Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > linux.kernel > #1364283

Re: [PATCH 08/17] watchdog: qcom: configure BARK time in addition to BITE time

From Matthew McClintock <mmcclint@codeaurora.org>
Newsgroups linux.kernel
Subject Re: [PATCH 08/17] watchdog: qcom: configure BARK time in addition to BITE time
Date 2016-03-24 16:50 +0100
Message-ID <rgfGh-4EY-7@gated-at.bofh.it> (permalink)
References <rfZ8u-1se-3@gated-at.bofh.it> <rfZ8v-1se-33@gated-at.bofh.it> <rfZLc-1IM-15@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw


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.

-M

Back to linux.kernel | Previous | NextPrevious in thread | Next in thread | Find similar | Unroll thread


Thread

[PATCH 08/17] watchdog: qcom: configure BARK time in addition to BITE time Matthew McClintock <mmcclint@codeaurora.org> - 2016-03-23 23:10 +0100
  Re: [PATCH 08/17] watchdog: qcom: configure BARK time in addition to  BITE time Stephen Boyd <sboyd@codeaurora.org> - 2016-03-23 23:50 +0100
    Re: [PATCH 08/17] watchdog: qcom: configure BARK time in addition to BITE time Matthew McClintock <mmcclint@codeaurora.org> - 2016-03-24 16:50 +0100
      Re: [PATCH 08/17] watchdog: qcom: configure BARK time in addition to  BITE time Guenter Roeck <linux@roeck-us.net> - 2016-03-24 17:20 +0100
        Re: [PATCH 08/17] watchdog: qcom: configure BARK time in addition to BITE time Matthew McClintock <mmcclint@codeaurora.org> - 2016-03-24 20:50 +0100

csiph-web