serial tty name

serial tty name

[Richard Zhao]

How to map different uart port to ttymxc0 (take imx for example)?

In rootfs, it usually "getty ttymxc0"  to get
serial console. And the rootfs may be shared by different boards.
Traditionaly way is to set right platform device ID.

But with DT, UART2 always generate ttymxc1, UART3 for ttymxc2. You
always needs to modify the getty command when your change another board.

Is there a way to fix it?


Thanks
Richard

serial tty name

[Igor Grinberg]

Hi Richard,

On 12/14/11 16:43, Richard Zhao wrote:
> How to map different uart port to ttymxc0 (take imx for example)?
> 
> In rootfs, it usually "getty ttymxc0"  to get
> serial console. And the rootfs may be shared by different boards.
> Traditionaly way is to set right platform device ID.
> 
> But with DT, UART2 always generate ttymxc1, UART3 for ttymxc2. You
> always needs to modify the getty command when your change another board.
> 
> Is there a way to fix it?

As for fix in userspace, you can spawn getty on every ttymxc*,
so you will get it always.

Another (userspace) fix would be:
Instead of getty, add a script (say getty.sh) which will do something like:
-----------
CONSOLE=`cat /proc/cmdline | tr " " "\n" | grep console= | tr "=" " " | tr "," " "`
TTY=`echo $CONSOLE | cut -d' ' -f 2`
SPEED=`echo $CONSOLE | cut -d' ' -f 3`

/sbin/getty -L $TTY $SPEED vt100
--------------

I use the above, because I have not just multiple boards,
but multiple platforms each with its own tty name...

-- 
Regards,
Igor.

serial tty name

[Rob Herring]

Richard,

On 12/14/2011 08:43 AM, Richard Zhao wrote:
> How to map different uart port to ttymxc0 (take imx for example)?
> 
> In rootfs, it usually "getty ttymxc0"  to get
> serial console. And the rootfs may be shared by different boards.
> Traditionaly way is to set right platform device ID.
> 
> But with DT, UART2 always generate ttymxc1, UART3 for ttymxc2. You
> always needs to modify the getty command when your change another board.
> 
> Is there a way to fix it?

That's what the aliases are for.

Rob

serial tty name

[Uwe Kleine-König]

On Wed, Dec 14, 2011 at 05:10:10PM +0200, Igor Grinberg wrote:
> Hi Richard,
> 
> On 12/14/11 16:43, Richard Zhao wrote:
> > How to map different uart port to ttymxc0 (take imx for example)?
> > 
> > In rootfs, it usually "getty ttymxc0"  to get
> > serial console. And the rootfs may be shared by different boards.
> > Traditionaly way is to set right platform device ID.
> > 
> > But with DT, UART2 always generate ttymxc1, UART3 for ttymxc2. You
> > always needs to modify the getty command when your change another board.
> > 
> > Is there a way to fix it?
> 
> As for fix in userspace, you can spawn getty on every ttymxc*,
> so you will get it always.
> 
> Another (userspace) fix would be:
> Instead of getty, add a script (say getty.sh) which will do something like:
> -----------
> CONSOLE=`cat /proc/cmdline | tr " " "\n" | grep console= | tr "=" " " | tr "," " "`
> TTY=`echo $CONSOLE | cut -d' ' -f 2`
> SPEED=`echo $CONSOLE | cut -d' ' -f 3`
> 
> /sbin/getty -L $TTY $SPEED vt100
> --------------

what about:

	eval "$(sed 's/.*console=\([^,]*\),\([0-9]*\).*/tty=\1; speed=\2/'" /proc/cmdline)"

this should prevent getting a "useless use of cat award".

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-K?nig            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

serial tty name

[Richard Zhao]

On Wed, Dec 14, 2011 at 09:31:59AM -0600, Rob Herring wrote:
> Richard,
> 
> On 12/14/2011 08:43 AM, Richard Zhao wrote:
> > How to map different uart port to ttymxc0 (take imx for example)?
> > 
> > In rootfs, it usually "getty ttymxc0"  to get
> > serial console. And the rootfs may be shared by different boards.
> > Traditionaly way is to set right platform device ID.
> > 
> > But with DT, UART2 always generate ttymxc1, UART3 for ttymxc2. You
> > always needs to modify the getty command when your change another board.
> > 
> > Is there a way to fix it?
> 
> That's what the aliases are for.
so, why do I see people define uart aliases in $SOC.dtsi, rather not in $BOARD.dts?

Thanks
Richard
> 
> Rob
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 

serial tty name

[Richard Zhao]

On Wed, Dec 14, 2011 at 07:33:41PM +0100, Uwe Kleine-K?nig wrote:
> On Wed, Dec 14, 2011 at 05:10:10PM +0200, Igor Grinberg wrote:
> > Hi Richard,
> > 
> > On 12/14/11 16:43, Richard Zhao wrote:
> > > How to map different uart port to ttymxc0 (take imx for example)?
> > > 
> > > In rootfs, it usually "getty ttymxc0"  to get
> > > serial console. And the rootfs may be shared by different boards.
> > > Traditionaly way is to set right platform device ID.
> > > 
> > > But with DT, UART2 always generate ttymxc1, UART3 for ttymxc2. You
> > > always needs to modify the getty command when your change another board.
> > > 
> > > Is there a way to fix it?
> > 
> > As for fix in userspace, you can spawn getty on every ttymxc*,
> > so you will get it always.
> > 
> > Another (userspace) fix would be:
> > Instead of getty, add a script (say getty.sh) which will do something like:
> > -----------
> > CONSOLE=`cat /proc/cmdline | tr " " "\n" | grep console= | tr "=" " " | tr "," " "`
> > TTY=`echo $CONSOLE | cut -d' ' -f 2`
> > SPEED=`echo $CONSOLE | cut -d' ' -f 3`
> > 
> > /sbin/getty -L $TTY $SPEED vt100
> > --------------
> 
> what about:
> 
> 	eval "$(sed 's/.*console=\([^,]*\),\([0-9]*\).*/tty=\1; speed=\2/'" /proc/cmdline)"
> 
> this should prevent getting a "useless use of cat award".
Thanks.
Richard
> 
> Best regards
> Uwe
> 
> -- 
> Pengutronix e.K.                           | Uwe Kleine-K?nig            |
> Industrial Linux Solutions                 | http://www.pengutronix.de/  |
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 

serial tty name

[Shawn Guo]

On Wed, Dec 14, 2011 at 10:43:47PM +0800, Richard Zhao wrote:
> How to map different uart port to ttymxc0 (take imx for example)?
> 
> In rootfs, it usually "getty ttymxc0"  to get
> serial console. And the rootfs may be shared by different boards.
> Traditionaly way is to set right platform device ID.
> 
> But with DT, UART2 always generate ttymxc1, UART3 for ttymxc2. You
> always needs to modify the getty command when your change another board.
> 
> Is there a way to fix it?
> 
I'm using Linaro rootfs and do not see this problem at all.  So as
people have suggested, you need to fix it in your user space.

-- 
Regards,
Shawn

serial tty name

[Shawn Guo]

On Wed, Dec 14, 2011 at 09:31:59AM -0600, Rob Herring wrote:
> Richard,
> 
> On 12/14/2011 08:43 AM, Richard Zhao wrote:
> > How to map different uart port to ttymxc0 (take imx for example)?
> > 
> > In rootfs, it usually "getty ttymxc0"  to get
> > serial console. And the rootfs may be shared by different boards.
> > Traditionaly way is to set right platform device ID.
> > 
> > But with DT, UART2 always generate ttymxc1, UART3 for ttymxc2. You
> > always needs to modify the getty command when your change another board.
> > 
> > Is there a way to fix it?
> 
> That's what the aliases are for.
> 
I understand it differently.  The aliases was introduced to help
tty/serial driver identify the correct hardware port for given serial
node from device tree.  (Ab)using it to fool 'console' setting may
eventually confuse users, saying they will think the uart port on his
board is UART0.

-- 
Regards,
Shawn

serial tty name

[Jason Liu]

2011/12/19 Shawn Guo <shawn.guo@freescale.com>:
> On Wed, Dec 14, 2011 at 09:31:59AM -0600, Rob Herring wrote:
>> Richard,
>>
>> On 12/14/2011 08:43 AM, Richard Zhao wrote:
>> > How to map different uart port to ttymxc0 (take imx for example)?
>> >
>> > In rootfs, it usually "getty ttymxc0" ?to get
>> > serial console. And the rootfs may be shared by different boards.
>> > Traditionaly way is to set right platform device ID.
>> >
>> > But with DT, UART2 always generate ttymxc1, UART3 for ttymxc2. You
>> > always needs to modify the getty command when your change another board.
>> >
>> > Is there a way to fix it?
>>
>> That's what the aliases are for.
>>
> I understand it differently. ?The aliases was introduced to help
> tty/serial driver identify the correct hardware port for given serial
> node from device tree. ?(Ab)using it to fool 'console' setting may
> eventually confuse users, saying they will think the uart port on his
> board is UART0.

We absolutely need document this in detail to avoid confusion. Otherwise,
the ARM DT support will also mess up in the end.

>
> --
> Regards,
> Shawn
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

serial tty name

[Richard Zhao]

On Mon, Dec 19, 2011 at 11:56:37AM +0800, Shawn Guo wrote:
> On Wed, Dec 14, 2011 at 10:43:47PM +0800, Richard Zhao wrote:
> > How to map different uart port to ttymxc0 (take imx for example)?
> > 
> > In rootfs, it usually "getty ttymxc0"  to get
> > serial console. And the rootfs may be shared by different boards.
> > Traditionaly way is to set right platform device ID.
> > 
> > But with DT, UART2 always generate ttymxc1, UART3 for ttymxc2. You
> > always needs to modify the getty command when your change another board.
> > 
> > Is there a way to fix it?
> > 
> I'm using Linaro rootfs and do not see this problem at all.  So as
> people have suggested, you need to fix it in your user space.
Why not past your linaro rootfs solution?

Thanks
Richard
> 
> -- 
> Regards,
> Shawn
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 

serial tty name

[Richard Zhao]

On Mon, Dec 19, 2011 at 12:49:11PM +0800, Jason Liu wrote:
> 2011/12/19 Shawn Guo <shawn.guo@freescale.com>:
> > On Wed, Dec 14, 2011 at 09:31:59AM -0600, Rob Herring wrote:
> >> Richard,
> >>
> >> On 12/14/2011 08:43 AM, Richard Zhao wrote:
> >> > How to map different uart port to ttymxc0 (take imx for example)?
> >> >
> >> > In rootfs, it usually "getty ttymxc0" ?to get
> >> > serial console. And the rootfs may be shared by different boards.
> >> > Traditionaly way is to set right platform device ID.
> >> >
> >> > But with DT, UART2 always generate ttymxc1, UART3 for ttymxc2. You
> >> > always needs to modify the getty command when your change another board.
> >> >
> >> > Is there a way to fix it?
> >>
> >> That's what the aliases are for.
> >>
> > I understand it differently. ?The aliases was introduced to help
> > tty/serial driver identify the correct hardware port for given serial
> > node from device tree. ?(Ab)using it to fool 'console' setting may
> > eventually confuse users, saying they will think the uart port on his
> > board is UART0.
> 
> We absolutely need document this in detail to avoid confusion. Otherwise,
> the ARM DT support will also mess up in the end.
Yes, why not come a patch to doc it?

THanks
Richard
> 
> >
> > --
> > Regards,
> > Shawn
> >
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel at lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 

serial tty name

[Shawn Guo]

On Mon, Dec 19, 2011 at 01:40:13PM +0800, Richard Zhao wrote:
> On Mon, Dec 19, 2011 at 11:56:37AM +0800, Shawn Guo wrote:
> > On Wed, Dec 14, 2011 at 10:43:47PM +0800, Richard Zhao wrote:
> > > How to map different uart port to ttymxc0 (take imx for example)?
> > > 
> > > In rootfs, it usually "getty ttymxc0"  to get
> > > serial console. And the rootfs may be shared by different boards.
> > > Traditionaly way is to set right platform device ID.
> > > 
> > > But with DT, UART2 always generate ttymxc1, UART3 for ttymxc2. You
> > > always needs to modify the getty command when your change another board.
> > > 
> > > Is there a way to fix it?
> > > 
> > I'm using Linaro rootfs and do not see this problem at all.  So as
> > people have suggested, you need to fix it in your user space.
> Why not past your linaro rootfs solution?
> 
You do have Linaro rootfs, don't you?

-- 
Regards,
Shawn