Mini UART support for Raspberry Pi CM3 ?

Mini UART support for Raspberry Pi CM3 ?

[john@mobius-embedded-systems.co.uk]

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?

Regards

John


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Re: Mini UART support for Raspberry Pi CM3 ?

[Ahmad Fatoum]

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.

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
> 

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
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Re: Mini UART support for Raspberry Pi CM3 ?

[Ahmad Fatoum]

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
>>
> 

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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RE: Mini UART support for Raspberry Pi CM3 ?

[john@mobius-embedded-systems.co.uk]

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.

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
>>
> 

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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Re: Mini UART support for Raspberry Pi CM3 ?

[Ahmad Fatoum]

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
>>>
>>
> 

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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barebox mailing list
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RE: Mini UART support for Raspberry Pi CM3 ?

[john@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
>>>
>>
> 

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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Re: Mini UART support for Raspberry Pi CM3 ?

[Ahmad Fatoum]

Hello,

On 6/4/20 12:14 AM, john@mobius-embedded-systems.co.uk wrote:
> 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
Drivers request the MMIO region they want to work with. Try the iomem command to see
if the EBUSY is due to a resource clash on 0x7e215040. Although I wonder how that
came about. Normally, with device tree, this shouldn't happen unless the device
tree is faulty.
> 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.  

Can't take credit, because I don't know why this would cause an error message to be
printed, when none was printed before.

Keep us posted.

Cheers
Ahmad

> 
> 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
>>>>
>>>
>>
> 

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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