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/*
 * resource.c - barebox resource management
 *
 * Copyright (c) 2011 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation.
 */
#include <common.h>
#include <malloc.h>
#include <errno.h>
#include <init.h>
#include <linux/ioport.h>

static int init_resource(struct resource *res, const char *name)
{
	INIT_LIST_HEAD(&res->children);
	res->parent = NULL;
	res->name = xstrdup(name);

	return 0;
}

/*
 * request a region.
 * This will succedd when the requested region is completely inside
 * the parent resource and does not conflict with any of the child
 * resources.
 */
struct resource *request_region(struct resource *parent,
		const char *name, resource_size_t start,
		resource_size_t size)
{
	struct resource *r, *new;

	/* outside parent resource? */
	if (start < parent->start ||
			start + size > parent->start + parent->size) {
		debug("%s: 0x%08x:0x%08x outside parent resource 0x%08x:0x%08x\n",
				__func__, start, size, parent->start,
				parent->size);
		return NULL;
	}

	/*
	 * We keep the list of child resources ordered which helps
	 * us searching for conflicts here.
	 */
	list_for_each_entry(r, &parent->children, sibling) {
		if (start + size <= r->start)
			goto ok;
		if (start >= r->start + r->size)
			continue;
		debug("%s: 0x%08x:0x%08x conflicts with 0x%08x:0x%08x\n",
				__func__, start, size, r->start, r->size);
		return NULL;
	}

ok:
	debug("%s ok: 0x%08x 0x%08x\n", __func__, start, size);

	new = xzalloc(sizeof(*new));
	init_resource(new, name);
	new->start = start;
	new->size = size;
	new->parent = parent;
	list_add_tail(&new->sibling, &r->sibling);

	return new;
}

/*
 * release a region previously requested with request_region
 */
int release_region(struct resource *res)
{
	if (!list_empty(&res->children))
		return -EBUSY;

	list_del(&res->sibling);
	free((char *)res->name);
	free(res);

	return 0;
}

/* The root resource for the whole io space */
struct resource iomem_resource = {
	.start = 0,
	.size = ~0,
};

/*
 * request a region inside the io space
 */
struct resource *request_iomem_region(const char *name,
		resource_size_t start, resource_size_t size)
{
	return request_region(&iomem_resource, name, start, size);
}

static int iomem_init(void)
{
	init_resource(&iomem_resource, "iomem");

	return 0;
}
postcore_initcall(iomem_init);