1 内核移植过程
1.1 下载linux 内核
从
下载linux-2.6.14.1 内核至home/arm/dev_home/kernel.
[root@localhost ~]#su arm
[arm@localhost ~]#cd $KERNEL
[arm@localhost kernel]#tar -xzvf linux-2.6.14.1.tar.gz
[arm@localhost kernel]# pwd
/home/arm/dev_home/kernel
[arm@localhost kernel]# cd linux-2.6.14
进入内核解压后的目录,以后示例中,只要是相对路径全部是相对于
/home/arm/dev_home/kernel/linux-2.6.14/此目录
1.2 修改 Makefile
修改内核目录树根下的的Makefile,指明交叉编译器
[arm@localhost linux-2.6.14]# vi Makefile
找到ARCH 和CROSS_COMPILE ,修改
ARCH ?= arm
CROSS_COMPILE ?= arm-linux-
然后设置你的PATH 环境变量,使其可以找到你的交叉编译工具链
[arm@localhost linux-2.6.14]# echo $PATH
----------------------- 页面 53-----------------------
/usr/local/arm/3.4.4/bin:/usr/kerberos/bin:/usr/local/bin:/usr/bin:/bin:/usr/X11R6/bin:/home/ly/bin
如果/usr/local/arm/3.4.4/bin 搜索路径, 加入下面语句在~/.bashrc 中
[arm@localhost linux-2.6.14]# vi ~/.bashrc
export PATH=/usr/local/arm/3.4.4/bin:$PATH
再重新登陆.
[arm@localhost linux-2.6.14]#su arm
1.3 设置flash 分区
此处一共要修改 3个文件,分别是:
1.3.1指明分区信息
在arch/arm/mach-s3c2410/devs.c 文件中:
[arm@localhost linux-2.6.14]$ vi arch/arm/mach-s3c2410/devs.c
添加如下内容:
#include #include #include ...
/* NAND Controller */
1.建立Nand Flash 分区表
/* 一个Nand Flash 总共64MB, 按如下大小进行分区 */
static struct mtd_partition partition_info[] ={
{ /* 1MB */
name: "bootloader",
size: 0x00100000,
offset: 0x0,
},{ /* 3MB */
name: "kernel",
size: 0x00300000,
offset: 0x00100000,
}, { /* 40MB */
name: "root",
size: 0x02800000,
offset: 0x00400000,
}, { /* 20MB */
name: "user",
size: 0x00f00000,
offset: 0x02d00000,
}
};
name: 代表分区名字
size: 代表flash 分区大小(单位:字节)
offset: 代表flash 分区的起始地址(相对于0x0 的偏移)
目标板计划分4 个区,分别存放bootloader, kernel, rootfs 以及以便以后扩展使用的用户文件系统空间。
各分区在Nand flash 中起始地址. 分区大小. 记录如下:
----------------------- 页面 54-----------------------
bootloader:
start: 0x00000000
len: 0x00100000
1MB
kernel:
start: 0x00100000
len: 0x00300000
3MB
rootfs:
start: 0x00400000
len: 0x02800000
40MB
User:
start: 0x02c00000
len: 0x01400000
20MB
2. 加入Nand Flash 分区
struct s3c2410_nand_set nandset ={
nr_partitions: 4, /* the number of partitions */
partitions: partition_info, /* partition table */
};
nr_partitions: 指明partition_info 中定义的分区数目
partitions: 分区信息表
3. 建立Nand Flash 芯片支持
struct s3c2410_platform_nand superlpplatform={
tacls:0,
twrph0:30,
twrph1:0,
sets: &nandset,
nr_sets: 1,
};
tacls, twrph0, twrph1 的意思见S3C2410 手册的6-3, 这3 个值最后会被设置到NFCONF 中,见S3C2410 手册6-6.
sets: 支持的分区集
nr_set:分区集的个数
4. 加入Nand Flash 芯片支持到Nand Flash 驱动
另外,还要修改此文件中的s3c_device_nand 结构体变量,添加对dev 成员的赋值
struct platform_device s3c_device_nand = {
.name = "s3c2410-nand", /* Device name */
.id = -1, /* Device ID */
.num_resources = ARRAY_SIZE(s3c_nand_resource),
.resource = s3c_nand_resource, /* Nand Flash Controller Registers */
/* Add the Nand Flash device */
.dev = {
.platform_data = &superlpplatform
}
};
----------------------- 页面 55-----------------------
name: 设备名称
id: 有效设备编号,如果只有唯一的一个设备为-1, 有多个设备从0 开始计数.
num_resource: 有几个寄存器区
resource: 寄存器区数组首地址
dev: 支持的Nand Flash 设备
1.3.2 指定启动时初始化
kernel 启动时依据我们对分区的设置进行初始配置
修改arch/arm/mach-s3c2410/mach-smdk2410.c 文件
[arm@localhost linux-2.6.14]$ vi arch/arm/mach-s3c2410/mach-smdk2410.c
修改smdk2410_devices[].指明初始化时包括我们在前面所设置的flash 分区信息
static struct platform_device *smdk2410_devices[] __initdata = {
&s3c_device_usb,
&s3c_device_lcd,
&s3c_device_wdt,
&s3c_device_i2c,
&s3c_device_iis,
/* 添加如下语句即可 */
&s3c_device_nand,
};
保存,退出。
1.3.3 禁止 Flash ECC校验
我们的内核都是通过UBOOT 写到Nand Flash 的, UBOOT 通过的软件ECC 算法产生ECC 校验码, 这与内核
校验的ECC 码不一样, 内核中的ECC 码是由S3C2410 中Nand Flash 控制器产生的. 所以, 我们在这里选择禁止
内核ECC 校验.
修改drivers/mtd/nand/s3c2410.c 文件:
[arm@localhost linux-2.6.14]$ vi drivers/mtd/nand/s3c2410.c
找到s3c2410_nand_init_chip()函数,在该函数体最后加上一条语句:
chip->eccmode = NAND_ECC_NONE;
保存,退出。
OK.我们的关于flash 分区的设置全部完工.
1.4 配置内核
1.4.1 支持启动时挂载 devfs
为了我们的内核支持devfs 以及在启动时并在/sbin/init 运 之前能自动挂载/dev 为devfs 文件系统,修改
fs/Kconfig 文件
[arm@localhost linux-2.6.14]$ vi fs/Kconfig
找到menu "Pseudo filesystems"
添加如下语句:
config DEVFS_FS
bool "/dev file system support (OBSOLETE)"
default y
config DEVFS_MOUNT
----------------------- 页面 56-----------------------
bool "Automatically mount at boot"
default y
depends on DEVFS_FS
1.4.2 配置内核产生.config 文件
[arm@localhost linux-2.6.14]$ cp arch/arm/configs/smdk2410_defconfig .config
[arm@localhost linux-2.6.14]$ make menuconfig
在smdk2410_defconfig 基础上,我所增删的内核配置项如下:
Loadable module support --->
[*] Enable loadable module support
[*] Automatic kernel module loading
System Type ---> [*] S3C2410 DMA support
Boot options ---> Default kernel command string:
noinitrd root=/dev/mtdblock2 init=/linuxrc console=ttySAC0,115200
#说明:mtdblock2 代表我的第3 个flash 分区,它是我的rootfs
# console=ttySAC0,115200 使kernel 启动期间的信息全部输出到串口0 上.
# 2.6 内核对于串口的命名改为ttySAC0 ,但这不影响用户空间的串口编程。
# 用户空间的串口编程针对的仍是/dev/ttyS0 等
Floating point emulation --->
[*] NWFPE math emulation
This is necessary to run most binaries!!!
#接下来要做的是对内核MTD 子系统的设置
Device Drivers --->
Memory Technology Devices (MTD) --->
[*] MTD partitioning support
#支持MTD 分区,这样我们在前面设置的分区才有意义
[*] Command line partition table parsing
#支持从命令行设置flash 分区信息,灵活
RAM/ROM/Flash chip drivers --->
Detect flash chips by Common Flash
Interface (CFI) probe
Detect non-CFI AMD/JEDEC-compatible flash chips
Support for Intel/Sharp flash chips
Support for AMD/Fujitsu flash chips
Support for ROM chips in bus mapping
NAND Flash Device Drivers --->
NAND Device Support
NAND Flash support for S3C2410/S3C2440 SoC
Character devices --->
[*] Non-standard serial port support
[*] S3C2410 RTC Driver
#接下来做的是针对文件系统的设置,本人实验时目标板上要上的文件系统是cramfs,故做如下配置
----------------------- 页面 57-----------------------
File systems --->
<> Second extended fs support #去除对ext2 的支持
Pseudo filesystems --->
[*] /proc file system support
[*] Virtual memory file system support (former shm fs)
[*] /dev file system support (OBSOLETE)
[*] Automatically mount at boot (NEW)
#这里会看到我们前先修改fs/Kconfig 的成果,devfs 已经被支持上了
Miscellaneous filesystems --->
Compressed ROM file system support (cramfs)
#支持cramfs
Network File Systems --->
NFS file system support
保存退出,产生.config 文件.
.config 文件能从提供的2.4.14.1 的内核包中找到,文件名为config.back.
1.4.3编译内核
[arm@localhost linux-2.6.14]$ make zImage
注意:若编译内核出现如下情况
LD .tmp_vmlinux1
arm-linux-ld:arch/arm/kernel/vmlinux.lds:1439: parse error
make: *** [.tmp_vmlinux1] Error 1
解决方法:修改arch/arm/kernel/vmlinux.lds
[arm@localhost linux-2.6.14]$ vi arch/arm/kernel/vmlinux.lds
将文件尾2 条的ASSERT 注释掉 (1439 )
/* ASSERT((__proc_info_end - __proc_info_begin), "missing CPU support") */
/* ASSERT((__arch_info_end - __arch_info_begin), "no machine record defined") */
然后重新make zImage 即可
1.4.4 下载zImage到开发板
CRANE2410 # tftp 0x30008000 zImage
TFTP from server 192.168.1.6; our IP address is 192.168.1.5
Filename 'zImage'.
Load address: 0x30008000
Loading: #################################################################
#################################################################
#################################################################
#############################
done
Bytes transferred = 1142856 (117048 hex)
CRANE2410 # bootm 0x30008000
1.4.5 目标板启动信息如下
IRQ Stack: 33fc149c
FIQ Stack: 33fc249c
1
----------------------- 页面 58-----------------------
1
DRAM Configuration:
Bank #0: 30000000 64 MB
1
NAND:64 MB
In: serial
Out: serial
Err: serial
Hit any key to stop autoboot: 0
zImage magic = 0x016f2818
NOW, Booting Linux......
Uncompressing
Linux............................................................................
don.Linux version 2.6.14.1 (arm@dozec) (gcc
version 3.3.2) #15 Thu Jul 6 14:26:29 CST 2006
CPU: ARM920Tid(wb) [41129200] revision 0 (ARMv4T)
Machine: SMDK2410
Warning: bad configuration page, trying to continue
Memory policy: ECC disabled, Data cache writeback
CPU S3C2410A (id 0x32410002)
S3C2410: core 202.800 MHz, memory 101.400 MHz, peripheral 50.700 MHz
S3C2410 Clocks, (c) 2004 Simtec Electronics
CLOCK: Slow mode (1.500 MHz), fast, MPLL on, UPLL on
CPU0: D VIVT write-back cache
CPU0: I cache: 16384 bytes, associativity 64, 32 byte lines, 8 sets
CPU0: D cache: 16384 bytes, associativity 64, 32 byte lines, 8 sets
Built 1 zonelists
Kernel command line: noinitrd root=/dev/mtdblock2 init=/linuxrc console=ttySAC0,115200
irq: clearing subpending status 00000002
PID hash table entries: 128 (order: 7, 2048 bytes)
timer tcon=00500000, tcnt a509, tcfg 00000200,00000000, usec 00001e4c
Console: colour dummy device 80x30
Dentry cache hash table entries: 4096 (order: 2, 16384 bytes)
Inode-cache hash table entries: 2048 (order: 1, 8192 bytes)
Memory: 16MB = 16MB total
Memory: 13712KB available (1927K code, 422K data, 104K init)
Mount-cache hash table entries: 512
CPU: Testing write buffer coherency: ok
softlockup thread 0 started up.
NET: Registered protocol family 16
S3C2410: Initialising architecture
SCSI subsystem initialized
usbcore: registered new driver usbfs
usbcore: registered new driver hub
S3C2410 DMA Driver, (c) 2003-2004 Simtec Electronics
DMA channel 0 at c1800000, irq 33
DMA channel 1 at c1800040, irq 34
DMA channel 2 at c1800080, irq 35
DMA channel 3 at c18000c0, irq 36
NetWinder Floating Point Emulator V0.97 (double precision)
devfs: 2004-01-31 Richard Gooch ([email protected])
devfs: boot_options: 0x1
Console: switching to colour frame buffer device 80x25
fb0: Virtual frame buffer device, using 1024K of video memory
----------------------- 页面 59-----------------------
S3C2410 RTC, (c) 2004 Simtec Electronics
s3c2410_serial0 at MMIO 0x50000000 (irq = 70) is a S3C2410
s3c2410_serial1 at MMIO 0x50004000 (irq = 73) is a S3C2410
s3c2410_serial2 at MMIO 0x50008000 (irq = 76) is a S3C2410
io scheduler noop registered
io scheduler anticipatory registered
io scheduler deadline registered
io scheduler cfq registered
RAMDISK driver initialized: 16 RAM disks of 4096K size 1024 blocksize
Cirrus Logic CS8900A driver for Linux (Modified for SMDK2410)
eth0: CS8900A rev E at 0xe0000300 irq=53, no eeprom , addr: 08: 0:3E:26:0A:5B
S3C24XX NAND Driver, (c) 2004 Simtec Electronics
s3c2410-nand: mapped registers at c1980000
s3c2410-nand: timing: Tacls 10ns, Twrph0 30ns, Twrph1 10ns
NAND device: Manufacturer ID: 0xec, Chip ID: 0x76 (Samsung NAND 64MiB 3,3V 8-bit)
NAND_ECC_NONE selected by board driver. This is not recommended !!
Scanning device for bad blocks
Creating 4 MTD partitions on "NAND 64MiB 3,3V 8-bit":
0x00000000-0x00100000 : "bootloader"
0x00100000-0x00500000 : "kernel"
0x00500000-0x02d00000 : "root"
0x02d00000-0x03c00000 : "User"
usbmon: debugfs is not available
116x: driver isp116x-hcd, 05 Aug 2005
s3c2410-ohci s3c2410-ohci: S3C24XX OHCI
s3c2410-ohci s3c2410-ohci: new USB bus registered, assigned bus number 1
s3c2410-ohci s3c2410-ohci: irq 42, io mem 0x49000000
usb usb1: Product: S3C24XX OHCI
usb usb1: Manufacturer: Linux 2.6.14.1 ohci_hcd
usb usb1: SerialNumber: s3c24xx
hub 1-0:1.0: USB hub found
hub 1-0:1.0: 2 ports detected
sl811: driver sl811-hcd, 19 May 2005
usbcore: registered new driver cdc_acm
drivers/usb/class/cdc-acm.c: v0.23:USB Abstract Control Model driver for USB modems and ISDN
adaptesdrivers/usb/class/bluetty.c: USB Bluetooth support registered
usbcore: registered new driver bluetty
drivers/usb/class/bluetty.c: USB Bluetooth tty driver v0.13
usbcore: registered new driver usblp
drivers/usb/class/usblp.c: v0.13: USB Printer Device Class driver
Initializing USB Mass Storage driver...
usbcore: registered new driver usb-storage
USB Mass Storage support registered.
mice: PS/2 mouse device common for all mice
NET: Registered protocol family 2
IP route cache hash table entries: 256 (order: -2, 1024 bytes)
TCP established hash table entries: 1024 (order: 0, 4096 bytes)
TCP bind hash table entries: 1024 (order: 0, 4096 bytes)
TCP: Hash tables configured (established 1024 bind 1024)
TCP reno registered
TCP bic registered
NET: Registered protocol family 1
----------------------- 页面 60-----------------------
NET: Registered protocol family 17
Reading data from NAND FLASH without ECC is not recommended
VFS: Mounted root (cramfs filesystem) readonly.
Mounted devfs on /dev
Freeing init memory: 104K
Reading data from NAND FLASH without ECC is not recommended
mount /etc as ramfs
re-create the /etc/mtab entries
------------mount /dev/shm as tmpfs
------------mount /proc as proc
------------mount /sys as sysfs
init started: BusyBox v1.1.3 (2006.07.03-03:43+0000) multi-call binary
Starting pid 28, console /dev/tts/0: '/etc/init.d/rcS'
in /etc/init.d/rcS
-------------/sbin/ifconfig eth0 192.168.1.5
Please press Enter to activate this console.
#
1.5 Linux 下cs8900a 的移植说明
1.5.1 为 cs8900a建立编译菜单
1. 拷贝到文件
把cs8900a 的压缩包拷贝到arm 用户下的dev_home/localapps/
[arm@localhost localapps]$ tar -xzvf cs8900a.tar.gz
[arm@localhost localapps]$cd cs8900a
[arm@localhost cs8900a]$cp cs8900a.c $KERNEL/linux-2.6.14.1/drivers/net/
[arm@localhost cs8900a]$cp cs8900.h $KERNEL/linux-2.6.14.1/drivers/net/
2. 修改Kconfig 文件
[arm@localhost cs8900a]$vi $KERNEL/linux-2.6.14.1/drivers/net/Kconfig
#加入如下内容
config CS8900a
tristate "CS8900a support"
depends on NET_ETHERNET && ARM && ARCH_SMDK2410
---help---
Support for CS8900A chipset based Ethernet cards. If you have a network (Ether
net) card of this type, say Y and read the Ethernet-HOWTO, available from as
well as.
To compile this driver as a module, choose M here and read.
The module will be called cs8900.o.
3. 修改Makefile 文件
[arm@localhost cs8900a]$vi $KERNEL/linux-2.6.14.1/drivers/net/Makefile
#加入如下内容
obj-$(CONFIG_CS8900a) += cs8900a.o
1.5.2 修改 S3C2410相关信息
1. 加入CS8900A 在内存中的起始位置
----------------------- 页面 61-----------------------
[arm@localhost cs8900a]$cp reg-cs8900.h $KERNEL/linux-2.6.14.1/include/asm-arm/arch-s3c2410/
cs8900.h 的内容如下:
#ifndef _INCLUDE_CS8900A_H_
#define _INCLUDE_CS8900A_H_
#include #define pSMDK2410_ETH_IO 0x19000000 /* S3C2410_CS3 0x18000000 */
#define vSMDK2410_ETH_IO 0xE0000000
#define SMDK2410_ETH_IRQ IRQ_EINT9
#endif
2. 加入cs8900A 的物理地址到虚拟地址的映射
[arm@localhost cs8900a]$vi $KERNEL/linux-2.6.14.1/arch/arm/mach-s3c2410/mach-smdk2410.c
/* 加入如下内容 */
static struct map_desc smdk2410_iodesc[] __initdata = {
{vSMDK2410_ETH_IO, 0x19000000, SZ_1M, MT_DEVICE} /* Add this line */
};
2 创建 uImage
2.1 相关技术背景介绍
前面已经介绍了内核编译后,生成zImage 的内核镜像文件。该镜像文件可以通过U-BOOT 提供的go 命令,
跳转执行,引导内核。同时在u-boot-1.1.4 的tools 目录下,提供了生成uImage 的工具mkimage 命令,在生成
u-boot 的二进制镜像文件的同时,mkimage 命令会同时编译生成,无需另外编译。通过mkimage 命令,在
zImage 中加入头文件 (镜像头长0x40,真正的内核入口向后偏移了0x40 大小),生成uImage 镜像文件,该文
件就是执 bootm 所需的内核镜像文件。
2.2 在内核中创建 uImage 的方法
2.2.1 获取 mkimage工具
2.6 内核树的Makefile 提供了创建uImage 的方法,但需要我们提供相应的mkimage 命令。
所以首先拷贝u-boot 中tools 目录下编译后生成的mkimage 到/usr/bin/下,然后便可以在内核根目录下通过
make uImage
来创建uImage 文件。该文件生成在arch/arm/boot/下。
2.2.2 修改内核的 Makefile文件
[arm@localhost linux-2.6.14.1]$ vi arch/arm/boot/Makefile
#MKIMAGE 变量记录mkimage 命令的路径mkuboot.sh 脚本文件可以scripts 目录中找到
MKIMAGE := $(srctree)/scripts/mkuboot.sh
#zreladdr-y 与params_phys-y 可以在arch/arm/mach-s3c2410/Makefile.boot 当中找到
ZRELADDR := $(zreladdr-y)
PARAMS_PHYS := $(params_phys-y)
INITRD_PHYS := $(initrd_phys-y)
----------------------- 页面 62-----------------------
#生成uImage 的mkImage 命令行,其中需要关注的就是-a 与 -e 参数。
#参数-a:指明uImage 加载的SDRAM 地址,内核默认指定加载地址为0x30008000 。
# u-boot 引导时,bootm 命令跳到与上相同位置执行,检查完镜像头后,它会跳到内核真正的入口点开
始执 。
#参数-e:指明uImage 中刨去镜像头后真正的内核入口地址。
# 镜像头为0x40 长,故此处指定为0x30008040 。
# u-boot 引导时,go 命令可以直接指定此位置。go 命令不检查镜像头。
quiet_cmd_uimage = UIMAGE $@
cmd_uimage = $(CONFIG_SHELL) $(MKIMAGE) -A arm -O linux -T kernel \
-C none -a $(ZRELADDR) -e 0x30008040 \
-n 'Linux-$(KERNELRELEASE)' -d $< $@
3追加实验记录
以同样方式移植其他2.6 主线内核,出现问题如下:
3.1移植 linux-2.6.15.7
编译通过,启动时显示:
VFS: Cannot open root device "mtdblock2" or unknown-block(31,2)
Please append a correct "root=" boot option
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(31,2)
3.2 移植 linux-2.6.16.21
编译通过,启动时显示:
VFS: Cannot open root device "mtdblock2" or unknown-block(31,2)
Please append a correct "root=" boot option
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(31,2)
3.3 移植 linux-2.6.17
编译失败
4 参考资料
1. Porting kernel 2.6.11.7 to S3C2410
http://superlp.blogchina.com/1391393.html
非常感谢此篇文档的作者
2. devfs 介绍
http://www-128.ibm.com/developerworks/cn/linux/filesystem/l-fs4/index.html#resources
3. <>
中文名:<>
作者介绍:本文由尚观科技老师和同学生(刘勇,孙贺,聂强,聂大鹏 ,牛须乐,孙磊)共同创作