On Saturday 22 September 2007 11:27:05 pm Paul Mackerras wrote: > Rob Landley writes: > > Just to correct a few misconceptions: > > 2) PowerPC uses a device tree supplied by the hardware to identify the > > available hardware, even for stuff living on PCI busses which it could > > theoretically probe for but doesn't. > > The device tree doesn't have to include anything that can be probed > for. On some platforms (e.g. pSeries) we choose to use the device > tree rather than probing, but on most other platforms we probe. > > > I'd be following this more closely if compiling a device tree didn't > > currently require an external utility (dtc or some such) that doesn't > > come with the Linux kernel. No other target platform I've built kernels > > for requires such an environmental dependency. > > No? You haven't built kernels for other platforms that have external > dependencies such as perl, gcc, make, binutils, etc.? :)
Lemme clarify. 1) All of the other platforms have the _same_ requirements. I never had to install anything to build "for arm", "for mips", "for sparc", or for "x86_64". The minimal requirements are: A compiler (gcc/binutils although I'm working on extending tcc to replace these), make, linux kernel, C library (uClibc), busybox, and bash. That's it. You can rebuild it under itself from source with that, on x86, x86-64, arm, mips... Presumably sparc and m68k too (still debugging there). 2) Perl isn't needed to build any target platform I've tried. (I even sent in some patches way back to turn a perl script into a sed script for User Mode Linux to _make_ this the case.) Yes you need perl to build glibc, but not to build uClibc. :) 3) What I'm pointing out is that ppc needs an external dependency none of the other platforms I've tried need. I consider this a bug. I didn't start using "make headers_install" until it stopped needing an external unifdef. > > (This is a problem both for hardwiring the > > device tree into the kernel and for building a new boot rom from the > > linux kernel's ppc boot wrapper that would contain such a device tree to > > feed to the kernel.) > > It's only really been a problem for ps3 so far, since the embedded > guys don't seem to have any difficulty with installing dtc. If the only target that interested me was ppc, then I'd happily install dtc for it. But focusing on cross-platform support as I am, I notice when a platform has different requirements from any of the others. > We are > looking at what to do for ps3 and prep, and the answer may well > involve bundling dtc in the kernel source (it's not too big, around > 3400 lines). Sounds good to me... > Paul. Rob -- "One of my most productive days was throwing away 1000 lines of code." - Ken Thompson. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
