linux_内核移植方法及错误

解决方法：把
08.05.11、<*> RAM disk support
09.27.07、<*> Compressed ROM file system support (cramfs)
1.问题一
下载内核到flash中，运行到如下即停止没有下文：
Uncompressing Linux……………………done,booting the kernel
如果是内核NAND flash分区的问题，则作如下修改：
1. 1修改文件arch/arm/mach-s3c2410/devs.c,添加如下信息：
#include <linux/mtd/partitions.h>
#include <asm/arch/nand.h>
#include <linux/mtd/nand.h>
.resource = s3c_nand_resource, /*黑体为新加内容*/
.dev = {
.platform_data=&s3c_nand_info
}
};
1.2在arch/arm/mach-s3c2410/mach-smdk2410.c文件中添加&s3c_device_nand,如下所示：
starting pid 229, tty '': '/etc/init.d/rcS'
Please press Enter to activate this console.
4.系统启动到到如下语句即停止不前，停在那里：
VFS:Mounted root (cramfs filesystem) readonly.
0x00000000-0x00040000 : "boot"
mtd: Giving out device 0 to boot
0x00040000-0x00200000 : "kernel"
mtd: Giving out device 1 to kernel
0x00200000-0x02000000 : "rootfs"
{
tacls:0,
twrph0:30,
twrph1:0,
sets:&nandset,
nr_sets:1,
};
struct platform_device s3c_device_nand={
.name="s3c2410-nand",
.id = -1,
.num_resources = ARRAY_SIZE(s3c_nand_resources),
struct s3c2410_nand_set nandset=
{
nr_partitions:5,
partitions:partition_info,
};
struct s3c2410_platform_nand s3c_nand_info=
{
tacls:0,
twrph0:30andset,
static struct mtd_partition partition_info[]=
{
{
name:"bootloader",
size:0x00040000,
offset:0,
},
{
name:"kernel",
size:0x001c0000,
offset:0x00040000,
},
{
name:"rootfs",
VFS: Cannot open root device "<NULL>" or unknown-block(2,0)
Please append a correct "root=" boot option
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(2,0)
static struct platform_device * smdk2410_device[] _initdata=
{
&s3c_device_usb,
&s3c_device_lcd,
&s3c_device_wdt,
&s3c_device_i2c,
&s3c_device_iis,
&s3c_device_nand,
或者类似的错误。
原因分析：我在这里耗了大量的时间，这种情况一般是NAND flash分区未能分正确，或者所在的分区上没有文件系统，当启动中出现类似如下信息时表明分区正确了
Scanning device for bad blocks
Creating 5 MTD partitions on "NAND 64MiB 3,3V 8-bit":
starting pid 229, tty '': '/etc/init.d/rcS'
Reading data from NAND FLASH without ECC is not recommended
the error code is:0,name=/dev/root,fs=cramfs,flags=32769
从上面看出我的文件系统放在第三个分区rootfs上，其设备号为2,启动后文件系统能挂上,如下所示
Reading data from NAND FLASH without ECC is not recommended
the error code is:0,name=/dev/root,fs=cramfs,flags=32769
Warning: unable to open an initial console.矩阵通信网－通信.IT人的精神家园8`9Pjq&_/N
!C+Q7fW ][0这个也是控制台console的问题，linux-2.6.13以后的内核都支持devfs，而之后版本的内核就把devfs这块去掉了，虽然还能在内核源码中找到对应的源码，你也可以把它加进内核，但是也不是太好用。2.6.13后的版本改为支持udev了，udev这块我也没太弄懂，正在研究。-
VFS: Mounted root (cramfs filesystem) readonly.
Freeing init memory: 104K
Reading data from NAND FLASH without ECC is not recommended
init started: BusyBox v1.10.1(2008-04-23 23:20:41 CST)
｝
在这句里面出错就会没有下文
解决办法：在配置内核时少选了几句，将如下选择全选上
Floating Point emulation
->At least one emulation must be selected:
NWFPE math emulation
Support extended precision
mtd: Giving out device 2 to rootfs
0x02000000-0x03000000 : "ext-fs1"
mtd: Giving out device 3 to ext-fs1
0x03000000-0x04000000 : "ext-fs2"
mtd: Giving out device 4 to ext-fs2
出现问题:
## Starting application at 0x30008000 ...
Uncompressing Linux.............................................................
解决方案:
setenv bootargs console=ttySAC0,115200 mem=64M;console明令在哪暂时还没解决???
size: 0x01e00000,
offset:0x00200000,
},
{
name:"ext-fs1",
size: 0x01000000,
offset:0x02000000,
},
{
name:"ext-fs2",
size: 0x01000000,
offset:0x03000000,
},
};
//以上分区和NAND flash物理分区一样，分区不一样没试过，根据自己板子情况而定
setenv
TCP cubic registered
NET: Registered protocol family 1
NET: Registered protocol family 17
Root-NFS: No NFS server available, giving up.
VFS: Unable to mount root fs via NFS, trying floppy.
VFS: Mounted root (cramfs filesystem) readonly.
Freeing init memory: 104K
Reading data from NAND FLASH without ECC is not recommended
init started: BusyBox v1.10.1(2008-04-23 23:20:41 CST)
"noinitrd root=/dev/mtdblock2 ro init=/linuxrc console=ttySAC0,115200 rootfstype=cramfs mem=64M"