/*
 * Copyright (c) 2010-2014 Richard Braun.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * 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, see <http://www.gnu.org/licenses/>.
 */

#ifndef _X86_BIOSMEM_H
#define _X86_BIOSMEM_H

#include <sys/types.h>
#include "x15/multiboot.h"

/*
 * Address where the address of the Extended BIOS Data Area segment can be
 * found.
 */
#define BIOSMEM_EBDA_PTR 0x40e

/*
 * Significant low memory addresses.
 *
 * The first 64 KiB are reserved for various reasons (e.g. to preserve BIOS
 * data and to work around data corruption on some hardware).
 */
#define BIOSMEM_BASE        0x010000
#define BIOSMEM_BASE_END    0x0a0000
#define BIOSMEM_EXT_ROM     0x0e0000
#define BIOSMEM_ROM         0x0f0000
#define BIOSMEM_END         0x100000

/*
 * Early initialization of the biosmem module.
 *
 * This function processes the given multiboot data for BIOS-provided
 * memory information, and sets up a bootstrap physical page allocator.
 *
 * It is called before paging is enabled.
 */
void biosmem_bootstrap(struct multiboot_raw_info *mbi);

/*
 * Allocate contiguous physical pages during bootstrap.
 *
 * This function is called before paging is enabled. It should only be used
 * to allocate initial page table pages. Those pages are later loaded into
 * the VM system (as reserved pages) which means they can be freed like other
 * regular pages. Users should fix up the type of those pages once the VM
 * system is initialized.
 */
void * biosmem_bootalloc(unsigned int nr_pages);

/*
 * Return the amount of physical memory that can be directly mapped.
 *
 * This includes the size of both the DMA/DMA32 and DIRECTMAP segments.
 */
phys_addr_t biosmem_directmap_size(void);

/*
 * Set up physical memory based on the information obtained during bootstrap
 * and load it in the VM system.
 */
void biosmem_setup(void);

/*
 * Free all usable memory.
 *
 * This includes ranges that weren't part of the bootstrap allocator initial
 * heap, e.g. because they contained boot data.
 */
void biosmem_free_usable(void);

#endif /* _X86_BIOSMEM_H */