[PATCH 1/3] ARM: debug: use kconfig choice for selecting DEBUG_LL UART

[Shawn Guo]

On Fri, Aug 19, 2011 at 12:08:22PM +0100, Will Deacon wrote:
> On Fri, Aug 19, 2011 at 05:59:57AM +0100, Shawn Guo wrote:
> > On Thu, Aug 18, 2011 at 05:07:12PM +0100, Will Deacon wrote:
> > > I'm not sure that sorting this list in alphabetical order is a good idea.
> > > This is a Kconfig choice, so the default value is the first one in the list
> > > that has its dependencies satisfied. Therefore, the ordering has a direct
> > > impact on the default UART selection.
> > > 
> > I'm unsure that the default UART selection makes much sense here.
> > When we build so many platforms into single image, it's hard to say
> > which one should be the default.  People anyway need to check if the
> > the UART selection matches the platform they are debugging on.
> 
> Ok, how about having the default choice as a dummy option which doesn't
> correspond to a UART?:
> 
To me, it is a little bit overkilled.  Can we just sort them in
alphabetical order and let the first one be the winner?  We can take
this as a reward to the good naming :)

> diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug
> index f23975a..455bc8c 100644
> --- a/arch/arm/Kconfig.debug
> +++ b/arch/arm/Kconfig.debug
> @@ -65,8 +65,12 @@ config DEBUG_USER
>  
>  # These options are only for real kernel hackers who want to get their hands dirty.
>  config DEBUG_LL
> +       bool
> +
> +config DEBUG_LL_UART
>         bool "Kernel low-level debugging functions"
>         depends on DEBUG_KERNEL
> +       select DEBUG_LL if !DEBUG_UART_NONE
>         help
>           Say Y here to include definitions of printascii, printch, printhex
>           in the kernel.  This is helpful if you are debugging code that
> @@ -74,7 +78,12 @@ config DEBUG_LL
>  
>  choice
>         prompt "Kernel low-level debugging port"
> -       depends on DEBUG_LL
> +       depends on DEBUG_LL_UART && (FOOTBRIDGE || ARCH_CLPS711X || \
> +                                    PLAT_SAMSUNG || ARCH_REALVIEW)

We will have to list a lot of ARCH/PLAT symbols here.  This is what
I meant overkilled actually.

Regards,
Shawn

> +       default DEBUG_UART_NONE
> +
> +       config DEBUG_UART_NONE
> +               bool "No UART selected (default)"
>  
>         config DEBUG_DC21285_PORT
>                 bool "Kernel low-level debugging messages via footbridge serial port"
> 
> 
> That way, you really have to select the UART for DEBUG_LL to be enabled.
> 
> > BTW, I just posted one patch for imx based on your series.  Are you
> > interested in folding it into yours?
> 
> Yep, I'll pick it up once Sascha is happy with it. If we go with the above,
> I'm happy to make the necessary changes.
>