drivers/mtd/nand/davinci_nand.c - platform/external/u-boot - Gitiles

 /*
  * NAND driver for TI DaVinci based boards.
  *
  * Copyright (C) 2007 Sergey Kubushyn <ksi@koi8.net>
  *
  * Based on Linux DaVinci NAND driver by TI. Original copyright follows:
  */

 /*
  *
  * linux/drivers/mtd/nand/nand_davinci.c
  *
  * NAND Flash Driver
  *
  * Copyright (C) 2006 Texas Instruments.
  *
  * ----------------------------------------------------------------------------
  *
  * SPDX-License-Identifier:	GPL-2.0+
  *
  * ----------------------------------------------------------------------------
  *
  *  Overview:
  *   This is a device driver for the NAND flash device found on the
  *   DaVinci board which utilizes the Samsung k9k2g08 part.
  *
  Modifications:
  ver. 1.0: Feb 2005, Vinod/Sudhakar
  -
  */

 #include <common.h>
 #include <asm/io.h>
 #include <nand.h>
 #include <asm/ti-common/davinci_nand.h>

 /* Definitions for 4-bit hardware ECC */
 #define NAND_TIMEOUT			10240
 #define NAND_ECC_BUSY			0xC
 #define NAND_4BITECC_MASK		0x03FF03FF
 #define EMIF_NANDFSR_ECC_STATE_MASK  	0x00000F00
 #define ECC_STATE_NO_ERR		0x0
 #define ECC_STATE_TOO_MANY_ERRS		0x1
 #define ECC_STATE_ERR_CORR_COMP_P	0x2
 #define ECC_STATE_ERR_CORR_COMP_N	0x3

 /*
  * Exploit the little endianness of the ARM to do multi-byte transfers
  * per device read. This can perform over twice as quickly as individual
  * byte transfers when buffer alignment is conducive.
  *
  * NOTE: This only works if the NAND is not connected to the 2 LSBs of
  * the address bus. On Davinci EVM platforms this has always been true.
  */
 static void nand_davinci_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
 {
 	struct nand_chip *chip = mtd->priv;
 	const u32 *nand = chip->IO_ADDR_R;

 	/* Make sure that buf is 32 bit aligned */
 	if (((int)buf & 0x3) != 0) {
 		if (((int)buf & 0x1) != 0) {
 			if (len) {
 				*buf = readb(nand);
 				buf += 1;
 				len--;
 			}
 		}

 		if (((int)buf & 0x3) != 0) {
 			if (len >= 2) {
 				*(u16 *)buf = readw(nand);
 				buf += 2;
 				len -= 2;
 			}
 		}
 	}

 	/* copy aligned data */
 	while (len >= 4) {
 		*(u32 *)buf = __raw_readl(nand);
 		buf += 4;
 		len -= 4;
 	}

 	/* mop up any remaining bytes */
 	if (len) {
 		if (len >= 2) {
 			*(u16 *)buf = readw(nand);
 			buf += 2;
 			len -= 2;
 		}

 		if (len)
 			*buf = readb(nand);
 	}
 }

 static void nand_davinci_write_buf(struct mtd_info *mtd, const uint8_t *buf,
 				   int len)
 {
 	struct nand_chip *chip = mtd->priv;
 	const u32 *nand = chip->IO_ADDR_W;

 	/* Make sure that buf is 32 bit aligned */
 	if (((int)buf & 0x3) != 0) {
 		if (((int)buf & 0x1) != 0) {
 			if (len) {
 				writeb(*buf, nand);
 				buf += 1;
 				len--;
 			}
 		}

 		if (((int)buf & 0x3) != 0) {
 			if (len >= 2) {
 				writew(*(u16 *)buf, nand);
 				buf += 2;
 				len -= 2;
 			}
 		}
 	}

 	/* copy aligned data */
 	while (len >= 4) {
 		__raw_writel(*(u32 *)buf, nand);
 		buf += 4;
 		len -= 4;
 	}

 	/* mop up any remaining bytes */
 	if (len) {
 		if (len >= 2) {
 			writew(*(u16 *)buf, nand);
 			buf += 2;
 			len -= 2;
 		}

 		if (len)
 			writeb(*buf, nand);
 	}
 }

 static void nand_davinci_hwcontrol(struct mtd_info *mtd, int cmd,
 		unsigned int ctrl)
 {
 	struct		nand_chip *this = mtd->priv;
 	u_int32_t	IO_ADDR_W = (u_int32_t)this->IO_ADDR_W;

 	if (ctrl & NAND_CTRL_CHANGE) {
 		IO_ADDR_W &= ~(MASK_ALE|MASK_CLE);

 		if (ctrl & NAND_CLE)
 			IO_ADDR_W |= MASK_CLE;
 		if (ctrl & NAND_ALE)
 			IO_ADDR_W |= MASK_ALE;
 		this->IO_ADDR_W = (void __iomem *) IO_ADDR_W;
 	}

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

 #ifdef CONFIG_SYS_NAND_HW_ECC

 static u_int32_t nand_davinci_readecc(struct mtd_info *mtd)
 {
 	u_int32_t	ecc = 0;

 	ecc = __raw_readl(&(davinci_emif_regs->nandfecc[
 				CONFIG_SYS_NAND_CS - 2]));

 	return ecc;
 }

 static void nand_davinci_enable_hwecc(struct mtd_info *mtd, int mode)
 {
 	u_int32_t	val;

 	/* reading the ECC result register resets the ECC calculation */
 	nand_davinci_readecc(mtd);

 	val = __raw_readl(&davinci_emif_regs->nandfcr);
 	val |= DAVINCI_NANDFCR_NAND_ENABLE(CONFIG_SYS_NAND_CS);
 	val |= DAVINCI_NANDFCR_1BIT_ECC_START(CONFIG_SYS_NAND_CS);
 	__raw_writel(val, &davinci_emif_regs->nandfcr);
 }

 static int nand_davinci_calculate_ecc(struct mtd_info *mtd, const u_char *dat,
 		u_char *ecc_code)
 {
 	u_int32_t		tmp;

 	tmp = nand_davinci_readecc(mtd);

 	/* Squeeze 4 bytes ECC into 3 bytes by removing RESERVED bits
 	 * and shifting. RESERVED bits are 31 to 28 and 15 to 12. */
 	tmp = (tmp & 0x00000fff) | ((tmp & 0x0fff0000) >> 4);

 	/* Invert so that erased block ECC is correct */
 	tmp = ~tmp;

 	*ecc_code++ = tmp;
 	*ecc_code++ = tmp >>  8;
 	*ecc_code++ = tmp >> 16;

 	/* NOTE:  the above code matches mainline Linux:
 	 *	.PQR.stu ==> ~PQRstu
 	 *
 	 * MontaVista/TI kernels encode those bytes differently, use
 	 * complicated (and allegedly sometimes-wrong) correction code,
 	 * and usually shipped with U-Boot that uses software ECC:
 	 *	.PQR.stu ==> PsQRtu
 	 *
 	 * If you need MV/TI compatible NAND I/O in U-Boot, it should
 	 * be possible to (a) change the mangling above, (b) reverse
 	 * that mangling in nand_davinci_correct_data() below.
 	 */

 	return 0;
 }

 static int nand_davinci_correct_data(struct mtd_info *mtd, u_char *dat,
 		u_char *read_ecc, u_char *calc_ecc)
 {
 	struct nand_chip *this = mtd->priv;
 	u_int32_t ecc_nand = read_ecc[0] | (read_ecc[1] << 8) |
 					  (read_ecc[2] << 16);
 	u_int32_t ecc_calc = calc_ecc[0] | (calc_ecc[1] << 8) |
 					  (calc_ecc[2] << 16);
 	u_int32_t diff = ecc_calc ^ ecc_nand;

 	if (diff) {
 		if ((((diff >> 12) ^ diff) & 0xfff) == 0xfff) {
 			/* Correctable error */
 			if ((diff >> (12 + 3)) < this->ecc.size) {
 				uint8_t find_bit = 1 << ((diff >> 12) & 7);
 				uint32_t find_byte = diff >> (12 + 3);

 				dat[find_byte] ^= find_bit;
 				MTDDEBUG(MTD_DEBUG_LEVEL0, "Correcting single "
 					 "bit ECC error at offset: %d, bit: "
 					 "%d\n", find_byte, find_bit);
 				return 1;
 			} else {
 				return -1;
 			}
 		} else if (!(diff & (diff - 1))) {
 			/* Single bit ECC error in the ECC itself,
 			   nothing to fix */
 			MTDDEBUG(MTD_DEBUG_LEVEL0, "Single bit ECC error in "
 				 "ECC.\n");
 			return 1;
 		} else {
 			/* Uncorrectable error */
 			MTDDEBUG(MTD_DEBUG_LEVEL0, "ECC UNCORRECTED_ERROR 1\n");
 			return -1;
 		}
 	}
 	return 0;
 }
 #endif /* CONFIG_SYS_NAND_HW_ECC */

 #ifdef CONFIG_SYS_NAND_4BIT_HW_ECC_OOBFIRST
 static struct nand_ecclayout nand_davinci_4bit_layout_oobfirst = {
 #if defined(CONFIG_SYS_NAND_PAGE_2K)
 	.eccbytes = 40,
 #ifdef CONFIG_NAND_6BYTES_OOB_FREE_10BYTES_ECC
 	.eccpos = {
 		6,   7,  8,  9, 10,	11, 12, 13, 14, 15,
 		22, 23, 24, 25, 26,	27, 28, 29, 30, 31,
 		38, 39, 40, 41, 42,	43, 44, 45, 46, 47,
 		54, 55, 56, 57, 58,	59, 60, 61, 62, 63,
 	},
 	.oobfree = {
 		{2, 4}, {16, 6}, {32, 6}, {48, 6},
 	},
 #else
 	.eccpos = {
 		24, 25, 26, 27, 28,
 		29, 30, 31, 32, 33, 34, 35, 36, 37, 38,
 		39, 40, 41, 42, 43, 44, 45, 46, 47, 48,
 		49, 50, 51, 52, 53, 54, 55, 56, 57, 58,
 		59, 60, 61, 62, 63,
 		},
 	.oobfree = {
 		{.offset = 2, .length = 22, },
 	},
 #endif	/* #ifdef CONFIG_NAND_6BYTES_OOB_FREE_10BYTES_ECC */
 #elif defined(CONFIG_SYS_NAND_PAGE_4K)
 	.eccbytes = 80,
 	.eccpos = {
 		48, 49, 50, 51, 52, 53, 54, 55, 56, 57,
 		58, 59, 60, 61, 62, 63,	64, 65, 66, 67,
 		68, 69, 70, 71, 72, 73, 74, 75, 76, 77,
 		78, 79,	80, 81, 82, 83,	84, 85, 86, 87,
 		88, 89, 90, 91, 92, 93,	94, 95, 96, 97,
 		98, 99, 100, 101, 102, 103, 104, 105, 106, 107,
 		108, 109, 110, 111, 112, 113, 114, 115, 116, 117,
 		118, 119, 120, 121, 122, 123, 124, 125, 126, 127,
 		},
 	.oobfree = {
 		{.offset = 2, .length = 46, },
 	},
 #endif
 };

 static void nand_davinci_4bit_enable_hwecc(struct mtd_info *mtd, int mode)
 {
 	u32 val;

 	switch (mode) {
 	case NAND_ECC_WRITE:
 	case NAND_ECC_READ:
 		/*
 		 * Start a new ECC calculation for reading or writing 512 bytes
 		 * of data.
 		 */
 		val = __raw_readl(&davinci_emif_regs->nandfcr);
 		val &= ~DAVINCI_NANDFCR_4BIT_ECC_SEL_MASK;
 		val |= DAVINCI_NANDFCR_NAND_ENABLE(CONFIG_SYS_NAND_CS);
 		val |= DAVINCI_NANDFCR_4BIT_ECC_SEL(CONFIG_SYS_NAND_CS);
 		val |= DAVINCI_NANDFCR_4BIT_ECC_START;
 		__raw_writel(val, &davinci_emif_regs->nandfcr);
 		break;
 	case NAND_ECC_READSYN:
 		val = __raw_readl(&davinci_emif_regs->nand4bitecc[0]);
 		break;
 	default:
 		break;
 	}
 }

 static u32 nand_davinci_4bit_readecc(struct mtd_info *mtd, unsigned int ecc[4])
 {
 	int i;

 	for (i = 0; i < 4; i++) {
 		ecc[i] = __raw_readl(&davinci_emif_regs->nand4bitecc[i]) &
 			NAND_4BITECC_MASK;
 	}

 	return 0;
 }

 static int nand_davinci_4bit_calculate_ecc(struct mtd_info *mtd,
 					   const uint8_t *dat,
 					   uint8_t *ecc_code)
 {
 	unsigned int hw_4ecc[4];
 	unsigned int i;

 	nand_davinci_4bit_readecc(mtd, hw_4ecc);

 	/*Convert 10 bit ecc value to 8 bit */
 	for (i = 0; i < 2; i++) {
 		unsigned int hw_ecc_low = hw_4ecc[i * 2];
 		unsigned int hw_ecc_hi = hw_4ecc[(i * 2) + 1];

 		/* Take first 8 bits from val1 (count1=0) or val5 (count1=1) */
 		*ecc_code++ = hw_ecc_low & 0xFF;

 		/*
 		 * Take 2 bits as LSB bits from val1 (count1=0) or val5
 		 * (count1=1) and 6 bits from val2 (count1=0) or
 		 * val5 (count1=1)
 		 */
 		*ecc_code++ =
 		    ((hw_ecc_low >> 8) & 0x3) | ((hw_ecc_low >> 14) & 0xFC);

 		/*
 		 * Take 4 bits from val2 (count1=0) or val5 (count1=1) and
 		 * 4 bits from val3 (count1=0) or val6 (count1=1)
 		 */
 		*ecc_code++ =
 		    ((hw_ecc_low >> 22) & 0xF) | ((hw_ecc_hi << 4) & 0xF0);

 		/*
 		 * Take 6 bits from val3(count1=0) or val6 (count1=1) and
 		 * 2 bits from val4 (count1=0) or  val7 (count1=1)
 		 */
 		*ecc_code++ =
 		    ((hw_ecc_hi >> 4) & 0x3F) | ((hw_ecc_hi >> 10) & 0xC0);

 		/* Take 8 bits from val4 (count1=0) or val7 (count1=1) */
 		*ecc_code++ = (hw_ecc_hi >> 18) & 0xFF;
 	}

 	return 0;
 }

 static int nand_davinci_4bit_correct_data(struct mtd_info *mtd, uint8_t *dat,
 					  uint8_t *read_ecc, uint8_t *calc_ecc)
 {
 	int i;
 	unsigned int hw_4ecc[4];
 	unsigned int iserror;
 	unsigned short *ecc16;
 	unsigned int numerrors, erroraddress, errorvalue;
 	u32 val;

 	/*
 	 * Check for an ECC where all bytes are 0xFF.  If this is the case, we
 	 * will assume we are looking at an erased page and we should ignore
 	 * the ECC.
 	 */
 	for (i = 0; i < 10; i++) {
 		if (read_ecc[i] != 0xFF)
 			break;
 	}
 	if (i == 10)
 		return 0;

 	/* Convert 8 bit in to 10 bit */
 	ecc16 = (unsigned short *)&read_ecc[0];

 	/*
 	 * Write the parity values in the NAND Flash 4-bit ECC Load register.
 	 * Write each parity value one at a time starting from 4bit_ecc_val8
 	 * to 4bit_ecc_val1.
 	 */

 	/*Take 2 bits from 8th byte and 8 bits from 9th byte */
 	__raw_writel(((ecc16[4]) >> 6) & 0x3FF,
 			&davinci_emif_regs->nand4biteccload);

 	/* Take 4 bits from 7th byte and 6 bits from 8th byte */
 	__raw_writel((((ecc16[3]) >> 12) & 0xF) | ((((ecc16[4])) << 4) & 0x3F0),
 			&davinci_emif_regs->nand4biteccload);

 	/* Take 6 bits from 6th byte and 4 bits from 7th byte */
 	__raw_writel((ecc16[3] >> 2) & 0x3FF,
 			&davinci_emif_regs->nand4biteccload);

 	/* Take 8 bits from 5th byte and 2 bits from 6th byte */
 	__raw_writel(((ecc16[2]) >> 8) | ((((ecc16[3])) << 8) & 0x300),
 			&davinci_emif_regs->nand4biteccload);

 	/*Take 2 bits from 3rd byte and 8 bits from 4th byte */
 	__raw_writel((((ecc16[1]) >> 14) & 0x3) | ((((ecc16[2])) << 2) & 0x3FC),
 			&davinci_emif_regs->nand4biteccload);

 	/* Take 4 bits form 2nd bytes and 6 bits from 3rd bytes */
 	__raw_writel(((ecc16[1]) >> 4) & 0x3FF,
 			&davinci_emif_regs->nand4biteccload);

 	/* Take 6 bits from 1st byte and 4 bits from 2nd byte */
 	__raw_writel((((ecc16[0]) >> 10) & 0x3F) | (((ecc16[1]) << 6) & 0x3C0),
 			&davinci_emif_regs->nand4biteccload);

 	/* Take 10 bits from 0th and 1st bytes */
 	__raw_writel((ecc16[0]) & 0x3FF,
 			&davinci_emif_regs->nand4biteccload);

 	/*
 	 * Perform a dummy read to the EMIF Revision Code and Status register.
 	 * This is required to ensure time for syndrome calculation after
 	 * writing the ECC values in previous step.
 	 */

 	val = __raw_readl(&davinci_emif_regs->nandfsr);

 	/*
 	 * Read the syndrome from the NAND Flash 4-Bit ECC 1-4 registers.
 	 * A syndrome value of 0 means no bit errors. If the syndrome is
 	 * non-zero then go further otherwise return.
 	 */
 	nand_davinci_4bit_readecc(mtd, hw_4ecc);

 	if (!(hw_4ecc[0] | hw_4ecc[1] | hw_4ecc[2] | hw_4ecc[3]))
 		return 0;

 	/*
 	 * Clear any previous address calculation by doing a dummy read of an
 	 * error address register.
 	 */
 	val = __raw_readl(&davinci_emif_regs->nanderradd1);

 	/*
 	 * Set the addr_calc_st bit(bit no 13) in the NAND Flash Control
 	 * register to 1.
 	 */
 	__raw_writel(DAVINCI_NANDFCR_4BIT_CALC_START,
 			&davinci_emif_regs->nandfcr);

 	/*
 	 * Wait for the corr_state field (bits 8 to 11) in the
 	 * NAND Flash Status register to be not equal to 0x0, 0x1, 0x2, or 0x3.
 	 * Otherwise ECC calculation has not even begun and the next loop might
 	 * fail because of a false positive!
 	 */
 	i = NAND_TIMEOUT;
 	do {
 		val = __raw_readl(&davinci_emif_regs->nandfsr);
 		val &= 0xc00;
 		i--;
 	} while ((i > 0) && !val);

 	/*
 	 * Wait for the corr_state field (bits 8 to 11) in the
 	 * NAND Flash Status register to be equal to 0x0, 0x1, 0x2, or 0x3.
 	 */
 	i = NAND_TIMEOUT;
 	do {
 		val = __raw_readl(&davinci_emif_regs->nandfsr);
 		val &= 0xc00;
 		i--;
 	} while ((i > 0) && val);

 	iserror = __raw_readl(&davinci_emif_regs->nandfsr);
 	iserror &= EMIF_NANDFSR_ECC_STATE_MASK;
 	iserror = iserror >> 8;

 	/*
 	 * ECC_STATE_TOO_MANY_ERRS (0x1) means errors cannot be
 	 * corrected (five or more errors).  The number of errors
 	 * calculated (err_num field) differs from the number of errors
 	 * searched.  ECC_STATE_ERR_CORR_COMP_P (0x2) means error
 	 * correction complete (errors on bit 8 or 9).
 	 * ECC_STATE_ERR_CORR_COMP_N (0x3) means error correction
 	 * complete (error exists).
 	 */

 	if (iserror == ECC_STATE_NO_ERR) {
 		val = __raw_readl(&davinci_emif_regs->nanderrval1);
 		return 0;
 	} else if (iserror == ECC_STATE_TOO_MANY_ERRS) {
 		val = __raw_readl(&davinci_emif_regs->nanderrval1);
 		return -1;
 	}

 	numerrors = ((__raw_readl(&davinci_emif_regs->nandfsr) >> 16)
 			& 0x3) + 1;

 	/* Read the error address, error value and correct */
 	for (i = 0; i < numerrors; i++) {
 		if (i > 1) {
 			erroraddress =
 			    ((__raw_readl(&davinci_emif_regs->nanderradd2) >>
 			      (16 * (i & 1))) & 0x3FF);
 			erroraddress = ((512 + 7) - erroraddress);
 			errorvalue =
 			    ((__raw_readl(&davinci_emif_regs->nanderrval2) >>
 			      (16 * (i & 1))) & 0xFF);
 		} else {
 			erroraddress =
 			    ((__raw_readl(&davinci_emif_regs->nanderradd1) >>
 			      (16 * (i & 1))) & 0x3FF);
 			erroraddress = ((512 + 7) - erroraddress);
 			errorvalue =
 			    ((__raw_readl(&davinci_emif_regs->nanderrval1) >>
 			      (16 * (i & 1))) & 0xFF);
 		}
 		/* xor the corrupt data with error value */
 		if (erroraddress < 512)
 			dat[erroraddress] ^= errorvalue;
 	}

 	return numerrors;
 }
 #endif /* CONFIG_SYS_NAND_4BIT_HW_ECC_OOBFIRST */

 static int nand_davinci_dev_ready(struct mtd_info *mtd)
 {
 	return __raw_readl(&davinci_emif_regs->nandfsr) & 0x1;
 }

 static void nand_flash_init(void)
 {
 	/* This is for DM6446 EVM and *very* similar.  DO NOT GROW THIS!
 	 * Instead, have your board_init() set EMIF timings, based on its
 	 * knowledge of the clocks and what devices are hooked up ... and
 	 * don't even do that unless no UBL handled it.
 	 */
 #ifdef CONFIG_SOC_DM644X
 	u_int32_t	acfg1 = 0x3ffffffc;

 	/*------------------------------------------------------------------*
 	 *  NAND FLASH CHIP TIMEOUT @ 459 MHz                               *
 	 *                                                                  *
 	 *  AEMIF.CLK freq   = PLL1/6 = 459/6 = 76.5 MHz                    *
 	 *  AEMIF.CLK period = 1/76.5 MHz = 13.1 ns                         *
 	 *                                                                  *
 	 *------------------------------------------------------------------*/
 	 acfg1 = 0
 		| (0 << 31)	/* selectStrobe */
 		| (0 << 30)	/* extWait */
 		| (1 << 26)	/* writeSetup	10 ns */
 		| (3 << 20)	/* writeStrobe	40 ns */
 		| (1 << 17)	/* writeHold	10 ns */
 		| (1 << 13)	/* readSetup	10 ns */
 		| (5 << 7)	/* readStrobe	60 ns */
 		| (1 << 4)	/* readHold	10 ns */
 		| (3 << 2)	/* turnAround	?? ns */
 		| (0 << 0)	/* asyncSize	8-bit bus */
 		;

 	__raw_writel(acfg1, &davinci_emif_regs->ab1cr); /* CS2 */

 	/* NAND flash on CS2 */
 	__raw_writel(0x00000101, &davinci_emif_regs->nandfcr);
 #endif
 }

 void davinci_nand_init(struct nand_chip *nand)
 {
 	nand->chip_delay  = 0;
 #ifdef CONFIG_SYS_NAND_USE_FLASH_BBT
 	nand->bbt_options	  |= NAND_BBT_USE_FLASH;
 #endif
 #ifdef CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
 	nand->options	  |= NAND_NO_SUBPAGE_WRITE;
 #endif
 #ifdef CONFIG_SYS_NAND_HW_ECC
 	nand->ecc.mode = NAND_ECC_HW;
 	nand->ecc.size = 512;
 	nand->ecc.bytes = 3;
 	nand->ecc.strength = 1;
 	nand->ecc.calculate = nand_davinci_calculate_ecc;
 	nand->ecc.correct  = nand_davinci_correct_data;
 	nand->ecc.hwctl  = nand_davinci_enable_hwecc;
 #else
 	nand->ecc.mode = NAND_ECC_SOFT;
 #endif /* CONFIG_SYS_NAND_HW_ECC */
 #ifdef CONFIG_SYS_NAND_4BIT_HW_ECC_OOBFIRST
 	nand->ecc.mode = NAND_ECC_HW_OOB_FIRST;
 	nand->ecc.size = 512;
 	nand->ecc.bytes = 10;
 	nand->ecc.strength = 4;
 	nand->ecc.calculate = nand_davinci_4bit_calculate_ecc;
 	nand->ecc.correct = nand_davinci_4bit_correct_data;
 	nand->ecc.hwctl = nand_davinci_4bit_enable_hwecc;
 	nand->ecc.layout = &nand_davinci_4bit_layout_oobfirst;
 #endif
 	/* Set address of hardware control function */
 	nand->cmd_ctrl = nand_davinci_hwcontrol;

 	nand->read_buf = nand_davinci_read_buf;
 	nand->write_buf = nand_davinci_write_buf;

 	nand->dev_ready = nand_davinci_dev_ready;

 	nand_flash_init();
 }

 int board_nand_init(struct nand_chip *chip) __attribute__((weak));

 int board_nand_init(struct nand_chip *chip)
 {
 	davinci_nand_init(chip);
 	return 0;
 }
	/*
	* NAND driver for TI DaVinci based boards.
	*
	* Copyright (C) 2007 Sergey Kubushyn <ksi@koi8.net>
	*
	* Based on Linux DaVinci NAND driver by TI. Original copyright follows:
	*/

	/*
	*
	* linux/drivers/mtd/nand/nand_davinci.c
	*
	* NAND Flash Driver
	*
	* Copyright (C) 2006 Texas Instruments.
	*
	* ----------------------------------------------------------------------------
	*
	* SPDX-License-Identifier: GPL-2.0+
	*
	* ----------------------------------------------------------------------------
	*
	* Overview:
	* This is a device driver for the NAND flash device found on the
	* DaVinci board which utilizes the Samsung k9k2g08 part.
	*
	Modifications:
	ver. 1.0: Feb 2005, Vinod/Sudhakar
	-
	*/

	#include <common.h>
	#include <asm/io.h>
	#include <nand.h>
	#include <asm/ti-common/davinci_nand.h>

	/* Definitions for 4-bit hardware ECC */
	#define NAND_TIMEOUT 10240
	#define NAND_ECC_BUSY 0xC
	#define NAND_4BITECC_MASK 0x03FF03FF
	#define EMIF_NANDFSR_ECC_STATE_MASK 0x00000F00
	#define ECC_STATE_NO_ERR 0x0
	#define ECC_STATE_TOO_MANY_ERRS 0x1
	#define ECC_STATE_ERR_CORR_COMP_P 0x2
	#define ECC_STATE_ERR_CORR_COMP_N 0x3

	/*
	* Exploit the little endianness of the ARM to do multi-byte transfers
	* per device read. This can perform over twice as quickly as individual
	* byte transfers when buffer alignment is conducive.
	*
	* NOTE: This only works if the NAND is not connected to the 2 LSBs of
	* the address bus. On Davinci EVM platforms this has always been true.
	*/
	static void nand_davinci_read_buf(struct mtd_info mtd, uint8_t buf, int len)
	{
	struct nand_chip *chip = mtd->priv;
	const u32 *nand = chip->IO_ADDR_R;

	/* Make sure that buf is 32 bit aligned */
	if (((int)buf & 0x3) != 0) {
	if (((int)buf & 0x1) != 0) {
	if (len) {
	*buf = readb(nand);
	buf += 1;
	len--;
	}
	}

	if (((int)buf & 0x3) != 0) {
	if (len >= 2) {
	(u16 )buf = readw(nand);
	buf += 2;
	len -= 2;
	}
	}
	}

	/* copy aligned data */
	while (len >= 4) {
	(u32 )buf = __raw_readl(nand);
	buf += 4;
	len -= 4;
	}

	/* mop up any remaining bytes */
	if (len) {
	if (len >= 2) {
	(u16 )buf = readw(nand);
	buf += 2;
	len -= 2;
	}

	if (len)
	*buf = readb(nand);
	}
	}

	static void nand_davinci_write_buf(struct mtd_info mtd, const uint8_t buf,
	int len)
	{
	struct nand_chip *chip = mtd->priv;
	const u32 *nand = chip->IO_ADDR_W;

	/* Make sure that buf is 32 bit aligned */
	if (((int)buf & 0x3) != 0) {
	if (((int)buf & 0x1) != 0) {
	if (len) {
	writeb(*buf, nand);
	buf += 1;
	len--;
	}
	}

	if (((int)buf & 0x3) != 0) {
	if (len >= 2) {
	writew((u16 )buf, nand);
	buf += 2;
	len -= 2;
	}
	}
	}

	/* copy aligned data */
	while (len >= 4) {
	__raw_writel((u32 )buf, nand);
	buf += 4;
	len -= 4;
	}

	/* mop up any remaining bytes */
	if (len) {
	if (len >= 2) {
	writew((u16 )buf, nand);
	buf += 2;
	len -= 2;
	}

	if (len)
	writeb(*buf, nand);
	}
	}

	static void nand_davinci_hwcontrol(struct mtd_info *mtd, int cmd,
	unsigned int ctrl)
	{
	struct nand_chip *this = mtd->priv;
	u_int32_t IO_ADDR_W = (u_int32_t)this->IO_ADDR_W;

	if (ctrl & NAND_CTRL_CHANGE) {
	IO_ADDR_W &= ~(MASK_ALE\|MASK_CLE);

	if (ctrl & NAND_CLE)
	IO_ADDR_W \|= MASK_CLE;
	if (ctrl & NAND_ALE)
	IO_ADDR_W \|= MASK_ALE;
	this->IO_ADDR_W = (void __iomem *) IO_ADDR_W;
	}

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

	#ifdef CONFIG_SYS_NAND_HW_ECC

	static u_int32_t nand_davinci_readecc(struct mtd_info *mtd)
	{
	u_int32_t ecc = 0;

	ecc = __raw_readl(&(davinci_emif_regs->nandfecc[
	CONFIG_SYS_NAND_CS - 2]));

	return ecc;
	}

	static void nand_davinci_enable_hwecc(struct mtd_info *mtd, int mode)
	{
	u_int32_t val;

	/* reading the ECC result register resets the ECC calculation */
	nand_davinci_readecc(mtd);

	val = __raw_readl(&davinci_emif_regs->nandfcr);
	val \|= DAVINCI_NANDFCR_NAND_ENABLE(CONFIG_SYS_NAND_CS);
	val \|= DAVINCI_NANDFCR_1BIT_ECC_START(CONFIG_SYS_NAND_CS);
	__raw_writel(val, &davinci_emif_regs->nandfcr);
	}

	static int nand_davinci_calculate_ecc(struct mtd_info mtd, const u_char dat,
	u_char *ecc_code)
	{
	u_int32_t tmp;

	tmp = nand_davinci_readecc(mtd);

	/* Squeeze 4 bytes ECC into 3 bytes by removing RESERVED bits
	* and shifting. RESERVED bits are 31 to 28 and 15 to 12. */
	tmp = (tmp & 0x00000fff) \| ((tmp & 0x0fff0000) >> 4);

	/* Invert so that erased block ECC is correct */
	tmp = ~tmp;

	*ecc_code++ = tmp;
	*ecc_code++ = tmp >> 8;
	*ecc_code++ = tmp >> 16;

	/* NOTE: the above code matches mainline Linux:
	* .PQR.stu ==> ~PQRstu
	*
	* MontaVista/TI kernels encode those bytes differently, use
	* complicated (and allegedly sometimes-wrong) correction code,
	* and usually shipped with U-Boot that uses software ECC:
	* .PQR.stu ==> PsQRtu
	*
	* If you need MV/TI compatible NAND I/O in U-Boot, it should
	* be possible to (a) change the mangling above, (b) reverse
	* that mangling in nand_davinci_correct_data() below.
	*/

	return 0;
	}

	static int nand_davinci_correct_data(struct mtd_info mtd, u_char dat,
	u_char read_ecc, u_char calc_ecc)
	{
	struct nand_chip *this = mtd->priv;
	u_int32_t ecc_nand = read_ecc[0] \| (read_ecc[1] << 8) \|
	(read_ecc[2] << 16);
	u_int32_t ecc_calc = calc_ecc[0] \| (calc_ecc[1] << 8) \|
	(calc_ecc[2] << 16);
	u_int32_t diff = ecc_calc ^ ecc_nand;

	if (diff) {
	if ((((diff >> 12) ^ diff) & 0xfff) == 0xfff) {
	/* Correctable error */
	if ((diff >> (12 + 3)) < this->ecc.size) {
	uint8_t find_bit = 1 << ((diff >> 12) & 7);
	uint32_t find_byte = diff >> (12 + 3);

	dat[find_byte] ^= find_bit;
	MTDDEBUG(MTD_DEBUG_LEVEL0, "Correcting single "
	"bit ECC error at offset: %d, bit: "
	"%d\n", find_byte, find_bit);
	return 1;
	} else {
	return -1;
	}
	} else if (!(diff & (diff - 1))) {
	/* Single bit ECC error in the ECC itself,
	nothing to fix */
	MTDDEBUG(MTD_DEBUG_LEVEL0, "Single bit ECC error in "
	"ECC.\n");
	return 1;
	} else {
	/* Uncorrectable error */
	MTDDEBUG(MTD_DEBUG_LEVEL0, "ECC UNCORRECTED_ERROR 1\n");
	return -1;
	}
	}
	return 0;
	}
	#endif /* CONFIG_SYS_NAND_HW_ECC */

	#ifdef CONFIG_SYS_NAND_4BIT_HW_ECC_OOBFIRST
	static struct nand_ecclayout nand_davinci_4bit_layout_oobfirst = {
	#if defined(CONFIG_SYS_NAND_PAGE_2K)
	.eccbytes = 40,
	#ifdef CONFIG_NAND_6BYTES_OOB_FREE_10BYTES_ECC
	.eccpos = {
	6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
	22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
	38, 39, 40, 41, 42, 43, 44, 45, 46, 47,
	54, 55, 56, 57, 58, 59, 60, 61, 62, 63,
	},
	.oobfree = {
	{2, 4}, {16, 6}, {32, 6}, {48, 6},
	},
	#else
	.eccpos = {
	24, 25, 26, 27, 28,
	29, 30, 31, 32, 33, 34, 35, 36, 37, 38,
	39, 40, 41, 42, 43, 44, 45, 46, 47, 48,
	49, 50, 51, 52, 53, 54, 55, 56, 57, 58,
	59, 60, 61, 62, 63,
	},
	.oobfree = {
	{.offset = 2, .length = 22, },
	},
	#endif /* #ifdef CONFIG_NAND_6BYTES_OOB_FREE_10BYTES_ECC */
	#elif defined(CONFIG_SYS_NAND_PAGE_4K)
	.eccbytes = 80,
	.eccpos = {
	48, 49, 50, 51, 52, 53, 54, 55, 56, 57,
	58, 59, 60, 61, 62, 63, 64, 65, 66, 67,
	68, 69, 70, 71, 72, 73, 74, 75, 76, 77,
	78, 79, 80, 81, 82, 83, 84, 85, 86, 87,
	88, 89, 90, 91, 92, 93, 94, 95, 96, 97,
	98, 99, 100, 101, 102, 103, 104, 105, 106, 107,
	108, 109, 110, 111, 112, 113, 114, 115, 116, 117,
	118, 119, 120, 121, 122, 123, 124, 125, 126, 127,
	},
	.oobfree = {
	{.offset = 2, .length = 46, },
	},
	#endif
	};

	static void nand_davinci_4bit_enable_hwecc(struct mtd_info *mtd, int mode)
	{
	u32 val;

	switch (mode) {
	case NAND_ECC_WRITE:
	case NAND_ECC_READ:
	/*
	* Start a new ECC calculation for reading or writing 512 bytes
	* of data.
	*/
	val = __raw_readl(&davinci_emif_regs->nandfcr);
	val &= ~DAVINCI_NANDFCR_4BIT_ECC_SEL_MASK;
	val \|= DAVINCI_NANDFCR_NAND_ENABLE(CONFIG_SYS_NAND_CS);
	val \|= DAVINCI_NANDFCR_4BIT_ECC_SEL(CONFIG_SYS_NAND_CS);
	val \|= DAVINCI_NANDFCR_4BIT_ECC_START;
	__raw_writel(val, &davinci_emif_regs->nandfcr);
	break;
	case NAND_ECC_READSYN:
	val = __raw_readl(&davinci_emif_regs->nand4bitecc[0]);
	break;
	default:
	break;
	}
	}

	static u32 nand_davinci_4bit_readecc(struct mtd_info *mtd, unsigned int ecc[4])
	{
	int i;

	for (i = 0; i < 4; i++) {
	ecc[i] = __raw_readl(&davinci_emif_regs->nand4bitecc[i]) &
	NAND_4BITECC_MASK;
	}

	return 0;
	}

	static int nand_davinci_4bit_calculate_ecc(struct mtd_info *mtd,
	const uint8_t *dat,
	uint8_t *ecc_code)
	{
	unsigned int hw_4ecc[4];
	unsigned int i;

	nand_davinci_4bit_readecc(mtd, hw_4ecc);

	/Convert 10 bit ecc value to 8 bit /
	for (i = 0; i < 2; i++) {
	unsigned int hw_ecc_low = hw_4ecc[i * 2];
	unsigned int hw_ecc_hi = hw_4ecc[(i * 2) + 1];

	/* Take first 8 bits from val1 (count1=0) or val5 (count1=1) */
	*ecc_code++ = hw_ecc_low & 0xFF;

	/*
	* Take 2 bits as LSB bits from val1 (count1=0) or val5
	* (count1=1) and 6 bits from val2 (count1=0) or
	* val5 (count1=1)
	*/
	*ecc_code++ =
	((hw_ecc_low >> 8) & 0x3) \| ((hw_ecc_low >> 14) & 0xFC);

	/*
	* Take 4 bits from val2 (count1=0) or val5 (count1=1) and
	* 4 bits from val3 (count1=0) or val6 (count1=1)
	*/
	*ecc_code++ =
	((hw_ecc_low >> 22) & 0xF) \| ((hw_ecc_hi << 4) & 0xF0);

	/*
	* Take 6 bits from val3(count1=0) or val6 (count1=1) and
	* 2 bits from val4 (count1=0) or val7 (count1=1)
	*/
	*ecc_code++ =
	((hw_ecc_hi >> 4) & 0x3F) \| ((hw_ecc_hi >> 10) & 0xC0);

	/* Take 8 bits from val4 (count1=0) or val7 (count1=1) */
	*ecc_code++ = (hw_ecc_hi >> 18) & 0xFF;
	}

	return 0;
	}

	static int nand_davinci_4bit_correct_data(struct mtd_info mtd, uint8_t dat,
	uint8_t read_ecc, uint8_t calc_ecc)
	{
	int i;
	unsigned int hw_4ecc[4];
	unsigned int iserror;
	unsigned short *ecc16;
	unsigned int numerrors, erroraddress, errorvalue;
	u32 val;

	/*
	* Check for an ECC where all bytes are 0xFF. If this is the case, we
	* will assume we are looking at an erased page and we should ignore
	* the ECC.
	*/
	for (i = 0; i < 10; i++) {
	if (read_ecc[i] != 0xFF)
	break;
	}
	if (i == 10)
	return 0;

	/* Convert 8 bit in to 10 bit */
	ecc16 = (unsigned short *)&read_ecc[0];

	/*
	* Write the parity values in the NAND Flash 4-bit ECC Load register.
	* Write each parity value one at a time starting from 4bit_ecc_val8
	* to 4bit_ecc_val1.
	*/

	/Take 2 bits from 8th byte and 8 bits from 9th byte /
	__raw_writel(((ecc16[4]) >> 6) & 0x3FF,
	&davinci_emif_regs->nand4biteccload);

	/* Take 4 bits from 7th byte and 6 bits from 8th byte */
	__raw_writel((((ecc16[3]) >> 12) & 0xF) \| ((((ecc16[4])) << 4) & 0x3F0),
	&davinci_emif_regs->nand4biteccload);

	/* Take 6 bits from 6th byte and 4 bits from 7th byte */
	__raw_writel((ecc16[3] >> 2) & 0x3FF,
	&davinci_emif_regs->nand4biteccload);

	/* Take 8 bits from 5th byte and 2 bits from 6th byte */
	__raw_writel(((ecc16[2]) >> 8) \| ((((ecc16[3])) << 8) & 0x300),
	&davinci_emif_regs->nand4biteccload);

	/Take 2 bits from 3rd byte and 8 bits from 4th byte /
	__raw_writel((((ecc16[1]) >> 14) & 0x3) \| ((((ecc16[2])) << 2) & 0x3FC),
	&davinci_emif_regs->nand4biteccload);

	/* Take 4 bits form 2nd bytes and 6 bits from 3rd bytes */
	__raw_writel(((ecc16[1]) >> 4) & 0x3FF,
	&davinci_emif_regs->nand4biteccload);

	/* Take 6 bits from 1st byte and 4 bits from 2nd byte */
	__raw_writel((((ecc16[0]) >> 10) & 0x3F) \| (((ecc16[1]) << 6) & 0x3C0),
	&davinci_emif_regs->nand4biteccload);

	/* Take 10 bits from 0th and 1st bytes */
	__raw_writel((ecc16[0]) & 0x3FF,
	&davinci_emif_regs->nand4biteccload);

	/*
	* Perform a dummy read to the EMIF Revision Code and Status register.
	* This is required to ensure time for syndrome calculation after
	* writing the ECC values in previous step.
	*/

	val = __raw_readl(&davinci_emif_regs->nandfsr);

	/*
	* Read the syndrome from the NAND Flash 4-Bit ECC 1-4 registers.
	* A syndrome value of 0 means no bit errors. If the syndrome is
	* non-zero then go further otherwise return.
	*/
	nand_davinci_4bit_readecc(mtd, hw_4ecc);

	if (!(hw_4ecc[0] \| hw_4ecc[1] \| hw_4ecc[2] \| hw_4ecc[3]))
	return 0;

	/*
	* Clear any previous address calculation by doing a dummy read of an
	* error address register.
	*/
	val = __raw_readl(&davinci_emif_regs->nanderradd1);

	/*
	* Set the addr_calc_st bit(bit no 13) in the NAND Flash Control
	* register to 1.
	*/
	__raw_writel(DAVINCI_NANDFCR_4BIT_CALC_START,
	&davinci_emif_regs->nandfcr);

	/*
	* Wait for the corr_state field (bits 8 to 11) in the
	* NAND Flash Status register to be not equal to 0x0, 0x1, 0x2, or 0x3.
	* Otherwise ECC calculation has not even begun and the next loop might
	* fail because of a false positive!
	*/
	i = NAND_TIMEOUT;
	do {
	val = __raw_readl(&davinci_emif_regs->nandfsr);
	val &= 0xc00;
	i--;
	} while ((i > 0) && !val);

	/*
	* Wait for the corr_state field (bits 8 to 11) in the
	* NAND Flash Status register to be equal to 0x0, 0x1, 0x2, or 0x3.
	*/
	i = NAND_TIMEOUT;
	do {
	val = __raw_readl(&davinci_emif_regs->nandfsr);
	val &= 0xc00;
	i--;
	} while ((i > 0) && val);

	iserror = __raw_readl(&davinci_emif_regs->nandfsr);
	iserror &= EMIF_NANDFSR_ECC_STATE_MASK;
	iserror = iserror >> 8;

	/*
	* ECC_STATE_TOO_MANY_ERRS (0x1) means errors cannot be
	* corrected (five or more errors). The number of errors
	* calculated (err_num field) differs from the number of errors
	* searched. ECC_STATE_ERR_CORR_COMP_P (0x2) means error
	* correction complete (errors on bit 8 or 9).
	* ECC_STATE_ERR_CORR_COMP_N (0x3) means error correction
	* complete (error exists).
	*/

	if (iserror == ECC_STATE_NO_ERR) {
	val = __raw_readl(&davinci_emif_regs->nanderrval1);
	return 0;
	} else if (iserror == ECC_STATE_TOO_MANY_ERRS) {
	val = __raw_readl(&davinci_emif_regs->nanderrval1);
	return -1;
	}

	numerrors = ((__raw_readl(&davinci_emif_regs->nandfsr) >> 16)
	& 0x3) + 1;

	/* Read the error address, error value and correct */
	for (i = 0; i < numerrors; i++) {
	if (i > 1) {
	erroraddress =
	((__raw_readl(&davinci_emif_regs->nanderradd2) >>
	(16 * (i & 1))) & 0x3FF);
	erroraddress = ((512 + 7) - erroraddress);
	errorvalue =
	((__raw_readl(&davinci_emif_regs->nanderrval2) >>
	(16 * (i & 1))) & 0xFF);
	} else {
	erroraddress =
	((__raw_readl(&davinci_emif_regs->nanderradd1) >>
	(16 * (i & 1))) & 0x3FF);
	erroraddress = ((512 + 7) - erroraddress);
	errorvalue =
	((__raw_readl(&davinci_emif_regs->nanderrval1) >>
	(16 * (i & 1))) & 0xFF);
	}
	/* xor the corrupt data with error value */
	if (erroraddress < 512)
	dat[erroraddress] ^= errorvalue;
	}

	return numerrors;
	}
	#endif /* CONFIG_SYS_NAND_4BIT_HW_ECC_OOBFIRST */

	static int nand_davinci_dev_ready(struct mtd_info *mtd)
	{
	return __raw_readl(&davinci_emif_regs->nandfsr) & 0x1;
	}

	static void nand_flash_init(void)
	{
	/* This is for DM6446 EVM and very similar. DO NOT GROW THIS!
	* Instead, have your board_init() set EMIF timings, based on its
	* knowledge of the clocks and what devices are hooked up ... and
	* don't even do that unless no UBL handled it.
	*/
	#ifdef CONFIG_SOC_DM644X
	u_int32_t acfg1 = 0x3ffffffc;

	/------------------------------------------------------------------
	* NAND FLASH CHIP TIMEOUT @ 459 MHz *
	* *
	* AEMIF.CLK freq = PLL1/6 = 459/6 = 76.5 MHz *
	* AEMIF.CLK period = 1/76.5 MHz = 13.1 ns *
	* *
	------------------------------------------------------------------/
	acfg1 = 0
	\| (0 << 31) /* selectStrobe */
	\| (0 << 30) /* extWait */
	\| (1 << 26) /* writeSetup 10 ns */
	\| (3 << 20) /* writeStrobe 40 ns */
	\| (1 << 17) /* writeHold 10 ns */
	\| (1 << 13) /* readSetup 10 ns */
	\| (5 << 7) /* readStrobe 60 ns */
	\| (1 << 4) /* readHold 10 ns */
	\| (3 << 2) /* turnAround ?? ns */
	\| (0 << 0) /* asyncSize 8-bit bus */
	;

	__raw_writel(acfg1, &davinci_emif_regs->ab1cr); /* CS2 */

	/* NAND flash on CS2 */
	__raw_writel(0x00000101, &davinci_emif_regs->nandfcr);
	#endif
	}

	void davinci_nand_init(struct nand_chip *nand)
	{
	nand->chip_delay = 0;
	#ifdef CONFIG_SYS_NAND_USE_FLASH_BBT
	nand->bbt_options \|= NAND_BBT_USE_FLASH;
	#endif
	#ifdef CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
	nand->options \|= NAND_NO_SUBPAGE_WRITE;
	#endif
	#ifdef CONFIG_SYS_NAND_HW_ECC
	nand->ecc.mode = NAND_ECC_HW;
	nand->ecc.size = 512;
	nand->ecc.bytes = 3;
	nand->ecc.strength = 1;
	nand->ecc.calculate = nand_davinci_calculate_ecc;
	nand->ecc.correct = nand_davinci_correct_data;
	nand->ecc.hwctl = nand_davinci_enable_hwecc;
	#else
	nand->ecc.mode = NAND_ECC_SOFT;
	#endif /* CONFIG_SYS_NAND_HW_ECC */
	#ifdef CONFIG_SYS_NAND_4BIT_HW_ECC_OOBFIRST
	nand->ecc.mode = NAND_ECC_HW_OOB_FIRST;
	nand->ecc.size = 512;
	nand->ecc.bytes = 10;
	nand->ecc.strength = 4;
	nand->ecc.calculate = nand_davinci_4bit_calculate_ecc;
	nand->ecc.correct = nand_davinci_4bit_correct_data;
	nand->ecc.hwctl = nand_davinci_4bit_enable_hwecc;
	nand->ecc.layout = &nand_davinci_4bit_layout_oobfirst;
	#endif
	/* Set address of hardware control function */
	nand->cmd_ctrl = nand_davinci_hwcontrol;

	nand->read_buf = nand_davinci_read_buf;
	nand->write_buf = nand_davinci_write_buf;

	nand->dev_ready = nand_davinci_dev_ready;

	nand_flash_init();
	}

	int board_nand_init(struct nand_chip *chip) __attribute__((weak));

	int board_nand_init(struct nand_chip *chip)
	{
	davinci_nand_init(chip);
	return 0;
	}