How to use earlycon and earlyprintk on Samsung S3C24xx

victorascroft at victorascroft at
Thu Feb 25 13:40:10 EST 2016


On 16-02-26 00:55:40, Woody Wu wrote:
> Hi,
> It seems, at least in 4.4.2 kernel, earlyprintk parameter supports
> something like 's3c24xx,<addr>'. But I dont know where to find out the addr
> value of the first uart port on my *s3c2416* based board.  Can someone
> please tell me?
> Also, I desire to know if the earlycon parameter supports the Samsung
> S3C24xx uarts, if so, what should the value of the parameter look like?

Have a look in the documentation here

The kernels kernel-parameter.txt documentation file lists the supported drivers. 

Generally the UART0 port is used for debugging but I guess there is
no such hard and fast rule.

For your particular board, you can check which UART port is used
as the debug serial console and then get the address for the concerned
UART by checking the relevant dtsi file in
arch/arm/boot/dts/s3c24xx.dtsi or perhaps one of the exynosX.dtsi files?

UART0 port seems to have address of 0x50000000?


> Thank in advance,
> -woody
> -- 
> Life is the only flaw in an otherwise perfect nonexistence
>     -- Schopenhauer
> woody
> public key at (narkewoody at

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