nand_boot.c

/*
 * (C) Copyright 2006-2008
 * Stefan Roese, DENX Software Engineering, sr@denx.de.
 *
 * 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
 */

#include <common.h>
#include <nand.h>
#include <asm/io.h>

#define CFG_NAND_READ_DELAY \
	{ volatile int dummy; int i; for (i=0; i<10000; i++) dummy = i; }

static int nand_ecc_pos[] = CFG_NAND_ECCPOS;

extern void board_nand_init(struct nand_chip *nand);

#if (CFG_NAND_PAGE_SIZE <= 512)
/*
 * NAND command for small page NAND devices (512)
 */
static int nand_command(struct mtd_info *mtd, int block, int page, int offs, u8 cmd)
{
	struct nand_chip *this = mtd->priv;
	int page_addr = page + block * CFG_NAND_PAGE_COUNT;

	if (this->dev_ready)
		while (!this->dev_ready(mtd))
			;
	else
		CFG_NAND_READ_DELAY;

	/* Begin command latch cycle */
	this->cmd_ctrl(mtd, cmd, NAND_CTRL_CLE | NAND_CTRL_CHANGE);
	/* Set ALE and clear CLE to start address cycle */
	/* Column address */
	this->cmd_ctrl(mtd, offs, NAND_CTRL_ALE | NAND_CTRL_CHANGE);
	this->cmd_ctrl(mtd, page_addr & 0xff, 0); /* A[16:9] */
	this->cmd_ctrl(mtd, (page_addr >> 8) & 0xff, 0); /* A[24:17] */
#ifdef CFG_NAND_4_ADDR_CYCLE
	/* One more address cycle for devices > 32MiB */
	this->cmd_ctrl(mtd, (page_addr >> 16) & 0x0f, 0); /* A[28:25] */
#endif
	/* Latch in address */
	this->cmd_ctrl(mtd, NAND_CMD_NONE, NAND_NCE | NAND_CTRL_CHANGE);

	/*
	 * Wait a while for the data to be ready
	 */
	if (this->dev_ready)
		while (!this->dev_ready(mtd))
			;
	else
		CFG_NAND_READ_DELAY;

	return 0;