1/*
   2 *	linux/kernel/resource.c
   3 *
   4 * Copyright (C) 1999	Linus Torvalds
   5 * Copyright (C) 1999	Martin Mares <mj@ucw.cz>
   6 *
   7 * Arbitrary resource management.
   8 */
   9
  10#include <linux/export.h>
  11#include <linux/errno.h>
  12#include <linux/ioport.h>
  13#include <linux/init.h>
  14#include <linux/slab.h>
  15#include <linux/spinlock.h>
  16#include <linux/fs.h>
  17#include <linux/proc_fs.h>
  18#include <linux/sched.h>
  19#include <linux/seq_file.h>
  20#include <linux/device.h>
  21#include <linux/pfn.h>
  22#include <asm/io.h>
  23
  24
  25struct resource ioport_resource = {
  26	.name	= "PCI IO",
  27	.start	= 0,
  28	.end	= IO_SPACE_LIMIT,
  29	.flags	= IORESOURCE_IO,
  30};
  31EXPORT_SYMBOL(ioport_resource);
  32
  33struct resource iomem_resource = {
  34	.name	= "PCI mem",
  35	.start	= 0,
  36	.end	= -1,
  37	.flags	= IORESOURCE_MEM,
  38};
  39EXPORT_SYMBOL(iomem_resource);
  40
  41/* constraints to be met while allocating resources */
  42struct resource_constraint {
  43	resource_size_t min, max, align;
  44	resource_size_t (*alignf)(void *, const struct resource *,
  45			resource_size_t, resource_size_t);
  46	void *alignf_data;
  47};
  48
  49static DEFINE_RWLOCK(resource_lock);
  50
  51static void *r_next(struct seq_file *m, void *v, loff_t *pos)
  52{
  53	struct resource *p = v;
  54	(*pos)++;
  55	if (p->child)
  56		return p->child;
  57	while (!p->sibling && p->parent)
  58		p = p->parent;
  59	return p->sibling;
  60}
  61
  62#ifdef CONFIG_PROC_FS
  63
  64enum { MAX_IORES_LEVEL = 5 };
  65
  66static void *r_start(struct seq_file *m, loff_t *pos)
  67	__acquires(resource_lock)
  68{
  69	struct resource *p = m->private;
  70	loff_t l = 0;
  71	read_lock(&resource_lock);
  72	for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
  73		;
  74	return p;
  75}
  76
  77static void r_stop(struct seq_file *m, void *v)
  78	__releases(resource_lock)
  79{
  80	read_unlock(&resource_lock);
  81}
  82
  83static int r_show(struct seq_file *m, void *v)
  84{
  85	struct resource *root = m->private;
  86	struct resource *r = v, *p;
  87	int width = root->end < 0x10000 ? 4 : 8;
  88	int depth;
  89
  90	for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
  91		if (p->parent == root)
  92			break;
  93	seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
  94			depth * 2, "",
  95			width, (unsigned long long) r->start,
  96			width, (unsigned long long) r->end,
  97			r->name ? r->name : "<BAD>");
  98	return 0;
  99}
 100
 101static const struct seq_operations resource_op = {
 102	.start	= r_start,
 103	.next	= r_next,
 104	.stop	= r_stop,
 105	.show	= r_show,
 106};
 107
 108static int ioports_open(struct inode *inode, struct file *file)
 109{
 110	int res = seq_open(file, &resource_op);
 111	if (!res) {
 112		struct seq_file *m = file->private_data;
 113		m->private = &ioport_resource;
 114	}
 115	return res;
 116}
 117
 118static int iomem_open(struct inode *inode, struct file *file)
 119{
 120	int res = seq_open(file, &resource_op);
 121	if (!res) {
 122		struct seq_file *m = file->private_data;
 123		m->private = &iomem_resource;
 124	}
 125	return res;
 126}
 127
 128static const struct file_operations proc_ioports_operations = {
 129	.open		= ioports_open,
 130	.read		= seq_read,
 131	.llseek		= seq_lseek,
 132	.release	= seq_release,
 133};
 134
 135static const struct file_operations proc_iomem_operations = {
 136	.open		= iomem_open,
 137	.read		= seq_read,
 138	.llseek		= seq_lseek,
 139	.release	= seq_release,
 140};
 141
 142static int __init ioresources_init(void)
 143{
 144	proc_create("ioports", 0, NULL, &proc_ioports_operations);
 145	proc_create("iomem", 0, NULL, &proc_iomem_operations);
 146	return 0;
 147}
 148__initcall(ioresources_init);
 149
 150#endif /* CONFIG_PROC_FS */
 151
 152/* Return the conflict entry if you can't request it */
 153static struct resource * __request_resource(struct resource *root, struct resource *new)
 154{
 155	resource_size_t start = new->start;
 156	resource_size_t end = new->end;
 157	struct resource *tmp, **p;
 158
 159	if (end < start)
 160		return root;
 161	if (start < root->start)
 162		return root;
 163	if (end > root->end)
 164		return root;
 165	p = &root->child;
 166	for (;;) {
 167		tmp = *p;
 168		if (!tmp || tmp->start > end) {
 169			new->sibling = tmp;
 170			*p = new;
 171			new->parent = root;
 172			return NULL;
 173		}
 174		p = &tmp->sibling;
 175		if (tmp->end < start)
 176			continue;
 177		return tmp;
 178	}
 179}
 180
 181static int __release_resource(struct resource *old)
 182{
 183	struct resource *tmp, **p;
 184
 185	p = &old->parent->child;
 186	for (;;) {
 187		tmp = *p;
 188		if (!tmp)
 189			break;
 190		if (tmp == old) {
 191			*p = tmp->sibling;
 192			old->parent = NULL;
 193			return 0;
 194		}
 195		p = &tmp->sibling;
 196	}
 197	return -EINVAL;
 198}
 199
 200static void __release_child_resources(struct resource *r)
 201{
 202	struct resource *tmp, *p;
 203	resource_size_t size;
 204
 205	p = r->child;
 206	r->child = NULL;
 207	while (p) {
 208		tmp = p;
 209		p = p->sibling;
 210
 211		tmp->parent = NULL;
 212		tmp->sibling = NULL;
 213		__release_child_resources(tmp);
 214
 215		printk(KERN_DEBUG "release child resource %pR\n", tmp);
 216		/* need to restore size, and keep flags */
 217		size = resource_size(tmp);
 218		tmp->start = 0;
 219		tmp->end = size - 1;
 220	}
 221}
 222
 223void release_child_resources(struct resource *r)
 224{
 225	write_lock(&resource_lock);
 226	__release_child_resources(r);
 227	write_unlock(&resource_lock);
 228}
 229
 230/**
 231 * request_resource_conflict - request and reserve an I/O or memory resource
 232 * @root: root resource descriptor
 233 * @new: resource descriptor desired by caller
 234 *
 235 * Returns 0 for success, conflict resource on error.
 236 */
 237struct resource *request_resource_conflict(struct resource *root, struct resource *new)
 238{
 239	struct resource *conflict;
 240
 241	write_lock(&resource_lock);
 242	conflict = __request_resource(root, new);
 243	write_unlock(&resource_lock);
 244	return conflict;
 245}
 246
 247/**
 248 * request_resource - request and reserve an I/O or memory resource
 249 * @root: root resource descriptor
 250 * @new: resource descriptor desired by caller
 251 *
 252 * Returns 0 for success, negative error code on error.
 253 */
 254int request_resource(struct resource *root, struct resource *new)
 255{
 256	struct resource *conflict;
 257
 258	conflict = request_resource_conflict(root, new);
 259	return conflict ? -EBUSY : 0;
 260}
 261
 262EXPORT_SYMBOL(request_resource);
 263
 264/**
 265 * release_resource - release a previously reserved resource
 266 * @old: resource pointer
 267 */
 268int release_resource(struct resource *old)
 269{
 270	int retval;
 271
 272	write_lock(&resource_lock);
 273	retval = __release_resource(old);
 274	write_unlock(&resource_lock);
 275	return retval;
 276}
 277
 278EXPORT_SYMBOL(release_resource);
 279
 280#if !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
 281/*
 282 * Finds the lowest memory reosurce exists within [res->start.res->end)
 283 * the caller must specify res->start, res->end, res->flags and "name".
 284 * If found, returns 0, res is overwritten, if not found, returns -1.
 285 */
 286static int find_next_system_ram(struct resource *res, char *name)
 287{
 288	resource_size_t start, end;
 289	struct resource *p;
 290
 291	BUG_ON(!res);
 292
 293	start = res->start;
 294	end = res->end;
 295	BUG_ON(start >= end);
 296
 297	read_lock(&resource_lock);
 298	for (p = iomem_resource.child; p ; p = p->sibling) {
 299		/* system ram is just marked as IORESOURCE_MEM */
 300		if (p->flags != res->flags)
 301			continue;
 302		if (name && strcmp(p->name, name))
 303			continue;
 304		if (p->start > end) {
 305			p = NULL;
 306			break;
 307		}
 308		if ((p->end >= start) && (p->start < end))
 309			break;
 310	}
 311	read_unlock(&resource_lock);
 312	if (!p)
 313		return -1;
 314	/* copy data */
 315	if (res->start < p->start)
 316		res->start = p->start;
 317	if (res->end > p->end)
 318		res->end = p->end;
 319	return 0;
 320}
 321
 322/*
 323 * This function calls callback against all memory range of "System RAM"
 324 * which are marked as IORESOURCE_MEM and IORESOUCE_BUSY.
 325 * Now, this function is only for "System RAM".
 326 */
 327int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
 328		void *arg, int (*func)(unsigned long, unsigned long, void *))
 329{
 330	struct resource res;
 331	unsigned long pfn, end_pfn;
 332	u64 orig_end;
 333	int ret = -1;
 334
 335	res.start = (u64) start_pfn << PAGE_SHIFT;
 336	res.end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
 337	res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 338	orig_end = res.end;
 339	while ((res.start < res.end) &&
 340		(find_next_system_ram(&res, "System RAM") >= 0)) {
 341		pfn = (res.start + PAGE_SIZE - 1) >> PAGE_SHIFT;
 342		end_pfn = (res.end + 1) >> PAGE_SHIFT;
 343		if (end_pfn > pfn)
 344			ret = (*func)(pfn, end_pfn - pfn, arg);
 345		if (ret)
 346			break;
 347		res.start = res.end + 1;
 348		res.end = orig_end;
 349	}
 350	return ret;
 351}
 352
 353#endif
 354
 355static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg)
 356{
 357	return 1;
 358}
 359/*
 360 * This generic page_is_ram() returns true if specified address is
 361 * registered as "System RAM" in iomem_resource list.
 362 */
 363int __weak page_is_ram(unsigned long pfn)
 364{
 365	return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
 366}
 367
 368void __weak arch_remove_reservations(struct resource *avail)
 369{
 370}
 371
 372static resource_size_t simple_align_resource(void *data,
 373					     const struct resource *avail,
 374					     resource_size_t size,
 375					     resource_size_t align)
 376{
 377	return avail->start;
 378}
 379
 380static void resource_clip(struct resource *res, resource_size_t min,
 381			  resource_size_t max)
 382{
 383	if (res->start < min)
 384		res->start = min;
 385	if (res->end > max)
 386		res->end = max;
 387}
 388
 389static bool resource_contains(struct resource *res1, struct resource *res2)
 390{
 391	return res1->start <= res2->start && res1->end >= res2->end;
 392}
 393
 394/*
 395 * Find empty slot in the resource tree with the given range and
 396 * alignment constraints
 397 */
 398static int __find_resource(struct resource *root, struct resource *old,
 399			 struct resource *new,
 400			 resource_size_t  size,
 401			 struct resource_constraint *constraint)
 402{
 403	struct resource *this = root->child;
 404	struct resource tmp = *new, avail, alloc;
 405
 406	tmp.flags = new->flags;
 407	tmp.start = root->start;
 408	/*
 409	 * Skip past an allocated resource that starts at 0, since the assignment
 410	 * of this->start - 1 to tmp->end below would cause an underflow.
 411	 */
 412	if (this && this->start == root->start) {
 413		tmp.start = (this == old) ? old->start : this->end + 1;
 414		this = this->sibling;
 415	}
 416	for(;;) {
 417		if (this)
 418			tmp.end = (this == old) ?  this->end : this->start - 1;
 419		else
 420			tmp.end = root->end;
 421
 422		if (tmp.end < tmp.start)
 423			goto next;
 424
 425		resource_clip(&tmp, constraint->min, constraint->max);
 426		arch_remove_reservations(&tmp);
 427
 428		/* Check for overflow after ALIGN() */
 429		avail = *new;
 430		avail.start = ALIGN(tmp.start, constraint->align);
 431		avail.end = tmp.end;
 432		if (avail.start >= tmp.start) {
 433			alloc.start = constraint->alignf(constraint->alignf_data, &avail,
 434					size, constraint->align);
 435			alloc.end = alloc.start + size - 1;
 436			if (resource_contains(&avail, &alloc)) {
 437				new->start = alloc.start;
 438				new->end = alloc.end;
 439				return 0;
 440			}
 441		}
 442
 443next:		if (!this || this->end == root->end)
 444			break;
 445
 446		if (this != old)
 447			tmp.start = this->end + 1;
 448		this = this->sibling;
 449	}
 450	return -EBUSY;
 451}
 452
 453/*
 454 * Find empty slot in the resource tree given range and alignment.
 455 */
 456static int find_resource(struct resource *root, struct resource *new,
 457			resource_size_t size,
 458			struct resource_constraint  *constraint)
 459{
 460	return  __find_resource(root, NULL, new, size, constraint);
 461}
 462
 463/**
 464 * reallocate_resource - allocate a slot in the resource tree given range & alignment.
 465 *	The resource will be relocated if the new size cannot be reallocated in the
 466 *	current location.
 467 *
 468 * @root: root resource descriptor
 469 * @old:  resource descriptor desired by caller
 470 * @newsize: new size of the resource descriptor
 471 * @constraint: the size and alignment constraints to be met.
 472 */
 473int reallocate_resource(struct resource *root, struct resource *old,
 474			resource_size_t newsize,
 475			struct resource_constraint  *constraint)
 476{
 477	int err=0;
 478	struct resource new = *old;
 479	struct resource *conflict;
 480
 481	write_lock(&resource_lock);
 482
 483	if ((err = __find_resource(root, old, &new, newsize, constraint)))
 484		goto out;
 485
 486	if (resource_contains(&new, old)) {
 487		old->start = new.start;
 488		old->end = new.end;
 489		goto out;
 490	}
 491
 492	if (old->child) {
 493		err = -EBUSY;
 494		goto out;
 495	}
 496
 497	if (resource_contains(old, &new)) {
 498		old->start = new.start;
 499		old->end = new.end;
 500	} else {
 501		__release_resource(old);
 502		*old = new;
 503		conflict = __request_resource(root, old);
 504		BUG_ON(conflict);
 505	}
 506out:
 507	write_unlock(&resource_lock);
 508	return err;
 509}
 510
 511
 512/**
 513 * allocate_resource - allocate empty slot in the resource tree given range & alignment.
 514 * 	The resource will be reallocated with a new size if it was already allocated
 515 * @root: root resource descriptor
 516 * @new: resource descriptor desired by caller
 517 * @size: requested resource region size
 518 * @min: minimum boundary to allocate
 519 * @max: maximum boundary to allocate
 520 * @align: alignment requested, in bytes
 521 * @alignf: alignment function, optional, called if not NULL
 522 * @alignf_data: arbitrary data to pass to the @alignf function
 523 */
 524int allocate_resource(struct resource *root, struct resource *new,
 525		      resource_size_t size, resource_size_t min,
 526		      resource_size_t max, resource_size_t align,
 527		      resource_size_t (*alignf)(void *,
 528						const struct resource *,
 529						resource_size_t,
 530						resource_size_t),
 531		      void *alignf_data)
 532{
 533	int err;
 534	struct resource_constraint constraint;
 535
 536	if (!alignf)
 537		alignf = simple_align_resource;
 538
 539	constraint.min = min;
 540	constraint.max = max;
 541	constraint.align = align;
 542	constraint.alignf = alignf;
 543	constraint.alignf_data = alignf_data;
 544
 545	if ( new->parent ) {
 546		/* resource is already allocated, try reallocating with
 547		   the new constraints */
 548		return reallocate_resource(root, new, size, &constraint);
 549	}
 550
 551	write_lock(&resource_lock);
 552	err = find_resource(root, new, size, &constraint);
 553	if (err >= 0 && __request_resource(root, new))
 554		err = -EBUSY;
 555	write_unlock(&resource_lock);
 556	return err;
 557}
 558
 559EXPORT_SYMBOL(allocate_resource);
 560
 561/**
 562 * lookup_resource - find an existing resource by a resource start address
 563 * @root: root resource descriptor
 564 * @start: resource start address
 565 *
 566 * Returns a pointer to the resource if found, NULL otherwise
 567 */
 568struct resource *lookup_resource(struct resource *root, resource_size_t start)
 569{
 570	struct resource *res;
 571
 572	read_lock(&resource_lock);
 573	for (res = root->child; res; res = res->sibling) {
 574		if (res->start == start)
 575			break;
 576	}
 577	read_unlock(&resource_lock);
 578
 579	return res;
 580}
 581
 582/*
 583 * Insert a resource into the resource tree. If successful, return NULL,
 584 * otherwise return the conflicting resource (compare to __request_resource())
 585 */
 586static struct resource * __insert_resource(struct resource *parent, struct resource *new)
 587{
 588	struct resource *first, *next;
 589
 590	for (;; parent = first) {
 591		first = __request_resource(parent, new);
 592		if (!first)
 593			return first;
 594
 595		if (first == parent)
 596			return first;
 597		if (WARN_ON(first == new))	/* duplicated insertion */
 598			return first;
 599
 600		if ((first->start > new->start) || (first->end < new->end))
 601			break;
 602		if ((first->start == new->start) && (first->end == new->end))
 603			break;
 604	}
 605
 606	for (next = first; ; next = next->sibling) {
 607		/* Partial overlap? Bad, and unfixable */
 608		if (next->start < new->start || next->end > new->end)
 609			return next;
 610		if (!next->sibling)
 611			break;
 612		if (next->sibling->start > new->end)
 613			break;
 614	}
 615
 616	new->parent = parent;
 617	new->sibling = next->sibling;
 618	new->child = first;
 619
 620	next->sibling = NULL;
 621	for (next = first; next; next = next->sibling)
 622		next->parent = new;
 623
 624	if (parent->child == first) {
 625		parent->child = new;
 626	} else {
 627		next = parent->child;
 628		while (next->sibling != first)
 629			next = next->sibling;
 630		next->sibling = new;
 631	}
 632	return NULL;
 633}
 634
 635/**
 636 * insert_resource_conflict - Inserts resource in the resource tree
 637 * @parent: parent of the new resource
 638 * @new: new resource to insert
 639 *
 640 * Returns 0 on success, conflict resource if the resource can't be inserted.
 641 *
 642 * This function is equivalent to request_resource_conflict when no conflict
 643 * happens. If a conflict happens, and the conflicting resources
 644 * entirely fit within the range of the new resource, then the new
 645 * resource is inserted and the conflicting resources become children of
 646 * the new resource.
 647 */
 648struct resource *insert_resource_conflict(struct resource *parent, struct resource *new)
 649{
 650	struct resource *conflict;
 651
 652	write_lock(&resource_lock);
 653	conflict = __insert_resource(parent, new);
 654	write_unlock(&resource_lock);
 655	return conflict;
 656}
 657
 658/**
 659 * insert_resource - Inserts a resource in the resource tree
 660 * @parent: parent of the new resource
 661 * @new: new resource to insert
 662 *
 663 * Returns 0 on success, -EBUSY if the resource can't be inserted.
 664 */
 665int insert_resource(struct resource *parent, struct resource *new)
 666{
 667	struct resource *conflict;
 668
 669	conflict = insert_resource_conflict(parent, new);
 670	return conflict ? -EBUSY : 0;
 671}
 672
 673/**
 674 * insert_resource_expand_to_fit - Insert a resource into the resource tree
 675 * @root: root resource descriptor
 676 * @new: new resource to insert
 677 *
 678 * Insert a resource into the resource tree, possibly expanding it in order
 679 * to make it encompass any conflicting resources.
 680 */
 681void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
 682{
 683	if (new->parent)
 684		return;
 685
 686	write_lock(&resource_lock);
 687	for (;;) {
 688		struct resource *conflict;
 689
 690		conflict = __insert_resource(root, new);
 691		if (!conflict)
 692			break;
 693		if (conflict == root)
 694			break;
 695
 696		/* Ok, expand resource to cover the conflict, then try again .. */
 697		if (conflict->start < new->start)
 698			new->start = conflict->start;
 699		if (conflict->end > new->end)
 700			new->end = conflict->end;
 701
 702		printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
 703	}
 704	write_unlock(&resource_lock);
 705}
 706
 707/**
 708 * adjust_resource - modify a resource's start and size
 709 * @res: resource to modify
 710 * @start: new start value
 711 * @size: new size
 712 *
 713 * Given an existing resource, change its start and size to match the
 714 * arguments.  Returns 0 on success, -EBUSY if it can't fit.
 715 * Existing children of the resource are assumed to be immutable.
 716 */
 717int adjust_resource(struct resource *res, resource_size_t start, resource_size_t size)
 718{
 719	struct resource *tmp, *parent = res->parent;
 720	resource_size_t end = start + size - 1;
 721	int result = -EBUSY;
 722
 723	write_lock(&resource_lock);
 724
 725	if ((start < parent->start) || (end > parent->end))
 726		goto out;
 727
 728	for (tmp = res->child; tmp; tmp = tmp->sibling) {
 729		if ((tmp->start < start) || (tmp->end > end))
 730			goto out;
 731	}
 732
 733	if (res->sibling && (res->sibling->start <= end))
 734		goto out;
 735
 736	tmp = parent->child;
 737	if (tmp != res) {
 738		while (tmp->sibling != res)
 739			tmp = tmp->sibling;
 740		if (start <= tmp->end)
 741			goto out;
 742	}
 743
 744	res->start = start;
 745	res->end = end;
 746	result = 0;
 747
 748 out:
 749	write_unlock(&resource_lock);
 750	return result;
 751}
 752EXPORT_SYMBOL(adjust_resource);
 753
 754static void __init __reserve_region_with_split(struct resource *root,
 755		resource_size_t start, resource_size_t end,
 756		const char *name)
 757{
 758	struct resource *parent = root;
 759	struct resource *conflict;
 760	struct resource *res = kzalloc(sizeof(*res), GFP_ATOMIC);
 761
 762	if (!res)
 763		return;
 764
 765	res->name = name;
 766	res->start = start;
 767	res->end = end;
 768	res->flags = IORESOURCE_BUSY;
 769
 770	conflict = __request_resource(parent, res);
 771	if (!conflict)
 772		return;
 773
 774	/* failed, split and try again */
 775	kfree(res);
 776
 777	/* conflict covered whole area */
 778	if (conflict->start <= start && conflict->end >= end)
 779		return;
 780
 781	if (conflict->start > start)
 782		__reserve_region_with_split(root, start, conflict->start-1, name);
 783	if (conflict->end < end)
 784		__reserve_region_with_split(root, conflict->end+1, end, name);
 785}
 786
 787void __init reserve_region_with_split(struct resource *root,
 788		resource_size_t start, resource_size_t end,
 789		const char *name)
 790{
 791	write_lock(&resource_lock);
 792	__reserve_region_with_split(root, start, end, name);
 793	write_unlock(&resource_lock);
 794}
 
 
 795
 796/**
 797 * resource_alignment - calculate resource's alignment
 798 * @res: resource pointer
 799 *
 800 * Returns alignment on success, 0 (invalid alignment) on failure.
 801 */
 802resource_size_t resource_alignment(struct resource *res)
 803{
 804	switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
 805	case IORESOURCE_SIZEALIGN:
 806		return resource_size(res);
 807	case IORESOURCE_STARTALIGN:
 808		return res->start;
 809	default:
 810		return 0;
 811	}
 812}
 813
 814/*
 815 * This is compatibility stuff for IO resources.
 816 *
 817 * Note how this, unlike the above, knows about
 818 * the IO flag meanings (busy etc).
 819 *
 820 * request_region creates a new busy region.
 821 *
 822 * check_region returns non-zero if the area is already busy.
 823 *
 824 * release_region releases a matching busy region.
 825 */
 826
 827static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait);
 828
 829/**
 830 * __request_region - create a new busy resource region
 831 * @parent: parent resource descriptor
 832 * @start: resource start address
 833 * @n: resource region size
 834 * @name: reserving caller's ID string
 835 * @flags: IO resource flags
 836 */
 837struct resource * __request_region(struct resource *parent,
 838				   resource_size_t start, resource_size_t n,
 839				   const char *name, int flags)
 840{
 841	DECLARE_WAITQUEUE(wait, current);
 842	struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);
 843
 844	if (!res)
 845		return NULL;
 846
 847	res->name = name;
 848	res->start = start;
 849	res->end = start + n - 1;
 850	res->flags = IORESOURCE_BUSY;
 851	res->flags |= flags;
 852
 853	write_lock(&resource_lock);
 854
 855	for (;;) {
 856		struct resource *conflict;
 857
 858		conflict = __request_resource(parent, res);
 859		if (!conflict)
 860			break;
 861		if (conflict != parent) {
 862			parent = conflict;
 863			if (!(conflict->flags & IORESOURCE_BUSY))
 864				continue;
 865		}
 866		if (conflict->flags & flags & IORESOURCE_MUXED) {
 867			add_wait_queue(&muxed_resource_wait, &wait);
 868			write_unlock(&resource_lock);
 869			set_current_state(TASK_UNINTERRUPTIBLE);
 870			schedule();
 871			remove_wait_queue(&muxed_resource_wait, &wait);
 872			write_lock(&resource_lock);
 873			continue;
 874		}
 875		/* Uhhuh, that didn't work out.. */
 876		kfree(res);
 877		res = NULL;
 878		break;
 879	}
 880	write_unlock(&resource_lock);
 881	return res;
 882}
 883EXPORT_SYMBOL(__request_region);
 884
 885/**
 886 * __check_region - check if a resource region is busy or free
 887 * @parent: parent resource descriptor
 888 * @start: resource start address
 889 * @n: resource region size
 890 *
 891 * Returns 0 if the region is free at the moment it is checked,
 892 * returns %-EBUSY if the region is busy.
 893 *
 894 * NOTE:
 895 * This function is deprecated because its use is racy.
 896 * Even if it returns 0, a subsequent call to request_region()
 897 * may fail because another driver etc. just allocated the region.
 898 * Do NOT use it.  It will be removed from the kernel.
 899 */
 900int __check_region(struct resource *parent, resource_size_t start,
 901			resource_size_t n)
 902{
 903	struct resource * res;
 904
 905	res = __request_region(parent, start, n, "check-region", 0);
 906	if (!res)
 907		return -EBUSY;
 908
 909	release_resource(res);
 910	kfree(res);
 911	return 0;
 912}
 913EXPORT_SYMBOL(__check_region);
 914
 915/**
 916 * __release_region - release a previously reserved resource region
 917 * @parent: parent resource descriptor
 918 * @start: resource start address
 919 * @n: resource region size
 920 *
 921 * The described resource region must match a currently busy region.
 922 */
 923void __release_region(struct resource *parent, resource_size_t start,
 924			resource_size_t n)
 925{
 926	struct resource **p;
 927	resource_size_t end;
 928
 929	p = &parent->child;
 930	end = start + n - 1;
 931
 932	write_lock(&resource_lock);
 933
 934	for (;;) {
 935		struct resource *res = *p;
 936
 937		if (!res)
 938			break;
 939		if (res->start <= start && res->end >= end) {
 940			if (!(res->flags & IORESOURCE_BUSY)) {
 941				p = &res->child;
 942				continue;
 943			}
 944			if (res->start != start || res->end != end)
 945				break;
 946			*p = res->sibling;
 947			write_unlock(&resource_lock);
 948			if (res->flags & IORESOURCE_MUXED)
 949				wake_up(&muxed_resource_wait);
 950			kfree(res);
 951			return;
 952		}
 953		p = &res->sibling;
 954	}
 955
 956	write_unlock(&resource_lock);
 957
 958	printk(KERN_WARNING "Trying to free nonexistent resource "
 959		"<%016llx-%016llx>\n", (unsigned long long)start,
 960		(unsigned long long)end);
 961}
 962EXPORT_SYMBOL(__release_region);
 963
 964/*
 965 * Managed region resource
 966 */
 967struct region_devres {
 968	struct resource *parent;
 969	resource_size_t start;
 970	resource_size_t n;
 971};
 972
 973static void devm_region_release(struct device *dev, void *res)
 974{
 975	struct region_devres *this = res;
 976
 977	__release_region(this->parent, this->start, this->n);
 978}
 979
 980static int devm_region_match(struct device *dev, void *res, void *match_data)
 981{
 982	struct region_devres *this = res, *match = match_data;
 983
 984	return this->parent == match->parent &&
 985		this->start == match->start && this->n == match->n;
 986}
 987
 988struct resource * __devm_request_region(struct device *dev,
 989				struct resource *parent, resource_size_t start,
 990				resource_size_t n, const char *name)
 991{
 992	struct region_devres *dr = NULL;
 993	struct resource *res;
 994
 995	dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
 996			  GFP_KERNEL);
 997	if (!dr)
 998		return NULL;
 999
1000	dr->parent = parent;
1001	dr->start = start;
1002	dr->n = n;
1003
1004	res = __request_region(parent, start, n, name, 0);
1005	if (res)
1006		devres_add(dev, dr);
1007	else
1008		devres_free(dr);
1009
1010	return res;
1011}
1012EXPORT_SYMBOL(__devm_request_region);
1013
1014void __devm_release_region(struct device *dev, struct resource *parent,
1015			   resource_size_t start, resource_size_t n)
1016{
1017	struct region_devres match_data = { parent, start, n };
1018
1019	__release_region(parent, start, n);
1020	WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
1021			       &match_data));
1022}
1023EXPORT_SYMBOL(__devm_release_region);
1024
1025/*
1026 * Called from init/main.c to reserve IO ports.
1027 */
1028#define MAXRESERVE 4
1029static int __init reserve_setup(char *str)
1030{
1031	static int reserved;
1032	static struct resource reserve[MAXRESERVE];
1033
1034	for (;;) {
1035		unsigned int io_start, io_num;
1036		int x = reserved;
1037
1038		if (get_option (&str, &io_start) != 2)
1039			break;
1040		if (get_option (&str, &io_num)   == 0)
1041			break;
1042		if (x < MAXRESERVE) {
1043			struct resource *res = reserve + x;
1044			res->name = "reserved";
1045			res->start = io_start;
1046			res->end = io_start + io_num - 1;
1047			res->flags = IORESOURCE_BUSY;
1048			res->child = NULL;
1049			if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
1050				reserved = x+1;
1051		}
1052	}
1053	return 1;
1054}
1055
1056__setup("reserve=", reserve_setup);
1057
1058/*
1059 * Check if the requested addr and size spans more than any slot in the
1060 * iomem resource tree.
1061 */
1062int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
1063{
1064	struct resource *p = &iomem_resource;
1065	int err = 0;
1066	loff_t l;
1067
1068	read_lock(&resource_lock);
1069	for (p = p->child; p ; p = r_next(NULL, p, &l)) {
1070		/*
1071		 * We can probably skip the resources without
1072		 * IORESOURCE_IO attribute?
1073		 */
1074		if (p->start >= addr + size)
1075			continue;
1076		if (p->end < addr)
1077			continue;
1078		if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
1079		    PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1))
1080			continue;
1081		/*
1082		 * if a resource is "BUSY", it's not a hardware resource
1083		 * but a driver mapping of such a resource; we don't want
1084		 * to warn for those; some drivers legitimately map only
1085		 * partial hardware resources. (example: vesafb)
1086		 */
1087		if (p->flags & IORESOURCE_BUSY)
1088			continue;
1089
1090		printk(KERN_WARNING "resource map sanity check conflict: "
1091		       "0x%llx 0x%llx 0x%llx 0x%llx %s\n",
1092		       (unsigned long long)addr,
1093		       (unsigned long long)(addr + size - 1),
1094		       (unsigned long long)p->start,
1095		       (unsigned long long)p->end,
1096		       p->name);
1097		err = -1;
1098		break;
1099	}
1100	read_unlock(&resource_lock);
1101
1102	return err;
1103}
1104
1105#ifdef CONFIG_STRICT_DEVMEM
1106static int strict_iomem_checks = 1;
1107#else
1108static int strict_iomem_checks;
1109#endif
1110
1111/*
1112 * check if an address is reserved in the iomem resource tree
1113 * returns 1 if reserved, 0 if not reserved.
1114 */
1115int iomem_is_exclusive(u64 addr)
1116{
1117	struct resource *p = &iomem_resource;
1118	int err = 0;
1119	loff_t l;
1120	int size = PAGE_SIZE;
1121
1122	if (!strict_iomem_checks)
1123		return 0;
1124
1125	addr = addr & PAGE_MASK;
1126
1127	read_lock(&resource_lock);
1128	for (p = p->child; p ; p = r_next(NULL, p, &l)) {
1129		/*
1130		 * We can probably skip the resources without
1131		 * IORESOURCE_IO attribute?
1132		 */
1133		if (p->start >= addr + size)
1134			break;
1135		if (p->end < addr)
1136			continue;
1137		if (p->flags & IORESOURCE_BUSY &&
1138		     p->flags & IORESOURCE_EXCLUSIVE) {
1139			err = 1;
1140			break;
1141		}
1142	}
1143	read_unlock(&resource_lock);
1144
1145	return err;
1146}
1147
1148static int __init strict_iomem(char *str)
1149{
1150	if (strstr(str, "relaxed"))
1151		strict_iomem_checks = 0;
1152	if (strstr(str, "strict"))
1153		strict_iomem_checks = 1;
1154	return 1;
1155}
1156
1157__setup("iomem=", strict_iomem);