Subject: Re: Advice on adding support for a new Platform
To: None <>
From: Thomas J. Merritt <>
List: port-arm
Date: 06/06/2001 17:23:29
|<><><><><> Original message from Ben Harris  <><><><><>
|On Thu, 7 Jun 2001, Chris Gilbert wrote:
|> On Wednesday 06 June 2001  9:06 pm, Thomas J. Merritt wrote:
|> > I interested in porting NetBSD/ARM to a platform based upon the Cirrus
|> > Logic EP7312.  The EP7312 has an ARM 720T core plus a bunch of peripherals
|> > and is similar to the EP7209.  The board is running OpenFirmware.
|> > OpenFirmware is able to net load the kernel as an ELF image.  I would
|> > appreciate any advice on how to attack the port.
|> I presume that the 720T is a thumb based chipset (not looked for the spec on
|> it yet)  So certainly an issue is that we currently don't have support for
|> thumb in NetBSD (not sure if gcc can do Thumb either).  If it's not Thumb, it
|> maybe a matter of adding the checks for it's CPU ID and with a bit of luck
|> it'll look enough like an ARM7 core that we'll work with it :)
|It's basically a 710T with the fast context switch extension, so John
|Fremlin's 7TDMI code should provide all the necessary CPU support.

The 720T extends the ARM7TDMI core with an MMU and a few other goodies.

|> Doing an ELF kernel shouldn't be too bad as I believe that arm26 is an ELF
|> kernel, so we do have ELF arm stuff around, however we're still not that
|> close to doing full blown ELF on arm32, it would probably take some kind of
|> cross compiler for the kernel. And some of the asm files would need a bit of
|> work to cope with ELF.
|They _should_ all be correct.  Certainly it's possible to compile
|NetBSD/arm32 ELF kernels, and BtNetBSD should be able to boot them.
|Reinoud vanished before he tested my last round of fixes though.

I have gcc cross compilers for ARM built and running on FreeBSD.  One
set is based upon 2.8.1 with COFF and the other is GCC 2.95.2 with ELF.
Will either of these be usable?  If not, what should I build?

What cross tools besides gcc will I need to build into order to be
able to compile a kernel?

TJ Merritt