[PATCH 2/3] arm: caches: add DCACHE_DEFAULT_OPTION

[Patrick DELAUNAY]

Dear Marek,

> Sent: jeudi 9 avril 2020 12:21
> To: Patrick DELAUNAY <patrick.delaunay at st.com>; u-boot at lists.denx.de
> 
> On 4/9/20 12:01 PM, Patrick DELAUNAY wrote:
> > Dear Marek,
> 
> Hi,
> 
> >> From: Uboot-stm32 <uboot-stm32-bounces at st-md-mailman.stormreply.com>
> >> On Behalf Of Patrick DELAUNAY
> >>
> >> Dear Marek,
> >>
> >>> From: Marek Vasut <marex at denx.de>
> >>> Sent: vendredi 3 avril 2020 23:29
> >>>
> >>> On 4/3/20 10:28 AM, Patrick Delaunay wrote:
> >>>> Add the new flags DCACHE_DEFAULT_OPTION to define the default
> >>>> option to use according the compilation flags
> >>>> CONFIG_SYS_ARM_CACHE_WRITETHROUGH or
> >>> CONFIG_SYS_ARM_CACHE_WRITEALLOC.
> >>>
> >>> Can't you unify these macros into a single Kconfig "select"
> >>> statement instead , and then just select the matching cache configuration in
> Kconfig ?
> >>
> >> Yes I will try, with 2 steps
> >> - migrate existing CONFIG_SYS_ARM_CACHE_.... in Kconfig
> >
> > First step done...
> > I will push it as a separate patchset I think.
> >
> >> - add new option CONFIG_SYS_ARM_CACHE_OPTION
> >
> > In fact it is to difficult to use select because each defines
> > DCACHE_XXX value can have several values
> >
> > they are build according CONFIG_ARM64 / LPAE
> >
> > But, I can't use this define in Kconfig
> >
> > I try :
> > option	ARM_OPTION
> > 	int "option"
> > 	default DCACHE_WRITETHROUGHT if
> CONFIG_SYS_ARM_CACHE_WRITETHROUGH
> > 	default DCACHE_ WRITEALLOC if CONFIG_SYS_ARM_CACHE_
> WRITEALLOC
> > 	default DCACHE_WRITEBACK if
> CONFIG_SYS_ARM_CACHE_WRITEBACK
> >
> > int and hex is invalid, and string can't be use with "".
> >
> > And I don't found way to build it automatically when option is activated.
> >
> > Any idea ?
> 
> Maybe you can have a select in the Kconfig to set some differently named option,
> e.g.
> 
> DCACHE_MODE_WRITE{THROUGH,ALLOC,BACK}
> 
> and then an ifdef in some header file, e.g.
> 
> #ifdef CONFIG_DCACHE_MODE_WRITETHROUGH
> #define ARM_CACHE_MODE DCACHE_WRITETHROUGH ...
> 
> And then use ARM_CACHE_MODE where you need a value and
> CONFIG_DCACHE_MODE{...} where you need a config option check.
> 
> Does this work ?

I try with string and default (as select is allowed on for bolean or trisate),
And I failed :-<

I don't found a way to have the de-stringficate the KConfig option
to generated the correct define

config SYS_ARM_CACHE_POLICY
	string "Name of the ARM data write cache policy"
	default WRITEBACK if SYS_ARM_CACHE_WRITEBACK
	default WRITETHROUGH if SYS_ARM_CACHE_WRITEBACK
	default WRITEALLOC if SYS_ARM_CACHE_WRITEALLOC

#define DCACHE_DEFAULT_OPTION	DCACHE_ ## CONFIG_SYS_ARM_CACHE_POLICY

=> error: ‘DCACHE_CONFIG_SYS_ARM_CACHE_POLICY’ undeclared (first use in this function); did you mean ‘CONFIG_SYS_ARM_CACHE_POLICY’?

#define DCACHE_OPTION(s)	DCACHE_ ## CONFIG_SYS_ARM_CACHE_POLICY

#define DCACHE_DEFAULT_OPTION	DCACHE_OPTION(CONFIG_SYS_ARM_CACHE_POLICY)

arch/arm/include/asm/system.h:488:26: error: ‘DCACHE_’ undeclared (first use in this function); did you mean ‘DCACHE_OFF’?
arch/arm/lib/cache-cp15.c:99:25: error: expected ‘)’ before string constant

The stringification is possible but not the inverse operation (remove the quote)...

In my .config, CONFIG_SYS_ARM_CACHE_POLICY="WRITEBACK"

Regards

Patrick