裸机——210SD卡启动

1.通过阅读iROM_Application_note可以获取关于启动的全部信息

　　

2.记录下代码

制作SD卡启动的代码，即添加校验和的

#include <strings.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#define BL1SIZE        (16*1024)
#define HEADSIZE    (16)    

static void sys_err(char *str)
{
    perror(str);
    exit();
}

int main(int argc, char **argv)
{
    ) {
        printf("format: a.out [infile] [outfile]\n");
        ;
    }

    int fd;
    ], O_RDONLY)) < )
        sys_err("open");

    ;
    , SEEK_END)) < )
        sys_err("lseek");
    , SEEK_SET)) < )
        sys_err("lseek 2");

    ;
    char *newfile = NULL;
    if (filesize < BL1SIZE) {
        newfilesize = BL1SIZE + HEADSIZE;
    } else {
        newfilesize = filesize + HEADSIZE;
    }
    if ((newfile = (char *)malloc(newfilesize)) == NULL)
        sys_err("malloc newfile");
    bzero(newfile, newfilesize);

    int ncount;
    )
        sys_err("read err");
    if (ncount != filesize) {
        printf("read err 2\n");
        exit();
    }

    ;
    char *getsum = newfile + HEADSIZE;
    unsigned , count = ;
    for (; count < BL1SIZE - HEADSIZE; count++) {
        sum += getsum[count] & 0xff;
    }
    *(unsigned int *)checksum = sum;

    int newfd;
    ], O_WRONLY | O_CREAT | O_TRUNC, )) < )
        sys_err("open outfile");

    )
        sys_err("write outfile");
    if (ncount != newfilesize) {
        printf("write outfile err\n");
        exit();
    }

    ;
}

使用 dd 命令，将SD卡启动代码拷贝到 SD 的 block1

#/bin/sh
sudo dd iflag=dsync oflag=dsync 

使用iROM中的库将SD卡中的代码考到DDR上

typedef unsigned int bool;

typedef bool (*pfunc_t) (int , unsigned int , unsigned short, unsigned int* , bool );
/**
* This Function copy MMC(MoviNAND/iNand) Card Data to memory.
* Always use EPLL source clock.
* This function works at 20Mhz.
* @param u32 StartBlkAddress : Source card(MoviNAND/iNand MMC)) Address.(It must block address.)
* @param u16 blockSize : Number of blocks to copy.
* @param u32* memoryPtr : Buffer to copy from.
* @param bool with_init : determined card initialization.
* @return bool(u8) - Success or failure.
*/

#define channel            2
#define StartBlkAddress    1
#define blockSize        50
#define memoryPtr        0x20000000
#define with_init        0

void sd_relcate()
{
    pfunc_t pfunc = (pfunc_t)(*(unsigned int *)0xD0037F98);

    if (!pfunc(channel, StartBlkAddress, blockSize, memoryPtr, with_init))
        printf("sd_relcate err\n");
    else
        printf("sd_relcate success\n");
}

在汇编中，使用长跳转，跳转到DDR上的main

    bl sdram_asm_init

    bl sd_relcate

    ldr sp, =0x2E000000　　// 在DDR上重新设置栈

    ldr pc, =main