From: Leif Lindholm <leif.lindholm@linaro.org>
To: Rob Herring <robherring2@gmail.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linaro Patches <patches@linaro.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
Mark Rutland <mark.rutland@arm.com>
Subject: Re: [PATCH 0/3] of: dts: enable memory@0 quirk for PPC32 only
Date: Sat, 19 Apr 2014 01:36:34 +0100 [thread overview]
Message-ID: <20140419003634.GI5904@bivouac.eciton.net> (raw)
In-Reply-To: <CAL_Jsq+L14rgYq5swC3H109DThiyDajmTJpO=y562jcE97K-fg@mail.gmail.com>
On Fri, Apr 18, 2014 at 04:28:17PM -0500, Rob Herring wrote:
> >> > Apart from the current code permitting recreating a 15+ year old
> >> > firmware bug into completely new platform ports?
> >>
> >> I would prefer to see a "WARN_ON(!IS_ENABLED(CONFIG_PPC32));" added here.
> >
> > In addition to, or instead of, the QUIRK ifdef?
>
> Instead of because I don't see how you handle the ARM board
> compatibility with the ifdef. (And please, no ifdef for that board).
Umm, according to my memory as well as my sent mail folder, I cc:d you
on v2 of part 3. Could you have a look at that, please?
A WARN_ON would still mean this ancient workaround for a specific ppc32
platform remains enabled on ~10 architectures that don't use it.
> >> Really, I would like to see quirks like this fixed up out of line from
> >> the normal flow somewhat like how PCI quirks are handled. So in this
> >> example, we would just add the missing property to the dtb for the
> >> broken platform before doing the memory scan. That does then require
> >> libfdt which is something I'm working on.
> >
> > Getting rid of all this handling from generic code would clearly be
> > preferable. Is that code going in in the near future, or could we add
> > the quirk as a stopgap?
>
> Some sort of quirk infrastructure is not going to happen soon. It's
> just an idea bouncing in my head ATM.
Mmm...
> > What would be the effect of the UEFI code adding all its memblocks,
> > minus the reserved areas, and then the DT code doing a memblock_add
> > of all RAM (including reserved areas)? Would memblock_reserve()s on
> > the protected regions suffice to prevent crazy stuff from happening?
>
> So use UEFI to add the memory, but then add reserved areas with DT?
No, to add memory and reserved areas based on UEFI memory map.
And then add any memory@0/!type nodes as well, if they're left around.
> I'm not sure I follow, but even if I did I don't know memblock code
> well enough to say what it would do.
If we did end up with stray memory@0/!type nodes, we could initialise
memblock multiple times with overlapping but incompatible areas.
And I don't know if that would be a problem. Which makes me a little
bit nervous.
/
Leif
next prev parent reply other threads:[~2014-04-19 0:33 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-17 17:41 [PATCH 0/3] of: dts: enable memory@0 quirk for PPC32 only Leif Lindholm
2014-04-17 17:41 ` [PATCH 1/3] arm: dts: add device_type="memory" for ste-ccu8540 Leif Lindholm
2014-04-22 7:39 ` Lee Jones
2014-04-22 13:09 ` Grant Likely
2014-04-22 13:26 ` Linus Walleij
2014-05-15 14:50 ` Grant Likely
2014-04-17 17:42 ` [PATCH 2/3] mips: dts: add device_type="memory" where missing Leif Lindholm
2014-04-18 17:16 ` John Crispin
2014-04-22 13:13 ` Grant Likely
2014-05-15 14:50 ` Grant Likely
2014-04-17 17:42 ` [PATCH 3/3] of: Handle memory@0 node on PPC32 only Leif Lindholm
2014-04-18 8:04 ` Geert Uytterhoeven
2014-04-18 12:59 ` Leif Lindholm
2014-04-18 13:11 ` Geert Uytterhoeven
2014-04-21 12:56 ` Rob Herring
2014-04-23 10:35 ` Mark Rutland
2014-04-22 13:35 ` Grant Likely
2014-04-23 10:45 ` Mark Rutland
2014-04-23 11:14 ` Geert Uytterhoeven
2014-04-23 13:10 ` Grant Likely
2014-04-24 9:26 ` Leif Lindholm
2014-05-15 14:59 ` Grant Likely
2014-04-18 0:43 ` [PATCH 0/3] of: dts: enable memory@0 quirk for " Rob Herring
2014-04-18 12:48 ` Leif Lindholm
2014-04-18 15:37 ` Rob Herring
2014-04-18 20:13 ` Leif Lindholm
2014-04-18 21:28 ` Rob Herring
2014-04-19 0:36 ` Leif Lindholm [this message]
2014-04-22 13:08 ` Grant Likely
2014-04-22 14:05 ` Leif Lindholm
2014-04-23 13:15 ` Grant Likely
2014-04-23 17:25 ` Leif Lindholm
2014-04-23 13:17 ` Grant Likely
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