Re: [PATCH] arm: mvebu: a38x: Define supported UART baudrates

[Stefan Roese <sr@denx.de>]

On 11.08.21 10:08, Pali Rohár wrote:
> Define all standard baudrates plus 3 non-standard high speed:
> 3125000 4000000 5150000
> 
> 3125000 matches divisor 5 with 250 MHz TCLK and divisor 4 with 200 MHz TCLK.
> 4000000 is the rounded value for divisor 4 with 250 MHz TCLK (3906250) and
> divisor 3 with 200 MHz TCLK (4166666).
> 
> 5150000 is the rounded value (5208333) for divisor 3 with 250 MHz TCLK.
> Testing showed that rounded value is more stable then exactly calculated.
> And it is the highest possible baudrate which is stable on A38x platform.
> 
> Any other baudrate values above 2500000 are unstable, which is reason why
> e.g. standard value 3000000 is not defined, and it is needed to use
> non-standard value 3125000.
> 
> Tested all defined UART baudrates on Turris Omnia (A38x with 250 MHz TCLK).
> 
> Signed-off-by: Pali Rohár <pali@kernel.org>

Reviewed-by: Stefan Roese <sr@denx.de>

Thanks,
Stefan

> ---
>   include/configs/mv-common.h | 9 +++++++++
>   1 file changed, 9 insertions(+)
> 
> diff --git a/include/configs/mv-common.h b/include/configs/mv-common.h
> index d61c90a43156..53d7acbb1034 100644
> --- a/include/configs/mv-common.h
> +++ b/include/configs/mv-common.h
> @@ -39,6 +39,15 @@
>   #define CONFIG_SYS_NS16550_COM1		MV_UART_CONSOLE_BASE
>   #endif
>   
> +#if defined(CONFIG_ARMADA_38X) && !defined(CONFIG_SYS_BAUDRATE_TABLE)
> +#define CONFIG_SYS_BAUDRATE_TABLE	{ 300, 600, 1200, 1800, 2400, 4800, \
> +					  9600, 19200, 38400, 57600, 115200, \
> +					  230400, 460800, 500000, 576000, \
> +					  921600, 1000000, 1152000, 1500000, \
> +					  2000000, 2500000, 3125000, 4000000, \
> +					  5150000 }
> +#endif
> +
>   /* auto boot */
>   
>   /*
> 


Viele Grüße,
Stefan

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