Re: [PATCH 2/2] dma: mv_xor: Use high_base mmio where appropriate

From: Ezequiel Garcia
Date: Tue Oct 29 2013 - 04:34:18 EST


On Mon, Oct 28, 2013 at 04:47:20PM -0700, Dan Williams wrote:
> [ adding dmaengine ]
>
> On Mon, Oct 28, 2013 at 3:54 PM, Ezequiel Garcia
> <ezequiel.garcia@xxxxxxxxxxxxxxxxxx> wrote:
> > Despite requesting two memory resources, called 'base' and 'high_base', the
> > driver uses explicitly only the former. The latter is being used implicitly
> > by addressing at offset +0x200, which in practice accesses high_base.
> >
> > Instead of relying in such trick, let's define the registers with the
> > offset from high_base, and use high_base explicitly where appropriate.
> >
> > Signed-off-by: Ezequiel Garcia <ezequiel.garcia@xxxxxxxxxxxxxxxxxx>
> > ---
> > drivers/dma/mv_xor.c | 3 ++-
> > drivers/dma/mv_xor.h | 25 +++++++++++++------------
> > 2 files changed, 15 insertions(+), 13 deletions(-)
>
> Since it's unused I'd prefer a patch that just deletes xor_high_base.
>

It's wrongly *unused*, the mmio high_base is actually being used
implicitly by always addressing at an offset that addresses +200.

Deleting high_base would actually make it worse, for that region
will no longer be ioremaped. Maybe the commit message is not clear
about it?
--
Ezequiel GarcÃa, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com
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