how to get busybox shell prompt on console port?

how to get busybox shell prompt on console port?

[Robert P. J. Day]

  i'm still wrestling with how to get my 8xx-based board's shell
prompt to show up on the console port.  i've built a simple
2.6.11.7-based kernel and (busybox-based) root filesystem and, fairly
quickly, i realized i needed to use the following kernel boot line:

    Linux/PPC load: rw root=/dev/ram0 console=ttyCPM0,9600

  as the boot proceeds, i eventually see:

  Serial: CPM driver $Revision: 0.01 $
  ttyCPM0 at MMIO 0xfa200a80 (irq = 20) is a CPM UART
  ttyCPM1 at MMIO 0xfa200a00 (irq = 46) is a CPM UART

which seems to be a good sign.  however, after all the standard boot
output, i'm left with no shell prompt, and i'm assuming it's just
because i haven't correctly started the shell thru /etc/inittab with
the correct parameters to have it talk to that console port.

  what would be the correct invocation of /bin/sh in /etc/inittab to
reflect my serial/console port setup above?  thanks.

rday

Re: how to get busybox shell prompt on console port?

[Kylo Ginsberg]

I use this line in /etc/inittab (assuming you've built busybox to 
include sh):

ttyCPM0::respawn:-/bin/sh

Robert P. J. Day wrote:

>  i'm still wrestling with how to get my 8xx-based board's shell
>prompt to show up on the console port.  i've built a simple
>2.6.11.7-based kernel and (busybox-based) root filesystem and, fairly
>quickly, i realized i needed to use the following kernel boot line:
>
>    Linux/PPC load: rw root=/dev/ram0 console=ttyCPM0,9600
>
>  as the boot proceeds, i eventually see:
>
>  Serial: CPM driver $Revision: 0.01 $
>  ttyCPM0 at MMIO 0xfa200a80 (irq = 20) is a CPM UART
>  ttyCPM1 at MMIO 0xfa200a00 (irq = 46) is a CPM UART
>
>which seems to be a good sign.  however, after all the standard boot
>output, i'm left with no shell prompt, and i'm assuming it's just
>because i haven't correctly started the shell thru /etc/inittab with
>the correct parameters to have it talk to that console port.
>
>  what would be the correct invocation of /bin/sh in /etc/inittab to
>reflect my serial/console port setup above?  thanks.
>
>rday
>_______________________________________________
>Linuxppc-embedded mailing list
>Linuxppc-embedded@ozlabs.org
>https://ozlabs.org/mailman/listinfo/linuxppc-embedded
>
>  
>

Re: how to get busybox shell prompt on console port?

[Robert P. J. Day]

On Sun, 10 Apr 2005, Kylo Ginsberg wrote:

> I use this line in /etc/inittab (assuming you've built busybox to include sh):
>
> ttyCPM0::respawn:-/bin/sh

(first, a caveat: even though this is the 2.6 kernel, i'm still using
devfs for historical reasons.  that will change shortly but may be
part of my problems.)

i'm pretty sure i tried that combo, and several others like it, and i
finally had success with the following entry in /etc/inittab:

  ::respawn:/bin/sh < /dev/console > /dev/console 2> /dev/console

yes, it's disgusting but it works.  once i got a prompt, i noticed
that these are the contents of /dev:

crw-------    1 root     root     204,  46 Dec 31  1969 <NULL>0
crw-------    1 root     root     204,  47 Dec 31  1969 <NULL>1
crw-------    1 root     root       5,   1 Oct  2 08:56 console
crw-rw-rw-    1 root     root       1,   7 Dec 31  1969 full
drwxr-xr-x    1 root     root            0 Dec 31  1969 input
crw-r-----    1 root     root       1,   2 Dec 31  1969 kmem
crw-r--r--    1 root     root       1,  11 Dec 31  1969 kmsg
drwxr-xr-x    1 root     root            0 Dec 31  1969 loop
crw-r-----    1 root     root       1,   1 Dec 31  1969 mem
drwxr-xr-x    1 root     root            0 Dec 31  1969 misc
crw-rw-rw-    1 root     root       1,   3 Dec 31  1969 null
crw-r-----    1 root     root       1,   4 Dec 31  1969 port
crw-rw-rw-    1 root     root       5,   2 Dec 31  1969 ptmx
drwxr-xr-x    1 root     root            0 Dec 31  1969 pts
drwxr-xr-x    1 root     root            0 Dec 31  1969 pty
crw-r--r--    1 root     root       1,   8 Dec 31  1969 random
drwxr-xr-x    1 root     root            0 Dec 31  1969 rd
lr-xr-xr-x    1 root     root            4 Sep 25  1969 root -> rd/0
drwxr-xr-x    1 root     root            0 Dec 31  1969 shm
crw-rw-rw-    1 root     root       5,   0 Dec 31  1969 tty
crw-r--r--    1 root     root       1,   9 Dec 31  1969 urandom
crw-rw-rw-    1 root     root       1,   5 Dec 31  1969 zero


  in other words, no /dev/ttyCPM0 which may be why that first solution
never worked (i'm still fuzzy on support for the serial/console ports
so i'm reading up on that now.)  but given that i have a /dev/console,
i'll stick with that for now until i have a better fix.

  and what's the two "NULL" entries up there?  those are new to me.

rday

Re: how to get busybox shell prompt on console port?

[Kylo Ginsberg]

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Re: how to get busybox shell prompt on console port?

[Robert P. J. Day]

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On Sun, 10 Apr 2005, Kylo Ginsberg wrote:

> Fwiw, I explicitly created the CPM devices; note that the
> major/minor match those of your NULL nodes.  I'm running 2.6.11. 
> I'm fuzzy re if/how these devices should be automagically created by
> the kernel.
>
>  mknod ttyCPM0 c 204 46
>   mknod ttyCPM1 c 204 47
>   chmod 660 ttyCPM*
>
...
> crw-------    1 root     root     204,  46 Dec 31  1969 <NULL>0
> crw-------    1 root     root     204,  47 Dec 31  1969 <NULL>1

well, since i'm using devfs, i'm assuming that's what i get by
default.  ok, that clears up some of the confusion.  thanks.

rday