S3C6410移植uboot2010.3（2）基本的启动信息修改

　　1、启动模块修改

　　进入/cpu/arm1176/目录，修改start.S文件

　　首先找到需要修改的CONFIG_NAND_SPL汇编原码，修改如下：

#ifndef CONFIG_NAND_SPL
/*
 * flush v4 I/D caches
 */
mov r0, #0
mcr p15, 0, r0, c7, c7, 0 /* flush v3/v4 cache */
mcr p15, 0, r0, c8, c7, 0 /* flush v4 TLB */
/*
 * disable MMU stuff and caches
 */
mrc p15, 0, r0, c1, c0, 0
bic r0, r0, #0x00002300 @ clear bits 13, 9:8 (--V- --RS)
bic r0, r0, #0x00000087 @ clear bits 7, 2:0 (B--- -CAM)
orr r0, r0, #0x00000002 @ set bit 2 (A) Align
orr r0, r0, #0x00001000 @ set bit 12 (I) I-Cache
//将原来之间的内容删除
mcr p15, 0, r0, c1, c0, 0
#endif

　　检索到“lowlevel_init”

　　添加如下内容，功能看注释

    /* 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, =0xff000fff
  
     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     after_copy      /* r0 == r1 then skip flash copy   */

　　此处顺便温习arm汇编

　　ldr汇编码与伪汇编码区别在于是否有“=”号

　　ldr汇编为　　ldr　　r1, [r2]， 将 r2 当作地址放入 r1 寄存器，而intel与at&t汇编的mov指令是无法对地址直接操作的。

　　ldr伪汇编为　ldr　　r1, =<constant-expression>，将<constant-expression>放入 r1 中，可以是地址，这里所用为伪汇编

　　

　　bic语法格式为 BIC{<cond>}{S} <Rd>,<Rn>,<shifter_operand>，shifter_operand取反后，和Rn与运算，值传回Rd

　　bic一般用于清零处理：

　　1、此处若系统从nandflash中启动，则pc小于4k，取反、与运算后，将0传给r1

　　此处_TEXT_BASE可能为0x57e00000或者0c7e00000，取反、与运算后，将0x00e00000传回r2

　　beq相等则跳转指令，此处 r1，r2不相等，故不跳转，继续往下执行

　　

　　2、此处若系统从ram中启动，则此处的pc应该与_TEXT_BASE相等，故直接跳转至after_copy（复制

完成）处运行。

 　　紧接着前面的代码添加下面一段代码：

#ifdef CONFIG_BOOT_NAND
    mov r0, #0x1000
    bl  copy_from_nand
#endif

　　此处的 bl 为调用子程序，接着上面的是因为未复制完成从新跳回 copy_from_nand 从新复制nandflash

　　然后找到_mmu_table_base，在它的#endif之后，添加如下代码，即上面所跳转的目标代码

/*
 * copy U-Boot to SDRAM and jump to ram (from NAND or OneNAND)
 * r0: size to be compared
 * Load 1'st 2blocks to RAM because U-boot's size is larger than 1block(128k) size
 */
    .globl copy_from_nand
copy_from_nand:
    mov r10, lr     /* save return address */

    mov r9, r0
    /* get ready to call C functions */
    ldr sp, _TEXT_PHY_BASE  /* setup temp stack pointer */
    sub sp, sp, #12
    mov fp, #0          /* no previous frame, so fp=0 */
    mov r9, #0x1000
    bl  copy_uboot_to_ram

3:  tst     r0, #0x0
    bne copy_failed

    ldr r0, =0x0c000000
    ldr r1, _TEXT_PHY_BASE
1:  ldr r3, [r0], #4
    ldr r4, [r1], #4
    teq r3, r4
    bne compare_failed  /* not matched */
    subs    r9, r9, #4
    bne 1b

4:  mov lr, r10     /* all is OK */
    mov pc, lr

copy_failed:
    nop         /* copy from nand failed */
    b   copy_failed

compare_failed:
    nop         /* compare failed */
    b   compare_failed

　　至此，start.S文件修改完成。

　　接着在/cpu/arm1176/目录下添加一个nand_cp.c文件

　　代码如下

#include <common.h>

#ifdef CONFIG_S3C64XX

#include <asm/io.h>

#include <linux/mtd/nand.h>

#include <asm/arch/s3c6410.h>



static int nandll_read_page (uchar *buf, ulong addr, int large_block)

{

    int i;

    int page_size = 512;

    /* 2K */

    if (large_block==1)

        page_size = 2048;

    /* 4K */

    if (large_block==2)

        page_size = 4096;

    NAND_ENABLE_CE();

    NFCMD_REG = NAND_CMD_READ0;

    /* Write Address */

    NFADDR_REG = 0;

    if (large_block)

        NFADDR_REG = 0;

    NFADDR_REG = (addr) & 0xff;

    NFADDR_REG = (addr >> 8) & 0xff;

    NFADDR_REG = (addr >> 16) & 0xff;

    

    if (large_block)

        NFCMD_REG = NAND_CMD_READSTART;



    NF_TRANSRnB();

    

    /* for compatibility(2460). u32 cannot be used. by scsuh */

    for(i=0; i < page_size; i++)

    {

        *buf++ = NFDATA8_REG;

    }

    

    NAND_DISABLE_CE();

    return 0;

}

static int nandll_read_blocks (ulong dst_addr, ulong size, int large_block)

{

    uchar *buf = (uchar *)dst_addr;

    int i;

    uint page_shift = 9;

    if (large_block==1)

        page_shift = 11;

    /* Read pages */

    if(large_block==2)

        page_shift = 12;

    if(large_block == 2)

    {

        /* Read pages */

        for (i = 0; i < 4; i++, buf+=(1<<(page_shift-1)))

        {

            nandll_read_page(buf, i, large_block);

        }

        /* Read pages */

        /* 0x3c000 = 11 1100 0000 0000 0000 */

        for (i = 4; i < (0x3c000>>page_shift); i++, buf+=(1<<page_shift))

        {

            nandll_read_page(buf, i, large_block);

        }

    }

    else

    {

        for (i = 0; i < (0x3c000>>page_shift); i++, buf+=(1<<page_shift))

        {

            nandll_read_page(buf, i, large_block);

        }

    }

    return 0;

}

int copy_uboot_to_ram(void)

{

    int large_block = 0;

    int i;

    vu_char id;

    /*

#define NAND_ENABLE_CE() (NFCONT_REG &= ~(1 << 1))

#define NFCONT_REG

__REG(ELFIN_NAND_BASE + NFCONT_OFFSET)

#define __REG(x) (*((volatile u32 *)(x)))

#define ELFIN_NAND_BASE 0x70200000

#define NFCONT_OFFSET 0x04

NFCONT_REG = ( *( (volatile u32 *) (0x70200004) ) )

NFCONT 0x70200004 读/写NAND Flash 控制寄存器

[0]1：NAND Flash 控制器使能

     */

    NAND_ENABLE_CE();

    /*

#define NFCMD_REG

__REG(ELFIN_NAND_BASE + NFCMMD_OFFSET)

#define ELFIN_NAND_BASE 0x70200000

#define NFCMMD_OFFSET 0x08

NFCMD_REG = ( *( (volatile u32 *) (0x70200008) ) )

NFCMMD 0x70200008 NAND Flash 命令设置寄存器0

#define NAND_CMD_READID 0x90

     */

    NFCMD_REG = NAND_CMD_READID;

    /*

#define NFADDR_REG

__REG(ELFIN_NAND_BASE + NFADDR_OFFSET)

#define ELFIN_NAND_BASE 0x70200000

#define NFADDR_OFFSET 0x0C

NFADDR_REG = ( *( (volatile u32 *) (0x7020000C) ) )

NFADDR 0x7020000C NAND Flash 地址设置寄存器

     */

    NFADDR_REG = 0x00;

    /*

#define NFDATA8_REG

__REGb(ELFIN_NAND_BASE + NFDATA_OFFSET)

#define __REGb(x) (*(vu_char *)(x))

NFDATA8_REG = ( *( (vu_char *) (0x70200010) ) )

NFDATA 0x70200010 读/写NAND Flash 数据寄存器

NAND Flash 读/烧写数据值用于I/O

     */

    /* wait for a while */

    for (i=0; i<200; i++);

    id = NFDATA8_REG;

    id = NFDATA8_REG;

    if (id > 0x80)

        large_block = 1;

    if(id == 0xd5)

        large_block = 2;

    /* read NAND Block.

     * 128KB ->240KB because of U-Boot size increase. by scsuh

     * So, read 0x3c000 bytes not 0x20000(128KB).

     */

    /*

#define CONFIG_SYS_PHY_UBOOT_BASE

(CONFIG_SYS_SDRAM_BASE + 0x07e00000)

#define CONFIG_SYS_SDRAM_BASE 0x50000000

CONFIG_SYS_PHY_UBOOT_BASE = 0x57e0 0000

0x3 c000 = 1M

     */

    return nandll_read_blocks(CONFIG_SYS_PHY_UBOOT_BASE, 0x3c000, large_block);

}

#endif

　　然后在/cpu/arm1176/makefile中添加一个依赖到COBJS目标后面

COBJS = cpu.o nand_cp.o

　　接着在/nand_spl/board/samsung/smdk6410/Makefile中添加一个依赖到COBJS后面

COBJS   = nand_boot.o nand_ecc.o s3c64xx.o nand_cp.o

　　补全规则

# from SoC directory
$(obj)cpu_init.S:
    @rm -f $@
    @ln -s $(TOPDIR)/cpu/arm1176/s3c64xx/cpu_init.S $@
$(obj)nand_cp.c:
    @rm -f $@
    @ln -s $(TOPDIR)/cpu/arm1176/nand_cp.c $@

　　接着修改smdk6410.h文件（在/include/configs/目录下）：

　　1、添加宏定义

#define virt_to_phys(x) virt_to_phy_smdk6410(x)

　　2、用户名回显修改

#define CONFIG_SYS_PROMPT  "SMDK6400 #" 

　3、添加smdk6410 ID
　检索到MACH_TYPE，将其注释掉，然后添加smdk6410 ID如下

#define MACH_TYPE       1626

　4、增加NAND config的内容

　　添加位置 /* NAND configuration */

#define NAND_DISABLE_CE()(NFCONT_REG |=(1<<1))
#define NAND_ENABLE_CE()(NFCONT_REG &=~(1<<1))
#define NF_TRANSRnB() do{while(!(NFSTAT_REG&(1<<0)));}while(0)

　　5、NAND flash 大小

//#define PHYS_SDRAM_1_SIZE 0x08000000  /* 128 MB in Bank #1    */
#define PHYS_SDRAM_1_SIZE   0x10000000  /* 256 MB in Bank #1    */

　　6、NAND flash块大小

/* NAND chip block size     */
//#define CONFIG_SYS_NAND_BLOCK_SIZE    (128 * 1024)
#define CONFIG_SYS_NAND_BLOCK_SIZE  (512 * 1024)

　　7、NAND flash页大小

/* NAND chip page size      */
//#define CONFIG_SYS_NAND_PAGE_SIZE 2048
#define CONFIG_SYS_NAND_PAGE_SIZE   4096

　8、位校验

/* NAND chip page per block count  */
//#define CONFIG_SYS_NAND_PAGE_COUNT    64
#define CONFIG_SYS_NAND_PAGE_COUNT  128

　9、更改内存分配空间

/*
 * Size of malloc() pool
 */
//#define CONFIG_SYS_MALLOC_LEN         (CONFIG_ENV_SIZE + 1024 * 1024)
#define CONFIG_SYS_MALLOC_LEN           (CONFIG_ENV_SIZE + 512 * 1024)

　　10、修改开机延迟时间

#define CONFIG_BOOTDELAY    3

　　11、设置SDRAM大小

//#define PHYS_SDRAM_1_SIZE 0x08000000 /* 128 MB in Bank #1 */
#define PHYS_SDRAM_1_SIZE 0x10000000 /* 256 MB in Bank #1 */
/* 后面的大小自己设定 这里是256MB的SDRAM */

　12、修改SDROM大小

//#define CONFIG_SYS_MEMTEST_END        (CONFIG_SYS_SDRAM_BASE + 0x7e00000) /* 126MB in DRAM */
#define CONFIG_SYS_MEMTEST_END      (CONFIG_SYS_SDRAM_BASE + 0x9e00000) /* 256MB in DRAM */

　　13、PWM设置

//#define CONFIG_SYS_HZ         1000
#define CONFIG_SYS_HZ           1562500

　　14、堆栈大小

/*-----------------------------------------------------------------------
 * Stack sizes
 *
 * The stack sizes are set up in start.S using the settings below
 */
//#define CONFIG_STACKSIZE  0x40000     /* regular stack 256KB */
#define CONFIG_STACKSIZE    0x80000     /* regular stack 512KB */

　　15、环境变量空间

//#define CONFIG_ENV_SIZE       0x4000  /* Total Size of Environment Sector */
#define CONFIG_ENV_SIZE     0x80000 /* Total Size of Environment Sector */

　　16、环境变量偏移地址

//#define CONFIG_ENV_OFFSET     0x0040000
#define CONFIG_ENV_OFFSET       0x0080000

　　17、BOOTCOMMAND

　　更改后的内容为

#ifdef CONFIG_ENABLE_MMU
#define CONFIG_SYS_MAPPED_RAM_BASE      0xc0000000
#define CONFIG_BOOTCOMMAND      "nand read 0xc0008000 0x100000 0x500000;" \
                                "bootm 0xc0008000"
#else
#define CONFIG_SYS_MAPPED_RAM_BASE      CONFIG_SYS_SDRAM_BASE
#define CONFIG_BOOTCOMMAND      "nand read 0x50008000 0x100000 0x500000;" \
                                "bootm 0x50008000"
#endif

　　

　　然后开始添加内容到u-boot.lds，在目录cpu/arm1176/还有uboot根目录下面都有

　　完善如下代码段

    . = ALIGN(4);
    .text :
    {   
        cpu/arm1176/start.o (.text)
        cpu/arm1176/s3c64xx/cpu_init.o (.text)
        board/samsung/smdk6410/lowlevel_init.o (.text)
        cpu/arm1176/nand_cp.o (.text)
        lib_arm/board.o (.text)
        *(.text)
    }   

　　添加内容到u-boot-nand.lds，在目录/board/samsung/smdk6410中

　　完善如下代码

        . = ALIGN(4);
        .text      :
        {
                cpu/arm1176/start.o     (.text)
                cpu/arm1176/s3c64xx/cpu_init.o  (.text)
                board/samsung/smdk6410/lowlevel_init.o  (.text)
                cpu/arm1176/nand_cp.o   (.text)
                lib_arm/board.o (.text)
                *(.text)
        }

　　接着就可以回到根目录进行make了。

　　然后就可以看到你的uboot正式运转了…、