From: Roland Dreier <rdreier@cisco.com>
To: David Miller <davem@davemloft.net>
Cc: Eric.Moore@lsi.com, linux-scsi@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: HELP: Is writeq an atomic operation??
Date: Fri, 02 May 2008 15:43:32 -0700 [thread overview]
Message-ID: <adaabj8499n.fsf@cisco.com> (raw)
In-Reply-To: <20080502.153210.122414532.davem@davemloft.net> (David Miller's message of "Fri, 02 May 2008 15:32:10 -0700 (PDT)")
> > Is a 64bit write to MMIO registers an atomic operation when using the
> > writeq API?
>
> The answer to this question this is platform dependent.
>
> On most 64-bit platforms, it is. On some 32-bit ones, it is not.
Are there any 32-bit platforms with writeq()? A quick grep suggests not.
Are there any 64-bit platforms where writeq() allows the MMIO to be
split into multiple cycles from the target device's view? I've been
coding assuming that at least no other MMIO writes will reach the device
in the middle of a writeq().
- R.
next prev parent reply other threads:[~2008-05-02 22:43 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-02 22:19 HELP: Is writeq an atomic operation?? Moore, Eric
2008-05-02 22:32 ` David Miller
2008-05-02 22:43 ` Roland Dreier [this message]
2008-05-02 22:49 ` David Miller
2008-05-02 22:49 ` Moore, Eric
2008-05-02 22:53 ` Roland Dreier
2008-05-02 23:13 ` Moore, Eric
2008-05-02 23:21 ` Roland Dreier
2008-05-02 23:31 ` Moore, Eric
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=adaabj8499n.fsf@cisco.com \
--to=rdreier@cisco.com \
--cc=Eric.Moore@lsi.com \
--cc=davem@davemloft.net \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-scsi@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