From: Mike Frysinger <vapier@gentoo.org>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH V3] net: fec_mxc: allow use with cache enabled
Date: Tue, 13 Mar 2012 16:14:54 -0400 [thread overview]
Message-ID: <201203131614.55654.vapier@gentoo.org> (raw)
In-Reply-To: <4F5F9515.1090300@boundarydevices.com>
On Tuesday 13 March 2012 14:42:29 Eric Nelson wrote:
> On 03/13/2012 07:41 AM, Mike Frysinger wrote:
> > On Tuesday 13 March 2012 10:04:31 Eric Nelson wrote:
> >> --- a/drivers/net/fec_mxc.c
> >> +++ b/drivers/net/fec_mxc.c
> >>
> >> +#if ARCH_DMA_MINALIGN> CONFIG_SYS_CACHELINE_SIZE
> >> +#define CONFIG_FEC_ALIGN ARCH_DMA_MINALIGN
> >> +#else
> >> +#define CONFIG_FEC_ALIGN CONFIG_SYS_CACHELINE_SIZE
> >> +#endif
> >
> > i don't think this is something you should be checking. if this is an
> > actual problem (and i don't think it is), it's something we should
> > handle in common code. if you need to dma from memory, then use
> > ARCH_DMA_MINALIGN.
>
> Marek, you've mentioned some restrictions for other i.MX devices.
>
> Are you aware of any problem collapsing this?
>
> Note that other CPUs will need to have CONFIG_SYS_CACHELINE_SIZE to
> prevent the default of 64.
and those cores should be making sure that ARCH_DMA_MINALIGN is sufficient to
handle those larger cache lines. this define provides two meanings: minimum
alignment for the DMA itself, and for sanely flushing the cache on that dma
buffer. so there should be no situation where ARCH_DMA_MINALIGN is smaller
than the cacheline size.
the few boards i see defining CONFIG_SYS_CACHELINE_SIZE to 64 are all ARM
based, and ARM sets ARCH_DMA_MINALIGN to CONFIG_SYS_CACHELINE_SIZE if it's
defined
-mike
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next prev parent reply other threads:[~2012-03-13 20:14 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <http://lists.denx.de/pipermail/u-boot/2012-March/#119442>
2012-03-13 14:04 ` [U-Boot] [PATCH V3] net: fec_mxc: allow use with cache enabled Eric Nelson
2012-03-13 14:41 ` Mike Frysinger
2012-03-13 18:42 ` Eric Nelson
2012-03-13 20:14 ` Mike Frysinger [this message]
2012-03-14 1:43 ` Marek Vasut
2012-03-14 5:12 ` Eric Nelson
2012-03-14 5:41 ` Mike Frysinger
2012-03-14 19:12 ` Eric Nelson
2012-03-14 20:33 ` Mike Frysinger
2012-03-14 21:04 ` Eric Nelson
2012-03-14 21:15 ` Mike Frysinger
2012-03-14 5:45 ` Marek Vasut
2012-03-14 1:42 ` Marek Vasut
2012-03-13 15:48 ` Eric Nelson
2012-03-14 1:44 ` Marek Vasut
2012-03-14 1:46 ` Marek Vasut
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