[PATCH] ARM: dts: mvebu: Fix armada-385-turris-omnia stdout-path

[PATCH] ARM: dts: mvebu: Fix armada-385-turris-omnia stdout-path

[Andreas Färber]

Specify the baudrate.

Fixes: 26ca8b52d6e1 ("ARM: dts: add support for Turris Omnia")
Cc: Uwe Kleine-König <uwe@kleine-koenig.org>
Signed-off-by: Andreas Färber <afaerber@suse.de>
---
 arch/arm/boot/dts/armada-385-turris-omnia.dts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/boot/dts/armada-385-turris-omnia.dts b/arch/arm/boot/dts/armada-385-turris-omnia.dts
index f53cb8b73610..2eff012287d4 100644
--- a/arch/arm/boot/dts/armada-385-turris-omnia.dts
+++ b/arch/arm/boot/dts/armada-385-turris-omnia.dts
@@ -52,7 +52,7 @@
 	compatible = "cznic,turris-omnia", "marvell,armada385", "marvell,armada380";
 
 	chosen {
-		stdout-path = &uart0;
+		stdout-path = "serial0:115200n8";
 	};
 
 	memory {
-- 
2.6.6

Re: [PATCH] ARM: dts: mvebu: Fix armada-385-turris-omnia stdout-path

[Andrew Lunn]

On Sun, Nov 27, 2016 at 08:37:24PM +0100, Andreas Färber wrote:
> Specify the baudrate.

Hi Andreas

Please put each patch/patchset in a new thread.

> Fixes: 26ca8b52d6e1 ("ARM: dts: add support for Turris Omnia")
> Cc: Uwe Kleine-König <uwe@kleine-koenig.org>
> Signed-off-by: Andreas Färber <afaerber@suse.de>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew

Re: [PATCH] ARM: dts: mvebu: Fix armada-385-turris-omnia stdout-path

[Uwe Kleine-König]

On Sun, Nov 27, 2016 at 08:37:24PM +0100, Andreas Färber wrote:
> Specify the baudrate.
> 
> Fixes: 26ca8b52d6e1 ("ARM: dts: add support for Turris Omnia")
> Cc: Uwe Kleine-König <uwe@kleine-koenig.org>
> Signed-off-by: Andreas Färber <afaerber@suse.de>

You said with plain &uart0 the kernel uses a wrong baud rate? That's
strange. For me it works and I think it's the intended behaviour to
dermine the baud rate setup by the bootloader and use this.

I'd prefer it this way over hard coding the baud rate.

>  arch/arm/boot/dts/armada-385-turris-omnia.dts | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm/boot/dts/armada-385-turris-omnia.dts b/arch/arm/boot/dts/armada-385-turris-omnia.dts
> index f53cb8b73610..2eff012287d4 100644
> --- a/arch/arm/boot/dts/armada-385-turris-omnia.dts
> +++ b/arch/arm/boot/dts/armada-385-turris-omnia.dts
> @@ -52,7 +52,7 @@
>  	compatible = "cznic,turris-omnia", "marvell,armada385", "marvell,armada380";
>  
>  	chosen {
> -		stdout-path = &uart0;
> +		stdout-path = "serial0:115200n8";
>  	};
>  
>  	memory {

This has the downside to depend on the alias. Not sure this is
considered modern. An alternative would be:

	stdout-path = "/soc/internal-regs/serial@12000:115200n8";

(maybe there even exists syntactic sugar to express this using &uart0?)

Best regards
Uwe

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

Re: [PATCH] ARM: dts: mvebu: Fix armada-385-turris-omnia stdout-path

[Andreas Färber]

Am 27.11.2016 um 22:25 schrieb Uwe Kleine-König:
> On Sun, Nov 27, 2016 at 08:37:24PM +0100, Andreas Färber wrote:
>> Specify the baudrate.
>>
>> Fixes: 26ca8b52d6e1 ("ARM: dts: add support for Turris Omnia")
>> Cc: Uwe Kleine-König <uwe@kleine-koenig.org>
>> Signed-off-by: Andreas Färber <afaerber@suse.de>
> 
> You said with plain &uart0 the kernel uses a wrong baud rate? That's
> strange. For me it works and I think it's the intended behaviour to
> dermine the baud rate setup by the bootloader and use this.

IIRC the 8250 driver defaults to 9600n8 if unspecified.

Kernel tested: 4.9.0-rc2-next-20161028-00010-g4fb44d9-dirty

Maybe you used some console= argument overriding it?

> I'd prefer it this way over hard coding the baud rate.
> 
>>  arch/arm/boot/dts/armada-385-turris-omnia.dts | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/arm/boot/dts/armada-385-turris-omnia.dts b/arch/arm/boot/dts/armada-385-turris-omnia.dts
>> index f53cb8b73610..2eff012287d4 100644
>> --- a/arch/arm/boot/dts/armada-385-turris-omnia.dts
>> +++ b/arch/arm/boot/dts/armada-385-turris-omnia.dts
>> @@ -52,7 +52,7 @@
>>  	compatible = "cznic,turris-omnia", "marvell,armada385", "marvell,armada380";
>>  
>>  	chosen {
>> -		stdout-path = &uart0;
>> +		stdout-path = "serial0:115200n8";
>>  	};
>>  
>>  	memory {
> 
> This has the downside to depend on the alias. Not sure this is
> considered modern. An alternative would be:
> 
> 	stdout-path = "/soc/internal-regs/serial@12000:115200n8";

Please don't unroll the path I'm trying to abstract elsewhere.

Like I said, the "serialX:115200n8" syntax is what all other Armada 38x
boards use:

git grep stdout-path -- arch/arm/boot/dts/ | grep armada-38
arch/arm/boot/dts/armada-385-db-ap.dts:		stdout-path = "serial1:115200n8";
arch/arm/boot/dts/armada-385-linksys.dtsi:		stdout-path =
"serial0:115200n8";
arch/arm/boot/dts/armada-388-clearfog.dts:		stdout-path =
"serial0:115200n8";
arch/arm/boot/dts/armada-388-db.dts:		stdout-path = "serial0:115200n8";
arch/arm/boot/dts/armada-388-gp.dts:		stdout-path = "serial0:115200n8";
arch/arm/boot/dts/armada-388-rd.dts:		stdout-path = "serial0:115200n8";

The alias is needed to reliably determine the tty device number and is
set "globally" in armada-38x.dtsi, so why is it a problem to rely on?

Regards,
Andreas

> 
> (maybe there even exists syntactic sugar to express this using &uart0?)

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SUSE Linux GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
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HRB 21284 (AG Nürnberg)

Re: [PATCH] ARM: dts: mvebu: Fix armada-385-turris-omnia stdout-path

[Uwe Kleine-König]

Hello,

On Sun, Nov 27, 2016 at 11:14:37PM +0100, Andreas Färber wrote:
> Am 27.11.2016 um 22:25 schrieb Uwe Kleine-König:
> > On Sun, Nov 27, 2016 at 08:37:24PM +0100, Andreas Färber wrote:
> >> Specify the baudrate.
> >>
> >> Fixes: 26ca8b52d6e1 ("ARM: dts: add support for Turris Omnia")
> >> Cc: Uwe Kleine-König <uwe@kleine-koenig.org>
> >> Signed-off-by: Andreas Färber <afaerber@suse.de>
> > 
> > You said with plain &uart0 the kernel uses a wrong baud rate? That's
> > strange. For me it works and I think it's the intended behaviour to
> > dermine the baud rate setup by the bootloader and use this.
> 
> IIRC the 8250 driver defaults to 9600n8 if unspecified.
> 
> Kernel tested: 4.9.0-rc2-next-20161028-00010-g4fb44d9-dirty
> 
> Maybe you used some console= argument overriding it?

Yes, you're right.

> > I'd prefer it this way over hard coding the baud rate.
> > 
> >>  arch/arm/boot/dts/armada-385-turris-omnia.dts | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/arch/arm/boot/dts/armada-385-turris-omnia.dts b/arch/arm/boot/dts/armada-385-turris-omnia.dts
> >> index f53cb8b73610..2eff012287d4 100644
> >> --- a/arch/arm/boot/dts/armada-385-turris-omnia.dts
> >> +++ b/arch/arm/boot/dts/armada-385-turris-omnia.dts
> >> @@ -52,7 +52,7 @@
> >>  	compatible = "cznic,turris-omnia", "marvell,armada385", "marvell,armada380";
> >>  
> >>  	chosen {
> >> -		stdout-path = &uart0;
> >> +		stdout-path = "serial0:115200n8";
> >>  	};
> >>  
> >>  	memory {
> > 
> > This has the downside to depend on the alias. Not sure this is
> > considered modern. An alternative would be:
> > 
> > 	stdout-path = "/soc/internal-regs/serial@12000:115200n8";
> 
> Please don't unroll the path I'm trying to abstract elsewhere.

Yeah, specifying the path isn't nice.

> Like I said, the "serialX:115200n8" syntax is what all other Armada 38x
> boards use:

This isn't a reason to not think about better alternatives. An if
something like:

	stdout-path = &uart0 + ":115200n8";

would be possible, I'd definitely prefer it over "serial0:115200n8".

> git grep stdout-path -- arch/arm/boot/dts/ | grep armada-38
> arch/arm/boot/dts/armada-385-db-ap.dts:		stdout-path = "serial1:115200n8";
> arch/arm/boot/dts/armada-385-linksys.dtsi:		stdout-path =
> "serial0:115200n8";
> arch/arm/boot/dts/armada-388-clearfog.dts:		stdout-path =
> "serial0:115200n8";
> arch/arm/boot/dts/armada-388-db.dts:		stdout-path = "serial0:115200n8";
> arch/arm/boot/dts/armada-388-gp.dts:		stdout-path = "serial0:115200n8";
> arch/arm/boot/dts/armada-388-rd.dts:		stdout-path = "serial0:115200n8";
> 
> The alias is needed to reliably determine the tty device number and is
> set "globally" in armada-38x.dtsi, so why is it a problem to rely on?

AFAIK aliases are seen as (still necessary) evil by the dt people. So if
you can stop making use of them, that would be nice.

Best regards
Uwe

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