/lib_arm/board.c 主要完成了一些初始化的操作，最重要的是有start_armboot函数 _armboot_start地址为多少？？ /* * * U-Boot code: 00F00000 -> 00F3C774 BSS: -> 00FC3274 * IRQ Stack: 00ebff7c * FIQ Stack: 00ebef7c */ #include <common.h> #include <command.h> #include <malloc.h> #include <devices.h> #include <version.h> #include <net.h> #ifdef CONFIG_DRIVER_SMC91111 #include "../drivers/smc91111.h" #endif #ifdef CONFIG_DRIVER_LAN91C96 应该是关于网卡的定义 #include "../drivers/lan91c96.h" #endif DECLARE_GLOBAL_DATA_PTR //声明全局数据指针 #if (CONFIG_COMMANDS & CFG_CMD_NAND) void nand_init (void); 声明这个方法 #endif ulong monitor_flash_len; #ifdef CONFIG_HAS_DATAFLASH extern int AT91F_DataflashInit(void); extern void dataflash_print_info(void); #endif #ifndef CONFIG_IDENT_STRING 如果没有定义，CONFIG_IDENT_STRING就定义为空 #define CONFIG_IDENT_STRING "" #endif const char version_string[] =版本字符串 U_BOOT_VERSION" (" __DATE__ " - " __TIME__ ")"CONFIG_IDENT_STRING; #ifdef CONFIG_DRIVER_CS8900 如果是CS8900网卡，则声明下面的函数。好像是获取网址的意思 extern void cs8900_get_enetaddr (uchar * addr); #endif #ifdef CONFIG_DRIVER_RTL8019 extern void rtl8019_get_enetaddr (uchar * addr); #endif /* * Begin and End of memory area for malloc(), and current "brk" malloc用于用户程序进行分配内存 */ static ulong mem_malloc_start = 0; static ulong mem_malloc_end = 0; static ulong mem_malloc_brk = 0; static void mem_malloc_init (ulong dest_addr) 内存分配初始函数。 { mem_malloc_start = dest_addr; mem_malloc_end = dest_addr + CFG_MALLOC_LEN; mem_malloc_brk = mem_malloc_start; memset ((void *) mem_malloc_start, 0, mem_malloc_end - mem_malloc_start); 真正实现内存分配的函数。分配了一个CFG_MALLOC_LEN大小的内存空间 } void *sbrk (ptrdiff_t increment) 所分配内存区的brk指针调整。 { ulong old = mem_malloc_brk; ulong new = old + increment; if ((new < mem_malloc_start) || (new > mem_malloc_end)) { return (NULL); } mem_malloc_brk = new; return ((void *) old); } /************************************************************************ * Init Utilities * ************************************************************************ * Some of this code should be moved into the core functions, * or dropped completely, * but let's get it working (again) first... */ 下面就是一系列的初始化操作。 static int init_baudrate (void) 初始化波特率 { char tmp[64]; /* long enough for environment variables */ int i = getenv_r ("baudrate", tmp, sizeof (tmp)); gd->bd->bi_baudrate = gd->baudrate = (i > 0) ? (int) simple_strtoul (tmp, NULL, 10) : CONFIG_BAUDRATE; return (0); } static int display_banner (void) 一些显示函数。显示IRQ_STACK_START等的地址 _armboot_start, _bss_start, _bss_end 这些值 { printf (" %s ", version_string); debug ("U-Boot code: %08lX -> %08lX BSS: -> %08lX ", _armboot_start, _bss_start, _bss_end); #ifdef CONFIG_MODEM_SUPPORT debug ("Modem Support enabled "); #endif #ifdef CONFIG_USE_IRQ debug ("IRQ Stack: %08lx ", IRQ_STACK_START); debug ("FIQ Stack: %08lx ", FIQ_STACK_START); #endif return (0); } /* * WARNING: this code looks "cleaner" than the PowerPC version, but * has the disadvantage that you either get nothing, or everything. * On PowerPC, you might see "DRAM: " before the system hangs - which * gives a simple yet clear indication which part of the * initialization if failing. */ static int display_dram_config (void) 显示内存的配置，打印出DRAM的大小 { int i; #ifdef DEBUG puts ("RAM Configuration: "); for(i=0; i<CONFIG_NR_DRAM_BANKS; i++) { printf ("Bank #%d: %08lx ", i, gd->bd->bi_dram[i].start); print_size (gd->bd->bi_dram[i].size, " "); } #else ulong size = 0; for (i=0; i<CONFIG_NR_DRAM_BANKS; i++) { size += gd->bd->bi_dram[i].size; } puts("DRAM: "); print_size(size, " "); #endif return (0); } #ifndef CFG_NO_FLASH static void display_flash_config (ulong size) { puts ("Flash: "); print_size (size, " "); } #endif /* CFG_NO_FLASH */ /*初始化一个串行口作为控制台，同时进行一些硬件测试 * Breathe some life into the board... * * Initialize a serial port as console, and carry out some hardware * tests. * * The first part of initialization is running from Flash memory; * its main purpose is to initialize the RAM so that we * can relocate the monitor code to RAM. */ 不存在一个common 即通用的初始化序列来为所有的开发板及结构进行初始化。因为不同的体系结构差别还是比较大的。 /* * All attempts to come up with a "common" initialization sequence * that works for all boards and architectures failed: some of the * requirements are just _too_ different. To get rid of the resulting * mess of board dependent #ifdef'ed code we now make the whole * initialization sequence configurable to the user. * * The requirements for any new initalization function is simple: it * receives a pointer to the "global data" structure as it's only * argument, and returns an integer return code, where 0 means * "continue" and != 0 means "fatal error, hang the system". */通过接受一个指向全局数据的指针作为唯一的参数。 typedef int (init_fnc_t) (void); int print_cpuinfo (void); /* test-only */ init_fnc_t *init_sequence[] = {定义一个初始化的整型指针数组 cpu_init, /* basic cpu dependent setup *//cpu/arm920t/cpu.c 这个函数在cpu.c函数中定义了 board_init, /* basic board dependent setup *//board/smdk2410/smdk2410.c interrupt_init, /* set up exceptions */ env_init, /* initialize environment */tools/env/FW_env.c init_baudrate, /* initialze baudrate settings */ serial_init, /* serial communications setup */ console_init_f, /* stage 1 init of console */ display_banner, /* say that we are here */ #if defined(CONFIG_DISPLAY_CPUINFO) 显示cpu的信息 print_cpuinfo, /* display cpu info (and speed) */ #endif #if defined(CONFIG_DISPLAY_BOARDINFO) 显示板的信息 checkboard, /* display board info */ #endif dram_init, /* configure available RAM banks */ display_dram_config, NULL, }; void start_armboot (void) { init_fnc_t **init_fnc_ptr;定义一个双重整型指针。 char *s; #ifndef CFG_NO_FLASH ulong size; #endif #if defined(CONFIG_VFD) || defined(CONFIG_LCD) unsigned long addr; #endif /* Pointer is writable since we allocated a register for it */ gd = (gd_t*)(_armboot_start - CFG_MALLOC_LEN - sizeof(gd_t)); _armboot_start为0x33f80000，CFG_MALLOC_LEN是堆大小加环境数据区大小，在smdk2410.h中有定义 #define CFG_MALLOC_LEN (CFG_ENV_SIZE + 128*1024) CFG_ENV_SIZE为64K，所以共192K /* compiler optimization barrier needed for GCC >= 3.4 */ __asm__ __volatile__("": : :"memory"); memset ((void*)gd, 0, sizeof (gd_t));获得一个gd指针，给全局数据变量gd分配内存 gd->bd = (bd_t*)((char*)gd - sizeof(bd_t)); memset (gd->bd, 0, sizeof (bd_t));给板子数据变量分配内存空间 monitor_flash_len = _bss_start - _armboot_start;取整个代码区Uboot的长度 顺序执行init_sequence数组中的初始化函数 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 */从其实现上来看，好像只是配置nor flash size = flash_init (); display_flash_config (size);显示flash的信息 #endif /* CFG_NO_FLASH */ #ifdef CONFIG_VFD 定义显示类型 # 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);按页对齐的方式保留显存 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);同上 size = lcd_setmem (addr); gd->fb_base = addr; #endif /* CONFIG_LCD */ /* armboot_start is defined in the board-specific linker script */ 初始化CFG_MALLOC_LEN大小空间 mem_malloc_init (_armboot_start - CFG_MALLOC_LEN); #if (CONFIG_COMMANDS & CFG_CMD_NAND) 初始化nandflash,这是在nandflash启动的s3c2410移植Uboot的关键，根据flash时序编写函数即可。首先要在include/configs/smdk2410.h中打开CFG_CMD_NAND命令 puts ("NAND: "); nand_init(); /* go init the NAND */,这个函数在前面被声明过，现在就可以直接使用了/board/smdk2410/smdk2410.c中没有定义这个函数，需要添加 #endif #ifdef CONFIG_HAS_DATAFLASH AT91F_DataflashInit(); dataflash_print_info(); #endif /* initialize environment */ env_relocate ();初始化环境参数 #ifdef CONFIG_VFD /* must do this after the framebuffer is allocated */ drv_vfd_init();framebuffer初始化 #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; }获取网卡地址 #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. */调用相应驱动函数对硬件设备进行初始化 #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 ();开中断 /* 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 */ } void hang (void) { puts ("### ERROR ### Please RESET the board ### "); for (;;); } ....... 后面是modem的配置 不用管