/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函數
_armboot_start地址為多少？？
/*
*
* 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 應該是關于網卡的定義
#include
"
../drivers/lan91c96.h
"
#endif
DECLARE_GLOBAL_DATA_PTR
//
聲明全局數據指針
#if
(CONFIG_COMMANDS & CFG_CMD_NAND)
void
nand_init (
void
); 聲明這個方法
#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 如果沒有定義，CONFIG_IDENT_STRING就定義為空
#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網卡，則聲明下面的函數。好像是獲取網址的意思
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用于用戶程序進行分配內存
*/
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) 內存分配初始函數。
{
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);
真正實現內存分配的函數。分配了一個CFG_MALLOC_LEN大小的內存空間
}
void
*
sbrk (ptrdiff_t increment) 所分配內存區的brk指針調整。
{
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
) 一些顯示函數。顯示IRQ_STACK_START等的地址
_armboot_start, _bss_start, _bss_end 這些值
{
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
) 顯示內存的配置，打印出DRAM的大小
{
int
i;
#ifdef DEBUG
puts (
"
RAM Configuration:\n
"
);
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,
"
\n
"
);
}
#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,
"
\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 */
/*
初始化一個串行口作為控制臺，同時進行一些硬件測試
* 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.
*/
不存在一個common 即通用的初始化序列來為所有的開發板及結構進行初始化。因為不同的體系結構差別還是比較大的。
/*
* 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".
*/
通過接受一個指向全局數據的指針作為唯一的參數。
typedef
int
(init_fnc_t) (
void
);
int
print_cpuinfo (
void
);
/*
test-only
*/
init_fnc_t
*init_sequence[] =
{定義一個初始化的整型指針數組
cpu_init,
/*
basic cpu dependent setup
*/
/cpu/arm920t/
cpu.c
這個函數在cpu.c函數中定義了
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) 顯示cpu的信息
print_cpuinfo,
/*
display cpu info (and speed)
*/
#endif
#if
defined(CONFIG_DISPLAY_BOARDINFO) 顯示板的信息
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;定義一個雙重整型指針。
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為0x33f80000，CFG_MALLOC_LEN是堆大小加環境數據區大小，在smdk2410.h中有定義
#define
CFG_MALLOC_LEN (CFG_ENV_SIZE + 128*1024) CFG_ENV_SIZE為64K，所以共192K
/*
compiler optimization barrier needed for GCC >= 3.4
*/
__asm__ __volatile__(
""
: : :
"
memory
"
);
memset ((
void
*)gd,
0
,
sizeof
(gd_t));獲得一個gd指針，給全局數據變量gd分配內存
gd
->bd = (bd_t*)((
char
*)gd -
sizeof
(bd_t));
memset (gd
->bd,
0
,
sizeof
(bd_t));給板子數據變量分配內存空間
monitor_flash_len
= _bss_start -
_armboot_start;取整個代碼區Uboot的長度
順序執行init_sequence數組中的初始化函數
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
*/
從其實現上來看，好像只是配置nor flash
size
=
flash_init ();
display_flash_config (size);顯示flash的信息
#endif
/* CFG_NO_FLASH */
#ifdef CONFIG_VFD 定義顯示類型
# 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
);按頁對齊的方式保留顯存
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大小空間
mem_malloc_init (_armboot_start
-
CFG_MALLOC_LEN);
#if
(CONFIG_COMMANDS & CFG_CMD_NAND)
初始化nandflash,這是在nandflash啟動的s3c2410移植Uboot的關鍵，根據flash時序編寫函數即可。首先要在include
/configs/
smdk2410.h中打開CFG_CMD_NAND命令
puts (
"
NAND:
"
);
nand_init();
/*
go init the NAND
*/
,這個函數在前面被聲明過，現在就可以直接使用了/board/smdk2410/
smdk2410.c中沒有定義這個函數，需要添加
#endif
#ifdef CONFIG_HAS_DATAFLASH
AT91F_DataflashInit();
dataflash_print_info();
#endif
/*
initialize environment
*/
env_relocate ();初始化環境參數
#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;
}獲取網卡地址
#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.
*/
調用相應驅動函數對硬件設備進行初始化
#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 ();開中斷
/*
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
(;;);
}
.......
后面是modem的配置 不用管
?
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