On 12/3/07, Stephen Neuendorffer <[EMAIL PROTECTED]> wrote: > I was misled by the prior language. I've attempted to clarify how > 'ranges' are used, in particular, how to get a 1:1 mapping. > > Signed-off-by: Stephen Neuendorffer <[EMAIL PROTECTED]>
Acked-by: Grant Likely <[EMAIL PROTECTED]> > --- > Documentation/powerpc/booting-without-of.txt | 11 +++++++---- > 1 files changed, 7 insertions(+), 4 deletions(-) > > diff --git a/Documentation/powerpc/booting-without-of.txt > b/Documentation/powerpc/booting-without-of.txt > index e9a3cb1..aad8bf5 100644 > --- a/Documentation/powerpc/booting-without-of.txt > +++ b/Documentation/powerpc/booting-without-of.txt > @@ -711,13 +711,14 @@ define a bus type with a more complex address format, > including things > like address space bits, you'll have to add a bus translator to the > prom_parse.c file of the recent kernels for your bus type. > > -The "reg" property only defines addresses and sizes (if #size-cells > -is non-0) within a given bus. In order to translate addresses upward > +The "reg" property only defines addresses and sizes (if #size-cells is > +non-0) within a given bus. In order to translate addresses upward > (that is into parent bus addresses, and possibly into CPU physical > addresses), all busses must contain a "ranges" property. If the > "ranges" property is missing at a given level, it's assumed that > -translation isn't possible. The format of the "ranges" property for a > -bus is a list of: > +translation isn't possible, i.e., the registers are not visible on the > +parent bus. The format of the "ranges" property for a bus is a list > +of: > > bus address, parent bus address, size > > @@ -735,6 +736,8 @@ fit in a single 32-bit word. New 32-bit powerpc boards > should use a > 1/1 format, unless the processor supports physical addresses greater > than 32-bits, in which case a 2/1 format is recommended. > > +Alternatively, the "ranges" property may be empty, indicating that the > +registers are visible on the parent bus, with 1:1 address translation. > > 2) Note about "compatible" properties > ------------------------------------- > -- > 1.5.3.4 > > > > -- Grant Likely, B.Sc., P.Eng. Secret Lab Technologies Ltd. [EMAIL PROTECTED] (403) 399-0195 _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
