ARMBoot-1.1.0 在 mini2440 开发板上的移植

和CONFIG_SMDK2410相关的：
[root@www.linuxidc.com armboot-1.1.0]# grep -rHn CONFIG_SMDK2410 *
cpu/arm920t/serial.c:45:#elif defined(CONFIG_SMDK2410)
include/configs/config_smdk2410.h:44:#define CONFIG_SMDK2410            1       /* on an SAMSUNG SMDK2410 Board */

看程序的连接脚本： board/mini2440/armboot.lds
    33          .text      :
    34          {
    35            cpu/arm920t/start.o   (.text)
    36            *(.text)
    37            }
   
知道程序的入口在cpu/arm920t/start.S上（现在U-boot中的该文件还保持着原有的风格）
查看该文件，知道整个程序的主要调用顺序为：
cpu_init_crit-> memsetup(在board/mini2440/memsetup.S中)
->start_armboot (在common/board.c中)
void start_armboot(void)进行了一系列的初始化工作，最后就进入  
 for (;;) {
    main_loop(&bd);
    }
主要是接受串口命令，分析并执行命令的循环中。

*************************************************************************************************************************************************
** 各个相关文件的修改 (为了便于说明，代码加了行号（所有新修改的代码均有snallie字样的注释，以示区别,并在代码段的下方对应中文注释说明)
*************************************************************************************************************************************************

////////////////////////
cpu/arm920t/start.S的修改

     1    /*
     2     *  armboot - Startup Code for ARM920 CPU-core
     3     *
     4     *  Copyright (c) 2001    Marius Gr鰃er
     5     *  Copyright (c) 2002    Alex Z黳ke
     6     *  Copyright (c) 2002    Gary Jennejohn
     7     *
     8     * See file CREDITS for list of people who contributed to this
     9     * project.
    10     *
    11     * This program is free software; you can redistribute it and/or
    12     * modify it under the terms of the GNU General Public License as
    13     * published by the Free Software Foundation; either version 2 of
    14     * the License, or (at your option) any later version.
    15     *
    16     * This program is distributed in the hope that it will be useful,
    17     * but WITHOUT ANY WARRANTY; without even the implied warranty of
    18     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    19     * GNU General Public License for more details.
    20     *
    21     * You should have received a copy of the GNU General Public License
    22     * along with this program; if not, write to the Free Software
    23     * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
    24     * MA 02111-1307 USA
    25     */
    26   
    27   
    28   
    29    #include 'config.h'
    30    #include 'version.h'
    31   
    32   
    33    /*
    34     *************************************************************************
    35     *
    36     * Jump vector table as in table 3.1 in [1]
    37     *
    38     *************************************************************************
    39     */
    40   
    41   
    42    .globl _start
    43    _start:    b       reset
    44        ldr    pc, _undefined_instruction
    45        ldr    pc, _software_interrupt
    46        ldr    pc, _prefetch_abort
    47        ldr    pc, _data_abort
    48        ldr    pc, _not_used
    49        ldr    pc, _irq
    50        ldr    pc, _fiq
    51   
    52    _undefined_instruction:    .word undefined_instruction
    53    _software_interrupt:    .word software_interrupt
    54    _prefetch_abort:    .word prefetch_abort
    55    _data_abort:        .word data_abort
    56    _not_used:        .word not_used
    57    _irq:            .word irq
    58    _fiq:            .word fiq
    59   
    60        .balignl 16,0xdeadbeef
    61   
    62   
    63    /*
    64     *************************************************************************
    65     *
    66     * Startup Code (reset vector)
    67     *
    68     * do important init only if we don't start from memory!
    69     * relocate armboot to ram
    70     * setup stack
    71     * jump to second stage
    72     *
    73     *************************************************************************
    74     */
    75   
    76    /*
    77     * CFG_MEM_END is in the board dependent config-file (configs/config_BOARD.h)
    78     */
    79    _TEXT_BASE:
    80        .word    TEXT_BASE
    81   
    82    .globl _armboot_start
    83    _armboot_start:
    84        .word _start
    85   
    86    /*
    87     * Note: armboot_end is defined by the (board-dependent) linker script
    88     */
    89    .globl _armboot_end
    90    _armboot_end:
    91        .word armboot_end
    92       
    93    // start of snallie   
    94    .globl _bss_start
    95    _bss_start:
    96          .word __bss_start
    97   
    98    .globl _bss_end
    99    _bss_end:
   100          .word armboot_end
   101    // end of snallie
        /*
         *  94~100行 为新加入的代码，定义了2个全局变量，_bss_start和_bss_end，记录未初始化段的起止地址，其中的
         *  __bss_start和armboot_end 是在连接脚本 board/mini2440/armboot.lds 中定义的，后面309~317行用_bss_start
         *  和_bss_end来进行未初始化段数据的初始清零工作。
         */
  
   102   
   103    /*
   104     * _armboot_real_end is the first usable RAM address behind armboot
   105     * and the various stacks
   106     */
   107    .globl _armboot_real_end
   108    _armboot_real_end:
   109        .word 0x0badc0de
   110   
   111    #ifdef CONFIG_USE_IRQ
   112    /* IRQ stack memory (calculated at run-time) */
   113    .globl IRQ_STACK_START
   114    IRQ_STACK_START:
   115        .word    0x0badc0de
   116   
   117    /* IRQ stack memory (calculated at run-time) */
   118    .globl FIQ_STACK_START
   119    FIQ_STACK_START:
   120        .word 0x0badc0de
   121    #endif
   122   
   123   
   124    /*
   125     * the actual reset code
   126     */
   127   
   128    reset:
   129        /*
   130         * set the cpu to SVC32 mode
   131         */
   132        mrs    r0,cpsr
   133        bic    r0,r0,#0x1f
   134        orr    r0,r0,#0xd3
   135        msr    cpsr,r0
   136   
   137    /* turn off the watchdog */
   138    #if defined(CONFIG_S3C2400)
   139    #define pWTCON        0x15300000
   140    /* Interupt-Controller base addresses */
   141    #define INTMSK        0x14400008
   142    /* clock divisor register */
   143    #define CLKDIVN        0x14800014
   144    #elif defined(CONFIG_S3C2410) || defined(CONFIG_S3C2440)  // snallie
   /* 144行 S3C2410和S3C2440的Watchdog以及中断屏蔽寄存器的地址相同，所以加入 || defined(CONFIG_S3C2440) 的判断 */