Hi, Segher, > DTS sector to the document of booting-without-of.txt file. > > >>> + - #address-cells : Address representation for > >> "rapidio" devices. > >>> + This field represents the number of cells needed > to represent > >>> + the RapidIO address of the registers. For > >> supporting more than > >>> + 32-bits RapidIO address, this field should be <2>. > >>> + See 1) above for more details on defining #address-cells. > >> > >> What does the RapidIO standard say about number of address > >> bits? You want to follow that, so all RapidIO devices can > >> use the same #address-cells, not just the FSL ones. Also, > >> are there different kinds of address spaces on the bus, or > >> is it just one big memory-like space? > > > > I've checked the specification of RapidIO. The supporting of RapidIO > > extended address modes are 66, 50 and 34 bit. > > These three are all two bits more than some "regular" size -- > do those two extra bits have some special meaning perhaps, > like an address space identifier or something? > > > The Freescale's silicons is only support 34 bit address now. > > Do you mean I should not use words -- 'should be <2>'? > > The #address-cells should be assigned according the address mode > > supported by silicon. > > No. The #address-cells is determined by the bus binding, > so that all RapidIO busses on the planet can be represented > in a similar way in the OF device tree. Take for example > the PCI binding, which gives you three address cells -- one > to distinguish between different address spaces (configuration > space, legacy I/O space, memory mapped space) and to contain > some flags (prefetchable vs. non-prefetchable, etc.); the > other two 32-bit cells contain a 64-bit address, although > config and legacy I/O never are more than 32 bit, and many > PCI devices can't do 64-bit addressing at all. > > Now, there is no OF binding for RapidIO yet of course, but > it would be good to start thinking about one while doing > the binding for your specific controller -- it will make > life easier down the line for everyone, including yourself. > How about I add more words here for more clear expression? Such as "<2> for 34 and 50 bit address, <3> for 66 bit address".
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