resource.c

linux 2.6.19 kernel source code before patching

/*
 *	linux/kernel/resource.c
 *
 * Copyright (C) 1999	Linus Torvalds
 * Copyright (C) 1999	Martin Mares <[e-mail]>
 *
 * 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)
{
	struct proc_dir_entry *entry;

	entry = create_proc_entry("ioports", 0, NULL);
	if (entry)
		entry->proc_fops = &proc_ioports_operations;
	entry = create_proc_entry("iomem", 0, NULL);
	if (entry)
		entry->proc_fops = &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);

#ifdef CONFIG_MEMORY_HOTPLUG
/*
 * 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.
 */
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;
}
#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);