Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Sat, 29 Jan 2022 13:05:31 -0800
From:   Drew Fustini <dfustini@baylibre.com>
To:     Tony Lindgren <tony@atomide.com>
Cc:     Daniel Lezcano <daniel.lezcano@linaro.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Keerthy <j-keerthy@ti.com>, linux-kernel@vger.kernel.org,
        linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        Tero Kristo <kristo@kernel.org>, Suman Anna <s-anna@ti.com>
Subject: Re: [PATCH 2/2] clocksource/drivers/timer-ti-dm: Handle dra7 timer
 wrap errata i940
Message-ID: <YfWsG0p6to3IJuvE@x1>
References: <20210323074326.28302-1-tony@atomide.com>
 <20210323074326.28302-3-tony@atomide.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20210323074326.28302-3-tony@atomide.com>
Precedence: bulk

On Tue, Mar 23, 2021 at 09:43:26AM +0200, Tony Lindgren wrote:
> There is a timer wrap issue on dra7 for the ARM architected timer.
> In a typical clock configuration the timer fails to wrap after 388 days.
> 
> To work around the issue, we need to use timer-ti-dm percpu timers instead.
> 
> Let's configure dmtimer3 and 4 as percpu timers by default, and warn about
> the issue if the dtb is not configured properly.

Hi Tony,

This causes a conflict for IPU2 which is using timer 3 and 4.

From arch/arm/boot/dts/dra7-ipu-dsp-common.dtsi:

  &ipu2 {
          mboxes = <&mailbox6 &mbox_ipu2_ipc3x>;
          ti,timers = <&timer3>;
          ti,watchdog-timers = <&timer4>, <&timer9>;
  };

I noticed an error ("could not get timer platform device") when booting
mainline on a BeagleBoard X15 (AM578):

  omap-rproc 55020000.ipu: assigned reserved memory node ipu2-memory@95800000
  remoteproc remoteproc1: 55020000.ipu is available
  remoteproc remoteproc1: powering up 55020000.ipu
  remoteproc remoteproc1: Booting fw image dra7-ipu2-fw.xem4, size 3747220
  omap-rproc 55020000.ipu: could not get timer platform device
  omap-rproc 55020000.ipu: omap_rproc_enable_timers failed: -19
  remoteproc remoteproc1: can't start rproc 55020000.ipu: -19

I switched this errata fix to use timer 15 and 16 instead which resolves
the error.  Do you think that is an acceptable solution?

If so, I will post the patch to the list.

Thanks,
Drew