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 (;;);
}