From: Arnd Bergmann <arnd@arndb.de>
To: "Russell King - ARM Linux" <linux@arm.linux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org, johnlinn@comcast.net,
nicolas pitre <nicolas.pitre@linaro.org>,
devicetree-discuss@lists.ozlabs.org,
linux-kernel@vger.kernel.org,
grant likely <grant.likely@secretlab.ca>,
john linn <john.linn@xilinx.com>
Subject: Re: [RFC PATCH 4/4] ARM: Xilinx: Adding Xilinx board support
Date: Tue, 3 May 2011 12:35:41 +0200 [thread overview]
Message-ID: <201105031235.41888.arnd@arndb.de> (raw)
In-Reply-To: <20110503085220.GL28001@n2100.arm.linux.org.uk>
On Tuesday 03 May 2011, Russell King - ARM Linux wrote:
> On Tue, May 03, 2011 at 09:58:14AM +0200, Arnd Bergmann wrote:
> > On Tuesday 03 May 2011 01:01:18 Russell King - ARM Linux wrote:
> > > It is preferable to use the same mapping, as it ensures that you're not
> > > going to create incompatible aliases.
> >
> > Is aliasing a problem for MMIO mappings? I would think that you can
> > ioremap registers anywhere and as often as you want because they are
> > never cacheable.
>
> Provided the type and sharability is identical then there is no problem.
> I wasn't referring to multiple ioremap()s of the same region - that
> should be fine as the same attributes will be used. If you mix ioremap()
> and iotable_init() then you _could_ have problems if you don't use
> MT_DEVICE in the iotable.
>
> What I'm basically saying is that mixing the methods of creating these
> mappings makes it much easier to get tripped up over these issues.
Ok, makes sense.
Thanks,
Arnd
next prev parent reply other threads:[~2011-05-03 10:36 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <90477150.2231869.1304372815517.JavaMail.root@sz0140a.emeryville.ca.mail.comcast.net>
2011-05-02 21:50 ` [RFC PATCH 4/4] ARM: Xilinx: Adding Xilinx board support johnlinn
2011-05-02 23:01 ` Russell King - ARM Linux
2011-05-02 23:36 ` Grant Likely
2011-05-03 7:58 ` Arnd Bergmann
2011-05-03 8:52 ` Russell King - ARM Linux
2011-05-03 10:35 ` Arnd Bergmann [this message]
[not found] <1518608384.2203937.1304349657551.JavaMail.root@sz0140a.emeryville.ca.mail.comcast.net>
2011-05-02 21:27 ` johnlinn
2011-05-02 21:36 ` Arnd Bergmann
2011-05-02 5:07 [RFC PATCH 0/4] ARM: Basic Xilinx Support Grant Likely
2011-05-02 5:08 ` [RFC PATCH 4/4] ARM: Xilinx: Adding Xilinx board support Grant Likely
2011-05-02 7:06 ` Michal Simek
2011-05-02 8:39 ` Arnd Bergmann
2011-05-02 13:29 ` Rob Herring
2011-05-02 15:52 ` Arnd Bergmann
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