/*
   * (C) Copyright 2002
   * Brad Kemp, Seranoa Networks, Brad.Kemp@seranoa.com
   *
   * SPDX-License-Identifier:	GPL-2.0+
   */
  
  #include <common.h>
  #include <asm/processor.h>
  
  #undef  DEBUG_FLASH
  /*
   * This file implements a Common Flash Interface (CFI) driver for ppcboot.
   * 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.
   * It has been tested on an Intel Strataflash implementation.
   *
   * 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
   *
   * TODO
   * Use Primary Extended Query table (PRI) and Alternate Algorithm Query Table (ALT) to determine if protection is available
   * Add support for other command sets Use the PRI and ALT to determine command set
   * Verify erase and program timeouts.
   */
  
  #define FLASH_CMD_CFI			0x98
  #define FLASH_CMD_READ_ID		0x90
  #define FLASH_CMD_RESET			0xff
  #define FLASH_CMD_BLOCK_ERASE		0x20
  #define FLASH_CMD_ERASE_CONFIRM		0xD0
  #define FLASH_CMD_WRITE			0x40
  #define FLASH_CMD_PROTECT		0x60
  #define FLASH_CMD_PROTECT_SET		0x01
  #define FLASH_CMD_PROTECT_CLEAR		0xD0
  #define FLASH_CMD_CLEAR_STATUS		0x50
  #define FLASH_CMD_WRITE_TO_BUFFER       0xE8
  #define FLASH_CMD_WRITE_BUFFER_CONFIRM  0xD0
  
  #define FLASH_STATUS_DONE		0x80
  #define FLASH_STATUS_ESS		0x40
  #define FLASH_STATUS_ECLBS		0x20
  #define FLASH_STATUS_PSLBS		0x10
  #define FLASH_STATUS_VPENS		0x08
  #define FLASH_STATUS_PSS		0x04
  #define FLASH_STATUS_DPS		0x02
  #define FLASH_STATUS_R			0x01
  #define FLASH_STATUS_PROTECT		0x01
  
  #define FLASH_OFFSET_CFI		0x55
  #define FLASH_OFFSET_CFI_RESP		0x10
  #define FLASH_OFFSET_WTOUT		0x1F
  #define FLASH_OFFSET_WBTOUT             0x20
  #define FLASH_OFFSET_ETOUT		0x21
  #define FLASH_OFFSET_CETOUT             0x22
  #define FLASH_OFFSET_WMAX_TOUT		0x23
  #define FLASH_OFFSET_WBMAX_TOUT         0x24
  #define FLASH_OFFSET_EMAX_TOUT		0x25
  #define FLASH_OFFSET_CEMAX_TOUT         0x26
  #define FLASH_OFFSET_SIZE		0x27
  #define FLASH_OFFSET_INTERFACE          0x28
  #define FLASH_OFFSET_BUFFER_SIZE        0x2A
  #define FLASH_OFFSET_NUM_ERASE_REGIONS	0x2C
  #define FLASH_OFFSET_ERASE_REGIONS	0x2D
  #define FLASH_OFFSET_PROTECT		0x02
  #define FLASH_OFFSET_USER_PROTECTION    0x85
  #define FLASH_OFFSET_INTEL_PROTECTION   0x81
  
  
  #define FLASH_MAN_CFI			0x01000000
  
  
  typedef union {
  	unsigned char c;
  	unsigned short w;
  	unsigned long l;
  } cfiword_t;
  
  typedef union {
  	unsigned char * cp;
  	unsigned short *wp;
  	unsigned long *lp;
  } cfiptr_t;
  
  #define NUM_ERASE_REGIONS 4
  
  flash_info_t	flash_info[CONFIG_SYS_MAX_FLASH_BANKS]; /* info for FLASH chips	*/
  
  
  /*-----------------------------------------------------------------------
   * Functions
   */
  
  
  static void flash_add_byte(flash_info_t *info, cfiword_t * cword, uchar c);
  static void flash_make_cmd(flash_info_t * info, uchar cmd, void * cmdbuf);
  static void flash_write_cmd(flash_info_t * info, int sect, uchar offset, uchar cmd);
  static int flash_isequal(flash_info_t * info, int sect, uchar offset, uchar cmd);
  static int flash_isset(flash_info_t * info, int sect, uchar offset, uchar cmd);
  static int flash_detect_cfi(flash_info_t * info);
  static ulong flash_get_size (ulong base, int banknum);
  static int flash_write_cfiword (flash_info_t *info, ulong dest, cfiword_t cword);
  static int flash_full_status_check(flash_info_t * info, ulong sector, ulong tout, char * prompt);
  #ifdef CONFIG_SYS_FLASH_USE_BUFFER_WRITE
  static int flash_write_cfibuffer(flash_info_t * info, ulong dest, uchar * cp, int len);
  #endif
  /*-----------------------------------------------------------------------
   * create an address based on the offset and the port width
   */
  inline uchar * flash_make_addr(flash_info_t * info, int sect, int offset)
  {
  	return ((uchar *)(info->start[sect] + (offset * info->portwidth)));
  }
  /*-----------------------------------------------------------------------
   * read a character at a port width address
   */
  inline uchar flash_read_uchar(flash_info_t * info, uchar offset)
  {
  	uchar *cp;
  	cp = flash_make_addr(info, 0, offset);
  	return (cp[info->portwidth - 1]);
  }
  
  /*-----------------------------------------------------------------------
   * read a short word by swapping for ppc format.
   */
  ushort flash_read_ushort(flash_info_t * info, int sect,  uchar offset)
  {
      uchar * addr;
  
      addr = flash_make_addr(info, sect, offset);
      return ((addr[(2*info->portwidth) - 1] << 8) | addr[info->portwidth - 1]);
  
  }
  
  /*-----------------------------------------------------------------------
   * read a long word by picking the least significant byte of each maiximum
   * port size word. Swap for ppc format.
   */
  ulong flash_read_long(flash_info_t * info, int sect,  uchar offset)
  {
      uchar * addr;
  
      addr = flash_make_addr(info, sect, offset);
      return ( (addr[(2*info->portwidth) - 1] << 24 ) | (addr[(info->portwidth) -1] << 16) |
  	    (addr[(4*info->portwidth) - 1] << 8) | addr[(3*info->portwidth) - 1]);
  
  }
  
  /*-----------------------------------------------------------------------
   */
  unsigned long flash_init (void)
  {
  	unsigned long size;
  	int i;
  	unsigned long  address;
  
  
  	/* The flash is positioned back to back, with the demultiplexing of the chip
  	 * based on the A24 address line.
  	 *
  	 */
  
  	address = CONFIG_SYS_FLASH_BASE;
  	size = 0;
  
  	/* Init: no FLASHes known */
  	for (i=0; i<CONFIG_SYS_MAX_FLASH_BANKS; ++i) {
  		flash_info[i].flash_id = FLASH_UNKNOWN;
  		size += flash_info[i].size = flash_get_size(address, i);
  		address += CONFIG_SYS_FLASH_INCREMENT;
  		if (flash_info[0].flash_id == FLASH_UNKNOWN) {
  			printf ("## Unknown FLASH on Bank %d - Size = 0x%08lx = %ld MB
  ",i,
  				flash_info[0].size, flash_info[i].size<<20);
  		}
  	}
  
  #if 0 /* test-only */
  	/* Monitor protection ON by default */
  #if (CONFIG_SYS_MONITOR_BASE >= CONFIG_SYS_FLASH_BASE)
  	for(i=0; flash_info[0].start[i] < CONFIG_SYS_MONITOR_BASE+CONFIG_SYS_MONITOR_LEN-1; i++)
  		(void)flash_real_protect(&flash_info[0], i, 1);
  #endif
  #else
  	/* monitor protection ON by default */
  	flash_protect (FLAG_PROTECT_SET,
  		       - CONFIG_SYS_MONITOR_LEN,
  		       - 1, &flash_info[1]);
  #endif
  
  	return (size);
  }
  
  /*-----------------------------------------------------------------------
   */
  int flash_erase (flash_info_t *info, int s_first, int s_last)
  {
  	int rcode = 0;
  	int prot;
  	int sect;
  
  	if( info->flash_id != FLASH_MAN_CFI) {
  		printf ("Can't erase unknown flash type - aborted
  ");
  		return 1;
  	}
  	if ((s_first < 0) || (s_first > s_last)) {
  		printf ("- no sectors to erase
  ");
  		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!
  ",
  			prot);
  	} else {
  		printf ("
  ");
  	}
  
  
  	for (sect = s_first; sect<=s_last; sect++) {
  		if (info->protect[sect] == 0) { /* not protected */
  			flash_write_cmd(info, sect, 0, FLASH_CMD_CLEAR_STATUS);
  			flash_write_cmd(info, sect, 0, FLASH_CMD_BLOCK_ERASE);
  			flash_write_cmd(info, sect, 0, FLASH_CMD_ERASE_CONFIRM);
  
  			if(flash_full_status_check(info, sect, info->erase_blk_tout, "erase")) {
  				rcode = 1;
  			} else
  				printf(".");
  		}
  	}
  	printf (" done
  ");
  	return rcode;
  }
  
  /*-----------------------------------------------------------------------
   */
  void flash_print_info  (flash_info_t *info)
  {
  	int i;
  
  	if (info->flash_id != FLASH_MAN_CFI) {
  		printf ("missing or unknown FLASH type
  ");
  		return;
  	}
  
  	printf("CFI conformant FLASH (%d x %d)",
  	       (info->portwidth	 << 3 ), (info->chipwidth  << 3 ));
  	printf ("  Size: %ld MB in %d Sectors
  ",
  		info->size >> 20, info->sector_count);
  	printf(" Erase timeout %ld ms, write timeout %ld ms, buffer write timeout %ld ms, buffer size %d
  ",
  	       info->erase_blk_tout, info->write_tout, info->buffer_write_tout, info->buffer_size);
  
  	printf ("  Sector Start Addresses:");
  	for (i=0; i<info->sector_count; ++i) {
  #ifdef CONFIG_SYS_FLASH_EMPTY_INFO
  		int k;
  		int size;
  		int erased;
  		volatile unsigned long *flash;
  
  		/*
  		 * Check if whole sector is erased
  		 */
  		if (i != (info->sector_count-1))
  		  size = info->start[i+1] - info->start[i];
  		else
  		  size = info->start[0] + info->size - info->start[i];
  		erased = 1;
  		flash = (volatile unsigned long *)info->start[i];
  		size = size >> 2;        /* divide by 4 for longword access */
  		for (k=0; k<size; k++)
  		  {
  		    if (*flash++ != 0xffffffff)
  		      {
  			erased = 0;
  			break;
  		      }
  		  }
  
  		if ((i % 5) == 0)
  			printf ("
     ");
  		/* print empty and read-only info */
  		printf (" %08lX%s%s",
  			info->start[i],
  			erased ? " E" : "  ",
  			info->protect[i] ? "RO " : "   ");
  #else
  		if ((i % 5) == 0)
  			printf ("
     ");
  		printf (" %08lX%s",
  			info->start[i],
  			info->protect[i] ? " (RO)" : "     ");
  #endif
  	}
  	printf ("
  ");
  	return;
  }
  
  /*-----------------------------------------------------------------------
   * Copy memory to flash, returns:
   * 0 - OK
   * 1 - write timeout
   * 2 - Flash not erased
   */
  int write_buff (flash_info_t *info, uchar *src, ulong addr, ulong cnt)
  {
  	ulong wp;
  	ulong cp;
  	int aln;
  	cfiword_t cword;
  	int i, rc;
  
  	/* get lower aligned address */
  	wp = (addr & ~(info->portwidth - 1));
  
  	/* handle unaligned start */
  	if((aln = addr - wp) != 0) {
  		cword.l = 0;
  		cp = wp;
  		for(i=0;i<aln; ++i, ++cp)
  			flash_add_byte(info, &cword, (*(uchar *)cp));
  
  		for(; (i< info->portwidth) && (cnt > 0) ; i++) {
  			flash_add_byte(info, &cword, *src++);
  			cnt--;
  			cp++;
  		}
  		for(; (cnt == 0) && (i < info->portwidth); ++i, ++cp)
  			flash_add_byte(info, &cword, (*(uchar *)cp));
  		if((rc = flash_write_cfiword(info, wp, cword)) != 0)
  			return rc;
  		wp = cp;
  	}
  
  #ifdef CONFIG_SYS_FLASH_USE_BUFFER_WRITE
  	while(cnt >= info->portwidth) {
  		i = info->buffer_size > cnt? cnt: info->buffer_size;
  		if((rc = flash_write_cfibuffer(info, wp, src,i)) != ERR_OK)
  			return rc;
  		wp += i;
  		src += i;
  		cnt -=i;
  	}
  #else
  	/* handle the aligned part */
  	while(cnt >= info->portwidth) {
  		cword.l = 0;
  		for(i = 0; i < info->portwidth; i++) {
  			flash_add_byte(info, &cword, *src++);
  		}
  		if((rc = flash_write_cfiword(info, wp, cword)) != 0)
  			return rc;
  		wp += info->portwidth;
  		cnt -= info->portwidth;
  	}
  #endif /* CONFIG_SYS_FLASH_USE_BUFFER_WRITE */
  	if (cnt == 0) {
  		return (0);
  	}
  
  	/*
  	 * handle unaligned tail bytes
  	 */
  	cword.l = 0;
  	for (i=0, cp=wp; (i<info->portwidth) && (cnt>0); ++i, ++cp) {
  		flash_add_byte(info, &cword, *src++);
  		--cnt;
  	}
  	for (; i<info->portwidth; ++i, ++cp) {
  		flash_add_byte(info, & cword, (*(uchar *)cp));
  	}
  
  	return flash_write_cfiword(info, wp, cword);
  }
  
  /*-----------------------------------------------------------------------
   */
  int flash_real_protect(flash_info_t *info, long sector, int prot)
  {
  	int retcode = 0;
  
  	flash_write_cmd(info, sector, 0, FLASH_CMD_CLEAR_STATUS);
  	flash_write_cmd(info, sector, 0, FLASH_CMD_PROTECT);
  	if(prot)
  		flash_write_cmd(info, sector, 0, FLASH_CMD_PROTECT_SET);
  	else
  		flash_write_cmd(info, sector, 0, FLASH_CMD_PROTECT_CLEAR);
  
  	if((retcode = flash_full_status_check(info, sector, info->erase_blk_tout,
  					 prot?"protect":"unprotect")) == 0) {
  
  		info->protect[sector] = prot;
  		/* Intel's unprotect unprotects all locking */
  		if(prot == 0) {
  			int i;
  			for(i = 0 ; i<info->sector_count; i++) {
  				if(info->protect[i])
  					flash_real_protect(info, i, 1);
  			}
  		}
  	}
  
  	return retcode;
  }
  /*-----------------------------------------------------------------------
   *  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, ulong sector, ulong tout, char * prompt)
  {
  	ulong start;
  
  	/* Wait for command completion */
  	start = get_timer (0);
  	while(!flash_isset(info, sector, 0, FLASH_STATUS_DONE)) {
  		if (get_timer(start) > info->erase_blk_tout) {
  			printf("Flash %s timeout at address %lx
  ", prompt, info->start[sector]);
  			flash_write_cmd(info, sector, 0, FLASH_CMD_RESET);
  			return ERR_TIMOUT;
  		}
  	}
  	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, ulong sector, ulong tout, char * prompt)
  {
  	int retcode;
  	retcode = flash_status_check(info, sector, tout, prompt);
  	if((retcode == ERR_OK) && !flash_isequal(info,sector, 0, FLASH_STATUS_DONE)) {
  		retcode = ERR_INVAL;
  		printf("Flash %s error at address %lx
  ", prompt,info->start[sector]);
  		if(flash_isset(info, sector, 0, FLASH_STATUS_ECLBS | FLASH_STATUS_PSLBS)){
  			printf("Command Sequence Error.
  ");
  		} else if(flash_isset(info, sector, 0, FLASH_STATUS_ECLBS)){
  			printf("Block Erase Error.
  ");
  			retcode = ERR_NOT_ERASED;
  		} else if (flash_isset(info, sector, 0, FLASH_STATUS_PSLBS)) {
  			printf("Locking Error
  ");
  		}
  		if(flash_isset(info, sector, 0, FLASH_STATUS_DPS)){
  			printf("Block locked.
  ");
  			retcode = ERR_PROTECTED;
  		}
  		if(flash_isset(info, sector, 0, FLASH_STATUS_VPENS))
  			printf("Vpp Low Error.
  ");
  	}
  	flash_write_cmd(info, sector, 0, FLASH_CMD_RESET);
  	return retcode;
  }
  /*-----------------------------------------------------------------------
   */
  static void flash_add_byte(flash_info_t *info, cfiword_t * cword, uchar c)
  {
  	switch(info->portwidth) {
  	case FLASH_CFI_8BIT:
  		cword->c = c;
  		break;
  	case FLASH_CFI_16BIT:
  		cword->w = (cword->w << 8) | c;
  		break;
  	case FLASH_CFI_32BIT:
  		cword->l = (cword->l << 8) | c;
  	}
  }
  
  
  /*-----------------------------------------------------------------------
   * make a proper sized command based on the port and chip widths
   */
  static void flash_make_cmd(flash_info_t * info, uchar cmd, void * cmdbuf)
  {
  	int i;
  	uchar *cp = (uchar *)cmdbuf;
  	for(i=0; i< info->portwidth; i++)
  		*cp++ = ((i+1) % info->chipwidth) ? '\0':cmd;
  }
  
  /*
   * Write a proper sized command to the correct address
   */
  static void flash_write_cmd(flash_info_t * info, int sect, uchar offset, uchar cmd)
  {
  
  	volatile cfiptr_t addr;
  	cfiword_t cword;
  	addr.cp = flash_make_addr(info, sect, offset);
  	flash_make_cmd(info, cmd, &cword);
  	switch(info->portwidth) {
  	case FLASH_CFI_8BIT:
  		*addr.cp = cword.c;
  		break;
  	case FLASH_CFI_16BIT:
  		*addr.wp = cword.w;
  		break;
  	case FLASH_CFI_32BIT:
  		*addr.lp = cword.l;
  		break;
  	}
  }
  
  /*-----------------------------------------------------------------------
   */
  static int flash_isequal(flash_info_t * info, int sect, uchar offset, uchar cmd)
  {
  	cfiptr_t cptr;
  	cfiword_t cword;
  	int retval;
  	cptr.cp = flash_make_addr(info, sect, offset);
  	flash_make_cmd(info, cmd, &cword);
  	switch(info->portwidth) {
  	case FLASH_CFI_8BIT:
  		retval = (cptr.cp[0] == cword.c);
  		break;
  	case FLASH_CFI_16BIT:
  		retval = (cptr.wp[0] == cword.w);
  		break;
  	case FLASH_CFI_32BIT:
  		retval = (cptr.lp[0] == cword.l);
  		break;
  	default:
  		retval = 0;
  		break;
  	}
  	return retval;
  }
  /*-----------------------------------------------------------------------
   */
  static int flash_isset(flash_info_t * info, int sect, uchar offset, uchar cmd)
  {
  	cfiptr_t cptr;
  	cfiword_t cword;
  	int retval;
  	cptr.cp = flash_make_addr(info, sect, offset);
  	flash_make_cmd(info, cmd, &cword);
  	switch(info->portwidth) {
  	case FLASH_CFI_8BIT:
  		retval = ((cptr.cp[0] & cword.c) == cword.c);
  		break;
  	case FLASH_CFI_16BIT:
  		retval = ((cptr.wp[0] & cword.w) == cword.w);
  		break;
  	case FLASH_CFI_32BIT:
  		retval = ((cptr.lp[0] & cword.l) == cword.l);
  		break;
  	default:
  		retval = 0;
  		break;
  	}
  	return retval;
  }
  
  /*-----------------------------------------------------------------------
   * detect if flash is compatible with the Common Flash Interface (CFI)
   * http://www.jedec.org/download/search/jesd68.pdf
   *
  */
  static int flash_detect_cfi(flash_info_t * info)
  {
  
  	for(info->portwidth=FLASH_CFI_8BIT; info->portwidth <= FLASH_CFI_32BIT;
  	    info->portwidth <<= 1) {
  		for(info->chipwidth =FLASH_CFI_BY8;
  		    info->chipwidth <= info->portwidth;
  		    info->chipwidth <<= 1) {
  			flash_write_cmd(info, 0, 0, FLASH_CMD_RESET);
  			flash_write_cmd(info, 0, FLASH_OFFSET_CFI, FLASH_CMD_CFI);
  			if(flash_isequal(info, 0, FLASH_OFFSET_CFI_RESP,'Q') &&
  			   flash_isequal(info, 0, FLASH_OFFSET_CFI_RESP + 1, 'R') &&
  			   flash_isequal(info, 0, FLASH_OFFSET_CFI_RESP + 2, 'Y'))
  				return 1;
  		}
  	}
  	return 0;
  }
  /*
   * The following code cannot be run from FLASH!
   *
   */
  static ulong flash_get_size (ulong base, int banknum)
  {
  	flash_info_t * info = &flash_info[banknum];
  	int i, j;
  	int sect_cnt;
  	unsigned long sector;
  	unsigned long tmp;
  	int size_ratio;
  	uchar num_erase_regions;
  	int  erase_region_size;
  	int  erase_region_count;
  
  	info->start[0] = base;
  
  	if(flash_detect_cfi(info)){
  #ifdef DEBUG_FLASH
  		printf("portwidth=%d chipwidth=%d
  ", info->portwidth, info->chipwidth); /* test-only */
  #endif
  		size_ratio = info->portwidth / info->chipwidth;
  		num_erase_regions = flash_read_uchar(info, FLASH_OFFSET_NUM_ERASE_REGIONS);
  #ifdef DEBUG_FLASH
  		printf("found %d erase regions
  ", num_erase_regions);
  #endif
  		sect_cnt = 0;
  		sector = base;
  		for(i = 0 ; i < num_erase_regions; i++) {
  			if(i > NUM_ERASE_REGIONS) {
  				printf("%d erase regions found, only %d used
  ",
  				       num_erase_regions, NUM_ERASE_REGIONS);
  				break;
  			}
  			tmp = flash_read_long(info, 0, FLASH_OFFSET_ERASE_REGIONS);
  			erase_region_size = (tmp & 0xffff)? ((tmp & 0xffff) * 256): 128;
  			tmp >>= 16;
  			erase_region_count = (tmp & 0xffff) +1;
  			for(j = 0; j< erase_region_count; j++) {
  				info->start[sect_cnt] = sector;
  				sector += (erase_region_size * size_ratio);
  				info->protect[sect_cnt] = flash_isset(info, sect_cnt, FLASH_OFFSET_PROTECT, FLASH_STATUS_PROTECT);
  				sect_cnt++;
  			}
  		}
  
  		info->sector_count = sect_cnt;
  		/* multiply the size by the number of chips */
  		info->size = (1 << flash_read_uchar(info, FLASH_OFFSET_SIZE)) * size_ratio;
  		info->buffer_size = (1 << flash_read_ushort(info, 0, FLASH_OFFSET_BUFFER_SIZE));
  		tmp = 1 << flash_read_uchar(info, FLASH_OFFSET_ETOUT);
  		info->erase_blk_tout = (tmp * (1 << flash_read_uchar(info, FLASH_OFFSET_EMAX_TOUT)));
  		tmp = 1 << flash_read_uchar(info, FLASH_OFFSET_WBTOUT);
  		info->buffer_write_tout = (tmp * (1 << flash_read_uchar(info, FLASH_OFFSET_WBMAX_TOUT)));
  		tmp = 1 << flash_read_uchar(info, FLASH_OFFSET_WTOUT);
  		info->write_tout = (tmp * (1 << flash_read_uchar(info, FLASH_OFFSET_WMAX_TOUT)))/ 1000;
  		info->flash_id = FLASH_MAN_CFI;
  	}
  
  	flash_write_cmd(info, 0, 0, FLASH_CMD_RESET);
  	return(info->size);
  }
  
  
  /*-----------------------------------------------------------------------
   */
  static int flash_write_cfiword (flash_info_t *info, ulong dest, cfiword_t cword)
  {
  
  	cfiptr_t cptr;
  	int flag;
  
  	cptr.cp = (uchar *)dest;
  
  	/* Check if Flash is (sufficiently) erased */
  	switch(info->portwidth) {
  	case FLASH_CFI_8BIT:
  		flag = ((cptr.cp[0] & cword.c) == cword.c);
  		break;
  	case FLASH_CFI_16BIT:
  		flag = ((cptr.wp[0] & cword.w) == cword.w);
  		break;
  	case FLASH_CFI_32BIT:
  		flag = ((cptr.lp[0] & cword.l)	== cword.l);
  		break;
  	default:
  		return 2;
  	}
  	if(!flag)
  		return 2;
  
  	/* Disable interrupts which might cause a timeout here */
  	flag = disable_interrupts();
  
  	flash_write_cmd(info, 0, 0, FLASH_CMD_CLEAR_STATUS);
  	flash_write_cmd(info, 0, 0, FLASH_CMD_WRITE);
  
  	switch(info->portwidth) {
  	case FLASH_CFI_8BIT:
  		cptr.cp[0] = cword.c;
  		break;
  	case FLASH_CFI_16BIT:
  		cptr.wp[0] = cword.w;
  		break;
  	case FLASH_CFI_32BIT:
  		cptr.lp[0] = cword.l;
  		break;
  	}
  
  	/* re-enable interrupts if necessary */
  	if(flag)
  		enable_interrupts();
  
  	return flash_full_status_check(info, 0, info->write_tout, "write");
  }
  
  #ifdef CONFIG_SYS_FLASH_USE_BUFFER_WRITE
  
  /* loop through the sectors from the highest address
   * when the passed address is greater or equal to the sector address
   * we have a match
   */
  static int find_sector(flash_info_t *info, ulong addr)
  {
  	int sector;
  	for(sector = info->sector_count - 1; sector >= 0; sector--) {
  		if(addr >= info->start[sector])
  			break;
  	}
  	return sector;
  }
  
  static int flash_write_cfibuffer(flash_info_t * info, ulong dest, uchar * cp, int len)
  {
  
  	int sector;
  	int cnt;
  	int retcode;
  	volatile cfiptr_t src;
  	volatile cfiptr_t dst;
  
  	src.cp = cp;
  	dst.cp = (uchar *)dest;
  	sector = find_sector(info, dest);
  	flash_write_cmd(info, sector, 0, FLASH_CMD_CLEAR_STATUS);
  	flash_write_cmd(info, sector, 0, FLASH_CMD_WRITE_TO_BUFFER);
  	if((retcode = flash_status_check(info, sector, info->buffer_write_tout,
  					 "write to buffer")) == ERR_OK) {
  		switch(info->portwidth) {
  		case FLASH_CFI_8BIT:
  			cnt = len;
  			break;
  		case FLASH_CFI_16BIT:
  			cnt = len >> 1;
  			break;
  		case FLASH_CFI_32BIT:
  			cnt = len >> 2;
  			break;
  		default:
  			return ERR_INVAL;
  			break;
  		}
  		flash_write_cmd(info, sector, 0, (uchar)cnt-1);
  		while(cnt-- > 0) {
  			switch(info->portwidth) {
  			case FLASH_CFI_8BIT:
  				*dst.cp++ = *src.cp++;
  				break;
  			case FLASH_CFI_16BIT:
  				*dst.wp++ = *src.wp++;
  				break;
  			case FLASH_CFI_32BIT:
  				*dst.lp++ = *src.lp++;
  				break;
  			default:
  				return ERR_INVAL;
  				break;
  			}
  		}
  		flash_write_cmd(info, sector, 0, FLASH_CMD_WRITE_BUFFER_CONFIRM);
  		retcode = flash_full_status_check(info, sector, info->buffer_write_tout,
  					     "buffer write");
  	}
  	flash_write_cmd(info, sector, 0, FLASH_CMD_CLEAR_STATUS);
  	return retcode;
  }
  #endif /* CONFIG_SYS_USE_FLASH_BUFFER_WRITE */