Startup Requirement
You need to build a root filesystem.
This build will create an initial RAM disk as a permanent root filesystem in NAND.
On kernel startup, the bootloader pass the load address of initrd image to the kernel to uncompress and copy the contents of the image into RAM, then frees the memory used and mount it as the initial root file system.
In addition jffs2 and cramfs is can also be used to write to the root filesystem.
System Configuration
For the kernel to support the initial RAM disk, the kernel must be compiled with this.
Change the kernel configuration setting below.
ARCH=arm make menuconfig
Go to 'Device Drivers' --> 'Block devices' --> Select RAM disk support
| <*> RAM block device support (16) Default number of RAM disks (8192) Default RAM disk size (kbytes) |
Go to 'Device Drivers' --> 'Memory Technology Devices (MTD) support' --> Select MTD partitioning support, Command line partition table parsing, Direct char and Cahching block device
| <*> MTD concatenating support [*] MTD partitioning support < > RedBoot partition table parsing [*] Command line partition table parsing < > ARM Firmware Suite partition parsing < > TI AR7 partitioning support *** User Modules And Translation Layers *** <*> Direct char device access to MTD devices -*- Common interface to block layer for MTD 'translation layers <*> Caching block device access to MTD devices |
Go to 'File systems' --> Select Extended fs support
| <*> Second extended fs support [*] Ext2 extended attributes [*] Ext2 POSIX Access Control Lists [*] Ext2 Security Labels [ ] Ext2 execute in place support |
Go to 'File systems' --> 'Miscellaneous filesystems' --> Select Journalling Flash File system and Compressed ROM file system support
| <*> Journalling Flash File System v2 (JFFS2) support (0) JFFS2 debugging verbosity (0 = quiet, 2 = noisy) [*] JFFS2 write-buffering support [ ] Verify JFFS2 write-buffer reads <*> Compressed ROM file system support (cramfs) |
Create initrd Image
First, check the size of the root file system.
du -sh /rootfs
4.0K /rootfs/var
4.0K /rootfs/mnt
4.0K /rootfs/sys
624K /rootfs/bin
4.0K /rootfs/usr/bin
4.0K /rootfs/usr/sbin
12K /rootfs/usr
4.0K /rootfs/proc
3.9M /rootfs/lib
4.0K /rootfs/sbin
4.0K /rootfs/dev
8.0K /rootfs/etc/init.d
36K /rootfs/etc
4.0K /rootfs/tmp
4.6M /rootfs
prepare a temporary storage for the RAM disk.
cd /var/lib/tftpboot
dd if=/dev/zero of=/var/lib/tftpboot/initrd.tmp bs=1k count=8192
Note, the above created a 8 megabytes empty storage which is more than sufficient to save the image.
Create a ext2 filesystem format.
mkfs.ext2 initrd.tmp 8192
mke2fs 1.41.9 (22-Aug-2009)
initrd.tmp is not a block special device.
Proceed anyway? (y,n) y
Filesystem label=
OS type: Linux
Block size=1024 (log=0)
Fragment size=1024 (log=0)
2048 inodes, 8192 blocks
409 blocks (4.99%) reserved for the super user
First data block=1
Maximum filesystem blocks=8388608
1 block group
8192 blocks per group, 8192 fragments per group
2048 inodes per group
Writing inode tables: done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 25 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
Mount the filesystem to a directory.
mkdir /mnt/initrd
mount -o loop initrd.tmp /mnt/initrd
Copy the root filesystem into the directory and change the contents to 'root' ownership.
cp -a /rootfs/* /mnt/initrd
chown -R root.root /mnt/initrd
Dismount the filesystem.
umount /mnt/initrd
Compress the filesystem.
gzip -c -9 initrd.tmp>initrd.gz
ls -l initrd.*
-rw-r--r-- 1 root root 2164377 2010-03-05 16:06 initrd.gz
-rw-r--r-- 1 root root 8388608 2010-03-05 15:47 initrd.tmp
Note, the final RAM disk is only one quarter of the original file size.
Refresh the initrd Image
Power on the board into the bootloader command prompt.
Verify the table information, we need the size and offset of the root partition.
MINI2440 # mtdparts
device nand0, # parts = 4
#: name size offset mask_flags
0: u-boot 0x00040000 0x00000000 0
1: env 0x00020000 0x00040000 0
2: kernel 0x00500000 0x00060000 0
3: root 0x07aa0000 0x00560000 0
active partition: nand0,0 - (u-boot) 0x00040000 @ 0x00000000
defaults:
mtdids : nand0=mini2440-nand
mtdparts:
The output shows that root is at the last block and start at 0x00560000 offset address with size of 7aa0000 (about 122 megabytes).
Clean up the root partition.
MINI2440 # nand erase 560000 7aa0000
NAND erase: device 0 offset 0x560000, size 0x7aa0000
Skipping bad block at 0x06b40000
Skipping bad block at 0x07f80000
Skipping bad block at 0x07fa0000
Skipping bad block at 0x07fc0000
Skipping bad block at 0x07fe0000
OK
Download image into the specify location, make sure you have start up the tftp server.
MINI2440 # tftp 32000000 initrd.gz
dm9000 i/o: 0x20000300, id: 0x90000a46
DM9000: running in 16 bit mode
MAC: 08:00:2f:00:00:02
TFTP from server 192.168.114.181; our IP address is 192.168.114.190
Filename 'initrd.gz'.
Load address: 0x32000000
Loading: T T T #################################################################
#################################################################
##################
done
Bytes transferred = 2164377 (210699 hex)
Write image to the root partition, if there is a write problem you may have to refresh the NAND from scratch.
MINI2440 # nand write.e 32000000 560000 ${filesize}
NAND write: device 0 offset 0x560000, size 0x210699
Writing data at 0x770000 -- 100% complete.
2164377 bytes written: OK
Save the file size, it is use later to setup the boot argument.
MINI2440 # setenv initrd_size $(filesize)
MINI2440 # saveenv
Saving Environment to NAND...
Erasing Nand...Writing to Nand... done
Finally, Set the boot argument to load from the initrd and save all the settings.
MINI2440 # setenv 'bootcmd nand read 32000000 60000 200000;nand read 30800000 560000 ${initrd_size};bootm'
MINI2440 # setenv bootargs initrd=0x30800000,0x${initrd_size} init=/linuxrc root=/dev/ram0 rw console=ttySAC0 mini2440=0tb
MINI2440 # saveenv
Reboot the device to run the new update version.
MINI2440 # reset
U-Boot 1.3.2-mini2440 (Feb 26 2010 - 17:34:45)
I2C: ready
DRAM: 64 MB
Flash: 2 MB
NAND: Bad block table not found for chip 0
Bad block table not found for chip 0
128 MiB
Found Environment offset in OOB..
USB: S3C2410 USB Deviced
In: serial
Out: serial
Err: serial
MAC: 08:00:2f:00:00:02
Hit any key to stop autoboot: 0
NAND read: device 0 offset 0x60000, size 0x200000
2097152 bytes read: OK
NAND read: device 0 offset 0x560000, size 0x2106d4
2164436 bytes read: OK
## Booting kernel from Legacy Image at 32000000 ...
Image Name:
Created: 2010-03-02 14:51:28 UTC
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 2053096 Bytes = 2 MB
Load Address: 30008000
Entry Point: 30008000
Verifying Checksum ... OK
Loading Kernel Image ... OK
OK
Starting kernel ...
Uncompressing Linux.............................................................
Linux version 2.6.32.7 (root@gmax.localdomain) (gcc version 4.4.1 (Sourcery G++0
CPU: ARM920T [41129200] revision 0 (ARMv4T), cr=c0007177
CPU: VIVT data cache, VIVT instruction cache
Machine: MINI2440
Memory policy: ECC disabled, Data cache writeback
CPU S3C2440A (id 0x32440001)
S3C24XX Clocks, (c) 2004 Simtec Electronics
S3C244X: core 405.000 MHz, memory 101.250 MHz, peripheral 50.625 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: initrd=0x30800000,0x2106D4 init=/linuxrc root=/dev/ram0 rwb
PID hash table entries: 256 (order: -2, 1024 bytes)
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: 58468KB available (3620K code, 420K data, 128K init, 0K highmem)
SLUB: Genslabs=11, HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
Hierarchical RCU implementation.
NR_IRQS:85
irq: clearing subpending status 00000002
Console: colour dummy device 80x30
console [ttySAC0] enabled
Calibrating delay loop... 201.93 BogoMIPS (lpj=504832)
Mount-cache hash table entries: 512
CPU: Testing write buffer coherency: ok
NET: Registered protocol family 16
MINI2440: Option string mini2440=0tb
MINI2440: LCD [0:240x320] 1:800x480 2:1024x768 3:240x320 4:640x480
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
S3C24XX CPU Frequency driver, s3c244x cpu support
bio: create slabat 0
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
s3c-i2c s3c2440-i2c: slave address 0x10
s3c-i2c s3c2440-i2c: bus frequency set to 98 KHz
s3c-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
RPC: Registered udp transport module.
RPC: Registered tcp transport module.
RPC: Registered tcp NFSv4.1 backchannel transport module.
Trying to unpack rootfs image as initramfs...
rootfs image is not initramfs (no cpio magic); looks like an initrd
Freeing initrd memory: 2112K
squashfs: version 4.0 (2009/01/31) Phillip Lougher
JFFS2 version 2.2. (NAND) �© 2001-2006 Red Hat, Inc.
msgmni has been set to 118
alg: No test for stdrng (krng)
io scheduler noop registered
io scheduler anticipatory registered (default)
io scheduler deadline registered
io scheduler cfq registered
Console: switching to colour frame buffer device 60x53
fb0: s3c2410fb frame buffer device
s3c2440-uart.0: ttySAC0 at MMIO 0x50000000 (irq = 70) is a S3C2440
s3c2440-uart.1: ttySAC1 at MMIO 0x50004000 (irq = 73) is a S3C2440
s3c2440-uart.2: ttySAC2 at MMIO 0x50008000 (irq = 76) is a S3C2440
brd: module loaded
at24 0-0050: 1024 byte 24c08 EEPROM (writable)
S3C24XX NAND Driver, (c) 2004 Simtec Electronics
s3c24xx-nand s3c2440-nand: Tacls=1, 9ns Twrph0=3 29ns, Twrph1=2 19ns
s3c24xx-nand s3c2440-nand: NAND soft ECC
NAND device: Manufacturer ID: 0xec, Chip ID: 0xf1 (Samsung NAND 128MiB 3,3V 8-b)
Creating 4 MTD partitions on "NAND 128MiB 3,3V 8-bit":
0x000000000000-0x000000040000 : "u-boot"
0x000000040000-0x000000060000 : "u-boot-env"
0x000000060000-0x000000560000 : "kernel"
0x000000560000-0x000008000000 : "root"
dm9000 Ethernet Driver, V1.31
eth0: dm9000e at c486e300,c4872304 IRQ 51 MAC: 08:00:2f:00:00:02 (chip)
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
mice: PS/2 mouse device common for all mice
input: gpio-keys as /devices/platform/gpio-keys/input/input0
s3c2440-ts s3c2440-ts: Starting
Created group ts filter len 12 depth 2 close 10 thresh 6
Created Median ts filter len 20 depth 2 dec 24
Created Mean ts filter len 4 depth 2 thresh 65535
Created Linear ts filter depth 2
s3c2440-ts s3c2440-ts: 4 filter(s) initialized
s3c2440-ts s3c2440-ts: successfully loaded
input: s3c2410 TouchScreen as /devices/virtual/input/input1
S3C24XX RTC, (c) 2004,2006 Simtec Electronics
s3c2410-rtc s3c2410-rtc: rtc disabled, re-enabling
s3c2410-rtc s3c2410-rtc: rtc core: registered s3c as rtc0
i2c /dev entries driver
S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics
s3c2410-wdt s3c2410-wdt: watchdog inactive, reset disabled, irq enabled
cpuidle: using governor ladder
sdhci: Secure Digital Host Controller Interface driver
sdhci: Copyright(c) Pierre Ossman
s3c-sdi s3c2440-sdi: powered down.
s3c-sdi s3c2440-sdi: mmc0 - using pio, sw SDIO IRQ
Registered led device: led1
Registered led device: led2
Registered led device: led3
Registered led device: led4
Registered led device: backlight
usbcore: registered new interface driver hiddev
usbcore: registered new interface driver usbhid
usbhid: v2.6:USB HID core driver
Advanced Linux Sound Architecture Driver Version 1.0.21.
No device for DAI UDA134X
No device for DAI s3c24xx-i2s
S3C24XX_UDA134X SoC Audio driver
UDA134X SoC Audio Codec
asoc: UDA134X <-> s3c24xx-i2s mapping ok
ALSA device list:
#0: S3C24XX_UDA134X (UDA134X)
TCP cubic registered
NET: Registered protocol family 17
s3c2410-rtc s3c2410-rtc: setting system clock to 2008-12-29 06:17:58 UTC (12305)
RAMDISK: gzip image found at block 0
VFS: Mounted root (ext2 filesystem) on device 1:0.
Freeing init memory: 128K
Please press Enter to activate this console.
[root@(none) /]#
Create JFFS2 and CRAMFS Image
Alternately, JFFS2 can be used to create a root filesystem.
mkfs.jffs2 -r /rootfs -o rootfs.jffs2 -e 0x20000 -n
Or in CRAMFS format.
mkcramfs /rootfs rootfs.cramfs
Reboot the device into bootloader command prompt.
Download image into the specify location.
MINI2440 # tftp 32000000 rootfs.jffs2
Clean up the root partition.
MINI2440 # nand erase root
Write image to the root partition.
MINI2440 # nand write.e 32000000 root ${filesize}
Set the boot argument to load from the initrd and save all the settings.
MINI2440 # setenv bootcmd 'nboot.e kernel;bootm'
MINI2440 # setenv bootargs noinitrd init=/linuxrc root=/dev/mtdblock3 rootfstype=jffs2 console=ttySAC0 mini2440=0tb
MINI2440 # saveenv
Reboot the device to run the new update version.
MINI2440 # reset
U-Boot 1.3.2-mini2440 (Feb 26 2010 - 17:34:45)
I2C: ready
DRAM: 64 MB
Flash: 2 MB
NAND: Bad block table not found for chip 0
Bad block table not found for chip 0
128 MiB
Found Environment offset in OOB..
USB: S3C2410 USB Deviced
In: serial
Out: serial
Err: serial
MAC: 08:00:2f:00:00:02
Hit any key to stop autoboot: 0
Loading from NAND 128MiB 3,3V 8-bit, offset 0x60000
Image Name:
Created: 2010-03-02 14:51:28 UTC
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 2053096 Bytes = 2 MB
Load Address: 30008000
Entry Point: 30008000
## Booting kernel from Legacy Image at 32000000 ...
Image Name:
Created: 2010-03-02 14:51:28 UTC
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 2053096 Bytes = 2 MB
Load Address: 30008000
Entry Point: 30008000
Verifying Checksum ... OK
Loading Kernel Image ... OK
OK
Starting kernel ...
Uncompressing Linux.............................................................
Linux version 2.6.32.7 (root@gmax.localdomain) (gcc version 4.4.1 (Sourcery G++0
CPU: ARM920T [41129200] revision 0 (ARMv4T), cr=c0007177
CPU: VIVT data cache, VIVT instruction cache
Machine: MINI2440
Memory policy: ECC disabled, Data cache writeback
CPU S3C2440A (id 0x32440001)
S3C24XX Clocks, (c) 2004 Simtec Electronics
S3C244X: core 405.000 MHz, memory 101.250 MHz, peripheral 50.625 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 init=/linuxrc root=/dev/mtdblock3 console=ttySAC02
PID hash table entries: 256 (order: -2, 1024 bytes)
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: 60584KB available (3620K code, 420K data, 128K init, 0K highmem)
SLUB: Genslabs=11, HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
Hierarchical RCU implementation.
NR_IRQS:85
irq: clearing subpending status 00000002
Console: colour dummy device 80x30
console [ttySAC0] enabled
Calibrating delay loop... 201.93 BogoMIPS (lpj=504832)
Mount-cache hash table entries: 512
CPU: Testing write buffer coherency: ok
NET: Registered protocol family 16
MINI2440: Option string mini2440=0tb
MINI2440: LCD [0:240x320] 1:800x480 2:1024x768 3:240x320 4:640x480
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
S3C24XX CPU Frequency driver, s3c244x cpu support
bio: create slabat 0
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
s3c-i2c s3c2440-i2c: slave address 0x10
s3c-i2c s3c2440-i2c: bus frequency set to 98 KHz
s3c-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
RPC: Registered udp transport module.
RPC: Registered tcp transport module.
RPC: Registered tcp NFSv4.1 backchannel transport module.
squashfs: version 4.0 (2009/01/31) Phillip Lougher
JFFS2 version 2.2. (NAND) © 2001-2006 Red Hat, Inc.
msgmni has been set to 118
alg: No test for stdrng (krng)
io scheduler noop registered
io scheduler anticipatory registered (default)
io scheduler deadline registered
io scheduler cfq registered
Console: switching to colour frame buffer device 60x53
fb0: s3c2410fb frame buffer device
s3c2440-uart.0: ttySAC0 at MMIO 0x50000000 (irq = 70) is a S3C2440
s3c2440-uart.1: ttySAC1 at MMIO 0x50004000 (irq = 73) is a S3C2440
s3c2440-uart.2: ttySAC2 at MMIO 0x50008000 (irq = 76) is a S3C2440
brd: module loaded
at24 0-0050: 1024 byte 24c08 EEPROM (writable)
S3C24XX NAND Driver, (c) 2004 Simtec Electronics
s3c24xx-nand s3c2440-nand: Tacls=1, 9ns Twrph0=3 29ns, Twrph1=2 19ns
s3c24xx-nand s3c2440-nand: NAND soft ECC
NAND device: Manufacturer ID: 0xec, Chip ID: 0xf1 (Samsung NAND 128MiB 3,3V 8-b)
Creating 4 MTD partitions on "NAND 128MiB 3,3V 8-bit":
0x000000000000-0x000000040000 : "u-boot"
0x000000040000-0x000000060000 : "u-boot-env"
0x000000060000-0x000000560000 : "kernel"
0x000000560000-0x000008000000 : "root"
dm9000 Ethernet Driver, V1.31
eth0: dm9000e at c486e300,c4872304 IRQ 51 MAC: 08:00:2f:00:00:02 (chip)
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
mice: PS/2 mouse device common for all mice
input: gpio-keys as /devices/platform/gpio-keys/input/input0
s3c2440-ts s3c2440-ts: Starting
Created group ts filter len 12 depth 2 close 10 thresh 6
Created Median ts filter len 20 depth 2 dec 24
Created Mean ts filter len 4 depth 2 thresh 65535
Created Linear ts filter depth 2
s3c2440-ts s3c2440-ts: 4 filter(s) initialized
s3c2440-ts s3c2440-ts: successfully loaded
input: s3c2410 TouchScreen as /devices/virtual/input/input1
S3C24XX RTC, (c) 2004,2006 Simtec Electronics
s3c2410-rtc s3c2410-rtc: rtc disabled, re-enabling
s3c2410-rtc s3c2410-rtc: rtc core: registered s3c as rtc0
i2c /dev entries driver
S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics
s3c2410-wdt s3c2410-wdt: watchdog inactive, reset disabled, irq enabled
cpuidle: using governor ladder
sdhci: Secure Digital Host Controller Interface driver
sdhci: Copyright(c) Pierre Ossman
s3c-sdi s3c2440-sdi: powered down.
s3c-sdi s3c2440-sdi: mmc0 - using pio, sw SDIO IRQ
Registered led device: led1
Registered led device: led2
Registered led device: led3
Registered led device: led4
Registered led device: backlight
usbcore: registered new interface driver hiddev
usbcore: registered new interface driver usbhid
usbhid: v2.6:USB HID core driver
Advanced Linux Sound Architecture Driver Version 1.0.21.
No device for DAI UDA134X
No device for DAI s3c24xx-i2s
S3C24XX_UDA134X SoC Audio driver
UDA134X SoC Audio Codec
asoc: UDA134X <-> s3c24xx-i2s mapping ok
ALSA device list:
#0: S3C24XX_UDA134X (UDA134X)
TCP cubic registered
NET: Registered protocol family 17
s3c2410-rtc s3c2410-rtc: setting system clock to 2008-12-29 07:08:31 UTC (12305)
VFS: Mounted root (jffs2 filesystem) on device 31:3.
Freeing init memory: 128K
Please press Enter to activate this console.
[root@(none) /]#
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