uboot启动流程webee210启动第二阶段
又重新回到原点了，但是此时运行的环境是sdram中，好再次分析.
前面的都是相同的，但是在lowlevel_init中会有不同。
/* when we already run in ram, we don't need to relocate U-Boot.
* and actually, memory controller must be configured before U-Boot
* is running in ram.
*/
ldr r0, =0x00ffffff
bic r1, pc, r0 /* r0 <- current base addr of code */
ldr r2, _TEXT_BASE /* r1 <- original base addr in ram */
bic r2, r2, r0 /* r0 <- current base addr of code */
cmp r1, r2 /* compare r0, r1 */
beq 1f /* r0 == r1 then skip sdram init */
/* init system clock */
bl system_clock_init
/* Memory initialize */
bl mem_ctrl_asm_init
1:
/* for UART */
bl uart_asm_init
bl tzpc_init接着回到调用函数的地方。start.s中：
/* Set stackpointer in internal RAM to call board_init_f */
call_board_init_f:
ldr sp, =(CONFIG_SYS_INIT_SP_ADDR)
bic sp, sp, #7 /* 8-byte alignment for ABI compliance */
ldr r0,=0x00000000
#if defined(CONFIG_WEBEE210) || defined(CONFIG_MINI210)
adr r4, _start
ldr r5,_TEXT_BASE
cmp r5,r4
beq board_init_in_ramboard_init_in_ram:
bl board_init_fbd_t *bd;
init_fnc_t **init_fnc_ptr;
gd_t *id;
ulong addr, addr_sp;
/* Pointer is writable since we allocated a register for it */
gd = (gd_t *) ((CONFIG_SYS_INIT_SP_ADDR) & ~0x07); //gd webee 210 上的地址是
// gd = (gd_t *) ((CONFIG_SYS_INIT_SP_ADDR) & ~0x07);
/* compiler optimization barrier needed for GCC >= 3.4 */
__asm__ __volatile__("": : :"memory");
memset((void *)gd, 0, sizeof(gd_t)); //清0
gd->mon_len = _bss_end_ofs; //uboot的长度,bss段的结束地址
for (init_fnc_ptr = init_sequence; *init_fnc_ptr; ++init_fnc_ptr) { //初始化函数指针
if ((*init_fnc_ptr)() != 0) {
hang ();
}
}其中init_sequence定义如下：
init_fnc_t *init_sequence[] = {
#if defined(CONFIG_ARCH_CPU_INIT) // 有定义 初始化和CPU相关的ARCH
arch_cpu_init, /* basic arch cpu dependent setup */
#endif
#if defined(CONFIG_BOARD_EARLY_INIT_F) //未定义
board_early_init_f,
#endif
timer_init, /* initialize timer */
#ifdef CONFIG_FSL_ESDHC //未定义
get_clocks,
#endif
env_init, /* initialize environment */
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)
print_cpuinfo, /* display cpu info (and speed) */
#endif
#if defined(CONFIG_DISPLAY_BOARDINFO)
checkboard, /* display board info */
#endif
#if defined(CONFIG_HARD_I2C) || defined(CONFIG_SOFT_I2C) //未定义
init_func_i2c,
#endif
dram_init, /* configure available RAM banks */
NULL,
};@1：arch_cpu_init:
#ifdef CONFIG_ARCH_CPU_INIT
int arch_cpu_init(void)
{
s5p_set_cpu_id();
return 0;
}
#endif@2：
int timer_init(void)
{
/* PWM Timer 4 */
pwm_init(4, MUX_DIV_2, 0);
pwm_config(4, 0, 0);
pwm_enable(4);
return 0;
}初始化了pwm4的定时器，具体细节不讲了。
@3：env_init
int env_init(void)
{
//carl_Wang add
#if defined(ENV_IS_EMBEDDED) || defined(CONFIG_NAND_ENV_DST)
int crc1_ok = 0, crc2_ok = 0;
env_t *tmp_env1;
#ifdef CONFIG_ENV_OFFSET_REDUND
env_t *tmp_env2;
tmp_env2 = (env_t *)((ulong)env_ptr + CONFIG_ENV_SIZE);
crc2_ok = (crc32(0, tmp_env2->data, ENV_SIZE) == tmp_env2->crc);
#endif
tmp_env1 = env_ptr;
crc1_ok = (crc32(0, tmp_env1->data, ENV_SIZE) == tmp_env1->crc);
if (!crc1_ok && !crc2_ok) {
gd->env_addr = 0;
gd->env_valid = 0;
return 0;
} else if (crc1_ok && !crc2_ok) {
gd->env_valid = 1;
}
#ifdef CONFIG_ENV_OFFSET_REDUND
else if (!crc1_ok && crc2_ok) {
gd->env_valid = 2;
} else {
/* both ok - check serial */
if(tmp_env1->flags == 255 && tmp_env2->flags == 0)
gd->env_valid = 2;
else if(tmp_env2->flags == 255 && tmp_env1->flags == 0)
gd->env_valid = 1;
else if(tmp_env1->flags > tmp_env2->flags)
gd->env_valid = 1;
else if(tmp_env2->flags > tmp_env1->flags)
gd->env_valid = 2;
else /* flags are equal - almost impossible */
gd->env_valid = 1;
}
if (gd->env_valid == 2)
env_ptr = tmp_env2;
else
#endif
if (gd->env_valid == 1)
env_ptr = tmp_env1;
gd->env_addr = (ulong)env_ptr->data;
#else /* ENV_IS_EMBEDDED || CONFIG_NAND_ENV_DST */
gd->env_addr = (ulong)&default_environment[0];
gd->env_valid = 1;
#endif /* ENV_IS_EMBEDDED || CONFIG_NAND_ENV_DST */
return (0);
}
#else /* ENV_IS_EMBEDDED || CONFIG_NAND_ENV_DST */
gd->env_addr = (ulong)&default_environment[0];
gd->env_valid = 1;gd已经知道了，是一个全局的变量，gd->env_addr 赋值了默认的env 参数表，同时置位env_valid有效。好看一下这个env参数表
即gd->env_addr = (ulong)&default_environment[0];
gd->env_valid = 1;
const uchar default_environment[] = {
#ifdef CONFIG_BOOTARGS
"bootargs=" CONFIG_BOOTARGS "\0"
#endif
#ifdef CONFIG_BOOTCOMMAND
"bootcmd=" CONFIG_BOOTCOMMAND "nand read 0x30007fc0 0x100000 0x500000;bootm 0x30007fc0\0"
#endif
#ifdef CONFIG_RAMBOOTCOMMAND
"ramboot=" CONFIG_RAMBOOTCOMMAND "\0"
#endif
#ifdef CONFIG_NFSBOOTCOMMAND
"nfsboot=" CONFIG_NFSBOOTCOMMAND "\0"
#endif
#if defined(CONFIG_BOOTDELAY) && (CONFIG_BOOTDELAY >= 0)
"bootdelay=" MK_STR(CONFIG_BOOTDELAY) "\0"
#endif
#if defined(CONFIG_BAUDRATE) && (CONFIG_BAUDRATE >= 0)
"baudrate=" MK_STR(CONFIG_BAUDRATE) "\0"
#endif
#ifdef CONFIG_LOADS_ECHO
"loads_echo=" MK_STR(CONFIG_LOADS_ECHO) "\0"
#endif
#ifdef CONFIG_ETHADDR
"ethaddr=" MK_STR(CONFIG_ETHADDR) "\0"
#endif
#ifdef CONFIG_ETH1ADDR
"eth1addr=" MK_STR(CONFIG_ETH1ADDR) "\0"
#endif
#ifdef CONFIG_ETH2ADDR
"eth2addr=" MK_STR(CONFIG_ETH2ADDR) "\0"
#endif
#ifdef CONFIG_ETH3ADDR
"eth3addr=" MK_STR(CONFIG_ETH3ADDR) "\0"
#endif
#ifdef CONFIG_ETH4ADDR
"eth4addr=" MK_STR(CONFIG_ETH4ADDR) "\0"
#endif
#ifdef CONFIG_ETH5ADDR
"eth5addr=" MK_STR(CONFIG_ETH5ADDR) "\0"
#endif
#ifdef CONFIG_IPADDR
"ipaddr=" MK_STR(CONFIG_IPADDR) "\0"
#endif
#ifdef CONFIG_SERVERIP
"serverip=" MK_STR(CONFIG_SERVERIP) "\0"
#endif
#ifdef CONFIG_SYS_AUTOLOAD
"autoload=" CONFIG_SYS_AUTOLOAD "\0"
#endif
#ifdef CONFIG_PREBOOT
"preboot=" CONFIG_PREBOOT "\0"
#endif
#ifdef CONFIG_ROOTPATH
"rootpath=" MK_STR(CONFIG_ROOTPATH) "\0"
#endif
#ifdef CONFIG_GATEWAYIP
"gatewayip=" MK_STR(CONFIG_GATEWAYIP) "\0"
#endif
#ifdef CONFIG_NETMASK
"netmask=" MK_STR(CONFIG_NETMASK) "\0"
#endif
#ifdef CONFIG_HOSTNAME
"hostname=" MK_STR(CONFIG_HOSTNAME) "\0"
#endif
#ifdef CONFIG_BOOTFILE
"bootfile=" MK_STR(CONFIG_BOOTFILE) "\0"
#endif
#ifdef CONFIG_LOADADDR
"loadaddr=" MK_STR(CONFIG_LOADADDR) "\0"
#endif
#ifdef CONFIG_CLOCKS_IN_MHZ
"clocks_in_mhz=1\0"
#endif
#if defined(CONFIG_PCI_BOOTDELAY) && (CONFIG_PCI_BOOTDELAY > 0)
"pcidelay=" MK_STR(CONFIG_PCI_BOOTDELAY) "\0"
#endif
#ifdef CONFIG_EXTRA_ENV_SETTINGS
CONFIG_EXTRA_ENV_SETTINGS
#endif
"\0"
};@4：init_baudrate
初始化波特率，看一下env参数表中是否有这个命令，在 Webee210.h (include\configs) 中定义了
#define CONFIG_BAUDRATE 115200
所以gd->baudrate = 115200
static int init_baudrate(void)
{
char tmp[64]; /* long enough for environment variables */
int i = getenv_f("baudrate", tmp, sizeof(tmp));
gd->baudrate = (i > 0)
? (int) simple_strtoul(tmp, NULL, 10)
: CONFIG_BAUDRATE;
return (0);
}@5: serial_init Serial.c (common)
int serial_init (void)
{
//carl_wang
if (!(gd->flags & GD_FLG_RELOC) || !serial_current) {
struct serial_device *dev = default_serial_console ();
return dev->init ();
}
return serial_current->init ();
}struct serial_device {
char name[NAMESIZE];
int (*init) (void);
int (*uninit) (void);
void (*setbrg) (void);
int (*getc) (void);
int (*tstc) (void);
void (*putc) (const char c);
void (*puts) (const char *s);
#if CONFIG_POST & CONFIG_SYS_POST_UART
void (*loop) (int);
#endif
struct serial_device *next;
};dev = default_serial_console（）获取到了关于默认设备的实例，
__weak struct serial_device *default_serial_console(void)
{
#if defined(CONFIG_SERIAL0) //定义了串口0
return &s5p_serial0_device; //实例化
#elif defined(CONFIG_SERIAL1)
return &s5p_serial1_device;
#elif defined(CONFIG_SERIAL2)
return &s5p_serial2_device;
#elif defined(CONFIG_SERIAL3)
return &s5p_serial3_device;
#else
#error "CONFIG_SERIAL? missing."
#endif
}
/*
* Initialise the serial port with the given baudrate. The settings
* are always 8 data bits, no parity, 1 stop bit, no start bits.
*/
int serial_init_dev(const int dev_index)
{
//carl_wang add
struct s5p_uart *const uart = s5p_get_base_uart(dev_index);
/* reset and enable FIFOs, set triggers to the maximum */
writel(0, &uart->ufcon);
writel(0, &uart->umcon);
/* 8N1 */
writel(0x3, &uart->ulcon);
/* No interrupts, no DMA, pure polling */
writel(0x245, &uart->ucon);
serial_setbrg_dev(dev_index);
return 0;
}gd->have_console = 1;
/* Called before relocation - use serial functions */
int console_init_f(void)
{
gd->have_console = 1;
#ifdef CONFIG_SILENT_CONSOLE //未定义
if (getenv("silent") != NULL)
gd->flags |= GD_FLG_SILENT;
#endif
return 0;
}打印出的log如下：
U-Boot 2011.06 (Dec 15 2015 - 22:32:20) for Webee_210_V2
U-Boot code: 33E00000 -> 33E66A30 BSS: -> 33E9CAFC
static int display_banner(void)
{
printf("\n\n%s\n\n", version_string);
printf("U-Boot code: %08lX -> %08lX BSS: -> %08lX\n",
_TEXT_BASE,
_bss_start_ofs + _TEXT_BASE, _bss_end_ofs + _TEXT_BASE);
#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);
}
@8：print_cpuinfo
log出了一点信息，其中你想写的，还有是芯片的频率 。
#ifdef CONFIG_DISPLAY_CPUINFO
int print_cpuinfo(void)
{
char buf[32];
printf("\n");
printf("##############################################\n");
printf("# #\n");
printf("# i love wunana #\n");
printf("# #\n");
printf("##############################################\n\n");
//printf("CPU:\tS5P%X@%sMHz\n",
// s5p_cpu_id, strmhz(buf, get_arm_clk()));
printf("CPU:\tS5PV210@%sMHz\n",
strmhz(buf, get_arm_clk()));
return 0;
}
#endif
@9：checkboard：没有特殊的作用，还是log
#ifdef CONFIG_DISPLAY_BOARDINFO
int checkboard(void)
{
//carl_wang
printf("\nBoard: Webee_210_V2\n");
return (0);
}
#endif@10 dram_init 其实是初始化了
gd->ram_size = 512M
int dram_init(void)
{
/* Since we have discontinuous RAM configuration, just put
* bank1 here for relocation
*/
gd->ram_size = get_ram_size((long *)PHYS_SDRAM_1, PHYS_SDRAM_1_SIZE+PHYS_SDRAM_2_SIZE);
return 0;
}ok,假如中间有任何错误的化都会挂起等待。接着往下走
#if defined(CONFIG_SYS_MEM_TOP_HIDE)
/*
* Subtract specified amount of memory to hide so that it won't
* get "touched" at all by U-Boot. By fixing up gd->ram_size
* the Linux kernel should now get passed the now "corrected"
* memory size and won't touch it either. This should work
* for arch/ppc and arch/powerpc. Only Linux board ports in
* arch/powerpc with bootwrapper support, that recalculate the
* memory size from the SDRAM controller setup will have to
* get fixed.
*/
gd->ram_size -= CONFIG_SYS_MEM_TOP_HIDE;
#endif
addr = CONFIG_SYS_SDRAM_BASE + gd->ram_size;
#ifdef CONFIG_LOGBUFFER
#ifndef CONFIG_ALT_LB_ADDR
/* reserve kernel log buffer */
addr -= (LOGBUFF_RESERVE);
debug("Reserving %dk for kernel logbuffer at %08lx\n", LOGBUFF_LEN,
addr);
#endif
#endif其实就有一句话被编译到了，addr = CONFIG_SYS_SDRAM_BASE + gd->ram_size; 其中CONFIG_SYS_SDRAM_BASE 定义是 0x30000000，而ram_size是 536870912
ok 往下
#ifdef CONFIG_PRAM //未定义
/*
* reserve protected RAM
*/
i = getenv_r("pram", (char *)tmp, sizeof(tmp));
reg = (i > 0) ? simple_strtoul((const char *)tmp, NULL, 10) :
CONFIG_PRAM;
addr -= (reg << 10); /* size is in kB */
debug("Reserving %ldk for protected RAM at %08lx\n", reg, addr);
#endif /* CONFIG_PRAM */
#if !(defined(CONFIG_SYS_ICACHE_OFF) && defined(CONFIG_SYS_DCACHE_OFF)) //会编译到
/* reserve TLB table */
addr -= (4096 * 4);
/* round down to next 64 kB limit */
addr &= ~(0x10000 - 1);
gd->tlb_addr = addr;
printf("TLB table at: %08lx\n", addr);
#endif
/* round down to next 4 kB limit */
addr &= ~(4096 - 1);
printf("Top of RAM usable for U-Boot at: %08lx\n", addr);接着往下
#ifdef CONFIG_LCD //未定义
#ifdef CONFIG_FB_ADDR
gd->fb_base = CONFIG_FB_ADDR;
debug("Top the fb_base addr is : %08lx\n", gd->fb_base);
#else
/* reserve memory for LCD display (always full pages) */
addr = lcd_setmem(addr);
gd->fb_base = addr;
debug("Top the fb_base addr is : %08lx\n", gd->fb_base);
#endif /* CONFIG_FB_ADDR */
#endif /* CONFIG_LCD */
/*
* reserve memory for U-Boot code, data & bss
* round down to next 4 kB limit
*/
addr -= gd->mon_len;
addr &= ~(4096 - 1);
debug("Reserving %ldk for U-Boot at: %08lx\n", gd->mon_len >> 10, addr);
这个又是在为uboot预留空间，然后进行4Kb的四舍五入。
往下：
#ifndef CONFIG_SPL_BUILD //会编译到
/*
* reserve memory for malloc() arena
*/
addr_sp = addr - TOTAL_MALLOC_LEN;
debug("Reserving %dk for malloc() at: %08lx\n",
TOTAL_MALLOC_LEN >> 10, addr_sp);
/*
* (permanently) allocate a Board Info struct
* and a permanent copy of the "global" data
*/
addr_sp -= sizeof (bd_t);
bd = (bd_t *) addr_sp;
gd->bd = bd;
debug("Reserving %zu Bytes for Board Info at: %08lx\n",
sizeof (bd_t), addr_sp);
#ifdef CONFIG_MACH_TYPE
gd->bd->bi_arch_number = CONFIG_MACH_TYPE; /* board id for Linux */
#endif
addr_sp -= sizeof (gd_t);
id = (gd_t *) addr_sp;
debug("Reserving %zu Bytes for Global Data at: %08lx\n",
sizeof (gd_t), addr_sp);
/* setup stackpointer for exeptions */
gd->irq_sp = addr_sp;
#ifdef CONFIG_USE_IRQ
addr_sp -= (CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ);
debug("Reserving %zu Bytes for IRQ stack at: %08lx\n",
CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ, addr_sp);
#endif
/* leave 3 words for abort-stack */
addr_sp -= 12;
/* 8-byte alignment for ABI compliance */
addr_sp &= ~0x07;
#else
addr_sp += 128; /* leave 32 words for abort-stack */
gd->irq_sp = addr_sp;
#endif一部分预留空间给malloc使用，uboot,TLB table,board info,gd，异常退出栈（abort stack），按照webee210板子的sdram的配置，如下图：
最后还要看一下重要的数据结构gd发生了什么变化：
gd->mon_len = 0x9cd2c //uboot的长度(_start 到bss_ends）
gd->ram_size = 512M = 0x20000000 //实际的物理内存大小
gd->tlb_addr = 0x4fff0000 // TLB table 内存地址
gd->bd = bd = 0x4fe6afe0 //board info 的地址
gd->bd->bi_arch_number = 2456 //传递给linux内核的机器码
gd->irq_sp = 0x4fe6af68 //中断栈指针
此时的addr 以及addrsp 也有相对应的值了
addr = 0x4ff53000
addr_sp = 0x4fe6af58
接着往下：
#ifdef CONFIG_POST //未定义
post_bootmode_init();
post_run(NULL, POST_ROM | post_bootmode_get(0));
#endif
gd->bd->bi_baudrate = gd->baudrate;
/* Ram ist board specific, so move it to board code ... */
dram_init_banksize();
display_dram_config(); /* and display it */
gd->relocaddr = addr;
gd->start_addr_sp = addr_sp;
gd->reloc_off = addr - _TEXT_BASE;
printf("relocation Offset is: %08lx\n", gd->reloc_off);
// printf("relocaddr is: %08lx\n", gd->relocaddr);
// printf("start_addr_sp is: %08lx\n", gd->start_addr_sp);
// printf("relocation Offset is: %08lx\n", gd->reloc_off);
memcpy(id, (void *)gd, sizeof(gd_t));
relocate_code(addr_sp, id, addr);void dram_init_banksize(void)
{
gd->bd->bi_dram[0].start = PHYS_SDRAM_1;
gd->bd->bi_dram[0].size = get_ram_size((long *)PHYS_SDRAM_1, \
PHYS_SDRAM_1_SIZE);
gd->bd->bi_dram[1].start = PHYS_SDRAM_2;
gd->bd->bi_dram[1].size = get_ram_size((long *)PHYS_SDRAM_2,PHYS_SDRAM_2_SIZE);
}gd->bd->bi_dram[0].start = 0x30000000
gd->bd->bi_dram[0].size = 0x10000000
gd->bd->bi_dram[1].start = 0x40000000
gd->bd->bi_dram[1].size = 0x10000000
而后调用显示Dram的大小的函数，打印显示DRAM:512Mstatic int display_dram_config(void)
{
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");
puts(" \n\n");
#endif
return (0);
}gd->relocaddr = addr = 0x4ff53000
gd->start_addr_sp = addr_sp = 0x4fe6af58
gd->reloc_off = addr - _TEXT_BASE = 0x1c153000
memcpy(id, (void *)gd, sizeof(gd_t));
relocate_code(addr_sp, id, addr);将gd的地址拷贝到id作为参数传递给relocate_code，同时addr_sp，addr 作为参数传递给relocate_code了。
好往下走：
relocate_code是start.s 中一段代码：
/*------------------------------------------------------------------------------*/
/*
* void relocate_code (addr_sp, gd, addr_moni)
*
* This "function" does not return, instead it continues in RAM
* after relocating the monitor code.
*
*/
.globl relocate_code
relocate_code:
mov r4, r0 /* save addr_sp */
mov r5, r1 /* save addr of gd */
mov r6, r2 /* save addr of destination */
/* Set up the stack */
stack_setup:
mov sp, r4
adr r0, _start
cmp r0, r6
moveq r9, #0 /* no relocation. relocation offset(r9) = 0 */
beq clear_bss /* skip relocation */
mov r1, r6 /* r1 <- scratch for copy_loop */
ldr r3, _image_copy_end_ofs
add r2, r0, r3 /* r2 <- source end address */
copy_loop:
ldmia r0!, {r9-r10} /* copy from source address [r0] */
stmia r1!, {r9-r10} /* copy to target address [r1] */
cmp r0, r2 /* until source end address [r2] */
blo copy_loop
/////////////////////////////////////////////////////////////////////////////////
#ifndef CONFIG_SPL_BUILD
/*
* fix .rel.dyn relocations
*/
ldr r0, _TEXT_BASE /* r0 <- Text base */
sub r9, r6, r0 /* r9 <- relocation offset */
ldr r10, _dynsym_start_ofs /* r10 <- sym table ofs */
add r10, r10, r0 /* r10 <- sym table in FLASH */
ldr r2, _rel_dyn_start_ofs /* r2 <- rel dyn start ofs */
add r2, r2, r0 /* r2 <- rel dyn start in FLASH */
ldr r3, _rel_dyn_end_ofs /* r3 <- rel dyn end ofs */
add r3, r3, r0 /* r3 <- rel dyn end in FLASH */
fixloop:
ldr r0, [r2] /* r0 <- location to fix up, IN FLASH! */
add r0, r0, r9 /* r0 <- location to fix up in RAM */
ldr r1, [r2, #4]
and r7, r1, #0xff
cmp r7, #23 /* relative fixup? */
beq fixrel
cmp r7, #2 /* absolute fixup? */
beq fixabs
/* ignore unknown type of fixup */
b fixnext
fixabs:
/*
*/
/* absolute fix: set location to (offset) symbol value */
mov r1, r1, LSR #4 /* r1 <- symbol index in .dynsym */
add r1, r10, r1 /* r1 <- address of symbol in table */
ldr r1, [r1, #4] /* r1 <- symbol value */
add r1, r1, r9 /* r1 <- relocated sym addr */
b fixnext
fixrel:
/* relative fix: increase location by offset */
ldr r1, [r0]
add r1, r1, r9
fixnext:
str r1, [r0]
add r2, r2, #8 /* each rel.dyn entry is 8 bytes */
cmp r2, r3
blo fixloop
b clear_bss
_rel_dyn_start_ofs:
.word __rel_dyn_start - _start
_rel_dyn_end_ofs:
.word __rel_dyn_end - _start
_dynsym_start_ofs:
.word __dynsym_start - _start
#endif /* #ifndef CONFIG_SPL_BUILD */
/////////////////////////////////////////////////////////////////////////////////////
clear_bss:
#ifdef CONFIG_SPL_BUILD
/* No relocation for SPL */
ldr r0, =__bss_start
ldr r1, =__bss_end__
#else
ldr r0, _bss_start_ofs
ldr r1, _bss_end_ofs
mov r4, r6 /* reloc addr */
add r0, r0, r4
add r1, r1, r4
#endif
mov r2, #0x00000000 /* clear */
clbss_l:str r2, [r0] /* clear loop... */
add r0, r0, #4
cmp r0, r1
bne clbss_l
/*
* We are done. Do not return, instead branch to second part of board
* initialization, now running from RAM.
*/
jump_2_ram:
/*
* If I-cache is enabled invalidate it
*/
#ifndef CONFIG_SYS_ICACHE_OFF
mcr p15, 0, r0, c7, c5, 0 @ invalidate icache
mcr p15, 0, r0, c7, c10, 4 @ DSB
mcr p15, 0, r0, c7, c5, 4 @ ISB
#endif
ldr r0, _board_init_r_ofs
adr r1, _start
add lr, r0, r1
add lr, lr, r9
/* setup parameters for board_init_r */
mov r0, r5 /* gd_t */
mov r1, r6 /* dest_addr */
/* jump to it ... */
mov pc, lr
_board_init_r_ofs:
.word board_init_r - _start
这部分又将内存中的数据进行了一番拷贝将uboot的运行地址迁移到了gd->relocaddr处，继续执行。在完成搬运工作之后，回跳转到board_init_r的函数中，r5，r6 作为参数传入了这个函数中。
往下：void board_init_r(gd_t *id, ulong dest_addr) 这个函数将是uboot的最后一程，完成这个将完成自己的使命转入linux了。
/*
************************************************************************
*
* This is the next part if the initialization sequence: we are now
* running from RAM and have a "normal" C environment, i. e. global
* data can be written, BSS has been cleared, the stack size in not
* that critical any more, etc.
*
************************************************************************
*/
void board_init_r(gd_t *id, ulong dest_addr)
{
char *s;
bd_t *bd;
ulong malloc_start;
#if !defined(CONFIG_SYS_NO_FLASH)
ulong flash_size;
#endif
gd = id;
bd = gd->bd;
gd->flags |= GD_FLG_RELOC; /* tell others: relocation done */
monitor_flash_len = _end_ofs;
//carl_wang add
printf("hello board_init_r \n");
printf("hello dest_addr:%x %x\n,",(int)dest_addr,id);
/* Enable caches */
enable_caches();
printf("monitor flash len: %08lX\n", monitor_flash_len);
board_init(); /* Setup chipselects */
#ifdef CONFIG_SERIAL_MULTI
serial_initialize();
#endif
printf("Now running in RAM - U-Boot at: %08lx\n", dest_addr);gd = id;
bd = gd->bd;又重新回到了以前的状态，monitor_flash_len 实际上应该是uboot（除去bss段）的长度吧（有疑问）
.globl _end_ofs
_end_ofs:
.word _end - _startgd->flags |= GD_FLG_RELOC
ENTRY(_start)
SECTIONS
{
. = 0x00000000;
. = ALIGN(4);
.text :
{
arch/arm/cpu/armv7/start.o (.text)
*(.text)
}
. = ALIGN(4);
.rodata : { *(SORT_BY_ALIGNMENT(SORT_BY_NAME(.rodata*))) }
. = ALIGN(4);
.data : {
*(.data)
}
. = ALIGN(4);
. = .;
__u_boot_cmd_start = .;
.u_boot_cmd : { *(.u_boot_cmd) }
__u_boot_cmd_end = .;
. = ALIGN(4);
__image_copy_end = .;
.rel.dyn : {
__rel_dyn_start = .;
*(.rel*)
__rel_dyn_end = .;
}
.dynsym : {
__dynsym_start = .;
*(.dynsym)
}
_end = .;
.bss __rel_dyn_start (OVERLAY) : {
__bss_start = .;
*(.bss)
. = ALIGN(4);
__bss_end__ = .;
}
/DISCARD/ : { *(.dynstr*) }
/DISCARD/ : { *(.dynamic*) }
/DISCARD/ : { *(.plt*) }
/DISCARD/ : { *(.interp*) }
/DISCARD/ : { *(.gnu*) }
}
@2：使能caches，不必多讲
板级初始化board_init();
int board_init(void)
{
writel(0x22222222, GPF0CON); //GPF0CON set GPF0[0:7] as HSYNC,VSYNC,VDEN,VCLK,VD[0:3]
writel(0x0, GPF0PUD); //GPF0PUD set pull-up,down disable
writel(0x22222222, GPF1CON); //set GPF1CON[7:0] as VD[11:4]
writel(0x0, GPF1PUD); //GPF1PUD set pull-up,down disable
writel(0x22222222, GPF2CON); //set GPF2CON[7:0] as VD[19:12]
writel(0x0, GPF2PUD); //GPF2PUD set pull-up,down disable
writel(0x00002222, GPF3CON); //set GPF3CON[3:0] as VD[23:20]
writel(0x0, GPF3PUD); //GPF3PUD set pull-up,down disable
//--------- S5PC110 EVT0 needs MAX drive strength---------//
writel(0xffffffff, GPF0DRV); //set GPF0DRV drive strength max by WJ.KIM(09.07.17)
writel(0xffffffff, GPF1DRV); //set GPF1DRV drive strength max by WJ.KIM(09.07.17)
writel(0xffffffff, GPF2DRV); //set GPF2DRV drive strength max by WJ.KIM(09.07.17)
writel(0x3ff, GPF3DRV); //set GPF3DRV drive strength max by WJ.KIM(09.07.17)
/* Set Initial global variables */
s5pc110_gpio = (struct s5pc110_gpio *)S5PC110_GPIO_BASE;
/***Modified by lk ***/
//smc9115_pre_init();
pwm_pre_init();
#ifdef CONFIG_DRIVER_DM9000
dm9000_pre_init();
#endif
gd->bd->bi_arch_number = CONFIG_MACH_TYPE;
gd->bd->bi_boot_params = (PHYS_SDRAM_1+0x100);
return 0;
}gd->bd->bi_arch_number = CONFIG_MACH_TYPE;
gd->bd->bi_boot_params = (PHYS_SDRAM_1+0x100);
好宏定义展开
gd->bd->bi_arch_number = 2456 ／／传入linux的机器码
gd->bd->bi_boot_params = 0x30000000 +0x100 = 0x30000100 ／／启动参数的存放地址
往下：
#ifdef CONFIG_SERIAL_MULTI
serial_initialize();
#endif
printf("Now running in RAM - U-Boot at: %08lx\n", dest_addr);
#ifdef CONFIG_LOGBUFFER ／／未定义
logbuff_init_ptrs();
#endif
#ifdef CONFIG_POST //未定义
post_output_backlog();
#endif
/* The Malloc area is immediately below the monitor copy in DRAM */
malloc_start = dest_addr - TOTAL_MALLOC_LEN;
mem_malloc_init (malloc_start, TOTAL_MALLOC_LEN);
＠１：串口的初始化 注意我们的平台是Ｓ５Ｐ，所以应该可以猜到是用哪个函数了，没错是
void serial_initialize (void)
{
#if defined(CONFIG_8xx_CONS_SMC1) || defined(CONFIG_8xx_CONS_SMC2)
serial_register (&serial_smc_device);
#endif
#if defined(CONFIG_8xx_CONS_SCC1) || defined(CONFIG_8xx_CONS_SCC2) \
|| defined(CONFIG_8xx_CONS_SCC3) || defined(CONFIG_8xx_CONS_SCC4)
serial_register (&serial_scc_device);
#endif
#if defined(CONFIG_SYS_NS16550_SERIAL)
#if defined(CONFIG_SYS_NS16550_COM1)
serial_register(&eserial1_device);
#endif
#if defined(CONFIG_SYS_NS16550_COM2)
serial_register(&eserial2_device);
#endif
#if defined(CONFIG_SYS_NS16550_COM3)
serial_register(&eserial3_device);
#endif
#if defined(CONFIG_SYS_NS16550_COM4)
serial_register(&eserial4_device);
#endif
#endif /* CONFIG_SYS_NS16550_SERIAL */
#if defined (CONFIG_FFUART)
serial_register(&serial_ffuart_device);
#endif
#if defined (CONFIG_BTUART)
serial_register(&serial_btuart_device);
#endif
#if defined (CONFIG_STUART)
serial_register(&serial_stuart_device);
#endif
#if defined(CONFIG_S3C2410)
serial_register(&s3c24xx_serial0_device);
serial_register(&s3c24xx_serial1_device);
serial_register(&s3c24xx_serial2_device);
#endif
#if defined(CONFIG_S5P) ／／有定义
serial_register(&s5p_serial0_device);
serial_register(&s5p_serial1_device);
serial_register(&s5p_serial2_device);
serial_register(&s5p_serial3_device);
#endif
#if defined(CONFIG_MPC512X)
#if defined(CONFIG_SYS_PSC1)
serial_register(&serial1_device);
#endif
#if defined(CONFIG_SYS_PSC3)
serial_register(&serial3_device);
#endif
#if defined(CONFIG_SYS_PSC4)
serial_register(&serial4_device);
#endif
#if defined(CONFIG_SYS_PSC6)
serial_register(&serial6_device);
#endif
#endif
#if defined(CONFIG_SYS_BFIN_UART)
serial_register_bfin_uart();
#endif
serial_assign (default_serial_console ()->name);
}serial_register(&s5p_serial0_device);
serial_register(&s5p_serial1_device);
serial_register(&s5p_serial2_device);
serial_register(&s5p_serial3_device);serial_assign (default_serial_console ()->name);
void serial_register(struct serial_device *dev)
{
#ifdef CONFIG_NEEDS_MANUAL_RELOC
dev->init += gd->reloc_off;
dev->setbrg += gd->reloc_off;
dev->getc += gd->reloc_off;
dev->tstc += gd->reloc_off;
dev->putc += gd->reloc_off;
dev->puts += gd->reloc_off;
#endif
dev->next = serial_devices;
serial_devices = dev;
}
serial_assign (default_serial_console ()->name);
其实是在根据所配置的串口选出当前的串口。
__weak struct serial_device *default_serial_console(void)
{
#if defined(CONFIG_SERIAL0) ／／有定义的
return &s5p_serial0_device;
#elif defined(CONFIG_SERIAL1)
return &s5p_serial1_device;
#elif defined(CONFIG_SERIAL2)
return &s5p_serial2_device;
#elif defined(CONFIG_SERIAL3)
return &s5p_serial3_device;
#else
#error "CONFIG_SERIAL? missing."
#endif
}
serial_assign 会根据ｎａｍｅ遍历整个serial_devices来决定当前的串口是哪一个，并将serial_current赋值，显然最后serial_current ＝ s5p_serial0_device。
int serial_assign (char *name)
{
struct serial_device *s;
for (s = serial_devices; s; s = s->next) {
if (strcmp (s->name, name) == 0) {
serial_current = s;
return 0;
}
}
return 1;
}mem_malloc_init就是在给ｍａｌｌｏｃ分配起始地址，空间大小等
往下：
#if !defined(CONFIG_SYS_NO_FLASH) ／／ CONFIG_SYS_NO_FLASH有定义
puts("Flash: ");
flash_size = flash_init();
if (flash_size > 0) {
# ifdef CONFIG_SYS_FLASH_CHECKSUM
print_size(flash_size, "");
/*
* Compute and print flash CRC if flashchecksum is set to 'y'
*
* NOTE: Maybe we should add some WATCHDOG_RESET()? XXX
*/
s = getenv("flashchecksum");
if (s && (*s == 'y')) {
printf(" CRC: %08X", crc32(0,
(const unsigned char *) CONFIG_SYS_FLASH_BASE,
flash_size));
}
putc('\n');
# else /* !CONFIG_SYS_FLASH_CHECKSUM */
print_size(flash_size, "\n");
# endif /* CONFIG_SYS_FLASH_CHECKSUM */
} else {
puts(failed);
hang();
}
#endif
#if defined(CONFIG_CMD_NAND)
puts("NAND: ");
nand_init();
#endif
#if defined(CONFIG_CMD_ONENAND)
onenand_init();
#endif
#ifdef CONFIG_GENERIC_MMC
puts("MMC: ");
mmc_initialize(bd);
#endif
#ifdef CONFIG_HAS_DATAFLASH
AT91F_DataflashInit();
dataflash_print_info();
#endifnand_init(); mmc_initialize(bd);nand以及ｍｍｃ的初始化应该是标配的，ｕｂｏｏｔ的自带的，不在详细的讲解。
接着往下：
/* initialize environment */
env_relocate();
#if defined(CONFIG_CMD_PCI) || defined(CONFIG_PCI) ／／未定义
arm_pci_init();
#endif
/* IP Address */
gd->bd->bi_ip_addr = getenv_IPaddr("ipaddr");
stdio_init(); /* get the devices list going. */
printf("carl_wang->nimei@1\r\n");
jumptable_init();
#if defined(CONFIG_API) //未定义
/* Initialize API */
api_init();
#endif
//carl_wang fix
console_init_r(); /* fully init console as a device */
printf("carl_wang->nimei@2\r\n");
#if defined(CONFIG_ARCH_MISC_INIT) //未定义
/* miscellaneous arch dependent initialisations */
arch_misc_init();
#endif
#if defined(CONFIG_MISC_INIT_R) //未定义
/* miscellaneous platform dependent initialisations */
misc_init_r();
#endif
/* set up exceptions */
interrupt_init(); //设置中断
/* enable exceptions */
enable_interrupts(); //使能中断 由于我们并未使用中断，所以为空函数@1 :设置ｅｎｖ表
env_relocate();
void env_relocate (void)
{
#if defined(CONFIG_NEEDS_MANUAL_RELOC)
extern void env_reloc(void);
env_reloc();
#endif
if (gd->env_valid == 0) {
#if defined(CONFIG_ENV_IS_NOWHERE) /* Environment not changable */
set_default_env(NULL);
#else
show_boot_progress (-60);
set_default_env("!bad CRC");
#endif
} else {
env_relocate_spec ();
}
}env_valid 在之前已经设置为１了，显然走的是env_relocate_spec。
void env_relocate_spec (void)
{
printf("env_relocate_spec\n");
#if !defined(ENV_IS_EMBEDDED)
int ret;
char buf[CONFIG_ENV_SIZE];
#if defined(CONFIG_ENV_OFFSET_OOB)
ret = get_nand_env_oob(&nand_info[0], &nand_env_oob_offset);
/*
* If unable to read environment offset from NAND OOB then fall through
* to the normal environment reading code below
*/
if (!ret) {
printf("Found Environment offset in OOB..\n");
} else {
set_default_env("!no env offset in OOB");
return;
}
#endif
//ret = readenv(CONFIG_ENV_OFFSET, (u_char *)buf);
//////////////////////////////////////////////////
ret = readenv(0x15000000, (u_char *)buf);
/////////////////////////////////////////////////
if (ret) {
printf("carl_Wang readenv fail\n");
set_default_env("!readenv() failed");
return;
}
env_import(buf, 1);
#endif /* ! ENV_IS_EMBEDDED */
}这个ｅｎｖ是存储在ｎａｎｄ中的，首先会读取ｎａｎｄｆｌａｓｈ上的是否存在ｅｎｖ，假如存在的话则退出，假如不存在的话会设置默认的ｅｎｖ的环境。注意CONFIG_ENV_SIZE的大小是１６ＫＢ，读取到ｂｕｆ中，0x15000000是ｎａｎｄｆｌａｓｈ存储ｅｎｖ的起始地址，大小是１６ＫＢ
分为两种情况：
＠１已经存在ｅｎｖ
读取ｅｎｖ到ｂｕｆ中直接调用env_import(buf, 1);env_import(buf, 1)的作用是将ｅｎｖ导入到env_htab中去
/*
* Check if CRC is valid and (if yes) import the environment.
* Note that "buf" may or may not be aligned.
*/
int env_import(const char *buf, int check)
{
env_t *ep = (env_t *)buf;
if (check) {
uint32_t crc;
memcpy(&crc, &ep->crc, sizeof(crc));
if (crc32(0, ep->data, ENV_SIZE) != crc) {
set_default_env("!bad CRC");
return 0;
}
}
if (himport_r(&env_htab, (char *)ep->data, ENV_SIZE, '\0', 0)) {
gd->flags |= GD_FLG_ENV_READY;
return 1;
}
error("Cannot import environment: errno = %d\n", errno);
set_default_env("!import failed");
return 0;
}
＠２不存在ｅｎｖ或者ｅｎｖ不对
写入默认的ｅｎｖ导入到ｅｎｖ的ｈａｓｈｔａｂｌｅ中即env_htab中去，然后返回
默认的ｅｎｖ是default_environment
void set_default_env(const char *s)
{
if (sizeof(default_environment) > ENV_SIZE) {
puts("*** Error - default environment is too large\n\n");
return;
}
if (s) {
if (*s == '!') {
printf("*** Warning - %s, "
"using default environment\n\n",
s+1);
} else {
puts(s);
}
} else {
puts("Using default environment\n\n");
}
if (himport_r(&env_htab, (char *)default_environment,
sizeof(default_environment), '\0', 0) == 0) {
error("Environment import failed: errno = %d\n", errno);
}
gd->flags |= GD_FLG_ENV_READY;
}这二者的结果都是要将ｅｎｖ导入到env_htab中去，然后将
gd->flags |= GD_FLG_ENV_READY;
以后所有和ｅｎｖ相关的操作都要从env_htab从去获取或者写入
好的往下：
/* IP Address */
gd->bd->bi_ip_addr = getenv_IPaddr("ipaddr");获得ＩＰ地址，ｉｐ地址从env_htab中获取，但是并非是实际的ｉｐ地址，而是经过一定的算法得到的。具体算法如下：
IPaddr_t string_to_ip(const char *s)
{
IPaddr_t addr;
char *e;
int i;
if (s == NULL)
return(0);
printf("carl_Wang->ip:%s\n",s);
for (addr=0, i=0; i<4; ++i) {
ulong val = s ? simple_strtoul(s, &e, 10) : 0;
addr <<= 8;
addr |= (val & 0xFF);
if (s) {
s = (*e) ? e+1 : e;
}
}
return (htonl(addr));
}
接下来是比较重要的部分：
stdio_init();
nt stdio_init (void)
{
#if defined(CONFIG_NEEDS_MANUAL_RELOC) //未定义
/* already relocated for current ARM implementation */
ulong relocation_offset = gd->reloc_off;
int i;
/* relocate device name pointers */
for (i = 0; i < (sizeof (stdio_names) / sizeof (char *)); ++i) {
stdio_names[i] = (char *) (((ulong) stdio_names[i]) +
relocation_offset);
}
#endif /* CONFIG_NEEDS_MANUAL_RELOC */
/* Initialize the list */
INIT_LIST_HEAD(&(devs.list));
#ifdef CONFIG_ARM_DCC_MULTI //未定义
drv_arm_dcc_init ();
#endif
#if defined(CONFIG_HARD_I2C) || defined(CONFIG_SOFT_I2C) //未定义
i2c_init (CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
#endif
#ifdef CONFIG_LCD //未定义
drv_lcd_init ();
#endif
#if defined(CONFIG_VIDEO) || defined(CONFIG_CFB_CONSOLE) //有定义
drv_video_init ();
#endif
#ifdef CONFIG_KEYBOARD //未定义
drv_keyboard_init ();
#endif
#ifdef CONFIG_LOGBUFFER //未定义
drv_logbuff_init ();
#endif
drv_system_init ();
#ifdef CONFIG_SERIAL_MULTI
serial_stdio_init ();
#endif
#ifdef CONFIG_USB_TTY //未定义
drv_usbtty_init ();
#endif
#ifdef CONFIG_NETCONSOLE //未定义
drv_nc_init ();
#endif
#ifdef CONFIG_JTAG_CONSOLE //未定义
drv_jtag_console_init ();
#endif
return (0);
}
＠２：drv_video_init 真正的video 初始化
int drv_video_init(void)
{
int skip_dev_init;
struct stdio_dev console_dev;
/* Check if video initialization should be skipped */
if (board_video_skip()) //空函数
return 0;
/* Init video chip - returns with framebuffer cleared */
skip_dev_init = (video_init() == -1); //真正初始化ｖｉｄｅｏ的函数
#if !defined(CONFIG_VGA_AS_SINGLE_DEVICE)
debug("KBD: Keyboard init ...\n");
skip_dev_init |= (VIDEO_KBD_INIT_FCT == -1);
#endif
if (skip_dev_init)
return 0;
/* Init vga device */
memset(&console_dev, 0, sizeof(console_dev));
strcpy(console_dev.name, "vga");
console_dev.ext = DEV_EXT_VIDEO; /* Video extensions */
console_dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_SYSTEM;
console_dev.putc = video_putc; /* 'putc' function */
console_dev.puts = video_puts; /* 'puts' function */
console_dev.tstc = NULL; /* 'tstc' function */
console_dev.getc = NULL; /* 'getc' function */
#if !defined(CONFIG_VGA_AS_SINGLE_DEVICE)
/* Also init console device */
console_dev.flags |= DEV_FLAGS_INPUT;
console_dev.tstc = VIDEO_TSTC_FCT; /* 'tstc' function */
console_dev.getc = VIDEO_GETC_FCT; /* 'getc' function */
#endif /* CONFIG_VGA_AS_SINGLE_DEVICE */
if (stdio_register(&console_dev) != 0)
return 0;
/* Return success */
return 1;
}
static int video_init(void)
{
unsigned char color8;
pGD = video_hw_init();
if (pGD == NULL)
return -1;
video_fb_address = (void *) VIDEO_FB_ADRS;
#ifdef CONFIG_VIDEO_HW_CURSOR
video_init_hw_cursor(VIDEO_FONT_WIDTH, VIDEO_FONT_HEIGHT);
#endif
/* Init drawing pats */
switch (VIDEO_DATA_FORMAT) {
case GDF__8BIT_INDEX:
video_set_lut(0x01, CONSOLE_FG_COL, CONSOLE_FG_COL,
CONSOLE_FG_COL);
video_set_lut(0x00, CONSOLE_BG_COL, CONSOLE_BG_COL,
CONSOLE_BG_COL);
fgx = 0x01010101;
bgx = 0x00000000;
break;
case GDF__8BIT_332RGB:
color8 = ((CONSOLE_FG_COL & 0xe0) |
((CONSOLE_FG_COL >> 3) & 0x1c) |
CONSOLE_FG_COL >> 6);
fgx = (color8 << 24) | (color8 << 16) | (color8 << 8) |
color8;
color8 = ((CONSOLE_BG_COL & 0xe0) |
((CONSOLE_BG_COL >> 3) & 0x1c) |
CONSOLE_BG_COL >> 6);
bgx = (color8 << 24) | (color8 << 16) | (color8 << 8) |
color8;
break;
case GDF_15BIT_555RGB:
fgx = (((CONSOLE_FG_COL >> 3) << 26) |
((CONSOLE_FG_COL >> 3) << 21) |
((CONSOLE_FG_COL >> 3) << 16) |
((CONSOLE_FG_COL >> 3) << 10) |
((CONSOLE_FG_COL >> 3) << 5) |
(CONSOLE_FG_COL >> 3));
bgx = (((CONSOLE_BG_COL >> 3) << 26) |
((CONSOLE_BG_COL >> 3) << 21) |
((CONSOLE_BG_COL >> 3) << 16) |
((CONSOLE_BG_COL >> 3) << 10) |
((CONSOLE_BG_COL >> 3) << 5) |
(CONSOLE_BG_COL >> 3));
break;
case GDF_16BIT_565RGB:
fgx = (((CONSOLE_FG_COL >> 3) << 27) |
((CONSOLE_FG_COL >> 2) << 21) |
((CONSOLE_FG_COL >> 3) << 16) |
((CONSOLE_FG_COL >> 3) << 11) |
((CONSOLE_FG_COL >> 2) << 5) |
(CONSOLE_FG_COL >> 3));
bgx = (((CONSOLE_BG_COL >> 3) << 27) |
((CONSOLE_BG_COL >> 2) << 21) |
((CONSOLE_BG_COL >> 3) << 16) |
((CONSOLE_BG_COL >> 3) << 11) |
((CONSOLE_BG_COL >> 2) << 5) |
(CONSOLE_BG_COL >> 3));
break;
case GDF_32BIT_X888RGB:
fgx = (CONSOLE_FG_COL << 16) |
(CONSOLE_FG_COL << 8) |
CONSOLE_FG_COL;
bgx = (CONSOLE_BG_COL << 16) |
(CONSOLE_BG_COL << 8) |
CONSOLE_BG_COL;
break;
case GDF_24BIT_888RGB:
fgx = (CONSOLE_FG_COL << 24) |
(CONSOLE_FG_COL << 16) |
(CONSOLE_FG_COL << 8) |
CONSOLE_FG_COL;
bgx = (CONSOLE_BG_COL << 24) |
(CONSOLE_BG_COL << 16) |
(CONSOLE_BG_COL << 8) |
CONSOLE_BG_COL;
break;
}
eorx = fgx ^ bgx;
#ifdef CONFIG_VIDEO_LOGO //有定义
/* Plot the logo and get start point of console */
printf("Video: Drawing the logo ...\n");
video_console_address = video_logo();
#else
video_console_address = video_fb_address;
#endif
/* Initialize the console */
console_col = 0;
console_row = 0;
return 0;
}＠２：video_fb_address是ＬＣＤ ｆｒａｍｅｂｕｆ的初始写地址。然后根据具体使用的位数来确定ｆｇｘ以及ｂｇｘ，具体的我也不清楚了。
＠３：不过重要的是怎么ｄｒａｗｌｏｇｏ：
video_console_address = video_logo();
static void *video_logo(void)
{
char info[128];
int space, len, y_off = 0;
#ifdef CONFIG_SPLASH_SCREEN //有定义
char *s;
ulong addr;
s = getenv("splashimage"); //env 中并没有
if (s != NULL) {
int x = 0, y = 0;
addr = simple_strtoul(s, NULL, 16);
#ifdef CONFIG_SPLASH_SCREEN_ALIGN
s = getenv("splashpos");
if (s != NULL) {
if (s[0] == 'm')
x = BMP_ALIGN_CENTER;
else
x = simple_strtol(s, NULL, 0);
s = strchr(s + 1, ',');
if (s != NULL) {
if (s[1] == 'm')
y = BMP_ALIGN_CENTER;
else
y = simple_strtol(s + 1, NULL, 0);
}
}
#endif /* CONFIG_SPLASH_SCREEN_ALIGN */
if (video_display_bitmap(addr, x, y) == 0) {
video_logo_height = 0;
return ((void *) (video_fb_address));
}
}
#endif /* CONFIG_SPLASH_SCREEN */
/*change the plot of logo*/
logo_plot(video_fb_address, VIDEO_COLS, VIDEO_LOGO_X, VIDEO_LOGO_Y);
#ifdef DEBUG_CFB_CONSOLE_LCD
sprintf(info, " %s"," " );
#else
sprintf(info, " %s", version_string);
#endif
space = (VIDEO_LINE_LEN / 2 - VIDEO_INFO_X) / VIDEO_FONT_WIDTH;
len = strlen(info);
if (len > space) {
video_drawchars(VIDEO_INFO_X, VIDEO_INFO_Y,
(uchar *) info, space);
video_drawchars(VIDEO_INFO_X + VIDEO_FONT_WIDTH,
VIDEO_INFO_Y + VIDEO_FONT_HEIGHT,
(uchar *) info + space, len - space);
y_off = 1;
} else
video_drawstring(VIDEO_INFO_X, VIDEO_INFO_Y, (uchar *) info);
#ifdef CONFIG_CONSOLE_EXTRA_INFO
{
int i, n =
((video_logo_height -
VIDEO_FONT_HEIGHT) / VIDEO_FONT_HEIGHT);
for (i = 1; i < n; i++) {
video_get_info_str(i, info);
if (!*info)
continue;
len = strlen(info);
if (len > space) {
video_drawchars(VIDEO_INFO_X,
VIDEO_INFO_Y +
(i + y_off) *
VIDEO_FONT_HEIGHT,
(uchar *) info, space);
y_off++;
video_drawchars(VIDEO_INFO_X +
VIDEO_FONT_WIDTH,
VIDEO_INFO_Y +
(i + y_off) *
VIDEO_FONT_HEIGHT,
(uchar *) info + space,
len - space);
} else {
video_drawstring(VIDEO_INFO_X,
VIDEO_INFO_Y +
(i + y_off) *
VIDEO_FONT_HEIGHT,
(uchar *) info);
}
}
}
#endif
return (video_fb_address + video_logo_height * VIDEO_LINE_LEN);
}
#endif＠１：画图：logo_plot 整体思路就是将对应的ｌｏｇｏ变化成１６进制的数组，这里对应的数组是bmp_logo_palette，那么如何将图转变成数组好接下来讲具体步骤：
#ifdef CONFIG_VIDEO_LOGO
void logo_plot(void *screen, int width, int x, int y)
{
int xcount, i;
int skip = (width - VIDEO_LOGO_WIDTH) * VIDEO_PIXEL_SIZE;
int ycount = video_logo_height;
unsigned char r, g, b, *logo_red, *logo_blue, *logo_green;
unsigned char *source;
unsigned char *dest = (unsigned char *) screen +
((y * width * VIDEO_PIXEL_SIZE) + x * VIDEO_PIXEL_SIZE);
printf("carl_wang->logo_plot\n");
#ifdef CONFIG_VIDEO_BMP_LOGO
source = bmp_logo_bitmap;
/* Allocate temporary space for computing colormap */
logo_red = malloc(BMP_LOGO_COLORS);
logo_green = malloc(BMP_LOGO_COLORS);
logo_blue = malloc(BMP_LOGO_COLORS);
/* Compute color map */
for (i = 0; i < VIDEO_LOGO_COLORS; i++) {
logo_red[i] = (bmp_logo_palette[i] & 0x0f00) >> 4;
logo_green[i] = (bmp_logo_palette[i] & 0x00f0);
logo_blue[i] = (bmp_logo_palette[i] & 0x000f) << 4;
}
#else
source = linux_logo;
logo_red = linux_logo_red;
logo_green = linux_logo_green;
logo_blue = linux_logo_blue;
#endif
if (VIDEO_DATA_FORMAT == GDF__8BIT_INDEX) {
for (i = 0; i < VIDEO_LOGO_COLORS; i++) {
video_set_lut(i + VIDEO_LOGO_LUT_OFFSET,
logo_red[i], logo_green[i],
logo_blue[i]);
}
}
while (ycount--) {
#if defined(VIDEO_FB_16BPP_PIXEL_SWAP)
int xpos = x;
#endif
xcount = VIDEO_LOGO_WIDTH;
while (xcount--) {
r = logo_red[*source - VIDEO_LOGO_LUT_OFFSET];
g = logo_green[*source - VIDEO_LOGO_LUT_OFFSET];
b = logo_blue[*source - VIDEO_LOGO_LUT_OFFSET];
switch (VIDEO_DATA_FORMAT) {
case GDF__8BIT_INDEX:
*dest = *source;
break;
case GDF__8BIT_332RGB:
*dest = ((r >> 5) << 5) |
((g >> 5) << 2) |
(b >> 6);
break;
case GDF_15BIT_555RGB:
#if defined(VIDEO_FB_16BPP_PIXEL_SWAP)
fill_555rgb_pswap(dest, xpos++, r, g, b);
#else
*(unsigned short *) dest =
SWAP16((unsigned short) (
((r >> 3) << 10) |
((g >> 3) << 5) |
(b >> 3)));
#endif
break;
case GDF_16BIT_565RGB:
*(unsigned short *) dest =
SWAP16((unsigned short) (
((r >> 3) << 11) |
((g >> 2) << 5) |
(b >> 3)));
break;
case GDF_32BIT_X888RGB:
*(unsigned long *) dest =
SWAP32((unsigned long) (
(r << 16) |
(g << 8) |
b));
break;
case GDF_24BIT_888RGB:
#ifdef VIDEO_FB_LITTLE_ENDIAN
dest[0] = b;
dest[1] = g;
dest[2] = r;
#else
dest[0] = r;
dest[1] = g;
dest[2] = b;
#endif
break;
}
source++;
dest += VIDEO_PIXEL_SIZE;
}
dest += skip;
}
#ifdef CONFIG_VIDEO_BMP_LOGO
free(logo_red);
free(logo_green);
free(logo_blue);
#endif
}#!/bin/sh
#install Netpbm first
jpegtopnm $1 | ppmquant 31 | ppmtobmp -bpp 8 > $2＠２：转成bmp图之后将其拷贝到tools下，然后有一个bmp_logo的可执行文件，其对应的代码是bmp_logo.c,对应的指令是./bmp_logo ./logos/webee210.bmp > 1.txt，其生成的数组就在１.txt中了，将其全部替换写入Bmp_logo.h (include)
＠３ｏｋ，大功告成，看看你的图片修改成功没。
＠４ 其实我还是遇到了一些不顺心的事就是我的图片很大，但是显示的时候发现照片数据显示不完整，所以百度了一番，发现是bmp_logo.c的问题，uboot是轻量化的启动，支持较小图片的显示，不过我还是找到了，可以参照http://blog.csdn.net/lutao614/article/details/17507951中说的，进行修改，但是我的图片好像是实在太大了，虽然可以显示全了，但是发现图片有移位的现象，像是生成的bmp数组越界之后重新来过了。这个我就不再考虑了。假如哪天显示全了我再重新写个博客。
＠５最后返回了新的ｆｒａｍｅｂｕｆ的地址
返回到drv_video_init的函数中，此时又新建了一个console_dev的实例化设备并将其填入到ｄｅｖｓ的链表中，同时初始化对应的函数指针。
/* Init vga device */
memset(&console_dev, 0, sizeof(console_dev));
strcpy(console_dev.name, "vga");
console_dev.ext = DEV_EXT_VIDEO; /* Video extensions */
console_dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_SYSTEM;
console_dev.putc = video_putc; /* 'putc' function */
console_dev.puts = video_puts; /* 'puts' function */
console_dev.tstc = NULL; /* 'tstc' function */
console_dev.getc = NULL; /* 'getc' function */
#if !defined(CONFIG_VGA_AS_SINGLE_DEVICE)
/* Also init console device */
console_dev.flags |= DEV_FLAGS_INPUT;
console_dev.tstc = VIDEO_TSTC_FCT; /* 'tstc' function */
console_dev.getc = VIDEO_GETC_FCT; /* 'getc' function */
#endif /* CONFIG_VGA_AS_SINGLE_DEVICE */
if (stdio_register(&console_dev) != 0)
return 0;
/* Return success */
return 1;好往下：
drv_system_init ();static void drv_system_init (void)
{
struct stdio_dev dev;
memset (&dev, 0, sizeof (dev));
strcpy (dev.name, "serial");
dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT | DEV_FLAGS_SYSTEM;
dev.putc = serial_putc;
dev.puts = serial_puts;
dev.getc = serial_getc;
dev.tstc = serial_tstc;
stdio_register (&dev);
#ifdef CONFIG_SYS_DEVICE_NULLDEV //未定义
memset (&dev, 0, sizeof (dev));
strcpy (dev.name, "nulldev");
dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT | DEV_FLAGS_SYSTEM;
dev.putc = nulldev_putc;
dev.puts = nulldev_puts;
dev.getc = nulldev_input;
dev.tstc = nulldev_input;
stdio_register (&dev);
#endif
}
这个函数实际上是将之前注册在serial_devices链表中的串口设备全部注册在了devs的链表中了。
void serial_stdio_init (void)
{
struct stdio_dev dev;
struct serial_device *s = serial_devices;
while (s) {
memset (&dev, 0, sizeof (dev));
strcpy (dev.name, s->name);
dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT;
dev.start = s->init;
dev.stop = s->uninit;
dev.putc = s->putc;
dev.puts = s->puts;
dev.getc = s->getc;
dev.tstc = s->tstc;
stdio_register (&dev);
s = s->next;
}
}好 stdio_init(); 已经结束了
回到Board.c (arch\arm\lib）
jumptable_init();
申请空间并初始化了一部分的常用函数额跳转表
void jumptable_init(void)
{
gd->jt = malloc(XF_MAX * sizeof(void *));
#include <_exports.h>
}
_exports.h
EXPORT_FUNC(get_version)
EXPORT_FUNC(getc)
EXPORT_FUNC(tstc)
EXPORT_FUNC(putc)
EXPORT_FUNC(puts)
EXPORT_FUNC(printf)
EXPORT_FUNC(install_hdlr)
EXPORT_FUNC(free_hdlr)
EXPORT_FUNC(malloc)
EXPORT_FUNC(free)
EXPORT_FUNC(udelay)
EXPORT_FUNC(get_timer)
EXPORT_FUNC(vprintf)
EXPORT_FUNC(do_reset)
EXPORT_FUNC(getenv)
EXPORT_FUNC(setenv)
EXPORT_FUNC(simple_strtoul)
EXPORT_FUNC(strict_strtoul)
EXPORT_FUNC(simple_strtol)
EXPORT_FUNC(strcmp)
EXPORT_FUNC(i2c_write)
EXPORT_FUNC(i2c_read)
EXPORT_FUNC(spi_init)
EXPORT_FUNC(spi_setup_slave)
EXPORT_FUNC(spi_free_slave)
EXPORT_FUNC(spi_claim_bus)
EXPORT_FUNC(spi_release_bus)
EXPORT_FUNC(spi_xfer)
console_init_r 其实是将stdin,stdout,stderr 的函数重定向了，重定向到了名为serial 的设备上。
int console_init_r(void)
{
char *stdinname, *stdoutname, *stderrname;
struct stdio_dev *inputdev = NULL, *outputdev = NULL, *errdev = NULL;
#ifdef CONFIG_SYS_CONSOLE_ENV_OVERWRITE
int i;
#endif /* CONFIG_SYS_CONSOLE_ENV_OVERWRITE */
#ifdef CONFIG_CONSOLE_MUX
int iomux_err = 0;
#endif
/* set default handlers at first */
gd->jt[XF_getc] = serial_getc;
gd->jt[XF_tstc] = serial_tstc;
gd->jt[XF_putc] = serial_putc;
gd->jt[XF_puts] = serial_puts;
gd->jt[XF_printf] = serial_printf;
/* stdin stdout and stderr are in environment */
/* scan for it */
stdinname = getenv("stdin");
stdoutname = getenv("stdout");
stderrname = getenv("stderr");
if (OVERWRITE_CONSOLE == 0) { /* if not overwritten by config switch */
inputdev = search_device(DEV_FLAGS_INPUT, stdinname);
outputdev = search_device(DEV_FLAGS_OUTPUT, stdoutname);
errdev = search_device(DEV_FLAGS_OUTPUT, stderrname);
#ifdef CONFIG_CONSOLE_MUX
iomux_err = iomux_doenv(stdin, stdinname);
iomux_err += iomux_doenv(stdout, stdoutname);
iomux_err += iomux_doenv(stderr, stderrname);
if (!iomux_err)
/* Successful, so skip all the code below. */
goto done;
#endif
}
/* if the devices are overwritten or not found, use default device */
if (inputdev == NULL) {
inputdev = search_device(DEV_FLAGS_INPUT, "serial");
}
if (outputdev == NULL) {
outputdev = search_device(DEV_FLAGS_OUTPUT, "serial");
}
if (errdev == NULL) {
errdev = search_device(DEV_FLAGS_OUTPUT, "serial");
}
/* Initializes output console first */
if (outputdev != NULL) {
/* need to set a console if not done above. */
console_doenv(stdout, outputdev);
}
if (errdev != NULL) {
/* need to set a console if not done above. */
console_doenv(stderr, errdev);
}
if (inputdev != NULL) {
/* need to set a console if not done above. */
console_doenv(stdin, inputdev);
}
#ifdef CONFIG_CONSOLE_MUX
done:
#endif
gd->flags |= GD_FLG_DEVINIT; /* device initialization completed */
stdio_print_current_devices();
#ifdef CONFIG_SYS_CONSOLE_ENV_OVERWRITE //未定义
/* set the environment variables (will overwrite previous env settings) */
for (i = 0; i < 3; i++) {
setenv(stdio_names[i], stdio_devices[i]->name);
}
#endif /* CONFIG_SYS_CONSOLE_ENV_OVERWRITE */
#if 0
/* If nothing usable installed, use only the initial console */
if ((stdio_devices[stdin] == NULL) && (stdio_devices[stdout] == NULL))
return 0;
#endif
return 0;
}#ifdef DEBUG_CFB_CONSOLE_LCD
#define DEBUG_CFB_CONSOLE
#define CONFIG_EXTRA_ENV_SETTINGS \
"stdin=serial\0" \
"stdout=vga\0" \
"stderr=serial\0" \
""
#define VIDEO_LOGO_X 180
#define VIDEO_LOGO_Y 18
#else
#define VIDEO_LOGO_X 180
#define VIDEO_LOGO_Y 120
#endif gd->jt[XF_getc] = serial_getc;
gd->jt[XF_tstc] = serial_tstc;
gd->jt[XF_putc] = serial_putc;
gd->jt[XF_puts] = serial_puts;
gd->jt[XF_printf] = serial_printf;往下了：
/* Perform network card initialisation if necessary */
#if defined(CONFIG_DRIVER_SMC91111) || defined (CONFIG_DRIVER_LAN91C96) //未定义
/* 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 */
s = getenv("loadaddr");
if (s != NULL)
load_addr = simple_strtoul(s, NULL, 16);
#if defined(CONFIG_CMD_NET) //未定义
s = getenv("bootfile");
if (s != NULL)
copy_filename(BootFile, s, sizeof(BootFile));
#endif
#ifdef BOARD_LATE_INIT
board_late_init(); //暂时不知道什么意思
#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);
puts("\n ");
puts("\n");
#if defined(CONFIG_RESET_PHY_R) //未定义
debug("Reset Ethernet PHY\n");
reset_phy();
#endif
#endif
#ifdef CONFIG_POST //未定义
post_run(NULL, POST_RAM | post_bootmode_get(0));
#endif
＠２：board_late_init();这两个幻数搞的我有点蒙圈了，希望有人指点
int board_late_init (void)
{
uint *magic = (uint*)(PHYS_SDRAM_1);
char boot_cmd[100];
if ((0x24564236 == magic[0]) && (0x20764316 == magic[1])) {
printf("carl_Wang haha\n");
sprintf(boot_cmd, "nand erase 0 40000;nand write %08x 0 40000", PHYS_SDRAM_1 + 0x8000);
magic[0] = 0;
magic[1] = 0;
printf("\nready for self-burning U-Boot image\n\n");
setenv("bootdelay", "0");
setenv("bootcmd", boot_cmd);
}
return 0;
}int eth_initialize(bd_t *bis)
{
int eth_number = 0;
eth_devices = NULL;
eth_current = NULL;
show_boot_progress (64);
#if defined(CONFIG_MII) || defined(CONFIG_CMD_MII)
miiphy_init();
#endif
#ifdef CONFIG_PHYLIB
phy_init();
#endif
/*
* If board-specific initialization exists, call it.
* If not, call a CPU-specific one
*/
if (board_eth_init != __def_eth_init) {
if (board_eth_init(bis) < 0)
printf("Board Net Initialization Failed\n");
} else if (cpu_eth_init != __def_eth_init) {
if (cpu_eth_init(bis) < 0)
printf("CPU Net Initialization Failed\n");
} else
printf("Net Initialization Skipped\n");
#if defined(CONFIG_DB64360) || defined(CONFIG_CPCI750)
mv6436x_eth_initialize(bis);
#endif
#if defined(CONFIG_DB64460) || defined(CONFIG_P3Mx)
mv6446x_eth_initialize(bis);
#endif
if (!eth_devices) {
puts ("No ethernet found.\n");
show_boot_progress (-64);
} else {
struct eth_device *dev = eth_devices;
char *ethprime = getenv ("ethprime");
show_boot_progress (65);
do {
if (eth_number)
puts (", ");
printf("%s", dev->name);
if (ethprime && strcmp (dev->name, ethprime) == 0) {
eth_current = dev;
puts (" [PRIME]");
}
if (strchr(dev->name, ' '))
puts("\nWarning: eth device name has a space!\n");
//printf("eth_number = %d\n",eth_number);
/***Modified by lk ***/
if (eth_write_hwaddr(dev, "eth", eth_number))
puts("Warning: failed to set MAC address\n");
eth_number++;
dev = dev->next;
} while(dev != eth_devices);
eth_current_changed();
putc ('\n');
}
return eth_number;
}接着往下：
#if defined(CONFIG_PRAM) || defined(CONFIG_LOGBUFFER) //未定义
/*
* Export available size of memory for Linux,
* taking into account the protected RAM at top of memory
*/
{
ulong pram;
uchar memsz[32];
#ifdef CONFIG_PRAM //未定义
char *s;
s = getenv("pram");
if (s != NULL)
pram = simple_strtoul(s, NULL, 10);
else
pram = CONFIG_PRAM;
#else
pram = 0;
#endif
#ifdef CONFIG_LOGBUFFER
#ifndef CONFIG_ALT_LB_ADDR
/* Also take the logbuffer into account (pram is in kB) */
pram += (LOGBUFF_LEN + LOGBUFF_OVERHEAD) / 1024;
#endif
#endif
sprintf((char *)memsz, "%ldk", (gd->ram_size / 1024) - pram);
setenv("mem", (char *)memsz);
}
#endif
/* main_loop() can return to retry autoboot, if so just run it again. */
for (;;) {
main_loop(); 主函数的死循环，这个就是等待用户输入指令了。
}
/* NOTREACHED - no way out of command loop except booting */
}void main_loop (void)
{
#ifndef CONFIG_SYS_HUSH_PARSER //有定义，所以不跑
static char lastcommand[CONFIG_SYS_CBSIZE] = { 0, };
int len;
int rc = 1;
int flag;
#endif
#if defined(CONFIG_BOOTDELAY) && (CONFIG_BOOTDELAY >= 0) //有定义启动延时
char *s;
int bootdelay;
#endif
#ifdef CONFIG_PREBOOT //未定义
char *p;
#endif
#ifdef CONFIG_BOOTCOUNT_LIMIT //未定义
unsigned long bootcount = 0;
unsigned long bootlimit = 0;
char *bcs;
char bcs_set[16];
#endif /* CONFIG_BOOTCOUNT_LIMIT */
#ifdef CONFIG_BOOTCOUNT_LIMIT //未定义
bootcount = bootcount_load();
bootcount++;
bootcount_store (bootcount);
sprintf (bcs_set, "%lu", bootcount);
setenv ("bootcount", bcs_set);
bcs = getenv ("bootlimit");
bootlimit = bcs ? simple_strtoul (bcs, NULL, 10) : 0;
#endif /* CONFIG_BOOTCOUNT_LIMIT */
#ifdef CONFIG_MODEM_SUPPORT .//未定义
debug ("DEBUG: main_loop: do_mdm_init=%d\n", do_mdm_init);
if (do_mdm_init) {
char *str = strdup(getenv("mdm_cmd"));
setenv ("preboot", str); /* set or delete definition */
if (str != NULL)
free (str);
mdm_init(); /* wait for modem connection */
}
#endif /* CONFIG_MODEM_SUPPORT */
#ifdef CONFIG_VERSION_VARIABLE //未定义
{
setenv ("ver", version_string); /* set version variable */
}
#endif /* CONFIG_VERSION_VARIABLE */
#ifdef CONFIG_SYS_HUSH_PARSER
u_boot_hush_start ();
#endif
#if defined(CONFIG_HUSH_INIT_VAR) //未定义
hush_init_var ();
#endif
#ifdef CONFIG_PREBOOT //未定义
if ((p = getenv ("preboot")) != NULL) {
# ifdef CONFIG_AUTOBOOT_KEYED
int prev = disable_ctrlc(1); /* disable Control C checking */
# endif
# ifndef CONFIG_SYS_HUSH_PARSER
run_command (p, 0);
# else
parse_string_outer(p, FLAG_PARSE_SEMICOLON |
FLAG_EXIT_FROM_LOOP);
# endif
# ifdef CONFIG_AUTOBOOT_KEYED
disable_ctrlc(prev); /* restore Control C checking */
# endif
}
#endif /* CONFIG_PREBOOT */
#if defined(CONFIG_UPDATE_TFTP) //未定义
update_tftp (0UL);
#endif /* CONFIG_UPDATE_TFTP */
#if defined(CONFIG_BOOTDELAY) && (CONFIG_BOOTDELAY >= 0)
s = getenv ("bootdelay");
bootdelay = s ? (int)simple_strtol(s, NULL, 10) : CONFIG_BOOTDELAY; //bootdelay = CONFIG_BOOTDELAY = 5
debug ("### main_loop entered: bootdelay=%d\n\n", bootdelay);
# ifdef CONFIG_BOOT_RETRY_TIME //未定义
init_cmd_timeout ();
# endif /* CONFIG_BOOT_RETRY_TIME */
#ifdef CONFIG_POST //未定义
if (gd->flags & GD_FLG_POSTFAIL) {
s = getenv("failbootcmd");
}
else
#endif /* CONFIG_POST */
#ifdef CONFIG_BOOTCOUNT_LIMIT //未定义
if (bootlimit && (bootcount > bootlimit)) {
printf ("Warning: Bootlimit (%u) exceeded. Using altbootcmd.\n",
(unsigned)bootlimit);
s = getenv ("altbootcmd");
}
else
#endif /* CONFIG_BOOTCOUNT_LIMIT */
s = getenv ("bootcmd"); ／／@2
debug ("### main_loop: bootcmd=\"%s\"\n", s ? s : "");
if (bootdelay >= 0 && s && !abortboot (bootdelay)) {
board_video_reset();
# ifdef CONFIG_AUTOBOOT_KEYED //未定义
int prev = disable_ctrlc(1); /* disable Control C checking */
# endif
# ifndef CONFIG_SYS_HUSH_PARSER
run_command (s, 0);
# else
printf("carl_wang->%s\n",s);
parse_string_outer(s, FLAG_PARSE_SEMICOLON |
FLAG_EXIT_FROM_LOOP);
# endif
# ifdef CONFIG_AUTOBOOT_KEYED
disable_ctrlc(prev); /* restore Control C checking */
# endif
}
printf("carl_wang->%d\n",bootdelay);
//run_command("sound",0);
run_command("menu",0);
# ifdef CONFIG_MENUKEY
if (menukey == CONFIG_MENUKEY) {
s = getenv("menucmd");
if (s) {
# ifndef CONFIG_SYS_HUSH_PARSER
run_command(s, 0);
# else
parse_string_outer(s, FLAG_PARSE_SEMICOLON |
FLAG_EXIT_FROM_LOOP);
# endif
}
}
#endif /* CONFIG_MENUKEY */
#endif /* CONFIG_BOOTDELAY */
/*
* Main Loop for Monitor Command Processing
*/
#ifdef CONFIG_SYS_HUSH_PARSER
parse_file_outer();
/* This point is never reached */
for (;;);
board_video_reset();
#else
for (;;) {
#ifdef CONFIG_BOOT_RETRY_TIME
if (rc >= 0) {
/* Saw enough of a valid command to
* restart the timeout.
*/
reset_cmd_timeout();
}
#endif
len = readline (CONFIG_SYS_PROMPT);
flag = 0; /* assume no special flags for now */
if (len > 0)
strcpy (lastcommand, console_buffer);
else if (len == 0)
flag |= CMD_FLAG_REPEAT;
#ifdef CONFIG_BOOT_RETRY_TIME
else if (len == -2) {
/* -2 means timed out, retry autoboot
*/
puts ("\nTimed out waiting for command\n");
# ifdef CONFIG_RESET_TO_RETRY
/* Reinit board to run initialization code again */
do_reset (NULL, 0, 0, NULL);
# else
return; /* retry autoboot */
# endif
}
#endif
if (len == -1)
puts ("\n");
else
rc = run_command (lastcommand, flag);
if (rc <= 0) {
/* invalid command or not repeatable, forget it */
lastcommand[0] = 0;
}
}
#endif /*CONFIG_SYS_HUSH_PARSER*/
}
＠１：u_boot_hush_start 初始化了一个top_vars全局变量。
int u_boot_hush_start(void)
{
if (top_vars == NULL) {
top_vars = malloc(sizeof(struct variables));
top_vars->name = "HUSH_VERSION";
top_vars->value = "0.01";
top_vars->next = 0;
top_vars->flg_export = 0;
top_vars->flg_read_only = 1;
#ifdef CONFIG_NEEDS_MANUAL_RELOC
u_boot_hush_reloc();
#endif
}
return 0;
}＠２：从ｅｎｖ中读取ｂｏｏｔｃｍｄ，发现有定义的，"bootcmd=" CONFIG_BOOTCOMMAND "nand read 0x30007fc0 0x100000 0x500000;bootm 0x30007fc0\0"
s = getenv ("bootcmd"); @2
debug ("### main_loop: bootcmd=\"%s\"\n", s ? s : "");
if (bootdelay >= 0 && s && !abortboot (bootdelay)) {
board_video_reset(); 那么真正的是在abortboot (bootdelay）做文章。
static inline int abortboot(int bootdelay)
{
int abort = 0;
#ifdef CONFIG_MENUPROMPT
printf(CONFIG_MENUPROMPT);
#else
printf("Hit any key to stop autoboot: %2d ", bootdelay);
#endif
#ifdef CONFIG_UBOOT_KEY
//run_command("drawstring 280 330 hit-S1-to-burn-*.img..........",0);
udelay(10000);
udelay(10000);
udelay(10000);
if(0 == check_key(0))
{
abort =1 ;
}
#endif
#if defined CONFIG_ZERO_BOOTDELAY_CHECK
/*
* Check if key already pressed
* Don't check if bootdelay < 0
*/
if (bootdelay >= 0) {
if (tstc()) { /* we got a key press */
(void) getc(); /* consume input */
puts ("\b\b\b 0");
abort = 1; /* don't auto boot */
}
}
#endif
while ((bootdelay > 0) && (!abort)) {
int i;
--bootdelay;
/* delay 100 * 10ms */
#ifdef CONFIG_UBOOT_KEY
if(0 == check_key(0))
{
abort =1 ;
}
#endif
for (i=0; !abort && i<100; ++i) {
if (tstc()) { /* we got a key press */
abort = 1; /* don't auto boot */
bootdelay = 0; /* no more delay */
#ifdef CONFIG_MENUKEY
menukey = getc();
#else
(void) getc(); /* consume input */
# endif
break;
}
udelay(10000);
}
printf("\b\b\b%2d ", bootdelay);
}
putc('\n');
#ifdef CONFIG_SILENT_CONSOLE
if (abort)
gd->flags &= ~GD_FLG_SILENT;
#endif
return abort;
}
# endif /* CONFIG_AUTOBOOT_KEYED */
#endif /* CONFIG_BOOTDELAY >= 0 */首先延时了３０ｍｓ，然后检测是否有键按下，有的话 ａｂｏｒｔ＝１；或者３０ｍｓ之后是否有终端有消息有的话，ａｂｏｒｔ ＝ １；然后跳入ｗｈｉｌｅ循环，ｗｉｈｌｅ循环中一直检测是否有串口数据。有的话直接跳出后返回ａｂｏｒｔ＝１；没有的话是ａｂｏｒｔ ＝ ０；
有两种情况：
１．倒计时完成仍然没有数据：将ｓ的启动指令传递到parse_string_outer，指令是 nand read 0x30007fc0 0x100000 0x500000;bootm 0x30007fc0，
parse_string_outer(s, FLAG_PARSE_SEMICOLON |
FLAG_EXIT_FROM_LOOP);
这个其实会传递执行两个命令，一个是将ｌｉｎｕｘ 的镜像读取到０ｘ３０００７ｆｃ０，然后从0x30007fc0启动，其中要讲一下关于ｂｏｏｔｍ的命令会干一件事情将我们之前的ｇｄ参数打包并传递到ｌｉｎｕｘ内核，内核完成解析。
int do_bootm (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
ulong iflag;
ulong load_end = 0;
int ret;
boot_os_fn *boot_fn;
#ifdef CONFIG_NEEDS_MANUAL_RELOC
static int relocated = 0;
/* relocate boot function table */
if (!relocated) {
int i;
for (i = 0; i < ARRAY_SIZE(boot_os); i++)
if (boot_os[i] != NULL)
boot_os[i] += gd->reloc_off;
relocated = 1;
}
#endif
/* determine if we have a sub command */
if (argc > 1) {
char *endp;
simple_strtoul(argv[1], &endp, 16);
/* endp pointing to NULL means that argv[1] was just a
* valid number, pass it along to the normal bootm processing
*
* If endp is ':' or '#' assume a FIT identifier so pass
* along for normal processing.
*
* Right now we assume the first arg should never be '-'
*/
if ((*endp != 0) && (*endp != ':') && (*endp != '#'))
return do_bootm_subcommand(cmdtp, flag, argc, argv);
}
if (bootm_start(cmdtp, flag, argc, argv))
return 1;
/*
* We have reached the point of no return: we are going to
* overwrite all exception vector code, so we cannot easily
* recover from any failures any more...
*/
iflag = disable_interrupts();
#if defined(CONFIG_CMD_USB)
/*
* turn off USB to prevent the host controller from writing to the
* SDRAM while Linux is booting. This could happen (at least for OHCI
* controller), because the HCCA (Host Controller Communication Area)
* lies within the SDRAM and the host controller writes continously to
* this area (as busmaster!). The HccaFrameNumber is for example
* updated every 1 ms within the HCCA structure in SDRAM! For more
* details see the OpenHCI specification.
*/
usb_stop();
#endif
ret = bootm_load_os(images.os, &load_end, 1);
if (ret < 0) {
if (ret == BOOTM_ERR_RESET)
do_reset (cmdtp, flag, argc, argv);
if (ret == BOOTM_ERR_OVERLAP) {
if (images.legacy_hdr_valid) {
if (image_get_type (&images.legacy_hdr_os_copy) == IH_TYPE_MULTI)
puts ("WARNING: legacy format multi component "
"image overwritten\n");
} else {
puts ("ERROR: new format image overwritten - "
"must RESET the board to recover\n");
show_boot_progress (-113);
do_reset (cmdtp, flag, argc, argv);
}
}
if (ret == BOOTM_ERR_UNIMPLEMENTED) {
if (iflag)
enable_interrupts();
show_boot_progress (-7);
return 1;
}
}
lmb_reserve(&images.lmb, images.os.load, (load_end - images.os.load));
if (images.os.type == IH_TYPE_STANDALONE) {
if (iflag)
enable_interrupts();
/* This may return when 'autostart' is 'no' */
bootm_start_standalone(iflag, argc, argv);
return 0;
}
show_boot_progress (8);
#ifdef CONFIG_SILENT_CONSOLE
if (images.os.os == IH_OS_LINUX)
fixup_silent_linux();
#endif
boot_fn = boot_os[images.os.os];
if (boot_fn == NULL) {
if (iflag)
enable_interrupts();
printf ("ERROR: booting os '%s' (%d) is not supported\n",
genimg_get_os_name(images.os.os), images.os.os);
show_boot_progress (-8);
return 1;
}
arch_preboot_os();
boot_fn(0, argc, argv, &images);
show_boot_progress (-9);
#ifdef DEBUG
puts ("\n## Control returned to monitor - resetting...\n");
#endif
do_reset (cmdtp, flag, argc, argv);
return 1;
}因为要启动ｌｉｎｕｘ，所以最后调用的是do_bootm_linux。
int do_bootm_linux(int flag, int argc, char *argv[], bootm_headers_t *images)
{
bd_t *bd = gd->bd;
char *s;
int machid = bd->bi_arch_number;
void (*kernel_entry)(int zero, int arch, uint params);
#ifdef CONFIG_CMDLINE_TAG
char *commandline = getenv ("bootargs");
#endif
if ((flag != 0) && (flag != BOOTM_STATE_OS_GO))
return 1;
s = getenv ("machid");
if (s) {
machid = simple_strtoul (s, NULL, 16);
printf ("Using machid 0x%x from environment\n", machid);
}
show_boot_progress (15);
#ifdef CONFIG_OF_LIBFDT
if (images->ft_len)
return bootm_linux_fdt(machid, images);
#endif
kernel_entry = (void (*)(int, int, uint))images->ep;
debug ("## Transferring control to Linux (at address %08lx) ...\n",
(ulong) kernel_entry);
#if defined (CONFIG_SETUP_MEMORY_TAGS) || \
defined (CONFIG_CMDLINE_TAG) || \
defined (CONFIG_INITRD_TAG) || \
defined (CONFIG_SERIAL_TAG) || \
defined (CONFIG_REVISION_TAG)
setup_start_tag (bd);
#ifdef CONFIG_SERIAL_TAG
setup_serial_tag (¶ms);
#endif
#ifdef CONFIG_REVISION_TAG
setup_revision_tag (¶ms);
#endif
#ifdef CONFIG_SETUP_MEMORY_TAGS
setup_memory_tags (bd);
#endif
#ifdef CONFIG_CMDLINE_TAG
setup_commandline_tag (bd, commandline);
#endif
#ifdef CONFIG_INITRD_TAG
if (images->rd_start && images->rd_end)
setup_initrd_tag (bd, images->rd_start, images->rd_end);
#endif
setup_end_tag(bd);
#endif
announce_and_cleanup();
kernel_entry(0, machid, bd->bi_boot_params);
/* does not return */
return 1;
}当 内 核 启 动 时 , 启 动 参 数 一 般 是 从 Bootloader 中 传 递 而 来 的 。 那 么
Bootloader 传递参数的存放地址和参数的数据结构就都是需要关心的。
由于 Bootloader 和内核不是同时启动运行的,因此 Bootloader 要向内核传
递参数只有将参数存放在一个指定的地址,然后内核再从这个地址中读取启动参
数。
在 U-Boot 中,传递参数的数据结构是以标记的形式来体现的。而参数的传
递通过标记列表的形式来实现。标记列表由 ATAG_CORE 开始,以 ATAG_NONE
标记结束。这里的 ATAG_CORE,ATAG_NONE 是各个参数的标记,本身是一
个 32 位值。标记的数据结构为 tag,它由一个 tag_header 结构体和一个联合体
组成。tag_header 结构体表示标记的长度和类型,比如是表示内存还是命令行
参数。对于不同类型的标记使用不同的联合体。对于 tag 和 tag_header 的定义
可以在网蜂提供的 U-Boot 的源码中 arch/arm/include/asm/setup.h 文件中找到,
即:
struct tag
{
struct tag_header hdr;
union {
struct tag_core
core;
struct tag_mem32
mem;
struct tag_videotext
videotext;
struct tag_ramdisk
ramdisk;
struct tag_initrd
initrd;
struct tag_serialnr
serialnr;
struct tag_revision
revision;
struct tag_videolfb
videolfb;
struct tag_cmdline
cmdline;
struct tag_acorn
acorn;
struct tag_memclk
memclk;
} u;
177};
除 了 ATAG_CORE 和 ATAG_NONE 之外,其他的参数标记 还包括:
ATAG_MEM,ATAG_COMDLINE 和 ATAG_INITRD2 等。每个参数标记就代表
一个参数结构体,由各个参数结构体构成了标记列表。
在网蜂提供的 U-Boot 的源码中 arch/arm/lib/bootm.c 文件中有以下代码,说
明参数是如何传递的。
static void setup_start_tag (bd_t *bd)
{
/* 参数存放地址 */
params = (struct tag *) bd->bi_boot_params;
/* 标记 ATAG_CORE 开始 */
params->hdr.tag = ATAG_CORE;
params->hdr.size = tag_size (tag_core);
params->u.core.flags = 0;
params->u.core.pagesize = 0;
params->u.core.rootdev = 0;
/* 使 params 指向下一个标记 */
params = tag_next (params);
}
static void setup_memory_tags (bd_t *bd)
{
int i;
for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++) {
/* 设置内存标记 */
params->hdr.tag = ATAG_MEM;
params->hdr.size = tag_size (tag_mem32);
/* 设置内存起始地址 */
params->u.mem.start = bd->bi_dram[i].start;
/* 设置内存大小 */
params->u.mem.size = bd->bi_dram[i].size;
/* 使 params 指向下一个标记 */
params = tag_next (params);
}
}
static void setup_end_tag (bd_t *bd)
{
params->hdr.tag = ATAG_NONE;
params->hdr.size = 0;
}
/* 标记 ATAG_NONE 结束 */
1kernel_entry(0, machid, bd->bi_boot_params);２：倒计时中间有终端数据回来，执行ｍｅｎｕ的ｃｍｄ
run_command("menu",0);
这就是一个简单的ｃｍｄ的实现，具体实现我摘抄了网峰上的部分东西。
一、 制作 hello 命令
1. 创建 U-Boot 目录下的 common 目录中的 cmd_hello.c 文件,用命令:
vim common/cmd_hello.c
2. 在 cmd_hello.c 中添加下图内容,然后保存:
249#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
int do_hello(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
printf("\nHello world\n\n");
}
U_BOOT_CMD(hello, 4, 1, do_hello,
"test:hello",
"test:hello"
);
上面 U_BOOT_CMD 其实是一个宏,它在 include/command.h 头文件中被定义:
#define U_BOOT_CMD(name,maxargs,rep,cmd,usage,help) /
cmd_tbl_t __u_boot_cmd_##name Struct_Section =
{#name, maxargs, rep, cmd, usage, help
}
U_BOOT_CMD 中有四个参数:
name 命令的名字。
maxargs 命令执行函数中的最大参数个数。
rep 重复数。
cmd 命令执行函数名字。
usage命令用法信息。
help命令帮助信息。
也就是当我们在 U-Boot 中输入 hello,U-Boot 就会执行 do_hello 函数。
3. 打开 common 目录下的 Makefile 文件,用命令:
vim common/Makefile
4. 在 common/Makefile 文件中添加以下一行:
COBJS-y += cmd_hello.o
/* 在第 29 行添加 */
这样就能在编译 U-Boot 时,把 cmd_hello.c 编译成 cmd_hello.o,再链接到
最终生成的 bin 文件中。
5. 编译,用命令:
make webee210_config
make
把生成的 webee210-uboot.bin 烧到 SD 卡上(参考使用手册的烧写说明),然
后插到开发板,从 SD 方式启动开发板,在 U-Boot 上输入 help 命令:
可以看到,hello 命令已经存在。
好了，ｕｂｏｏｔ的整体大概流程分析已经步入尾声了，还是有很多地方不懂，但是起码懂得流程后就知道哪儿有问题，到哪里去找，然后一头扎进去，借助ｌｏｇ，应该很快就能找到原因。
不忘初心，方得始终。