RE: Mini UART support for Raspberry Pi CM3 ?

["john@mobius-embedded-systems.co.uk" <andrew@mobius-embedded-systems.co.uk>]

Hi Ahmad

I got a little further and although there's still no serial output on UART1, I at least now see an error message about it (on UART0 still).  

ns16550_serial 3f215040.serial@7e215040.of: probe failed: Device or resource busy

So your point about setting CONSOLE_ACTIVATE_NONE was correct 😊.  Maybe I've missed something in the device trees, but am at least heartened to see something printed.  

Thanks

John

-----Original Message-----
From: barebox <barebox-bounces@lists.infradead.org> On Behalf Of Ahmad Fatoum
Sent: 02 June 2020 11:12
To: john@mobius-embedded-systems.co.uk <andrew@mobius-embedded-systems.co.uk>; barebox@lists.infradead.org
Subject: Re: Mini UART support for Raspberry Pi CM3 ?

On 6/2/20 11:57 AM, john@mobius-embedded-systems.co.uk wrote:
> Hi Ahmad
> 
> I have been using v2020.05 but I believe I had enabled all consoles so 
> I'll try setting it to none and see how that goes.

This will only fix the use of UART0 as output. To use UART1, you'll need to set stdout-path = &uart1 like ab76f9d09d3b ("ARM: rpi: choose miniuart as
stdout") does.

Cheers
Ahmad

> 
> Thanks
> 
> John
> 
> -----Original Message-----
> From: barebox <barebox-bounces@lists.infradead.org> On Behalf Of Ahmad 
> Fatoum
> Sent: 02 June 2020 10:55
> To: john@mobius-embedded-systems.co.uk
> <andrew@mobius-embedded-systems.co.uk>; barebox@lists.infradead.org
> Subject: Re: Mini UART support for Raspberry Pi CM3 ?
> 
> On 6/2/20 11:43 AM, Ahmad Fatoum wrote:
>> On 6/2/20 11:14 AM, john@mobius-embedded-systems.co.uk wrote:
>>> Hi
>>>
>>> I have been trying to get the mini UART (UART1) to work in Barebox 
>>> on the RPI Compute Module 3+.  I already have the changes made in 
>>> config.txt and this works fine when I boot into the main Linux code.
>>> However, in Barebox, the output always comes out on the main UART
>>> (UART0) and that is wired to the Bluetooth module on my platform.  I 
>>> have
> tried modifying the device
>>> trees and cannot seem to get any output.   I also ensured that I added
> the
>>> RPI CM3 output target as a config in rpi_defconfig.   
>>>
>>> I've tried turning off the PL011 config option and also changing the 
>>> device tree to reference UART1 and set the chosen stdout-path to 
>>> point to this UART, but when I do this I just get a lack of any 
>>> serial
> output.
>>>
>>> I am also wanting to use the alternate pins (32 & 33) for UART1, so 
>>> I am thinking that something else needs to be changed.  Has anyone 
>>> managed to get this to work?
>>
>> Which barebox version are you on? v2020.03.0 contains a series for 
>> mini UART support culminating in ab76f9d09d3b ("ARM: rpi: choose 
>> miniuart as stdout"), which sounds like something you will want to have.
> 
> Oh, I see now that this is in since v2019.03.0. I assume you are 
> already on a newer version?
> 
>> Also what's you "Console activation strategy"? (Kconfig symbols
>> CONSOLE_ACTIVATE_.*) You'll want to have CONSOLE_ACTIVATE_NONE, so 
>> only the stdout-path from the device tree is activated by default.
>>
>> Cheers
>> Ahmad
>>
>>>
>>> Regards
>>>
>>> John
>>>
>>>
>>> _______________________________________________
>>> barebox mailing list
>>> barebox@lists.infradead.org
>>> http://lists.infradead.org/mailman/listinfo/barebox
>>>
>>
> 

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