[U-Boot] [PATCH v5 01/23] ppc: Add initial memory barrier macros

[Scott Wood <scottwood@freescale.com>]

On 02/08/2013 09:11:57 AM, Simon Glass wrote:
> These are available on other architectures, so add them on ppc.
> 
> Signed-off-by: Simon Glass <sjg@chromium.org>
> ---
> Changes in v5: None
> Changes in v4: None
> Changes in v3: None
> Changes in v2: None
> 
>  arch/powerpc/include/asm/io.h | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/arch/powerpc/include/asm/io.h  
> b/arch/powerpc/include/asm/io.h
> index 1f12c29..1bf12f5 100644
> --- a/arch/powerpc/include/asm/io.h
> +++ b/arch/powerpc/include/asm/io.h
> @@ -317,4 +317,12 @@ static inline phys_addr_t virt_to_phys(void *  
> vaddr)
>  #endif
>  }
> 
> +/*
> + * TODO: The kernel offers some more advanced versions of barriers,  
> it might
> + * have some advantages to use them instead of the simple one here.
> + */
> +#define dmb()		__asm__ __volatile__ ("" : : : "memory")
> +#define __iormb()	dmb()
> +#define __iowmb()	dmb()

What is the definition of these?  Given that we already have an  
architecture-independent barrier(), I assume this is meant to be an  
actual hardware barrier rather than a compiler barrier, so this is not  
a correct implementation.

-Scott