On Sat, Dec 19, 2015 at 09:39:24PM -0600, Rob Herring wrote: > On Mon, Dec 14, 2015 at 09:53:05PM +0100, Linus Walleij wrote: > > According to commit 2503a5ecd86c002506001eba432c524ea009fe7f > > "ARM: 6201/1: RealView: Do not use outer_sync() on ARM11MPCore > > boards with L220" Some PB11MPCore RealView core tiles have broken > > outer_sync. > > > > We got rid of the custom barriers from the machine by disabling > > outer sync, but that was just for the boardfile case. We have > > to be able to do the same in the device tree case. > > > > Since __l2c_init() is cloning and copying the L2C vtable, > > we pass an argument to this function to optionally numb > > the outer sync operation if desired, before initializing > > the cache. > > > > After this we can set up the cache correctly on the RealView > > PB11MPCore. This was tested on a PB11MPCore known to have the > > issue. Before this, spurious crashes would occur if we try to > > set up the cache properly, after this it boots rock solid. > > > > Cc: Russell King <linux@xxxxxxxxxxxxxxxx> > > Cc: Arnd Bergmann <arnd@xxxxxxxx> > > Cc: devicetree@xxxxxxxxxxxxxxx > > Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx> > > --- > > ChangeLog v2->v3: > > - Update description, reference Catalins initial commit in the > > commit blurb. > > --- > > Documentation/devicetree/bindings/arm/l2cc.txt | 3 +++ > > arch/arm/mm/cache-l2x0.c | 13 ++++++++++--- > > 2 files changed, 13 insertions(+), 3 deletions(-) > > > > diff --git a/Documentation/devicetree/bindings/arm/l2cc.txt b/Documentation/devicetree/bindings/arm/l2cc.txt > > index d181b7c4c522..416864e9dc92 100644 > > --- a/Documentation/devicetree/bindings/arm/l2cc.txt > > +++ b/Documentation/devicetree/bindings/arm/l2cc.txt > > @@ -75,6 +75,9 @@ Optional properties: > > specified to indicate that such transforms are precluded. > > - arm,parity-enable : enable parity checking on the L2 cache (L220 or PL310). > > - arm,parity-disable : disable parity checking on the L2 cache (L220 or PL310). > > +- arm,outer-sync-disable : disable the outer sync operation on the L2 cache. > > + Some core tiles, especially ARM PB11MPCore have a faulty L220 cache that > > + will randomly hang unless outer sync operations are disabled. > > This is also useful on Highbank as a feature where all DMA goes thru the > ACP port and there should not be a need to flush the L2 write buffer. > But I already optimized the performance critical register accesses with > _relaxed variants, so it doesn't really matter. I don't think any other > platform cares, therefore: > > Acked-by: Rob Herring <robh@xxxxxxxxxx> Thanks. It would be nice to have a faster response though, because Linus Walleij put this in the patch system on the 15th December, and I could have applied it without waiting for DT people to comment. The good thing is that I _have_ the patch system, which allows me to temporarily ignore patches (provided I remember) while people chew the cud on stuff like this. However, I'd _much_ rather prefer the authors to hold back the patches until they get "approved" *before* sending them there, so I don't have to find and remember to track the status of each patch on the mailing list. -- RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
