rootfile system porting for FPGA [/bin/sh: can't access tty; job control turned off]

pcuser p pcuser.mails at gmail.com
Mon May 7 08:51:05 EDT 2012


Hi,
I am newbie to linux kernel,doing kernel porting on a arm926ej-s FPGA board
(only timer & uart hardware is available in the board)

I'm using busybox for rootfs(busy box binary is built with "static" option
enabled)

After file system is mounted,I can see the below message,
"VFS: Mounted root (cramfs filesystem) readonly on device 1:0."
"Freeing init memory: 80K"

I am expecting to get to shell prompt and give some commands (ls,clear)
after file system gets mounted.

*I am ending up in the shell prompt with the message as below:*
"entered linuxrc script"
"/bin/sh: can't access tty; job control turned off
/ $"

I am getting no response from terminal for any commands entered in the shel
lafter this.

I went through this FAQ in http://www.busybox.net/FAQ.html#job_control
I could not follow this exactly.

my kernel commad line is
"mem=32M console=ttySAC0,115200 root=/dev/ram0 init=/linuxrc
initrd=0x80800000,8M user_debug=31"


*I could see 2 issues here:*
1. I am using shell on /dev/console which is not correct  as mentioned in
busybox FAQ
2. linuxrc and /etc/inittab files may not be correct.

I  think the problem could be in both above 2 cases.


Below are my /linuxrc and /etc/inittab file contents
*linuxrc:

*#!/bin/sh
/bin/echo "entered linuxrc script"
/bin/sh
exec /sbin/init

*
/etc/inittab:*

id:3:initdefault:
# System initialization.
si::sysinit:/etc/rc.d/rc.
sysinit
l0:0:wait:/etc/rc.d/rc 0
l1:1:wait:/etc/rc.d/rc 1
l2:2:wait:/etc/rc.d/rc 2
l3:3:wait:/etc/rc.d/rc 3
l4:4:wait:/etc/rc.d/rc 4
l5:5:wait:/etc/rc.d/rc 5
l6:6:wait:/etc/rc.d/rc 6

# Trap CTRL-ALT-DELETE
ca::ctrlaltdel:/sbin/shutdown -t3 -r now

# When our UPS tells us power has failed, assume we have a few minutes
# of power left.  Schedule a shutdown for 2 minutes from now.
# This does, of course, assume you have powerd installed and your
# UPS connected and working correctly.
pf::powerfail:/sbin/shutdown -f -h +2 "Power Failure; System Shutting Down"

# If power was restored before the shutdown kicked in, cancel it.
pr:12345:powerokwait:/sbin/shutdown -c "Power Restored; Shutdown Cancelled"

# Run gettys in standard runlevels
3:2345:respawn:/sbin/getty 115200 ttySAC0



Can some experts suggest how to fix this two problems and get a shell
prompt working?
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