contrib/loaders/flash/max32xxx/max32xxx.s

   1 /***************************************************************************
   2  *   Copyright (C) 2016 by Maxim Integrated                                *
   3  *   Kevin Gillespie <kevin.gillespie@maximintegrated.com                  *
   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, see <http://www.gnu.org/licenses/>. *
  17  ***************************************************************************/
  18
  19 .text
  20 .syntax unified
  21 .cpu cortex-m3
  22 .thumb
  23 .thumb_func
  24
  25 /*
  26  * Params :
  27  * r0 = workarea start
  28  * r1 = workarea end
  29  * r2 = target address
  30  * r3 = count (32bit words)
  31  * r4 = pFLASH_CTRL_BASE
  32  *
  33  * Clobbered:
  34  * r5 = FLASHWRITECMD
  35  * r7 - rp
  36  * r8 - wp, tmp
  37  */
  38
  39 write:
  40
  41 wait_fifo:
  42 ldr     r8, [r0, #0]    /* read wp */
  43 cmp     r8, #0                  /* abort if wp == 0 */
  44 beq     exit
  45 ldr     r7, [r0, #4]    /* read rp */
  46 cmp     r7, r8                  /* wait until rp != wp */
  47 beq     wait_fifo
  48
  49 mainloop:
  50 str             r2, [r4, #0x00] /* FLSH_ADDR - write address */
  51 add             r2, r2, #4              /* increment target address */
  52 ldr             r8, [r7], #4
  53 str             r8, [r4, #0x30] /* FLSH_DATA0 - write data */
  54 ldr             r5, [r4, #0x08] /* FLSH_CN */
  55 orr             r5, r5, #1
  56 str             r5, [r4, #0x08] /* FLSH_CN - enable write */
  57 busy:
  58 ldr             r8, [r4, #0x08] /* FLSH_CN */
  59 tst             r8, #1
  60 bne             busy
  61
  62 cmp     r7, r1                  /* wrap rp at end of buffer */
  63 it      cs
  64 addcs   r7, r0, #8              /* skip loader args */
  65 str     r7, [r0, #4]    /* store rp */
  66 subs    r3, r3, #1              /* decrement word count */
  67 cbz     r3, exit                /* loop if not done */
  68 b               wait_fifo
  69 exit:
  70 bkpt