Kernelupdate in runtime

RSchubert · Aug 31st 2012

Is there a possibility to update the Kernel (writing a new zImage into the NAND) from a program running on picomod ?

Thanks and kind regards
RSchubert

fs-support_DK · Sep 3rd 2012

Yes, that is possible.
You need set modify the bootargs/mtdparts like that (see the access rights for Kernel) - this line is from PicoMOD7A, pls set appropriate for your PicoMOD7:

Code

mtdparts=fsnand1:256k(NBoot)ro;fsnand0:512k@256k(UBoot)ro,256k(UBootEnv)ro,4m(UserDef),3m(Kernel),-(TargetFS)

In Buildroot you need to add tools to busybox with:

Code

make busybox-menuconfig

and add:

Code

CONFIG_NANDWRITE and CONFIG_FLASH_ERASEALL

Then with the new rootfs and the corresponding bootargs you can update Linux Kernel Image from the serial command line (Linux) like:

Code

# cd /home
# ifconfig eth0 10.0.0.27 netmask 255.255.255.0 up
# mount -o remount,rw /
# tftp -g -r zImagePV210 10.0.0.74
zImagePV210 100% |*******************************| 3000k 0:00:00 ETA
#
# flash_eraseall -j /dev/mtd3
Erasing 128 Kibyte @ 300000 - 100% complete.Cleanmarker written at 2e0000.
# nandwrite -p /dev/mtd3 zImagePV210
Writing at 0x00000000
Writing at 0x00020000
Writing at 0x00040000
Writing at 0x00060000
Writing at 0x00080000
Writing at 0x000a0000
Writing at 0x000c0000
Writing at 0x000e0000
Writing at 0x00100000
Writing at 0x00120000
Writing at 0x00140000
Writing at 0x00160000
Writing at 0x00180000
Writing at 0x001a0000
Writing at 0x001c0000
Writing at 0x001e0000
Writing at 0x00200000
Writing at 0x00220000
Writing at 0x00240000
Writing at 0x00260000
Writing at 0x00280000
Writing at 0x002a0000
Writing at 0x002c0000
Writing at 0x002e0000

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RSchubert · Sep 3rd 2012

Thanks,

I will try and tell the results.

RSchubert · Sep 3rd 2012

I have the flash_eraseall and nandwrite commands running. On /dev/mtd3 I have no write access (I removed the "ro" flag behind the Kernel definition).

When looking to the mtdparts again I see NBoot 128k,UBoot 512k,UBootEnv 128k,UserDef 512k,Kernel 4M,TargetFS.

Is it correct that the Kernel must be /dev/mtd4 instead of /dev/mtd3? If yes how do I create the mtd4 and mtdblock4 devices?

Kind regards...

fs-support_DK · Sep 3rd 2012

Take a look at the debug output (again this is PicoMOD7A):

Creating 5 MTD partitions on "fsnand0":
0x000000040000-0x0000000c0000 : "UBoot"
0x0000000c0000-0x000000100000 : "UBootEnv"
0x000000100000-0x000000500000 : "UserDef"
0x000000500000-0x000000800000 : "Kernel"
0x000000800000-0x000008000000 : "TargetFS"

You see 0=UBoot .. 3=Kernel

# cat /sys/class/mtd/mtd3/name
Kernel

Pls search for 'Kernel' and use the corresponding mtd*

RSchubert · Sep 3rd 2012

On my device there are 6 partitions. I have an additional NBoot partition 0. So the Kernel is /dev/mtd4 but there's no mtd4 device in the /dev directory. I have created a device:

Code

mknod /dev/mtd4 c 90 8
mknod mtdblock4 b 31 4

Now I can read the Kernel:

Code

cp /dev/mtd4 /root/Kernel.dat

but writing is not possible (even after chmod 664 /dev/mtd4)

Code

flash_eraseall: can't open '/dev/mtd4': Permission denied

In my UBootEnv the mtdparts and bootargs are without the 'ro' flag after the Kernel definition.

fs-support_DK · Sep 4th 2012

Code

# cat /sys/class/mtd/mtd4/name
Kernel
# ls -lah /dev/mtd4
crw-rw---- 1 root root 90, 8 Jan 1 00:00 /dev/mtd4
# flash_eraseall -j /dev/mtd4
Erasing 128 Kibyte @ 400000 - 100% complete.Cleanmarker written at 3e0000.

Please make sure your bootargs look like (and run 'saveenv' to save modifications):

Code

Kernel command line: console=ttySAC2,38400 mtdparts=qba8nand0:128k(NBoot)ro,512k(UBoot)ro,128k(UBootEnv)ro,512k(UserDef),4m(Kernel),-(TargetFS) init=linuxrc root=/dev/nfs rw nfsroot=/rootfs ip=10.0.0.27:10.0.0.74:10.0.0.5:255.255.255.0

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