uboot分析第二阶段学习笔记

=====================================================================
第二阶段工作
1 从FLASH读出内核
2 启动内核
======================================================================
第一种方法是从nand启动 先执行nand_spl\Nand_boot.c
后从arc/arm/lib下的boot.c作一些初始化的工作
以下的arc/arm/lib下的boot.c
/*
* (C) Copyright 2002-2006
* Wolfgang Denk, DENX Software Engineering, [e-mail].
*
* (C) Copyright 2002
* Sysgo Real-Time Solutions, GmbH <www.elinos.com>
* Marius Groeger <[e-mail]>
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/

/*
* To match the U-Boot user interface on ARM platforms to the U-Boot
* standard (as on PPC platforms), some messages with debug character
* are removed from the default U-Boot build.
*
* Define DEBUG here if you want additional info as shown below
* printed upon startup:
*
* U-Boot code: 00F00000 -> 00F3C774 BSS: -> 00FC3274
* IRQ Stack: 00ebff7c
* FIQ Stack: 00ebef7c
*/

#include <common.h>
#include <command.h>
#include <malloc.h>
#include <stdio_dev.h>
#include <timestamp.h>
#include <version.h>
#include <net.h>
#include <serial.h>
#include <nand.h>
#include <onenand_uboot.h>
#include <mmc.h>

#ifdef CONFIG_BITBANGMII
#include <miiphy.h>
#endif

#ifdef CONFIG_DRIVER_SMC91111
#include "../drivers/net/smc91111.h"
#endif
#ifdef CONFIG_DRIVER_LAN91C96
#include "../drivers/net/lan91c96.h"
#endif
#if defined(CONFIG_MINI6410_LED)
#include <asm/arch/s3c6400.h>
#endif

DECLARE_GLOBAL_DATA_PTR;

ulong monitor_flash_len;

#ifdef CONFIG_HAS_DATAFLASH
extern int AT91F_DataflashInit(void);
extern void dataflash_print_info(void);
#endif

#ifndef CONFIG_IDENT_STRING
#define CONFIG_IDENT_STRING ""
#endif

const char version_string[] =
U_BOOT_VERSION" (" U_BOOT_DATE " - " U_BOOT_TIME ")"CONFIG_IDENT_STRING;

#ifdef CONFIG_DRIVER_RTL8019
extern void rtl8019_get_enetaddr (uchar * addr);
#endif

#if defined(CONFIG_HARD_I2C) || \
defined(CONFIG_SOFT_I2C)
#include <i2c.h>
#endif

/************************************************************************
* Coloured LED functionality
************************************************************************
* May be supplied by boards if desired
*/
void inline __coloured_LED_init (void) {}
void coloured_LED_init (void) __attribute__((weak, alias("__coloured_LED_init")));
void inline __red_LED_on (void) {}
void red_LED_on (void) __attribute__((weak, alias("__red_LED_on")));
void inline __red_LED_off(void) {}
void red_LED_off(void) __attribute__((weak, alias("__red_LED_off")));
void inline __green_LED_on(void) {}
void green_LED_on(void) __attribute__((weak, alias("__green_LED_on")));
void inline __green_LED_off(void) {}
void green_LED_off(void) __attribute__((weak, alias("__green_LED_off")));
void inline __yellow_LED_on(void) {}
void yellow_LED_on(void) __attribute__((weak, alias("__yellow_LED_on")));
void inline __yellow_LED_off(void) {}
void yellow_LED_off(void) __attribute__((weak, alias("__yellow_LED_off")));
void inline __blue_LED_on(void) {}
void blue_LED_on(void) __attribute__((weak, alias("__blue_LED_on")));
void inline __blue_LED_off(void) {}
void blue_LED_off(void) __attribute__((weak, alias("__blue_LED_off")));

/************************************************************************
* Init Utilities*
************************************************************************
* Some of this code should be moved into the core functions,
* or dropped completely,
* but let's get it working (again) first...
*/

#if defined(CONFIG_ARM_DCC) && !defined(CONFIG_BAUDRATE)
#define CONFIG_BAUDRATE 115200
#endif
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);
}

static int display_banner (void)
{
printf ("\n\n%s\n\n", version_string);
debug ("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);
}

/*
* 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)
{
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);
}

#if defined(CONFIG_HARD_I2C) || defined(CONFIG_SOFT_I2C)
static int init_func_i2c (void)
{
puts ("I2C: ");
i2c_init (CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
puts ("ready\n");
return (0);
}
#endif

#if defined(CONFIG_CMD_PCI) || defined (CONFIG_PCI)
#include <pci.h>
static int arm_pci_init(void)
{
pci_init();
return 0;
}
#endif /* CONFIG_CMD_PCI || CONFIG_PCI */

/*
* 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.
*/

/*
* 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".
*/
typedef int (init_fnc_t) (void);

int print_cpuinfo (void);

void __dram_init_banksize(void)
{
gd->bd->bi_dram[0].start = CONFIG_SYS_SDRAM_BASE;
gd->bd->bi_dram[0].size = gd->ram_size;
}
void dram_init_banksize(void)
__attribute__((weak, alias("__dram_init_banksize")));

init_fnc_t *init_sequence[] = {
#if defined(CONFIG_ARCH_CPU_INIT)
arch_cpu_init,/* basic arch cpu dependent setup */
#endif
#if defined(CONFIG_BOARD_EARLY_INIT_F)
board_early_init_f,
#endif
timer_init,/* initialize timer */
#ifdef CONFIG_FSL_ESDHC
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)
init_func_i2c,
#endif
dram_init,/* configure available RAM banks */
#if defined(CONFIG_CMD_PCI) || defined (CONFIG_PCI)
arm_pci_init,
#endif
NULL,
};

void board_init_f (ulong bootflag)
{
bd_t *bd;
init_fnc_t **init_fnc_ptr;
gd_t *id;
ulong addr, addr_sp;
#if defined(CONFIG_MINI6410_LED)
s3c64xx_gpio * const gpio = s3c64xx_get_base_gpio();
#endif
/* Pointer is writable since we allocated a register for it */
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));

gd->mon_len = _bss_end_ofs;

for (init_fnc_ptr = init_sequence; *init_fnc_ptr; ++init_fnc_ptr) {
if ((*init_fnc_ptr)() != 0) {
hang ();
}
}

debug ("monitor len: %08lX\n", gd->mon_len);
/*
* Ram is setup, size stored in gd !!
*/
debug ("ramsize: %08lX\n", gd->ram_size);
#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

#ifdef CONFIG_PRAM
/*
* 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_NO_ICACHE) && defined(CONFIG_SYS_NO_DCACHE))
/* reserve TLB table */
addr -= (4096 * 4);

/* round down to next 64 kB limit */
addr &= ~(0x10000 - 1);

gd->tlb_addr = addr;
debug ("TLB table at: %08lx\n", addr);
#endif

/* round down to next 4 kB limit */
addr &= ~(4096 - 1);
debug ("Top of RAM usable for U-Boot at: %08lx\n", addr);

#ifdef CONFIG_VFD
#ifndef PAGE_SIZE
# define PAGE_SIZE 4096
#endif
/*
* reserve memory for VFD display (always full pages)
*/
addr -= vfd_setmem (addr);
gd->fb_base = addr;
#endif /* CONFIG_VFD */

#ifdef CONFIG_LCD
/* reserve memory for LCD display (always full pages) */
addr = lcd_setmem (addr);
gd->fb_base = 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);

#if defined(CONFIG_SKIP_RELOCATE_UBOOT)
addr = CONFIG_SYS_PHY_UBOOT_BASE;//FIXME
#endif

debug ("Reserving %ldk for U-Boot at: %08lx\n", gd->mon_len >> 10, addr);
#ifndef CONFIG_PRELOADER
/*
* 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);
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 -= 3;

/* 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

debug ("New Stack Pointer is: %08lx\n", addr_sp);
#ifdef CONFIG_POST
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;
debug ("relocation Offset is: %08lx\n", gd->reloc_off);
memcpy (id, (void *)gd, sizeof (gd_t));
#if defined(CONFIG_MINI6410_LED)
debug ("relocate_code : text --> 0X%p gd --> 0X%p sp --> 0X%p \n",
(void *)addr, (void *)id, (void *)addr_sp);
gpio->GPKDAT &= ~0x20;
#endif
relocate_code (addr_sp, id, addr);
}

#if !defined(CONFIG_SYS_NO_FLASH)
static char *failed = "*** failed ***\n";
#endif

/************************************************************************
*
* 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
#if defined(CONFIG_MINI6410_LED)
s3c64xx_gpio * const gpio = s3c64xx_get_base_gpio();
#endif
gd = id;
bd = gd->bd;

gd->flags |= GD_FLG_RELOC;/* tell others: relocation done */

monitor_flash_len = _bss_start_ofs;
debug ("monitor flash len: %08lX\n", monitor_flash_len);
board_init();/* Setup chipselects */

#ifdef CONFIG_SERIAL_MULTI
serial_initialize();
#endif

debug ("Now running in RAM - U-Boot at: %08lx\n", dest_addr);

#ifdef CONFIG_LOGBUFFER
logbuff_init_ptrs ();
#endif
#ifdef CONFIG_POST
post_output_backlog ();
#endif
/*对flash的初始化*/
/* 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);

#if !defined(CONFIG_SYS_NO_FLASH)
puts ("FLASH: ");

if ((flash_size = flash_init ()) > 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
/*nand的初始化*/
#if defined(CONFIG_CMD_NAND)
puts ("NAND: ");
nand_init();/* go init the NAND */
#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();
#endif
/*设置环境变量 默认的和在flash上保存的*/
/* initialize environment */
env_relocate ();

#ifdef CONFIG_VFD
/* must do this after the framebuffer is allocated */
drv_vfd_init();
#endif /* CONFIG_VFD */

/* IP Address */
gd->bd->bi_ip_addr = getenv_IPaddr ("ipaddr");

stdio_init ();/* get the devices list going. */

jumptable_init ();

#if defined(CONFIG_API)
/* Initialize API */
api_init ();
#endif

console_init_r ();/* fully init console as a device */

#if defined(CONFIG_ARCH_MISC_INIT)
/* miscellaneous arch dependent initialisations */
arch_misc_init ();
#endif
#if defined(CONFIG_MISC_INIT_R)
/* miscellaneous platform dependent initialisations */
misc_init_r ();
#endif

/* set up exceptions */
interrupt_init ();
/* enable exceptions */
enable_interrupts ();

/* Perform network card initialisation if necessary */
#if defined(CONFIG_DRIVER_SMC91111) || defined (CONFIG_DRIVER_LAN91C96)
/* 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 */
if ((s = getenv ("loadaddr")) != NULL) {
load_addr = simple_strtoul (s, NULL, 16);
}
#if defined(CONFIG_CMD_NET)
if ((s = getenv ("bootfile")) != NULL) {
copy_filename (BootFile, s, sizeof (BootFile));
}
#endif

#ifdef BOARD_LATE_INIT
board_late_init ();
#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);
#if defined(CONFIG_RESET_PHY_R)
debug ("Reset Ethernet PHY\n");
reset_phy();
#endif
#endif

#ifdef CONFIG_POST
post_run (NULL, POST_RAM | post_bootmode_get(0));
#endif

#if defined(CONFIG_PRAM) || defined(CONFIG_LOGBUFFER)
/*
* 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
char *s;

if ((s = getenv ("pram")) != 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", (bd->bi_memsize / 1024) - pram);
setenv ("mem", (char *)memsz);
}
#endif
#if defined(CONFIG_MINI6410_LED)
debug ("init finish! goto command loop!\n");
gpio->GPKDAT &= ~0x10;
#endif
{
uchar ramsize[10];
sprintf(ramsize, "%dM", (gd->ram_size/1024/1024));
if (setenv("ramsize", ramsize) != 0){
printf("set ramsize error!!\n");
}
}
/**/
/* main_loop() can return to retry autoboot, if so just run it again. */
for (;;) {
/*跳转到common下的main.c*/
/*s = getenv ("bootdelay");取环境变量*/
/*s = getenv ("bootcmd");启动内核命令*/
/*run_command (s, 0);如果倒数计时时没有按空格，就执行此命令*/
/* This point is never reached 等待串口输入 */
/* for (;;);*/
/*cmd_tbl_s 命令的结构体*/
main_loop ();
}

/* NOTREACHED - no way out of command loop except booting */
}

void hang (void)
{
puts ("### ERROR ### Please RESET the board ###\n");
for (;;);
}