contrib/loaders/flash/max32xxx/max32xxx.s

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2
   3 /***************************************************************************
   4  *   Copyright (C) 2016 by Maxim Integrated                                *
   5  *   Kevin Gillespie <kevin.gillespie@maximintegrated.com                  *
   6  ***************************************************************************/
   7
   8 .text
   9 .syntax unified
  10 .cpu cortex-m3
  11 .thumb
  12 .thumb_func
  13
  14 /*
  15  * Params :
  16  * r0 = workarea start
  17  * r1 = workarea end
  18  * r2 = target address
  19  * r3 = count (32bit words)
  20  * r4 = pFLASH_CTRL_BASE
  21  *
  22  * Clobbered:
  23  * r5 = FLASHWRITECMD
  24  * r7 - rp
  25  * r8 - wp, tmp
  26  */
  27
  28 write:
  29
  30 wait_fifo:
  31 ldr     r8, [r0, #0]    /* read wp */
  32 cmp     r8, #0                  /* abort if wp == 0 */
  33 beq     exit
  34 ldr     r7, [r0, #4]    /* read rp */
  35 cmp     r7, r8                  /* wait until rp != wp */
  36 beq     wait_fifo
  37
  38 mainloop:
  39 str             r2, [r4, #0x00] /* FLSH_ADDR - write address */
  40 add             r2, r2, #4              /* increment target address */
  41 ldr             r8, [r7], #4
  42 str             r8, [r4, #0x30] /* FLSH_DATA0 - write data */
  43 ldr             r5, [r4, #0x08] /* FLSH_CN */
  44 orr             r5, r5, #1
  45 str             r5, [r4, #0x08] /* FLSH_CN - enable write */
  46 busy:
  47 ldr             r8, [r4, #0x08] /* FLSH_CN */
  48 tst             r8, #1
  49 bne             busy
  50
  51 cmp     r7, r1                  /* wrap rp at end of buffer */
  52 it      cs
  53 addcs   r7, r0, #8              /* skip loader args */
  54 str     r7, [r0, #4]    /* store rp */
  55 subs    r3, r3, #1              /* decrement word count */
  56 cbz     r3, exit                /* loop if not done */
  57 b               wait_fifo
  58 exit:
  59 bkpt