嵌入式学习笔记202-Linux kernel跑起来

1. 在《嵌入式学习笔记104-uboot_1.1.6移植（4）》、《嵌入式学习笔记300-linux根文件系统搭建》uboot和根文件系统都准备好的前提下，此时的kernel已基本可以跑起来，不过还差正确的挂起文件系统，其中uboot传给kernel的挂载处是root=/dev/mtdblock2 ，而在《嵌入式学习笔记201-Linux kernel动起来》的打印分区信息是：

mtd: partition "Boot Agent" doesn‘t end on an erase block -- force read-only
0x000000000000-0x000000200000 : "S3C2410 flash partition 1"
0x000000400000-0x000000800000 : "S3C2410 flash partition 2"
0x000000800000-0x000000a00000 : "S3C2410 flash partition 3"
0x000000a00000-0x000000e00000 : "S3C2410 flash partition 4"
0x000000e00000-0x000001800000 : "S3C2410 flash partition 5"
0x000001800000-0x000003000000 : "S3C2410 flash partition 6"
0x000003000000-0x000004000000 : "S3C2410 flash partition 7"
..........................
drivers/rtc/hctosys.c: unable to open rtc device (rtc0)
List of all partitions:
1f00              16 mtdblock0 (driver?)
1f01            2048 mtdblock1 (driver?)
1f02            4096 mtdblock2 (driver?)
1f03            2048 mtdblock3 (driver?)
1f04            4096 mtdblock4 (driver?)
1f05           10240 mtdblock5 (driver?)
1f06           24576 mtdblock6 (driver?)
1f07           16384 mtdblock7 (driver?)

1. 设置正确的分区信息及nand 驱动：
   修改linux-2.6.30.4\arch\arm\plat-s3c24xx\common-smdk.c 在109左右处修改smdk_default_nand_part[]：

static struct mtd_partition smdk_default_nand_part[] = {
    [0] = {
        .name   = "uboot_1.1.6",
        .offset = 0,
        .size   = 0x40000,
    },
    [1] = {
        .name   = "Linux kernel",
        .offset = 0x200000,
        .size      = 0x300000,
    },
    [2] = {
        .name   = "file system",
        .offset = 0x500000,
        .size   = MTDPART_SIZ_FULL,
    }
};

在linux-2.6.30.4\drivers\mtd\nand\s3c2410.c 第752行修改如下：

        chip->ecc.mode      = NAND_ECC_NONE; //NAND_ECC_SOFT;

1. 添加yaffs文件系统至kernel，2.6.30.4version的linux还不support yaffs/yaffs2文件系统，而我们的根文件系统采用的是yaffs2，所以要port，最简单的办法就是打补丁，下载cvs-root.tar.gz可自行查找或到本博客查看，

 tar zxvf cvs-root.tar.gz
 cd cvs/yaffs2
 ./patch-ker.sh c /xx/xx/linux-2.6.30.4

此时在kernel的fs下会发现有个yaffs2的目录同时在fs目录下的Makefile和Kconfig也自动添加了配置yaffs2的选项。
4. 在配置单中添加nand driver和对yaffs的支持


5. 执行make all 给生成的镜像文件加头部信息最后连同uboot root_fs.bin一并烧入，最后启动的打印信息如下：

??

U-Boot 1.1.6 (May 23 2015 - 16:37:20)

DRAM:  64 MB
Flash:  2 MB
NAND:  256 MiB
*** Warning - bad CRC or NAND, using default environment

In:    serial
Out:   serial
Err:   serial
Hit any key to stop autoboot:  0 

NAND read: device 0 offset 0x200000, size 0x300000
 3145728 bytes read: OK
## Booting image at 32000000 ...
   Image Name:   linux-2.6.30.4
   Created:      2015-05-24   2:31:40 UTC
   Image Type:   ARM Linux Kernel Image (uncompressed)
   Data Size:    1934960 Bytes =  1.8 MB
   Load Address: 30008000
   Entry Point:  30008000
   Verifying Checksum ... OK
OK

Starting kernel ...

Uncompressing Linux........................................................................................................................ done, booting the kernel.
Linux version 2.6.30.4 (vedic@vedic-VirtualBox) (gcc version 4.3.3 (Sourcery G++ Lite 2009q1-176) )  Sun May 24 10:31:24 HKT 2015
CPU: ARM920T [41129200] revision 0 (ARMv4T), cr=c0007177
CPU: VIVT data cache, VIVT instruction cache
Machine: SMDK2440
Memory policy: ECC disabled, Data cache writeback
CPU S3C2440A (id 0x32440001)
S3C24XX Clocks, (c) 2004 Simtec Electronics
S3C244X: core 400.000 MHz, memory 100.000 MHz, peripheral 50.000 MHz
CLOCK: Slow mode (1.500 MHz), fast, MPLL on, UPLL on
Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 16256
Kernel command line: noinitrd root=/dev/mtdblock2 init=/linuxrc console=ttySAC0
NR_IRQS:85
irq: clearing subpending status 00000002
PID hash table entries: 256 (order: 8, 1024 bytes)
Console: colour dummy device 80x30
console [ttySAC0] enabled
Dentry cache hash table entries: 8192 (order: 3, 32768 bytes)
Inode-cache hash table entries: 4096 (order: 2, 16384 bytes)
Memory: 64MB = 64MB total
Memory: 60932KB available (3408K code, 309K data, 116K init, 0K highmem)
Calibrating delay loop... 199.47 BogoMIPS (lpj=498688)
Mount-cache hash table entries: 512
CPU: Testing write buffer coherency: ok
net_namespace: 936 bytes
NET: Registered protocol family 16
S3C Power Management, Copyright 2004 Simtec Electronics
S3C2440: Initialising architecture
S3C2440: IRQ Support
S3C24XX DMA Driver, (c) 2003-2004,2006 Simtec Electronics
DMA channel 0 at c4808000, irq 33
DMA channel 1 at c4808040, irq 34
DMA channel 2 at c4808080, irq 35
DMA channel 3 at c48080c0, irq 36
S3C244X: Clock Support, DVS off
bio: create slab <bio-0> at 0
SCSI subsystem initialized
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
s3c2440-i2c s3c2440-i2c: slave address 0x10
s3c2440-i2c s3c2440-i2c: bus frequency set to 97 KHz
s3c2440-i2c s3c2440-i2c: i2c-0: S3C I2C adapter
NET: Registered protocol family 2
IP route cache hash table entries: 1024 (order: 0, 4096 bytes)
TCP established hash table entries: 2048 (order: 2, 16384 bytes)
TCP bind hash table entries: 2048 (order: 1, 8192 bytes)
TCP: Hash tables configured (established 2048 bind 2048)
TCP reno registered
NET: Registered protocol family 1
NetWinder Floating Point Emulator V0.97 (extended precision)
JFFS2 version 2.2. (NAND) (SUMMARY)  ?? 2001-2006 Red Hat, Inc.
ROMFS MTD (C) 2007 Red Hat, Inc.
yaffs May 23 2015 19:01:12 Installing. 
msgmni has been set to 119
io scheduler noop registered
io scheduler anticipatory registered (default)
io scheduler deadline registered
io scheduler cfq registered
Console: switching to colour frame buffer device 30x40
fb0: s3c2410fb frame buffer device
lp: driver loaded but no devices found
ppdev: user-space parallel port driver
s3c2440-uart.0: tq2440_serial0 at MMIO 0x50000000 (irq = 70) is a S3C2440
s3c2440-uart.1: tq2440_serial1 at MMIO 0x50004000 (irq = 73) is a S3C2440
s3c2440-uart.2: tq2440_serial2 at MMIO 0x50008000 (irq = 76) is a S3C2440
brd: module loaded
loop: module loaded
Uniform Multi-Platform E-IDE driver
ide-gd driver 1.18
ide-cd driver 5.00
Driver ‘sd‘ needs updating - please use bus_type methods
dm9000 Ethernet Driver, V1.31
S3C24XX NAND Driver, (c) 2004 Simtec Electronics
s3c2440-nand s3c2440-nand: Tacls=2, 20ns Twrph0=3 30ns, Twrph1=2 20ns
NAND device: Manufacturer ID: 0xec, Chip ID: 0xda (Samsung NAND 256MiB 3,3V 8-bit)
Scanning device for bad blocks
Bad eraseblock 1153 at 0x000009020000
Creating 3 MTD partitions on "NAND 256MiB 3,3V 8-bit":
0x000000000000-0x000000040000 : "uboot_1.1.6"
0x000000200000-0x000000500000 : "Linux kernel"
0x000000500000-0x000010000000 : "file system"
usbmon: debugfs is not available
ohci_hcd: USB 1.1 ‘Open‘ Host Controller (OHCI) Driver
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: configuration #1 chosen from 1 choice
hub 1-0:1.0: USB hub found
hub 1-0:1.0: 2 ports detected
usbcore: registered new interface driver libusual
usbcore: registered new interface driver usbserial
USB Serial support registered for generic
usbcore: registered new interface driver usbserial_generic
usbserial: USB Serial Driver core
USB Serial support registered for FTDI USB Serial Device
usbcore: registered new interface driver ftdi_sio
ftdi_sio: v1.4.3:USB FTDI Serial Converters Driver
USB Serial support registered for pl2303
usbcore: registered new interface driver pl2303
pl2303: Prolific PL2303 USB to serial adaptor driver
mice: PS/2 mouse device common for all mice
S3C24XX RTC, (c) 2004,2006 Simtec Electronics
S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics
s3c2410-wdt s3c2410-wdt: watchdog inactive, reset disabled, irq enabled
Advanced Linux Sound Architecture Driver Version 1.0.20.
ALSA device list:
  No soundcards found.
TCP cubic registered
NET: Registered protocol family 17
RPC: Registered udp transport module.
RPC: Registered tcp transport module.
drivers/rtc/hctosys.c: unable to open rtc device (rtc0)
yaffs: dev is 32505858 name is "mtdblock2"
yaffs: passed flags ""
yaffs: Attempting MTD mount on 31.2, "mtdblock2"
yaffs: auto selecting yaffs2
block 1114 is bad
Partially written block 106 detected
Partially written block 106 detected
Partially written block 106 detected
Partially written block 106 detected
Partially written block 106 detected
Partially written block 106 detected
Partially written block 106 detected
Partially written block 106 detected
Partially written block 106 detected
yaffs_read_super: isCheckpointed 0
VFS: Mounted root (yaffs filesystem) on device 31:2.
Freeing init memory: 116K

Please press Enter to activate this console. 
[root@EmbedSky /]# ls
 bin          home         lost+found   proc         [1;34msys          var
 dev          lib          mnt          root         tmp          web
 etc          linuxrc      opt          sbin         usr
[root@EmbedSky /]#