On Tue, Jan 07, 2014 at 08:12:39PM +0000, Stephen Boyd wrote: > On 01/07, Lorenzo Pieralisi wrote: > > > > Not sure this binding (cache node) belongs in cpus.txt > > > > I am working on defining cache bindings for ARM within the C-state > > standardization effort: > > > > http://lists.infradead.org/pipermail/linux-arm-kernel/2013-December/215543.html > > Thanks I'll take a look. > > > > > > + > > > + Description: Describes a cache in an ARM based system > > > + > > > + - compatible > > > + Usage: required > > > + Value type: <string> > > > + Definition: shall contain at least "cache" > > > > It is a bit vague, can't we just follow the ePAPR compatible definition ? > > See posting above. > > Hm.. I thought this did follow the ePAPR spec. I see 'compatible, > required, string, A standard property. The value shall include > the string "cache".' Looks the same? Sorry, my bad, you are right. > And I see 'cache-level, required, u32, Specifies the level in the > cache hierarchy. For example, a level 2 cache has a value of > <2>.' We need to define it properly for ARM, I am not sure we can use level as defined in CLIDR, I need to think more about this. > > > > > + > > > + - cache-level > > > + Usage: required > > > + Value type: <u32> > > > + Definition: level in the cache heirachy > > > > "hierarchy". > > Thanks. > > > I have a problem with the cache level definition, and in > > particular the numbering, ie what the level number represents. If we > > mean the cache level seen through the CLIDR and co., it is hard to use > > it for shared caches since the level seen by different CPUs can actually > > be different, or put it differently the level number might not be unique for > > a shared cache. I need to think about a proper way to sort this out. > > > > Ok. I don't even use this property in my driver. All I really > need is the phandle from cpus pointing to the L2 and the > interrupts property in the L2 node. > > How do you want to proceed here? If your cache binding goes > through I would just need to add the interrupts part. Or you > could even add that part in the same patch, you could have my > signed-off-by for that. Ok, I will try to update the bindings with the interrupt part and copy you in, even though the level definition worries me a bit, it is an important property for power management and I need to find a proper solution before bindings can get accepted (basically the problem is: if different CPUs can see a cache at different levels as defined in the CLIDR we cannot describe a cache with a single cache level or put it differently, level can not represent the value in the CLIDR hence we need to describe it differently). Lorenzo -- 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
