contrib/loaders/flash/armv7m_cfi_span_16_dq7.s

   1 /***************************************************************************
   2  *   Copyright (C) 2005, 2007 by Dominic Rath                              *
   3  *   Dominic.Rath@gmx.de                                                   *
   4  *   Copyright (C) 2010 Spencer Oliver                                     *
   5  *   spen@spen-soft.co.uk                                                  *
   6  *                                                                         *
   7  *   This program is free software; you can redistribute it and/or modify  *
   8  *   it under the terms of the GNU General Public License as published by  *
   9  *   the Free Software Foundation; either version 2 of the License, or     *
  10  *   (at your option) any later version.                                   *
  11  *                                                                         *
  12  *   This program is distributed in the hope that it will be useful,       *
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  15  *   GNU General Public License for more details.                          *
  16  *                                                                         *
  17  *   You should have received a copy of the GNU General Public License     *
  18  *   along with this program; if not, write to the                         *
  19  *   Free Software Foundation, Inc.,                                       *
  20  *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.           *
  21  ***************************************************************************/
  22
  23         .text
  24         .syntax unified
  25         .arch armv7-m
  26         .thumb
  27         .thumb_func
  28
  29         .align 2
  30
  31 /* input parameters - */
  32 /*      R0 = source address */
  33 /*      R1 = destination address */
  34 /*      R2 = number of writes */
  35 /*      R3 = flash write command */
  36 /*      R4 = constant to mask DQ7 bits */
  37 /* output parameters - */
  38 /*      R5 = 0x80 ok 0x00 bad */
  39 /* temp registers - */
  40 /*      R6 = value read from flash to test status */
  41 /*      R7 = holding register */
  42 /* unlock registers - */
  43 /*  R8 = unlock1_addr */
  44 /*  R9 = unlock1_cmd */
  45 /*  R10 = unlock2_addr */
  46 /*  R11 = unlock2_cmd */
  47
  48 code:
  49         ldrh    r5, [r0], #2
  50         strh    r9, [r8]
  51         strh    r11, [r10]
  52         strh    r3, [r8]
  53         strh    r5, [r1]
  54         nop
  55 busy:
  56         ldrh    r6, [r1]
  57         eor             r7, r5, r6
  58         ands    r7, r4, r7
  59         bne             busy
  60         subs    r2, r2, #1      /* 0x1 */
  61         beq             success
  62         add             r1, r1, #2      /* 0x2 */
  63         b               code
  64
  65 success:
  66         mov             r5, #128        /* 0x80 */
  67         b               done
  68
  69 done:
  70         bkpt #0
  71
  72         .end