contrib/loaders/flash/pic32mx.s

   1 /***************************************************************************
   2  *   Copyright (C) 2010 by Spencer Oliver                                  *
   3  *   spen@spen-soft.co.uk                                                  *
   4  *                                                                         *
   5  *   This program is free software; you can redistribute it and/or modify  *
   6  *   it under the terms of the GNU General Public License as published by  *
   7  *   the Free Software Foundation; either version 2 of the License, or     *
   8  *   (at your option) any later version.                                   *
   9  *                                                                         *
  10  *   This program is distributed in the hope that it will be useful,       *
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  13  *   GNU General Public License for more details.                          *
  14  *                                                                         *
  15  *   You should have received a copy of the GNU General Public License     *
  16  *   along with this program; if not, write to the                         *
  17  *   Free Software Foundation, Inc.,                                       *
  18  *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.           *
  19  ***************************************************************************/
  20
  21         .text
  22         .arch m4k
  23         .set noreorder
  24         .set noat
  25
  26 /* params:
  27  * $a0 src adr - ram + result
  28  * $a1 dest adr - flash
  29  * $a2 count (32bit words)
  30  * vars
  31  *
  32  * temps:
  33  * $t0, $t1, $t2, $t3, $t4, $t5
  34  * $s0, $s1, $s3, $s4, $s5
  35  */
  36
  37         .type main, @function
  38         .global main
  39
  40 .ent main
  41 main:
  42         /* setup constants */
  43         lui             $t0, 0xaa99
  44         ori             $t0, 0x6655                             /* NVMKEY1 */
  45         lui             $t1, 0x5566
  46         ori             $t1, 0x99AA                             /* NVMKEY2 */
  47         lui             $t2, 0xBF80
  48         ori             $t2, 0xF400                             /* NVMCON */
  49         ori             $t3, $zero, 0x4003              /* NVMCON row write cmd */
  50         ori             $t4, $zero, 0x8000              /* NVMCON start cmd */
  51
  52 write_row:
  53         /* can we perform a row write: 128 32bit words */
  54         sltiu   $s3, $a2, 128
  55         bne             $s3, $zero, write_word
  56         ori             $t5, $zero, 0x4000              /* NVMCON clear cmd */
  57
  58         /* perform row write 512 bytes */
  59         sw              $a1, 32($t2)    /* set NVMADDR with dest addr - real addr */
  60         sw              $a0, 64($t2)    /* set NVMSRCADDR with src addr - real addr */
  61
  62         bal             progflash
  63         addiu   $a0, $a0, 512
  64         addiu   $a1, $a1, 512
  65         beq             $zero, $zero, write_row
  66         addiu   $a2, $a2, -128
  67
  68 write_word:
  69         /* write 32bit words */
  70         lui             $s5, 0xa000
  71         ori             $s5, 0x0000
  72         or              $a0, $a0, $s5                   /* convert to virtual addr */
  73
  74         beq             $zero, $zero, next_word
  75         ori             $t3, $zero, 0x4001              /* NVMCON word write cmd */
  76
  77 prog_word:
  78         lw              $s4, 0($a0)             /* load data - from virtual addr */
  79         sw              $s4, 48($t2)    /* set NVMDATA with data */
  80         sw              $a1, 32($t2)    /* set NVMADDR with dest addr - real addr */
  81
  82         bal             progflash
  83         addiu   $a0, $a0, 4
  84         addiu   $a1, $a1, 4
  85         addiu   $a2, $a2, -1
  86 next_word:
  87         bne             $a2, $zero, prog_word
  88         nop
  89
  90 done:
  91         beq             $zero, $zero, exit
  92         addiu   $a0, $zero, 0
  93
  94 error:
  95         /* save result to $a0 */
  96         addiu   $a0, $s1, 0
  97
  98 exit:
  99         sdbbp
 100 .end main
 101
 102         .type progflash, @function
 103         .global progflash
 104
 105 .ent progflash
 106 progflash:
 107         sw              $t3, 0($t2)             /* set NVMWREN */
 108         sw              $t0, 16($t2)    /* write NVMKEY1 */
 109         sw              $t1, 16($t2)    /* write NVMKEY2 */
 110         sw              $t4, 8($t2)             /* start operation */
 111
 112 waitflash:
 113         lw              $s0, 0($t2)
 114         and             $s0, $s0, $t4
 115         bne             $s0, $zero, waitflash
 116         nop
 117
 118         /* following is to comply with errata #34
 119          * 500ns delay required */
 120         nop
 121         nop
 122         nop
 123         nop
 124         /* check for errors */
 125         lw              $s1, 0($t2)
 126         andi    $s1, $zero, 0x3000
 127         bne             $s1, $zero, error
 128         sw              $t5, 4($t2)             /* clear NVMWREN */
 129         jr              $ra
 130         nop
 131
 132 .end progflash