From: Paul Brook <paul@codesourcery.com>
To: "Peter A. G. Crosthwaite" <peter.crosthwaite@petalogix.com>
Cc: peter.maydell@linaro.org, monstr@monstr.eu,
edgar.iglesias@petalogix.com, qemu-devel@nongnu.org,
John Linn <john.linn@xilinx.com>,
duyl@xilinx.com, linnj@xilinx.com, afaerber@suse.de,
john.williams@petalogix.com
Subject: Re: [Qemu-devel] [PATCH v3 2/4] cadence_ttc: initial version of device model
Date: Sat, 11 Feb 2012 14:18:49 +0000 [thread overview]
Message-ID: <201202111418.49949.paul@codesourcery.com> (raw)
In-Reply-To: <aa44a586a5d88ef2b3c9d66ff7062598d60bdf70.1328944806.git.peter.crosthwaite@petalogix.com>
> +static void cadence_timer_sync(CadenceTimerState *s)
> +{
>...
> + r = (int64_t)cadence_timer_get_steps(s, s->cpu_time - old_time);
> + x = (int64_t)s->reg_value + ((s->reg_count & COUNTER_CTRL_DEC) ? -r :
> r); +
> + for (i = 0; i < 3; ++i) {
> + if (is_between((int64_t)s->reg_match[i] << 16, s->reg_value, x)) {
> + s->reg_intr |= (2 << i);
> + }
> + }
By my reading this will miss events if they happen after the timer wraps.
e.g. for a count-up timer with reg_match==1 and the tick callback happens to
get delayed by 4 cycles, the timer may wrap straight to reg_value = 3.
Paul
next prev parent reply other threads:[~2012-02-11 14:18 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-11 7:35 [Qemu-devel] [PATCH v3 0/4] Zynq-7000 EPP platform model Peter A. G. Crosthwaite
2012-02-11 7:35 ` [Qemu-devel] [PATCH v3 1/4] cadence_uart: initial version of device model Peter A. G. Crosthwaite
2012-02-11 7:35 ` [Qemu-devel] [PATCH v3 2/4] cadence_ttc: " Peter A. G. Crosthwaite
2012-02-11 14:18 ` Paul Brook [this message]
2012-02-12 0:00 ` Peter Crosthwaite
2012-02-11 7:35 ` [Qemu-devel] [PATCH v3 3/4] cadence_gem: " Peter A. G. Crosthwaite
2012-02-11 7:35 ` [Qemu-devel] [PATCH v3 4/4] xilinx_zynq: machine model initial version Peter A. G. Crosthwaite
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=201202111418.49949.paul@codesourcery.com \
--to=paul@codesourcery.com \
--cc=afaerber@suse.de \
--cc=duyl@xilinx.com \
--cc=edgar.iglesias@petalogix.com \
--cc=john.linn@xilinx.com \
--cc=john.williams@petalogix.com \
--cc=linnj@xilinx.com \
--cc=monstr@monstr.eu \
--cc=peter.crosthwaite@petalogix.com \
--cc=peter.maydell@linaro.org \
--cc=qemu-devel@nongnu.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;
as well as URLs for NNTP newsgroup(s).