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U-boot在S3C2440上的移植详解(二)


一、移植环境

  • 主  机:VMWare--Fedora 9
  • 开发板:Mini2440--64MB Nand,Kernel:2.6.30.4
  • 编译器:arm-linux-gcc-4.3.2.tgz
  • u-boot:u-boot-2009.08.tar.bz2

二、移植步骤

4)准备进入u-boot的第二阶段(在u-boot中添加对我们开发板上Nor Flash的支持)
通常,在嵌入式bootloader中,有两种方式来引导启动内核:从Nor Flash启动和从Nand Flash启动。u-boot中默认是从Nor Flash启动,再从上一节这个运行结果图中看,还发现几个问题:第一,我开发板的Nor Flash是2M的,而这里显示的是512kB;第二,出现Warning - bad CRC, using default environment的警告信息。不是u-boot默认是从Nor Flash启动的吗?为什么会有这些错误信息呢?这是因为我们还没有添加对我们自己的Nor Flash的支持,u-boot默认的是其他型号的Nor Flash,而我们的Nor Flash的型号是SST39VF1601。另外怎样将命令行提示符前面的SMDK2410变成我自己定义的呢?

下面我们一一来解决这些问题,让u-boot完全对我们Nor Flash的支持。首先我们修改头文件代码如下:

#gedit include/configs/my2440.h //修改命令行前的名字和Nor Flash参数部分的定义

#define CONFIG_SYS_PROMPT   "[MY2440]#"  //将命令行前的名字改成[MY2440]

 

/*-----------------------------------------------------------------------
 * FLASH and environment organization
 */

#if 0    
//注释掉下面两个类型的Nor Flash设置,因为不是我们所使用的型号
#define CONFIG_AMD_LV400     1 /* uncomment this if you have a LV400 flash */
#define CONFIG_AMD_LV800     1 /* uncomment this if you have a LV800 flash */
#endif

#define CONFIG_SYS_MAX_FLASH_BANKS 1  /* max number of memory banks */

#ifdef CONFIG_AMD_LV800
#define PHYS_FLASH_SIZE            0x00100000  /* 1MB */
#define CONFIG_SYS_MAX_FLASH_SECT  (19)        /* max number of sectors on one chip */
#define CONFIG_ENV_ADDR            (CONFIG_SYS_FLASH_BASE + 0x0F0000) /* addr of environment */
#endif
#ifdef CONFIG_AMD_LV400
#define PHYS_FLASH_SIZE            0x00080000  /* 512KB */
#define CONFIG_SYS_MAX_FLASH_SECT  (11)        /* max number of sectors on one chip */
#define CONFIG_ENV_ADDR            (CONFIG_SYS_FLASH_BASE + 0x070000) /* addr of environment */
#endif
#define CONFIG_SST_39VF1601        1        
//添加mini2440开发板Nor Flash设置
#define PHYS_FLASH_SIZE            0x200000 //我们开发板的Nor Flash是2M
#define CONFIG_SYS_MAX_FLASH_SECT  (512)    //根据SST39VF1601的芯片手册描述,对其进行操作有两种方式:块方式和扇区方式。现采用扇区方式(sector),1 sector = 2Kword = 4Kbyte,所以2M的Nor Flash共有512个sector
#define CONFIG_ENV_ADDR            (CONFIG_SYS_FLASH_BASE + 0x040000) //暂设置环境变量的首地址为0x040000(即:256Kb)

 

然后添加对我们mini2440开发板上2M的Nor Flash(型号为SST39VF1601)的支持。在u-boot中对Nor Flash的操作分别有初始化、擦除和写入,所以我们主要修改与硬件密切相关的三个函数flash_init、flash_erase、write_hword,修改代码如下:

#gedit board/samsung/my2440/flash.c

//修改定义部分如下:

//#define MAIN_SECT_SIZE   0x10000
#define MAIN_SECT_SIZE     0x1000
  //定义为4k,刚好是一个扇区的大小

//#define MEM_FLASH_ADDR1  (*(volatile u16 *)(CONFIG_SYS_FLASH_BASE + (0x00000555 << 1)))
//#define MEM_FLASH_ADDR2  (*(volatile u16 *)(CONFIG_SYS_FLASH_BASE + (0x000002AA << 1)))
#define MEM_FLASH_ADDR1    (*(volatile u16 *)(CONFIG_SYS_FLASH_BASE + (0x00005555 << 1)) //这两个参数看SST39VF1601手册      

#define MEM_FLASH_ADDR2    (*(volatile u16 *)(CONFIG_SYS_FLASH_BASE + (0x00002AAA << 1)))

 

//修改flash_init函数如下:
#elif defined(CONFIG_AMD_LV800)
            (AMD_MANUFACT & FLASH_VENDMASK) |
            (AMD_ID_LV800B & FLASH_TYPEMASK);
#elif defined(CONFIG_SST_39VF1601)   //在CONFIG_AMD_LV800后面添加CONFIG_SST_39VF1601         

            (SST_MANUFACT & FLASH_VENDMASK) |
            (SST_ID_xF1601 & FLASH_TYPEMASK)
;

for (j = 0; j < flash_info[i].sector_count; j++) {
    
//if (j <= 3) {
    
//    /* 1st one is 16 KB */
    
//    if (j == 0) {
    
//        flash_info[i].start[j] = flashbase + 0;
    
//    }

    
//    /* 2nd and 3rd are both 8 KB */
    
//    if ((j == 1) || (j == 2)) {
    
//        flash_info[i].start[j] = flashbase + 0x4000 + (j - 1) * 0x2000;
    
//    }

    
//    /* 4th 32 KB */
    
//    if (j == 3) {
    
//        flash_info[i].start[j] = flashbase + 0x8000;
    
//    }
    
//} else {
    
//    flash_info[i].start[j] = flashbase + (j - 3) * MAIN_SECT_SIZE;
    
//}

    flash_info[i].start[j] = flashbase + j * MAIN_SECT_SIZE;

}

 

//修改flash_print_info函数如下:   

case (AMD_MANUFACT & FLASH_VENDMASK):
    printf ("AMD: ");
    break;
case (SST_MANUFACT & FLASH_VENDMASK):    
//添加SST39VF1601的
    printf ("SST: ");
    break;

case (AMD_ID_LV800B & FLASH_TYPEMASK):
    printf ("1x Amd29LV800BB (8Mbit)\n");
    break;
case (SST_ID_xF1601 & FLASH_TYPEMASK):   
//添加SST39VF1601的
    printf ("1x SST39VF1610 (16Mbit)\n");
    break;

 

//修改flash_erase函数如下:
//if ((info->flash_id & FLASH_VENDMASK) !=
// (AMD_MANUFACT & FLASH_VENDMASK)) {
//    return ERR_UNKNOWN_FLASH_VENDOR;
//}
if ((info->flash_id & FLASH_VENDMASK) !=

 (SST_MANUFACT & FLASH_VENDMASK)) {
    return ERR_UNKNOWN_FLASH_VENDOR;
}

///* wait until flash is ready */
//chip = 0;
//do {
//    result = *addr;
//    /* check timeout */
//    if (get_timer_masked () >
//     CONFIG_SYS_FLASH_ERASE_TOUT) {
//        MEM_FLASH_ADDR1 = CMD_READ_ARRAY;
//        chip = TMO;
//        break;
//    }

//    if (!chip
//     && (result & 0xFFFF) & BIT_ERASE_DONE)
//        chip = READY;

//    if (!chip
//     && (result & 0xFFFF) & BIT_PROGRAM_ERROR)
//        chip = ERR;
//} while (!chip);

//MEM_FLASH_ADDR1 = CMD_READ_ARRAY;

//if (chip == ERR) {
//    rc = ERR_PROG_ERROR;
//    goto outahere;
//}

//if (chip == TMO) {
//    rc = ERR_TIMOUT;
//    goto outahere;
//}
while (1)

{
    if ((*addr & 0x40) != (*addr & 0x40))
        continue;

    if (*addr & 0x80)
    {
        rc = ERR_OK;
        break;
    }
}

 

//修改write_hword函数如下:
MEM_FLASH_ADDR1 = CMD_UNLOCK1;
MEM_FLASH_ADDR2 = CMD_UNLOCK2;
//MEM_FLASH_ADDR1 = CMD_UNLOCK_BYPASS;
MEM_FLASH_ADDR1 = CMD_PROGRAM;
   
//*addr = CMD_PROGRAM;
*addr = data;

///* wait until flash is ready */
//chip = 0;
//do {
//    result = *addr;
//    /* check timeout */
//    if (get_timer_masked () > CONFIG_SYS_FLASH_ERASE_TOUT) {
//        chip = ERR | TMO;
//        break;
//    }

//    if (!chip && ((result & 0x80) == (data & 0x80)))
//        chip = READY;

//    if (!chip && ((result & 0xFFFF) & BIT_PROGRAM_ERROR)) {
//        result = *addr;

//        if ((result & 0x80) == (data & 0x80))
//            chip = READY;
//        else
//            chip = ERR;
//    }
//} while (!chip);

//*addr = CMD_READ_ARRAY;

//if (chip == ERR || *addr != data)
//    rc = ERR_PROG_ERROR;
while (1)

{
    if ((*addr & 0x40) != (*addr & 0x40)) 
        continue;

    if ((*addr & 0x80) == (data & 0x80))
    {
        rc = ERR_OK;
        break; 
    }
}

 

 

 

 

 

修改完后重新编译u-boot,下载到RAM中运行结果如下图:

从运行结果图看,Nor Flash的大小可以正确检测到了,命令行前面的名字也由原来的SMDK2410改成我自己定义的[MY2440]了,但是还会出现bad CRC的警告信息,其实这并不是什么问题,只是还没有将环境变量设置到Nor Flash中,我们执行一下u-boot的:saveenv命令就可以了。如下图:

再重新下载u-boot.bin文件到RAM中运行,可以观察到不会出现警告信息了,这时候u-boot已经对我们开发板上的Nor Flash完全支持了。如下:

 

本文永久更新链接:http://embeddedlinux.org.cn/emb-linux/system-development/201303/16-2498.html



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