//初始化全局数据区域为0
memset ((void*)gd, 0, sizeof (gd_t));
//为指向bd_t的数据结构的指针赋值，gd-sizeof(bd_t);
gd->bd = (bd_t*)((char*)gd - sizeof(bd_t));
memset (gd->bd, 0, sizeof (bd_t));
//为全局数据结构里面的标志flags 赋值为：GD_FLG_RELOC表示已经重定位到ram
gd->flags |= GD_FLG_RELOC;
//monitor_flash_len就是u-boot代码长度
monitor_flash_len = _bss_start - _armboot_start;
//调用一系列的初始化函数,这些函数的指针放在init_sequence数组中
for (init_fnc_ptr = init_sequence; *init_fnc_ptr; ++init_fnc_ptr) {
if ((*init_fnc_ptr)() != 0) {
hang ();
}
}
//mem_malloc_init函数做2个事情：一是为全局变量赋值，二是初始化malloc room
//mem_malloc_start = start;
//mem_malloc_end = start + size;
//mem_malloc_brk = start;
//memset((void *)mem_malloc_start, 0, size);
/* armboot_start is defined in the board-specific linker script */
mem_malloc_init (_armboot_start - CONFIG_SYS_MALLOC_LEN,
CONFIG_SYS_MALLOC_LEN);
#ifndef CONFIG_SYS_NO_FLASH
/* configure available FLASH banks */
//因为我要移植的是s3c2440,flash_init这个函数在/board/samsung/
//smdk2440/flash.c中，而函数display_flash_config 仅仅是显示flash大小
display_flash_config (flash_init ());
#endif /* CONFIG_SYS_NO_FLASH */
//LCD并不是移植的重点
/***************************LCD***********************************/
#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);
vfd_setmem (addr);
gd->fb_base = addr;
#endif /* CONFIG_VFD */
#ifdef CONFIG_LCD
/* board init may have inited fb_base */
if (!gd->fb_base) {
# 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);
lcd_setmem (addr);
gd->fb_base = addr;
}
#endif /* CONFIG_LCD */
/***************************LCD***********************************/
//要在smdk2440.h中添加对CONFIG_CMD_NAND宏的定义。初始化Nand
#if defined(CONFIG_CMD_NAND)
puts ("NAND: ");
nand_init(); /* go init the NAND */
#endif
#if defined(CONFIG_CMD_ONENAND)
onenand_init();
#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 */
#ifdef CONFIG_SERIAL_MULTI
serial_initialize();
#endif
/* IP Address */
gd->bd->bi_ip_addr = getenv_IPaddr ("ipaddr");
stdio_init (); /* get the devices list going. */
jumptable_init ();
#if defined(CONFIG_API)
/* Initialize API */
api_init ();
#endif
console_init_r (); /* fully init console as a device */
#if defined(CONFIG_ARCH_MISC_INIT)
/* miscellaneous arch dependent initialisations */
arch_misc_init ();
#endif
#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_TI_EMAC
/* XXX: this needs to be moved to board init */
extern void davinci_eth_set_mac_addr (const u_int8_t *addr);
if (getenv ("ethaddr")) {
uchar enetaddr[6];
eth_getenv_enetaddr("ethaddr", enetaddr);
davinci_eth_set_mac_addr(enetaddr);
}
#endif
#if defined(CONFIG_DRIVER_SMC91111) || defined (CONFIG_DRIVER_LAN91C96)
/* XXX: this needs to be moved to board init */
if (getenv ("ethaddr")) {
uchar enetaddr[6];
eth_getenv_enetaddr("ethaddr", enetaddr);
smc_set_mac_addr(enetaddr);
}
#endif /* CONFIG_DRIVER_SMC91111 || CONFIG_DRIVER_LAN91C96 */
/* Initialize from environment */
if ((s = getenv ("loadaddr")) != NULL) {
load_addr = simple_strtoul (s, NULL, 16);
}
#if defined(CONFIG_CMD_NET)
if ((s = getenv ("bootfile")) != NULL) {
copy_filename (BootFile, s, sizeof (BootFile));
}
#endif
#ifdef BOARD_LATE_INIT
board_late_init ();
#endif
#ifdef CONFIG_GENERIC_MMC
puts ("MMC: ");
mmc_initialize (gd->bd);
#endif
#ifdef CONFIG_BITBANGMII
bb_miiphy_init();
#endif
#if defined(CONFIG_CMD_NET)
#if defined(CONFIG_NET_MULTI)
puts ("Net: ");
#endif
eth_initialize(gd->bd);
#if defined(CONFIG_RESET_PHY_R)
debug ("Reset Ethernet PHY\n");
reset_phy();
#endif
#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 */
}
