Re: [PATCH v4 1/5] ARM: omap4: Provide do_wfi() for Thumb-2

Nicolas Pitre
2011-02-09T16:19:45Z

On Wed, 9 Feb 2011, Dave Martin wrote:

> For CONFIG_THUMB2_KERNEL, the existing definition of do_wfi() will
> insert invalid code into the instruction stream.
>
> Any assembler which can assemble Thumb-2 is guaranteed to accept
> the "wfi" mnemonic, so for the Thumb-2 case, just use the mnemonic.
>
> The ARM case is left as-is.
>
> Signed-off-by: Dave Martin <dave.martin@linaro.org>
> ---
> arch/arm/mach-omap2/include/mach/omap4-common.h | 4 ++++
> 1 files changed, 4 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/include/mach/omap4-common.h b/arch/arm/mach-omap2/include/mach/omap4-common.h
> index 5b0270b..de441c0 100644
> --- a/arch/arm/mach-omap2/include/mach/omap4-common.h
> +++ b/arch/arm/mach-omap2/include/mach/omap4-common.h
> @@ -17,8 +17,12 @@
> * wfi used in low power code. Directly opcode is used instead
> * of instruction to avoid mulit-omap build break

Might be a good idea to fix the typo above while at it.

> +#ifdef CONFIG_THUMB2_KERNEL
> +#define do_wfi() __asm__ __volatile__ ("wfi" : : : "memory")
> +#else
> #define do_wfi() \
> __asm__ __volatile__ (".word 0xe320f003" : : : "memory")
> +#endif
>
> #ifdef CONFIG_CACHE_L2X0
> extern void __iomem *l2cache_base;
> --
> 1.7.1
>