嵌入式Linux之我行，主要讲述和总结了本人在学习嵌入式linux中的每个步骤。一为总结经验，二希望能给想入门嵌入式Linux的朋友提供方便。如有错误之处，谢请指正。
一、移植环境
二、移植步骤上接：u-boot-2009.08在2440上的移植详解（一）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.start[j] =
flashbase + 0;
// }
// /* 2nd and 3rd are both 8 KB */
// if ((j == 1) || (j == 2)) {
// flash_info.start[j] =
flashbase + 0x4000 + (j -
1) *
0x2000;
// }
// /* 4th 32 KB */
// if (j == 3) {
// flash_info.start[j] =
flashbase + 0x8000;
// }
//} else {
// flash_info.start[j] =
flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
}flashbase + 0x8000;
// }
//} else {
// flash_info.start[j] =
flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
}flashbase + 0x8000;
// }
//} else {
// flash_info.start[j] =
flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
}flashbase + 0x4000 + (j -
1) *
0x2000;
// }
// /* 4th 32 KB */
// if (j == 3) {
// flash_info.start[j] =
flashbase + 0x8000;
// }
//} else {
// flash_info.start[j] =
flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
}flashbase + 0x8000;
// }
//} else {
// flash_info.start[j] =
flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
}flashbase + 0x8000;
// }
//} else {
// flash_info.start[j] =
flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
}flashbase + 0x4000 + (j -
1) *
0x2000;
// }
// /* 4th 32 KB */
// if (j == 3) {
// flash_info.start[j] =
flashbase + 0x8000;
// }
//} else {
// flash_info.start[j] =
flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
}flashbase + 0x8000;
// }
//} else {
// flash_info.start[j] =
flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
}flashbase + 0x8000;
// }
//} else {
// flash_info.start[j] =
flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
}flashbase + 0;
// }
// /* 2nd and 3rd are both 8 KB */
// if ((j == 1) || (j == 2)) {
// flash_info.start[j] =
flashbase + 0x4000 + (j -
1) *
0x2000;
// }
// /* 4th 32 KB */
// if (j == 3) {
// flash_info.start[j] =
flashbase + 0x8000;
// }
//} else {
// flash_info.start[j] =
flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
}flashbase + 0x8000;
// }
//} else {
// flash_info.start[j] =
flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
}flashbase + 0x8000;
// }
//} else {
// flash_info.start[j] =
flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+ j
* MAIN_SECT_SIZE;
} flashbase + (j - 3) * MAIN_SECT_SIZE;
//}
flash_info[i.start[j
= flashbase
+
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