resource.c

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/*
 *      linux/kernel/resource.c
 *
 * Copyright (C) 1999   Linus Torvalds
 * Copyright (C) 1999   Martin Mares <mj@ucw.cz>
 *
 * Arbitrary resource management.
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/fs.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/device.h>
#include <linux/pfn.h>
#include <asm/io.h>


struct resource ioport_resource = {
        .name   = "PCI IO",
        .start  = 0,
        .end    = IO_SPACE_LIMIT,
        .flags  = IORESOURCE_IO,
};
EXPORT_SYMBOL(ioport_resource);

struct resource iomem_resource = {
        .name   = "PCI mem",
        .start  = 0,
        .end    = -1,
        .flags  = IORESOURCE_MEM,
};
EXPORT_SYMBOL(iomem_resource);

static DEFINE_RWLOCK(resource_lock);

static void *r_next(struct seq_file *m, void *v, loff_t *pos)
{
        struct resource *p = v;
        (*pos)++;
        if (p->child)
                return p->child;
        while (!p->sibling && p->parent)
                p = p->parent;
        return p->sibling;
}

#ifdef CONFIG_PROC_FS

enum { MAX_IORES_LEVEL = 5 };

static void *r_start(struct seq_file *m, loff_t *pos)
        __acquires(resource_lock)
{
        struct resource *p = m->private;
        loff_t l = 0;
        read_lock(&resource_lock);
        for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
                ;
        return p;
}

static void r_stop(struct seq_file *m, void *v)
        __releases(resource_lock)
{
        read_unlock(&resource_lock);
}

static int r_show(struct seq_file *m, void *v)
{
        struct resource *root = m->private;
        struct resource *r = v, *p;
        int width = root->end < 0x10000 ? 4 : 8;
        int depth;

        for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
                if (p->parent == root)
                        break;
        seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
                        depth * 2, "",
                        width, (unsigned long long) r->start,
                        width, (unsigned long long) r->end,
                        r->name ? r->name : "<BAD>");
        return 0;
}

static const struct seq_operations resource_op = {
        .start  = r_start,
        .next   = r_next,
        .stop   = r_stop,
        .show   = r_show,
};

static int ioports_open(struct inode *inode, struct file *file)
{
        int res = seq_open(file, &resource_op);
        if (!res) {
                struct seq_file *m = file->private_data;
                m->private = &ioport_resource;
        }
        return res;
}

static int iomem_open(struct inode *inode, struct file *file)
{
        int res = seq_open(file, &resource_op);
        if (!res) {
                struct seq_file *m = file->private_data;
                m->private = &iomem_resource;
        }
        return res;
}

static const struct file_operations proc_ioports_operations = {
        .open           = ioports_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = seq_release,
};

static const struct file_operations proc_iomem_operations = {
        .open           = iomem_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = seq_release,
};

static int __init ioresources_init(void)
{
        proc_create("ioports", 0, NULL, &proc_ioports_operations);
        proc_create("iomem", 0, NULL, &proc_iomem_operations);
        return 0;
}
__initcall(ioresources_init);

#endif /* CONFIG_PROC_FS */

/* Return the conflict entry if you can't request it */
static struct resource * __request_resource(struct resource *root, struct resource *new)
{
        resource_size_t start = new->start;
        resource_size_t end = new->end;
        struct resource *tmp, **p;

        if (end < start)
                return root;
        if (start < root->start)
                return root;
        if (end > root->end)
                return root;
        p = &root->child;
        for (;;) {
                tmp = *p;
                if (!tmp || tmp->start > end) {
                        new->sibling = tmp;
                        *p = new;
                        new->parent = root;
                        return NULL;
                }
                p = &tmp->sibling;
                if (tmp->end < start)
                        continue;
                return tmp;
        }
}

static int __release_resource(struct resource *old)
{
        struct resource *tmp, **p;

        p = &old->parent->child;
        for (;;) {
                tmp = *p;
                if (!tmp)
                        break;
                if (tmp == old) {
                        *p = tmp->sibling;
                        old->parent = NULL;
                        return 0;
                }
                p = &tmp->sibling;
        }
        return -EINVAL;
}

/**
 * request_resource - request and reserve an I/O or memory resource
 * @root: root resource descriptor
 * @new: resource descriptor desired by caller
 *
 * Returns 0 for success, negative error code on error.
 */
int request_resource(struct resource *root, struct resource *new)
{
        struct resource *conflict;

        write_lock(&resource_lock);
        conflict = __request_resource(root, new);
        write_unlock(&resource_lock);
        return conflict ? -EBUSY : 0;
}

EXPORT_SYMBOL(request_resource);

/**
 * release_resource - release a previously reserved resource
 * @old: resource pointer
 */
int release_resource(struct resource *old)
{
        int retval;

        write_lock(&resource_lock);
        retval = __release_resource(old);
        write_unlock(&resource_lock);
        return retval;
}

EXPORT_SYMBOL(release_resource);

#if defined(CONFIG_MEMORY_HOTPLUG) && !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
/*
 * Finds the lowest memory reosurce exists within [res->start.res->end)
 * the caller must specify res->start, res->end, res->flags.
 * If found, returns 0, res is overwritten, if not found, returns -1.
 */
static int find_next_system_ram(struct resource *res)
{
        resource_size_t start, end;
        struct resource *p;

        BUG_ON(!res);

        start = res->start;
        end = res->end;
        BUG_ON(start >= end);

        read_lock(&resource_lock);
        for (p = iomem_resource.child; p ; p = p->sibling) {
                /* system ram is just marked as IORESOURCE_MEM */
                if (p->flags != res->flags)
                        continue;
                if (p->start > end) {
                        p = NULL;
                        break;
                }
                if ((p->end >= start) && (p->start < end))
                        break;
        }
        read_unlock(&resource_lock);
        if (!p)
                return -1;
        /* copy data */
        if (res->start < p->start)
                res->start = p->start;
        if (res->end > p->end)
                res->end = p->end;
        return 0;
}
int
walk_memory_resource(unsigned long start_pfn, unsigned long nr_pages, void *arg,
                        int (*func)(unsigned long, unsigned long, void *))
{
        struct resource res;
        unsigned long pfn, len;
        u64 orig_end;
        int ret = -1;
        res.start = (u64) start_pfn << PAGE_SHIFT;
        res.end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
        res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
        orig_end = res.end;
        while ((res.start < res.end) && (find_next_system_ram(&res) >= 0)) {
                pfn = (unsigned long)(res.start >> PAGE_SHIFT);
                len = (unsigned long)((res.end + 1 - res.start) >> PAGE_SHIFT);
                ret = (*func)(pfn, len, arg);
                if (ret)
                        break;
                res.start = res.end + 1;
                res.end = orig_end;
        }
        return ret;
}

#endif

/*
 * Find empty slot in the resource tree given range and alignment.
 */
static int find_resource(struct resource *root, struct resource *new,
                         resource_size_t size, resource_size_t min,
                         resource_size_t max, resource_size_t align,
                         void (*alignf)(void *, struct resource *,
                                        resource_size_t, resource_size_t),
                         void *alignf_data)
{
        struct resource *this = root->child;

        new->start = root->start;
        /*
         * Skip past an allocated resource that starts at 0, since the assignment
         * of this->start - 1 to new->end below would cause an underflow.
         */
        if (this && this->start == 0) {
                new->start = this->end + 1;
                this = this->sibling;
        }
        for(;;) {
                if (this)
                        new->end = this->start - 1;
                else
                        new->end = root->end;
                if (new->start < min)
                        new->start = min;
                if (new->end > max)
                        new->end = max;
                new->start = ALIGN(new->start, align);
                if (alignf)
                        alignf(alignf_data, new, size, align);
                if (new->start < new->end && new->end - new->start >= size - 1) {
                        new->end = new->start + size - 1;
                        return 0;
                }
                if (!this)
                        break;
                new->start = this->end + 1;
                this = this->sibling;
        }
        return -EBUSY;
}

/**
 * allocate_resource - allocate empty slot in the resource tree given range & alignment
 * @root: root resource descriptor
 * @new: resource descriptor desired by caller
 * @size: requested resource region size
 * @min: minimum size to allocate
 * @max: maximum size to allocate
 * @align: alignment requested, in bytes
 * @alignf: alignment function, optional, called if not NULL
 * @alignf_data: arbitrary data to pass to the @alignf function
 */
int allocate_resource(struct resource *root, struct resource *new,
                      resource_size_t size, resource_size_t min,
                      resource_size_t max, resource_size_t align,
                      void (*alignf)(void *, struct resource *,
                                     resource_size_t, resource_size_t),
                      void *alignf_data)
{
        int err;

        write_lock(&resource_lock);
        err = find_resource(root, new, size, min, max, align, alignf, alignf_data);
        if (err >= 0 && __request_resource(root, new))
                err = -EBUSY;
        write_unlock(&resource_lock);
        return err;
}

EXPORT_SYMBOL(allocate_resource);

/*
 * Insert a resource into the resource tree. If successful, return NULL,
 * otherwise return the conflicting resource (compare to __request_resource())
 */
static struct resource * __insert_resource(struct resource *parent, struct resource *new)
{
        struct resource *first, *next;

        for (;; parent = first) {
                first = __request_resource(parent, new);
                if (!first)
                        return first;

                if (first == parent)
                        return first;

                if ((first->start > new->start) || (first->end < new->end))
                        break;
                if ((first->start == new->start) && (first->end == new->end))
                        break;
        }

        for (next = first; ; next = next->sibling) {
                /* Partial overlap? Bad, and unfixable */
                if (next->start < new->start || next->end > new->end)
                        return next;
                if (!next->sibling)
                        break;
                if (next->sibling->start > new->end)
                        break;
        }

        new->parent = parent;
        new->sibling = next->sibling;
        new->child = first;

        next->sibling = NULL;
        for (next = first; next; next = next->sibling)
                next->parent = new;

        if (parent->child == first) {
                parent->child = new;
        } else {
                next = parent->child;
                while (next->sibling != first)
                        next = next->sibling;
                next->sibling = new;
        }
        return NULL;
}

/**
 * insert_resource - Inserts a resource in the resource tree
 * @parent: parent of the new resource
 * @new: new resource to insert
 *
 * Returns 0 on success, -EBUSY if the resource can't be inserted.
 *
 * This function is equivalent to request_resource when no conflict
 * happens. If a conflict happens, and the conflicting resources
 * entirely fit within the range of the new resource, then the new
 * resource is inserted and the conflicting resources become children of
 * the new resource.
 */
int insert_resource(struct resource *parent, struct resource *new)
{
        struct resource *conflict;

        write_lock(&resource_lock);
        conflict = __insert_resource(parent, new);
        write_unlock(&resource_lock);
        return conflict ? -EBUSY : 0;
}

/**
 * insert_resource_expand_to_fit - Insert a resource into the resource tree
 * @root: root resource descriptor
 * @new: new resource to insert
 *
 * Insert a resource into the resource tree, possibly expanding it in order
 * to make it encompass any conflicting resources.
 */
void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
{
        if (new->parent)
                return;

        write_lock(&resource_lock);
        for (;;) {
                struct resource *conflict;

                conflict = __insert_resource(root, new);
                if (!conflict)
                        break;
                if (conflict == root)
                        break;

                /* Ok, expand resource to cover the conflict, then try again .. */
                if (conflict->start < new->start)
                        new->start = conflict->start;
                if (conflict->end > new->end)
                        new->end = conflict->end;

                printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
        }
        write_unlock(&resource_lock);
}

/**
 * adjust_resource - modify a resource's start and size
 * @res: resource to modify
 * @start: new start value
 * @size: new size
 *
 * Given an existing resource, change its start and size to match the
 * arguments.  Returns 0 on success, -EBUSY if it can't fit.
 * Existing children of the resource are assumed to be immutable.
 */
int adjust_resource(struct resource *res, resource_size_t start, resource_size_t size)
{
        struct resource *tmp, *parent = res->parent;
        resource_size_t end = start + size - 1;
        int result = -EBUSY;

        write_lock(&resource_lock);

        if ((start < parent->start) || (end > parent->end))
                goto out;

        for (tmp = res->child; tmp; tmp = tmp->sibling) {
                if ((tmp->start < start) || (tmp->end > end))
                        goto out;
        }

        if (res->sibling && (res->sibling->start <= end))
                goto out;

        tmp = parent->child;
        if (tmp != res) {
                while (tmp->sibling != res)
                        tmp = tmp->sibling;
                if (start <= tmp->end)
                        goto out;
        }

        res->start = start;
        res->end = end;
        result = 0;

 out:
        write_unlock(&resource_lock);
        return result;
}

static void __init __reserve_region_with_split(struct resource *root,
                resource_size_t start, resource_size_t end,
                const char *name)
{
        struct resource *parent = root;
        struct resource *conflict;
        struct resource *res = kzalloc(sizeof(*res), GFP_ATOMIC);

        if (!res)
                return;

        res->name = name;
        res->start = start;
        res->end = end;
        res->flags = IORESOURCE_BUSY;

        for (;;) {
                conflict = __request_resource(parent, res);
                if (!conflict)
                        break;
                if (conflict != parent) {
                        parent = conflict;
                        if (!(conflict->flags & IORESOURCE_BUSY))
                                continue;
                }

                /* Uhhuh, that didn't work out.. */
                kfree(res);
                res = NULL;
                break;
        }

        if (!res) {
                /* failed, split and try again */

                /* conflict covered whole area */
                if (conflict->start <= start && conflict->end >= end)
                        return;

                if (conflict->start > start)
                        __reserve_region_with_split(root, start, conflict->start-1, name);
                if (!(conflict->flags & IORESOURCE_BUSY)) {
                        resource_size_t common_start, common_end;

                        common_start = max(conflict->start, start);
                        common_end = min(conflict->end, end);
                        if (common_start < common_end)
                                __reserve_region_with_split(root, common_start, common_end, name);
                }
                if (conflict->end < end)
                        __reserve_region_with_split(root, conflict->end+1, end, name);
        }

}

void __init reserve_region_with_split(struct resource *root,
                resource_size_t start, resource_size_t end,
                const char *name)
{
        write_lock(&resource_lock);
        __reserve_region_with_split(root, start, end, name);
        write_unlock(&resource_lock);
}

EXPORT_SYMBOL(adjust_resource);

/**
 * resource_alignment - calculate resource's alignment
 * @res: resource pointer
 *
 * Returns alignment on success, 0 (invalid alignment) on failure.
 */
resource_size_t resource_alignment(struct resource *res)
{
        switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
        case IORESOURCE_SIZEALIGN:
                return resource_size(res);
        case IORESOURCE_STARTALIGN:
                return res->start;
        default:
                return 0;
        }
}

/*
 * This is compatibility stuff for IO resources.
 *
 * Note how this, unlike the above, knows about
 * the IO flag meanings (busy etc).
 *
 * request_region creates a new busy region.
 *
 * check_region returns non-zero if the area is already busy.
 *
 * release_region releases a matching busy region.
 */

#ifndef DDE_LINUX
/**
 * __request_region - create a new busy resource region
 * @parent: parent resource descriptor
 * @start: resource start address
 * @n: resource region size
 * @name: reserving caller's ID string
 * @flags: IO resource flags
 */
struct resource * __request_region(struct resource *parent,
                                   resource_size_t start, resource_size_t n,
                                   const char *name, int flags)
{
        struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);

        if (!res)
                return NULL;

        res->name = name;
        res->start = start;
        res->end = start + n - 1;
        res->flags = IORESOURCE_BUSY;
        res->flags |= flags;

        write_lock(&resource_lock);

        for (;;) {
                struct resource *conflict;

                conflict = __request_resource(parent, res);
                if (!conflict)
                        break;
                if (conflict != parent) {
                        parent = conflict;
                        if (!(conflict->flags & IORESOURCE_BUSY))
                                continue;
                }

                /* Uhhuh, that didn't work out.. */
                kfree(res);
                res = NULL;
                break;
        }
        write_unlock(&resource_lock);
        return res;
}
EXPORT_SYMBOL(__request_region);

/**
 * __check_region - check if a resource region is busy or free
 * @parent: parent resource descriptor
 * @start: resource start address
 * @n: resource region size
 *
 * Returns 0 if the region is free at the moment it is checked,
 * returns %-EBUSY if the region is busy.
 *
 * NOTE:
 * This function is deprecated because its use is racy.
 * Even if it returns 0, a subsequent call to request_region()
 * may fail because another driver etc. just allocated the region.
 * Do NOT use it.  It will be removed from the kernel.
 */
int __check_region(struct resource *parent, resource_size_t start,
                        resource_size_t n)
{
        struct resource * res;

        res = __request_region(parent, start, n, "check-region", 0);
        if (!res)
                return -EBUSY;

        release_resource(res);
        kfree(res);
        return 0;
}
EXPORT_SYMBOL(__check_region);

/**
 * __release_region - release a previously reserved resource region
 * @parent: parent resource descriptor
 * @start: resource start address
 * @n: resource region size
 *
 * The described resource region must match a currently busy region.
 */
void __release_region(struct resource *parent, resource_size_t start,
                        resource_size_t n)
{
        struct resource **p;
        resource_size_t end;

        p = &parent->child;
        end = start + n - 1;

        write_lock(&resource_lock);

        for (;;) {
                struct resource *res = *p;

                if (!res)
                        break;
                if (res->start <= start && res->end >= end) {
                        if (!(res->flags & IORESOURCE_BUSY)) {
                                p = &res->child;
                                continue;
                        }
                        if (res->start != start || res->end != end)
                                break;
                        *p = res->sibling;
                        write_unlock(&resource_lock);
                        kfree(res);
                        return;
                }
                p = &res->sibling;
        }

        write_unlock(&resource_lock);

        printk(KERN_WARNING "Trying to free nonexistent resource "
                "<%016llx-%016llx>\n", (unsigned long long)start,
                (unsigned long long)end);
}
EXPORT_SYMBOL(__release_region);
#endif /* DDE_LINUX */

/*
 * Managed region resource
 */
struct region_devres {
        struct resource *parent;
        resource_size_t start;
        resource_size_t n;
};

static void devm_region_release(struct device *dev, void *res)
{
        struct region_devres *this = res;

        __release_region(this->parent, this->start, this->n);
}

static int devm_region_match(struct device *dev, void *res, void *match_data)
{
        struct region_devres *this = res, *match = match_data;

        return this->parent == match->parent &&
                this->start == match->start && this->n == match->n;
}

struct resource * __devm_request_region(struct device *dev,
                                struct resource *parent, resource_size_t start,
                                resource_size_t n, const char *name)
{
        struct region_devres *dr = NULL;
        struct resource *res;

        dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
                          GFP_KERNEL);
        if (!dr)
                return NULL;

        dr->parent = parent;
        dr->start = start;
        dr->n = n;

        res = __request_region(parent, start, n, name, 0);
        if (res)
                devres_add(dev, dr);
        else
                devres_free(dr);

        return res;
}
EXPORT_SYMBOL(__devm_request_region);

void __devm_release_region(struct device *dev, struct resource *parent,
                           resource_size_t start, resource_size_t n)
{
        struct region_devres match_data = { parent, start, n };

        __release_region(parent, start, n);
        WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
                               &match_data));
}
EXPORT_SYMBOL(__devm_release_region);

/*
 * Called from init/main.c to reserve IO ports.
 */
#define MAXRESERVE 4
static int __init reserve_setup(char *str)
{
        static int reserved;
        static struct resource reserve[MAXRESERVE];

        for (;;) {
                int io_start, io_num;
                int x = reserved;

                if (get_option (&str, &io_start) != 2)
                        break;
                if (get_option (&str, &io_num)   == 0)
                        break;
                if (x < MAXRESERVE) {
                        struct resource *res = reserve + x;
                        res->name = "reserved";
                        res->start = io_start;
                        res->end = io_start + io_num - 1;
                        res->flags = IORESOURCE_BUSY;
                        res->child = NULL;
                        if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
                                reserved = x+1;
                }
        }
        return 1;
}

__setup("reserve=", reserve_setup);

/*
 * Check if the requested addr and size spans more than any slot in the
 * iomem resource tree.
 */
int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
{
        struct resource *p = &iomem_resource;
        int err = 0;
        loff_t l;

        read_lock(&resource_lock);
        for (p = p->child; p ; p = r_next(NULL, p, &l)) {
                /*
                 * We can probably skip the resources without
                 * IORESOURCE_IO attribute?
                 */
                if (p->start >= addr + size)
                        continue;
                if (p->end < addr)
                        continue;
                if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
                    PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1))
                        continue;
                /*
                 * if a resource is "BUSY", it's not a hardware resource
                 * but a driver mapping of such a resource; we don't want
                 * to warn for those; some drivers legitimately map only
                 * partial hardware resources. (example: vesafb)
                 */
                if (p->flags & IORESOURCE_BUSY)
                        continue;

                printk(KERN_WARNING "resource map sanity check conflict: "
                       "0x%llx 0x%llx 0x%llx 0x%llx %s\n",
                       (unsigned long long)addr,
                       (unsigned long long)(addr + size - 1),
                       (unsigned long long)p->start,
                       (unsigned long long)p->end,
                       p->name);
                err = -1;
                break;
        }
        read_unlock(&resource_lock);

        return err;
}

#ifdef CONFIG_STRICT_DEVMEM
static int strict_iomem_checks = 1;
#else
static int strict_iomem_checks;
#endif

/*
 * check if an address is reserved in the iomem resource tree
 * returns 1 if reserved, 0 if not reserved.
 */
int iomem_is_exclusive(u64 addr)
{
        struct resource *p = &iomem_resource;
        int err = 0;
        loff_t l;
        int size = PAGE_SIZE;

        if (!strict_iomem_checks)
                return 0;

        addr = addr & PAGE_MASK;

        read_lock(&resource_lock);
        for (p = p->child; p ; p = r_next(NULL, p, &l)) {
                /*
                 * We can probably skip the resources without
                 * IORESOURCE_IO attribute?
                 */
                if (p->start >= addr + size)
                        break;
                if (p->end < addr)
                        continue;
                if (p->flags & IORESOURCE_BUSY &&
                     p->flags & IORESOURCE_EXCLUSIVE) {
                        err = 1;
                        break;
                }
        }
        read_unlock(&resource_lock);

        return err;
}

static int __init strict_iomem(char *str)
{
        if (strstr(str, "relaxed"))
                strict_iomem_checks = 0;
        if (strstr(str, "strict"))
                strict_iomem_checks = 1;
        return 1;
}

__setup("iomem=", strict_iomem);

---