ((start < parent->start) || (end > parent->end))
goto out;
for (tmp = res->child; tmp; tmp = tmp->sibling) {
if ((tmp->start < start) || (tmp->end > end))
goto out;
}
if (res->sibling && (res->sibling->start <= end))
goto out;
tmp = parent->child;
if (tmp != res) {
while (tmp->sibling != res)
tmp = tmp->sibling;
if (start <= tmp->end)
goto out;
}
res->start = start;
res->end = end;
result = 0;
out:
write_unlock(&resource_lock);
return result;
}
static void __init __reserve_region_with_split(struct resource *root,
resource_size_t start, resource_size_t end,
const char *name)
{
struct resource *parent = root;
struct resource *conflict;
struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);
if (!res)
return;
res->name = name;
res->start = start;
res->end = end;
res->flags = IORESOURCE_BUSY;
for (;;) {
conflict = __request_resource(parent, res);
if (!conflict)
break;
if (conflict != parent) {
parent = conflict;
if (!(conflict->flags & IORESOURCE_BUSY))
continue;
}
/* Uhhuh, that didn't work out.. */
kfree(res);
res = NULL;
break;
}
if (!res) {
printk(KERN_DEBUG " __reserve_region_with_split: (%s) [%llx, %llx], res: (%s) [%llx, %llx]\n",
conflict->name, conflict->start, conflict->end,
name, start, end);
/* failed, split and try again */
/* conflict coverred whole area */
if (conflict->start <= start && conflict->end >= end)
return;
if (conflict->start > start)
__reserve_region_with_split(root, start, conflict->start-1, name);
if (!(conflict->flags & IORESOURCE_BUSY)) {
resource_size_t common_start, common_end;
common_start = max(conflict->start, start);
common_end = min(conflict->end, end);
if (common_start < common_end)
__reserve_region_with_split(root, common_start, common_end, name);
}
if (conflict->end < end)
__reserve_region_with_split(root, conflict->end+1, end, name);
}
}
void reserve_region_with_split(struct resource *root,
resource_size_t start, resource_size_t end,
const char *name)
{
write_lock(&resource_lock);
__reserve_region_with_split(root, start, end, name);
write_unlock(&resource_lock);
}
EXPORT_SYMBOL(adjust_resource);
/**
* resource_alignment - calculate resource's alignment
* @res: resource pointer
*
* Returns alignment on success, 0 (invalid alignment) on failure.
*/
resource_size_t resource_alignment(struct resource *res)
{
switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
case IORESOURCE_SIZEALIGN:
return resource_size(res);
case IORESOURCE_STARTALIGN:
return res->start;
default:
return 0;
}
}
/*
* This is compatibility stuff for IO resources.
*
* Note how this, unlike the above, knows about
* the IO flag meanings (busy etc).
*
* request_region creates a new busy region.
*
* check_region returns non-zero if the area is already busy.
*
* release_region releases a matching busy region.
*/
/**
* __request_region - create a new busy resource region
* @parent: parent resource descriptor
* @start: resource start address
* @n: resource region size
* @name: reserving caller's ID string
*/
struct resource * __request_region(struct resource *parent,
resource_size_t start, resource_size_t n,
const char *name)
{
struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);
if (res) {
res->name = name;
res->start = start;
res->end = start + n - 1;
res->flags = IORESOURCE_BUSY;
write_lock(&resource_lock);
for (;;) {
struct resource *conflict;
conflict = __request_resource(parent, res);
if (!conflict)
break;
if (conflict != parent) {
parent = conflict;
if (!(conflict->flags & IORESOURCE_BUSY))
continue;
}
/* Uhhuh, that didn't work out.. */
kfree(res);
res = NULL;
break;
}
write_unlock(&resource_lock);
}
return res;
}
EXPORT_SYMBOL(__request_region);
/**
* __check_region - check if a resource region is busy or free
* @parent: parent resource descriptor
* @start: resource start address
* @n: resource region size
*
* Returns 0 if the region is free at the moment it is checked,
* returns %-EBUSY if the region is busy.
*
* NOTE:
* This function is deprecated because its use is racy.
* Even if it returns 0, a subsequent call to request_region()
* may fail because another driver etc. just allocated the region.
* Do NOT use it. It will be removed from the kernel.
*/
int __check_region(struct resource *parent, resource_size_t start,
resource_size_t n)
{
struct resource * res;
res = __request_region(parent, start, n, "check-region");
if (!res)
return -EBUSY;
release_resource(res);
kfree(res);
return 0;
}
EXPORT_SYMBOL(__check_region);
/**
* __release_region - release a previously reserved resource region
* @parent: parent resource descriptor
* @start: resource start address
* @n: resource region size
*
* The described resource region must match a currently busy region.
*/
void __release_region(struct resource *parent, resource_size_t start,
resource_size_t n)
{
struct resource **p;
resource_size_t end;
p = &parent->child;
end = start + n - 1;
write_lock(&resource_lock);
for (;;) {
struct resource *res = *p;
if (!res)
break;
if (res->start <= start && res->end >= end) {
if (!(res->flags & IORESOURCE_BUSY)) {
p = &res->child;
continue;
}
if (res->start != start || res->end != end)
break;
*p = res->sibling;
write_unlock(&resource_lock);
kfree(res);
return;
}
p = &res->sibling;
}
write_unlock(&resource_lock);
printk(KERN_WARNING "Trying to free nonexistent resource "
"<%016llx-%016llx>\n", (unsigned long long)start,
(unsigned long long)end);
}
EXPORT_SYMBOL(__release_region);
/*
* Managed region resource
*/
struct region_devres {
struct resource *parent;
resource_size_t start;
resource_size_t n;
};
static void devm_region_release(struct device *dev, void *res)
{
struct region_devres *this = res;
__release_region(this->parent, this->start, this->n);
}
static int devm_region_match(struct device *dev, void *res, void *match_data)
{
struct region_devres *this = res, *match = match_data;
return this->parent == match->parent &&
this->start == match->start && this->n == match->n;
}
struct resource * __devm_request_region(struct device *dev,
struct resource *parent, resource_size_t start,
resource_size_t n, const char *name)
{
struct region_devres *dr = NULL;
struct resource *res;
dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
GFP_KERNEL);
if (!dr)
return NULL;
dr->parent = parent;
dr->start = start;
dr->n = n;
res = __request_region(parent, start, n, name);
if (res)
devres_add(dev, dr);
else
devres_free(dr);
return res;
}
EXPORT_SYMBOL(__devm_request_region);
void __devm_release_region(struct device *dev, struct resource *parent,
resource_size_t start, resource_size_t n)
{
struct region_devres match_data = { parent, start, n };
__release_region(parent, start, n);
WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
&match_data));
}
EXPORT_SYMBOL(__devm_release_region);
/*
* Called from init/main.c to reserve IO ports.
*/
#define MAXRESERVE 4
static int __init reserve_setup(char *str)
{
static int reserved;
static struct resource reserve[MAXRESERVE];
for (;;) {
int io_start, io_num;
int x = reserved;
if (get_option (&str, &io_start) != 2)
break;
if (get_option (&str, &io_num) == 0)
break;
if (x < MAXRESERVE) {
struct resource *res = reserve + x;
res->name = "reserved";
res->start = io_start;
res->end = io_start + io_num - 1;
res->flags = IORESOURCE_BUSY;
res->child = NULL;
if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
reserved = x+1;
}
}
return 1;
}
__setup("reserve=", reserve_setup);