手把手教你移植u-boot(目标平台S3C2410)

U-Boot(Universal Boot Loader)是德国DENX小组开发的用于多种嵌入式CPU的BootLoader程序,它可以运行于PowerPC、ARM、MIPS等多种嵌入式开发板上。

u-boot目录的源码结构如下:

board:开发板相关目录。

common:通用的命令函数。

cpu:特定CPU架构相关目录,如arm920t。

doc:uboot的开发、使用文档。

drivers:uboot支持的设备驱动程序,比如串口,nandflash,网卡。

fs: 支持的文件系统,Uboot现在支持cramfs、fat、fdos、jffs2和registerfs。

include:头文件和开发板配置文件,configs目录下是开发板的配置文件

lib_xxxx: 与体系结构相关的库文件。如与ARM相关的库放在lib_arm中。

lib_generic:通用的库函数。

net:各种网络协议,TFTP协议、NFS协议等。

tools:uboot自带的工具。

下面我们就针对S3C2410平台u-boot的移植步骤做一下简单介绍:

1、首先下载u-boot的源码包,然后解压,进入源码包目录。

2、修改源码让u-boot支持从Nand Flash启动。

具体如下:

一、修改“u-boot-1.3.2/cpu/arm920t/start.S”文件,执行以下命令:

#gedit cpu/arm920t/start.S

(1)181行和201行前加上//,注释掉

181 //#ifdef CONFIG_AT91RM9200

201 //#endif

(2)#ifndef CONFIG_SKIP_RELOCATE_UBOOT之后加入:

#ifdef CONFIG_S3C2410_NAND_BOOT

bl copy_myself

#else

(3)“ble copy_loop”语句之后加入:

#endif

(4)“_start_armboot: .word start_armboot”语句之后加入copy_loop子程序:

/*

*************************************************************************

*

* copy u-boot to ram

*

*************************************************************************

*/

#ifdef CONFIG_S3C2410_NAND_BOOT

copy_myself:

mov r10, lr @save return address to r10

ldr sp, DW_STACK_START

mov fp, #0

bl NF_Init

ldr r0, =UBOOT_RAM_BASE

mov r1, #0x0

mov r2, #0x30000

bl nand_read_whole

tst r0, #0x0

beq ok_nand_read

1: b 1b

ok_nand_read:

mov r0, #0x00000000

ldr r1, =UBOOT_RAM_BASE

mov r2, #0x400

go_next:

ldr r3, [r0], #4

ldr r4, [r1], #4

teq r3, r4

bne notmatch

subs r2, r2, #4

beq done_nand_read

bne go_next

notmatch:

1: b 1b

done_nand_read:

mov pc, r10

#endif

DW_STACK_START:

.word STACK_BASE+STACK_SIZE-4

二、新建“u-boot-1.3.2/ board/smdk2410/nand.c”文件

执行命令:

#gedit board/up2410/nand.c

在打开的文件里添加如下内容:

#include

#include

#include

#define TACLS 0

#define TWRPH0 3

#define TWRPH1 0

#define U32 unsigned int

extern unsigned long nand_probe(unsigned long physadr);

static void NF_Reset(void)

{

int i;

NF_nFCE_L();

NF_CMD(0xFF);

for(i=0;i<10;i++);

NF_WAITRB();

NF_nFCE_H();

}

void NF_Init(void)

{

rNFCONF=(1<<15)|(1<<14)|(1<<13)|(1<<12)|(1<<11)|(TACLS<<8)|(TWRPH0<<4)|(TWRPH1<<0);

NF_Reset();

}

int nand_read_whole(unsigned char *buf, unsigned long start_addr, int size)

{

int i, j;

if((start_addr & NAND_BLOCK_MASK) || (size & NAND_BLOCK_MASK))

return 1;

NF_nFCE_L();

for(i=0; i<10; i++);

i = start_addr;

while(i < start_addr + size) {

rNFCMD = 0;

rNFADDR = i & 0xff;

rNFADDR = (i >> 9) & 0xff;

rNFADDR = (i >> 17) & 0xff;

rNFADDR = (i >> 25) & 0xff;

NF_WAITRB();

for(j=0; j < NAND_SECTOR_SIZE; j++, i++) {

*buf = (rNFDATA & 0xff);

buf++;

}

}

NF_nFCE_H();

return 0;

}

三、修改“u-boot-1.3.2/board/smdk2410/Makefile”文件

执行命令:

#gedit board/smdk2410/Makefile

将“COBJS:= smdk2410.o flash.o”改为“COBJS:=smdk2410.o flash.o nand.o”

四、修改“u-boot-1.3.2/include/configs/smdk2410.h”文件

执行命令:

#gedit include/configs/smdk2410.h

在文件的最后一个#endif的前面添加如下内容:

#define CONFIG_S3C2410_NAND_BOOT 1

#define STACK_BASE 0x33f00000

#define STACK_SIZE 0x8000

#define UBOOT_RAM_BASE 0x33f80000

#define CFG_NAND_BASE 0x4E000000

#define CFG_MAX_NAND_DEVICE 1

#define SECTORSIZE 512

#define NAND_SECTOR_SIZE SECTORSIZE

#define NAND_BLOCK_MASK (NAND_SECTOR_SIZE - 1)

#define ADDR_COLUMN 1

#define ADDR_PAGE 2

#define ADDR_COLUMN_PAGE 3

#define NAND_ChipID_UNKNOWN 0x00

#define NAND_MAX_FLOORS 1

#define NAND_MAX_CHIPS 1

#define WRITE_NAND_COMMAND(d, adr) do {rNFCMD = d;} while(0)

#define WRITE_NAND_ADDRESS(d, adr) do {rNFADDR = d;} while(0)

#define WRITE_NAND(d, adr) do {rNFDATA = d;} while(0)

#define READ_NAND(adr) (rNFDATA)

#define NAND_WAIT_READY(nand) {while(!(rNFSTAT&(1<<0)));}

#define NAND_DISABLE_CE(nand) {rNFCONF |= (1<<11);}

#define NAND_ENABLE_CE(nand) {rNFCONF &= ~(1<<11);}

#define NAND_CTL_CLRALE(nandptr)

#define NAND_CTL_SETALE(nandptr)

#define NAND_CTL_CLRCLE(nandptr)

#define NAND_CTL_SETCLE(nandptr)

#define CONFIG_MTD_NAND_VERIFY_WRITE 1

#define rNFCONF (*(volatile unsigned int *)0x4e000000)

#define rNFCMD (*(volatile unsigned char *)0x4e000004)

#define rNFADDR (*(volatile unsigned char *)0x4e000008)

#define rNFDATA (*(volatile unsigned char *)0x4e00000c)

#define rNFSTAT (*(volatile unsigned int *)0x4e000010)

#define rNFECC (*(volatile unsigned int *)0x4e000014)

#define rNFECC0 (*(volatile unsigned char *)0x4e000014)

#define rNFECC1 (*(volatile unsigned char *)0x4e000015)

#define rNFECC2 (*(volatile unsigned char *)0x4e000016)

#define NF_CMD(cmd) {rNFCMD=cmd;}

#define NF_ADDR(addr) {rNFADDR=addr;}

#define NF_nFCE_L() {rNFCONF&=~(1<<11);}

#define NF_nFCE_H() {rNFCONF|=(1<<11);}

#define NF_RSTECC() {rNFCONF|=(1<<12);}

#define NF_RDDATA() (rNFDATA)

#define NF_WRDATA(data) {rNFDATA=data;}

#define NF_WAITRB() {while(!(rNFSTAT&(1<<0)));}

3、使u-boot支持dm9000网卡

步骤如下:

一、将dm9000x.h和dm9000x.c两个文件拷贝到drivers/net/下。

二、2. 修改“u-boot-1.3.2/include/configs/smdk2410.h”文件

执行命令:

#gedit include/configs/smdk2410.h

(1)将原网卡“CS8900”改为“DM9000”

(2)添加网络命令

(3)修改IP地址

(4)修改命令提示符

(5)修改默认下载地址

(6)修改环境变量在Nand Flash中的存储地址

具体如下:

(1)将原网卡“CS8900”改为“DM9000”

注释掉:

// #define CONFIG_DRIVER_CS8900 1 /* we have a CS8900 on-board */

// #define CS8900_BASE 0x19000300

// #define CS8900_BUS16 1 /* the Linux driver does accesses as shorts */

这3行之后添加:

#define CONFIG_DRIVER_DM9000 1

#define CONFIG_DRIVER_DM9000_BASE 0x10000000

#define DM9000_IO CONFIG_DM9000_BASE

#define DM9000_DATA (DM9000_IO + 2)

#define CONFIG_DM9000_USE_16BIT

(2)添加网络命令

找到下面的几行:

#define CONFIG_CMD_CACHE

#define CONFIG_CMD_DATE

#define CONFIG_CMD_ELF

在其下面添加下面几行:

#define CONFIG_CMD_REGINFO

#define CONFIG_CMD_NAND

#define CONFIG_CMD_PING

#define CONFIG_CMD_DLF

#define CONFIG_CMD_ENV

#define CONFIG_CMD_NET

(3)修改IP地址

找到下面几行:

#define CONFIG_BOOTDELAY 3

/*#define CONFIG_BOOTARGS "root=ramfs devfs=mount console=ttySA0,9600" */

/*#define CONFIG_ETHADDR 08:00:3e:26:0a:5b */

#define CONFIG_NETMASK 255.255.255.0

#define CONFIG_IPADDR 10.0.0.110

#define CONFIG_SERVERIP 10.0.0.1

/*#define CONFIG_BOOTFILE "elinos-lart" */

/*#define CONFIG_BOOTCOMMAND "tftp; bootm" */

修改为:

#define CONFIG_BOOTDELAY 3

#define CONFIG_BOOTARGS "root=/dev/mtdblock3 init=/linuxrc console=ttySAC0,115200"

#define CONFIG_ETHADDR 08:00:3e:26:0a:5b

#define CONFIG_NETMASK 255.255.255.0

#define CONFIG_IPADDR 192.168.1.13

#define CONFIG_SERVERIP 192.168.1.12

#define CONFIG_BOOTFILE "uImage"

#define CONFIG_BOOTCOMMAND "tftp; bootm"

#define CONFIG_CMDLINE_TAG 1

#define CONFIG_SETUP_MEMORY_TAGS 1

#define CONFIG_INITRD_TAG 1

(4)修改命令提示符

找到下面一行:

#define CFG_PROMPT "SMDK2410 # "

修改为:

#define CFG_PROMPT "[ smdk2410 #]"

(5)修改默认下载地址

找到下面一行:

#define CFG_LOAD_ADDR 0x33000000

修改为:

#define CFG_LOAD_ADDR 0x30008000

#define CFG_TFTP_LOAD_ADDR 0x30008000

(6)修改环境变量在Nand Flash中的存储地址

找到下面两行:

#define CFG_ENV_IS_IN_FLASH 1

#define CFG_ENV_SIZE 0x10000

修改为:

#define CFG_ENV_IS_IN_NAND 1

#define CFG_ENV_SIZE 0x4000

#define CFG_ENV_OFFSET (0x80000-0x4000)

4、编译生成u-boot

依次执行以下命令:

#make smdk2410_config

#make

编译完成之后就生成了u-boot.bin文件,这个文件就是我们要烧写到开发板上的文件。

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