内核移植过程
下载 linux 内核
从 http://www.kernel.org/pub/linux/kernel/v2.6/linux2.6.14.1.tar.bz2
下载 linux2.6.14.1 内核至 home/arm/dev_home/kernel. [root@localhost ~]#su arm
[arm@localhost ~]#cd $KERNEL
[arm@localhost kernel]#tar xzvf linux2.6.14.1.tar.gz [arm@localhost kernel]# pwd
/home/arm/dev_home/kernel [arm@localhost kernel]# cd linux2.6.14
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/linux2.6.14/此目录
修改 Makefile
修改内核目录树根下的的 Makefile,指明交叉编译器 [arm@localhost linux2.6.14]# vi Makefile 找到 ARCH 和 CROSS_COMPILE，修改
ARCH ?= arm CROSS_COMPILE ?= armlinux
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 linux2.6.14]# echo $PATH
/usr/local/arm/3.4.4/bin:/usr/kerberos/bin:/usr/local/bin:/usr/bin:/bin:/usr/X11R6/bin:/home/ly/bin
如果/usr/local/arm/3.4.4/bin 搜索路径, 加入下面语句在~/.bashrc 中
[arm@localhost linux2.6.14]# vi ~/.bashrc export PATH=/usr/local/arm/3.4.4/bin:$PATH
再重新登陆.
[arm@localhost linux2.6.14]#su arm
设置 flash 分区
此处一共要修改 3 个文件，分别是:
指明分区信息
在 arch/arm/machs3c2410/devs.c 文件中:
[arm@localhost linux2.6.14]$ vi arch/arm/machs3c2410/devs.c
添加如下内容：
#include <linux/mtd/partitions.h>
#include <linux/mtd/nand.h>
#include <asm/arch/nand.h>
...
/* 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：
bootloader:
start: 0x00000000 len: 0x00100000 1MB
kernel:
rootfs:
User:
start: 0x00100000 len: 0x00300000 3MB
start: 0x00400000 len: 0x02800000 40MB
start: 0x02c00000 len: 0x01400000 20MB
- 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
- 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 63, 这 3 个值最后会被设置到 NFCONF 中,见 S3C2410 手册 66. sets: 支持的分区集
nr_set:分区集的个数
- 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 = "s3c2410nand", /* 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
}
};
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
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/machs3c2410/machsmdk2410.c 文件
[arm@localhost linux2.6.14]$ vi arch/arm/machs3c2410/machsmdk2410.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。
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 linux2.6.14]$ 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.
配置内核
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 运行之前能自动挂载/dev 为 devfs 文件系统，修改 fs/Kconfig 文件
[arm@localhost linux2.6.14]$ 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
bool "Automatically mount at boot" default y
depends on DEVFS_FS
配置内核产生.config 文件
[arm@localhost linux2.6.14]$ cp arch/arm/configs/smdk2410_defconfig .config [arm@localhost linux2.6.14]$ 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 nonCFI AMD/JEDECcompatible 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 >
[*] Nonstandard 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
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.
编译内核
[arm@localhost linux2.6.14]$ make zImage
注意：若编译内核出现如下情况
LD .tmp_vmlinux1 armlinuxld: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 linux2.6.14]$ vi arch/arm/kernel/vmlinux.lds 将文件尾 2 条的 ASSERT 注释掉（1439 行）
/* 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
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
目标板启动信息如下
IRQ Stack: 33fc149c FIQ Stack: 33fc249c 1
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 writeback 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) Inodecache hash table entries: 2048 (order: 1, 8192 bytes) Memory: 16MB = 16MB total
Memory: 13712KB available (1927K code, 422K data, 104K init) Mountcache 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) 20032004 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: 20040131 Richard Gooch (rgooch@atnf.csiro.au) devfs: boot_options: 0x1
Console: switching to colour frame buffer device 80x25
fb0: Virtual frame buffer device, using 1024K of video memory
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
s3c2410nand: mapped registers at c1980000
s3c2410nand: timing: Tacls 10ns, Twrph0 30ns, Twrph1 10ns
NAND device: Manufacturer ID: 0xec, Chip ID: 0x76 (Samsung NAND 64MiB 3,3V 8bit) 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 8bit": 0x000000000x00100000 : "bootloader" 0x001000000x00500000 : "kernel"
0x005000000x02d00000 : "root"
0x02d000000x03c00000 : "User"
usbmon: debugfs is not available
116x: driver isp116xhcd, 05 Aug 2005 s3c2410ohci s3c2410ohci: S3C24XX OHCI
s3c2410ohci s3c2410ohci: new USB bus registered, assigned bus number 1 s3c2410ohci s3c2410ohci: 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 10:1.0: USB hub found hub 10:1.0: 2 ports detected
sl811: driver sl811hcd, 19 May 2005 usbcore: registered new driver cdc_acm
drivers/usb/class/cdcacm.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 usbstorage 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
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
recreate the /etc/mtab entries
mount /dev/shm as tmpfs
mount /proc as proc
mount /sys as sysfs
init started: BusyBox v1.1.3 (2006.07.0303:43+0000) multicall 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.