[U-Boot] [PATCH v3 5/6] arm: debug: add Kconfig entries for lowlevel debug

[Simon Glass]

Hi Masahiro,

On 31 August 2014 20:06, Masahiro Yamada <yamada.m at jp.panasonic.com> wrote:
> We have not had a good method to debug the early boot stage such as
> lowlevel_init function.  I guess developers generally use dedicated
> debuggers for that, but it is difficult in some cases.
> (For example, my debugger cannot connect to the ARM processor when
> it is in the secure state.  It sometimes happens when I need to
> debug the early boot stage on ARM SoCs with secure extension.)
>
> The low level debug feature in Linux would be also helpful for U-boot
> when we are stucking in nasty problems where the console is not
> available yet.
>
> You have to enable CONFIG_DEBUG_LL to use this feature.
> For now, only 8250-compatible UART devices are supported.
> You can add a header file under arch/arm/include/debug/ directory
> to support your UART device if necessary.
>
> Signed-off-by: Masahiro Yamada <yamada.m at jp.panasonic.com>

Is it possible to use the existing drivers for this? It seems
unfortunate to duplicate the ns16550 driver (if that is what has
happened).

E.g. I have had good luck just calling that driver code directly. I'm
not sure of an overall framework but it must be possible...

Regards,
Simon