Hi Daniel, On Tue, Sep 09, 2014 at 01:12:40PM +0100, Daniel Thompson wrote: > Currently the read[bwlq]_relaxed() family are implemented on every > architecture except blackfin, m68k[1], metag, openrisc, s390[2] and > score. Increasingly drivers are being optimized to exploit relaxed > reads putting these architectures at risk of compilation failures for > shared drivers. > > This patch addresses this by providing implementations of > read[bwlq]_relaxed() that are identical to the equivalent read[bwlq](). > All the above architectures include asm-generic/io.h . > > Note that currently only eight architectures (alpha, arm, arm64, avr32, > hexagon, microblaze, mips and sh) implement write[bwlq]_relaxed() meaning > these functions are deliberately not included in this patch. > > [1] m68k includes the relaxed family only when configured *without* MMU. > [2] s390 requires CONFIG_PCI to include the relaxed family. > > Signed-off-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx> > Cc: Will Deacon <will.deacon@xxxxxxx> > Cc: Arnd Bergmann <arnd@xxxxxxxx> > Cc: linux-arch@xxxxxxxxxxxxxxx > --- > include/asm-generic/io.h | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) I have a larger series adding these (and the write equivalents) to all architectures that I periodically post and then fail to get on top of. The key part you're missing is defining some generic semantics for these accessors. Without those, I don't think it makes sense to put them into asm-generic, because drivers can't safely infer any meaning from the relaxed definition. Ben and I agreed on something back in May: https://lkml.org/lkml/2014/5/22/468 but I need to send a new version including: - ioreadX_relaxed and iowriteX_relaxed - Strengthening non-relaxed I/O accessors on architectures with non-empty mmiowb() I'll bump it up the list. In the meantime, you can have a look at my io branch on kernel.org Will -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
