嵌入式linux学习笔记（一）

最近开始学习linux驱动编写，目前直接使用jz2440已移植好的系统配合视频开始学习驱动编写，但是总是出现这样那样的问题。于是决定重头开始，先自己移植内核，在开始驱动学习。

今天参照《嵌入式linux完全应用手册》进行驱动移植。

cross_compile:4.9.3（下载地址：https://launchpad.net/gcc-arm-embedded/+download）。

kernel：2.6.22.6

1、先修改顶层目录下的Makefile文件：

ARCH = arm

CROSS_COMPILE = arm-none-eabi-

2、输入make s3c2410_defconfig进行编译，在编译的过程中发生错误。

CC      fs/binfmt_aout.o
In file included from include/linux/spinlock.h:53:0,
from include/linux/module.h:9,
from fs/binfmt_aout.c:7:
fs/binfmt_aout.c: In function 'load_aout_binary':
include/linux/a.out.h:141:38: error: 'SEGMENT_SIZE' undeclared (first use in this function)
#define _N_SEGMENT_ROUND(x) ALIGN(x, SEGMENT_SIZE)
^
include/linux/kernel.h:36:37: note: in definition of macro '__ALIGN_MASK'
#define __ALIGN_MASK(x,mask) (((x)+(mask))&~(mask))
^
include/linux/a.out.h:141:29: note: in expansion of macro 'ALIGN'
#define _N_SEGMENT_ROUND(x) ALIGN(x, SEGMENT_SIZE)
^
include/linux/a.out.h:148:9: note: in expansion of macro '_N_SEGMENT_ROUND'
: (_N_SEGMENT_ROUND (_N_TXTENDADDR(x))))
^
fs/binfmt_aout.c:320:30: note: in expansion of macro 'N_DATADDR'
(current->mm->start_data = N_DATADDR(ex));
^
include/linux/a.out.h:141:38: note: each undeclared identifier is reported only once for each function it appears in
#define _N_SEGMENT_ROUND(x) ALIGN(x, SEGMENT_SIZE)
^
include/linux/kernel.h:36:37: note: in definition of macro '__ALIGN_MASK'
#define __ALIGN_MASK(x,mask) (((x)+(mask))&~(mask))
^
include/linux/a.out.h:141:29: note: in expansion of macro 'ALIGN'
#define _N_SEGMENT_ROUND(x) ALIGN(x, SEGMENT_SIZE)
^
include/linux/a.out.h:148:9: note: in expansion of macro '_N_SEGMENT_ROUND'
: (_N_SEGMENT_ROUND (_N_TXTENDADDR(x))))
^
fs/binfmt_aout.c:320:30: note: in expansion of macro 'N_DATADDR'
(current->mm->start_data = N_DATADDR(ex));
make[1]: *** [fs/binfmt_aout.o] Error 1
make: *** [fs] Error 2

SEGMENT_SIZE’ undeclared

解决方法：

修改为：

510： NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include) -Dlinux

3、修改arch/arm/mach-s3c2440/mach-s3c2440.c中的时钟初始化参数：

修改为：180 ：s3c24xx_init_clocks(12000000);

4、修改mtd分区：

/* NAND parititon from 2.4.18-swl5 */

static struct mtd_partition smdk_default_nand_part[] = {

[0] = {

.name = "Boot Agent",

.size = SZ_16K,

.offset = 0,

},

[1] = {

.name = "S3C2410 flash partition 1",

.offset = 0,

.size = SZ_2M,

},

[2] = {

.name = "S3C2410 flash partition 2",

.offset = SZ_4M,

.size = SZ_4M,

},

[3] = {

.name = "S3C2410 flash partition 3",

.offset = SZ_8M,

.size = SZ_2M,

},

[4] = {

.name = "S3C2410 flash partition 4",

.offset = SZ_1M * 10,

.size = SZ_4M,

},

[5] = {

.name = "S3C2410 flash partition 5",

.offset = SZ_1M * 14,

.size = SZ_1M * 10,

},

[6] = {

.name = "S3C2410 flash partition 6",

.offset = SZ_1M * 24,

.size = SZ_1M * 24,

},

[7] = {

.name = "S3C2410 flash partition 7",

.offset = SZ_1M * 48,

.size = SZ_16M,

}

};

由于我是用的jz2440自带的u-boot其mtd分区如下：

device nand0 <nandflash0>, # parts = 4

#: name size offset mask_flags

0: bootloader 0x00040000 0x00000000 0

1: params 0x00020000 0x00040000 0

2: kernel 0x00200000 0x00060000 0

3: root 0x0fda0000 0x00260000 0

所以，修改为：

static struct mtd_partition smdk_default_nand_part[] = {

[0] = {

.name = "bootloader",

.size = 0x00040000,

.offset = 0,

},

[1] = {

.name = "params",

.offset = 0x00040000,

.size = 0x00020000,

},

[2] = {

.name = "kernel",

.offset = 0x00060000,

.size = 0x00200000,

},

[3] = {

.name = "root",

.offset =0x00260000,

.size = 0x0fda0000,

},

};