MMIO and gcc re-ordering issue
haavard.skinnemoen at atmel.com
Wed May 28 18:36:48 EST 2008
Benjamin Herrenschmidt <benh at kernel.crashing.org> wrote:
> > > I'm happy to say that __raw is purely about ordering and make them
> > > byteswap on powerpc tho (ie, make them little endian like the non-raw
> > > counterpart).
> > That would break a lot of drivers.
> How many actually use __raw_ * ?
I do -- in all the drivers for on-chip peripherals that are shared
between AT91 ARM (LE) and AVR32 (BE). Since everything goes on inside
the chip, we must use LE accesses on ARM and BE accesses on AVR32.
Currently, this is the only interface I know that can do native-endian
accesses, so if you take it away, I'm gonna need an alternative
interface that doesn't do byteswapping.
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