uboot之board.c源码分析

/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

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 ((,

              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

{

     ]; /* long enough for environment variables */

     int i = getenv_r ("baudrate", tmp, sizeof (tmp));

     gd->bd->bi_baudrate = gd->baudrate = (i > )

              ? ()

              : CONFIG_BAUDRATE;

     );

}

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 ("\n\n%s\n\n", version_string);

     debug ("U-Boot code: %08lX -> %08lX  BSS: -> %08lX\n",

            _armboot_start, _bss_start, _bss_end);

#ifdef CONFIG_MODEM_SUPPORT

     debug ("Modem Support enabled\n");

#endif

#ifdef CONFIG_USE_IRQ

     debug ("IRQ Stack: %08lx\n", IRQ_STACK_START);

     debug ("FIQ Stack: %08lx\n", FIQ_STACK_START);

#endif

     );

}

/*

 * 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:\n");

     ; 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, "\n");

     }

#else

     ;

     ; i<CONFIG_NR_DRAM_BANKS; i++) {

         size += gd->bd->bi_dram[i].size;

     }

     puts("DRAM:  ");

     print_size(size, "\n");

#endif

     );

}

#ifndef CFG_NO_FLASH

static void display_flash_config (ulong size)

{

     puts ("Flash: ");

     print_size (size, "\n");

}

#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 ((, 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, , 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) {

         ) {

              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 

#    endif

     /*

      * reserve memory for VFD display (always full pages)

      */

     /* bss_end is defined in the board-specific linker script */

     addr = (_bss_end + (PAGE_SIZE - )) & ~(PAGE_SIZE - );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 

#    endif

     /*

      * reserve memory for LCD display (always full pages)

      */

     /* bss_end is defined in the board-specific linker script */

     addr = (_bss_end + (PAGE_SIZE - )) & ~(PAGE_SIZE - );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;

         ];

         i = getenv_r ("ethaddr", tmp, sizeof (tmp));

         s = (i > ) ? tmp : NULL;

         ; reg < ; ++reg) {

              gd->bd->bi_enetaddr[reg] = s ? simple_strtoul (s, &e, ) : ;

              if (s)

                   s = (*e) ? e +  : e;

         }获取网卡地址

#ifdef CONFIG_HAS_ETH1

         i = getenv_r ("eth1addr", tmp, sizeof (tmp));

         s = (i > ) ? tmp : NULL;

         ; reg < ; ++reg) {

              gd->bd->bi_enet1addr[reg] = s ? simple_strtoul (s, &e, ) : ;

              if (s)

                   s = (*e) ? e +  : 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, );

     }

#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 ###\n");

     for (;;);

}

 .......

后面是modem的配置 不用管