From: Leon Woestenberg <leon.woestenberg@gmail.com>
To: Leon Woestenberg <leon.woestenberg@gmail.com>,
linux-kernel@vger.kernel.org
Subject: Re: Memory-mapped I/O barriers, state of affairs?
Date: Mon, 22 Mar 2010 23:12:40 +0100 [thread overview]
Message-ID: <c384c5ea1003221512s229d1d94ta7690d109b75843a@mail.gmail.com> (raw)
In-Reply-To: <20100322201637.GA8476@bombe-desk.opditex>
Hello Andreas, all,
On Mon, Mar 22, 2010 at 9:16 PM, Andreas Bombe <aeb@debian.org> wrote:
> On Mon, Mar 22, 2010 at 08:18:49PM +0100, Leon Woestenberg wrote:
>> What is the current solution for that particular problem, i.e. how
>> should I make sure host memory writes are committed before I have an
>> external DMA device act on it?
>
> The dma_sync_* functions, if you reuse DMA buffers without unmapping,
> take care of that. Otherwise the process of mapping them handles it.
>
The mapping makes the memory cache-coherent. I already use that.
But does that mean that this coherency is guaranteed to occur before I
start MMIO access to a device, i.e. is there a guaranteed ordering
between the writes?
Regards,
--
Leon
next prev parent reply other threads:[~2010-03-22 22:12 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-22 19:18 Leon Woestenberg
2010-03-22 20:16 ` Andreas Bombe
2010-03-22 22:12 ` Leon Woestenberg [this message]
2010-03-23 0:14 ` Robert Hancock
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=c384c5ea1003221512s229d1d94ta7690d109b75843a@mail.gmail.com \
--to=leon.woestenberg@gmail.com \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®