u-boot-2014.10移植（8）重定位，支持NAND启动

前面链接地址都是0x0，可以从nor正常启动内核和文件系统。

现在把链接地址改成0x33f00000

一旦更改了链接地址， u-boot从nor flash加载时，串口没有任何输出

添加文件boot_init.c

#define NFCONF (*((volatile unsigned long *)0x4E000000))

#define NFCONT (*((volatile unsigned long *)0x4E000004))

#define NFCMMD (*((volatile unsigned char *)0x4E000008))

#define NFADDR (*((volatile unsigned char *)0x4E00000C))

#define NFDATA (*((volatile unsigned char *)0x4E000010))

#define NFSTAT (*((volatile unsigned char *)0x4E000020))

static void nand_select(void)

{

    NFCONT &= ~(1<<1);    

}

static void nand_deselect(void)

{

    NFCONT |= (1<<1);    

}

static void nand_cmd(unsigned char cmd)

{

    volatile int i;

    NFCMMD = cmd;

    for (i = 0; i < 10; i++);

}

static void nand_addr(unsigned int addr)

{

    unsigned int col  = addr % 2048;

    unsigned int page = addr / 2048;

    volatile int i;

    NFADDR = col & 0xff;

    for (i = 0; i < 10; i++);

    NFADDR = (col >> 8) & 0xff;

    for (i = 0; i < 10; i++);

    NFADDR  = page & 0xff;

    for (i = 0; i < 10; i++);

    NFADDR  = (page >> 8) & 0xff;

    for (i = 0; i < 10; i++);

    NFADDR  = (page >> 16) & 0xff;

    for (i = 0; i < 10; i++);    

}

static void nand_wait_ready(void)

{

    while (!(NFSTAT & 1));

}

static unsigned char nand_data(void)

{

    return NFDATA;

}

static void nand_read_ll(unsigned int addr, unsigned char *buf, unsigned int len)

{

    int col = addr % 2048;

    int i = 0;

    nand_select();

    while (i < len)

    {

        nand_cmd(0x00);

        nand_addr(addr);

        nand_cmd(0x30);

        nand_wait_ready();

        for (; (col < 2048) && (i < len); col++)

        {

            buf[i] = nand_data();

            i++;

            addr++;

        }

        col = 0;

    }

    nand_deselect();

}

static void nand_init(void)

{

#define TACLS   0

#define TWRPH0  1

#define TWRPH1  0

    NFCONF = (TACLS<<12)|(TWRPH0<<8)|(TWRPH1<<4);

    NFCONT = (1<<4)|(1<<1)|(1<<0);    

}

/* 1: from nor 0: from nand */

static int isBootFromNorFlash(void)

{

    volatile int *p = (volatile int *)0;

    int val;

    val = *p;

    *p = 0x12345678;

    if (*p == 0x12345678)

    {

        *p = val;

        return 0;

    }

    else

    {

        // nor

        return 1;

    }

}

void copy_code_to_sdram(unsigned char *src, unsigned char *dest, unsigned int len)

{

    int i = 0;

    if (isBootFromNorFlash())

    {

        while (i < len)

        {

            dest[i] = src[i];

            i++;

        }

    }

      else     // from nand

      {

        nand_init();

        nand_read_ll((unsigned int)src, dest, len);

    }

}

void clear_bss(void)

{

    extern int __bss_start, __bss_end;

    int *p = &__bss_start;

    for (; p < &__bss_end; p++)

        *p = 0;

}    

修改对应目录Makefile

obj-y   := smdk2440.o boot_init.o

把smdk2440/目录下内容放最前面，满足4K内

vim arch/arm/cpu/u-boot.lds

board/samsung/smdk2440/built-in.o (.text*)

修改重定位代码：

#if defined(CONFIG_SYS_MALLOC_F_LEN) && !defined(CONFIG_SPL_BUILD)

        sub     sp, sp, #CONFIG_SYS_MALLOC_F_LEN

        str     sp, [r9, #GD_MALLOC_BASE]

        #endif

    #if defined(CONFIG_S3C2440)

        mov r0, #0

        ldr r1, = CONFIG_SYS_TEXT_BASE

        ldr r2, = CONFIG_SYS_TEXT_BASE

        ldr r3, =__bss_end

        sub r2, r3, r2

        bl copy_code_to_sdram

        bl clear_bss

        ldr pc, =call_board_init_f

call_board_init_f:

        mov     r0, #0

        bl      board_init_f

        ldr     sp, [r9, #GD_START_ADDR_SP]     /* sp = gd->start_addr_sp */

        bic     sp, sp, #7                      /* 8-byte alignment for ABI compliance */

        ldr     r9, [r9, #GD_BD]                /* r9 = gd->bd */

        sub     r9, r9, #GD_SIZE                /* new GD is below bd */

        mov r0, r9

        ldr r1, = CONFIG_SYS_TEXT_BASE

        bl  board_init_r

#else

        /* mov r0, #0 not needed due to above code */

        bl      board_init_f

        ...

#endif

去掉pie选项vim arch/arm/config.mk

#LDFLAGS_u-boot += -pie

#ALL-y += checkarmreloc

此外board.c里面还应修改

board_init_f

    //addr -= gd->mon_len;

        //addr &= ~(4096 - 1);

        addr = CONFIG_SYS_TEXT_BASE ; 

烧写u-boot到nand

bootloader:

    tftp 30000000 u-boot.bin

    nand erase.part bootloader

    nand write.jffs2 30000000 bootloader

烧写u-boot到nor

tftp 30000000 u-boot.bin

    protect off all

    erase 0 3ffff   (256K)

    cp.b 30000000 0 40000