Device tree for powerpc boards.

Device tree for powerpc boards.

[Leonid]

Hi:

I am using u-boot (1.3.0.rc3) and Linux (2.6.23) on Frescale MPC8544DS
board. This is my first exposure to the powerpc architecture (used to be
ppc in old days), so I have been reading all available manuals I could
find on the subject.=20

I think I do understand the picture but need some minor clarifications.

1) Is the usage of device tree absolutely mandatory for powerpc boards
or just recommended and by combining appropriate defines in u-boot and
linux it can be avoided?=20

2) I understood that I can add my proprietary drivers without creating
nodes for them in the tree, is it correct?

3) In order to compile DT blob from DT source, DT compiler (dtc) is
required. I have installed one on my ubuntu machine and successfully
compiled source, creating a blob. Is this the only way to go? Perhaps
there is some target in Linux or u-boot Makefiles which does this job?=20

Thanks,

Leonid.

Re: Device tree for powerpc boards.

[Jon Loeliger]

Leonid wrote:
> Hi:

Hi.

> 1) Is the usage of device tree absolutely mandatory for powerpc boards
> or just recommended and by combining appropriate defines in u-boot and
> linux it can be avoided? 

Consider it mandatory.

> 2) I understood that I can add my proprietary drivers without creating
> nodes for them in the tree, is it correct?

Maybe, maybe not.  Device Trees describe _hardware_, not drivers.

> 3) In order to compile DT blob from DT source, DT compiler (dtc) is
> required. I have installed one on my ubuntu machine and successfully
> compiled source, creating a blob. Is this the only way to go? Perhaps
> there is some target in Linux or u-boot Makefiles which does this job? 

Install the DTC anyway you want.  I recommend grabbing
it from jdl.com and building it.

jdl

RE: Device tree for powerpc boards.

[Leonid]

Hi, Jon:

Thanks a lot for your explanation.

Leonid.=20

-----Original Message-----
From: Jon Loeliger [mailto:jdl@freescale.com]=20
Sent: Friday, June 13, 2008 10:50 AM
To: Leonid
Cc: linuxppc-embedded@ozlabs.org
Subject: Re: Device tree for powerpc boards.

Leonid wrote:
> Hi:

Hi.

> 1) Is the usage of device tree absolutely mandatory for powerpc boards

> or just recommended and by combining appropriate defines in u-boot and

> linux it can be avoided?

Consider it mandatory.

> 2) I understood that I can add my proprietary drivers without creating

> nodes for them in the tree, is it correct?

Maybe, maybe not.  Device Trees describe _hardware_, not drivers.

> 3) In order to compile DT blob from DT source, DT compiler (dtc) is=20
> required. I have installed one on my ubuntu machine and successfully=20
> compiled source, creating a blob. Is this the only way to go? Perhaps=20
> there is some target in Linux or u-boot Makefiles which does this job?

Install the DTC anyway you want.  I recommend grabbing it from jdl.com
and building it.

jdl