mmu.c

来自「PXA250上的XBOOT」· C语言 代码 · 共 55 行

/* 
 * $Id: mmu.c,v 1.1 2002/12/05 22:20:38 telka Exp $
 *
 * Copyright (C) 2001, 2002 ETC s.r.o.
 *
 * 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 2
 * 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 *
 * Written by Marcel Telka <[e-mail]>, 2001, 2002.
 *
 * These functions are used from start.s without MMU enabled.
 * They cannot use global variables or virtual addresses.
 *
 */

#include <stdint.h>

#include "atable.h"

void
CreatePageTables( uint32_t *FLD, struct AddressTable *MemoryMap )
{
	/* FLD = Address of first level descriptors (size = 4096) */
	uint32_t i;

	/* clearing all first level descriptors */
	for (i = 0; i < 4096; i++)
		FLD[i] = 0;

	/* mapping from MemoryMap */
	for (; MemoryMap->Size; MemoryMap++) {
		uint32_t VA = (MemoryMap->VirtAddress & 0x1FF00000) >> 20;
		uint32_t PA = MemoryMap->PhysAddress & 0xFFF00000;

		for (i = 0; i < MemoryMap->Size; i++) {
			FLD[VA | 0x800] = PA | 0x40E;
			FLD[VA | 0xA00] = PA | 0x402;
			VA++;
			PA += 0x100000;
		}
	}
}