> On 7 Sep 2022, at 14:31, Michal Orzel <[email protected]> wrote: > > > > On 07/09/2022 15:28, Bertrand Marquis wrote: >> >> Hi Michal, >> >>> On 7 Sep 2022, at 14:09, Michal Orzel <[email protected]> wrote: >>> >>> >>> On 07/09/2022 14:45, Julien Grall wrote: >>>> >>>> On 07/09/2022 13:41, Michal Orzel wrote: >>>>> >>>>> >>>>> On 07/09/2022 14:32, Julien Grall wrote: >>>>>> [CAUTION: External Email] >>>>>> >>>>>> On 07/09/2022 13:12, Michal Orzel wrote: >>>>>>> Hi Julien, >>>>>> >>>>>> Hi Michal, >>>>>> >>>>>>> On 07/09/2022 13:36, Julien Grall wrote: >>>>>>>> >>>>>>>> Hi Henry, >>>>>>>> >>>>>>>> While reviewing the binding sent by Penny I noticed some inconsistency >>>>>>>> with the one you introduced. See below. >>>>>>>> >>>>>>>> On 07/09/2022 09:36, Henry Wang wrote: >>>>>>>>> +- xen,static-heap >>>>>>>>> + >>>>>>>>> + Property under the top-level "chosen" node. It specifies the >>>>>>>>> address >>>>>>>>> + and size of Xen static heap memory. Note that at least a 64KB >>>>>>>>> + alignment is required. >>>>>>>>> + >>>>>>>>> +- #xen,static-heap-address-cells and #xen,static-heap-size-cells >>>>>>>>> + >>>>>>>>> + Specify the number of cells used for the address and size of the >>>>>>>>> + "xen,static-heap" property under "chosen". >>>>>>>>> + >>>>>>>>> +Below is an example on how to specify the static heap in device tree: >>>>>>>>> + >>>>>>>>> + / { >>>>>>>>> + chosen { >>>>>>>>> + #xen,static-heap-address-cells = <0x2>; >>>>>>>>> + #xen,static-heap-size-cells = <0x2>; >>>>>>>> >>>>>>>> Your binding, is introduce #xen,static-heap-{address, size}-cells >>>>>>>> whereas Penny's one is using #{address, size}-cells even if the >>>>>>>> property >>>>>>>> is not "reg". >>>>>>>> >>>>>>>> I would like some consistency in the way we define bindings. Looking at >>>>>>>> the tree, we already seem to have introduced >>>>>>>> #xen-static-mem-address-cells. So maybe we should follow your approach? >>>>>>>> >>>>>>>> That said, I am wondering whether we should just use one set of >>>>>>>> property >>>>>>>> name. >>>>>>>> >>>>>>>> I am open to suggestion here. My only request is we are consistent >>>>>>>> (i.e. >>>>>>>> this doesn't depend on who wrote the bindings). >>>>>>>> >>>>>>> In my opinion we should follow the device tree specification which >>>>>>> states >>>>>>> that the #address-cells and #size-cells correspond to the reg property. >>>>>> >>>>>> Hmmm.... Looking at [1], the two properties are not exclusive to 'reg' >>>>>> Furthermore, I am not aware of any restriction for us to re-use them. Do >>>>>> you have a pointer? >>>>> >>>>> As we are discussing re-usage of #address-cells and #size-cells for >>>>> custom properties that are not "reg", >>>>> I took this info from the latest device tree specs found under >>>>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.devicetree.org%2Fspecifications%2F&data=05%7C01%7Cmichal.orzel%40amd.com%7C83da1eb9d32441cb9e8108da90d4f2d6%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637981541539851438%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=3M9aT3LjCEOhZUHWSbgSSmKppY1Wion4TT3BeKLnWSo%3D&reserved=0: >>>>> "The #address-cells property defines the number of <u32> cells used to >>>>> encode the address field in a child node's reg property" >>>>> and >>>>> "The #size-cells property defines the number of <u32> cells used to >>>>> encode the size field in a child node’s reg property" >>>> >>>> Right. But there is nothing in the wording suggesting that >>>> #address-cells and #size-cells can't be re-used. From [1], it is clear >>>> that the meaning has changed. >>>> >>>> So why can't we do the same? >>> I think this is a matter of how someone reads these sentences. >>> I do not think that such documents need to state: >>> "This property is for the reg. Do not use it for other purposes." >>> The first part of the sentence is enough to inform what is supported. >>> >>> On the other hand, looking at [1] these properties got new purposes >>> so I think we could do the same. Now the question is whether we want that. >>> I think it is doable to just have a single pair of #address/#size >>> properties. >>> For instance xen,shared-mem requiring just 0x1 for address/size >>> and reg requiring 0x2. This would just imply putting additional 0x00. >> >> I think we want in general to reduce complexity when possible. >> Here we are adding a lot of entries in the device tree where we know that >> in all cases having only 2 will work all the time. >> >> I am not convinced by the arguments on not using #address-cells and will >> leave that one to Stefano >> >> But in any case we should only add one pair here for sure, as you say the >> only implication is to add a couple of 0 in the worst case. > I agree. The only drawback is the need to modify the already introduced > properties > to be coherent.
Agree, someone will need to do a pass on the whole doc which might be easier with all things in. Cheers Bertrand > >> >> Cheers >> Bertrand >> >>> >>>> >>>> Cheers, >>>> >>>> -- >>>> Julien Grall
