[PATCH] bsps/raspberrypi/console: Fix default console device

[Alan Cudmore]

Hi Niteesh,
I was able to build the current RTEMS master (raspberrypi BSP) and I
was also able to successfully apply your patch and rebuild.
However, I am having trouble getting RTEMS running on the Raspberry Pis I have.
I tried it with and without the patch and I cannot get it to work. I
tried a Raspberry Pi Zero, B+, and Zero W ( with the patch).
I used these instructions for the firmware on SD card:
https://docs.rtems.org/branches/master/user/bsps/bsps-arm.html#raspberrypi

I tried:
- RTEMS master "arm/raspberrypi" BSP with and without the patch
- RTEMS 5 branch "arm/raspberrypi" BSP
- latest version of the RPI firmware files
- an older version of the RPI firmware (from June 2016)
I used the config.txt file that is recommended, but I did not have any
command line options. I did not have my raspberry Pis connected to
HDMI, only serial.

Can you describe your setup?
I know I have been through this before.

Thanks,
Alan

On Thu, May 6, 2021 at 10:48 AM Niteesh G. S. <niteesh.gs at gmail.com> wrote:
>
> Hi Alan,
>
> On Thu, May 6, 2021 at 6:12 PM Alan Cudmore <alan.cudmore at gmail.com> wrote:
>>
>> Hi Niteesh,
>>
>> I was hoping to try this out as soon as I get some time. No later than weekend. So if nobody else is able to check it out, I will be able to provide some feedback soon.
>>
>> I should be able to bring up the console on a RPi Zero W and RPi3, correct?
>
> the consoles should work on Zero W and Pi3 by default. They only fail to work when  CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER
> this option is used. This is because when that option is used it calls console_initialize which checks if any boot options were present if none were
> given it defaults to pl011 which is the secondary UART in Zero w and Pi3 so we get no output. This patch defaults to the primary UART instead of
> pl011 depending on the board.
> Also, this patch should be applied on RTEMS 5 since we started supporting Pi3 and Zero w from RTEMS 5.
>
> Thanks,
> Niteesh.
>
>
>>
>> Thanks,
>>
>> Alan
>>
>>
>>
>> From: Niteesh G. S.
>> Sent: Thursday, May 6, 2021 4:29 AM
>> To: Joel Sherrill; Christian Mauderer
>> Cc: rtems-devel at rtems.org
>> Subject: Re: [PATCH] bsps/raspberrypi/console: Fix default console device
>>
>>
>>
>> ping.
>>
>>
>>
>> On Sat, May 1, 2021 at 9:47 PM Niteesh G. S. <niteesh.gs at gmail.com> wrote:
>>
>> On Sat, May 1, 2021 at 8:31 PM Joel Sherrill <joel at rtems.org> wrote:
>>
>>
>>
>> On Sat, May 1, 2021, 8:53 AM Niteesh G. S. <niteesh.gs at gmail.com> wrote:
>>
>> Just to provide more context,
>>
>> When the CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER option is used
>>
>> and no --console option is provided, the console driver defaults to PL011.
>>
>> In raspberry pi 3 and other models whose primary UART is not PL011, we get no output.
>>
>> This patch fixes that by linking the primary UART to the console device.
>>
>>
>>
>> Thanks,
>>
>> Niteesh
>>
>>
>>
>> On Sat, May 1, 2021 at 7:05 PM G S Niteesh Babu <niteesh.gs at gmail.com> wrote:
>>
>> When no console argument is given, the driver defaults to pl011
>> this results in no output in case of Rpi3 whose primary uart is
>> miniuart.
>> This patch fixes that by defaulting to the primary uart when no
>> console option is provided.
>>
>>
>>
>> Does the default need to vary by model?
>>
>> Yes, the primary UART is different across models.
>>
>>
>>
>> Rpi's have two UARTs PL011 and miniuart, on models which have Bluetooth
>>
>> the PL011 is used to talk to the Bluetooth and miniuart acts as the primary UART.
>>
>> Now we can change this by adding miniuart-bt to config.txt but the miniuart is
>>
>> based on the VPU core and requires to add another option which sets the core to
>>
>> a fixed freq.
>>
>>
>>
>> ---
>>  bsps/arm/raspberrypi/console/console-config.c | 12 +++++++++---
>>  1 file changed, 9 insertions(+), 3 deletions(-)
>>
>> diff --git a/bsps/arm/raspberrypi/console/console-config.c b/bsps/arm/raspberrypi/console/console-config.c
>> index 6b8eb80aa4..bd3a8d34c2 100644
>> --- a/bsps/arm/raspberrypi/console/console-config.c
>> +++ b/bsps/arm/raspberrypi/console/console-config.c
>> @@ -165,10 +165,16 @@ static void console_select( void )
>>      }
>>    }else {
>>      /**
>> -     * If no command line option was given, default to PL011.
>> +     * If no console option was given we default to the primary uarts.
>> +     * The initialization of the uart's and BSP_output_char is already done
>> +     * in the uart_probe function called before this. So now we can safely
>> +     * compare BSP_output_char.
>>       */
>> -    BSP_output_char = output_char_pl011;
>> -    link(PL011, CONSOLE_DEVICE_NAME);
>> +    if (BSP_output_char == output_char_pl011) {
>> +      link(PL011, CONSOLE_DEVICE_NAME);
>> +    }else {
>> +      link(MINIUART, CONSOLE_DEVICE_NAME);
>> +    }
>>    }
>>  }
>>
>> --
>> 2.17.1
>>
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