Root/kernel/resource.c

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);
1158

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