contrib/loaders/flash/sim3x.s

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2
   3 /***************************************************************************
   4  *   Copyright (C) 2014 by Ladislav Bábel                                  *
   5  *   ladababel@seznam.cz                                                   *
   6  ***************************************************************************/
   7
   8 #define INITIAL_UNLOCK    0x5A
   9 #define MULTIPLE_UNLOCK   0xF2
  10
  11 #define FLASHCTRL_KEY     0x4002E0C0
  12 #define FLASHCTRL_CONFIG  0x4002E000
  13 #define FLASHCTRL_WRADDR  0x4002E0A0
  14 #define FLASHCTRL_WRDATA  0x4002E0B0
  15 #define BUSYF             0x00100000
  16
  17
  18                 /* Write the initial unlock value to KEY (0xA5) */
  19                 movs    r6, #INITIAL_UNLOCK
  20                 str     r6, [r0, #FLASHCTRL_KEY]
  21
  22                 /* Write the multiple unlock value to KEY (0xF2) */
  23                 movs    r6, #MULTIPLE_UNLOCK
  24                 str     r6, [r0, #FLASHCTRL_KEY]
  25
  26 wait_fifo:
  27                 ldr     r6, [r2, #0]
  28                 cmp         r6, #0
  29                 beq     exit
  30                 ldr     r5, [r2, #4]
  31                 cmp     r5, r6
  32                 beq     wait_fifo
  33
  34                 /* wait for BUSYF flag */
  35 wait_busy1:
  36                 ldr     r6, [r0, #FLASHCTRL_CONFIG]
  37                 tst     r6, #BUSYF
  38                 bne     wait_busy1
  39
  40                 /* Write the destination address to WRADDR */
  41                 str     r4, [r0, #FLASHCTRL_WRADDR]
  42
  43                 /* Write the data half-word to WRDATA in right-justified format */
  44                 ldrh    r6, [r5]
  45                 str     r6, [r0, #FLASHCTRL_WRDATA]
  46
  47                 adds    r5, #2
  48                 adds    r4, #2
  49
  50                 /* wrap rp at end of buffer */
  51                 cmp     r5, r3
  52                 bcc     no_wrap
  53                 mov     r5, r2
  54                 adds    r5, #8
  55
  56 no_wrap:
  57                 str     r5, [r2, #4]
  58                 subs    r1, r1, #1
  59                 cmp     r1, #0
  60                 beq     exit
  61                 b       wait_fifo
  62
  63 exit:
  64                 movs    r6, #MULTIPLE_LOCK
  65                 str     r6, [r0, #FLASHCTRL_KEY]
  66
  67                 /* wait for BUSYF flag */
  68 wait_busy2:
  69                 ldr     r6, [r0, #FLASHCTRL_CONFIG]
  70                 tst     r6, #BUSYF
  71                 bne     wait_busy2
  72
  73                 bkpt    #0