contrib/loaders/flash/stellaris.s

   1 /***************************************************************************
   2  *   Copyright (C) 2006 by Magnus Lundin                                   *
   3  *   lundin@mlu.mine.nu                                                    *
   4  *                                                                         *
   5  *   Copyright (C) 2008 by Spencer Oliver                                  *
   6  *   spen@spen-soft.co.uk                                                  *
   7  *                                                                         *
   8  *   This program is free software; you can redistribute it and/or modify  *
   9  *   it under the terms of the GNU General Public License as published by  *
  10  *   the Free Software Foundation; either version 2 of the License, or     *
  11  *   (at your option) any later version.                                   *
  12  *                                                                         *
  13  *   This program is distributed in the hope that it will be useful,       *
  14  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  15  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  16  *   GNU General Public License for more details.                          *
  17  *                                                                         *
  18  *   You should have received a copy of the GNU General Public License     *
  19  *   along with this program; if not, write to the                         *
  20  *   Free Software Foundation, Inc.,                                       *
  21  *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.           *
  22  ***************************************************************************/
  23
  24         .text
  25         .syntax unified
  26         .cpu cortex-m3
  27         .thumb
  28         .thumb_func
  29
  30 /*
  31  * Params :
  32  * r0 = workarea start
  33  * r1 = workarea end
  34  * r2 = target address
  35  * r3 = count (32bit words)
  36  *
  37  * Clobbered:
  38  * r4 = pFLASH_CTRL_BASE
  39  * r5 = FLASHWRITECMD
  40  * r7 - rp
  41  * r8 - wp, tmp
  42  */
  43
  44 write:
  45         ldr     r4, pFLASH_CTRL_BASE
  46         ldr     r5, FLASHWRITECMD
  47
  48 wait_fifo:
  49         ldr     r8, [r0, #0]    /* read wp */
  50         cmp     r8, #0                  /* abort if wp == 0 */
  51         beq     exit
  52         ldr     r7, [r0, #4]    /* read rp */
  53         cmp     r7, r8                  /* wait until rp != wp */
  54         beq     wait_fifo
  55
  56 mainloop:
  57         str             r2, [r4, #0]    /* FMA - write address */
  58         add             r2, r2, #4              /* increment target address */
  59         ldr             r8, [r7], #4
  60         str             r8, [r4, #4]    /* FMD - write data */
  61         str             r5, [r4, #8]    /* FMC - enable write */
  62 busy:
  63         ldr             r8, [r4, #8]
  64         tst             r8, #1
  65         bne             busy
  66
  67         cmp     r7, r1                  /* wrap rp at end of buffer */
  68         it      cs
  69         addcs   r7, r0, #8              /* skip loader args */
  70         str     r7, [r0, #4]    /* store rp */
  71         subs    r3, r3, #1              /* decrement word count */
  72         cbz     r3, exit                /* loop if not done */
  73         b               wait_fifo
  74 exit:
  75         bkpt    #0
  76
  77 pFLASH_CTRL_BASE: .word 0x400FD000
  78 FLASHWRITECMD: .word 0xA4420001