NFS boot of a beagleboard-xm (CONFIG_USB_NET_SMSC95XX=m)

[gdamjan]

The BeagleBoard-xM uses the generic linux-armv7 kernel, which unfortunately, doesn't have the smsc95xx ethernet driver built-in but as a module. This precludes me from having the root mounted from NFS, and I need to do this since my sd cards are failing.

My questions are:
* would it be unrealistic to add CONFIG_USB_NET_SMSC95XX=y in the armv7 kernel?
* any ideas how to make an initramfs from my x86 host?
* other ideas?

[moonman]

initramfs is easy to make. Just install mkinitcpio and run mkinitcpio -g /boot/initramfs-linux.img on the device.
You have to do it every kernel update. Also check your uboot configuration to see what name it expects for the initramfs image, if at all.

[gdamjan]

u-boot does try to load an initramfs (initramfs-linux.img - also evidenced by the alarm patch to u-boot).

I know that initramfs is just a cpio archive, it's still not trivial to create with all the binaries, libraries and scripts.

In the end, this was my approach:

• Installed qemu-user-static from aur on the x86 nfs server
• setup /etc/binfmt.d/qemu-arm.conf
• systemctl restart systemd-binfmt
• cp /usr/bin/qemu-arm-static $ARMROOT/usr/bin/qemu-arm
• systemd-nspawn -D $ARMROOT

from this point I could run pacman and mkinitcpio (btw, ARMROOT is /home/nfs/bbxm here)

I also had to follow the instructions in the wiki to hack on the initcpio for NFS4.

my /boot/uEnv.txt is:
$this->bbcode_second_pass_code('', 'optargs=smsc95xx.macaddr=9b:01:cc:7e:5c:23 nfsroot=192.168.117.2:/home/nfs/bbxm,vers=4.2 ip=:::::eth0:dhcp
dvimode=800x600MR-16@60
root=/dev/nfs')

[gdamjan]

Actually a better way than copying the qemu-arm binary is to bind it wit nspan:
$this->bbcode_second_pass_code('', '
sudo systemd-nspawn -D $ARMROOT \
--bind-ro=/usr/bin/qemu-arm-static:/usr/bin/qemu-arm \
--bind-ro=/etc/resolv.conf:/run/systemd/resolve/resolv.conf
')