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From:   Mathieu Malaterre <malat@debian.org>
Date:   Fri, 25 Jan 2019 09:21:51 +0100
Message-ID: <CA+7wUsxhjiLQ6n40AZGWHeqL0o8NvR3hn+pWgmh=7hdPTBrKtg@mail.gmail.com>
Subject: Re: [PATCH v8 00/26] Ingenic TCU patchset v8
To:     Paul Cercueil <paul@crapouillou.net>
Cc:     Paul Burton <paul.burton@mips.com>,
        James Hogan <jhogan@kernel.org>,
        Ezequiel Garcia <ezequiel@collabora.co.uk>,
        PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>, linux-mips@vger.kernel.org,
        linux-clk@vger.kernel.org
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Paul,

On Thu, Jan 24, 2019 at 10:41 PM Paul Cercueil <paul@crapouillou.net> wrote:
>
> Hi Mathieu,
>
> Le jeu. 24 janv. 2019 à 18:26, Mathieu Malaterre <malat@debian.org> a
> écrit :
> > Paul,
> >
> > On Wed, Dec 12, 2018 at 11:09 PM Paul Cercueil <paul@crapouillou.net>
> > wrote:
> >>
> >>  Hi,
> >>
> >>  Here's the version 8 and hopefully final version of my patchset,
> >> which
> >>  adds support for the Timer/Counter Unit found in JZ47xx SoCs from
> >>  Ingenic.
> >
> > I can no longer boot my MIPS Creator CI20 with this series (merged
> > opendingux/for-upstream-timer-v8).
> >
> > Using screen+ttyUSB, I can see messages stopping at:
> >
> > ...
> > [  OK  ] Started Cgroup management daemon.
> >          Starting Regular background program processing daemon...
> > [  OK  ] Started Regular background program processing daemon.
> >          Starting System Logging Service...
> >          Starting Provide limited super user privileges to specific
> > users...
> >          Starting Restore /etc/resolv.conf if the system cras...s
> > shut down....
> >          Starting WPA supplicant...
> >          Starting D-Bus System Message Bus...
> > [  OK  ] Started D-Bus System Message Bus.
> >
> > Nothing really stands out in the error messages. Could you suggest
> > things to try out to get into a bootable state ?
>
> I'm debugging it right now on jz4740, it seems to happen when the
> clocksource
> from the ingenic-timer driver is used. Is it your case? It should not
> happen
> if you have CONFIG_INGENIC_OST set.

Here is what I see:

$ grep CONFIG_INGENIC_OST arch/mips/configs/ci20_defconfig
CONFIG_INGENIC_OST=y
$ make O=ci20 ARCH=mips CROSS_COMPILE=mipsel-linux-gnu- ci20_defconfig
$ grep CONFIG_INGENIC_OST ci20/.config
CONFIG_INGENIC_OST=y

The setting is coming from your commit:

8f66e6b9c98f MIPS: CI20: defconfig: enable OST driver

In an attempt to solve the symptoms I even played with the clock rates
with no success:

&tcu {
/* 3 MHz for the system timer and clocksource */
assigned-clocks = <&tcu TCU_CLK_TIMER0>, <&tcu TCU_CLK_TIMER1>;
assigned-clock-rates = <750000>, <750000>;
};


> >>  The big change is that the timer driver has been simplified. The
> >> code to
> >>  dynamically update the system timer or clocksource to a new channel
> >> has
> >>  been removed. Now, the system timer and clocksource are provided as
> >>  children nodes in the devicetree, and the TCU channel to use for
> >> these
> >>  is deduced from their respective memory resource. The PWM driver
> >> will
> >>  also deduce from its memory resources whether a given PWM channel
> >> can be
> >>  used, or is reserved for the system timers.
> >>
> >>  Kind regards,
> >>  - Paul Cercueil
> >>
>