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

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