一、下载linux-2.6.30.4源码,并解压

ftp://ftp.kernel.org/pub/linux/kernel/v2.6/linux-2.6.30.4.tar.gz

tar zxvf linux-2.6.30.4.tar.gz

二、在系统中添加对ARM的支持

$vim Makefile

193#ARCH ?= $(SUBARCH)

 194#CROSS_COMPILE ?=

 195 ARCH=arm

 196 CROSS_COMPILE=arm-linux-

三、修改系统时钟

$vim arch/arm/mach-s3c2440/mach-smdk2440.c

系统的外部时钟为12MHz

 160static void __init smdk2440_map_io(void)

 161{

 162s3c24xx_init_io(smdk2440_iodesc,ARRAY_SIZE(smdk2440_iodesc));

 163//s3c24xx_init_clocks(16934400);

 164//edit by

 165 s3c24xx_init_clocks(12000000);

 166s3c24xx_init_uarts(smdk2440_uartcfgs,ARRAY_SIZE(smdk2440_uartcfgs));

 167}

说明:如果系统时钟不匹配,则出现乱码。

四、制作或者获取内核配置单.config

$make menuconfig

说明:一个比较好的做法是先调用自带的配置清单,该配置清单在arch/arm/configs目录,文件名为:s3c2410_defconfig,该配置文件几乎S3C24XX系列CPU的配置项,可以在此基础上修改配置项。x86的配置项在arch/x86/configs目录下,文件名为:i386_defconfig(32为cpu)。

cp arch/arm/configs/s3c2410_defconfig .config

五、修改机器码

【linux内核源码中查看机器码相关文件:】

$vim arch/arm/mach-s3c2440/mach-smdk2440.c

178 MACHINE_START(S3C2440 , "SMDK2440")

 179/* Maintainer: Ben Dooks <ben@fluff.org> */

 180.phys_io = S3C2410_PA_UART,

 181.io_pg_offst = (((u32)S3C24XX_VA_UART)>> 18) & 0xfffc,

 182.boot_params = S3C2410_SDRAM_PA+ 0x100,

 183

184 .init_irq = s3c24xx_init_irq,

 185.map_io = smdk2440_map_io,

 186.init_machine = smdk2440_machine_init,

 187.timer = &s3c24xx_timer,

 188MACHINE_END

 

修改机器码,使之与bootloader的机器码相同,这里使用的是u-boot,机器码为168

$vim arch/arm/tools/mach-types

379 s3c2440 ARCH_S3C2440 S3C2440168

$vim arch/arm/tools/Makefile

7 include/asm-arm/mach-types.h :$(src)/gen-mach-types $(src)/mach-types

 8@echo ' Generating $@'

 9@mkdir -p $(dir $@)

 10$(Q)$(AWK) -f $^ > $@ || { rm -f $@; /bin/false; }

$vim include/asm/mach-types.h

375 #define MACH_TYPE_S3C2440168 //这个没有找见

 

【U-boot中的相关配置文件】

$vim include/asm-arm/mach-types.h

377 #define MACH_TYPE_S3C2440 168

总结:首先从linux内核源码中找出机器类型(如S3C2440 ),其次,根据u-boot中给出的对应机器类型的机器码(如377 #define MACH_TYPE_S3C2440 168 )修改内核机器码。流程如下:

 内核:

 $vimarch/arm/mach-s3c2440/mach-smdk2440.c

U-boot:

 $viminclude/asm-arm/mach-types.h

内核:

 $vimarch/arm/tools/mach-types

说明:如果机器码错误,则系统提示选取平台,死机。

六、编译镜像

$make zImage

 

七、板子烧写

使用DNW工具将内核镜像烧写至开发板中

八、遇到的问题

问题:

 Kernel panic - not syncing: Attempted to killinit!

解决办法:

 $make menuconfig

选择以下两项:

 Kernel Features --->

[*] Use the ARM EABI to compile the kernel

[*] Allow old ABI binaries to run with thiskernel (EXPERIMENTAL)

九、NandFlash驱动移植

linux里面已经包含NandFlash驱动,只需对源码进行修改即可。

1、$vim arch/arm/plat-s3c24xx/common-smdk.c

107 /* NAND parititon from 2.4.18-swl5*/

 108

109 static struct mtd_partitionsmdk_default_nand_part[] = {

 110#if defined(CONFIG_64MB_NAND )

111 [0] = {

 112.name = "Board_uboot",

 113.size = 0x00040000,

 114.offset = 0x00000000,

 115},

 116[1] = {

 117.name = "Board_kernel",

 118.size        = 0x00200000,

 119.offset= 0x00200000,

 120},

 121[2] = {

 122.name = "Board_yaffs2",

 123.size = 0x03BF8000,

 124.offset = 0x00400000,

 125}

 126#elif defined(CONFIG_128MB_NAND)

127 [0]={

 128.name ="Board_uboot",

 129.offset =0x00000000,

 130.size =0x00040000,

 131},

 132[1]={

 133.name ="Board_kernel",

 134.offset =0x00200000,

 135.size =0x00200000,

 136},

 137[2]={

 138.name ="Board_yaffs2"

 139.offset =0x00400000,

 140.size =0x07BA0000,

 141}

142 #elif defined(CONFIG_more_than_256MB_NAND)

143 [0]={

 144.name ="Board_uboot",

 145.offset =0x00000000,

 146.size =0x00040000,

 147},

 148[1]={

 149.name ="Board_kernel",

 150.offset =0x00200000,

 151.size =0x00200000,

 152},

 153[2]={

 154.name ="Board_yaffs2",

 155.offset =0x00400000,

 156.size =0x0FB80000,

 157}

 158#endif

 159};

2、$vimdrivers/mtd/nand/Kconfig

166 choice

 167prompt "Nand Flash Capacity select"

 168depends on MTD

 169help

 170Board Nand Flash Capacity select

 171

172 config 64MB_NAND

173 boolean "64MB Nand for Board"

 174depends on MTD

 175help

 176Set 64MB Nand parts

 177

178 config 128MB_NAND

 179boolean "128MB Nand for Board"

 180depends on MTD

 181help

 182Set 128MB Nand parts

 183

184 config more_than_256MB_NAND

 185boolean "256MB~1GB Nand for Board"

 186depends on MTD

 187help

 188Set 256MB~1GB Nand parts

 189

190 endchoice

 注:如果在make menuconfig中选中64MB_NAND,则在.config表现形式如下:

 CONFIG _64MB_NAND=y

这实际是给C源文件提供预编译变量,如#if defined(CONFIG_64MB_NAND).......

这个过程就是实现了内核的定制,比如新增Nand驱动、或者去除wireless驱动。。。

十、移植yaffs2文件系统

1、获取yaffs2源码

http://www.aleph1.co.uk/cgi-bin/viewcvs.cgi/

www.aleph1.co.uk/home/aleph1/git/yaffs2

2、在内核中添加对yaffs2的支持

在刚下载的yaffs2源码中,执行:

 ./patch-ker.sh c ../linux-2.6.30.4(两个文件夹放一起)

此时在内核fs目录下,新增“yaffs2”目录,同时fs/目录下面的Makefile文件和Kconfig文件也添加了yaffs2的配置和编译条件。

3、在配置单中添加对yaffs2的支持

$make menuconfig

File systems --->

 [*]Miscellaneous filesystems --->

 <*> YAFFS2 file system support

 注意:假如在内核中没有添加对yaffs2的支持,则出现找不到或者挂载文件系统是失败的提示:

 Listof all partitions:

 01004096 ram0 (driver?)

 01014096 ram1 (driver?)

 01024096 ram2 (driver?)

 01034096 ram3 (driver?)

 01044096 ram4 (driver?)

 01054096 ram5 (driver?)

 01064096 ram6 (driver?)

 01074096 ram7 (driver?)

 01084096 ram8 (driver?)

 01094096 ram9 (driver?)

 010a 4096 ram10 (driver?)

 010b4096 ram11 (driver?)

 010c 4096 ram12 (driver?)

 010d4096 ram13 (driver?)

 010e4096 ram14 (driver?)

 010f 4096 ram15 (driver?)

 1f00 256 mtdblock0 (driver?)

 1f01 2048 mtdblock1 (driver?)

 1f02 63168 mtdblock2 (driver?)

 Nofilesystem could mount root, tried: ext3 ext2 cramfs msdos vfat romfs

 Kernel panic - not syncing: VFS: Unable tomount root fs on unknown-block(31,2)

4、yaffs2移植完成,重新编译内核

十一、在内核中添加tmpfs支持

如果不添加tmpfs支持,那么将会出现那/tmp挂载失败的提示。关于tmpfs的作用待研究。

 mount: mounting tmpfs on /tmp failed: Invalidargume

文件系统配置:

 [root@ /]#cat /etc/fstab

 proc /proc proc defaults 0 0

 tmpfs /tmp tmpfs defaults 0 0

 sysfs /sys sysfs defaults 0 0

 tmpfs /dev tmpfs defaults 0 0

 var /dev tmpfs defaults 0 0

File systems --->

 Pseudo filesystems --->

[*] Virtual memory file system support(former shm fs)

 [*]Tmpfs POSIX Access Control Lists

十二遇到的问题及解决方案

drivers/rtc/hctosys.c:unable to open rtc device (rtc0)

1.   内核配置选项


 --- Real TimeClock                                                                                        
                   [*]   Set system time from RTC on startup andresume                                                   
                    (rtc0)  RTC used to set the systemtime                                                        
                   [ ]   RTC debugsupport                                                                                   
                     *** RTC interfaces***                                                                             
                   [*]   /sys/class/rtc/rtcN(sysfs)                                                                  
                   [*]   /dev/rtcN (characterdevices)                                                                
                   [ ]     RTC UIE emulation on devinterface      
      *** on-CPU RTC drivers***                                                               
                   <*>   Samsung S3Cseries SoC RTC  

2.  linux kernel 中 已经支持S3C2410的RTC,但是并没有添加到平台设备初始化数组中,所以系统启动时并不会初始化这一部分,需要修改文件mach-smdk.c

static struct platform_device*smdk2410_devices[] __initdata = {
    &s3c_device_ohci,
    &s3c_device_lcd,
    &s3c_device_wdt,
    &s3c_device_i2c0,
    &s3c_device_iis,
    &s3c_device_rtc,   //新增代码
};

3.  创建设备节点,在文件系统/dev目录下执行:

sudo   mknod rtc c 10 135

4.  重新编译内核,查看启动信息

s3c2410-rtcs3c2410-rtc: rtc disabled,re-enabling

s3c2410-rtcs3c2410-rtc: rtc core:registered s3c asrtc0

这里说明rtc驱动起来可以正常工作了                          

uncorrectable error :<3>end_request: I/O error, dev mtdblock2, sector 2

EXT3-fs: unable to readsuperblock

uncorrectable error :<3>end_request: I/O error, dev mtdblock2, sector 2

EXT2-fs: unable to readsuperblock

uncorrectable error :<3>end_request: I/O error, dev mtdblock2, sector 0

Buffer I/O error ondevice mtdblock2, logical block 0

uncorrectable error :<3>end_request: I/O error, dev mtdblock2, sector 0

Buffer I/O error ondevice mtdblock2, logical block 0

uncorrectable error :<3>end_request: I/O error, dev mtdblock2, sector 8

Buffer I/O error ondevice mtdblock2, logical block 1

uncorrectable error :<3>end_request: I/O error, dev mtdblock2, sector 8

Buffer I/O error ondevice mtdblock2, logical block 1

uncorrectable error :<3>end_request: I/O error, dev mtdblock2, sector 16

Buffer I/O error ondevice mtdblock2, logical block 2

uncorrectable error :<3>end_request: I/O error, dev mtdblock2, sector 16

Buffer I/O error ondevice mtdblock2, logical block 2

uncorrectable error :<3>end_request: I/O error, dev mtdblock2, sector 24

Buffer I/O error ondevice mtdblock2, logical block 3

uncorrectable error :<3>end_request: I/O error, dev mtdblock2, sector 24

Buffer I/O error ondevice mtdblock2, logical block 3

uncorrectable error :<3>end_request: I/O error, dev mtdblock2, sector 0

FAT: unable to read bootsector

VFS: Cannot open rootdevice "mtdblock2" or unknown-block(31,2)

Please append a correct"root=" boot option; here are the available partitions:

1f00             256 mtdblock0 (driver?)

1f01            2048 mtdblock1 (driver?)

1f02          257536 mtdblock2 (driver?)

Kernel panic - notsyncing: VFS: Unable to mount root fs on unknown-block(31,2)

MTD分区与bootloader不匹配

#elif defined(CONFIG_more_than_256MB_NAND)

       [0]= {

              .name      = "Board_uboot",

              .offset     = 0x00000000,

              .size = 0x00080000,

       },

       [1]= {

              .name      = "Board_kernel",

              .offset= 0x00240000,

              .size = 0x00200000,

       },

       [2]= {

              .name      = "Board_yaffs2",

              .offset= 0x00440000,

              .size = 0x0FB40000,

       }

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

 

[0]和[1]分区不连贯的表面原因   中间的部分存放uboot的参数以及开机画面??? 环境变量

uboot分区信息:

0x0      到0x40000  为uboot的分区,256K,
0x40000  到0x4c000   为parameters分区,48K,
0x50000  到0x70000   为eboot分区,128K,
0x70000  到0x1F0000  为logo分区,1536K,
0x1F0000 到0x3F0000  为kernel分区,2M,
0x3F0000 到0x3FF8000 为root分区,60.03125M


nand分区信息:

static struct mtd_partition smdk_default_nand_part[] = {
        [0] = {
                .name       = "TQ2440_uboot",
                .size       = 0x00040000,
                .offset       = 0x00000000,
        },
        [1] = {
                .name       = "TQ2440_kernel",
                .offset       = 0x0004C000,
                .size       = 0x00200000,
        },
        [2] = {
                .name       = "TQ2440_yaffs2",
                .offset       = 0x0024C000,
                .size       = 0x03DB0000,
        }
};

uboot的分区和文件系统的分区,没有联系的。唯一的联系就是uboot引导启动的时候,命令要根据文件系统的分区信息来引导。比如要从mtdblock2启动,那么bootcmd中的命令bootm0xXXXXXXX就要和mtdblock2的首地址一样。。。。