Re: [PATCH 2/9] mmc: tmio: tmio_mmc_host has .dma

Kuninori Morimoto
2015-01-08T01:57:05Z

Hi Arnd

> > > dmaengine: shdma: use normal interface for passing slave id
> > >
> > > The shmobile platform is one of only two users of the slave_id field
> > > in dma_slave_config, which is incompatible with the way that the
> > > dmaengine API normally works.
> > >
> > > I've had a closer look at the existing code now and found that all
> > > slave drivers that pass a slave_id in dma_slave_config for SH do that
> > > right after passing the same ID into shdma_chan_filter, so we can just
> > > rely on that. However, the various shdma drivers currently do not
> > > remember the slave ID that was passed into the filter function when
> > > used in non-DT mode and only check the value to find a matching channel,
> > > unlike all other drivers.
> > >
> > > There might still be drivers that are not part of the kernel that rely
> > > on setting the slave_id to some other value, so to be on the safe side,
> > > this adds another 'real_slave_id' field to shdma_chan that remembers
> > > the ID and uses it when a driver passes a zero slave_id in dma_slave_config,
> > > like most drivers do.
> > >
> > > Eventually, the real_slave_id and slave_id fields should just get merged
> > > into one field, but that requires other changes.
> > >
> > > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > > ----
(snip)
> I was actually hoping that you could pick up my patch and send it as a
> follow-up to your series once you have a working version. As I mentioned,
> the driver changes to remove the slave_id assignment can be done either
> together with the base patch or as a follow-up.

OK, I can do it if you want :)

Best regards
---
Kuninori Morimoto