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

From: Steve Chen
Date: Tue Sep 15 2009 - 12:24:10 EST


On Tue, 2009-09-15 at 15:41 +0200, Marek Vasut wrote:
> > -#if 0
> > +#if CONFIG_OLD_CPU_DELAY
>
> ifdef please
>
I assume this a vote in favor of considering this patch as an
alternative :) The updated patch is below. Since I'm only summarizing
the e-mail thread and put them into a patch (which is a less time
consuming process than continue reading and deleting e-mails on this
thread), contributors can add signed off before submitting to Russel.

Document #if 0 code block in delay.S and make it selectable for compile.

Signed-off-by: Steve Chen <schen@xxxxxxxxxx>

---

arch/arm/Kconfig | 8 ++++++++
arch/arm/lib/delay.S | 2 +-
2 files changed, 9 insertions(+), 1 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index aef63c8..ca8d535 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -813,6 +813,14 @@ 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 "Accurate delays for older CPU"
+ def_bool n
+ help
+ Enable if observing longer than expected delays and need more
+ accurate delays on older CPUs.
+
endmenu

source "arch/arm/common/Kconfig"
diff --git a/arch/arm/lib/delay.S b/arch/arm/lib/delay.S
index 8d6a876..67e679b 100644
--- a/arch/arm/lib/delay.S
+++ b/arch/arm/lib/delay.S
@@ -42,7 +42,7 @@ ENTRY(__const_udelay) @ 0 <= r0 <= 0x7fffff06
@ Delay routine
ENTRY(__delay)
subs r0, r0, #1
-#if 0
+#ifdef CONFIG_OLD_CPU_DELAY
movls pc, lr
subs r0, r0, #1
movls pc, lr


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