From: Guenter Roeck <linux@roeck-us.net>
To: Matthew McClintock <mmcclint@codeaurora.org>
Cc: Stephen Boyd <sboyd@codeaurora.org>,
andy.gross@linaro.org, linux-arm-msm@vger.kernel.org,
qca-upstream.external@qca.qualcomm.com,
Wim Van Sebroeck <wim@iguana.be>,
"open list:WATCHDOG DEVICE DRIVERS"
<linux-watchdog@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 08/17] watchdog: qcom: configure BARK time in addition to BITE time
Date: Thu, 24 Mar 2016 09:17:54 -0700 [thread overview]
Message-ID: <20160324161754.GA6515@roeck-us.net> (raw)
In-Reply-To: <19DAEEE1-1019-49FB-A921-4311F592A7EC@codeaurora.org>
On Thu, Mar 24, 2016 at 10:46:42AM -0500, Matthew McClintock wrote:
> On Mar 23, 2016, at 5:42 PM, Stephen Boyd <sboyd@codeaurora.org> wrote:
> >
> > On 03/23, Matthew McClintock wrote:
> >> For certain parts and some versions of TZ, TZ will reset the chip
> >> when a BARK is triggered even though it was not configured here. So
> >> by default let's configure this BARK time as well.
> >>
> >
> > Why isn't TZ configuring the bark time to what it wants? I'm lost
> > why we have to do this for them.
>
> So it was done like this to ensure we had a valid upgrade. The bootloader is using the watchdog to ensure the system is bootable and if not it will revert back to the working images.
>
> Bottom line is, for some versions of TZ out there, if we enable watchdog coming out of boot the bark time is already configured by the boot loader and TZ is configured to intercept this interrupt and do some register saving (for crashdump) and we end up getting a watchdog reset during boot.
>
> It’s even a little more complex, because in order for the TZ to save the registers you need to pad the BITE time a bit higher than the BARK time, but I was leaving that for another day.
>
Sounds like an op[timal target for using pretimeout ?
Guenter
next prev parent reply other threads:[~2016-03-24 16:17 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1458770712-10880-1-git-send-email-mmcclint@codeaurora.org>
2016-03-23 22:05 ` [PATCH 06/17] watchdog: qcom: update device tree bindings Matthew McClintock
2016-03-23 22:26 ` Stephen Boyd
2016-03-24 15:49 ` Matthew McClintock
2016-03-25 14:13 ` Rob Herring
2016-03-23 22:05 ` [PATCH 07/17] watchdog: qcom: add option for standalone watchdog not in timer block Matthew McClintock
2016-03-23 22:40 ` Stephen Boyd
2016-03-25 16:23 ` Guenter Roeck
2016-03-28 16:55 ` Matthew McClintock
2016-03-28 18:13 ` Guenter Roeck
2016-03-28 20:40 ` Matthew McClintock
2016-03-28 21:56 ` Guenter Roeck
2016-03-28 22:21 ` Matthew McClintock
2016-03-23 22:05 ` [PATCH 08/17] watchdog: qcom: configure BARK time in addition to BITE time Matthew McClintock
2016-03-23 22:42 ` Stephen Boyd
2016-03-24 15:46 ` Matthew McClintock
2016-03-24 16:17 ` Guenter Roeck [this message]
2016-03-24 19:49 ` Matthew McClintock
2016-04-07 7:02 ` Guenter Roeck
2016-03-23 22:05 ` [PATCH 09/17] watchdog: qcom: add kpss-standalone to device tree binding Matthew McClintock
2016-03-25 14:15 ` Rob Herring
2016-03-28 17:02 ` Matthew McClintock
2016-03-28 17:26 ` Rob Herring
2016-03-28 18:15 ` Guenter Roeck
2016-03-28 22:22 ` Matthew McClintock
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=20160324161754.GA6515@roeck-us.net \
--to=linux@roeck-us.net \
--cc=andy.gross@linaro.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-watchdog@vger.kernel.org \
--cc=mmcclint@codeaurora.org \
--cc=qca-upstream.external@qca.qualcomm.com \
--cc=sboyd@codeaurora.org \
--cc=wim@iguana.be \
/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).