[yocto] thud, beaglebone-yocto.conf: SERIAL_CONSOLES setting

[Bruce Ashfield]

On 2018-11-02 4:59 AM, Kevin Hao wrote:
> On Fri, Nov 02, 2018 at 09:01:34AM +0100, Heiko Schocher wrote:
>> Hello Kevin,
>>
>> Am 01.11.2018 um 03:18 schrieb Kevin Hao:
>>> On Wed, Oct 31, 2018 at 02:23:00PM +0100, Heiko Schocher wrote:
>>>> Hello all,
>>>>
>>>> just builded core-image-minimal with current head of thud branch for
>>>> the beaglebone-yocto machine, with linux 4.14.x LTS "Linux version 4.14.78",
>>>> installed the resulting sd card image and boot it, and get:
>>>>
>>>> INIT: Id "O0" respawning too fast: disabled for
>>>> 5 minutes
>>>>
>>>> Reason seems to be:
>>>>
>>>> meta-yocto-bsp/conf/machine/beaglebone-yocto.conf
>>>>
>>>> SERIAL_CONSOLES = "115200;ttyO0"
>>>>
>>>> shouldn't this be
>>>>
>>>> SERIAL_CONSOLES = "115200;ttyS0"
>>>>
>>>> With this fix, sd card image boot fine ... may I oversee seomthing
>>>> obvious ?
>>>
>>> No, it should be 'ttyO0'. It is set by the omap serial driver. You can
>>> refer the following in platform_data/serial-omap.h:
>>>     #define OMAP_SERIAL_NAME        "ttyO"
>>
>> Yes, you are right, but I see with linux kernel 4.14.78 from
>>
>> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-4.14.y&id=e7405910ca5553eae8744af4e5c03e64ee048cb1
>>
>> and I see:
>>
>> [    0.000000] Linux version 4.14.78 (oe-user at oe-host) (gcc version 8.2.0
>> (GCC)) #1 Thu Nov 1 10:51:09 UTC 2018
>> [    0.000000] CPU: ARMv7 Processor [413fc082] revision 2 (ARMv7), cr=10c5387d
>> [    0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
>> [    0.000000] OF: fdt: Machine model: TI AM335x BeagleBone Black
>> [...]
>> [    0.362878] Serial: 8250/16550 driver, 6 ports, IRQ sharing disabled
>> [    0.365758] 44e09000.serial: ttyS0 at MMIO 0x44e09000 (irq = 30, base_baud = 3000000) is a 8250
>> [    1.030465] console [ttyS0] enabled
>>
>> So definitely a ttyS0 ...
> 
> OK, so you don't use the linux-yocto kernel, you must not use the Yocto kernel
> meta either. The reason that you got a ttyS0 here is that you use the
> 8250_omap.c driver. But in Yocto we use the omap-serial.c driver. You can
> workaround this issue by enabling SERIAL_8250_OMAP_TTYO_FIXUP.

Thanks Kevin!

I had missed that detail in my reply.

Bruce

> 
> Thanks,
> Kevin
> 
>>
>> bye,
>> Heiko
>>>
>>> Thanks,
>>> Kevin
>>>
>>>>
>>>> bye,
>>>> Heiko
>>>> -- 
>>>> DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
>>>> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
>>>> Phone: +49-8142-66989-52   Fax: +49-8142-66989-80   Email: hs at denx.de
>>>> -- 
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>>
>> -- 
>> DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
>> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
>> Phone: +49-8142-66989-52   Fax: +49-8142-66989-80   Email: hs at denx.de
>>
>>