[gBootRoot-user] Re: MTD/JSSF2/grub support?

[Jonathan R. <mma...@ya...>]

"Just starting to look at gbootroot to create a small distro for the
Compaq IA-1's internal 16M flash.  I'd prefer to use MTD/JFFS2 and grub
though.  Any chance of gbootroot supporting that?" 

Sorry Rasmus for not answering this sooner, but for some reason your
message never made it to the list, at least I didn't receive it, though it
did make it to the experimental read-only SF Mail Archive beta. 
Hopefully, this list problem has been fixed by now.

Anyways, yes, I am very interested in supporting MTD devices.  There is
JFFS/JFFS2 filesystem support compiled into the uml kernel which comes
with gbootroot. 

A good way to test this would be to have an arm emulator running on top
of uml with the jffs2 root filessytem running from the mtdblock device
using the blkmtd kernel module. 

Right now uml is a little buggy in respect to blkmtd and jffs/jffs2, in
fact, I hope to send some bug reports to the uml project over the next few
days.  I have gotten it to run by doing this: 

Add this to the kernel config and compile using ARCH=um.
#
# Memory Technology Devices (MTD)
#
CONFIG_MTD=y
CONFIG_MTD_BLKMTD=m
CONFIG_MTD_CHAR=y
CONFIG_MTD_BLOCK=y

How to get a jffs2 fs to properly work under uml assuming a 8192k
ram device (use ramdisk_size=8192), and filesystem sources exist under
loopback:
1.  mount -t hostfs none -o /tmp/gboot_non_root_1000/loopback /mnt1
2.  insmod blkmtd.o device=/dev/rd/2
3.  einfo /dev/mtd/0; erase /dev/mtd/0 0 0x20000
4.  mkfs.jffs2 -r /mnt1/ -o /dev/mtdblock/0 -e 0x20000 -p
5.  mount -t jffs2 /dev/mtdblock/0 /mnt2
6.  umount /dev/mtdblock/0 ( or you won't be able to rmmod blkmtd 

I haven't experimented yet with getting an arm emulator to work, and I
should point out that uml isn't ported yet to arm.  However, the root_fs
created under i386 can provide a model for an arm specific fs. 

I'll be improving the ABS so that it can have user-definable boot methods. 
When this happens a user will be able specify grub rather than lilo, and
lots of other things.  This will be a lot better than the present
situation of just providing one hard-wired boot method.

Regards,


Jonathan