Messages in this thread | | | Subject | Re: [PATCH 1/3] ARM: uniphier: add outer cache support | From | Rob Herring <> | Date | Tue, 8 Sep 2015 19:06:27 -0500 |
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On 09/08/2015 08:09 AM, Linus Walleij wrote: > On Fri, Aug 28, 2015 at 12:24 PM, Masahiro Yamada > <yamada.masahiro@socionext.com> wrote: >> 2015-08-26 22:39 GMT+09:00 Linus Walleij <linus.walleij@linaro.org>: > >>> cache-unified and cache-level are *not* optional and should be required. >> >> "cache-unified" is mentioned in "3.7.3 Internal (L1) Cache Properties" >> (Table 3-8), >> but it is not in "3.8 Multi-level and Shared Caches" (Table 3-9) >> >> Are the rules in Table 3-8 also applied for L2? > > Your guess is as good as mine unless someone involved in > actually writing that spec says something :/
Maybe you'd have to be crazy to have Harvard cache for 2nd+ level. I've got no clue. Doesn't hurt to have it.
> >>> (I'm just assuming this cache is unified, anything else would be baffling.) >> >> In fact, unified/harvard is configurable thru a register of this cache >> controller. > > Jesus Christ.
Hardware designers either hate software folks or ensure our job security.
> >> It is usually used as a unified cached, though. > > I would, too. > >> So,I am planning to use the same compatible for L2 and L3, like this: >> >> >> l2-cache@500c0000 { >> compatible = "socionext,uniphier-cache"; >> reg = <0x500c0000 0x2000>, <0x503c0100 0x8>, >> <0x506c0000 0x400>; >> cache-unified; >> cache-level = <2>; >> next-level-cache = <&L2>;
Next level of the L2 is the L2?
>> cache-size = <0x200000>; >> cache-sets = <256>; >> cache-line-size = <128>; >> }; >> >> /* Not all of UniPhier SoCs have L3 cache */ >> l3-cache@500c8000 { >> compatible = "socionext,uniphier-cache"; >> reg = <0x500c8000 0x2000>, <0x503c8100 0x8>, >> <0x506c8000 0x400>; >> cache-unified; >> cache-level = <3>; >> cache-size = <0x400000>; >> cache-sets = <256>; >> cache-line-size = <256>; >> }; > > This LooksGoodToMe. > >> The Table 3-9 in ePAPR v1.1 says >> the compatible should be "cache", but I do not think it makes sense here. > > Agree.
It could be useful for finding all cache nodes, but we've generally failed to use it, so at this point it doesn't matter.
Rob
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