[PATCH v3] arm: remove unused code in delay.S

[Uwe Kleine-König]

Hello Steve,

On Fri, Sep 18, 2009 at 11:46:58AM -0500, Steve Chen wrote:
> Document #if 0 code block in delay.S and make it selectable for compile.
> 
> Signed-off-by: Steve Chen <schen at mvista.com>
> 
> ---
>  arch/arm/Kconfig     |   31 +++++++++++++++++++++++++++++++
>  arch/arm/lib/delay.S |    2 +-
>  2 files changed, 32 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index aef63c8..f44cb70 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -813,6 +813,37 @@ config ARM_ERRATA_460075
>  	  ACTLR register. Note that setting specific bits in the ACTLR
> register
>  	  may not be available in non-secure mode.
>  
> +config OLD_CPU_DELAY
> +	depends on CPU_32v3 || CPU_32v4 || CPU_32v4T
> +	bool "Different delay() code for some older CPUs"
> +	def_bool n
as already noted, n is the default (that would better be expressed using
"default n" btw).

> +	help
> +	  Enable this if observing longer than expected delays.  This code
> +	  improves delay accuracy for some CPUs.  However, it can also cause
> +	  delay duration to be too short for others which leads to stability
> +	  issues.
> +
> +	  In other words, do not enable unless you can guarantee that the
> +	  processor (or ALL of the processors if building a generic kernel)
> +	  delays for at least the time requested after enabling.
> +
> +	  ARM610 and ARM710 are known to benefit from enabling this option.
> +	  It should not be enabled for StrongARMs, because it is known
> +	  to produce too short delays on those.
> +
> +	  Lastly, below are 2 lists.  The first list contains the processors
> +	  that would benefit from enabling this flag, and the second list
> +	  contains processor that are known to have issues.  Please note that
> +	  both lists are by no means complete.  Entries are expected to be
> +	  added and refined.  If you like to update the list, please send a
> +	  patch to Linux ARM mailing list.
I'd delete the last three sentences.

> +	  CPUs should enable this flag
> +		ARM610
> +		ARM710
> +
> +	  CPUs should disable this flag
> +		StrongARM
everything armv5+ ?

Best regards
Uwe

-- 
Pengutronix e.K.                              | Uwe Kleine-König            |
Industrial Linux Solutions                    | http://www.pengutronix.de/  |