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/***************************************************************************
* Copyright (C) 2010 by Spencer Oliver *
* spen@spen-soft.co.uk *
* *
* 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. *
***************************************************************************/
.text
.set noreorder
.set noat
/* params:
* $a0 src adr - ram + result
* $a1 dest adr - flash
* $a2 count (32bit words)
* vars
*
* temps:
* $t0, $t1, $t2, $t3, $t4, $t5
* $s0, $s1, $s3, $s4, $s5
*/
.type main, @function
.global main
.ent main
main:
/* setup constants */
lui $t0, 0xaa99
ori $t0, 0x6655 /* NVMKEY1 */
lui $t1, 0x5566
ori $t1, 0x99AA /* NVMKEY2 */
lui $t2, 0xBF80
ori $t2, 0xF400 /* NVMCON */
ori $t3, $zero, 0x4003 /* NVMCON row write cmd */
ori $t4, $zero, 0x8000 /* NVMCON start cmd */
write_row:
/* can we perform a row write: 128 32bit words */
sltiu $s3, $a2, 128
bne $s3, $zero, write_word
ori $t5, $zero, 0x4000 /* NVMCON clear cmd */
/* perform row write 512 bytes */
sw $a1, 32($t2) /* set NVMADDR with dest addr - real addr */
sw $a0, 64($t2) /* set NVMSRCADDR with src addr - real addr */
bal progflash
addiu $a0, $a0, 512
addiu $a1, $a1, 512
beq $zero, $zero, write_row
addiu $a2, $a2, -128
write_word:
/* write 32bit words */
lui $s5, 0xa000
ori $s5, 0x0000
or $a0, $a0, $s5 /* convert to virtual addr */
beq $zero, $zero, next_word
ori $t3, $zero, 0x4001 /* NVMCON word write cmd */
prog_word:
lw $s4, 0($a0) /* load data - from virtual addr */
sw $s4, 48($t2) /* set NVMDATA with data */
sw $a1, 32($t2) /* set NVMADDR with dest addr - real addr */
bal progflash
addiu $a0, $a0, 4
addiu $a1, $a1, 4
addiu $a2, $a2, -1
next_word:
bne $a2, $zero, prog_word
nop
done:
beq $zero, $zero, exit
addiu $a0, $zero, 0
error:
/* save result to $a0 */
addiu $a0, $s1, 0
exit:
sdbbp
.end main
.type progflash, @function
.global progflash
.ent progflash
progflash:
sw $t3, 0($t2) /* set NVMWREN */
sw $t0, 16($t2) /* write NVMKEY1 */
sw $t1, 16($t2) /* write NVMKEY2 */
sw $t4, 8($t2) /* start operation */
waitflash:
lw $s0, 0($t2)
and $s0, $s0, $t4
bne $s0, $zero, waitflash
nop
/* following is to comply with errata #34
* 500ns delay required */
nop
nop
nop
nop
/* check for errors */
lw $s1, 0($t2)
andi $s1, $zero, 0x3000
bne $s1, $zero, error
sw $t5, 4($t2) /* clear NVMWREN */
jr $ra
nop
.end progflash
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