contrib/loaders/flash/kinetis_ke/kinetis_ke_flash.s

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2
   3 /***************************************************************************
   4  *   Copyright (C) 2015 by Ivan Meleca                                     *
   5  *   ivan@artekit.eu                                                       *
   6  ***************************************************************************/
   7
   8         /* Params:
   9          * r0 = flash destination address, status
  10          * r1 = longword count
  11          * r2 = workarea start address
  12          * r3 = workarea end address
  13          */
  14
  15         .text
  16         .cpu cortex-m0plus
  17         .code 16
  18         .thumb_func
  19
  20         .align  2
  21
  22         /* r5 = rp
  23          * r6 = wp, tmp
  24          * r7 = tmp
  25          */
  26
  27 wait_fifo:
  28         ldr     r6, [r2, #0]    /* read wp */
  29         cmp     r6, #0                  /* abort if wp == 0 */
  30         beq     exit
  31         ldr     r5, [r2, #4]    /* read rp */
  32         cmp     r5, r6                  /* wait until rp != wp */
  33         beq     wait_fifo
  34
  35         ldr             r6, fstat               /* Clear error flags */
  36         mov             r7, #48
  37         strb    r7, [r6]
  38
  39         ldr             r6, fccobix             /* FCCOBIX = 0 */
  40         mov             r7, #0
  41         strb    r7, [r6]
  42
  43         ldr     r6, fccobhi             /* Program FLASH command */
  44         mov             r7, #6                  /* FCCOBHI = 6 */
  45         strb    r7, [r6]
  46
  47         lsr             r7, r0, #16             /* FCCOBLO = flash destination address >> 16 */
  48         ldr             r6, fccoblo
  49         strb    r7, [r6]
  50
  51         ldr             r6, fccobix             /* Index for lower byte address bits[15:0] */
  52         mov             r7, #1
  53         strb    r7, [r6]                /* FCCOBIX = 1*/
  54
  55         uxtb    r7, r0                  /* Memory address bits[15:0] */
  56         ldr     r6, fccoblo
  57         strb    r7, [r6]                /* FCCOBLO = flash destination address */
  58
  59         lsr             r7, r0, #8
  60         ldr             r6, fccobhi
  61         strb    r7, [r6]                /* FCCOBHI = flash destination address >> 8 */
  62
  63         ldr             r6, fccobix             /* FCCOBIX = 2 */
  64         mov             r7, #2
  65         strb    r7, [r6]
  66
  67         ldrb    r7, [r5, #1]    /* FCCOBHI = rp >> 8 */
  68         ldr             r6, fccobhi
  69         strb    r7, [r6]
  70
  71         ldrb    r7, [r5]                /* FCCOBLO = rp */
  72         ldr     r6, fccoblo
  73         strb    r7, [r6]
  74
  75         ldr             r6, fccobix             /* FCCOBIX = 3 */
  76         mov             r7, #3
  77         strb    r7, [r6]
  78
  79         ldrb    r7, [r5, #3]    /* FCCOBHI = rp >> 24 */
  80         ldr             r6, fccobhi
  81         strb    r7, [r6]
  82
  83         ldrb    r7, [r5, #2]    /* FCCOBLO = rp >> 16 */
  84         ldr             r6, fccoblo
  85         strb    r7, [r6]
  86
  87         sub             r1, r1, #1              /* Two words (4 bytes) queued, decrement counter */
  88         add             r0, r0, #4              /* flash address += 4 */
  89         add             r5, r5, #4              /* rp += 4 */
  90
  91         cmp     r5, r3                  /* Wrap? */
  92         bcc     no_wrap
  93         mov     r5, r2
  94         add     r5, r5, #8
  95
  96 no_wrap:
  97         cmp             r1, #0                  /* Done? */
  98         beq             execute
  99
 100         ldr     r6, [r2, #0]    /* read wp */
 101         cmp     r6, r5
 102         beq             execute                 /* execute if rp == wp */
 103
 104         ldr             r6, fccobix             /* FCCOBIX = 4 */
 105         mov             r7, #4
 106         strb    r7, [r6]
 107
 108         ldrb    r7, [r5, #1]    /* FCCOBHI = rp >> 8 */
 109         ldr             r6, fccobhi
 110         strb    r7, [r6]
 111
 112         ldrb    r7, [r5]                /* FCCOBLO = rp */
 113         ldr     r6, fccoblo
 114         strb    r7, [r6]
 115
 116         ldr             r6, fccobix             /* FCCOBIX = 5 */
 117         mov             r7, #5
 118         strb    r7, [r6]
 119
 120         ldrb    r7, [r5, #3]    /* FCCOBHI = rp >> 24 */
 121         ldr             r6, fccobhi
 122         strb    r7, [r6]
 123
 124         ldrb    r7, [r5, #2]    /* FCCOBLO = rp >> 16 */
 125         ldr             r6, fccoblo
 126         strb    r7, [r6]
 127
 128         sub             r1, r1, #1              /* Two words (4 bytes) queued, decrement counter */
 129         add             r0, r0, #4              /* flash address += 4 */
 130         add             r5, r5, #4              /* rp += 4 */
 131
 132         cmp     r5, r3                  /* Wrap? */
 133         bcc     execute
 134         mov     r5, r2
 135         add     r5, r5, #8
 136
 137 execute:
 138         ldr             r6, fstat               /* Launch the command */
 139         mov             r7, #128
 140         strb    r7, [r6]
 141
 142 wait_busy:
 143         ldr             r6, fstat
 144         ldrb    r6, [r6]                /* Wait until finished */
 145         tst             r6, r7
 146         beq             wait_busy
 147
 148         mov             r7, #48                 /* Check error */
 149         tst             r6, r7
 150         bne             error
 151
 152         mov             r6, #0                  /* Clear error */
 153
 154         str     r5, [r2, #4]    /* Store rp */
 155
 156         cmp             r1, #0                  /* Done? */
 157         beq             done
 158         b               wait_fifo
 159
 160 error:
 161         mov             r0, #0
 162         str     r0, [r2, #4]    /* set rp = 0 on error */
 163
 164 done:
 165         mov             r0, r6                  /* Set result code */
 166         bkpt    #0
 167
 168         .align  2
 169 fstat:
 170         .word   0
 171 fccobix:
 172         .word   0
 173 fccobhi:
 174         .word   0
 175 fccoblo:
 176         .word   0