unsigned long nandptr = nand->IO_ADDR;

#ifdef PSYCHO_DEBUG
	printf("nand_write_oob(%lx, %d): %2.2X %2.2X %2.2X %2.2X ... %2.2X %2.2X .. %2.2X %2.2X\n",
	       (long)ofs, len, buf[0], buf[1], buf[2], buf[3],
	       buf[8], buf[9], buf[14],buf[15]);
#endif

	NAND_ENABLE_CE(nand);  /* set pin low to enable chip */

	/* Reset the chip */
	NanD_Command(nand, NAND_CMD_RESET);

	/* issue the Read2 command to set the pointer to the Spare Data Area. */
	NanD_Command(nand, NAND_CMD_READOOB);
	NanD_Address(nand, ADDR_COLUMN_PAGE, ofs);

	/* update address for 2M x 8bit devices. OOB starts on the second */
	/* page to maintain compatibility with nand_read_ecc. */
	if (nand->page256) {
		if (!(ofs & 0x8))
			ofs += 0x100;
		else
			ofs -= 0x8;
	}

	/* issue the Serial Data In command to initial the Page Program process */
	NanD_Command(nand, NAND_CMD_SEQIN);
	NanD_Address(nand, ADDR_COLUMN_PAGE, ofs);

	/* treat crossing 8-byte OOB data for 2M x 8bit devices */
	/* Note: datasheet says it should automaticaly wrap to the */
	/*       next OOB block, but it didn't work here. mf.      */
	if (nand->page256 && ofs + len > (ofs | 0x7) + 1) {
		len256 = (ofs | 0x7) + 1 - ofs;
		for (i = 0; i < len256; i++)
			WRITE_NAND(buf[i], nandptr);

		NanD_Command(nand, NAND_CMD_PAGEPROG);
		NanD_Command(nand, NAND_CMD_STATUS);
#ifdef NAND_NO_RB
   		{ u_char ret_val;
    		  do{
		  	ret_val = READ_NAND(nandptr); /* wait till ready */
    		  }while((ret_val & 0x40) != 0x40);
		}
#endif
		if (READ_NAND(nandptr) & 1) {
			puts ("Error programming oob data\n");
			/* There was an error */
			NAND_DISABLE_CE(nand);  /* set pin high */
			*retlen = 0;
			return -1;
		}
		NanD_Command(nand, NAND_CMD_SEQIN);
		NanD_Address(nand, ADDR_COLUMN_PAGE, ofs & (~0x1ff));
	}

	for (i = len256; i < len; i++)
		WRITE_NAND(buf[i], nandptr);

	NanD_Command(nand, NAND_CMD_PAGEPROG);
	NanD_Command(nand, NAND_CMD_STATUS);
#ifdef NAND_NO_RB
	{ u_char ret_val;
	  do{
		ret_val = READ_NAND(nandptr); /* wait till ready */
	  } while((ret_val & 0x40) != 0x40);
	}
#endif
	if (READ_NAND(nandptr) & 1) {
		puts ("Error programming oob data\n");
		/* There was an error */
		NAND_DISABLE_CE(nand);  /* set pin high */
		*retlen = 0;
		return -1;
	}

	NAND_DISABLE_CE(nand);  /* set pin high */
	*retlen = len;
	return 0;

}

int nand_erase(struct nand_chip* nand, size_t ofs, size_t len, int clean)
{
	/* This is defined as a structure so it will work on any system
	 * using native endian jffs2 (the default).
	 */
	static struct jffs2_unknown_node clean_marker = {
		JFFS2_MAGIC_BITMASK,
		JFFS2_NODETYPE_CLEANMARKER,
		8		/* 8 bytes in this node */
	};
	unsigned long nandptr;
	struct Nand *mychip;
	int ret = 0;

	if (ofs & (nand->erasesize-1) || len & (nand->erasesize-1)) {
		printf ("Offset and size must be sector aligned, erasesize = %d\n",
			(int) nand->erasesize);
		return -1;
	}

	nandptr = nand->IO_ADDR;

	/* Select the NAND device */
    NAND_ENABLE_CE(nand);  /* set pin low */

	/* Check the WP bit */
	NanD_Command(nand, NAND_CMD_STATUS);
	if (!(READ_NAND(nand->IO_ADDR) & 0x80)) {
		printf ("nand_write_ecc: Device is write protected!!!\n");
		ret = -1;
		goto out;
	}

	/* Check the WP bit */
	NanD_Command(nand, NAND_CMD_STATUS);
	if (!(READ_NAND(nand->IO_ADDR) & 0x80)) {
//		printf ("%s: Device is write protected!!!\n", __FUNCTION__);
		ret = -1;
		goto out;
	}

	/* FIXME: Do nand in the background. Use timers or schedule_task() */
	while(len) {
		/*mychip = &nand->chips[shr(ofs, nand->chipshift)];*/
		mychip = &nand->chips[ofs >> nand->chipshift];

		/* always check for bad block first, genuine bad blocks
		 * should _never_  be erased.
		 */
		if (ALLOW_ERASE_BAD_DEBUG || !check_block(nand, ofs)) {
			/* Select the NAND device */
			NAND_ENABLE_CE(nand);  /* set pin low */

			NanD_Command(nand, NAND_CMD_ERASE1);
			NanD_Address(nand, ADDR_PAGE, ofs);
			NanD_Command(nand, NAND_CMD_ERASE2);

			NanD_Command(nand, NAND_CMD_STATUS);

#ifdef NAND_NO_RB
			{ u_char ret_val;
			  do{
				ret_val = READ_NAND(nandptr); /* wait till ready */
			  } while((ret_val & 0x40) != 0x40);
			}
#endif
			if (READ_NAND(nandptr) & 1) {
//				printf ("%s: Error erasing at 0x%lx\n",
//					__FUNCTION__, (long)ofs);
				/* There was an error */
				ret = -1;
				goto out;
			}
			if (clean) {
				int n;	/* return value not used */
				int p, l;

				/* clean marker position and size depend
				 * on the page size, since 256 byte pages
				 * only have 8 bytes of oob data
				 */
				if (nand->page256) {
					p = NAND_JFFS2_OOB8_FSDAPOS;
					l = NAND_JFFS2_OOB8_FSDALEN;
				}
				else {
					p = NAND_JFFS2_OOB16_FSDAPOS;
					l = NAND_JFFS2_OOB16_FSDALEN;
				}

				ret = nand_write_oob(nand, ofs + p, l, (size_t *)&n,
						     (u_char *)&clean_marker);
				/* quit here if write failed */
				if (ret)
					goto out;
			}
		}
		ofs += nand->erasesize;
		len -= nand->erasesize;
	}

out:
	/* De-select the NAND device */
	NAND_DISABLE_CE(nand);  /* set pin high */
	return ret;
}

static __inline int nandcheck(unsigned long potential, unsigned long physadr)
{
	return 0;
}

unsigned long nand_probe(unsigned long physadr)
{
	struct nand_chip *nand = NULL;
	int i = 0, ChipID = 1;

#ifdef CONFIG_MTD_NAND_ECC_JFFS2
	oob_config.ecc_pos[0] = NAND_JFFS2_OOB_ECCPOS0;
	oob_config.ecc_pos[1] = NAND_JFFS2_OOB_ECCPOS1;
	oob_config.ecc_pos[2] = NAND_JFFS2_OOB_ECCPOS2;
	oob_config.ecc_pos[3] = NAND_JFFS2_OOB_ECCPOS3;
	oob_config.ecc_pos[4] = NAND_JFFS2_OOB_ECCPOS4;
	oob_config.ecc_pos[5] = NAND_JFFS2_OOB_ECCPOS5;
	oob_config.eccvalid_pos = 4;
#else
	oob_config.ecc_pos[0] = NAND_NOOB_ECCPOS0;
	oob_config.ecc_pos[1] = NAND_NOOB_ECCPOS1;
	oob_config.ecc_pos[2] = NAND_NOOB_ECCPOS2;
	oob_config.ecc_pos[3] = NAND_NOOB_ECCPOS3;
	oob_config.ecc_pos[4] = NAND_NOOB_ECCPOS4;
	oob_config.ecc_pos[5] = NAND_NOOB_ECCPOS5;
	oob_config.eccvalid_pos = NAND_NOOB_ECCVPOS;
#endif
	oob_config.badblock_pos = 5;

	for (i=0; i<CFG_MAX_NAND_DEVICE; i++) {
		if (nand_dev_desc[i].ChipID == NAND_ChipID_UNKNOWN) {
			nand = &nand_dev_desc[i];
			break;
		}
	}
	if (!nand)
		return (0);

	memset((char *)nand, 0, sizeof(struct nand_chip));

	nand->IO_ADDR = physadr;
	nand->cache_page = -1;  /* init the cache page */
	NanD_ScanChips(nand);

	if (nand->totlen == 0) {
		/* no chips found, clean up and quit */
		memset((char *)nand, 0, sizeof(struct nand_chip));
		nand->ChipID = NAND_ChipID_UNKNOWN;
		return (0);
	}

	nand->ChipID = ChipID;
	if (curr_device == -1)
		curr_device = i;

	nand->data_buf = malloc (nand->oobblock + nand->oobsize);
	if (!nand->data_buf) {
		puts ("Cannot allocate memory for data structures.\n");
		return (0);
	}

	return (nand->totlen);
}

#ifdef CONFIG_MTD_NAND_ECC
/*
 * Pre-calculated 256-way 1 byte column parity
 */
static const u_char nand_ecc_precalc_table[] = {
	0x00, 0x55, 0x56, 0x03, 0x59, 0x0c, 0x0f, 0x5a, 0x5a, 0x0f, 0x0c, 0x59, 0x03, 0x56, 0x55, 0x00,
	0x65, 0x30, 0x33, 0x66, 0x3c, 0x69, 0x6a, 0x3f, 0x3f, 0x6a, 0x69, 0x3c, 0x66, 0x33, 0x30, 0x65,
	0x66, 0x33, 0x30, 0x65, 0x3f, 0x6a, 0x69, 0x3c, 0x3c, 0x69, 0x6a, 0x3f, 0x65, 0x30, 0x33, 0x66,
	0x03, 0x56, 0x55, 0x00, 0x5a, 0x0f, 0x0c, 0x59, 0x59, 0x0c, 0x0f, 0x5a, 0x00, 0x55, 0x56, 0x03,
	0x69, 0x3c, 0x3f, 0x6a, 0x30, 0x65, 0x66, 0x33, 0x33, 0x66, 0x65, 0x30, 0x6a, 0x3f, 0x3c, 0x69,
	0x0c, 0x59, 0x5a, 0x0f, 0x55, 0x00, 0x03, 0x56, 0x56, 0x03, 0x00, 0x55, 0x0f, 0x5a, 0x59, 0x0c,
	0x0f, 0x5a, 0x59, 0x0c, 0x56, 0x03, 0x00, 0x55, 0x55, 0x00, 0x03, 0x56, 0x0c, 0x59, 0x5a, 0x0f,
	0x6a, 0x3f, 0x3c, 0x69, 0x33, 0x66, 0x65, 0x30, 0x30, 0x65, 0x66, 0x33, 0x69, 0x3c, 0x3f, 0x6a,
	0x6a, 0x3f, 0x3c, 0x69, 0x33, 0x66, 0x65, 0x30, 0x30, 0x65, 0x66, 0x33, 0x69, 0x3c, 0x3f, 0x6a,
	0x0f, 0x5a, 0x59, 0x0c, 0x56, 0x03, 0x00, 0x55, 0x55, 0x00, 0x03, 0x56, 0x0c, 0x59, 0x5a, 0x0f,
	0x0c, 0x59, 0x5a, 0x0f, 0x55, 0x00, 0x03, 0x56, 0x56, 0x03, 0x00, 0x55, 0x0f, 0x5a, 0x59, 0x0c,
	0x69, 0x3c, 0x3f, 0x6a, 0x30, 0x65, 0x66, 0x33, 0x33, 0x66, 0x65, 0x30, 0x6a, 0x3f, 0x3c, 0x69,
	0x03, 0x56, 0x55, 0x00, 0x5a, 0x0f, 0x0c, 0x59, 0x59, 0x0c, 0x0f, 0x5a, 0x00, 0x55, 0x56, 0x03,
	0x66, 0x33, 0x30, 0x65, 0x3f, 0x6a, 0x69, 0x3c, 0x3c, 0x69, 0x6a, 0x3f, 0x65, 0x30, 0x33, 0x66,
	0x65, 0x30, 0x33, 0x66, 0x3c, 0x69, 0x6a, 0x3f, 0x3f, 0x6a, 0x69, 0x3c, 0x66, 0x33, 0x30, 0x65,
	0x00, 0x55, 0x56, 0x03, 0x59, 0x0c, 0x0f, 0x5a, 0x5a, 0x0f, 0x0c, 0x59, 0x03, 0x56, 0x55, 0x00
};


/*
 * Creates non-inverted ECC code from line parity
 */
static void nand_trans_result(u_char reg2, u_char reg3,
	u_char *ecc_code)
{
	u_char a, b, i, tmp1, tmp2;

	/* Initialize variables */
	a = b = 0x80;
	tmp1 = tmp2 = 0;

	/* Calculate first ECC byte */
	for (i = 0; i < 4; i++) {
		if (reg3 & a)		/* LP15,13,11,9 --> ecc_code[0] */
			tmp1 |= b;
		b >>= 1;
		if (reg2 & a)		/* LP14,12,10,8 --> ecc_code[0] */
			tmp1 |= b;
		b >>= 1;
		a >>= 1;
	}

	/* Calculate second ECC byte */
	b = 0x80;
	for (i = 0; i < 4; i++) {
		if (reg3 & a)		/* LP7,5,3,1 --> ecc_code[1] */
			tmp2 |= b;
		b >>= 1;
		if (reg2 & a)		/* LP6,4,2,0 --> ecc_code[1] */
			tmp2 |= b;
		b >>= 1;
		a >>= 1;
	}

	/* Store two of the ECC bytes */
	ecc_code[0] = tmp1;
	ecc_code[1] = tmp2;
}

/*
 * Calculate 3 byte ECC code for 256 byte block
 */
static void nand_calculate_ecc (const u_char *dat, u_char *ecc_code)
{
	u_char idx, reg1, reg3;
	int j;

	/* Initialize variables */
	reg1 = reg3 = 0;
	ecc_code[0] = ecc_code[1] = ecc_code[2] = 0;

	/* Build up column parity */
	for(j = 0; j < 256; j++) {

		/* Get CP0 - CP5 from table */
		idx = nand_ecc_precalc_table[dat[j]];
		reg1 ^= idx;

		/* All bit XOR = 1 ? */
		if (idx & 0x40) {
			reg3 ^= (u_char) j;
		}
	}

	/* Create non-inverted ECC code from line parity */
	nand_trans_result((reg1 & 0x40) ? ~reg3 : reg3, reg3, ecc_code);

	/* Calculate final ECC code */
	ecc_code[0] = ~ecc_code[0];
	ecc_code[1] = ~ecc_code[1];
	ecc_code[2] = ((~reg1) << 2) | 0x03;
}

/*
 * Detect and correct a 1 bit error for 256 byte block
 */
static int nand_correct_data (u_char *dat, u_char *read_ecc, u_char *calc_ecc)
{
	u_char a, b, c, d1, d2, d3, add, bit, i;

	/* Do error detection */
	d1 = calc_ecc[0] ^ read_ecc[0];
	d2 = calc_ecc[1] ^ read_ecc[1];
	d3 = calc_ecc[2] ^ read_ecc[2];

	if ((d1 | d2 | d3) == 0) {
		/* No errors */
		return 0;
	}
	else {
		a = (d1 ^ (d1 >> 1)) & 0x55;
		b = (d2 ^ (d2 >> 1)) & 0x55;
		c = (d3 ^ (d3 >> 1)) & 0x54;

		/* Found and will correct single bit error in the data */
		if ((a == 0x55) && (b == 0x55) && (c == 0x54)) {
			c = 0x80;
			add = 0;
			a = 0x80;
			for (i=0; i<4; i++) {
				if (d1 & c)
					add |= a;
				c >>= 2;
				a >>= 1;
			}
			c = 0x80;
			for (i=0; i<4; i++) {
				if (d2 & c)
					add |= a;
				c >>= 2;
				a >>= 1;
			}
			bit = 0;
			b = 0x04;
			c = 0x80;
			for (i=0; i<3; i++) {
				if (d3 & c)
					bit |= b;
				c >>= 2;
				b >>= 1;
			}
			b = 0x01;
			a = dat[add];
			a ^= (b << bit);
			dat[add] = a;
			return 1;
		}
		else {
			i = 0;
			while (d1) {
				if (d1 & 0x01)
					++i;
				d1 >>= 1;
			}
			while (d2) {
				if (d2 & 0x01)
					++i;
				d2 >>= 1;
			}
			while (d3) {
				if (d3 & 0x01)
					++i;
				d3 >>= 1;
			}
			if (i == 1) {
				/* ECC Code Error Correction */
				read_ecc[0] = calc_ecc[0];
				read_ecc[1] = calc_ecc[1];
				read_ecc[2] = calc_ecc[2];
				return 2;
			}
			else {
				/* Uncorrectable Error */
				return -1;
			}
		}
	}

	/* Should never happen */
	return -1;
}
#endif

#ifdef CONFIG_JFFS2_NAND

int read_jffs2_nand(size_t start, size_t len,
		    size_t * retlen, u_char * buf, int nanddev)
{
	return nand_rw(nand_dev_desc + nanddev, NANDRW_READ | NANDRW_JFFS2,
		       start, len, retlen, buf);
}

#endif /* CONFIG_JFFS2_NAND */