Dear k...@koi8.net, In message <pine.lnx.4.64ksi.0902171233390.30...@home-gw.koi8.net> you wrote: > > What is unreadable in that code?
It gets out of control. You don;t see any more how much code gets generated from that. > > This is a boot loader with limited resources, not a general purpose > > OS. > > It doesn't matter. It is much better to have a uniform API for all the > future developers to use than to multiply horrible hacks and reinventing the > wheel again and again. Well, I tell you again that size does matter, and may even be a killing point when deciding abouut a patch. > > What makes you insist that we cannot change a variable if we need to > > be able to change one? > > It is NOT just variable. My approach uses i2c _BUS_, not _ADAPTER_. And > number of busses can be bigger than number of adapters (e.g. when some > busses a reached via muxes or switches.) When doing i2c_set_current_bus() > you are switching _NOT_ adapters, but busses. That involves not only > changing that global variable but also reprogramming muxes/switches for > i2c_set_current_bus() to be consistent and hardware independent. Otherwise > your code should know if that particular bus it is switching to is directly > connected or switched and check the bus it is switching from for muxes. If > they are switched, your code should disconnect the current bus switches, > then do that i2c_set_current_bus() and connect the switches to the new bus > after that. > > That means that code MUST somehow know the topology to take appropriate > actions and properly configure those switches. That means you should somehow > describe that topology for each and every board in CONFIG_* terms and make > each and every place at U-Boot that invokes _ANY_ i2c function to take care > of that switching. You convinced me. This code must not be used before relocation to RAM, then. [On the other hand I still wonder why I have never seen any such board appear to me in real life yet. None of the 500+ boards supported in U-Boot uses any such configuration.] > And yes, we DO have some boards with switched I2C busses in U-Boot main tree > so this is NOT a hypothetical situation. Yes, it is, because none of them needs any such switching before relocation. And switching is really simple so far. > > > And the million dollar question -- what is the potential gain? > > > > Indeed. The same question goes to you - where is this added > > complexity really needed? So far nowhere. Are we just talking about > > hypothetical cases, or about a real design? How many such designs? > > Just a single one? > > Please see above. You did not answer my question. Best regards, Wolfgang Denk -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: w...@denx.de I express preference for a chronological sequence of events which precludes a violence. - Terry Pratchett, _The Dark Side of the Sun_ _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
