在 2022-12-05星期一的 10:36 +0000，Conor Dooley写道： > On Fri, Dec 02, 2022 at 02:12:54PM +0800, Icenowy Zheng wrote: > > 在 2022-12-01星期四的 19:18 +0000，Conor Dooley写道： > > > On Wed, Nov 30, 2022 at 12:13:30PM -0600, Rob Herring wrote: > > > > On Tue, Nov 22, 2022 at 03:41:27PM +0800, Icenowy Zheng wrote: > > > > > > > > > > > > > > > 于 2022年11月22日 GMT+08:00 下午3:35:48, Krzysztof Kozlowski > > > > > <krzysztof.kozlowski@xxxxxxxxxx> 写到: > > > > > > On 22/11/2022 08:18, Icenowy Zheng wrote: > > > > > > > 在 2022-11-21星期一的 11:06 +0100，Krzysztof Kozlowski写道： > > > > > > > > On 21/11/2022 05:17, Icenowy Zheng wrote: > > > > > > > > > T-Head OpenC906 is a open-source-licensed fixed- > > > > > > > > > configuration of > > > > > > > > > C906, > > > > > > > > > which is now public and able to be integrated. > > > > > > > > > > > > > > > > > > Add a compatible for the CLINT shipped as part of > > > > > > > > > OpenC906, which > > > > > > > > > should > > > > > > > > > just be ordinary C9xx CLINT. > > > > > > > > > > > > > > > > > > Signed-off-by: Icenowy Zheng <uwu@xxxxxxxxxx> > > > > > > > > > --- > > > > > > > > > Documentation/devicetree/bindings/timer/sifive,clint > > > > > > > > > .yam > > > > > > > > > l | 1 + > > > > > > > > > 1 file changed, 1 insertion(+) > > > > > > > > > > > > > > > > > > diff --git > > > > > > > > > a/Documentation/devicetree/bindings/timer/sifive,clin > > > > > > > > > t.ya > > > > > > > > > ml > > > > > > > > > b/Documentation/devicetree/bindings/timer/sifive,clin > > > > > > > > > t.ya > > > > > > > > > ml > > > > > > > > > index aada6957216c..86703e995e31 100644 > > > > > > > > > --- > > > > > > > > > a/Documentation/devicetree/bindings/timer/sifive,clin > > > > > > > > > t.ya > > > > > > > > > ml > > > > > > > > > +++ > > > > > > > > > b/Documentation/devicetree/bindings/timer/sifive,clin > > > > > > > > > t.ya > > > > > > > > > ml > > > > > > > > > @@ -35,6 +35,7 @@ properties: > > > > > > > > > - const: sifive,clint0 > > > > > > > > > - items: > > > > > > > > > - enum: > > > > > > > > > + - thead,openc906-clint > > > > > > > > > - allwinner,sun20i-d1-clint > > > > > > > > > > > > > > > > Add entries sorted alphabetically. This should be > > > > > > > > squashed > > > > > > > > with > > > > > > > > previous > > > > > > > > patch. > > > > > > > > > > > > > > I make it a seperated patch because I think it's a > > > > > > > questionable > > > > > > > approach. > > > > > > > > > > > > > > If you think it's okay, I will just squash it and put it > > > > > > > as > > > > > > > the second > > > > > > > patch in the next iteration, with adding openc906-plic as > > > > > > > the > > > > > > > first > > > > > > > one. > > > > > > > > > > > > What is a questionable approach? Why commit msg is not > > > > > > saying > > > > > > this? > > > > > > > > > > Ah I mentioned it in the cover letter. The problem is just I > > > > > doubt whether > > > > > binding strings for single SoCs are necessary. > > > > > > > > They are. > > > > > > > > Unless all the quirks/bugs/features are somehow guaranteed to > > > > be > > > > exactly > > > > the same as other SoCs sharing the same compatible string, or > > > > there > > > > is > > > > another mechanism to identify the exact version (e.g. a version > > > > register). > > > > > > Icenowy, > > > > > > Having thought about this a little - are we not *more* likely to > > > see > > > bug/quirk disparity between implementations of the OpenC906 stuff > > > by > > > the very nature of being an open-source IP? > > > > It's an open-source edition of a specific version of the commercial > > IP, > > a fixed configuration. > > > > In addition, maybe we can just retrieve the version infomation via > > a T- > > Head custom CPU configuration register, mcpuid. Despite the > > implementation of this register is weird -- it contains 7 different > > read-only values, with the most significant nibble behaving as an > > index. > > You lot all know the situation here a lot more than I do... > I don't think "letting" people use the bare "thead,c900-foo" makes > much > sense as it gives us no chance to deal with quirks down the line. Well, after rechecking the manual, I found it possible to handle quirks -- T-Head has a custom "mcpuid" CSR (@ RISC-V CSR 0xFC0), which can be used to retrieve some identification info of the core, including its model ID, version, etc; and the T-Head PLIC/CLINT are part of their C906 SoC design that there's another "mapbaddr" CSR that could be used to retrieve the base address of them. So I think it okay to just use "thead,c900-clint" here, and when necessary, try to retrieve mcpuid for dealing with quirks. > I don't think that using "thead,openc906-clint", "thead,c900-clint" > makes all that much sense either, in case someone does something > wacky > with the open-source version of the core. > > That leaves us with either: > "vendor,soc-clint", "thead,openc906-clint", "thead,c900-clint" > or: > "vendor,soc-clint", "thead,c900-clint" > right? > > The first one seems like possibly the better option as you'd kinda > expect that, in a perfect word, all of the open-source IP > implementations would share quirks etc? > > Thanks, > Conor. >
