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/module.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        resource_clip(&tmp, constraint->min, constraint->max);
423        arch_remove_reservations(&tmp);
424
425        /* Check for overflow after ALIGN() */
426        avail = *new;
427        avail.start = ALIGN(tmp.start, constraint->align);
428        avail.end = tmp.end;
429        if (avail.start >= tmp.start) {
430            alloc.start = constraint->alignf(constraint->alignf_data, &avail,
431                    size, constraint->align);
432            alloc.end = alloc.start + size - 1;
433            if (resource_contains(&avail, &alloc)) {
434                new->start = alloc.start;
435                new->end = alloc.end;
436                return 0;
437            }
438        }
439        if (!this)
440            break;
441        if (this != old)
442            tmp.start = this->end + 1;
443        this = this->sibling;
444    }
445    return -EBUSY;
446}
447
448/*
449 * Find empty slot in the resource tree given range and alignment.
450 */
451static int find_resource(struct resource *root, struct resource *new,
452            resource_size_t size,
453            struct resource_constraint *constraint)
454{
455    return __find_resource(root, NULL, new, size, constraint);
456}
457
458/**
459 * reallocate_resource - allocate a slot in the resource tree given range & alignment.
460 * The resource will be relocated if the new size cannot be reallocated in the
461 * current location.
462 *
463 * @root: root resource descriptor
464 * @old: resource descriptor desired by caller
465 * @newsize: new size of the resource descriptor
466 * @constraint: the size and alignment constraints to be met.
467 */
468int reallocate_resource(struct resource *root, struct resource *old,
469            resource_size_t newsize,
470            struct resource_constraint *constraint)
471{
472    int err=0;
473    struct resource new = *old;
474    struct resource *conflict;
475
476    write_lock(&resource_lock);
477
478    if ((err = __find_resource(root, old, &new, newsize, constraint)))
479        goto out;
480
481    if (resource_contains(&new, old)) {
482        old->start = new.start;
483        old->end = new.end;
484        goto out;
485    }
486
487    if (old->child) {
488        err = -EBUSY;
489        goto out;
490    }
491
492    if (resource_contains(old, &new)) {
493        old->start = new.start;
494        old->end = new.end;
495    } else {
496        __release_resource(old);
497        *old = new;
498        conflict = __request_resource(root, old);
499        BUG_ON(conflict);
500    }
501out:
502    write_unlock(&resource_lock);
503    return err;
504}
505
506
507/**
508 * allocate_resource - allocate empty slot in the resource tree given range & alignment.
509 * The resource will be reallocated with a new size if it was already allocated
510 * @root: root resource descriptor
511 * @new: resource descriptor desired by caller
512 * @size: requested resource region size
513 * @min: minimum size to allocate
514 * @max: maximum size to allocate
515 * @align: alignment requested, in bytes
516 * @alignf: alignment function, optional, called if not NULL
517 * @alignf_data: arbitrary data to pass to the @alignf function
518 */
519int allocate_resource(struct resource *root, struct resource *new,
520              resource_size_t size, resource_size_t min,
521              resource_size_t max, resource_size_t align,
522              resource_size_t (*alignf)(void *,
523                        const struct resource *,
524                        resource_size_t,
525                        resource_size_t),
526              void *alignf_data)
527{
528    int err;
529    struct resource_constraint constraint;
530
531    if (!alignf)
532        alignf = simple_align_resource;
533
534    constraint.min = min;
535    constraint.max = max;
536    constraint.align = align;
537    constraint.alignf = alignf;
538    constraint.alignf_data = alignf_data;
539
540    if ( new->parent ) {
541        /* resource is already allocated, try reallocating with
542           the new constraints */
543        return reallocate_resource(root, new, size, &constraint);
544    }
545
546    write_lock(&resource_lock);
547    err = find_resource(root, new, size, &constraint);
548    if (err >= 0 && __request_resource(root, new))
549        err = -EBUSY;
550    write_unlock(&resource_lock);
551    return err;
552}
553
554EXPORT_SYMBOL(allocate_resource);
555
556/*
557 * Insert a resource into the resource tree. If successful, return NULL,
558 * otherwise return the conflicting resource (compare to __request_resource())
559 */
560static struct resource * __insert_resource(struct resource *parent, struct resource *new)
561{
562    struct resource *first, *next;
563
564    for (;; parent = first) {
565        first = __request_resource(parent, new);
566        if (!first)
567            return first;
568
569        if (first == parent)
570            return first;
571        if (WARN_ON(first == new)) /* duplicated insertion */
572            return first;
573
574        if ((first->start > new->start) || (first->end < new->end))
575            break;
576        if ((first->start == new->start) && (first->end == new->end))
577            break;
578    }
579
580    for (next = first; ; next = next->sibling) {
581        /* Partial overlap? Bad, and unfixable */
582        if (next->start < new->start || next->end > new->end)
583            return next;
584        if (!next->sibling)
585            break;
586        if (next->sibling->start > new->end)
587            break;
588    }
589
590    new->parent = parent;
591    new->sibling = next->sibling;
592    new->child = first;
593
594    next->sibling = NULL;
595    for (next = first; next; next = next->sibling)
596        next->parent = new;
597
598    if (parent->child == first) {
599        parent->child = new;
600    } else {
601        next = parent->child;
602        while (next->sibling != first)
603            next = next->sibling;
604        next->sibling = new;
605    }
606    return NULL;
607}
608
609/**
610 * insert_resource_conflict - Inserts resource in the resource tree
611 * @parent: parent of the new resource
612 * @new: new resource to insert
613 *
614 * Returns 0 on success, conflict resource if the resource can't be inserted.
615 *
616 * This function is equivalent to request_resource_conflict when no conflict
617 * happens. If a conflict happens, and the conflicting resources
618 * entirely fit within the range of the new resource, then the new
619 * resource is inserted and the conflicting resources become children of
620 * the new resource.
621 */
622struct resource *insert_resource_conflict(struct resource *parent, struct resource *new)
623{
624    struct resource *conflict;
625
626    write_lock(&resource_lock);
627    conflict = __insert_resource(parent, new);
628    write_unlock(&resource_lock);
629    return conflict;
630}
631
632/**
633 * insert_resource - Inserts a resource in the resource tree
634 * @parent: parent of the new resource
635 * @new: new resource to insert
636 *
637 * Returns 0 on success, -EBUSY if the resource can't be inserted.
638 */
639int insert_resource(struct resource *parent, struct resource *new)
640{
641    struct resource *conflict;
642
643    conflict = insert_resource_conflict(parent, new);
644    return conflict ? -EBUSY : 0;
645}
646
647/**
648 * insert_resource_expand_to_fit - Insert a resource into the resource tree
649 * @root: root resource descriptor
650 * @new: new resource to insert
651 *
652 * Insert a resource into the resource tree, possibly expanding it in order
653 * to make it encompass any conflicting resources.
654 */
655void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
656{
657    if (new->parent)
658        return;
659
660    write_lock(&resource_lock);
661    for (;;) {
662        struct resource *conflict;
663
664        conflict = __insert_resource(root, new);
665        if (!conflict)
666            break;
667        if (conflict == root)
668            break;
669
670        /* Ok, expand resource to cover the conflict, then try again .. */
671        if (conflict->start < new->start)
672            new->start = conflict->start;
673        if (conflict->end > new->end)
674            new->end = conflict->end;
675
676        printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
677    }
678    write_unlock(&resource_lock);
679}
680
681/**
682 * adjust_resource - modify a resource's start and size
683 * @res: resource to modify
684 * @start: new start value
685 * @size: new size
686 *
687 * Given an existing resource, change its start and size to match the
688 * arguments. Returns 0 on success, -EBUSY if it can't fit.
689 * Existing children of the resource are assumed to be immutable.
690 */
691int adjust_resource(struct resource *res, resource_size_t start, resource_size_t size)
692{
693    struct resource *tmp, *parent = res->parent;
694    resource_size_t end = start + size - 1;
695    int result = -EBUSY;
696
697    write_lock(&resource_lock);
698
699    if ((start < parent->start) || (end > parent->end))
700        goto out;
701
702    for (tmp = res->child; tmp; tmp = tmp->sibling) {
703        if ((tmp->start < start) || (tmp->end > end))
704            goto out;
705    }
706
707    if (res->sibling && (res->sibling->start <= end))
708        goto out;
709
710    tmp = parent->child;
711    if (tmp != res) {
712        while (tmp->sibling != res)
713            tmp = tmp->sibling;
714        if (start <= tmp->end)
715            goto out;
716    }
717
718    res->start = start;
719    res->end = end;
720    result = 0;
721
722 out:
723    write_unlock(&resource_lock);
724    return result;
725}
726
727static void __init __reserve_region_with_split(struct resource *root,
728        resource_size_t start, resource_size_t end,
729        const char *name)
730{
731    struct resource *parent = root;
732    struct resource *conflict;
733    struct resource *res = kzalloc(sizeof(*res), GFP_ATOMIC);
734
735    if (!res)
736        return;
737
738    res->name = name;
739    res->start = start;
740    res->end = end;
741    res->flags = IORESOURCE_BUSY;
742
743    conflict = __request_resource(parent, res);
744    if (!conflict)
745        return;
746
747    /* failed, split and try again */
748    kfree(res);
749
750    /* conflict covered whole area */
751    if (conflict->start <= start && conflict->end >= end)
752        return;
753
754    if (conflict->start > start)
755        __reserve_region_with_split(root, start, conflict->start-1, name);
756    if (conflict->end < end)
757        __reserve_region_with_split(root, conflict->end+1, end, name);
758}
759
760void __init reserve_region_with_split(struct resource *root,
761        resource_size_t start, resource_size_t end,
762        const char *name)
763{
764    write_lock(&resource_lock);
765    __reserve_region_with_split(root, start, end, name);
766    write_unlock(&resource_lock);
767}
768
769EXPORT_SYMBOL(adjust_resource);
770
771/**
772 * resource_alignment - calculate resource's alignment
773 * @res: resource pointer
774 *
775 * Returns alignment on success, 0 (invalid alignment) on failure.
776 */
777resource_size_t resource_alignment(struct resource *res)
778{
779    switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
780    case IORESOURCE_SIZEALIGN:
781        return resource_size(res);
782    case IORESOURCE_STARTALIGN:
783        return res->start;
784    default:
785        return 0;
786    }
787}
788
789/*
790 * This is compatibility stuff for IO resources.
791 *
792 * Note how this, unlike the above, knows about
793 * the IO flag meanings (busy etc).
794 *
795 * request_region creates a new busy region.
796 *
797 * check_region returns non-zero if the area is already busy.
798 *
799 * release_region releases a matching busy region.
800 */
801
802static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait);
803
804/**
805 * __request_region - create a new busy resource region
806 * @parent: parent resource descriptor
807 * @start: resource start address
808 * @n: resource region size
809 * @name: reserving caller's ID string
810 * @flags: IO resource flags
811 */
812struct resource * __request_region(struct resource *parent,
813                   resource_size_t start, resource_size_t n,
814                   const char *name, int flags)
815{
816    DECLARE_WAITQUEUE(wait, current);
817    struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);
818
819    if (!res)
820        return NULL;
821
822    res->name = name;
823    res->start = start;
824    res->end = start + n - 1;
825    res->flags = IORESOURCE_BUSY;
826    res->flags |= flags;
827
828    write_lock(&resource_lock);
829
830    for (;;) {
831        struct resource *conflict;
832
833        conflict = __request_resource(parent, res);
834        if (!conflict)
835            break;
836        if (conflict != parent) {
837            parent = conflict;
838            if (!(conflict->flags & IORESOURCE_BUSY))
839                continue;
840        }
841        if (conflict->flags & flags & IORESOURCE_MUXED) {
842            add_wait_queue(&muxed_resource_wait, &wait);
843            write_unlock(&resource_lock);
844            set_current_state(TASK_UNINTERRUPTIBLE);
845            schedule();
846            remove_wait_queue(&muxed_resource_wait, &wait);
847            write_lock(&resource_lock);
848            continue;
849        }
850        /* Uhhuh, that didn't work out.. */
851        kfree(res);
852        res = NULL;
853        break;
854    }
855    write_unlock(&resource_lock);
856    return res;
857}
858EXPORT_SYMBOL(__request_region);
859
860/**
861 * __check_region - check if a resource region is busy or free
862 * @parent: parent resource descriptor
863 * @start: resource start address
864 * @n: resource region size
865 *
866 * Returns 0 if the region is free at the moment it is checked,
867 * returns %-EBUSY if the region is busy.
868 *
869 * NOTE:
870 * This function is deprecated because its use is racy.
871 * Even if it returns 0, a subsequent call to request_region()
872 * may fail because another driver etc. just allocated the region.
873 * Do NOT use it. It will be removed from the kernel.
874 */
875int __check_region(struct resource *parent, resource_size_t start,
876            resource_size_t n)
877{
878    struct resource * res;
879
880    res = __request_region(parent, start, n, "check-region", 0);
881    if (!res)
882        return -EBUSY;
883
884    release_resource(res);
885    kfree(res);
886    return 0;
887}
888EXPORT_SYMBOL(__check_region);
889
890/**
891 * __release_region - release a previously reserved resource region
892 * @parent: parent resource descriptor
893 * @start: resource start address
894 * @n: resource region size
895 *
896 * The described resource region must match a currently busy region.
897 */
898void __release_region(struct resource *parent, resource_size_t start,
899            resource_size_t n)
900{
901    struct resource **p;
902    resource_size_t end;
903
904    p = &parent->child;
905    end = start + n - 1;
906
907    write_lock(&resource_lock);
908
909    for (;;) {
910        struct resource *res = *p;
911
912        if (!res)
913            break;
914        if (res->start <= start && res->end >= end) {
915            if (!(res->flags & IORESOURCE_BUSY)) {
916                p = &res->child;
917                continue;
918            }
919            if (res->start != start || res->end != end)
920                break;
921            *p = res->sibling;
922            write_unlock(&resource_lock);
923            if (res->flags & IORESOURCE_MUXED)
924                wake_up(&muxed_resource_wait);
925            kfree(res);
926            return;
927        }
928        p = &res->sibling;
929    }
930
931    write_unlock(&resource_lock);
932
933    printk(KERN_WARNING "Trying to free nonexistent resource "
934        "<%016llx-%016llx>\n", (unsigned long long)start,
935        (unsigned long long)end);
936}
937EXPORT_SYMBOL(__release_region);
938
939/*
940 * Managed region resource
941 */
942struct region_devres {
943    struct resource *parent;
944    resource_size_t start;
945    resource_size_t n;
946};
947
948static void devm_region_release(struct device *dev, void *res)
949{
950    struct region_devres *this = res;
951
952    __release_region(this->parent, this->start, this->n);
953}
954
955static int devm_region_match(struct device *dev, void *res, void *match_data)
956{
957    struct region_devres *this = res, *match = match_data;
958
959    return this->parent == match->parent &&
960        this->start == match->start && this->n == match->n;
961}
962
963struct resource * __devm_request_region(struct device *dev,
964                struct resource *parent, resource_size_t start,
965                resource_size_t n, const char *name)
966{
967    struct region_devres *dr = NULL;
968    struct resource *res;
969
970    dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
971              GFP_KERNEL);
972    if (!dr)
973        return NULL;
974
975    dr->parent = parent;
976    dr->start = start;
977    dr->n = n;
978
979    res = __request_region(parent, start, n, name, 0);
980    if (res)
981        devres_add(dev, dr);
982    else
983        devres_free(dr);
984
985    return res;
986}
987EXPORT_SYMBOL(__devm_request_region);
988
989void __devm_release_region(struct device *dev, struct resource *parent,
990               resource_size_t start, resource_size_t n)
991{
992    struct region_devres match_data = { parent, start, n };
993
994    __release_region(parent, start, n);
995    WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
996                   &match_data));
997}
998EXPORT_SYMBOL(__devm_release_region);
999
1000/*
1001 * Called from init/main.c to reserve IO ports.
1002 */
1003#define MAXRESERVE 4
1004static int __init reserve_setup(char *str)
1005{
1006    static int reserved;
1007    static struct resource reserve[MAXRESERVE];
1008
1009    for (;;) {
1010        unsigned int io_start, io_num;
1011        int x = reserved;
1012
1013        if (get_option (&str, &io_start) != 2)
1014            break;
1015        if (get_option (&str, &io_num) == 0)
1016            break;
1017        if (x < MAXRESERVE) {
1018            struct resource *res = reserve + x;
1019            res->name = "reserved";
1020            res->start = io_start;
1021            res->end = io_start + io_num - 1;
1022            res->flags = IORESOURCE_BUSY;
1023            res->child = NULL;
1024            if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
1025                reserved = x+1;
1026        }
1027    }
1028    return 1;
1029}
1030
1031__setup("reserve=", reserve_setup);
1032
1033/*
1034 * Check if the requested addr and size spans more than any slot in the
1035 * iomem resource tree.
1036 */
1037int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
1038{
1039    struct resource *p = &iomem_resource;
1040    int err = 0;
1041    loff_t l;
1042
1043    read_lock(&resource_lock);
1044    for (p = p->child; p ; p = r_next(NULL, p, &l)) {
1045        /*
1046         * We can probably skip the resources without
1047         * IORESOURCE_IO attribute?
1048         */
1049        if (p->start >= addr + size)
1050            continue;
1051        if (p->end < addr)
1052            continue;
1053        if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
1054            PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1))
1055            continue;
1056        /*
1057         * if a resource is "BUSY", it's not a hardware resource
1058         * but a driver mapping of such a resource; we don't want
1059         * to warn for those; some drivers legitimately map only
1060         * partial hardware resources. (example: vesafb)
1061         */
1062        if (p->flags & IORESOURCE_BUSY)
1063            continue;
1064
1065        printk(KERN_WARNING "resource map sanity check conflict: "
1066               "0x%llx 0x%llx 0x%llx 0x%llx %s\n",
1067               (unsigned long long)addr,
1068               (unsigned long long)(addr + size - 1),
1069               (unsigned long long)p->start,
1070               (unsigned long long)p->end,
1071               p->name);
1072        err = -1;
1073        break;
1074    }
1075    read_unlock(&resource_lock);
1076
1077    return err;
1078}
1079
1080#ifdef CONFIG_STRICT_DEVMEM
1081static int strict_iomem_checks = 1;
1082#else
1083static int strict_iomem_checks;
1084#endif
1085
1086/*
1087 * check if an address is reserved in the iomem resource tree
1088 * returns 1 if reserved, 0 if not reserved.
1089 */
1090int iomem_is_exclusive(u64 addr)
1091{
1092    struct resource *p = &iomem_resource;
1093    int err = 0;
1094    loff_t l;
1095    int size = PAGE_SIZE;
1096
1097    if (!strict_iomem_checks)
1098        return 0;
1099
1100    addr = addr & PAGE_MASK;
1101
1102    read_lock(&resource_lock);
1103    for (p = p->child; p ; p = r_next(NULL, p, &l)) {
1104        /*
1105         * We can probably skip the resources without
1106         * IORESOURCE_IO attribute?
1107         */
1108        if (p->start >= addr + size)
1109            break;
1110        if (p->end < addr)
1111            continue;
1112        if (p->flags & IORESOURCE_BUSY &&
1113             p->flags & IORESOURCE_EXCLUSIVE) {
1114            err = 1;
1115            break;
1116        }
1117    }
1118    read_unlock(&resource_lock);
1119
1120    return err;
1121}
1122
1123static int __init strict_iomem(char *str)
1124{
1125    if (strstr(str, "relaxed"))
1126        strict_iomem_checks = 0;
1127    if (strstr(str, "strict"))
1128        strict_iomem_checks = 1;
1129    return 1;
1130}
1131
1132__setup("iomem=", strict_iomem);
1133

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