Message-ID: <1352474951.1814.40.camel@sauron.fi.intel.com>
Subject: Re: [PATCH] dma: add new DMA control commands
From: Artem Bityutskiy <dedekind1@gmail.com>
Reply-To: dedekind1@gmail.com
To: Huang Shijie <b32955@freescale.com>
Cc: Marek Vasut <marex@denx.de>, Vinod Koul <vinod.koul@linux.intel.com>,
        djbw@fb.com, khali@linux-fr.org, ben-linux@fluff.org,
        w.sang@pengutronix.de, cjb@laptop.org, dwmw2@infradead.org, lrg@ti.com,
        broonie@opensource.wolfsonmicro.com, perex@perex.cz, tiwai@suse.de,
        shawn.guo@linaro.org, linux-kernel@vger.kernel.org,
        linux-i2c@vger.kernel.org, linux-mmc@vger.kernel.org,
        linux-mtd@lists.infradead.org, alsa-devel@alsa-project.org,
        linux-arm-kernel@lists.infradead.org, linux@arm.linux.org.uk,
        Huang Shijie <shijie8@gmail.com>,
        Fabio Estevam <fabio.estevam@freescale.com>
Date: Fri, 09 Nov 2012 17:29:11 +0200
In-Reply-To: <507FBDF1.5050602@freescale.com>
References: <1350538335-29026-1-git-send-email-b32955@freescale.com>
	 <201210180914.58527.marex@denx.de> <507FB495.7050104@freescale.com>
	 <201210181016.06782.marex@denx.de> <507FBDF1.5050602@freescale.com>
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On Thu, 2012-10-18 at 16:29 +0800, Huang Shijie wrote:
> =E4=BA=8E 2012=E5=B9=B410=E6=9C=8818=E6=97=A5 16:16, Marek Vasut =E5=86=
=99=E9=81=93:
> > So we can't stream data from the chip? About time to adjust the MTD fra=
mework to
> > allow that. Maybe implement a command queue?
> >
>=20
> to Artem & David:
>     is this possible to stream the data out with a command queue?

Well, I think there was no HW which supported reading multiple pages
with DMA before, are your sure yours support this? Usually reading a
NAND page consists of 2 phases - loading the NAND array contents to a
controller buffer, and then copying that to RAM. And the second part is
something people sometimes do with DMA, AFAIU.

If your HW supports this, sure the MTD framework can be re-worked. Or
you may write your own 'mtd->_read()' / 'mtd->_write()' implementation.

--=20
Best Regards,
Artem Bityutskiy

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