On Tue, Feb 03, 2015 at 01:10:57AM +0300, Sergei Shtylyov wrote:

Hello.

On 01/31/2015 07:17 AM, Simon Horman wrote:

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Alt is booted from DT, so chosen/stdout-path is
always used, and we can drop the "console=" parameter from chosen/bootargs.

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This change has a side-effect of changing the console speed from 38400
to 115200. This is intentional as 115200 is consistently used on
all other shmobile boards.

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   I'd say it's not very practical to change the console's baud rate from
U-Boot's default

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It is consistent with the handling of all other boards with
renesas SoCs that are present in mainline.

   Well, not quite: Henninger/Porter is still using 38400.

From my point of view that is an oversight which I would have

resolved had I ever obtained access to the hardware.

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(AFAIR changing baud rate in U-Boot didn't work)...

   That was a recollection from the other board though, I haven't yet tried
to do it on the SILK board (and I'm unable to currently as the power supply
seems dead).

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Perhaps that relates to the version of built of uboot.
On the board I have access to I see:

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ver=U-Boot 2013.01.01-g5df9446 (Oct 01 2014 - 14:59:23)

U-Boot 2013.01.01 (Oct 17 2014 - 20:59:18)

It looks like my version has some extra patches (the g5df9446 bit).
But I could be reading things wrong.

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And the following setting altered the baud rate of u-boot (IIRC).

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baudrate=115200

   I was going to try that but the board just didn't power up.

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Cc: Ulrich Hecht <redacted>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: devicetree at vger.kernel.org
Signed-off-by: Simon Horman <redacted>
---
 arch/arm/boot/dts/r8a7794-alt.dts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

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diff --git a/arch/arm/boot/dts/r8a7794-alt.dts b/arch/arm/boot/dts/r8a7794-alt.dts
index 8aec512..f2cf757 100644
--- a/arch/arm/boot/dts/r8a7794-alt.dts
+++ b/arch/arm/boot/dts/r8a7794-alt.dts

@@ -20,7 +20,7 @@
 	};

 	chosen {
-		bootargs = "console=ttySC0,38400 ignore_loglevel rw root=/dev/nfs ip=dhcp";
+		bootargs = "ignore_loglevel rw root=/dev/nfs ip=dhcp";

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   Hm, does this even work as intended? I've tried to boot another R8A7794
based board and I couldn't get any output with alike command line. Booting
with 'earlyprintk=serial' has shown that tty0 was enabled as a console which
is not what we wanted.

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If you are backporting this change then I believe it has some dependencies
that I can follow up on if it is useful to you.

   Contrariwise, I'm forward-porting.

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If you are using mainline (e.g. next or renesas-next) then yes,
it works. I have tested it numerous times since the patch was merged.

   I'm traditionally using the 'renesas-devel-*' tags.

If you are using 'renesas-devel-*' tags (and forward porting) then
you should be in good shape. But if you would like me to verify a particular
tag I'm happy to do so. It is not unheard of for different instances of
the same board behave in different ways.