[PATCH] ARM: exynos_defconfig: disable CONFIG_EXYNOS5420_MCPM; not stable

[k.kozlowski@samsung.com (Krzysztof Kozlowski)]

On wto, 2014-11-25 at 09:47 +0100, Krzysztof Kozlowski wrote:
> On pon, 2014-11-24 at 19:20 -0800, Kevin Hilman wrote:
> > On Mon, Nov 24, 2014 at 5:50 PM, Kukjin Kim <kgene@kernel.org> wrote:
> > > Olof Johansson wrote:
> > >>
> > >> On Mon, Nov 24, 2014 at 5:37 PM, Olof Johansson <olof@lixom.net> wrote:
> > >> > On Mon, Nov 24, 2014 at 5:35 PM, Kevin Hilman <khilman@kernel.org> wrote:
> > >> >> On Mon, Nov 24, 2014 at 4:25 PM, Olof Johansson <olof@lixom.net> wrote:
> > >> >>> On Mon, Nov 24, 2014 at 11:51 AM, Kevin Hilman <khilman@kernel.org> wrote:
> > >> >>>>
> > >> >>>> Is anyone at Samsung actually looking into these MCPM issues?
> > >> >>>
> > >> >>> Hi Kevin,
> > >> >>>
> > >> >>> What hardware are you having problems with? 5420 or 5422/5800?
> > >> >>
> > >> >> Yes.  :)
> > >> >>
> > >> >> exynos5420-arndale-octa:
> > >> >> http://storage.armcloud.us/kernel-ci/mainline/v3.18-rc6/arm-exynos_defconfig/boot-exynos5420-
> > >> arndale-octa.html
> > >> >> exynos5422-odroid-xu3:
> > >> >> http://storage.armcloud.us/kernel-ci/mainline/v3.18-rc6/arm-exynos_defconfig/boot-exynos5422-
> > >> odroid-xu3.html
> > >> >>
> > >> >> My boot tests seem to pass fine because I have such a minimal
> > >> >> userspace, but Tyler Baker reported that with a "real" userspace, he
> > >> >> can't boot to a shell:
> > >> >>
> > >> >>   http://lists.infradead.org/pipermail/linux-arm-kernel/2014-September/286203.html
> > >> >
> > > Hmm...his report was in Sep...I think it should be fine with current -next?
> > 
> > No, it is still broken in linux-next (as I stated above.)
> > 
> > Moreover, earlier in this thread you mentioned you were merging some
> > MCPM patches that should address this, but did not respond when I
> > asked which patches you thing should address this issue
> > 
> > > To be honest, since I don't have the exynos5420 arndale, chromebook...but smdk
> > > which has different bootloader, I couldn't test it...I'll try to make a test
> > > farm like you guys...
> > 
> > Do you have some colleagues with any other 542x hardware?  I had
> > assumed that linux-next was being better tested on the publicaly
> > available, and widely available boards like odroid-xu3 and
> > Chromebook2, but I've come to realize the hard way that that is not
> > the case.  You mention your board has a different bootloader.  Do you
> > suspect there's a bootloader issue on these other platforms?  If so,
> > could you elaborate on possible fixes?  I'm more than willing to test
> > any proposed fixes, but I'm not familiar enough yet with these SoCs to
> > figure out the underlying issues alone.
> > 
> > Until you have a working board farm, you could start having a closer
> > look at the boot logs we're already producing.  Admittedly linux-next
> > broken in many ways besides this one for exynos currently, but it has
> > been having these imprecise aborts well before the other recent
> > issues.
> > 
> > Also, It's very possible that this issue is not even MCPM related at
> > all, and MCPM is just uncovering a previously hidden bug.  It would be
> > very helpful if people more familiar with this hardware and SoC would
> > investigate bug reports like these.
> 
> Interesting thing can be found in exynos5420.dtsi:
> mdma1: mdma at 11C10000 {
> 	...
> 	/*
> 	 * MDMA1 can support both secure and non-secure
> 	 * AXI transactions. When this is enabled in the kernel
> 	 * for boards that run in secure mode, we are getting
> 	 * imprecise external aborts causing the kernel to oops.
> 	 */
> 	status = "disabled";
> };
> 
> I am booting Arndale Octa on some other config and exynos. However with
> or without MCPM the imprecise aborts are still present (but not fatal,
> shell comes up).
> 
> My board boots also under secure firmware (I am using Linaro's ubuntu
> image). Maybe that is the cause?

One update: some fatal imprecise aborts (hanging boot) happen also on
exynos_defconfig without MCPM. It looks random... one boot fails, next
succeeds (however also with "imprecise external abort" message but shell
comes up).

Best regards,
Krzysztof