Subject: Re: [RFC] Device tree for new desktop platform in arch/powerpc

From: "Gerhard Pircher" <[email-masked]>
Date: Tue, 19 Jun 2007 11:08:16 +0200

-------- Original-Nachricht --------
Datum: Tue, 19 Jun 2007 08:08:42 +0200
Von: Segher Boessenkool <[email-masked]>
An: "Gerhard Pircher" <[email-masked]>
CC: ppcdev list <[email-masked]>
Betreff: Re: [RFC] Device tree for new desktop platform in arch/powerpc

> Just name the cpu nodes "cpu@0" etc.  The "generic names"
> recommended practice wants this, and the node names here
> aren't actually used by anything anyway, except they look
> nice to the user.  The PowerPC ISA binding predates the
> generic names r.p. btw.
Good! That simplifies the (yet to be written) amigaone-cuboot.c
bootwrapper code a lot.

> > 3. The dts files define the device_type of a serial port as "serial", 
> > whereas the OF spec says "pnpPNP,501". What's the difference between 
> > the two?
> 
> "device_type" is "serial", "compatible" is "pnpPNP,whatever".
Sorry, I was thinking about compatible = "ns16550" and
compatible = "pnp..", but wrote device_type = "serial".
What's the difference between "ns16550" and "pnpPNP,501"?

> Where in the OF specs did you find this pnpPNP thing btw?
See here:
http://playground.sun.com/1275/bindings/devices/html/serial.html

or

Quote from the document:
>  "compatible" S
> Standard property name, specifies device names with which this
> device is compatible.
> 
> The meaning of this property is as defined in Open Firmware,
> as modified by the Generic Names Recommended Practice [7]. As
> described in those documents, the entries are a list of device
> names with which this device is compatible, starting with the
> name of the device itself and progressing through successively
> less precise and possibly less functional compatible devices.
> 
> For this device, the compatible property shall include "pnpPNP,501."
- End -

> "name" = "device_type" = "interrupt-controller".
> "compatible" is one of those pnpPNP things.

Quote from the "CHRP(TM) ISA Interrupt Controller Device
Binding" document:
> "compatible" S
> Standard property name, specifies device names with which
> this device is compatible.
> ....
> The compatible property shall include "chrp,iic."
- End -

I couldn't find any reference about a "pnp..." value for an i8259
interrupt controller. Is there already a generic function within the
kernel that can setup the interrupt controller based solely on the
information in the device tree?

> Please send the thing inline, not as an attachment.
Okay, will do so next time.

Thanks!

regards,

Gerhard
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