rootfs issue in kernel porting - FPGA board [/bin/sh: can't access tty; job control turned off]

[pcuser p]

Hi,
I am doing  linux kernel porting for FPGA board.
I am facing issue in getting the shell prompt at the end of kernel booting.
Shell prompt is not taking any commands I’m typing.

I can place break point in Tx & Rx ISR with Jtag debugger.ISR functions
seems working till shell is entered (echo message in the /etc/inittab
script & mounting /proc,/devtmpfs and ls command (added to check)are
working, I added ls,cat command in the /etc/init.d/rcS file to check uart
Tx / Rx)

Once the shell is entered with the below message, UART ISR is NOT invoked
(using JTAG to put breakpoints) ,if I type any command & I can’t get any
message.


*Err message:

/bin/sh: can't access tty; job control turned off

/ #*



Kindly share  any suggestion to fix this issue.
*
Below are the /etc/initab & /etc/init.d/rcS *

/etc/inittab:

# This is run first script

::sysinit:/etc/init.d/rcS



# Start an "askfirst" shell on the console

ttySAC0::askfirst:-/bin/sh

ttySAC0::respawn:-/sbin/getty 115200 ttySAC0



# Stuff to do when restarting the init process

::restart:/sbin/init



# Stuff to do before rebooting

::ctrlaltdel:/sbin/reboot

::shutdown:/bin/umount ­a ­r







*/etc/init.d/rcS*

#!/bin/sh

echo -e "\n in rcS script\n"

echo -e "\n Mounting proc FS\n"

mount ­t proc none /proc

echo -e "\nMounting sysfs \n"

mount ­t sysfs none /sys

ls -alh /

echo -e "\n\n"

ls -alh /dev/ttyS*

echo -e "\n"

cat /proc/interrupts

echo -e "\n ttySAC0 respawning \n"

ttySAC0::respawn:-/sbin/getty 115200 ttySAC0

echo -e "\n ttySAC0 respawning finished \n"

echo -e "\n exec /bin/sh\n"

exec /bin/sh

ls

#ls -alh /dev

*Below are the console message of boot up.*

Linux version 3.1.6-00011-g82af784-dirty (pcuser at pcuser-linux) (gcc version
4.6.1 (Ubuntu/Linaro 4.6.1-9ubuntu3) ) #66 Fri May 11 16:21:22 IST 2012
CPU: ARM926EJ-S [41069265] revision 5 (ARMv5TEJ), cr=00053177
CPU: VIVT data cache, VIVT instruction cache
Machine: FPGA Board
Memory policy: ECC disabled, Data cache writeback
Available lowmem size : 32 MB
Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 8128
Kernel command line: mem=32M console=ttySAC0,115200 root=/dev/ram0
init=/sbin/init initrd=0x80800000,8M user_debug=31
PID hash table entries: 128 (order: -3, 512 bytes)
Dentry cache hash table entries: 4096 (order: 2, 16384 bytes)
Inode-cache hash table entries: 2048 (order: 1, 8192 bytes)
Memory: 32MB = 32MB total
Memory: 22456k/22456k available, 10312k reserved, 0K highmem
Virtual kernel memory layout:
    vector  : 0xffff0000 - 0xffff1000   (   4 kB)
    fixmap  : 0xfff00000 - 0xfffe0000   ( 896 kB)
    DMA     : 0xffc00000 - 0xffe00000   (   2 MB)
    vmalloc : 0xc2800000 - 0xf6000000   ( 824 MB)
    lowmem  : 0xc0000000 - 0xc2000000   (  32 MB)
    modules : 0xbf000000 - 0xc0000000   (  16 MB)
      .text : 0xc0008000 - 0xc018c000   (1552 kB)
      .init : 0xc018c000 - 0xc01a1000   (  84 kB)
      .data : 0xc01a2000 - 0xc01afe00   (  56 kB)
       .bss : 0xc01afe24 - 0xc01c0f24   (  69 kB)
SLUB: Genslabs=13, HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
NR_IRQS:32
Console: colour dummy device 80x30
console [ttySAC0] enabled
Calibrating delay loop... 1.86 BogoMIPS (lpj=9344)
pid_max: default: 32768 minimum: 301
Mount-cache hash table entries: 512
CPU: Testing write buffer coherency: ok
devtmpfs: initialized
exceptions_init
Switching to clocksource timer0
Trying to unpack rootfs image as initramfs...
rootfs image is not initramfs (junk in compressed archive); looks like an
initrd
Freeing initrd memory: 8192K
msgmni has been set to 59
io scheduler noop registered (default)
brd: module loaded
loop: module loaded
mousedev: PS/2 mouse device common for all mice
RAMDISK: ext2 filesystem found at block 0
RAMDISK: Loading 3072KiB [1 disk] into ram disk... \
done.
VFS: Mounted root (ext2 filesystem) readonly on device 1:0.
devtmpfs: mounted
Freeing init memory: 84K

*echo messages from /etc/rcS & /etc/inintab*
 in rcS script

 Mounting proc FS

Mounting sysfs

drwxrwxr-x   12 0        0           1.0K May  9  2012 .
drwxrwxr-x   12 0        0           1.0K May  9  2012 ..
drwxrwxr-x    2 0        0           2.0K May 11  2012 bin
drwxr-xr-x    3 0        0          11.9K Jan  1 00:00 dev
drwxr-xr-x    3 0        0           1.0K May 11  2012 etc
drwxr-xr-x    2 0        0           1.0K May  9  2012 lib
lrwxrwxrwx    1 0        0             11 May  8  2012 linuxrc ->
bin/busybox
drwx------    2 0        0          12.0K May  8  2012 lost+found
drwxr-xr-x    2 0        0           1.0K May  8  2012 proc
drwxrwxr-x    2 0        0           1.0K May  8  2012 sbin
drwxr-xr-x    2 0        0           1.0K May  8  2012 sys
drwxrwxr-x    4 0        0           1.0K May  8  2012 usr
drwxr-xr-x    2 0        0           1.0K May  9  2012 var


crw-------    1 0        0         204,  64 Jan  1 00:00 /dev/ttySAC0



 ttySAC0 respawning

/etc/init.d/rcS: line 20: ttySAC0::respawn:-/sbin/getty: not found

 ttySAC0 respawning finished

-rwxr-xr-x    1 0        0           1.0K May 11  2012 /bin/hello

calling hello world

/etc/init.d/rcS: line 24: ./hello: not found
/etc/init.d/rcS: line 25: hello: not found
/etc/init.d/rcS: line 26: ./hello: not found
/etc/init.d/rcS: line 27: /bin/hello: not found

 exec /bin/sh

/bin/sh: can't access tty; job control turned off
/ #

I can't type any commad at the shell prompt,
shell  is not accepting it.
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