[U-Boot-Users] AMD Mirror Bit Write Buffer Programing algorythm troubles

[Conn Clark <clark@esteem.com>]

Hello all,

	I'm having troubles with an AMD Mirror Bit Write Buffer Programing 
algorythm I have written for U-Boot. I'm hoping that someone can provide 
some insight to the problem. We are using an Am29LV320MB part and 
according to the data sheet I am doing everything correctly (at least I 
think I am ). So if someone could confirm my code is valid or wrong I 
would appreciate it.

	I am having troubles with the flash part decraring it has timed out. It 
does complete the first buffer programing sequence and all programed 
data is valid. If I force it to continue only the first buffer write to 
each sector is programed.

	My problems may be due to a bad chip. This is a prototype and we had 
some issues with the power supply that may have dammaged the chip. I 
doubt this because our Jtag debugger programs this part in write buffer 
mode just fine.

Below is the two functions of intrest and I have attached the full 
flash.c file.

/************* Begin code *****************/

#ifdef  WRITE_BUFFER_PROG
int write_buffer_program(flash_info_t *info, ulong dest, char *src);
#endif

/*-----------------------------------------------------------------------
  * 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 cp, wp, data;
	int i, l, rc;

	wp = (addr & ~3);	/* get lower word aligned address */

	/*
	 * 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<4 && cnt>0; ++i) {
			data = (data << 8) | *src++;
			--cnt;
			++cp;
		}
		for (; cnt==0 && i<4; ++i, ++cp) {
			data = (data << 8) | (*(uchar *)cp);
		}

		if ((rc = write_word(info, wp, data)) != 0) {
			return (rc);
		}
		wp += 4;
	}

	/*
	 * handle word aligned part
	 */
	while (cnt >= 4) {
#ifdef  WRITE_BUFFER_PROG
	  if((cnt>=32)& !(wp & 0x1F)) {    /* if destination is aligned on 32 
byte boundry use write burst */
		if ((rc = write_buffer_program(info,wp,src)) != 0) {
			return (rc);
		}
		wp  += 32;
		src += 32;
		cnt -= 32;
           } else
#endif
           {
		data = 0;
		for (i=0; i<4; ++i) {
			data = (data << 8) | *src++;
		}
		if ((rc = write_word(info, wp, data)) != 0) {
			return (rc);
		}
		wp  += 4;
		cnt -= 4;
	  }
	}

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

	/*
	 * handle unaligned tail bytes
	 */
	data = 0;
	for (i=0, cp=wp; i<4 && cnt>0; ++i, ++cp) {
		data = (data << 8) | *src++;
		--cnt;
	}
	for (; i<4; ++i, ++cp) {
		data = (data << 8) | (*(uchar *)cp);
	}

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


#ifdef  WRITE_BUFFER_PROG
/*-----------------------------------------------------------------------
  * Write a bunch of word to Flash, returns:
  * 0 - OK
  * 1 - write timeout
  * 2 - Flash not erased
  * 3 - write buffer abort
  */
int write_buffer_program(flash_info_t *info, ulong dest, char *src)
{
	volatile CFG_FLASH_WORD_SIZE *target_sector;
	volatile CFG_FLASH_WORD_SIZE *addr2 = (CFG_FLASH_WORD_SIZE 
*)(info->start[0]);
	volatile CFG_FLASH_WORD_SIZE *dest2 = (CFG_FLASH_WORD_SIZE *)dest;
	volatile CFG_FLASH_WORD_SIZE *data2 = (CFG_FLASH_WORD_SIZE *)src;
CFG_FLASH_WORD_SIZE progstat;
         ulong start;
	int flag;
	int i,j;
	j=info->sector_count -1;
	/*find sector start address to program*/
	while(info->start[j] > dest) j--;

	target_sector = (CFG_FLASH_WORD_SIZE *)(info->start[j]);
	/* Check if Flash is (sufficiently) erased */
/*	if ((*dest2 & *data2) != *data2) {
		return (2);
	} */

         /* Disable interrupts which might cause a timeout here */
	flag = disable_interrupts();
	addr2[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00AA00AA;
	addr2[CFG_FLASH_ADDR1] = (CFG_FLASH_WORD_SIZE)0x00550055;
	target_sector[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00250025; /* 
write to buffer command */
	/*write count of words to buffer minus 1 */
	target_sector[CFG_FLASH_ADDR0] = (32/sizeof(CFG_FLASH_WORD_SIZE)) - 1 ;
	/*write first word */
/*	dest2[0] = data2[0]; */
         /* write the rest */
         i=0;
	do
	  {
	    dest2[i] = data2[i];
             i++;
	  }while(i<(32/sizeof(CFG_FLASH_WORD_SIZE)));
	/*write buffer command */
	target_sector[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00290029;
	    /* re-enable interrupts if necessary */
             if (flag)
	      enable_interrupts();
	    /* data polling for D7 */
            i--;  /* decrement index to point to last word written */
	    start = get_timer (0);

	    while( ((progstat=dest2[i]) & (CFG_FLASH_WORD_SIZE)0x00800080) !=
		/*check for chip time out or abort*/
		   (data2[i] & (CFG_FLASH_WORD_SIZE)0x00800080) ){
               if(progstat & (CFG_FLASH_WORD_SIZE)0x00220022) {
		if(progstat & (CFG_FLASH_WORD_SIZE)0x00200020){   /*check for chip 
time out*/
		/* return success if it really did work */
		    if( (dest2[i] & (CFG_FLASH_WORD_SIZE)0x00800080) ==
			   (data2[i] & (CFG_FLASH_WORD_SIZE)0x00800080) ) return 0;
                     data2[i] = (CFG_FLASH_WORD_SIZE)0x00F000F0;   /* 
reset flash chip */
printf("TimeOut\n"); /* for debugging only, remove */
                     return 1;
                    }
		/* return success if it really did work */
		if( (dest2[i] & (CFG_FLASH_WORD_SIZE)0x00800080) ==
		   (data2[i] & (CFG_FLASH_WORD_SIZE)0x00800080) ) return 0;
		/* if your here it is an abort condition */
		addr2[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00AA00AA;
		addr2[CFG_FLASH_ADDR1] = (CFG_FLASH_WORD_SIZE)0x00550055;
		addr2[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00F000F0;  /* Write 
buffer abort reset */
printf("abort\n");  /* for debugging only, remove */
		return 3;
                 }
	      if (get_timer(start) > CFG_FLASH_WRITE_TOUT) {
		return (1);    /* U-Boot timer time out */
	      }
	    }
  return (0);

}

#endif /*  WRITE_BUFFER_PROG   */


/*********** End code *********/


Thanks

	Conn Clark
-- 

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*****************************************************************

Conn Clark
Engineering Stooge				clark at esteem.com
Electronic Systems Technology Inc.		www.esteem.com

Stock Ticker Symbol				ELST

"clark at esteem.com" Copyright 2000 By Electronic Systems Technology
  This email address may be used to communicate to Conn Clark
  provided it is not being used for advertisement purposes, unless
  prior written consent is given. This email address may not be
  sold under any circumstances. All other rights reserved.
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