Re: [PATCH v3 0/5] Add SMP bringup support for mt65xx socs

[Matthias Brugger <matthias.bgg@gmail.com>]

On Wednesday, August 05, 2015 11:31:15 PM Russell King - ARM Linux wrote:
> On Wed, Aug 05, 2015 at 08:44:11PM +0200, Matthias Brugger wrote:
> > On Tuesday, July 14, 2015 01:18:26 PM Yingjoe Chen wrote:
> > > This series add SMP brinup support for MediaTek SoCs. This is based
> > > on v4.2-rc1 and Matthias' next branch (for dts parts).
> > > 
> > > There are similar but different SMP bringup up methods on MediaTek
> > > mt65xx and mt81xx. On MT8135 & MT8127, system boots with a trustzone
> > > firmware. Others, like MT6589, doesn't have trustzone, and run kernel
> > > directly in secure world.
> > > 
> > > Patch 1 enable arch timer support.
> > > Patch 2,3 add support for cpu enable-method "mediatek,mt6589-smp" and
> > > "mediatek,mt81xx-tz-smp", which support Mediatek SMP bringup for non-TZ
> > > and TZ platform.
> > > Patch 4,5 finally enable SMP bringup for mt8135 and mt8127.
> > > 
> > > Changes in v3:
> > > - The first 2 patches in v2 are merged in v4.2-rc1.
> > > - Patch 3~4 in v2 are moved to another series [1]
> > > - platsmp.c changes based on Stephen's suggestion
> > > - Change cpu enable-method name to "mediatek,mt6589-smp"
> > > 
> > > Changes in v2:
> > > - Fix boot issue for THUMB2 kernel.
> > > - Not enable GPT_CLK_EVT when setup to fix GPT spurious interrupt issue
> > > - Change platsmp.c according to Matthias' suggestion
> > > http://lists.infradead.org/pipermail/linux-mediatek/2015-May/000714.html
> > > 
> > > v1:
> > > http://lists.infradead.org/pipermail/linux-mediatek/2015-May/000528.html
> > > 
> > > [1]
> > > http://lists.infradead.org/pipermail/linux-mediatek/2015-July/001544.htm
> > > l
> > > 
> > > Matthias Brugger (1):
> > >   ARM: mediatek: enable gpt6 on boot up to make arch timer working
> > > 
> > > Yingjoe Chen (4):
> > >   devicetree: bindings: add new SMP enable method Mediatek SoC
> > >   ARM: mediatek: add smp bringup code
> > >   ARM: dts: mt8135: enable basic SMP bringup for mt8135
> > >   ARM: dts: mt8127: enable basic SMP bringup for mt8127
> > >  
> > >  Documentation/devicetree/bindings/arm/cpus.txt |   2 +
> > >  arch/arm/boot/dts/mt8127.dtsi                  |  16 +++
> > >  arch/arm/boot/dts/mt8135.dtsi                  |  16 +++
> > >  arch/arm/mach-mediatek/Makefile                |   3 +
> > >  arch/arm/mach-mediatek/mediatek.c              |  27 +++++
> > >  arch/arm/mach-mediatek/platsmp.c               | 144
> > > 
> > > +++++++++++++++++++++++++ 6 files changed, 208 insertions(+)
> > > 
> > >  create mode 100644 arch/arm/mach-mediatek/platsmp.c
> > 
> > Applied to v4.2-next/soc-2 and v4.2-next/dts-2
> 
> I've just NAK'd one of the patches in this set; I don't tend to even see
> mediatek patches normally, as they all head into my junk mailfolder
> because mediatek's mail server setup is truely abysmal (it has broken
> reverse DNS - the DNS positively says that the mail server is not a
> legit owner of the name it claims to be.)
> 
> The problem is that this patch series uses memblock_reserve() way after
> the memory has been transitioned out of memblock's control, so actually
> this has no effect.
> 
> I've seen a number of patches doing this.  I'm not sure what's soo friggin
> hard for people to understand: memblock is about the EARLY stages of
> getting the system up and running.  Once the memory has been handed
> over to the kernel's memory management, memblock MUST NOT BE USED to
> reserve memory.
> 
> There is one place, and one place only in the ARM kernel where
> memblock_reserve() is possible, and that's in the ->reserve machine
> callback.  NOWHERE ELSE is permissible.

OK, I just dropped the patches. Thanks for reviewing this.

Matthias