[RFC PATCH 2/2] powerpc: Consolidate variants of real-mode MMIOs

[Michael Ellerman]

Benjamin Herrenschmidt <benh at kernel.crashing.org> writes:

> We have all sort of variants of MMIO accessors for the real mode
> instructions. This creates a clean set of accessors based on
> Linux normal naming conventions, replacing all occurrences of
> the old ones in the tree.
>
> I have purposefully removed the "out/in" variants in favor of
> only including __raw variants. Any code using these is already
> pretty much hand tuned to operate in a very specific environment.
> I've fixed up the 2 users (only one of them actually needed
> a barrier in the first place).

> diff --git a/arch/powerpc/include/asm/io.h b/arch/powerpc/include/asm/io.h
> index 5ed2924..45c136a 100644
> --- a/arch/powerpc/include/asm/io.h
> +++ b/arch/powerpc/include/asm/io.h
> @@ -417,15 +372,64 @@ static inline void __raw_writeq(unsigned long v, volatile void __iomem *addr)
>  }
>  
>  /*
> - * Real mode version of the above. stdcix is only supposed to be used
> - * in hypervisor real mode as per the architecture spec.
> + * Real mode versions of the above. Those instructions are only supposed
> + * to be used in hypervisor real mode as per the architecture spec.
>   */
> +static inline void __raw_rm_writeb(u8 val, volatile void __iomem *paddr)
> +{
> +	__asm__ __volatile__("stbcix %0,0,%1"
> +		: : "r" (val), "r" (paddr) : "memory");
> +}

I've never liked the "rm" naming. It makes me think rm -rf.

Can we just call them real_mode_writeb() and so on? Or add more
leading underscores to your taste.

cheers