contrib/loaders/flash/lpcspifi_init.S

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2
   3 /***************************************************************************
   4  *   Copyright (C) 2012 by George Harris                                           *
   5  *   george@luminairecoffee.com                                            *
   6  ***************************************************************************/
   7
   8 /***************************************************************************
   9 *       This is an algorithm for the LPC43xx family (and probably the LPC18xx  *
  10 *       family as well, though they have not been tested) that will initialize *
  11 *       memory-mapped SPI flash accesses. Unfortunately NXP has published      *
  12 *       neither the ROM source code that performs this initialization nor the  *
  13 *       register descriptions necessary to do so, so this code is necessary to *
  14 *       call into the ROM SPIFI API.                                           *
  15 ***************************************************************************/
  16
  17         .text
  18         .syntax unified
  19         .arch armv7-m
  20         .thumb
  21         .thumb_func
  22
  23         .align 2
  24
  25 /*
  26  * Params :
  27  * r0 = spifi clock speed
  28  */
  29
  30 #define IOCONFIG_BASE_HIGH          0x4008
  31 #define IOCONFIG_BASE_LOW           0x6000
  32 #define IOCONFIG_SCK_OFFSET         0x18c
  33 #define IOCONFIG_HOLD_OFFSET        0x190
  34 #define IOCONFIG_WP_OFFSET          0x194
  35 #define IOCONFIG_MISO_OFFSET        0x198
  36 #define IOCONFIG_MOSI_OFFSET        0x19c
  37 #define IOCONFIG_CS_OFFSET          0x1a0
  38
  39 #define SPIFI_ROM_TABLE_BASE_HIGH   0x1040
  40 #define SPIFI_ROM_TABLE_BASE_LOW    0x0118
  41
  42 code:
  43         mov.w   r8, r0
  44         sub             sp, #0x84
  45         add             r7, sp, #0x0
  46         /* Initialize SPIFI pins */
  47         mov.w   r3, #IOCONFIG_BASE_LOW
  48         movt    r3, #IOCONFIG_BASE_HIGH
  49         mov.w   r2, #0xf3
  50         str.w   r2, [r3, #IOCONFIG_SCK_OFFSET]
  51         mov.w   r3, #IOCONFIG_BASE_LOW
  52         movt    r3, #IOCONFIG_BASE_HIGH
  53         mov.w   r2, #IOCONFIG_BASE_LOW
  54         movt    r2, #IOCONFIG_BASE_HIGH
  55         mov.w   r1, #IOCONFIG_BASE_LOW
  56         movt    r1, #IOCONFIG_BASE_HIGH
  57         mov.w   r0, #IOCONFIG_BASE_LOW
  58         movt    r0, #IOCONFIG_BASE_HIGH
  59         mov.w   r4, #0xd3
  60         str.w   r4, [r0, #IOCONFIG_MOSI_OFFSET]
  61         mov     r0, r4
  62         str.w   r0, [r1, #IOCONFIG_MISO_OFFSET]
  63         mov     r1, r0
  64         str.w   r1, [r2, #IOCONFIG_WP_OFFSET]
  65         str.w   r1, [r3, #IOCONFIG_HOLD_OFFSET]
  66         mov.w   r3, #IOCONFIG_BASE_LOW
  67         movt    r3, #IOCONFIG_BASE_HIGH
  68         mov.w   r2, #0x13
  69         str.w   r2, [r3, #IOCONFIG_CS_OFFSET]
  70
  71         /* Perform SPIFI init. See spifi_rom_api.h (in NXP lpc43xx driver package) for details */
  72         /* on initialization arguments. */
  73         movw    r3, #SPIFI_ROM_TABLE_BASE_LOW      /* The ROM API table is located @ 0x10400118, and                    */
  74         movt    r3, #SPIFI_ROM_TABLE_BASE_HIGH     /* the first pointer in the struct is to the init function. */
  75         ldr     r3, [r3, #0x0]
  76         ldr     r4, [r3, #0x0]                           /* Grab the init function pointer from the table */
  77         /* Set up function arguments */
  78         movw    r0, #0x3b4
  79         movt    r0, #0x1000                                   /* Pointer to a SPIFI data struct that we don't care about */
  80         mov.w   r1, #0x3                        /* "csHigh". Not 100% sure what this does. */
  81         mov.w   r2, #0xc0                                     /* The configuration word: S_RCVCLOCK | S_FULLCLK */
  82         mov.w   r3, r8                                        /* SPIFI clock speed (12MHz) */
  83         blx     r4                                                          /* Call the init function */
  84         b               done
  85
  86 done:
  87         bkpt    #0
  88
  89         .end