Re: Device Tree questions WRT MIPS/Octeon SOCs.

[David Daney <ddaney@caviumnetworks.com>]

On 10/15/2010 10:30 AM, David VomLehn (dvomlehn) wrote:

> If this is really a question of needing to dynamically generate the
> device tree, then you have no choice. It's worth mentioning, though,
> that the device tree compiler (dtc) does have the ability to include
> files, making it easier to create and maintain device trees that are
> static but which share devices.
Some experimentation will be necessary.  We will have to patch in some
properties like the Ethernet MAC address as that is stored in a
separate eeprom.  Also some boards have pluggable I/O modules, so we
may not know at dtb generation time what is there.

David Daney


> > -----Original Message-----
> > From: linux-mips-bounce@linux-mips.org [mailto:linux-mips-bounce@linux-
> > mips.org] On Behalf Of Grant Likely
> > Sent: Thursday, October 14, 2010 6:29 PM
> > To: Warner Losh
> > Cc: ddaney@caviumnetworks.com; prasun.kapoor@caviumnetworks.com; linux-
> > mips@linux-mips.org; devicetree-discuss@lists.ozlabs.org
> > Subject: Re: Device Tree questions WRT MIPS/Octeon SOCs.
> >
> > On Thu, Oct 14, 2010 at 7:13 PM, Warner Losh<imp@bsdimp.com>  wrote:
> > > In message:<AANLkTi=UM2p26JJMqv-
> > cNh8xACS_KPf_dCst5cgmh5VR@mail.gmail.com>
> > >             Grant Likely<grant.likely@secretlab.ca>  writes:
> > > : Overall the plan makes sense, however I would suggest the
> > following.
> > > : instead of 'live' modifying the tree, another option is to carry a
> > set
> > > : of 'stock' device trees in the kernel; one per board.  Of course
> > this
> > > : assumes that your current ad-hoc code is keying on the specific
> > board.
> > > :  If it is interpreting data provided by the firmware, then your
> > > : suggestion of modifying a single stock tree probably makes more
> > sense,
> > > : or possibly a combination of the too.  In general you should avoid
> > > : live modification as much as possible.
> > >
> > > The one draw back on this is that there's lots of different "stock"
> > > boards that the Cavium Octeon SDK supports.  These will be difficult
> > > to drag along for every kernel.  And they'd be mostly the same to,
> > > which is why I think that David is suggesting the live modification
> > > thing...
> > Okay.  Do what makes the most sense for your platform.
> >
> > g.