[U-Boot] [PATCH 0/4] Introduce low-level debug for ARM architecture

Masahiro Yamada
2014-08-19T07:45:27Z

Hi York,

On Mon, 18 Aug 2014 19:14:07 -0700
York Sun <yorksun@freescale.com> wrote:

> On 08/16/2014 11:16 PM, Masahiro Yamada wrote:
> > I have been in trouble for a while to debug some nasty problem
> > where neighter a debugger nor printf() function is available.
> >
> > I found the lowlevel debug feature in ARM Linux can be used as is
> > in U-Boot too.
> >
> > I tested this series on our SoCs (32bit ARM, specificly Coretex-A9).
> > Because I was not sure about aarch64, I have this feature
> > depend on "! ARM64".
> >
> > 1/4 and 2/4 refactor a bit and move CONFIG_ARM64 to Kconfig.
> >
> > 3/4 imports some source files from Linux 3.16 and
> > 4/4 adds the Kconfig menu.
>
> Dear Masahiro,
>
> How do you use this debug facility? Do you print to memory?
>
> I don't know enough to comment on the patch. I don't see CP15 co-process in the
> SoC I am debugging.
>

At least one UART device must be available to use this facility.

The UART should be initialized (setup appropriate baudrate etc.)
in the early boot stage of U-Boot (= generally lowlevel_init() func)
or in another boot loader if U-Boot is loaded by it.

Best Regards
Masahiro Yamada