分类： LINUX
2014-11-25 16:25:04
原文地址：uboot之board.c源码分析 作者：tangcong29
/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
#include
#include
#include
#include
#include
#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 ("\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
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:\n");
for(i=0; i
printf ("Bank #%d: %08lx ", i, gd->bd->bi_dram[i].start);
print_size (gd->bd->bi_dram[i].size, "\n");
}
#else
ulong size = 0;
for (i=0; i
size += gd->bd->bi_dram[i].size;
}
puts("DRAM: ");
print_size(size, "\n");
#endif
return (0);
}
#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 ((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 ###\n");
for (;;);
}
