[U-Boot] Hang while booting kernel via tftp/nfs on cubieboard2

[Ajay Garg <ajaygargnsit@gmail.com>]

Hi All.


a)
As a pre-requisite, on the host-machine (serverip 192.168.0.1), the
nfs-export is listed fine :

ajay at latitude-3480:~showmount -e localhost
Export list for localhost:
/srv/nfs/cubieboard2 *


b)
The zImage and dtb files have been generated from 4.6 kernel, as per steps at
https://github.com/maronai/cubieboard/wiki/3.1.-Compiling-mainline-kernel-for-CubieBoard2-and-CubieTruck


Now, when trying to boot cubieboard2 via tftp/nfs, I get a hang, all
details as below :

###########################################################################################################
U-Boot SPL 2017.01-2 (Jan 18 2017 - 21:30:38)
DRAM: 1024 MiB
CPU: 912000000Hz, AXI/AHB/APB: 3/2/2
Trying to boot from MMC1

U-Boot 2017.01-2 (Jan 18 2017 - 21:30:38 -0700) Arch Linux ARM

CPU:   Allwinner A20 (SUN7I)
Model: Cubietech Cubieboard2
I2C:   ready
DRAM:  1 GiB
MMC:   SUNXI SD/MMC: 0
In:    serial
Out:   serial
Err:   serial
SCSI:  SATA link 0 timeout.
AHCI 0001.0100 32 slots 1 ports 3 Gbps 0x1 impl SATA mode
flags: ncq stag pm led clo only pmp pio slum part ccc apst
Net:   eth0: ethernet at 01c50000
Hit any key to stop autoboot:  0

=> printenv
autoboot=run loadkernel && run setargs && true && bootm 0x48000000
baudrate=115200
boot_ram=saved_stdout=$stdout;setenv stdout nc;if iminfo 0x41000000;
then true; setenv stdout $saved_stdout; source 0x41000000;else setenv
stdi
bootcmd=if run loadbootenv; then echo Loaded environment from
${bootenv};env import -t ${scriptaddr} ${filesize};fi;if test -n
"${uenvcmd}"; t;
bootdelay=3
bootenv=uEnv.txt
bootscr=boot.scr
console=ttyS0,115200
device=mmc
ethact=ethernet at 01c50000
ethaddr=12:34:56:78:90:ab
fdtcontroladdr=7af2e820
ipaddr=192.168.0.2
kernel=uImage
loadbootenv=fatload $device $partition $scriptaddr ${bootenv} ||
ext2load $device $partition $scriptaddr boot/${bootenv} || ext2load
$device $}
loadbootscr=fatload $device $partition $scriptaddr ${bootscr} ||
ext2load $device $partition $scriptaddr boot/${bootscr} ||ext2load
$device $p}
loadkernel=if bootpath=/boot/ && ext2load $device $partition
0x43000000 ${bootpath}script.bin && ext2load $device $partition
0x48000000 ${booti
loglevel=8
panicarg=panic=10
partition=0:1
scriptaddr=0x44000000
serial#=1651660f06c3457c
serverip=192.168.0.1
setargs=if test -z \\"$root\\"; then if test \\"$bootpath\\" =
"/boot/"; then root="/dev/mmcblk0p1 rootwait"; else
root="/dev/mmcblk0p2 rootwa}
stderr=serial
stdin=serial
stdout=serial

Environment size: 1979/131068 bytes

=> tftp 0x49000000 sun7i-a20-cubieboard2.dtb
Speed: 100, full duplex
Using ethernet at 01c50000 device
TFTP from server 192.168.0.1; our IP address is 192.168.0.2
Filename 'sun7i-a20-cubieboard2.dtb'.
Load address: 0x49000000
Loading: ###
         4 MiB/s
done
Bytes transferred = 29537 (7361 hex)

=> tftp 0x46000000 zImage-Cubieboard2
Speed: 100, full duplex
Using ethernet at 01c50000 device
TFTP from server 192.168.0.1; our IP address is 192.168.0.2
Filename 'zImage-Cubieboard2'.
Load address: 0x46000000
Loading: #################################################################
         #################################################################
         #################################################################
         ####################################
         4.6 MiB/s
done
Bytes transferred = 3388416 (33b400 hex)

=> bootz 0x46000000 - 0x49000000 console=ttyS0,115200 root=/dev/nfs
nfsroot=192.168.0.1:/srv/nfs/cubieboard2,nfsvers=3
ip=192.168.0.2:192.168.0.1::255.255.255.0:cubieboard2 ignore_loglevel
cma=128M
## Flattened Device Tree blob at 49000000
   Booting using the fdt blob at 0x49000000
   Loading Device Tree to 7af23000, end 7af2d360 ... OK

Starting kernel ...
###########################################################################################################


What am I doing wrong? In general, how do I proceed to debug to get
this working?

Will be grateful for pointers.


Thanks and Regards,
Ajay