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Date:   Wed, 21 Oct 2020 17:03:48 +0200
From:   Maxime Ripard <maxime@cerno.tech>
To:     Chen-Yu Tsai <wens@csie.org>
Cc:     Alexander Kochetkov <al.kochet@gmail.com>,
        Mark Brown <broonie@kernel.org>, linux-spi@vger.kernel.org,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] spi: spi-sun6i: implement DMA-based transfer mode
Message-ID: <20201021150348.g2anzbqalhrmypdl@gilmour.lan>
References: <20201015154740.20825-1-al.kochet@gmail.com>
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On Tue, Oct 20, 2020 at 11:52:34AM +0800, Chen-Yu Tsai wrote:
> On Tue, Oct 20, 2020 at 1:43 AM Alexander Kochetkov <al.kochet@gmail.com>=
 wrote:
> >
> >
> >
> > > 19 =D0=BE=D0=BA=D1=82. 2020 =D0=B3., =D0=B2 11:21, Maxime Ripard <max=
ime@cerno.tech> =D0=BD=D0=B0=D0=BF=D0=B8=D1=81=D0=B0=D0=BB(=D0=B0):
> > >
> > > Hi!
> > >
> > > On Thu, Oct 15, 2020 at 06:47:40PM +0300, Alexander Kochetkov wrote:
> > >> DMA-based transfer will be enabled if data length is larger than FIF=
O size
> > >> (64 bytes for A64). This greatly reduce number of interrupts for
> > >> transferring data.
> > >>
> > >> For smaller data size PIO mode will be used. In PIO mode whole buffe=
r will
> > >> be loaded into FIFO.
> > >>
> > >> If driver failed to request DMA channels then it fallback for PIO mo=
de.
> > >>
> > >> Tested on SOPINE (https://www.pine64.org/sopine/)
> > >>
> > >> Signed-off-by: Alexander Kochetkov <al.kochet@gmail.com>
> > >
> > > Thanks for working on this, it's been a bit overdue
> >
> > Hi, Maxime!
> >
> > We did custom A64 based computation module for our product.
> > Do you mean that A64 is obsolete or EOL product?
> > If so, can you recommend active replacement for A64 from Allwinner same=
 price?
>=20
> I believe what Maxime meant was that DMA transfer for SPI is a long
> sought-after feature, but no one had finished it.

Yeah, that's what I meant :)

Maxime

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