[PATCH v3] arm: remove unused code in delay.S
u.kleine-koenig at pengutronix.de
Fri Sep 18 15:09:20 EDT 2009
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
> 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+ ?
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