/*
 * (C) Copyright 2006 DENX Software Engineering
 *
 * Implementation for U-Boot 1.1.6 by Samsung
 *
 * (C) Copyright 2008
 * Guennadi Liakhovetki, DENX Software Engineering, <lg@denx.de>
 *
 * 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 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 <linux/mtd/nand.h>

#include <asm/arch/s3c6400.h>

#include <asm/io.h>
#include <asm/errno.h>

#define MAX_CHIPS	2
static int nand_cs[MAX_CHIPS] = {0, 1};

#ifdef CONFIG_NAND_SPL
#define printf(arg...) do {} while (0)
#endif

/* Nand flash definition values by jsgood */
#ifdef S3C_NAND_DEBUG
/*
 * Function to print out oob buffer for debugging
 * Written by jsgood
 */
static void print_oob(const char *header, struct mtd_info *mtd)
{
	int i;
	struct nand_chip *chip = mtd->priv;

	printf("%s:\t", header);

	for (i = 0; i < 64; i++)
		printf("%02x ", chip->oob_poi[i]);

	printf("\n");
}
#endif /* S3C_NAND_DEBUG */

static void s3c_nand_select_chip(struct mtd_info *mtd, int chip)
{
	int ctrl = readl(NFCONT);

	switch (chip) {
	case -1:
		ctrl |= 6;
		break;
	case 0:
		ctrl &= ~2;
		break;
	case 1:
		ctrl &= ~4;
		break;
	default:
		return;
	}

	writel(ctrl, NFCONT);
}

/*
 * Hardware specific access to control-lines function
 * Written by jsgood
 */
static void s3c_nand_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int ctrl)
{
	struct nand_chip *this = mtd->priv;

	if (ctrl & NAND_CTRL_CHANGE) {
		if (ctrl & NAND_CLE)
			this->IO_ADDR_W = (void __iomem *)NFCMMD;
		else if (ctrl & NAND_ALE)
			this->IO_ADDR_W = (void __iomem *)NFADDR;
		else
			this->IO_ADDR_W = (void __iomem *)NFDATA;
		if (ctrl & NAND_NCE)
			s3c_nand_select_chip(mtd, *(int *)this->priv);
		else
			s3c_nand_select_chip(mtd, -1);
	}

	if (cmd != NAND_CMD_NONE)
		writeb(cmd, this->IO_ADDR_W);
}

/*
 * Function for checking device ready pin
 * Written by jsgood
 */
static int s3c_nand_device_ready(struct mtd_info *mtdinfo)
{
	return !!(readl(NFSTAT) & NFSTAT_RnB);
}

#ifdef CONFIG_SYS_S3C_NAND_HWECC
/*
 * This function is called before encoding ecc codes to ready ecc engine.
 * Written by jsgood
 */
static void s3c_nand_enable_hwecc(struct mtd_info *mtd, int mode)
{
	u_long nfcont, nfconf;

	/*
	 * The original driver used 4-bit ECC for "new" MLC chips, i.e., for
	 * those with non-zero ID[3][3:2], which anyway only holds for ST
	 * (Numonyx) chips
	 */
	nfconf = readl(NFCONF) & ~NFCONF_ECC_4BIT;

	writel(nfconf, NFCONF);

	/* Initialize & unlock */
	nfcont = readl(NFCONT);
	nfcont |= NFCONT_INITECC;
	nfcont &= ~NFCONT_MECCLOCK;

	if (mode == NAND_ECC_WRITE)
		nfcont |= NFCONT_ECC_ENC;
	else if (mode == NAND_ECC_READ)
		nfcont &= ~NFCONT_ECC_ENC;

	writel(nfcont, NFCONT);
}

/*
 * This function is called immediately after encoding ecc codes.
 * This function returns encoded ecc codes.
 * Written by jsgood
 */
static int s3c_nand_calculate_ecc(struct mtd_info *mtd, const u_char *dat,
				  u_char *ecc_code)
{
	u_long nfcont, nfmecc0;

	/* Lock */
	nfcont = readl(NFCONT);
	nfcont |= NFCONT_MECCLOCK;
	writel(nfcont, NFCONT);

	nfmecc0 = readl(NFMECC0);

	ecc_code[0] = nfmecc0 & 0xff;
	ecc_code[1] = (nfmecc0 >> 8) & 0xff;
	ecc_code[2] = (nfmecc0 >> 16) & 0xff;
	ecc_code[3] = (nfmecc0 >> 24) & 0xff;

	return 0;
}

/*
 * This function determines whether read data is good or not.
 * If SLC, must write ecc codes to controller before reading status bit.
 * If MLC, status bit is already set, so only reading is needed.
 * If status bit is good, return 0.
 * If correctable errors occured, do that.
 * If uncorrectable errors occured, return -1.
 * Written by jsgood
 */
static int s3c_nand_correct_data(struct mtd_info *mtd, u_char *dat,
				 u_char *read_ecc, u_char *calc_ecc)
{
	int ret = -1;
	u_long nfestat0, nfmeccdata0, nfmeccdata1, err_byte_addr;
	u_char err_type, repaired;

	/* SLC: Write ecc to compare */
	nfmeccdata0 = (calc_ecc[1] << 16) | calc_ecc[0];
	nfmeccdata1 = (calc_ecc[3] << 16) | calc_ecc[2];
	writel(nfmeccdata0, NFMECCDATA0);
	writel(nfmeccdata1, NFMECCDATA1);

	/* Read ecc status */
	nfestat0 = readl(NFESTAT0);
	err_type = nfestat0 & 0x3;

	switch (err_type) {
	case 0: /* No error */
		ret = 0;
		break;

	case 1:
		/*
		 * 1 bit error (Correctable)
		 * (nfestat0 >> 7) & 0x7ff	:error byte number
		 * (nfestat0 >> 4) & 0x7	:error bit number
		 */
		err_byte_addr = (nfestat0 >> 7) & 0x7ff;
		repaired = dat[err_byte_addr] ^ (1 << ((nfestat0 >> 4) & 0x7));

		printf("S3C NAND: 1 bit error detected at byte %ld. "
		       "Correcting from 0x%02x to 0x%02x...OK\n",
		       err_byte_addr, dat[err_byte_addr], repaired);

		dat[err_byte_addr] = repaired;

		ret = 1;
		break;

	case 2: /* Multiple error */
	case 3: /* ECC area error */
		printf("S3C NAND: ECC uncorrectable error detected. "
		       "Not correctable.\n");
		ret = -1;
		break;
	}

	return ret;
}
#endif /* CONFIG_SYS_S3C_NAND_HWECC */

/*
 * Board-specific NAND initialization. The following members of the
 * argument are board-specific (per include/linux/mtd/nand.h):
 * - IO_ADDR_R?: address to read the 8 I/O lines of the flash device
 * - IO_ADDR_W?: address to write the 8 I/O lines of the flash device
 * - hwcontrol: hardwarespecific function for accesing control-lines
 * - dev_ready: hardwarespecific function for  accesing device ready/busy line
 * - enable_hwecc?: function to enable (reset)  hardware ecc generator. Must
 *   only be provided if a hardware ECC is available
 * - eccmode: mode of ecc, see defines
 * - chip_delay: chip dependent delay for transfering data from array to
 *   read regs (tR)
 * - options: various chip options. They can partly be set to inform
 *   nand_scan about special functionality. See the defines for further
 *   explanation
 * Members with a "?" were not set in the merged testing-NAND branch,
 * so they are not set here either.
 */
int board_nand_init(struct nand_chip *nand)
{
	static int chip_n;

	if (chip_n >= MAX_CHIPS)
		return -ENODEV;

	NFCONT_REG = (NFCONT_REG & ~NFCONT_WP) | NFCONT_ENABLE | 0x6;

	nand->IO_ADDR_R		= (void __iomem *)NFDATA;
	nand->IO_ADDR_W		= (void __iomem *)NFDATA;
	nand->cmd_ctrl		= s3c_nand_hwcontrol;
	nand->dev_ready		= s3c_nand_device_ready;
	nand->select_chip	= s3c_nand_select_chip;
	nand->options		= 0;
#ifdef CONFIG_NAND_SPL
	nand->read_byte		= nand_read_byte;
	nand->write_buf		= nand_write_buf;
	nand->read_buf		= nand_read_buf;
#endif

#ifdef CONFIG_SYS_S3C_NAND_HWECC
	nand->ecc.hwctl		= s3c_nand_enable_hwecc;
	nand->ecc.calculate	= s3c_nand_calculate_ecc;
	nand->ecc.correct	= s3c_nand_correct_data;

	/*
	 * If you get more than 1 NAND-chip with different page-sizes on the
	 * board one day, it will get more complicated...
	 */
	nand->ecc.mode		= NAND_ECC_HW;
	nand->ecc.size		= CONFIG_SYS_NAND_ECCSIZE;
	nand->ecc.bytes		= CONFIG_SYS_NAND_ECCBYTES;
#else
	nand->ecc.mode		= NAND_ECC_SOFT;
#endif /* ! CONFIG_SYS_S3C_NAND_HWECC */

	nand->priv		= nand_cs + chip_n++;

	return 0;
}