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Date:   Fri, 23 Nov 2018 20:52:15 +0200
From:   Aaro Koskinen <aaro.koskinen@iki.fi>
To:     Peter Ujfalusi <peter.ujfalusi@ti.com>
Cc:     Russell King - ARM Linux <linux@armlinux.org.uk>, vkoul@kernel.org,
        dan.j.williams@intel.com, dmaengine@vger.kernel.org,
        linux-kernel@vger.kernel.org, tony@atomide.com,
        linux-omap@vger.kernel.org
Subject: Re: [PATCH] dmaengine: ti: omap-dma: Configure LCH_TYPE for OMAP1
Message-ID: <20181123185215.GH12912@darkstar.musicnaut.iki.fi>
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Hi,

On Fri, Nov 23, 2018 at 02:35:04PM +0200, Peter Ujfalusi wrote:
> On 22/11/2018 17.12, Russell King - ARM Linux wrote:
> > I'm also not sure about this:
> > 
> >         if (cpu_is_omap15xx())
> >                 end++;
> > 
> > in dma_dest_len() - is that missing from the omap-dma driver?  It looks
> > like a work-around for some problem on OMAP15xx, but I can't make sense
> > about why it's in the UDC driver rather than the legacy DMA driver.
> 
> afaik no other legacy drivers were doing similar thing, this must be
> something which is needed for the omap_udc driver to fix up something?

Here's the patch that added it: https://marc.info/?l=linux-omap&m=119634396324221&w=2

"Make DMA-OUT behave on the 1510 ... the 1510 CPC register was just
off-by-one with respect to the 1611 CDAC"

A.