OK6410 uboot1.1.16/lib.arm的board.c相关函数分析（C语言执行的第一个函数start_armboot）

本文主要分析了OK6410设备上uboot1.1.16版本中lib.arm目录下的board.c文件中的关键函数，特别是C语言执行的第一个函数start_armboot，内容涉及链接器、优化和闪存操作。

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在分析该函数之前，首先贴两个图

贴上相关代码

void start_armboot (void)
{
init_fnc_t **init_fnc_ptr;
char *s;
#ifndef CFG_NO_FLASH
ulong size;
#endif

#if defined(CONFIG_VFD) || defined(CONFIG_LCD)
unsigned long addr;
#endif

#if defined(CONFIG_BOOT_MOVINAND)
uint *magic = (uint *) (PHYS_SDRAM_1);
#endif

/* Pointer is writable since we allocated a register for it */
#ifdef CONFIG_MEMORY_UPPER_CODE /* by scsuh */
ulong gd_base;

gd_base = CFG_UBOOT_BASE + CFG_UBOOT_SIZE - CFG_MALLOC_LEN - CFG_STACK_SIZE - sizeof(gd_t);
#ifdef CONFIG_USE_IRQ
gd_base -= (CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ);
#endif
gd = (gd_t*)gd_base;
#else
gd = (gd_t*)(_armboot_start - CFG_MALLOC_LEN - sizeof(gd_t));
#endif

/* compiler optimization barrier needed for GCC >= 3.4 */
__asm__ __volatile__("": : :"memory");

memset ((void*)gd, 0, sizeof (gd_t));
gd->bd = (bd_t*)((char*)gd - sizeof(bd_t));
memset (gd->bd, 0, sizeof (bd_t));

monitor_flash_len = _bss_start - _armboot_start;

for (init_fnc_ptr = init_sequence; *init_fnc_ptr; ++init_fnc_ptr) {
  if ((*init_fnc_ptr)() != 0) {
   hang ();
  }
}

#ifndef CFG_NO_FLASH
/* configure available FLASH banks */
size = flash_init ();
display_flash_config (size);
#endif /* CFG_NO_FLASH */

#ifdef CONFIG_VFD
# ifndef PAGE_SIZE
# define PAGE_SIZE 4096
# endif
/*
* reserve memory for VFD display (always full pages)
*/
/* bss_end is defined in the board-specific linker script */
addr = (_bss_end + (PAGE_SIZE - 1)) & ~(PAGE_SIZE - 1);
size = vfd_setmem (addr);
gd->fb_base = addr;
#endif /* CONFIG_VFD */

#ifdef CONFIG_LCD
# ifndef PAGE_SIZE
# define PAGE_SIZE 4096
# endif
/*
* reserve memory for LCD display (always full pages)
*/
/* bss_end is defined in the board-specific linker script */
addr = (_bss_end + (PAGE_SIZE - 1)) & ~(PAGE_SIZE - 1);
size = lcd_setmem (addr);
gd->fb_base = addr;
#endif /* CONFIG_LCD */

/* armboot_start is defined in the board-specific linker script */
#ifdef CONFIG_MEMORY_UPPER_CODE /* by scsuh */
mem_malloc_init (CFG_UBOOT_BASE + CFG_UBOOT_SIZE - CFG_MALLOC_LEN - CFG_STACK_SIZE);
#else
mem_malloc_init (_armboot_start - CFG_MALLOC_LEN);
#endif

#if defined(CONFIG_SMDK6400) || defined(CONFIG_SMDK6410) || defined(CONFIG_SMDK6430) || defined(CONFIG_SMDK2450) || defined(CONFIG_SMDK2416)

#if defined(CONFIG_NAND)
puts ("NAND: ");
nand_init(); /* go init the NAND */
#endif

#if defined(CONFIG_ONENAND)
puts ("OneNAND: ");
onenand_init(); /* go init the One-NAND */
#endif

#if defined(CONFIG_BOOT_MOVINAND)
puts ("SD/MMC: ");

if ((0x24564236 == magic[0]) && (0x20764316 == magic[1])) {
  printf("Boot up for burning/n");
} else {
  movi_set_capacity();
  movi_set_ofs(MOVI_TOTAL_BLKCNT);
  movi_init();
}
#endif

#else

#if (CONFIG_COMMANDS & CFG_CMD_NAND)
puts ("NAND: ");
nand_init(); /* go init the NAND */
#endif

#endif

#ifdef CONFIG_HAS_DATAFLASH
AT91F_DataflashInit();
dataflash_print_info();
#endif

/* initialize environment */
env_relocate ();

#ifdef CONFIG_VFD
/* must do this after the framebuffer is allocated */
drv_vfd_init();
#endif /* CONFIG_VFD */

/* IP Address */
gd->bd->bi_ip_addr = getenv_IPaddr ("ipaddr");

/* MAC Address */
{
  int i;
  ulong reg;
  char *s, *e;
  char tmp[64];

i = getenv_r ("ethaddr", tmp, sizeof (tmp));
s = (i > 0) ? tmp : NULL;

  for (reg = 0; reg < 6; ++reg) {
   gd->bd->bi_enetaddr[reg] = s ? simple_strtoul (s, &e, 16) : 0;
   if (s)
    s = (*e) ? e + 1 : e;
  }

#ifdef CONFIG_HAS_ETH1
i = getenv_r ("eth1addr", tmp, sizeof (tmp));
s = (i > 0) ? tmp : NULL;

  for (reg = 0; reg < 6; ++reg) {
   gd->bd->bi_enet1addr[reg] = s ? simple_strtoul (s, &e, 16) : 0;
   if (s)
    s = (*e) ? e + 1 : e;
  }
#endif
}

devices_init (); /* get the devices list going. */

#ifdef CONFIG_CMC_PU2
load_sernum_ethaddr ();
#endif /* CONFIG_CMC_PU2 */

jumptable_init ();

console_init_r (); /* fully init console as a device */

#if defined(CONFIG_MISC_INIT_R)
/* miscellaneous platform dependent initialisations */
misc_init_r ();
#endif

/* enable exceptions */
enable_interrupts ();

/* Perform network card initialisation if necessary */
#ifdef CONFIG_DRIVER_CS8900
//cs8900_get_enetaddr (gd->bd->bi_enetaddr);
#endif

#if defined(CONFIG_DRIVER_SMC91111) || defined (CONFIG_DRIVER_LAN91C96)
if (getenv ("ethaddr")) {
smc_set_mac_addr(gd->bd->bi_enetaddr);
}
#endif /* CONFIG_DRIVER_SMC91111 || CONFIG_DRIVER_LAN91C96 */

/* Initialize from environment */
if ((s = getenv ("loadaddr")) != NULL) {
load_addr = simple_strtoul (s, NULL, 16);
}
#if (CONFIG_COMMANDS & CFG_CMD_NET)
if ((s = getenv ("bootfile")) != NULL) {
copy_filename (BootFile, s, sizeof (BootFile));
}
#endif /* CFG_CMD_NET */

#ifdef BOARD_LATE_INIT
board_late_init ();
#endif
#if (CONFIG_COMMANDS & CFG_CMD_NET)
#if defined(CONFIG_NET_MULTI)
puts ("Net: ");
#endif
eth_initialize(gd->bd);
#endif
/* main_loop() can return to retry autoboot, if so just run it again. */
for (;;) {
main_loop ();
}

/* NOTREACHED - no way out of command loop except booting */
}

接下来就该分析该函数了，太晚了，明天继续，哈哈