yaffs这种文件系统专门为NAND Flash设计的嵌入式文件系统，

虽减少了一些功能，但比JFFS速度更快，占用内存更少。

一般而言，在Nor Flash上使用JFFS2文件系统，在NAND Flash上使用YAFFS文件系统。

我在JFFS2与YAFFS的性能比较表格上看到，YAFFS适用的操作系统很多，容易移植。

(1) 将yaffs2代码加入内核

通过yaffs目录下的脚本文件patch-ker.sh 来给内核打补丁，操作如下：

 cd  /work/system/Development/yaffs2

 ./patch-ker.sh  c  /work/linux-2.6.22.6

(2) 配置、编译内核

make s3c2410_defconfig

make menuconfig

File systems --->

      Miscellaneous filesystems --->

               YAFFS2 file  system support

(3)u-boot 烧写内核

OpenJTAG> tftp 0x32000000 uImage
dm9000 i/o: 0x28000300, id: 0x90000a46
DM9000: running in 16 bit mode
MAC: 08:00:3e:26:0a:5b
TFTP from server 172.22.136.38; our IP address is 172.22.136.55
Filename 'uImage'.
Load address: 0x32000000
Loading: checksum bad
checksum bad
T #################################################################
     #################################################################
     #################################################################
     #################################################################
     ###########################################
done
Bytes transferred = 1549248 (17a3c0 hex)

OpenJTAG  > nand erase 0 0x00200000
NAND erase: device 0 offset 0x0, size 0x200000
Erasing at 0x1fc000 -- 100% complete.
OK
OpenJTAG> nand write.jffs2 0x32000000 0 $(filesize)

NAND write: device 0 offset 0x0, size 0x17a3bc

Writing data at 0x17a200 -- 100% complete.
1549244 bytes written: OK
OpenJTAG> nboot 0x32000000 0 0

Loading from NAND 64MiB 3,3V 8-bit, offset 0x0
   Image Name:   Linux-2.6.22.6
   Created:      2009-12-09  13:38:02 UTC
   Image Type:   ARM Linux Kernel Image (uncompressed)
   Data Size:    1549180 Bytes =  1.5 MB
   Load Address: 30008000
   Entry Point:  30008000
OpenJTAG> bootm 0x32000000
## Booting image at 32000000 ...
   Image Name:   Linux-2.6.22.6
   Created:      2009-12-09  13:38:02 UTC
   Image Type:   ARM Linux Kernel Image (uncompressed)
   Data Size:    1549180 Bytes =  1.5 MB
   Load Address: 30008000
   Entry Point:  30008000
   Verifying Checksum ... OK

OK

Starting kernel ...

Uncompressing Linux..................................................................................................... done, booting the kernel.
Linux version 2.6.22.6 (root@huanghuang-desktop) (gcc version 3.4.5) #1 Wed Dec 9 21:37:57 CST 2009
CPU: ARM920T [41129200] revision 0 (ARMv4T), cr=c0007177
Machine: SMDK2410
Memory policy: ECC disabled, Data cache writeback
CPU S3C2410A (id 0x32410002)
S3C2410: core 200.000 MHz, memory 100.000 MHz, peripheral 50.000 MHz
S3C24XX 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.  Total pages: 16256
Kernel command line: noinitrd root=/dev/mtdblock3 init=/linuxrc console=ttySAC0
irq: clearing subpending status 00000002
PID hash table entries: 256 (order: 8, 1024 bytes)
timer tcon=00500000, tcnt a2c1, tcfg 00000200,00000000, usec 00001eb8
Console: colour dummy device 80x30
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: 61568KB available (2864K code, 314K data, 132K init)
Mount-cache hash table entries: 512
CPU: Testing write buffer coherency: ok
NET: Registered protocol family 16
S3C2410 Power Management, (c) 2004 Simtec Electronics
S3C2410: Initialising architecture
S3C24XX DMA Driver, (c) 2003-2004,2006 Simtec Electronics
DMA channel 0 at c4800000, irq 33
DMA channel 1 at c4800040, irq 34
DMA channel 2 at c4800080, irq 35
DMA channel 3 at c48000c0, irq 36
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
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
NetWinder Floating Point Emulator V0.97 (double precision)
JFFS2 version 2.2. (NAND) © 2001-2006 Red Hat, Inc.
yaffs Dec  9 2009 21:36:30 Installing.
io scheduler noop registered
io scheduler anticipatory registered (default)
io scheduler deadline registered
io scheduler cfq registered
s3c2410-lcd s3c2410-lcd: no platform data for lcd, cannot attach
s3c2410-lcd: probe of s3c2410-lcd failed with error -22
lp: driver loaded but no devices found
ppdev: user-space parallel port driver
S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics
Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, IRQ sharing enabled
s3c2410-uart.0: s3c2410_serial0 at MMIO 0x50000000 (irq = 70) is a S3C2410
s3c2410-uart.1: s3c2410_serial1 at MMIO 0x50004000 (irq = 73) is a S3C2410
s3c2410-uart.2: s3c2410_serial2 at MMIO 0x50008000 (irq = 76) is a S3C2410
RAMDISK driver initialized: 16 RAM disks of 4096K size 1024 blocksize
loop: module loaded
dm9000 Ethernet Driver
Uniform Multi-Platform E-IDE driver Revision: 7.00alpha2
ide: Assuming 50MHz system bus speed for PIO modes; override with idebus=xx
BAST NOR-Flash Driver, (c) 2004 Simtec Electronics
S3C24XX NAND Driver, (c) 2004 Simtec Electronics
s3c2410-nand s3c2410-nand: Tacls=3, 30ns Twrph0=7 70ns, Twrph1=3 30ns
NAND device: Manufacturer ID: 0xec, Chip ID: 0x76 (Samsung NAND 64MiB 3,3V 8-bit)
Scanning device for bad blocks
Creating 3 MTD partitions on "NAND 64MiB 3,3V 8-bit":
0x00000000-0x00200000 : "kernel"
0x00200000-0x00a00000 : "jffs2"
0x00a00000-0x04000000 : "yaffs"
usbmon: debugfs is not available
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
mice: PS/2 mouse device common for all mice
S3C24XX RTC, (c) 2004,2006 Simtec Electronics
s3c2410-i2c s3c2410-i2c: slave address 0x10
s3c2410-i2c s3c2410-i2c: bus frequency set to 390 KHz
s3c2410-i2c s3c2410-i2c: i2c-0: S3C I2C adapter
TCP cubic registered
NET: Registered protocol family 1
drivers/rtc/hctosys.c: unable to open rtc device (rtc0)
Root-NFS: No NFS server available, giving up.
VFS: Unable to mount root fs via NFS, trying floppy.
VFS: Cannot open root device "mtdblock3" or unknown-block(2,0)
Please append a correct "root=" boot option; here are the available partitions:
1f00       2048 mtdblock0 (driver?)
1f01       8192 mtdblock1 (driver?)
1f02      55296 mtdblock2 (driver?)
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(2,0)

(4) 上面还有那行错误，我试了网上的几种方法，

将linux_cmd_line设置为"noinitrd root=/dev/mtdblock/3 init=/linuxrc console=ttySAC0,115200"，问题

依旧。根据东山老师所说，这还是属于正常现象，待后面构建linux根文件系统之后再说。。