board/nx823/flash.c - uboot/qsr1000 - Git at Google

 /*
  * (C) Copyright 2001
  * Kyle Harris, Nexus Technologies, Inc. kharris@nexus-tech.net
  *
  * (C) Copyright 2001
  * Wolfgang Denk, DENX Software Engineering, wd@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 <mpc8xx.h>

 DECLARE_GLOBAL_DATA_PTR;

 flash_info_t	flash_info[CONFIG_SYS_MAX_FLASH_BANKS]; /* info for FLASH chips	*/

 /*-----------------------------------------------------------------------
  * Protection Flags:
  */
 #define FLAG_PROTECT_SET	0x01
 #define FLAG_PROTECT_CLEAR	0x02

 /* Board support for 1 or 2 flash devices */
 #undef FLASH_PORT_WIDTH32
 #define FLASH_PORT_WIDTH16

 #ifdef FLASH_PORT_WIDTH16
 #define FLASH_PORT_WIDTH		ushort
 #define FLASH_PORT_WIDTHV		vu_short
 #else
 #define FLASH_PORT_WIDTH		ulong
 #define FLASH_PORT_WIDTHV		vu_long
 #endif

 #define FPW		FLASH_PORT_WIDTH
 #define FPWV	FLASH_PORT_WIDTHV

 /*-----------------------------------------------------------------------
  * Functions
  */
 static ulong flash_get_size (FPW *addr, flash_info_t *info);
 static int   write_data (flash_info_t *info, ulong dest, FPW data);
 static void  flash_get_offsets (ulong base, flash_info_t *info);

 /*-----------------------------------------------------------------------
  */

 unsigned long flash_init (void)
 {
 	volatile immap_t     *immap  = (immap_t *)CONFIG_SYS_IMMR;
 	volatile memctl8xx_t *memctl = &immap->im_memctl;
 	unsigned long size_b0;
 	int i;

 	/* Init: no FLASHes known */
 	for (i=0; i<CONFIG_SYS_MAX_FLASH_BANKS; ++i) {
 		flash_info[i].flash_id = FLASH_UNKNOWN;
 	}

 	/* Static FLASH Bank configuration here - FIXME XXX */
 	size_b0 = flash_get_size((FPW *)FLASH_BASE0_PRELIM, &flash_info[0]);

 	if (flash_info[0].flash_id == FLASH_UNKNOWN) {
 		printf ("## Unknown FLASH on Bank 0 - Size = 0x%08lx = %ld MB\n",
 			size_b0, size_b0<<20);
 	}

 	/* Remap FLASH according to real size */
 	memctl->memc_or0 = CONFIG_SYS_OR_TIMING_FLASH | (-size_b0 & 0xFFFF8000);
 	memctl->memc_br0 = (CONFIG_SYS_FLASH_BASE & BR_BA_MSK) | BR_PS_16 | BR_MS_GPCM | BR_V;

 	/* Re-do sizing to get full correct info */
 	size_b0 = flash_get_size((FPW *)CONFIG_SYS_FLASH_BASE, &flash_info[0]);

 	flash_get_offsets (CONFIG_SYS_FLASH_BASE, &flash_info[0]);

 	/* monitor protection ON by default */
 	(void)flash_protect(FLAG_PROTECT_SET,
 			    CONFIG_SYS_FLASH_BASE,
 			    CONFIG_SYS_FLASH_BASE+monitor_flash_len-1,
 			    &flash_info[0]);

 	flash_info[0].size = size_b0;

 	return (size_b0);
 }

 /*-----------------------------------------------------------------------
  */
 static void flash_get_offsets (ulong base, flash_info_t *info)
 {
 	int i;

 	if (info->flash_id == FLASH_UNKNOWN) {
 		return;
 	}

 	if ((info->flash_id & FLASH_VENDMASK) == FLASH_MAN_INTEL) {
 		for (i = 0; i < info->sector_count; i++) {
 			info->start[i] = base + (i * 0x00020000);
 		}
 	}
 }

 /*-----------------------------------------------------------------------
  */
 void flash_print_info  (flash_info_t *info)
 {
 	int i;

 	if (info->flash_id == FLASH_UNKNOWN) {
 		printf ("missing or unknown FLASH type\n");
 		return;
 	}

 	switch (info->flash_id & FLASH_VENDMASK) {
 		case FLASH_MAN_INTEL:	printf ("INTEL ");		break;
 		default:		printf ("Unknown Vendor ");	break;
 	}

 	switch (info->flash_id & FLASH_TYPEMASK) {
    case FLASH_28F320J3A:
 				printf ("28F320J3A\n"); break;
    case FLASH_28F640J3A:
 				printf ("28F640J3A\n"); break;
    case FLASH_28F128J3A:
 				printf ("28F128J3A\n"); break;
 	default:		printf ("Unknown Chip Type\n"); break;
 	}

 	printf ("  Size: %ld MB in %d Sectors\n",
 		info->size >> 20, info->sector_count);

 	printf ("  Sector Start Addresses:");
 	for (i=0; i<info->sector_count; ++i) {
 		if ((i % 5) == 0)
 			printf ("\n   ");
 		printf (" %08lX%s",
 			info->start[i],
 			info->protect[i] ? " (RO)" : "     "
 		);
 	}
 	printf ("\n");
 	return;
 }

 /*-----------------------------------------------------------------------
  */


 /*-----------------------------------------------------------------------
  */

 /*
  * The following code cannot be run from FLASH!
  */

 static ulong flash_get_size (FPW *addr, flash_info_t *info)
 {
 	FPW value;

 	/* Write auto select command: read Manufacturer ID */
 	addr[0x5555] = (FPW)0x00AA00AA;
 	addr[0x2AAA] = (FPW)0x00550055;
 	addr[0x5555] = (FPW)0x00900090;

 	value = addr[0];

    switch (value) {
    case (FPW)INTEL_MANUFACT:
       info->flash_id = FLASH_MAN_INTEL;
       break;
 	default:
 		info->flash_id = FLASH_UNKNOWN;
 		info->sector_count = 0;
 		info->size = 0;
 		addr[0] = (FPW)0x00FF00FF;      /* restore read mode */
 		return (0);			/* no or unknown flash	*/
 	}

 	value = addr[1];			/* device ID		*/

    switch (value) {
    case (FPW)INTEL_ID_28F320J3A:
       info->flash_id += FLASH_28F320J3A;
       info->sector_count = 32;
       info->size = 0x00400000;
       break;            /* => 4 MB     */

    case (FPW)INTEL_ID_28F640J3A:
       info->flash_id += FLASH_28F640J3A;
       info->sector_count = 64;
       info->size = 0x00800000;
       break;            /* => 8 MB     */

    case (FPW)INTEL_ID_28F128J3A:
       info->flash_id += FLASH_28F128J3A;
       info->sector_count = 128;
       info->size = 0x01000000;
       break;            /* => 16 MB     */

 	default:
 		info->flash_id = FLASH_UNKNOWN;
 		break;
 	}

 	if (info->sector_count > CONFIG_SYS_MAX_FLASH_SECT) {
 		printf ("** ERROR: sector count %d > max (%d) **\n",
 			info->sector_count, CONFIG_SYS_MAX_FLASH_SECT);
 		info->sector_count = CONFIG_SYS_MAX_FLASH_SECT;
 	}

 	addr[0] = (FPW)0x00FF00FF;      /* restore read mode */

 	return (info->size);
 }


 /*-----------------------------------------------------------------------
  */

 int	flash_erase (flash_info_t *info, int s_first, int s_last)
 {
 	int flag, prot, sect;
 	ulong type, start, now, last;
 	int rcode = 0;

 	if ((s_first < 0) || (s_first > s_last)) {
 		if (info->flash_id == FLASH_UNKNOWN) {
 			printf ("- missing\n");
 		} else {
 			printf ("- no sectors to erase\n");
 		}
 		return 1;
 	}

 	type = (info->flash_id & FLASH_VENDMASK);
 	if ((type != FLASH_MAN_INTEL)) {
 		printf ("Can't erase unknown flash type %08lx - aborted\n",
 			info->flash_id);
 		return 1;
 	}

 	prot = 0;
 	for (sect=s_first; sect<=s_last; ++sect) {
 		if (info->protect[sect]) {
 			prot++;
 		}
 	}

 	if (prot) {
 		printf ("- Warning: %d protected sectors will not be erased!\n",
 			prot);
 	} else {
 		printf ("\n");
 	}

 	start = get_timer (0);
 	last  = start;
 	/* Start erase on unprotected sectors */
 	for (sect = s_first; sect<=s_last; sect++) {
 		if (info->protect[sect] == 0) {	/* not protected */
 			FPWV *addr = (FPWV *)(info->start[sect]);
 			FPW status;

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

 			*addr = (FPW)0x00500050;	/* clear status register */
 			*addr = (FPW)0x00200020;	/* erase setup */
 			*addr = (FPW)0x00D000D0;	/* erase confirm */

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

 			/* wait at least 80us - let's wait 1 ms */
 			udelay (1000);

 			while (((status = *addr) & (FPW)0x00800080) != (FPW)0x00800080) {
 				if ((now=get_timer(start)) > CONFIG_SYS_FLASH_ERASE_TOUT) {
 					printf ("Timeout\n");
 					*addr = (FPW)0x00B000B0; /* suspend erase	  */
 					*addr = (FPW)0x00FF00FF; /* reset to read mode */
 					rcode = 1;
 					break;
 				}

 				/* show that we're waiting */
 			if ((now - last) > 1000) {	/* every second */
 					putc ('.');
 					last = now;
 				}
 			}

 			*addr = (FPW)0x00FF00FF;	/* reset to read mode */
 			printf (" done\n");
 		}
 	}
 	return rcode;
 }

 /*-----------------------------------------------------------------------
  * Copy memory to flash, returns:
  * 0 - OK
  * 1 - write timeout
  * 2 - Flash not erased
  * 4 - Flash not identified
  */

 int write_buff (flash_info_t *info, uchar *src, ulong addr, ulong cnt)
 {
 	ulong cp, wp;
 	FPW data;
 	int count, i, l, rc, port_width;

 	if (info->flash_id == FLASH_UNKNOWN) {
 		return 4;
 	}
 /* get lower word aligned address */
 #ifdef FLASH_PORT_WIDTH16
 	wp = (addr & ~1);
 	port_width = 2;
 #else
 	wp = (addr & ~3);
 	port_width = 4;
 #endif

 	/* save sernum if needed */
 	if (addr >= CONFIG_SYS_FLASH_SN_SECTOR && addr < CONFIG_SYS_FLASH_SN_BASE)
 	{
 		u_long dest = CONFIG_SYS_FLASH_SN_BASE;
 		u_short *sn = (u_short *)gd->bd->bi_sernum;

 		printf("(saving sernum)");
 		for (i=0; i<4; i++)
 		{
 			if ((rc = write_data(info, dest, sn[i])) != 0) {
 				return (rc);
 			}
 			dest += port_width;
 		}
 	}

 	/*
 	 * handle unaligned start bytes
 	 */
 	if ((l = addr - wp) != 0) {
 		data = 0;
 		for (i=0, cp=wp; i<l; ++i, ++cp) {
 			data = (data << 8) | (*(uchar *)cp);
 		}
 		for (; i<port_width && cnt>0; ++i) {
 			data = (data << 8) | *src++;
 			--cnt;
 			++cp;
 		}
 		for (; cnt==0 && i<port_width; ++i, ++cp) {
 			data = (data << 8) | (*(uchar *)cp);
 		}

 		if ((rc = write_data(info, wp, data)) != 0) {
 			return (rc);
 		}
 		wp += port_width;
 	}

 	/*
 	 * handle word aligned part
 	 */
 	count = 0;
 	while (cnt >= port_width) {
 		data = 0;
 		for (i=0; i<port_width; ++i) {
 			data = (data << 8) | *src++;
 		}
 		if ((rc = write_data(info, wp, data)) != 0) {
 			return (rc);
 		}
 		wp  += port_width;
 		cnt -= port_width;
 		if (count++ > 0x800)
 		{
 			putc('.');
 			count = 0;
 		}
 	}

 	if (cnt == 0) {
 		return (0);
 	}

 	/*
 	 * handle unaligned tail bytes
 	 */
 	data = 0;
 	for (i=0, cp=wp; i<port_width && cnt>0; ++i, ++cp) {
 		data = (data << 8) | *src++;
 		--cnt;
 	}
 	for (; i<port_width; ++i, ++cp) {
 		data = (data << 8) | (*(uchar *)cp);
 	}

 	return (write_data(info, wp, data));
 }

 /*-----------------------------------------------------------------------
  * Write a word or halfword to Flash, returns:
  * 0 - OK
  * 1 - write timeout
  * 2 - Flash not erased
  */
 static int write_data (flash_info_t *info, ulong dest, FPW data)
 {
 	FPWV *addr = (FPWV *)dest;
 	ulong status;
 	ulong start;
 	int flag;

 	/* Check if Flash is (sufficiently) erased */
 	if ((*addr & data) != data) {
 		printf("not erased at %08lx (%x)\n",(ulong)addr,*addr);
 		return (2);
 	}
 	/* Disable interrupts which might cause a timeout here */
 	flag = disable_interrupts();

 	*addr = (FPW)0x00400040;		/* write setup */
 	*addr = data;

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

 	start = get_timer (0);

 	while (((status = *addr) & (FPW)0x00800080) != (FPW)0x00800080) {
 		if (get_timer(start) > CONFIG_SYS_FLASH_WRITE_TOUT) {
 			*addr = (FPW)0x00FF00FF;	/* restore read mode */
 			return (1);
 		}
 	}

 	*addr = (FPW)0x00FF00FF;	/* restore read mode */

 	return (0);
 }
	/*
	* (C) Copyright 2001
	* Kyle Harris, Nexus Technologies, Inc. kharris@nexus-tech.net
	*
	* (C) Copyright 2001
	* Wolfgang Denk, DENX Software Engineering, wd@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 <mpc8xx.h>

	DECLARE_GLOBAL_DATA_PTR;

	flash_info_t flash_info[CONFIG_SYS_MAX_FLASH_BANKS]; /* info for FLASH chips */

	/*-----------------------------------------------------------------------
	* Protection Flags:
	*/
	#define FLAG_PROTECT_SET 0x01
	#define FLAG_PROTECT_CLEAR 0x02

	/* Board support for 1 or 2 flash devices */
	#undef FLASH_PORT_WIDTH32
	#define FLASH_PORT_WIDTH16

	#ifdef FLASH_PORT_WIDTH16
	#define FLASH_PORT_WIDTH ushort
	#define FLASH_PORT_WIDTHV vu_short
	#else
	#define FLASH_PORT_WIDTH ulong
	#define FLASH_PORT_WIDTHV vu_long
	#endif

	#define FPW FLASH_PORT_WIDTH
	#define FPWV FLASH_PORT_WIDTHV

	/*-----------------------------------------------------------------------
	* Functions
	*/
	static ulong flash_get_size (FPW addr, flash_info_t info);
	static int write_data (flash_info_t *info, ulong dest, FPW data);
	static void flash_get_offsets (ulong base, flash_info_t *info);

	/*-----------------------------------------------------------------------
	*/

	unsigned long flash_init (void)
	{
	volatile immap_t immap = (immap_t )CONFIG_SYS_IMMR;
	volatile memctl8xx_t *memctl = &immap->im_memctl;
	unsigned long size_b0;
	int i;

	/* Init: no FLASHes known */
	for (i=0; i<CONFIG_SYS_MAX_FLASH_BANKS; ++i) {
	flash_info[i].flash_id = FLASH_UNKNOWN;
	}

	/* Static FLASH Bank configuration here - FIXME XXX */
	size_b0 = flash_get_size((FPW *)FLASH_BASE0_PRELIM, &flash_info[0]);

	if (flash_info[0].flash_id == FLASH_UNKNOWN) {
	printf ("## Unknown FLASH on Bank 0 - Size = 0x%08lx = %ld MB\n",
	size_b0, size_b0<<20);
	}

	/* Remap FLASH according to real size */
	memctl->memc_or0 = CONFIG_SYS_OR_TIMING_FLASH \| (-size_b0 & 0xFFFF8000);
	memctl->memc_br0 = (CONFIG_SYS_FLASH_BASE & BR_BA_MSK) \| BR_PS_16 \| BR_MS_GPCM \| BR_V;

	/* Re-do sizing to get full correct info */
	size_b0 = flash_get_size((FPW *)CONFIG_SYS_FLASH_BASE, &flash_info[0]);

	flash_get_offsets (CONFIG_SYS_FLASH_BASE, &flash_info[0]);

	/* monitor protection ON by default */
	(void)flash_protect(FLAG_PROTECT_SET,
	CONFIG_SYS_FLASH_BASE,
	CONFIG_SYS_FLASH_BASE+monitor_flash_len-1,
	&flash_info[0]);

	flash_info[0].size = size_b0;

	return (size_b0);
	}

	/*-----------------------------------------------------------------------
	*/
	static void flash_get_offsets (ulong base, flash_info_t *info)
	{
	int i;

	if (info->flash_id == FLASH_UNKNOWN) {
	return;
	}

	if ((info->flash_id & FLASH_VENDMASK) == FLASH_MAN_INTEL) {
	for (i = 0; i < info->sector_count; i++) {
	info->start[i] = base + (i * 0x00020000);
	}
	}
	}

	/*-----------------------------------------------------------------------
	*/
	void flash_print_info (flash_info_t *info)
	{
	int i;

	if (info->flash_id == FLASH_UNKNOWN) {
	printf ("missing or unknown FLASH type\n");
	return;
	}

	switch (info->flash_id & FLASH_VENDMASK) {
	case FLASH_MAN_INTEL: printf ("INTEL "); break;
	default: printf ("Unknown Vendor "); break;
	}

	switch (info->flash_id & FLASH_TYPEMASK) {
	case FLASH_28F320J3A:
	printf ("28F320J3A\n"); break;
	case FLASH_28F640J3A:
	printf ("28F640J3A\n"); break;
	case FLASH_28F128J3A:
	printf ("28F128J3A\n"); break;
	default: printf ("Unknown Chip Type\n"); break;
	}

	printf (" Size: %ld MB in %d Sectors\n",
	info->size >> 20, info->sector_count);

	printf (" Sector Start Addresses:");
	for (i=0; i<info->sector_count; ++i) {
	if ((i % 5) == 0)
	printf ("\n ");
	printf (" %08lX%s",
	info->start[i],
	info->protect[i] ? " (RO)" : " "
	);
	}
	printf ("\n");
	return;
	}

	/*-----------------------------------------------------------------------
	*/


	/*-----------------------------------------------------------------------
	*/

	/*
	* The following code cannot be run from FLASH!
	*/

	static ulong flash_get_size (FPW addr, flash_info_t info)
	{
	FPW value;

	/* Write auto select command: read Manufacturer ID */
	addr[0x5555] = (FPW)0x00AA00AA;
	addr[0x2AAA] = (FPW)0x00550055;
	addr[0x5555] = (FPW)0x00900090;

	value = addr[0];

	switch (value) {
	case (FPW)INTEL_MANUFACT:
	info->flash_id = FLASH_MAN_INTEL;
	break;
	default:
	info->flash_id = FLASH_UNKNOWN;
	info->sector_count = 0;
	info->size = 0;
	addr[0] = (FPW)0x00FF00FF; /* restore read mode */
	return (0); /* no or unknown flash */
	}

	value = addr[1]; /* device ID */

	switch (value) {
	case (FPW)INTEL_ID_28F320J3A:
	info->flash_id += FLASH_28F320J3A;
	info->sector_count = 32;
	info->size = 0x00400000;
	break; /* => 4 MB */

	case (FPW)INTEL_ID_28F640J3A:
	info->flash_id += FLASH_28F640J3A;
	info->sector_count = 64;
	info->size = 0x00800000;
	break; /* => 8 MB */

	case (FPW)INTEL_ID_28F128J3A:
	info->flash_id += FLASH_28F128J3A;
	info->sector_count = 128;
	info->size = 0x01000000;
	break; /* => 16 MB */

	default:
	info->flash_id = FLASH_UNKNOWN;
	break;
	}

	if (info->sector_count > CONFIG_SYS_MAX_FLASH_SECT) {
	printf (" ERROR: sector count %d > max (%d) \n",
	info->sector_count, CONFIG_SYS_MAX_FLASH_SECT);
	info->sector_count = CONFIG_SYS_MAX_FLASH_SECT;
	}

	addr[0] = (FPW)0x00FF00FF; /* restore read mode */

	return (info->size);
	}


	/*-----------------------------------------------------------------------
	*/

	int flash_erase (flash_info_t *info, int s_first, int s_last)
	{
	int flag, prot, sect;
	ulong type, start, now, last;
	int rcode = 0;

	if ((s_first < 0) \|\| (s_first > s_last)) {
	if (info->flash_id == FLASH_UNKNOWN) {
	printf ("- missing\n");
	} else {
	printf ("- no sectors to erase\n");
	}
	return 1;
	}

	type = (info->flash_id & FLASH_VENDMASK);
	if ((type != FLASH_MAN_INTEL)) {
	printf ("Can't erase unknown flash type %08lx - aborted\n",
	info->flash_id);
	return 1;
	}

	prot = 0;
	for (sect=s_first; sect<=s_last; ++sect) {
	if (info->protect[sect]) {
	prot++;
	}
	}

	if (prot) {
	printf ("- Warning: %d protected sectors will not be erased!\n",
	prot);
	} else {
	printf ("\n");
	}

	start = get_timer (0);
	last = start;
	/* Start erase on unprotected sectors */
	for (sect = s_first; sect<=s_last; sect++) {
	if (info->protect[sect] == 0) { /* not protected */
	FPWV addr = (FPWV )(info->start[sect]);
	FPW status;

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

	addr = (FPW)0x00500050; / clear status register */
	addr = (FPW)0x00200020; / erase setup */
	addr = (FPW)0x00D000D0; / erase confirm */

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

	/* wait at least 80us - let's wait 1 ms */
	udelay (1000);

	while (((status = *addr) & (FPW)0x00800080) != (FPW)0x00800080) {
	if ((now=get_timer(start)) > CONFIG_SYS_FLASH_ERASE_TOUT) {
	printf ("Timeout\n");
	addr = (FPW)0x00B000B0; / suspend erase */
	addr = (FPW)0x00FF00FF; / reset to read mode */
	rcode = 1;
	break;
	}

	/* show that we're waiting */
	if ((now - last) > 1000) { /* every second */
	putc ('.');
	last = now;
	}
	}

	addr = (FPW)0x00FF00FF; / reset to read mode */
	printf (" done\n");
	}
	}
	return rcode;
	}

	/*-----------------------------------------------------------------------
	* Copy memory to flash, returns:
	* 0 - OK
	* 1 - write timeout
	* 2 - Flash not erased
	* 4 - Flash not identified
	*/

	int write_buff (flash_info_t info, uchar src, ulong addr, ulong cnt)
	{
	ulong cp, wp;
	FPW data;
	int count, i, l, rc, port_width;

	if (info->flash_id == FLASH_UNKNOWN) {
	return 4;
	}
	/* get lower word aligned address */
	#ifdef FLASH_PORT_WIDTH16
	wp = (addr & ~1);
	port_width = 2;
	#else
	wp = (addr & ~3);
	port_width = 4;
	#endif

	/* save sernum if needed */
	if (addr >= CONFIG_SYS_FLASH_SN_SECTOR && addr < CONFIG_SYS_FLASH_SN_BASE)
	{
	u_long dest = CONFIG_SYS_FLASH_SN_BASE;
	u_short sn = (u_short )gd->bd->bi_sernum;

	printf("(saving sernum)");
	for (i=0; i<4; i++)
	{
	if ((rc = write_data(info, dest, sn[i])) != 0) {
	return (rc);
	}
	dest += port_width;
	}
	}

	/*
	* handle unaligned start bytes
	*/
	if ((l = addr - wp) != 0) {
	data = 0;
	for (i=0, cp=wp; i<l; ++i, ++cp) {
	data = (data << 8) \| ((uchar )cp);
	}
	for (; i<port_width && cnt>0; ++i) {
	data = (data << 8) \| *src++;
	--cnt;
	++cp;
	}
	for (; cnt==0 && i<port_width; ++i, ++cp) {
	data = (data << 8) \| ((uchar )cp);
	}

	if ((rc = write_data(info, wp, data)) != 0) {
	return (rc);
	}
	wp += port_width;
	}

	/*
	* handle word aligned part
	*/
	count = 0;
	while (cnt >= port_width) {
	data = 0;
	for (i=0; i<port_width; ++i) {
	data = (data << 8) \| *src++;
	}
	if ((rc = write_data(info, wp, data)) != 0) {
	return (rc);
	}
	wp += port_width;
	cnt -= port_width;
	if (count++ > 0x800)
	{
	putc('.');
	count = 0;
	}
	}

	if (cnt == 0) {
	return (0);
	}

	/*
	* handle unaligned tail bytes
	*/
	data = 0;
	for (i=0, cp=wp; i<port_width && cnt>0; ++i, ++cp) {
	data = (data << 8) \| *src++;
	--cnt;
	}
	for (; i<port_width; ++i, ++cp) {
	data = (data << 8) \| ((uchar )cp);
	}

	return (write_data(info, wp, data));
	}

	/*-----------------------------------------------------------------------
	* Write a word or halfword to Flash, returns:
	* 0 - OK
	* 1 - write timeout
	* 2 - Flash not erased
	*/
	static int write_data (flash_info_t *info, ulong dest, FPW data)
	{
	FPWV addr = (FPWV )dest;
	ulong status;
	ulong start;
	int flag;

	/* Check if Flash is (sufficiently) erased */
	if ((*addr & data) != data) {
	printf("not erased at %08lx (%x)\n",(ulong)addr,*addr);
	return (2);
	}
	/* Disable interrupts which might cause a timeout here */
	flag = disable_interrupts();

	addr = (FPW)0x00400040; / write setup */
	*addr = data;

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

	start = get_timer (0);

	while (((status = *addr) & (FPW)0x00800080) != (FPW)0x00800080) {
	if (get_timer(start) > CONFIG_SYS_FLASH_WRITE_TOUT) {
	addr = (FPW)0x00FF00FF; / restore read mode */
	return (1);
	}
	}

	addr = (FPW)0x00FF00FF; / restore read mode */

	return (0);
	}