Messages in this thread | | | From | Kuninori Morimoto <> | Subject | Re: [PATCH] dmaengine: rcar-dmac: read DMATCRB instead of DMATCR for residue | Date | Mon, 16 Oct 2017 07:12:22 +0000 |
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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@renesas.com> > > [Kuninori: added detail information in log] > > Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> (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
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