Messages in this thread Patch in this message | | | Subject | [PATCH v2] arm: remove unused code in delay.S | From | Steve Chen <> | Date | Thu, 17 Sep 2009 16:29:38 -0500 |
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Document #if 0 code block in delay.S and make it selectable for compile.
Signed-off-by: Steve Chen <schen@mvista.com>
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arch/arm/Kconfig | 14 ++++++++++++++ arch/arm/lib/delay.S | 2 +- 2 files changed, 15 insertions(+), 1 deletions(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index aef63c8..ed8bf14 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -813,6 +813,20 @@ 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 + 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. + 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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