serial port multiplexing

serial port multiplexing

[Rahul Tank]

 Hello all,

    I am a newbee tryinging for serial port
multiplexing. Currently my driver supports for one
port
(/dev/ttyS0). However i want to use the same physical
port for 2 virtual ports.I am NOT sending two type of
data simultaneously. I want to first reigister my
driver for /dev/ttyS0. When the kernel  has booted ,i
want to disable it. Then i want to enable the driver
to register for say /dev/ttyS1.
  in short i don't want the console to have controle
over the serial port.
  The point of doing such is that i want my serial
port to be free. I can telnet to this potr from other
machine and test few stuff. i hope i have properly
mentioned my problem.

 plz let me know how should i proceed.
 thanks in advance.

 regards,
  rahul





	

	
		
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Re: serial port multiplexing

[Russell King]

On Thu, Aug 25, 2005 at 01:20:45PM +0100, Rahul Tank wrote:
>     I am a newbee tryinging for serial port
> multiplexing. Currently my driver supports for one
> port
> (/dev/ttyS0). However i want to use the same physical
> port for 2 virtual ports.I am NOT sending two type of
> data simultaneously. I want to first reigister my
> driver for /dev/ttyS0. When the kernel  has booted ,i
> want to disable it. Then i want to enable the driver
> to register for say /dev/ttyS1.
>   in short i don't want the console to have controle
> over the serial port.

Try setting the kernel message level to zero after boot.  That
will prevent the kernel from displaying any further messages to
that serial port, except when a serious problem (eg, oops) occurs.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core

Re: serial port multiplexing

[Jan-Benedict Glaw]

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On Wed, 2005-08-31 11:10:48 +0100, Russell King <rmk+lkml@arm.linux.org.uk> wrote:
> On Thu, Aug 25, 2005 at 01:20:45PM +0100, Rahul Tank wrote:
> >     I am a newbee tryinging for serial port
> > multiplexing. Currently my driver supports for one
> > port
> > (/dev/ttyS0). However i want to use the same physical
> > port for 2 virtual ports.I am NOT sending two type of
> > data simultaneously. I want to first reigister my
> > driver for /dev/ttyS0. When the kernel  has booted ,i
> > want to disable it. Then i want to enable the driver
> > to register for say /dev/ttyS1.
> >   in short i don't want the console to have controle
> > over the serial port.
> 
> Try setting the kernel message level to zero after boot.  That
> will prevent the kernel from displaying any further messages to
> that serial port, except when a serious problem (eg, oops) occurs.

Alternatively, IIRC one of the printk-nullifying patches were taken
some time ago. You should be able to eleminate any printk()s through
kernel configuration in the embedded menu.

MfG, JBG

-- 
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Re: serial port multiplexing

[Russell King]

On Wed, Aug 31, 2005 at 12:16:10PM +0200, Jan-Benedict Glaw wrote:
> On Wed, 2005-08-31 11:10:48 +0100, Russell King <rmk+lkml@arm.linux.org.uk> wrote:
> > On Thu, Aug 25, 2005 at 01:20:45PM +0100, Rahul Tank wrote:
> > >     I am a newbee tryinging for serial port
> > > multiplexing. Currently my driver supports for one
> > > port
> > > (/dev/ttyS0). However i want to use the same physical
> > > port for 2 virtual ports.I am NOT sending two type of
> > > data simultaneously. I want to first reigister my
> > > driver for /dev/ttyS0. When the kernel  has booted ,i
> > > want to disable it. Then i want to enable the driver
> > > to register for say /dev/ttyS1.
> > >   in short i don't want the console to have controle
> > > over the serial port.
> > 
> > Try setting the kernel message level to zero after boot.  That
> > will prevent the kernel from displaying any further messages to
> > that serial port, except when a serious problem (eg, oops) occurs.
> 
> Alternatively, IIRC one of the printk-nullifying patches were taken
> some time ago. You should be able to eleminate any printk()s through
> kernel configuration in the embedded menu.

Yes, except I believe the OP wants to see the initial kernel messages,
and then want to shut the kernel up once it has booted.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core