Dead Kconfig Option OMAP4_ERRATA_I688

Dead Kconfig Option OMAP4_ERRATA_I688

[Stefan Hengelein]

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During the research for my masters thesis i came across the
OMAP4_ERRATA_I688 option and realized, it is never possible to enable
this option.

The a62a6e98 commit added the "&& !ARCH_MULTIPLATFORM" dependency to
disable this option for multiplatforms. However, because of enclosing
dependencies, this option isn't available for non-MULTIPLATFORM
configurations either.

CONFIG_OMAP4_ERRATA_I688 is defined in the menu "TI OMAP/AM/DM/DRA
Family" which depends on ARCH_MULTI_V6 || ARCH_MULTI_V7. (in
arch/arm/mach-omap2/Kconfig)

ARCH_MULTI_V6 and ARCH_MULTI_V7 however are defined in the menu
"Multiple platform selection" which depends on ARCH_MULTIPLATFORM (in
arch/arm/Kconfig)

Which is a contradiction.

There are no selects on OMAP4_ERRATA_I688, which would ignore
dependencies, either.

The question is:
Was disabling this option for non-MULTIPLATFORM configurations also intentional?

i have added a minimal example of the problem.

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config MMU
	bool "MMU-based Paged Memory Management Support"
	default y

choice
	prompt "ARM system type"
	default ARCH_MULTIPLATFORM if MMU

config ARCH_MULTIPLATFORM
	bool "Allow multiple platforms to be selected"
	depends on MMU

endchoice

menu "Multiple platform selection"
	depends on ARCH_MULTIPLATFORM

comment "CPU Core family selection"

config ARCH_MULTI_V6
	bool "ARMv6 based platforms (ARM11)"

config ARCH_MULTI_V7
	bool "ARMv7 based platforms (Cortex-A, PJ4, Scorpion, Krait)"
	default y

endmenu


menu "TI OMAP/AM/DM/DRA Family"
	depends on ARCH_MULTI_V6 || ARCH_MULTI_V7

config SOC_OMAP5
	bool "TI OMAP5"
	depends on ARCH_MULTI_V7
	select ARCH_OMAP2PLUS

config ARCH_OMAP4
	bool "TI OMAP4"
	depends on ARCH_MULTI_V7
	select ARCH_OMAP2PLUS

config ARCH_OMAP2PLUS
	bool

if ARCH_OMAP2PLUS

config OMAP4_ERRATA_I688
	bool "OMAP4 errata: Async Bridge Corruption"
	depends on (ARCH_OMAP4 || SOC_OMAP5) && !ARCH_MULTIPLATFORM

endif

endmenu

Re: Dead Kconfig Option OMAP4_ERRATA_I688

[Tony Lindgren]

Hi,

Adding Santosh to Cc on this one.

* Stefan Hengelein <stefan.hengelein@fau.de> [150225 09:13]:
> During the research for my masters thesis i came across the
> OMAP4_ERRATA_I688 option and realized, it is never possible to enable
> this option.
> 
> The a62a6e98 commit added the "&& !ARCH_MULTIPLATFORM" dependency to
> disable this option for multiplatforms. However, because of enclosing
> dependencies, this option isn't available for non-MULTIPLATFORM
> configurations either.

Yes there is no clean way currently to enable this errata for
multiplatform.
 
> CONFIG_OMAP4_ERRATA_I688 is defined in the menu "TI OMAP/AM/DM/DRA
> Family" which depends on ARCH_MULTI_V6 || ARCH_MULTI_V7. (in
> arch/arm/mach-omap2/Kconfig)
> 
> ARCH_MULTI_V6 and ARCH_MULTI_V7 however are defined in the menu
> "Multiple platform selection" which depends on ARCH_MULTIPLATFORM (in
> arch/arm/Kconfig)
> 
> Which is a contradiction.
> 
> There are no selects on OMAP4_ERRATA_I688, which would ignore
> dependencies, either.
> 
> The question is:
> Was disabling this option for non-MULTIPLATFORM configurations also intentional?
> 
> i have added a minimal example of the problem.

>From what I remember the plan was to try to come up with a
multiplatform friendly way of doing this errata. Santosh,
any suggestions here? Should we just remove the code as it
seems nobody has complained about it for a few years now?

Regards,

Tony

Re: Dead Kconfig Option OMAP4_ERRATA_I688

[santosh shilimkar]

On 2/25/2015 9:14 AM, Tony Lindgren wrote:
> Hi,
>
> Adding Santosh to Cc on this one.
>
> * Stefan Hengelein <stefan.hengelein@fau.de> [150225 09:13]:
>> During the research for my masters thesis i came across the
>> OMAP4_ERRATA_I688 option and realized, it is never possible to enable
>> this option.
>>
>> The a62a6e98 commit added the "&& !ARCH_MULTIPLATFORM" dependency to
>> disable this option for multiplatforms. However, because of enclosing
>> dependencies, this option isn't available for non-MULTIPLATFORM
>> configurations either.
>
> Yes there is no clean way currently to enable this errata for
> multiplatform.
>
Right.To fix this, the barrier code needs to be run-time patched.

>> CONFIG_OMAP4_ERRATA_I688 is defined in the menu "TI OMAP/AM/DM/DRA
>> Family" which depends on ARCH_MULTI_V6 || ARCH_MULTI_V7. (in
>> arch/arm/mach-omap2/Kconfig)
>>
>> ARCH_MULTI_V6 and ARCH_MULTI_V7 however are defined in the menu
>> "Multiple platform selection" which depends on ARCH_MULTIPLATFORM (in
>> arch/arm/Kconfig)
>>
>> Which is a contradiction.
>>
>> There are no selects on OMAP4_ERRATA_I688, which would ignore
>> dependencies, either.
>>
>> The question is:
>> Was disabling this option for non-MULTIPLATFORM configurations also intentional?
>>
>> i have added a minimal example of the problem.
>
>  From what I remember the plan was to try to come up with a
> multiplatform friendly way of doing this errata. Santosh,
> any suggestions here? Should we just remove the code as it
> seems nobody has complained about it for a few years now?
>
I have to agree to with you on this.

Regards,
Santosh