[linux.git] / kernel / resource.c

/*
 *	linux/kernel/resource.c
 *
 * Copyright (C) 1999	Linus Torvalds
 * Copyright (C) 1999	Martin Mares <[email protected]>
 *
 * Arbitrary resource management.
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/sched.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 <asm/io.h>


struct resource ioport_resource = {
	.name	= "PCI IO",
	.start	= 0x0000,
	.end	= IO_SPACE_LIMIT,
	.flags	= IORESOURCE_IO,
};

EXPORT_SYMBOL(ioport_resource);

struct resource iomem_resource = {
	.name	= "PCI mem",
	.start	= 0UL,
	.end	= ~0UL,
	.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*lx-%0*lx : %s\n",
			depth * 2, "",
			width, r->start,
			width, r->end,
			r->name ? r->name : "<BAD>");
	return 0;
}

static 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 struct file_operations proc_ioports_operations = {
	.open		= ioports_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};

static 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)
{
	unsigned long start = new->start;
	unsigned long 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;
}

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);

struct resource *____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;
}

EXPORT_SYMBOL(____request_resource);

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);

/*
 * Find empty slot in the resource tree given range and alignment.
 */
static int find_resource(struct resource *root, struct resource *new,
			 unsigned long size,
			 unsigned long min, unsigned long max,
			 unsigned long align,
			 void (*alignf)(void *, struct resource *,
					unsigned long, unsigned long),
			 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 empty slot in the resource tree given range and alignment.
 */
int allocate_resource(struct resource *root, struct resource *new,
		      unsigned long size,
		      unsigned long min, unsigned long max,
		      unsigned long align,
		      void (*alignf)(void *, struct resource *,
				     unsigned long, unsigned long),
		      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_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 of 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 childs of
 * the new resource.  Otherwise the new resource becomes the child of
 * the conflicting resource
 */
int insert_resource(struct resource *parent, struct resource *new)
{
	int result;
	struct resource *first, *next;

	write_lock(&resource_lock);
 begin:
 	result = 0;
	first = __request_resource(parent, new);
	if (!first)
		goto out;

	result = -EBUSY;
	if (first == parent)
		goto out;

	/* Resource fully contained by the clashing resource? Recurse into it */
	if (first->start <= new->start && first->end >= new->end) {
		parent = first;
		goto begin;
	}

	for (next = first; ; next = next->sibling) {
		/* Partial overlap? Bad, and unfixable */
		if (next->start < new->start || next->end > new->end)
			goto out;
		if (!next->sibling)
			break;
		if (next->sibling->start > new->end)
			break;
	}

	result = 0;

	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;
	}

 out:
	write_unlock(&resource_lock);
	return result;
}

EXPORT_SYMBOL(insert_resource);

/*
 * Given an existing resource, change its start and size to match the
 * arguments.  Returns -EBUSY if it can't fit.  Existing children of
 * the resource are assumed to be immutable.
 */
int adjust_resource(struct resource *res, unsigned long start, unsigned long size)
{
	struct resource *tmp, *parent = res->parent;
	unsigned long 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;
}

EXPORT_SYMBOL(adjust_resource);

/*
 * 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.
 */
struct resource * __request_region(struct resource *parent, unsigned long start, unsigned long 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);

int __check_region(struct resource *parent, unsigned long start, unsigned long 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);

void __release_region(struct resource *parent, unsigned long start, unsigned long n)
{
	struct resource **p;
	unsigned long 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 <%08lx-%08lx>\n", start, end);
}

EXPORT_SYMBOL(__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);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/kernel/resource.c
	3	*
	4	* Copyright (C) 1999 Linus Torvalds
	5	* Copyright (C) 1999 Martin Mares <[email protected]>
	6	*
	7	* Arbitrary resource management.
	8	*/
	9
	10	#include <linux/config.h>
	11	#include <linux/module.h>
	12	#include <linux/sched.h>
	13	#include <linux/errno.h>
	14	#include <linux/ioport.h>
	15	#include <linux/init.h>
	16	#include <linux/slab.h>
	17	#include <linux/spinlock.h>
	18	#include <linux/fs.h>
	19	#include <linux/proc_fs.h>
	20	#include <linux/seq_file.h>
	21	#include <asm/io.h>
	22
	23
	24	struct resource ioport_resource = {
	25	.name = "PCI IO",
	26	.start = 0x0000,
	27	.end = IO_SPACE_LIMIT,
	28	.flags = IORESOURCE_IO,
	29	};
	30
	31	EXPORT_SYMBOL(ioport_resource);
	32
	33	struct resource iomem_resource = {
	34	.name = "PCI mem",
	35	.start = 0UL,
	36	.end = ~0UL,
	37	.flags = IORESOURCE_MEM,
	38	};
	39
	40	EXPORT_SYMBOL(iomem_resource);
	41
	42	static DEFINE_RWLOCK(resource_lock);
	43
	44	#ifdef CONFIG_PROC_FS
	45
	46	enum { MAX_IORES_LEVEL = 5 };
	47
	48	static void r_next(struct seq_file m, void v, loff_t pos)
	49	{
	50	struct resource *p = v;
	51	(*pos)++;
	52	if (p->child)
	53	return p->child;
	54	while (!p->sibling && p->parent)
	55	p = p->parent;
	56	return p->sibling;
	57	}
	58
	59	static void r_start(struct seq_file m, loff_t *pos)
	60	__acquires(resource_lock)
	61	{
	62	struct resource *p = m->private;
	63	loff_t l = 0;
	64	read_lock(&resource_lock);
65	for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
66	;
67	return p;
68	}
69
70	static void r_stop(struct seq_file m, void v)
71	__releases(resource_lock)
72	{
73	read_unlock(&resource_lock);
74	}
75
76	static int r_show(struct seq_file m, void v)
77	{
78	struct resource *root = m->private;
79	struct resource r = v, p;
80	int width = root->end < 0x10000 ? 4 : 8;
81	int depth;
82
83	for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
84	if (p->parent == root)
85	break;
86	seq_printf(m, "%s%0lx-%0*lx : %s\n",
87	depth * 2, "",
88	width, r->start,
89	width, r->end,
90	r->name ? r->name : "<BAD>");
91	return 0;
92	}
93
94	static struct seq_operations resource_op = {
95	.start = r_start,
96	.next = r_next,
97	.stop = r_stop,
98	.show = r_show,
99	};
100
101	static int ioports_open(struct inode inode, struct file file)
102	{
103	int res = seq_open(file, &resource_op);
104	if (!res) {
105	struct seq_file *m = file->private_data;
106	m->private = &ioport_resource;
107	}
108	return res;
109	}
110
111	static int iomem_open(struct inode inode, struct file file)
112	{
113	int res = seq_open(file, &resource_op);
114	if (!res) {
115	struct seq_file *m = file->private_data;
116	m->private = &iomem_resource;
117	}
118	return res;
119	}
120
121	static struct file_operations proc_ioports_operations = {
122	.open = ioports_open,
123	.read = seq_read,
124	.llseek = seq_lseek,
125	.release = seq_release,
126	};
127
128	static struct file_operations proc_iomem_operations = {
129	.open = iomem_open,
130	.read = seq_read,
131	.llseek = seq_lseek,
132	.release = seq_release,
133	};
134
135	static int __init ioresources_init(void)
136	{
137	struct proc_dir_entry *entry;
138
139	entry = create_proc_entry("ioports", 0, NULL);
140	if (entry)
141	entry->proc_fops = &proc_ioports_operations;
142	entry = create_proc_entry("iomem", 0, NULL);
143	if (entry)
144	entry->proc_fops = &proc_iomem_operations;
145	return 0;
146	}
147	__initcall(ioresources_init);
148
149	#endif /* CONFIG_PROC_FS */
150
151	/* Return the conflict entry if you can't request it */
152	static struct resource * __request_resource(struct resource root, struct resource new)
153	{
154	unsigned long start = new->start;
155	unsigned long end = new->end;
156	struct resource tmp, *p;
157
158	if (end < start)
159	return root;
160	if (start < root->start)
161	return root;
162	if (end > root->end)
163	return root;
164	p = &root->child;
165	for (;;) {
166	tmp = *p;
167	if (!tmp \|\| tmp->start > end) {
168	new->sibling = tmp;
169	*p = new;
170	new->parent = root;
171	return NULL;
172	}
173	p = &tmp->sibling;
174	if (tmp->end < start)
175	continue;
176	return tmp;
177	}
178	}
179
180	static int __release_resource(struct resource *old)
181	{
182	struct resource tmp, *p;
183
184	p = &old->parent->child;
185	for (;;) {
186	tmp = *p;
187	if (!tmp)
188	break;
189	if (tmp == old) {
190	*p = tmp->sibling;
191	old->parent = NULL;
192	return 0;
193	}
194	p = &tmp->sibling;
195	}
196	return -EINVAL;
197	}
198
199	int request_resource(struct resource root, struct resource new)
200	{
201	struct resource *conflict;
202
203	write_lock(&resource_lock);
204	conflict = __request_resource(root, new);
205	write_unlock(&resource_lock);
206	return conflict ? -EBUSY : 0;
207	}
208
209	EXPORT_SYMBOL(request_resource);
210
211	struct resource ____request_resource(struct resource root, struct resource *new)
212	{
213	struct resource *conflict;
214
215	write_lock(&resource_lock);
216	conflict = __request_resource(root, new);
217	write_unlock(&resource_lock);
218	return conflict;
219	}
220
221	EXPORT_SYMBOL(____request_resource);
222
223	int release_resource(struct resource *old)
224	{
225	int retval;
226
227	write_lock(&resource_lock);
228	retval = __release_resource(old);
229	write_unlock(&resource_lock);
230	return retval;
231	}
232
233	EXPORT_SYMBOL(release_resource);
234
235	/*
236	* Find empty slot in the resource tree given range and alignment.
237	*/
238	static int find_resource(struct resource root, struct resource new,
239	unsigned long size,
240	unsigned long min, unsigned long max,
241	unsigned long align,
242	void (alignf)(void , struct resource *,
243	unsigned long, unsigned long),
244	void *alignf_data)
245	{
246	struct resource *this = root->child;
247
248	new->start = root->start;
249	/*
250	* Skip past an allocated resource that starts at 0, since the assignment
251	* of this->start - 1 to new->end below would cause an underflow.
252	*/
253	if (this && this->start == 0) {
254	new->start = this->end + 1;
255	this = this->sibling;
256	}
257	for(;;) {
258	if (this)
259	new->end = this->start - 1;
260	else
261	new->end = root->end;
262	if (new->start < min)
263	new->start = min;
264	if (new->end > max)
265	new->end = max;
8c0e33c1	266	new->start = ALIGN(new->start, align);
1da177e4 LT	267	if (alignf)
1da177e4 LT	268	alignf(alignf_data, new, size, align);
b52402c7	269	if (new->start < new->end && new->end - new->start >= size - 1) {
1da177e4 LT	270	new->end = new->start + size - 1;
	271	return 0;
	272	}
	273	if (!this)
	274	break;
	275	new->start = this->end + 1;
	276	this = this->sibling;
	277	}
	278	return -EBUSY;
	279	}
	280
	281	/*
	282	* Allocate empty slot in the resource tree given range and alignment.
	283	*/
	284	int allocate_resource(struct resource root, struct resource new,
	285	unsigned long size,
	286	unsigned long min, unsigned long max,
	287	unsigned long align,
	288	void (alignf)(void , struct resource *,
	289	unsigned long, unsigned long),
	290	void *alignf_data)
	291	{
	292	int err;
	293
	294	write_lock(&resource_lock);
	295	err = find_resource(root, new, size, min, max, align, alignf, alignf_data);
	296	if (err >= 0 && __request_resource(root, new))
	297	err = -EBUSY;
	298	write_unlock(&resource_lock);
	299	return err;
	300	}
	301
	302	EXPORT_SYMBOL(allocate_resource);
	303
	304	/**
	305	* insert_resource - Inserts a resource in the resource tree
	306	* @parent: parent of the new resource
	307	* @new: new resource to insert
	308	*
	309	* Returns 0 on success, -EBUSY if the resource can't be inserted.
	310	*
	311	* This function is equivalent of request_resource when no conflict
	312	* happens. If a conflict happens, and the conflicting resources
	313	* entirely fit within the range of the new resource, then the new
	314	* resource is inserted and the conflicting resources become childs of
	315	* the new resource. Otherwise the new resource becomes the child of
	316	* the conflicting resource
	317	*/
	318	int insert_resource(struct resource parent, struct resource new)
	319	{
	320	int result;
	321	struct resource first, next;
	322
	323	write_lock(&resource_lock);
	324	begin:
	325	result = 0;
	326	first = __request_resource(parent, new);
	327	if (!first)
	328	goto out;
	329
	330	result = -EBUSY;
	331	if (first == parent)
	332	goto out;
	333
334	/* Resource fully contained by the clashing resource? Recurse into it */
335	if (first->start <= new->start && first->end >= new->end) {
336	parent = first;
337	goto begin;
338	}
339
340	for (next = first; ; next = next->sibling) {
341	/* Partial overlap? Bad, and unfixable */
342	if (next->start < new->start \|\| next->end > new->end)
343	goto out;
344	if (!next->sibling)
345	break;
346	if (next->sibling->start > new->end)
347	break;
348	}
349
350	result = 0;
351
352	new->parent = parent;
353	new->sibling = next->sibling;
354	new->child = first;
355
356	next->sibling = NULL;
357	for (next = first; next; next = next->sibling)
358	next->parent = new;
359
360	if (parent->child == first) {
361	parent->child = new;
362	} else {
363	next = parent->child;
364	while (next->sibling != first)
365	next = next->sibling;
366	next->sibling = new;
367	}
368
369	out:
370	write_unlock(&resource_lock);
371	return result;
372	}
373
374	EXPORT_SYMBOL(insert_resource);
375
376	/*
377	* Given an existing resource, change its start and size to match the
378	* arguments. Returns -EBUSY if it can't fit. Existing children of
379	* the resource are assumed to be immutable.
380	*/
381	int adjust_resource(struct resource *res, unsigned long start, unsigned long size)
382	{
383	struct resource tmp, parent = res->parent;
384	unsigned long end = start + size - 1;
385	int result = -EBUSY;
386
387	write_lock(&resource_lock);
388
389	if ((start < parent->start) \|\| (end > parent->end))
390	goto out;
391
392	for (tmp = res->child; tmp; tmp = tmp->sibling) {
393	if ((tmp->start < start) \|\| (tmp->end > end))
394	goto out;
395	}
396
397	if (res->sibling && (res->sibling->start <= end))
398	goto out;
399
400	tmp = parent->child;
401	if (tmp != res) {
402	while (tmp->sibling != res)
403	tmp = tmp->sibling;
404	if (start <= tmp->end)
405	goto out;
406	}
407
408	res->start = start;
409	res->end = end;
410	result = 0;
411
412	out:
413	write_unlock(&resource_lock);
414	return result;
415	}
416
417	EXPORT_SYMBOL(adjust_resource);
418
419	/*
420	* This is compatibility stuff for IO resources.
421	*
422	* Note how this, unlike the above, knows about
423	* the IO flag meanings (busy etc).
424	*
425	* Request-region creates a new busy region.
426	*
427	* Check-region returns non-zero if the area is already busy
428	*
429	* Release-region releases a matching busy region.
430	*/
431	struct resource * __request_region(struct resource parent, unsigned long start, unsigned long n, const char name)
432	{
dd392710	433	struct resource res = kzalloc(sizeof(res), GFP_KERNEL);
1da177e4 LT	434
1da177e4 LT	435	if (res) {
1da177e4 LT	436	res->name = name;
	437	res->start = start;
	438	res->end = start + n - 1;
	439	res->flags = IORESOURCE_BUSY;
	440
	441	write_lock(&resource_lock);
	442
	443	for (;;) {
	444	struct resource *conflict;
	445
	446	conflict = __request_resource(parent, res);
	447	if (!conflict)
	448	break;
	449	if (conflict != parent) {
	450	parent = conflict;
	451	if (!(conflict->flags & IORESOURCE_BUSY))
	452	continue;
	453	}
	454
	455	/* Uhhuh, that didn't work out.. */
	456	kfree(res);
	457	res = NULL;
	458	break;
	459	}
	460	write_unlock(&resource_lock);
	461	}
	462	return res;
	463	}
	464
	465	EXPORT_SYMBOL(__request_region);
	466
d974837a	467	int __check_region(struct resource *parent, unsigned long start, unsigned long n)
1da177e4 LT	468	{
	469	struct resource * res;
	470
	471	res = __request_region(parent, start, n, "check-region");
	472	if (!res)
	473	return -EBUSY;
	474
	475	release_resource(res);
	476	kfree(res);
	477	return 0;
	478	}
	479
	480	EXPORT_SYMBOL(__check_region);
	481
	482	void __release_region(struct resource *parent, unsigned long start, unsigned long n)
	483	{
	484	struct resource **p;
	485	unsigned long end;
	486
	487	p = &parent->child;
	488	end = start + n - 1;
	489
	490	write_lock(&resource_lock);
	491
	492	for (;;) {
	493	struct resource res = p;
	494
	495	if (!res)
	496	break;
	497	if (res->start <= start && res->end >= end) {
	498	if (!(res->flags & IORESOURCE_BUSY)) {
	499	p = &res->child;
	500	continue;
	501	}
	502	if (res->start != start \|\| res->end != end)
	503	break;
	504	*p = res->sibling;
	505	write_unlock(&resource_lock);
	506	kfree(res);
	507	return;
	508	}
	509	p = &res->sibling;
	510	}
	511
	512	write_unlock(&resource_lock);
	513
	514	printk(KERN_WARNING "Trying to free nonexistent resource <%08lx-%08lx>\n", start, end);
	515	}
	516
	517	EXPORT_SYMBOL(__release_region);
	518
	519	/*
	520	* Called from init/main.c to reserve IO ports.
	521	*/
	522	#define MAXRESERVE 4
	523	static int __init reserve_setup(char *str)
	524	{
	525	static int reserved;
	526	static struct resource reserve[MAXRESERVE];
	527
	528	for (;;) {
	529	int io_start, io_num;
	530	int x = reserved;
	531
532	if (get_option (&str, &io_start) != 2)
533	break;
534	if (get_option (&str, &io_num) == 0)
535	break;
536	if (x < MAXRESERVE) {
537	struct resource *res = reserve + x;
538	res->name = "reserved";
539	res->start = io_start;
540	res->end = io_start + io_num - 1;
541	res->flags = IORESOURCE_BUSY;
542	res->child = NULL;
543	if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
544	reserved = x+1;
545	}
546	}
547	return 1;
548	}
549
550	__setup("reserve=", reserve_setup);