Re: FATAL ERROR: Unable to parse input tree

[Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>]

On Tue, Jun 03, 2014 at 03:35:39PM +0100, Pacman du34 wrote:
> 2014-06-03 15:35 GMT+02:00 Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>:
> > On Tue, Jun 03, 2014 at 02:25:25PM +0100, Pacman du34 wrote:
> >> 2014-06-03 15:02 GMT+02:00 Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>:
> >> > On Tue, Jun 03, 2014 at 01:53:24PM +0100, Pacman du34 wrote:
> >> >> Hello all,
> >> >>
> >> >> I am working on a new Linux port to a new architecture and I would like
> >> >> to add a dts file to describe my system.
> >> >>
> >> >> So first of all I wrote the following dts test file :
> >> >>
> >> >> / {
> >> >>     compatible = "manufacturer,cpu";
> >> >> };
> >> >>
> >> >> I've read that this is the minimum structure required for a device tree
> >> >> on the wiki.
> >> >>
> >> >> But when I try compiling it with dtc (the first line is the command
> >> >> line) I get this error message :
> >> >>
> >> >> dtc -I dts -O dtb -o my_file.dtb myfile.dts
> >> >>
> >> >> Error: myfile.dts:1.1-2 syntax error
> >> >> FATAL ERROR: Unable to parse input tree
> >> >
> >> > You're missing the DTS version. Try:
> >> >
> >> > /dts-v1/;
> >> > / {
> >> >         comaptible = "manufacturer,device";
> >> > };
> >> >
> >> > Cheers,
> >> > Mark.
> >> >
> >> >>
> >> >> I tried both the dtc version of Linux source code (1.2.0-g37c0b6a0) and
> >> >> dtc version installed with "apt-get install device-tree-compiler" (1.3.0).
> >> >>
> >> >> I searched on Google but I have not found relevant information for my issue.
> >> >>
> >> >> I really do not understand what the problem here and I am totally stuck.
> >> >> Any help will be appreciated.
> >> >>
> >> >> Thanks a lot in advance.
> >> >>
> >> >> Best regards.
> >>
> >> That works, thank you very much,
> >>
> >> I take this opportunity to ask another question... As I have to
> >> specify the DTS version, are there other versions, and if yes, what
> >> are their differences ? I mean, if there are other versions, why to
> >> choose the vesion 2 instead of 3 or 1 ?
> >
> > There was a v0 a while back according to ePAPR, but it's obsolete,
> > incompatible and no-one uses it anymore (dtc doesn't support it as far
> > as I can tell). The flag is to tell v1 apart from v0.
> >
> > There is not currently a v2 or later. Perhaps there might be in future,
> > so it's worth keeping the flag around, but at present there's
> > effectively only v1.
> >
> > Cheers,
> > Mark.
> 
> Ok thank you very much again for your quick answer.
> 
> So I'll keep using v1 flag.
> 
> At the beginning of the porting, I was using a kernel version which
> does not support Device Tree, I only had a C file to initialize the
> drivers for my board. And I'm trying to understand how to add the
> support of Device Tree to the kernel. Because now I have a dtb file,
> but no message appears during the boot, showing that the kernel knows
> it must read this file and use the matching device drivers.
> 
> I have seen that some manufacturers use "config USE_OF", in the
> Kconfig file, to give the option to add device tree support when
> compiling the kernel. So I added the same option, but I don't know how
> to confirm that the kernel is now using device tree.
> 
> Will it appear some messages, during boot, that indicate the kernel is
> really using it ?

That would all be up to your architecture code. I'm afraid I can't
really help with debugging architectural bringup.

I can only recommend that you look through what other architectures do
as part of their boot sequence, and do something along those lines.

Cheers,
Mark.
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