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

#include <linux/config.h>
#include <linux/module.h>
#include <linux/sched.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 <asm/io.h>


struct resource ioport_resource = {
        .name   = "PCI IO",
        .start  = 0x0000,
        .end    = IO_SPACE_LIMIT,
        .flags  = IORESOURCE_IO,
};

EXPORT_SYMBOL(ioport_resource);

struct resource iomem_resource = {
        .name   = "PCI mem",
        .start  = 0UL,
        .end    = ~0UL,
        .flags  = IORESOURCE_MEM,
};

EXPORT_SYMBOL(iomem_resource);

static DEFINE_RWLOCK(resource_lock);

#ifdef CONFIG_PROC_FS

enum { MAX_IORES_LEVEL = 5 };

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;
}

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*lx-%0*lx : %s\n",
                        depth * 2, "",
                        width, r->start,
                        width, r->end,
                        r->name ? r->name : "<BAD>");
        return 0;
}

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

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

static int __init ioresources_init(void)
{
        struct proc_dir_entry *entry;

        entry = create_proc_entry("ioports", 0, NULL);
        if (entry)
                entry->proc_fops = &proc_ioports_operations;
        entry = create_proc_entry("iomem", 0, NULL);
        if (entry)
                entry->proc_fops = &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)
{
        unsigned long start = new->start;
        unsigned long 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;
}

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);

struct resource *____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;
}

EXPORT_SYMBOL(____request_resource);

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);

/*
 * Find empty slot in the resource tree given range and alignment.
 */
static int find_resource(struct resource *root, struct resource *new,
                         unsigned long size,
                         unsigned long min, unsigned long max,
                         unsigned long align,
                         void (*alignf)(void *, struct resource *,
                                        unsigned long, unsigned long),
                         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 = (new->start + align - 1) & ~(align - 1);
                if (alignf)
                        alignf(alignf_data, new, size, align);
                if (new->start < new->end && new->end - new->start + 1 >= size) {
                        new->end = new->start + size - 1;
                        return 0;
                }
                if (!this)
                        break;
                new->start = this->end + 1;
                this = this->sibling;
        }
        return -EBUSY;
}

/*
 * Allocate empty slot in the resource tree given range and alignment.
 */
int allocate_resource(struct resource *root, struct resource *new,
                      unsigned long size,
                      unsigned long min, unsigned long max,
                      unsigned long align,
                      void (*alignf)(void *, struct resource *,
                                     unsigned long, unsigned long),
                      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_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 of 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 childs of
 * the new resource.  Otherwise the new resource becomes the child of
 * the conflicting resource
 */
int insert_resource(struct resource *parent, struct resource *new)
{
        int result;
        struct resource *first, *next;

        write_lock(&resource_lock);
 begin:
        result = 0;
        first = __request_resource(parent, new);
        if (!first)
                goto out;

        result = -EBUSY;
        if (first == parent)
                goto out;

        /* Resource fully contained by the clashing resource? Recurse into it */
        if (first->start <= new->start && first->end >= new->end) {
                parent = first;
                goto begin;
        }

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

        result = 0;

        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;
        }

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

EXPORT_SYMBOL(insert_resource);

/*
 * Given an existing resource, change its start and size to match the
 * arguments.  Returns -EBUSY if it can't fit.  Existing children of
 * the resource are assumed to be immutable.
 */
int adjust_resource(struct resource *res, unsigned long start, unsigned long size)
{
        struct resource *tmp, *parent = res->parent;
        unsigned long 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;
}

EXPORT_SYMBOL(adjust_resource);

/*
 * 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.
 */
struct resource * __request_region(struct resource *parent, unsigned long start, unsigned long n, const char *name)
{
        struct resource *res = kmalloc(sizeof(*res), GFP_KERNEL);

        if (res) {
                memset(res, 0, sizeof(*res));
                res->name = name;
                res->start = start;
                res->end = start + n - 1;
                res->flags = IORESOURCE_BUSY;

                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);

int __deprecated __check_region(struct resource *parent, unsigned long start, unsigned long n)
{
        struct resource * res;

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

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

EXPORT_SYMBOL(__check_region);

void __release_region(struct resource *parent, unsigned long start, unsigned long n)
{
        struct resource **p;
        unsigned long 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 <%08lx-%08lx>\n", start, end);
}

EXPORT_SYMBOL(__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);