Re: [PATCH] dmaengine: rcar-dmac: read DMATCRB instead of DMATCR for residue

[Kuninori Morimoto]

Hi Geert

> > SYS/RT/Audio DMAC have both TCR/TCRB register.
> > Its difference is transfer counter value of read (= TCR)
> > or write (= TCRB). The relationship is like below.
> >
> >          TCR       TCRB
> >  [SOURCE] -> [DMAC] -> [DESTINATION]
> >
> > Thus, we want to read TCRB instead of TCR for residue.
> > Otherwise, Sound Capture has noise after PluseAudio support
> > (= 07b7acb51d2 ("ASoC: rsnd: update pointer more accurate"))
> >
> > Signed-off-by: Hiroyuki Yokoyama <hiroyuki.yokoyama.vx@xxxxxxxxxxx>
> > [Kuninori: added detail information in log]
> > Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>
(snip)
> However, shouldn't the register to use depend on the DMA direction?

I think TCRB is OK for all direction,
but yes, we can care its direction.
I can post v2 patch, if you want.
Geert do you want to care direction ?

Best regards
---
Kuninori Morimoto