Hi Heiko, On Thu, 01 Aug 2013 10:38:15 +0200, Heiko Schocher <h...@denx.de> wrote:
> Hello Albert, > > Am 01.08.2013 08:53, schrieb Albert ARIBAUD: > > Hi Heiko, > > > > On Thu, 01 Aug 2013 08:02:42 +0200, Heiko Schocher<h...@denx.de> wrote: > > > >>> I suppose you could. It seems conceptually /far/ simpler to just scan > >>> the DT once up-front rather than having to defer all this stuff until > >> > >> on the other hand we ring for every ms boot time ... and here we want > >> to scan a complete dt with maybe a lot of nodes, we do not want to > >> use? > > > > Scanning all of DT seems to imply it has no strict or standard > > ordering. Could we mandate, suggest, of make it so that all entries in > > the DT needed at _f time are put first, and even maybe place an "end of > > _f" custom marker in DT to delimit them? (I assume that, for the sake of > > I do not know, if this is possible, as I think the DT used in U-Boot > should be the same as used in linux ... or? > > > Postel-ism, anything in DT which is not understandable is skipped, so > > other users of the DT than us would not even be annoyed by such a > > marker) > > > > This way, we'd avoid wasting time scanning most of the DT in this case. > > Hmm.. why should we introduce such things, instead of scanning the > node only if we need it? >From the "we want to scan a complete dt with maybe a lot of nodes, we do not want to use?" above, I inferred that one problem here was having to waste time going through the whole DT looking only for info needed at _f stage. This is why I made the suggestion above for that problem. Sorry if I did not understand this properly. > We have "only" the problem, that we could not write to data at this > moment ... but this problem should be solved in a seperate topic. > I2C is usable before relocation, the problem is in conjunction with > dt, that we can not save for example the base address of the controller, > which we get from the DT ... If I understand it correct! > > So we need an option when using dt, that we have (small ram) in which > we can write some parameters parsed from dt ... > > I think this problem have all subsystems used before relocation. > (for example: environment on a spi flash?) > > As Wolfgang said: > "Agreed - actually we're entering an area hear that smells pretty > strong like device model reorganization :-)" > > BTW: How is this problem solved with the device model approach? > > > Note: I confess I don't even know at the moment how DT is structured, so > > I may have talked complete nonsense above. If so, please forgive me and > > point me to some DT 101 course for me to avoid shame (at least on this > > topic) in the future. > > bye, > Heiko Amicalement, -- Albert. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
