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
360void __weak arch_remove_reservations(struct resource *avail)
361{
362}
363
364static resource_size_t simple_align_resource(void *data,
365                         const struct resource *avail,
366                         resource_size_t size,
367                         resource_size_t align)
368{
369    return avail->start;
370}
371
372static void resource_clip(struct resource *res, resource_size_t min,
373              resource_size_t max)
374{
375    if (res->start < min)
376        res->start = min;
377    if (res->end > max)
378        res->end = max;
379}
380
381static bool resource_contains(struct resource *res1, struct resource *res2)
382{
383    return res1->start <= res2->start && res1->end >= res2->end;
384}
385
386/*
387 * Find empty slot in the resource tree given range and alignment.
388 */
389static int find_resource(struct resource *root, struct resource *new,
390             resource_size_t size, resource_size_t min,
391             resource_size_t max, resource_size_t align,
392             resource_size_t (*alignf)(void *,
393                           const struct resource *,
394                           resource_size_t,
395                           resource_size_t),
396             void *alignf_data)
397{
398    struct resource *this = root->child;
399    struct resource tmp = *new, avail, alloc;
400
401    tmp.flags = new->flags;
402    tmp.start = root->start;
403    /*
404     * Skip past an allocated resource that starts at 0, since the assignment
405     * of this->start - 1 to tmp->end below would cause an underflow.
406     */
407    if (this && this->start == 0) {
408        tmp.start = this->end + 1;
409        this = this->sibling;
410    }
411    for(;;) {
412        if (this)
413            tmp.end = this->start - 1;
414        else
415            tmp.end = root->end;
416
417        resource_clip(&tmp, min, max);
418        arch_remove_reservations(&tmp);
419
420        /* Check for overflow after ALIGN() */
421        avail = *new;
422        avail.start = ALIGN(tmp.start, align);
423        avail.end = tmp.end;
424        if (avail.start >= tmp.start) {
425            alloc.start = alignf(alignf_data, &avail, size, align);
426            alloc.end = alloc.start + size - 1;
427            if (resource_contains(&avail, &alloc)) {
428                new->start = alloc.start;
429                new->end = alloc.end;
430                return 0;
431            }
432        }
433        if (!this)
434            break;
435        tmp.start = this->end + 1;
436        this = this->sibling;
437    }
438    return -EBUSY;
439}
440
441/**
442 * allocate_resource - allocate empty slot in the resource tree given range & alignment
443 * @root: root resource descriptor
444 * @new: resource descriptor desired by caller
445 * @size: requested resource region size
446 * @min: minimum size to allocate
447 * @max: maximum size to allocate
448 * @align: alignment requested, in bytes
449 * @alignf: alignment function, optional, called if not NULL
450 * @alignf_data: arbitrary data to pass to the @alignf function
451 */
452int allocate_resource(struct resource *root, struct resource *new,
453              resource_size_t size, resource_size_t min,
454              resource_size_t max, resource_size_t align,
455              resource_size_t (*alignf)(void *,
456                        const struct resource *,
457                        resource_size_t,
458                        resource_size_t),
459              void *alignf_data)
460{
461    int err;
462
463    if (!alignf)
464        alignf = simple_align_resource;
465
466    write_lock(&resource_lock);
467    err = find_resource(root, new, size, min, max, align, alignf, alignf_data);
468    if (err >= 0 && __request_resource(root, new))
469        err = -EBUSY;
470    write_unlock(&resource_lock);
471    return err;
472}
473
474EXPORT_SYMBOL(allocate_resource);
475
476/*
477 * Insert a resource into the resource tree. If successful, return NULL,
478 * otherwise return the conflicting resource (compare to __request_resource())
479 */
480static struct resource * __insert_resource(struct resource *parent, struct resource *new)
481{
482    struct resource *first, *next;
483
484    for (;; parent = first) {
485        first = __request_resource(parent, new);
486        if (!first)
487            return first;
488
489        if (first == parent)
490            return first;
491        if (WARN_ON(first == new)) /* duplicated insertion */
492            return first;
493
494        if ((first->start > new->start) || (first->end < new->end))
495            break;
496        if ((first->start == new->start) && (first->end == new->end))
497            break;
498    }
499
500    for (next = first; ; next = next->sibling) {
501        /* Partial overlap? Bad, and unfixable */
502        if (next->start < new->start || next->end > new->end)
503            return next;
504        if (!next->sibling)
505            break;
506        if (next->sibling->start > new->end)
507            break;
508    }
509
510    new->parent = parent;
511    new->sibling = next->sibling;
512    new->child = first;
513
514    next->sibling = NULL;
515    for (next = first; next; next = next->sibling)
516        next->parent = new;
517
518    if (parent->child == first) {
519        parent->child = new;
520    } else {
521        next = parent->child;
522        while (next->sibling != first)
523            next = next->sibling;
524        next->sibling = new;
525    }
526    return NULL;
527}
528
529/**
530 * insert_resource_conflict - Inserts resource in the resource tree
531 * @parent: parent of the new resource
532 * @new: new resource to insert
533 *
534 * Returns 0 on success, conflict resource if the resource can't be inserted.
535 *
536 * This function is equivalent to request_resource_conflict when no conflict
537 * happens. If a conflict happens, and the conflicting resources
538 * entirely fit within the range of the new resource, then the new
539 * resource is inserted and the conflicting resources become children of
540 * the new resource.
541 */
542struct resource *insert_resource_conflict(struct resource *parent, struct resource *new)
543{
544    struct resource *conflict;
545
546    write_lock(&resource_lock);
547    conflict = __insert_resource(parent, new);
548    write_unlock(&resource_lock);
549    return conflict;
550}
551
552/**
553 * insert_resource - Inserts a resource in the resource tree
554 * @parent: parent of the new resource
555 * @new: new resource to insert
556 *
557 * Returns 0 on success, -EBUSY if the resource can't be inserted.
558 */
559int insert_resource(struct resource *parent, struct resource *new)
560{
561    struct resource *conflict;
562
563    conflict = insert_resource_conflict(parent, new);
564    return conflict ? -EBUSY : 0;
565}
566
567/**
568 * insert_resource_expand_to_fit - Insert a resource into the resource tree
569 * @root: root resource descriptor
570 * @new: new resource to insert
571 *
572 * Insert a resource into the resource tree, possibly expanding it in order
573 * to make it encompass any conflicting resources.
574 */
575void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
576{
577    if (new->parent)
578        return;
579
580    write_lock(&resource_lock);
581    for (;;) {
582        struct resource *conflict;
583
584        conflict = __insert_resource(root, new);
585        if (!conflict)
586            break;
587        if (conflict == root)
588            break;
589
590        /* Ok, expand resource to cover the conflict, then try again .. */
591        if (conflict->start < new->start)
592            new->start = conflict->start;
593        if (conflict->end > new->end)
594            new->end = conflict->end;
595
596        printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
597    }
598    write_unlock(&resource_lock);
599}
600
601/**
602 * adjust_resource - modify a resource's start and size
603 * @res: resource to modify
604 * @start: new start value
605 * @size: new size
606 *
607 * Given an existing resource, change its start and size to match the
608 * arguments. Returns 0 on success, -EBUSY if it can't fit.
609 * Existing children of the resource are assumed to be immutable.
610 */
611int adjust_resource(struct resource *res, resource_size_t start, resource_size_t size)
612{
613    struct resource *tmp, *parent = res->parent;
614    resource_size_t end = start + size - 1;
615    int result = -EBUSY;
616
617    write_lock(&resource_lock);
618
619    if ((start < parent->start) || (end > parent->end))
620        goto out;
621
622    for (tmp = res->child; tmp; tmp = tmp->sibling) {
623        if ((tmp->start < start) || (tmp->end > end))
624            goto out;
625    }
626
627    if (res->sibling && (res->sibling->start <= end))
628        goto out;
629
630    tmp = parent->child;
631    if (tmp != res) {
632        while (tmp->sibling != res)
633            tmp = tmp->sibling;
634        if (start <= tmp->end)
635            goto out;
636    }
637
638    res->start = start;
639    res->end = end;
640    result = 0;
641
642 out:
643    write_unlock(&resource_lock);
644    return result;
645}
646
647static void __init __reserve_region_with_split(struct resource *root,
648        resource_size_t start, resource_size_t end,
649        const char *name)
650{
651    struct resource *parent = root;
652    struct resource *conflict;
653    struct resource *res = kzalloc(sizeof(*res), GFP_ATOMIC);
654
655    if (!res)
656        return;
657
658    res->name = name;
659    res->start = start;
660    res->end = end;
661    res->flags = IORESOURCE_BUSY;
662
663    conflict = __request_resource(parent, res);
664    if (!conflict)
665        return;
666
667    /* failed, split and try again */
668    kfree(res);
669
670    /* conflict covered whole area */
671    if (conflict->start <= start && conflict->end >= end)
672        return;
673
674    if (conflict->start > start)
675        __reserve_region_with_split(root, start, conflict->start-1, name);
676    if (conflict->end < end)
677        __reserve_region_with_split(root, conflict->end+1, end, name);
678}
679
680void __init reserve_region_with_split(struct resource *root,
681        resource_size_t start, resource_size_t end,
682        const char *name)
683{
684    write_lock(&resource_lock);
685    __reserve_region_with_split(root, start, end, name);
686    write_unlock(&resource_lock);
687}
688
689EXPORT_SYMBOL(adjust_resource);
690
691/**
692 * resource_alignment - calculate resource's alignment
693 * @res: resource pointer
694 *
695 * Returns alignment on success, 0 (invalid alignment) on failure.
696 */
697resource_size_t resource_alignment(struct resource *res)
698{
699    switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
700    case IORESOURCE_SIZEALIGN:
701        return resource_size(res);
702    case IORESOURCE_STARTALIGN:
703        return res->start;
704    default:
705        return 0;
706    }
707}
708
709/*
710 * This is compatibility stuff for IO resources.
711 *
712 * Note how this, unlike the above, knows about
713 * the IO flag meanings (busy etc).
714 *
715 * request_region creates a new busy region.
716 *
717 * check_region returns non-zero if the area is already busy.
718 *
719 * release_region releases a matching busy region.
720 */
721
722static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait);
723
724/**
725 * __request_region - create a new busy resource region
726 * @parent: parent resource descriptor
727 * @start: resource start address
728 * @n: resource region size
729 * @name: reserving caller's ID string
730 * @flags: IO resource flags
731 */
732struct resource * __request_region(struct resource *parent,
733                   resource_size_t start, resource_size_t n,
734                   const char *name, int flags)
735{
736    DECLARE_WAITQUEUE(wait, current);
737    struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);
738
739    if (!res)
740        return NULL;
741
742    res->name = name;
743    res->start = start;
744    res->end = start + n - 1;
745    res->flags = IORESOURCE_BUSY;
746    res->flags |= flags;
747
748    write_lock(&resource_lock);
749
750    for (;;) {
751        struct resource *conflict;
752
753        conflict = __request_resource(parent, res);
754        if (!conflict)
755            break;
756        if (conflict != parent) {
757            parent = conflict;
758            if (!(conflict->flags & IORESOURCE_BUSY))
759                continue;
760        }
761        if (conflict->flags & flags & IORESOURCE_MUXED) {
762            add_wait_queue(&muxed_resource_wait, &wait);
763            write_unlock(&resource_lock);
764            set_current_state(TASK_UNINTERRUPTIBLE);
765            schedule();
766            remove_wait_queue(&muxed_resource_wait, &wait);
767            write_lock(&resource_lock);
768            continue;
769        }
770        /* Uhhuh, that didn't work out.. */
771        kfree(res);
772        res = NULL;
773        break;
774    }
775    write_unlock(&resource_lock);
776    return res;
777}
778EXPORT_SYMBOL(__request_region);
779
780/**
781 * __check_region - check if a resource region is busy or free
782 * @parent: parent resource descriptor
783 * @start: resource start address
784 * @n: resource region size
785 *
786 * Returns 0 if the region is free at the moment it is checked,
787 * returns %-EBUSY if the region is busy.
788 *
789 * NOTE:
790 * This function is deprecated because its use is racy.
791 * Even if it returns 0, a subsequent call to request_region()
792 * may fail because another driver etc. just allocated the region.
793 * Do NOT use it. It will be removed from the kernel.
794 */
795int __check_region(struct resource *parent, resource_size_t start,
796            resource_size_t n)
797{
798    struct resource * res;
799
800    res = __request_region(parent, start, n, "check-region", 0);
801    if (!res)
802        return -EBUSY;
803
804    release_resource(res);
805    kfree(res);
806    return 0;
807}
808EXPORT_SYMBOL(__check_region);
809
810/**
811 * __release_region - release a previously reserved resource region
812 * @parent: parent resource descriptor
813 * @start: resource start address
814 * @n: resource region size
815 *
816 * The described resource region must match a currently busy region.
817 */
818void __release_region(struct resource *parent, resource_size_t start,
819            resource_size_t n)
820{
821    struct resource **p;
822    resource_size_t end;
823
824    p = &parent->child;
825    end = start + n - 1;
826
827    write_lock(&resource_lock);
828
829    for (;;) {
830        struct resource *res = *p;
831
832        if (!res)
833            break;
834        if (res->start <= start && res->end >= end) {
835            if (!(res->flags & IORESOURCE_BUSY)) {
836                p = &res->child;
837                continue;
838            }
839            if (res->start != start || res->end != end)
840                break;
841            *p = res->sibling;
842            write_unlock(&resource_lock);
843            if (res->flags & IORESOURCE_MUXED)
844                wake_up(&muxed_resource_wait);
845            kfree(res);
846            return;
847        }
848        p = &res->sibling;
849    }
850
851    write_unlock(&resource_lock);
852
853    printk(KERN_WARNING "Trying to free nonexistent resource "
854        "<%016llx-%016llx>\n", (unsigned long long)start,
855        (unsigned long long)end);
856}
857EXPORT_SYMBOL(__release_region);
858
859/*
860 * Managed region resource
861 */
862struct region_devres {
863    struct resource *parent;
864    resource_size_t start;
865    resource_size_t n;
866};
867
868static void devm_region_release(struct device *dev, void *res)
869{
870    struct region_devres *this = res;
871
872    __release_region(this->parent, this->start, this->n);
873}
874
875static int devm_region_match(struct device *dev, void *res, void *match_data)
876{
877    struct region_devres *this = res, *match = match_data;
878
879    return this->parent == match->parent &&
880        this->start == match->start && this->n == match->n;
881}
882
883struct resource * __devm_request_region(struct device *dev,
884                struct resource *parent, resource_size_t start,
885                resource_size_t n, const char *name)
886{
887    struct region_devres *dr = NULL;
888    struct resource *res;
889
890    dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
891              GFP_KERNEL);
892    if (!dr)
893        return NULL;
894
895    dr->parent = parent;
896    dr->start = start;
897    dr->n = n;
898
899    res = __request_region(parent, start, n, name, 0);
900    if (res)
901        devres_add(dev, dr);
902    else
903        devres_free(dr);
904
905    return res;
906}
907EXPORT_SYMBOL(__devm_request_region);
908
909void __devm_release_region(struct device *dev, struct resource *parent,
910               resource_size_t start, resource_size_t n)
911{
912    struct region_devres match_data = { parent, start, n };
913
914    __release_region(parent, start, n);
915    WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
916                   &match_data));
917}
918EXPORT_SYMBOL(__devm_release_region);
919
920/*
921 * Called from init/main.c to reserve IO ports.
922 */
923#define MAXRESERVE 4
924static int __init reserve_setup(char *str)
925{
926    static int reserved;
927    static struct resource reserve[MAXRESERVE];
928
929    for (;;) {
930        unsigned int io_start, io_num;
931        int x = reserved;
932
933        if (get_option (&str, &io_start) != 2)
934            break;
935        if (get_option (&str, &io_num) == 0)
936            break;
937        if (x < MAXRESERVE) {
938            struct resource *res = reserve + x;
939            res->name = "reserved";
940            res->start = io_start;
941            res->end = io_start + io_num - 1;
942            res->flags = IORESOURCE_BUSY;
943            res->child = NULL;
944            if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
945                reserved = x+1;
946        }
947    }
948    return 1;
949}
950
951__setup("reserve=", reserve_setup);
952
953/*
954 * Check if the requested addr and size spans more than any slot in the
955 * iomem resource tree.
956 */
957int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
958{
959    struct resource *p = &iomem_resource;
960    int err = 0;
961    loff_t l;
962
963    read_lock(&resource_lock);
964    for (p = p->child; p ; p = r_next(NULL, p, &l)) {
965        /*
966         * We can probably skip the resources without
967         * IORESOURCE_IO attribute?
968         */
969        if (p->start >= addr + size)
970            continue;
971        if (p->end < addr)
972            continue;
973        if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
974            PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1))
975            continue;
976        /*
977         * if a resource is "BUSY", it's not a hardware resource
978         * but a driver mapping of such a resource; we don't want
979         * to warn for those; some drivers legitimately map only
980         * partial hardware resources. (example: vesafb)
981         */
982        if (p->flags & IORESOURCE_BUSY)
983            continue;
984
985        printk(KERN_WARNING "resource map sanity check conflict: "
986               "0x%llx 0x%llx 0x%llx 0x%llx %s\n",
987               (unsigned long long)addr,
988               (unsigned long long)(addr + size - 1),
989               (unsigned long long)p->start,
990               (unsigned long long)p->end,
991               p->name);
992        err = -1;
993        break;
994    }
995    read_unlock(&resource_lock);
996
997    return err;
998}
999
1000#ifdef CONFIG_STRICT_DEVMEM
1001static int strict_iomem_checks = 1;
1002#else
1003static int strict_iomem_checks;
1004#endif
1005
1006/*
1007 * check if an address is reserved in the iomem resource tree
1008 * returns 1 if reserved, 0 if not reserved.
1009 */
1010int iomem_is_exclusive(u64 addr)
1011{
1012    struct resource *p = &iomem_resource;
1013    int err = 0;
1014    loff_t l;
1015    int size = PAGE_SIZE;
1016
1017    if (!strict_iomem_checks)
1018        return 0;
1019
1020    addr = addr & PAGE_MASK;
1021
1022    read_lock(&resource_lock);
1023    for (p = p->child; p ; p = r_next(NULL, p, &l)) {
1024        /*
1025         * We can probably skip the resources without
1026         * IORESOURCE_IO attribute?
1027         */
1028        if (p->start >= addr + size)
1029            break;
1030        if (p->end < addr)
1031            continue;
1032        if (p->flags & IORESOURCE_BUSY &&
1033             p->flags & IORESOURCE_EXCLUSIVE) {
1034            err = 1;
1035            break;
1036        }
1037    }
1038    read_unlock(&resource_lock);
1039
1040    return err;
1041}
1042
1043static int __init strict_iomem(char *str)
1044{
1045    if (strstr(str, "relaxed"))
1046        strict_iomem_checks = 0;
1047    if (strstr(str, "strict"))
1048        strict_iomem_checks = 1;
1049    return 1;
1050}
1051
1052__setup("iomem=", strict_iomem);
1053

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