| Message ID | 1450126385-14517-1-git-send-email-linus.walleij@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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@arm.linux.org.uk> > Cc: Arnd Bergmann <arnd@arndb.de> > Cc: devicetree@vger.kernel.org > Signed-off-by: Linus Walleij <linus.walleij@linaro.org> > --- > 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@kernel.org> Rob
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@arm.linux.org.uk> > > Cc: Arnd Bergmann <arnd@arndb.de> > > Cc: devicetree@vger.kernel.org > > Signed-off-by: Linus Walleij <linus.walleij@linaro.org> > > --- > > 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@kernel.org> 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.
On Sun, Dec 20, 2015 at 5:11 PM, Russell King - ARM Linux <linux@arm.linux.org.uk> wrote: > 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. OK sorry, I guess I was a bit trigger happy as my RealView was booting so nicely and all. Yours, Linus Walleij
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. - prefetch-data : Data prefetch. Value: <0> (forcibly disable), <1> (forcibly enable), property absent (retain settings set by firmware) - prefetch-instr : Instruction prefetch. Value: <0> (forcibly disable), diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c index 3f3008e5c662..9f9d54271aad 100644 --- a/arch/arm/mm/cache-l2x0.c +++ b/arch/arm/mm/cache-l2x0.c @@ -790,7 +790,7 @@ static const struct l2c_init_data l2c310_init_fns __initconst = { }; static int __init __l2c_init(const struct l2c_init_data *data, - u32 aux_val, u32 aux_mask, u32 cache_id) + u32 aux_val, u32 aux_mask, u32 cache_id, bool nosync) { struct outer_cache_fns fns; unsigned way_size_bits, ways; @@ -866,6 +866,10 @@ static int __init __l2c_init(const struct l2c_init_data *data, fns.configure = outer_cache.configure; if (data->fixup) data->fixup(l2x0_base, cache_id, &fns); + if (nosync) { + pr_info("L2C: disabling outer sync\n"); + fns.sync = NULL; + } /* * Check if l2x0 controller is already enabled. If we are booting @@ -925,7 +929,7 @@ void __init l2x0_init(void __iomem *base, u32 aux_val, u32 aux_mask) if (data->save) data->save(l2x0_base); - __l2c_init(data, aux_val, aux_mask, cache_id); + __l2c_init(data, aux_val, aux_mask, cache_id, false); } #ifdef CONFIG_OF @@ -1724,6 +1728,7 @@ int __init l2x0_of_init(u32 aux_val, u32 aux_mask) struct resource res; u32 cache_id, old_aux; u32 cache_level = 2; + bool nosync = false; np = of_find_matching_node(NULL, l2x0_ids); if (!np) @@ -1762,6 +1767,8 @@ int __init l2x0_of_init(u32 aux_val, u32 aux_mask) if (cache_level != 2) pr_err("L2C: device tree specifies invalid cache level\n"); + nosync = of_property_read_bool(np, "arm,outer-sync-disable"); + /* Read back current (default) hardware configuration */ if (data->save) data->save(l2x0_base); @@ -1776,6 +1783,6 @@ int __init l2x0_of_init(u32 aux_val, u32 aux_mask) else cache_id = readl_relaxed(l2x0_base + L2X0_CACHE_ID); - return __l2c_init(data, aux_val, aux_mask, cache_id); + return __l2c_init(data, aux_val, aux_mask, cache_id, nosync); } #endif
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@arm.linux.org.uk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: devicetree@vger.kernel.org Signed-off-by: Linus Walleij <linus.walleij@linaro.org> --- 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(-)