cfi_flash.c

/*
 * (C) Copyright 2002-2004
 * Brad Kemp, Seranoa Networks, Brad.Kemp@seranoa.com
 *
 * Copyright (C) 2003 Arabella Software Ltd.
 * Yuli Barcohen <yuli@arabellasw.com>
 *
 * Copyright (C) 2004
 * Ed Okerson
 *
 * Copyright (C) 2006
 * Tolunay Orkun <listmember@orkun.us>
 *
 * 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
 *
 */

/* The DEBUG define must be before common to enable debugging */
/* #define DEBUG	*/

#include <common.h>
#include <asm/processor.h>
#include <asm/io.h>
#include <asm/byteorder.h>
#include <environment.h>
#include <mtd/cfi_flash.h>

/*
 * This file implements a Common Flash Interface (CFI) driver for
 * U-Boot.
 *
 * The width of the port and the width of the chips are determined at
 * initialization.  These widths are used to calculate the address for
 * access CFI data structures.
 *
 * References
 * JEDEC Standard JESD68 - Common Flash Interface (CFI)
 * JEDEC Standard JEP137-A Common Flash Interface (CFI) ID Codes
 * Intel Application Note 646 Common Flash Interface (CFI) and Command Sets
 * Intel 290667-008 3 Volt Intel StrataFlash Memory datasheet
 * AMD CFI Specification, Release 2.0 December 1, 2001
 * AMD/Spansion Application Note: Migration from Single-byte to Three-byte
 *   Device IDs, Publication Number 25538 Revision A, November 8, 2001
 *
 * Define CONFIG_SYS_WRITE_SWAPPED_DATA, if you have to swap the Bytes between
 * reading and writing ... (yes there is such a Hardware).
 */

static uint flash_offset_cfi[2] = { FLASH_OFFSET_CFI, FLASH_OFFSET_CFI_ALT };
#ifdef CONFIG_FLASH_CFI_MTD
static uint flash_verbose = 1;
#else
#define flash_verbose 1
#endif

flash_info_t flash_info[CFI_MAX_FLASH_BANKS];	/* FLASH chips info */

/*
 * Check if chip width is defined. If not, start detecting with 8bit.
 */
#ifndef CONFIG_SYS_FLASH_CFI_WIDTH
#define CONFIG_SYS_FLASH_CFI_WIDTH	FLASH_CFI_8BIT
#endif

/*
 * 0xffff is an undefined value for the configuration register. When
 * this value is returned, the configuration register shall not be
 * written at all (default mode).
 */
static u16 cfi_flash_config_reg(int i)
{
#ifdef CONFIG_SYS_CFI_FLASH_CONFIG_REGS
	return ((u16 [])CONFIG_SYS_CFI_FLASH_CONFIG_REGS)[i];
#else
	return 0xffff;
#endif
}

#if defined(CONFIG_SYS_MAX_FLASH_BANKS_DETECT)
int cfi_flash_num_flash_banks = CONFIG_SYS_MAX_FLASH_BANKS_DETECT;
#endif

static phys_addr_t __cfi_flash_bank_addr(int i)
{
	return ((phys_addr_t [])CONFIG_SYS_FLASH_BANKS_LIST)[i];
}
phys_addr_t cfi_flash_bank_addr(int i)
	__attribute__((weak, alias("__cfi_flash_bank_addr")));

static unsigned long __cfi_flash_bank_size(int i)
{
#ifdef CONFIG_SYS_FLASH_BANKS_SIZES
	return ((unsigned long [])CONFIG_SYS_FLASH_BANKS_SIZES)[i];
#else
	return 0;
#endif
}
unsigned long cfi_flash_bank_size(int i)
	__attribute__((weak, alias("__cfi_flash_bank_size")));

static void __flash_write8(u8 value, void *addr)
{
	__raw_writeb(value, addr);
}

static void __flash_write16(u16 value, void *addr)
{
	__raw_writew(value, addr);
}

static void __flash_write32(u32 value, void *addr)
{
	__raw_writel(value, addr);
}

static void __flash_write64(u64 value, void *addr)
{
	/* No architectures currently implement __raw_writeq() */
	*(volatile u64 *)addr = value;
}

static u8 __flash_read8(void *addr)
{
	return __raw_readb(addr);
}

static u16 __flash_read16(void *addr)
{
	return __raw_readw(addr);
}

static u32 __flash_read32(void *addr)
{
	return __raw_readl(addr);
}

static u64 __flash_read64(void *addr)
{
	/* No architectures currently implement __raw_readq() */
	return *(volatile u64 *)addr;
}

#ifdef CONFIG_CFI_FLASH_USE_WEAK_ACCESSORS
void flash_write8(u8 value, void *addr)__attribute__((weak, alias("__flash_write8")));
void flash_write16(u16 value, void *addr)__attribute__((weak, alias("__flash_write16")));
void flash_write32(u32 value, void *addr)__attribute__((weak, alias("__flash_write32")));
void flash_write64(u64 value, void *addr)__attribute__((weak, alias("__flash_write64")));
u8 flash_read8(void *addr)__attribute__((weak, alias("__flash_read8")));
u16 flash_read16(void *addr)__attribute__((weak, alias("__flash_read16")));
u32 flash_read32(void *addr)__attribute__((weak, alias("__flash_read32")));
u64 flash_read64(void *addr)__attribute__((weak, alias("__flash_read64")));
#else
#define flash_write8	__flash_write8
#define flash_write16	__flash_write16
#define flash_write32	__flash_write32
#define flash_write64	__flash_write64
#define flash_read8	__flash_read8
#define flash_read16	__flash_read16
#define flash_read32	__flash_read32
#define flash_read64	__flash_read64
#endif

/*-----------------------------------------------------------------------
 */
#if defined(CONFIG_ENV_IS_IN_FLASH) || defined(CONFIG_ENV_ADDR_REDUND) || (CONFIG_SYS_MONITOR_BASE >= CONFIG_SYS_FLASH_BASE)
flash_info_t *flash_get_info(ulong base)
{
	int i;
	flash_info_t *info = NULL;

	for (i = 0; i < CONFIG_SYS_MAX_FLASH_BANKS; i++) {
		info = & flash_info[i];
		if (info->size && info->start[0] <= base &&
		    base <= info->start[0] + info->size - 1)
			break;
	}

	return info;
}
#endif

unsigned long flash_sector_size(flash_info_t *info, flash_sect_t sect)
{
	if (sect != (info->sector_count - 1))
		return info->start[sect + 1] - info->start[sect];
	else
		return info->start[0] + info->size - info->start[sect];
}

/*-----------------------------------------------------------------------
 * create an address based on the offset and the port width
 */
static inline void *
flash_map (flash_info_t * info, flash_sect_t sect, uint offset)
{
	unsigned int byte_offset = offset * info->portwidth;

	return (void *)(info->start[sect] + byte_offset);
}

static inline void flash_unmap(flash_info_t *info, flash_sect_t sect,
		unsigned int offset, void *addr)
{
}

/*-----------------------------------------------------------------------
 * make a proper sized command based on the port and chip widths
 */
static void flash_make_cmd(flash_info_t *info, u32 cmd, void *cmdbuf)
{
	int i;
	int cword_offset;
	int cp_offset;
#if defined(__LITTLE_ENDIAN) || defined(CONFIG_SYS_WRITE_SWAPPED_DATA)
	u32 cmd_le = cpu_to_le32(cmd);
#endif
	uchar val;
	uchar *cp = (uchar *) cmdbuf;

	for (i = info->portwidth; i > 0; i--){
		cword_offset = (info->portwidth-i)%info->chipwidth;
#if defined(__LITTLE_ENDIAN) || defined(CONFIG_SYS_WRITE_SWAPPED_DATA)
		cp_offset = info->portwidth - i;
		val = *((uchar*)&cmd_le + cword_offset);
#else
		cp_offset = i - 1;
		val = *((uchar*)&cmd + sizeof(u32) - cword_offset - 1);
#endif
		cp[cp_offset] = (cword_offset >= sizeof(u32)) ? 0x00 : val;
	}
}

#ifdef DEBUG
/*-----------------------------------------------------------------------
 * Debug support
 */
static void print_longlong (char *str, unsigned long long data)
{
	int i;
	char *cp;

	cp = (char *) &data;
	for (i = 0; i < 8; i++)
		sprintf (&str[i * 2], "%2.2x", *cp++);
}

static void flash_printqry (struct cfi_qry *qry)
{
	u8 *p = (u8 *)qry;
	int x, y;

	for (x = 0; x < sizeof(struct cfi_qry); x += 16) {
		debug("%02x : ", x);
		for (y = 0; y < 16; y++)
			debug("%2.2x ", p[x + y]);
		debug(" ");
		for (y = 0; y < 16; y++) {
			unsigned char c = p[x + y];
			if (c >= 0x20 && c <= 0x7e)
				debug("%c", c);
			else
				debug(".");
		}
		debug("\n");
	}
}
#endif


/*-----------------------------------------------------------------------
 * read a character at a port width address
 */
static inline uchar flash_read_uchar (flash_info_t * info, uint offset)
{
	uchar *cp;
	uchar retval;

	cp = flash_map (info, 0, offset);
#if defined(__LITTLE_ENDIAN) || defined(CONFIG_SYS_WRITE_SWAPPED_DATA)
	retval = flash_read8(cp);
#else
	retval = flash_read8(cp + info->portwidth - 1);
#endif
	flash_unmap (info, 0, offset, cp);
	return retval;
}

/*-----------------------------------------------------------------------
 * read a word at a port width address, assume 16bit bus
 */
static inline ushort flash_read_word (flash_info_t * info, uint offset)
{
	ushort *addr, retval;

	addr = flash_map (info, 0, offset);
	retval = flash_read16 (addr);
	flash_unmap (info, 0, offset, addr);
	return retval;
}


/*-----------------------------------------------------------------------
 * read a long word by picking the least significant byte of each maximum
 * port size word. Swap for ppc format.
 */
static ulong flash_read_long (flash_info_t * info, flash_sect_t sect,
			      uint offset)
{
	uchar *addr;
	ulong retval;

#ifdef DEBUG
	int x;
#endif
	addr = flash_map (info, sect, offset);

#ifdef DEBUG
	debug ("long addr is at %p info->portwidth = %d\n", addr,
	       info->portwidth);
	for (x = 0; x < 4 * info->portwidth; x++) {
		debug ("addr[%x] = 0x%x\n", x, flash_read8(addr + x));
	}
#endif
#if defined(__LITTLE_ENDIAN) || defined(CONFIG_SYS_WRITE_SWAPPED_DATA)
	retval = ((flash_read8(addr) << 16) |
		  (flash_read8(addr + info->portwidth) << 24) |
		  (flash_read8(addr + 2 * info->portwidth)) |
		  (flash_read8(addr + 3 * info->portwidth) << 8));
#else
	retval = ((flash_read8(addr + 2 * info->portwidth - 1) << 24) |
		  (flash_read8(addr + info->portwidth - 1) << 16) |
		  (flash_read8(addr + 4 * info->portwidth - 1) << 8) |
		  (flash_read8(addr + 3 * info->portwidth - 1)));
#endif
	flash_unmap(info, sect, offset, addr);

	return retval;
}

/*
 * Write a proper sized command to the correct address
 */
void flash_write_cmd (flash_info_t * info, flash_sect_t sect,
		      uint offset, u32 cmd)
{

	void *addr;
	cfiword_t cword;

	addr = flash_map (info, sect, offset);
	flash_make_cmd (info, cmd, &cword);
	switch (info->portwidth) {
	case FLASH_CFI_8BIT:
		debug ("fwc addr %p cmd %x %x 8bit x %d bit\n", addr, cmd,
		       cword.c, info->chipwidth << CFI_FLASH_SHIFT_WIDTH);
		flash_write8(cword.c, addr);
		break;
	case FLASH_CFI_16BIT:
		debug ("fwc addr %p cmd %x %4.4x 16bit x %d bit\n", addr,
		       cmd, cword.w,
		       info->chipwidth << CFI_FLASH_SHIFT_WIDTH);
		flash_write16(cword.w, addr);
		break;
	case FLASH_CFI_32BIT:
		debug ("fwc addr %p cmd %x %8.8lx 32bit x %d bit\n", addr,
		       cmd, cword.l,
		       info->chipwidth << CFI_FLASH_SHIFT_WIDTH);
		flash_write32(cword.l, addr);
		break;
	case FLASH_CFI_64BIT:
#ifdef DEBUG
		{
			char str[20];

			print_longlong (str, cword.ll);

			debug ("fwrite addr %p cmd %x %s 64 bit x %d bit\n",
			       addr, cmd, str,
			       info->chipwidth << CFI_FLASH_SHIFT_WIDTH);
		}
#endif
		flash_write64(cword.ll, addr);
		break;
	}

	/* Ensure all the instructions are fully finished */
	sync();

	flash_unmap(info, sect, offset, addr);
}

static void flash_unlock_seq (flash_info_t * info, flash_sect_t sect)
{
	flash_write_cmd (info, sect, info->addr_unlock1, AMD_CMD_UNLOCK_START);
	flash_write_cmd (info, sect, info->addr_unlock2, AMD_CMD_UNLOCK_ACK);
}

/*-----------------------------------------------------------------------
 */
static int flash_isequal (flash_info_t * info, flash_sect_t sect,
			  uint offset, uchar cmd)
{
	void *addr;
	cfiword_t cword;
	int retval;

	addr = flash_map (info, sect, offset);
	flash_make_cmd (info, cmd, &cword);

	debug ("is= cmd %x(%c) addr %p ", cmd, cmd, addr);
	switch (info->portwidth) {
	case FLASH_CFI_8BIT:
		debug ("is= %x %x\n", flash_read8(addr), cword.c);
		retval = (flash_read8(addr) == cword.c);
		break;
	case FLASH_CFI_16BIT:
		debug ("is= %4.4x %4.4x\n", flash_read16(addr), cword.w);
		retval = (flash_read16(addr) == cword.w);
		break;
	case FLASH_CFI_32BIT:
		debug ("is= %8.8x %8.8lx\n", flash_read32(addr), cword.l);
		retval = (flash_read32(addr) == cword.l);
		break;
	case FLASH_CFI_64BIT:
#ifdef DEBUG
		{
			char str1[20];
			char str2[20];

			print_longlong (str1, flash_read64(addr));
			print_longlong (str2, cword.ll);
			debug ("is= %s %s\n", str1, str2);
		}
#endif
		retval = (flash_read64(addr) == cword.ll);
		break;
	default:
		retval = 0;
		break;
	}
	flash_unmap(info, sect, offset, addr);

	return retval;
}

/*-----------------------------------------------------------------------
 */
static int flash_isset (flash_info_t * info, flash_sect_t sect,
			uint offset, uchar cmd)
{
	void *addr;
	cfiword_t cword;
	int retval;

	addr = flash_map (info, sect, offset);
	flash_make_cmd (info, cmd, &cword);
	switch (info->portwidth) {
	case FLASH_CFI_8BIT:
		retval = ((flash_read8(addr) & cword.c) == cword.c);
		break;
	case FLASH_CFI_16BIT:
		retval = ((flash_read16(addr) & cword.w) == cword.w);
		break;
	case FLASH_CFI_32BIT:
		retval = ((flash_read32(addr) & cword.l) == cword.l);
		break;
	case FLASH_CFI_64BIT:
		retval = ((flash_read64(addr) & cword.ll) == cword.ll);
		break;
	default:
		retval = 0;
		break;
	}
	flash_unmap(info, sect, offset, addr);

	return retval;
}

/*-----------------------------------------------------------------------
 */
static int flash_toggle (flash_info_t * info, flash_sect_t sect,
			 uint offset, uchar cmd)
{
	void *addr;
	cfiword_t cword;
	int retval;

	addr = flash_map (info, sect, offset);
	flash_make_cmd (info, cmd, &cword);
	switch (info->portwidth) {
	case FLASH_CFI_8BIT:
		retval = flash_read8(addr) != flash_read8(addr);
		break;
	case FLASH_CFI_16BIT:
		retval = flash_read16(addr) != flash_read16(addr);
		break;
	case FLASH_CFI_32BIT:
		retval = flash_read32(addr) != flash_read32(addr);
		break;
	case FLASH_CFI_64BIT:
		retval = ( (flash_read32( addr ) != flash_read32( addr )) ||
			   (flash_read32(addr+4) != flash_read32(addr+4)) );
		break;
	default:
		retval = 0;
		break;
	}
	flash_unmap(info, sect, offset, addr);

	return retval;
}

/*
 * flash_is_busy - check to see if the flash is busy
 *
 * This routine checks the status of the chip and returns true if the
 * chip is busy.
 */
static int flash_is_busy (flash_info_t * info, flash_sect_t sect)
{
	int retval;

	switch (info->vendor) {
	case CFI_CMDSET_INTEL_PROG_REGIONS:
	case CFI_CMDSET_INTEL_STANDARD:
	case CFI_CMDSET_INTEL_EXTENDED:
		retval = !flash_isset (info, sect, 0, FLASH_STATUS_DONE);
		break;
	case CFI_CMDSET_AMD_STANDARD:
	case CFI_CMDSET_AMD_EXTENDED:
#ifdef CONFIG_FLASH_CFI_LEGACY
	case CFI_CMDSET_AMD_LEGACY:
#endif
		retval = flash_toggle (info, sect, 0, AMD_STATUS_TOGGLE);
		break;
	default:
		retval = 0;
	}
	debug ("flash_is_busy: %d\n", retval);
	return retval;
}

/*-----------------------------------------------------------------------
 *  wait for XSR.7 to be set. Time out with an error if it does not.
 *  This routine does not set the flash to read-array mode.
 */
static int flash_status_check (flash_info_t * info, flash_sect_t sector,
			       ulong tout, char *prompt)
{
	ulong start;

#if CONFIG_SYS_HZ != 1000
	if ((ulong)CONFIG_SYS_HZ > 100000)
		tout *= (ulong)CONFIG_SYS_HZ / 1000;  /* for a big HZ, avoid overflow */
	else
		tout = DIV_ROUND_UP(tout * (ulong)CONFIG_SYS_HZ, 1000);
#endif

	/* Wait for command completion */
#ifdef CONFIG_SYS_LOW_RES_TIMER
	reset_timer();
#endif
	start = get_timer (0);
	while (flash_is_busy (info, sector)) {
		if (get_timer (start) > tout) {
			printf ("Flash %s timeout at address %lx data %lx\n",
				prompt, info->start[sector],
				flash_read_long (info, sector, 0));
			flash_write_cmd (info, sector, 0, info->cmd_reset);
			udelay(1);
			return ERR_TIMOUT;
		}
		udelay (1);		/* also triggers watchdog */
	}
	return ERR_OK;
}

/*-----------------------------------------------------------------------
 * Wait for XSR.7 to be set, if it times out print an error, otherwise
 * do a full status check.
 *
 * This routine sets the flash to read-array mode.
 */
static int flash_full_status_check (flash_info_t * info, flash_sect_t sector,
				    ulong tout, char *prompt)
{
	int retcode;

	retcode = flash_status_check (info, sector, tout, prompt);
	switch (info->vendor) {
	case CFI_CMDSET_INTEL_PROG_REGIONS:
	case CFI_CMDSET_INTEL_EXTENDED:
	case CFI_CMDSET_INTEL_STANDARD:
		if ((retcode != ERR_OK)
		    && !flash_isequal (info, sector, 0, FLASH_STATUS_DONE)) {
			retcode = ERR_INVAL;
			printf ("Flash %s error at address %lx\n", prompt,
				info->start[sector]);
			if (flash_isset (info, sector, 0, FLASH_STATUS_ECLBS |
					 FLASH_STATUS_PSLBS)) {
				puts ("Command Sequence Error.\n");
			} else if (flash_isset (info, sector, 0,
						FLASH_STATUS_ECLBS)) {
				puts ("Block Erase Error.\n");
				retcode = ERR_NOT_ERASED;
			} else if (flash_isset (info, sector, 0,
						FLASH_STATUS_PSLBS)) {
				puts ("Locking Error\n");
			}
			if (flash_isset (info, sector, 0, FLASH_STATUS_DPS)) {
				puts ("Block locked.\n");
				retcode = ERR_PROTECTED;
			}
			if (flash_isset (info, sector, 0, FLASH_STATUS_VPENS))
				puts ("Vpp Low Error.\n");
		}
		flash_write_cmd (info, sector, 0, info->cmd_reset);
		udelay(1);
		break;
	default:
		break;
	}
	return retcode;
}

static int use_flash_status_poll(flash_info_t *info)
{
#ifdef CONFIG_SYS_CFI_FLASH_STATUS_POLL
	if (info->vendor == CFI_CMDSET_AMD_EXTENDED ||
	    info->vendor == CFI_CMDSET_AMD_STANDARD)
		return 1;
#endif
	return 0;
}

static int flash_status_poll(flash_info_t *info, void *src, void *dst,
			     ulong tout, char *prompt)
{
#ifdef CONFIG_SYS_CFI_FLASH_STATUS_POLL
	ulong start;
	int ready;

#if CONFIG_SYS_HZ != 1000
	if ((ulong)CONFIG_SYS_HZ > 100000)
		tout *= (ulong)CONFIG_SYS_HZ / 1000;  /* for a big HZ, avoid overflow */
	else
		tout = DIV_ROUND_UP(tout * (ulong)CONFIG_SYS_HZ, 1000);
#endif

	/* Wait for command completion */
#ifdef CONFIG_SYS_LOW_RES_TIMER
	reset_timer();
#endif
	start = get_timer(0);
	while (1) {
		switch (info->portwidth) {
		case FLASH_CFI_8BIT:
			ready = flash_read8(dst) == flash_read8(src);
			break;
		case FLASH_CFI_16BIT:
			ready = flash_read16(dst) == flash_read16(src);
			break;
		case FLASH_CFI_32BIT:
			ready = flash_read32(dst) == flash_read32(src);
			break;
		case FLASH_CFI_64BIT:
			ready = flash_read64(dst) == flash_read64(src);
			break;
		default:
			ready = 0;
			break;
		}
		if (ready)
			break;
		if (get_timer(start) > tout) {
			printf("Flash %s timeout at address %lx data %lx\n",
			       prompt, (ulong)dst, (ulong)flash_read8(dst));
			return ERR_TIMOUT;
		}
		udelay(1);		/* also triggers watchdog */
	}
#endif /* CONFIG_SYS_CFI_FLASH_STATUS_POLL */
	return ERR_OK;
}

/*-----------------------------------------------------------------------
 */
static void flash_add_byte (flash_info_t * info, cfiword_t * cword, uchar c)
{
#if defined(__LITTLE_ENDIAN) && !defined(CONFIG_SYS_WRITE_SWAPPED_DATA)
	unsigned short	w;
	unsigned int	l;
	unsigned long long ll;
#endif

	switch (info->portwidth) {
	case FLASH_CFI_8BIT:
		cword->c = c;
		break;
	case FLASH_CFI_16BIT:
#if defined(__LITTLE_ENDIAN) && !defined(CONFIG_SYS_WRITE_SWAPPED_DATA)
		w = c;
		w <<= 8;
		cword->w = (cword->w >> 8) | w;
#else
		cword->w = (cword->w << 8) | c;
#endif
		break;
	case FLASH_CFI_32BIT:
#if defined(__LITTLE_ENDIAN) && !defined(CONFIG_SYS_WRITE_SWAPPED_DATA)
		l = c;
		l <<= 24;
		cword->l = (cword->l >> 8) | l;
#else
		cword->l = (cword->l << 8) | c;
#endif
		break;
	case FLASH_CFI_64BIT:
#if defined(__LITTLE_ENDIAN) && !defined(CONFIG_SYS_WRITE_SWAPPED_DATA)
		ll = c;
		ll <<= 56;
		cword->ll = (cword->ll >> 8) | ll;
#else
		cword->ll = (cword->ll << 8) | c;
#endif
		break;
	}
}

/*
 * Loop through the sector table starting from the previously found sector.
 * Searches forwards or backwards, dependent on the passed address.
 */
static flash_sect_t find_sector (flash_info_t * info, ulong addr)
{
	static flash_sect_t saved_sector = 0; /* previously found sector */
	static flash_info_t *saved_info = 0; /* previously used flash bank */
	flash_sect_t sector = saved_sector;

	if ((info != saved_info) || (sector >= info->sector_count))
		sector = 0;

	while ((info->start[sector] < addr)
			&& (sector < info->sector_count - 1))
		sector++;
	while ((info->start[sector] > addr) && (sector > 0))
		/*
		 * also decrements the sector in case of an overshot
		 * in the first loop
		 */
		sector--;

	saved_sector = sector;
	saved_info = info;
	return sector;
}

/*-----------------------------------------------------------------------
 */
static int flash_write_cfiword (flash_info_t * info, ulong dest,
				cfiword_t cword)
{
	void *dstaddr = (void *)dest;
	int flag;
	flash_sect_t sect = 0;
	char sect_found = 0;

	/* Check if Flash is (sufficiently) erased */
	switch (info->portwidth) {
	case FLASH_CFI_8BIT:
		flag = ((flash_read8(dstaddr) & cword.c) == cword.c);
		break;
	case FLASH_CFI_16BIT:
		flag = ((flash_read16(dstaddr) & cword.w) == cword.w);
		break;
	case FLASH_CFI_32BIT:
		flag = ((flash_read32(dstaddr) & cword.l) == cword.l);
		break;
	case FLASH_CFI_64BIT:
		flag = ((flash_read64(dstaddr) & cword.ll) == cword.ll);
		break;
	default:
		flag = 0;
		break;
	}
	if (!flag)
		return ERR_NOT_ERASED;

	/* Disable interrupts which might cause a timeout here */
	flag = disable_interrupts ();

	switch (info->vendor) {
	case CFI_CMDSET_INTEL_PROG_REGIONS:
	case CFI_CMDSET_INTEL_EXTENDED:
	case CFI_CMDSET_INTEL_STANDARD:
		flash_write_cmd (info, 0, 0, FLASH_CMD_CLEAR_STATUS);
		flash_write_cmd (info, 0, 0, FLASH_CMD_WRITE);
		break;
	case CFI_CMDSET_AMD_EXTENDED:
	case CFI_CMDSET_AMD_STANDARD:
		sect = find_sector(info, dest);
		flash_unlock_seq (info, sect);
		flash_write_cmd (info, sect, info->addr_unlock1, AMD_CMD_WRITE);
		sect_found = 1;
		break;
#ifdef CONFIG_FLASH_CFI_LEGACY
	case CFI_CMDSET_AMD_LEGACY:
		sect = find_sector(info, dest);
		flash_unlock_seq (info, 0);
		flash_write_cmd (info, 0, info->addr_unlock1, AMD_CMD_WRITE);
		sect_found = 1;
		break;
#endif
	}

	switch (info->portwidth) {
	case FLASH_CFI_8BIT:
		flash_write8(cword.c, dstaddr);
		break;
	case FLASH_CFI_16BIT:
		flash_write16(cword.w, dstaddr);
		break;
	case FLASH_CFI_32BIT:
		flash_write32(cword.l, dstaddr);
		break;
	case FLASH_CFI_64BIT:
		flash_write64(cword.ll, dstaddr);
		break;
	}

	/* re-enable interrupts if necessary */
	if (flag)
		enable_interrupts ();

	if (!sect_found)
		sect = find_sector (info, dest);

	if (use_flash_status_poll(info))
		return flash_status_poll(info, &cword, dstaddr,
					 info->write_tout, "write");
	else
		return flash_full_status_check(info, sect,
					       info->write_tout, "write");
}

#ifdef CONFIG_SYS_FLASH_USE_BUFFER_WRITE

static int flash_write_cfibuffer (flash_info_t * info, ulong dest, uchar * cp,
				  int len)
{
	flash_sect_t sector;
	int cnt;
	int retcode;
	void *src = cp;
	void *dst = (void *)dest;
	void *dst2 = dst;
	int flag = 0;
	uint offset = 0;
	unsigned int shift;
	uchar write_cmd;

	switch (info->portwidth) {
	case FLASH_CFI_8BIT:
		shift = 0;
		break;
	case FLASH_CFI_16BIT:
		shift = 1;
		break;
	case FLASH_CFI_32BIT:
		shift = 2;
		break;
	case FLASH_CFI_64BIT:
		shift = 3;
		break;
	default:
		retcode = ERR_INVAL;
		goto out_unmap;
	}

	cnt = len >> shift;

	while ((cnt-- > 0) && (flag == 0)) {
		switch (info->portwidth) {
		case FLASH_CFI_8BIT:
			flag = ((flash_read8(dst2) & flash_read8(src)) ==
				flash_read8(src));
			src += 1, dst2 += 1;
			break;
		case FLASH_CFI_16BIT:
			flag = ((flash_read16(dst2) & flash_read16(src)) ==
				flash_read16(src));
			src += 2, dst2 += 2;
			break;
		case FLASH_CFI_32BIT:
			flag = ((flash_read32(dst2) & flash_read32(src)) ==
				flash_read32(src));
			src += 4, dst2 += 4;
			break;
		case FLASH_CFI_64BIT:
			flag = ((flash_read64(dst2) & flash_read64(src)) ==
				flash_read64(src));
			src += 8, dst2 += 8;
			break;
		}
	}
	if (!flag) {
		retcode = ERR_NOT_ERASED;
		goto out_unmap;
	}

	src = cp;
	sector = find_sector (info, dest);

	switch (info->vendor) {
	case CFI_CMDSET_INTEL_PROG_REGIONS:
	case CFI_CMDSET_INTEL_STANDARD:
	case CFI_CMDSET_INTEL_EXTENDED:
		write_cmd = (info->vendor == CFI_CMDSET_INTEL_PROG_REGIONS) ?
					FLASH_CMD_WRITE_BUFFER_PROG : FLASH_CMD_WRITE_TO_BUFFER;
		flash_write_cmd (info, sector, 0, FLASH_CMD_CLEAR_STATUS);
		flash_write_cmd (info, sector, 0, FLASH_CMD_READ_STATUS);
		flash_write_cmd (info, sector, 0, write_cmd);
		retcode = flash_status_check (info, sector,
					      info->buffer_write_tout,
					      "write to buffer");
		if (retcode == ERR_OK) {
			/* reduce the number of loops by the width of
			 * the port */
			cnt = len >> shift;
			flash_write_cmd (info, sector, 0, cnt - 1);
			while (cnt-- > 0) {
				switch (info->portwidth) {
				case FLASH_CFI_8BIT:
					flash_write8(flash_read8(src), dst);
					src += 1, dst += 1;
					break;
				case FLASH_CFI_16BIT:
					flash_write16(flash_read16(src), dst);
					src += 2, dst += 2;
					break;
				case FLASH_CFI_32BIT:
					flash_write32(flash_read32(src), dst);
					src += 4, dst += 4;
					break;
				case FLASH_CFI_64BIT:
					flash_write64(flash_read64(src), dst);
					src += 8, dst += 8;
					break;
				default:
					retcode = ERR_INVAL;
					goto out_unmap;
				}
			}
			flash_write_cmd (info, sector, 0,
					 FLASH_CMD_WRITE_BUFFER_CONFIRM);
			retcode = flash_full_status_check (
				info, sector, info->buffer_write_tout,
				"buffer write");
		}

		break;

	case CFI_CMDSET_AMD_STANDARD:
	case CFI_CMDSET_AMD_EXTENDED:
		flash_unlock_seq(info,0);

#ifdef CONFIG_FLASH_SPANSION_S29WS_N
		offset = ((unsigned long)dst - info->start[sector]) >> shift;
#endif
		flash_write_cmd(info, sector, offset, AMD_CMD_WRITE_TO_BUFFER);
		cnt = len >> shift;
		flash_write_cmd(info, sector, offset, cnt - 1);

		switch (info->portwidth) {
		case FLASH_CFI_8BIT:
			while (cnt-- > 0) {
				flash_write8(flash_read8(src), dst);
				src += 1, dst += 1;
			}
			break;
		case FLASH_CFI_16BIT:
			while (cnt-- > 0) {
				flash_write16(flash_read16(src), dst);
				src += 2, dst += 2;