[PATCH] ARM: optimize memset_io()/memcpy_fromio()/memcpy_toio()

[Dirk Behme]

Hi Arnd,

On 13.06.2013 19:13, Russell King - ARM Linux wrote:
> On Thu, Jun 13, 2013 at 02:47:35PM +0200, Arnd Bergmann wrote:
>> On Thursday 13 June 2013 12:05:02 Russell King - ARM Linux wrote:
>>> Yes, unfortunately it should be selectable by platform, though it needs
>>> to be done carefully.  Some ARM platforms can't cope with full 32-bit
>>> accesses to MMIO.
>>>
>>> I don't think any of those intersect with the single zImage project, so
>>> those should be fine to have it always enabled - it's only the older
>>> platforms that might have issues.
>>
>> Are those all StrongARM and XScale based platforms? If so, I definitely
>> don't expect them to go multiplatform.
>
> I'm not 100% positive on that, but...
>
>> Can we combine this with the existing CONFIG_NEED_MACH_IO_H?
>
> I think we probably can - because that implies that the generic set of
> IO accessors are already being used, which means 8, 16 and 32 bit
> accesses must be supportable without any kind of trickery.

Do you like to send a patch with this CONFIG_NEED_MACH_IO_H proposal?

Many thanks and best regards

Dirk

P.S.: Just for reference, the initial patch from Russell we are 
talking about:

http://permalink.gmane.org/gmane.linux.ports.arm.kernel/190902