Date:   Mon, 16 Dec 2019 21:39:16 +0530
From:   Anand Moon <linux.amoon@...il.com>
To:     Robin Murphy <robin.murphy@....com>
Cc:     Heiko Stübner <heiko@...ech.de>,
        Lee Jones <lee.jones@...aro.org>,
        Linux Kernel <linux-kernel@...r.kernel.org>,
        Soeren Moch <smoch@....de>, linux-rockchip@...ts.infradead.org
Subject: Re: [PATCH 4/4] mfd: rk808: Convert RK805 to syscore/PM ops

Hi Robin,

On Mon, 16 Dec 2019 at 18:08, Robin Murphy <robin.murphy@....com> wrote:
>
> On 2019-12-16 9:50 am, Anand Moon wrote:
> > Hi Heiko / Robin / Soeren,
> >
> > On Mon, 16 Dec 2019 at 01:57, Heiko Stübner <heiko@...ech.de> wrote:
> >>
> >> Hi Anand,
> >>
> >> Am Sonntag, 15. Dezember 2019, 19:51:50 CET schrieb Anand Moon:
> >>> On Tue, 10 Dec 2019 at 18:54, Robin Murphy <robin.murphy@....com> wrote:
> >>>>
> >>>> RK805 has the same kind of dual-role sleep/shutdown pin as RK809/RK817,
> >>>> so it makes little sense for the driver to have to have two completely
> >>>> different mechanisms to handle essentially the same thing. Bring RK805
> >>>> in line with the RK809/RK817 flow to clean things up.
> >>>>
> >>>> Signed-off-by: Robin Murphy <robin.murphy@....com>
> >>>> ---
> >>
> >> [...]
> >>
> >>> I am sill getting the kernel warning on issue poweroff see below.
> >>> on my Rock960 Model A
> >>> I feel the reason for this is we now have two poweroff callback
> >>> 1  pm_power_off = rk808_device_shutdown
> >>> 2  rk8xx_syscore_shutdown
> >>
> >> Nope, the issue is just the i2c subsystem complaining that the
> >> Rocckhip i2c drives does not provide an atomic-transfer function, see
> >>          "No atomic I2C transfer handler for 'i2c-0'"
> >> in your warning.
> >>
> >> Somewhere it was suggested that the current transfer function just
> >> works as atomic as well.
> >>
> >>
> >>> In my investigation earlier common function for shutdown solve
> >>> the issue of clean shutdown.
> >>
> >> This is simply a result of your syscore-shutdown function running way to
> >> early, before the i2c subsystem switched to using atomic transfers.
> >>
> >> This also indicates that this would really be way to early, as other parts
> >> of the kernel could also still be running.
> >>
> >
> > Yes, you are correct syscore-shutdown initiates
> > shutdown before all the device do clean shutdown.
> >
> > So for best approach for clean atomic shutdown is to use
> >    /* driver model interfaces that don't relate to enumeration  */
> >          void (*shutdown)(struct i2c_client *client);
> > drop the registration of syscore and use core .i2c_shutdown.
>
> Huh? If you understand that the syscore shutdown hook is too early, why
> would it seem a good idea to pull the plug even earlier from driver
> shutdown? Not to mention that your patch as proposed breaks all the
> GPIO-based shutdown flows.
>
Ok opps, I might have missed some thing.
I just look into logs to between syscore shutdown and I2C shutdown
get more insight, so I feel I2C shutdown dose clean shutdown.

> If you really care about avoiding the spurious warning, implement the
> expected polled-mode transfer function in the I2C driver. Trying to hack
> around it by issuing I2C-based shutdown from anywhere other than
> pm_power_off is a waste of everyone's time.

I have tired this I2C shutdown approach earlier, but as their were
issue with clean restart, so I dropped this line.
Then I tired to add restart notifier to handle restart that also
did not work my boards, so I am exploring more.

>
> > I have prepare this patch on top of this series for RTF
> > This patch dose clean shutdown of all the devices before poweroff.
> > see the log below.
> >
> > *Note*: This feature will likely break the clean reboot feature.
> > Rockchip device do not perform clean reboot as some of the IP
> > block are not released before clean reboot and it's remain stuck.
> > Like PCIe and MMC, We need to look into this as well.
>
> As mentioned before, that likely has nothing to do with the PMIC, and
> really sounds like the issue with Trusted Firmware not reenabling all
> the SoC power domains before reset - a fix for that has already been
> identified, see here:
> https://forum.armbian.com/topic/7552-roc-rk3399-pc-renegade-elite/?do=findComment&comment=90289
>
> Robin.
>

If we go with I2C shutdown feature, some how some device will not
release resources and it remains stuck before the initialization next u-boot.
See the log below. https://pastebin.com/xxwvERaz

ATF changes will some into affect after the restart of the devices.
FYI I am testing with all the latest AFT patches from Armbian and latest u-boot.

-Anand

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