Re: [PATCH 2/2] coresight: Adding coresight support to arm64

[Will Deacon <will.deacon@arm.com>]

On Fri, Jan 30, 2015 at 10:54:26PM +0000, mathieu.poirier@linaro.org wrote:
> From: Mathieu Poirier <mathieu.poirier@linaro.org>
> 
> Aside from tracers, all currently supported coresight IP blocks
> are 64 bit ready.  As such add the required symbol definition to
> compile the framework and drivers.
> 
> Also fixing a couple of warnings picked up by the 64bit compiler.
> 
> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> ---
>  arch/arm64/Kconfig.debug            | 48 +++++++++++++++++++++++++++++++++++++
>  drivers/coresight/coresight-etb10.c |  2 +-
>  drivers/coresight/coresight-tmc.c   |  2 +-
>  3 files changed, 50 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug
> index 5fdd6dce8061..77dfebbcbffe 100644
> --- a/arch/arm64/Kconfig.debug
> +++ b/arch/arm64/Kconfig.debug
> @@ -66,4 +66,52 @@ config DEBUG_SET_MODULE_RONX
>            against certain classes of kernel exploits.
>            If in doubt, say "N".
>  
> +menuconfig CORESIGHT
> +	bool "CoreSight Tracing Support"
> +	select ARM_AMBA
> +	help
> +	  This framework provides a kernel interface for the CoreSight debug
> +	  and trace drivers to register themselves with. It's intended to build
> +	  a topological view of the CoreSight components based on a DT
> +	  specification and configure the right serie of components when a
> +	  trace source gets enabled.

Why does this need to be duplicated by each architecture wanting to make
use of coresight capabilities defined under drivers/coresight? Can't we
instead have this menuconfig and associated suboptions defined by a core
Kconfig file, then have HAVE_ARCH_CORESIGHT_TRACE or something which can
be selected by architectures wanting to make use of the framework?

Will