Cmdline FDT query tool

Cmdline FDT query tool

[John Williams]

Hi Grant,

At ELC I mentioned a tool I'd written that basically hacked u-boot's
"fdt" command into a commandline util for querying DTBs.  You can do
stuff like this:

$ fdt-tool system.dtp print

<dump entire DTB in text format>

$ fdt-tool system.dtb list /cpus/cpu@0 xlnx,use-dcache
xlnx,use-dcache = <0x1>

and so on.

I wrote it four our PetaLinux distribution because we need our tools
to make decisions based on contents of device trees, but thought you
might like to look at it, see if it's more broadly useful (maybe could
be a candidate for scripts/ in the kernel for example).

It's pretty rough, I hacked it together in about 20 minutes and threw
in a readline interface so you can also use it interactively as well.

Possible enhancements would be
  * clean up!
  * support DTS input format (only DTB supported currently)
  * Allow modifying and re-writing (current DTB is read-only)

It can also do some interesting things with u-boot FIT images - you
can basically crack out kernel, DTB or rootfs payloads from a FIT.

If it does go into the kernel then MicroBlaze arch would be an
immediate user, we have a few KCONFIG params that drive GCC cpuflag
options - for simpleImage targets we could pull these straight from
the DTS instead to avoid kernel/CPU mismatches.  We could do it today
with sed/grep/awk etc, but it's ugly ugly ugly.  A DTS-aware tool like
this would make it a no-brainer.  I'm sure PPC could find some useful
things to do with it as well.

http://developer.petalogix.com/downloads/fdt-tool.tar.gz

Cheers,

John
-- 
John Williams, PhD, B.Eng, B.IT
PetaLogix - Linux Solutions for a Reconfigurable World
w: www.petalogix.com  p: +61-7-30090663  f: +61-7-30090663

Re: Cmdline FDT query tool

[David Gibson]

On Tue, May 18, 2010 at 12:03:19PM +1000, John Williams wrote:
> Hi Grant,
> 
> At ELC I mentioned a tool I'd written that basically hacked u-boot's
> "fdt" command into a commandline util for querying DTBs.  You can do
> stuff like this:
> 
> $ fdt-tool system.dtp print
> 
> <dump entire DTB in text format>
> 
> $ fdt-tool system.dtb list /cpus/cpu@0 xlnx,use-dcache
> xlnx,use-dcache = <0x1>
> 
> and so on.
> 
> I wrote it four our PetaLinux distribution because we need our tools
> to make decisions based on contents of device trees, but thought you
> might like to look at it, see if it's more broadly useful (maybe could
> be a candidate for scripts/ in the kernel for example).
> 
> It's pretty rough, I hacked it together in about 20 minutes and threw
> in a readline interface so you can also use it interactively as well.

Interesting.  It might be nice to include this into the libfdt tree,
as both a code example and a useful standalone tool.

> Possible enhancements would be
>   * clean up!
>   * support DTS input format (only DTB supported currently)

Hrm.  Unless you do it by calling out to dtc, that would be a big job,
and essentially mean re-implementing a big chunk of dtc - with which
it could then get out of sync.  So please don't do that.

>   * Allow modifying and re-writing (current DTB is read-only)
> 
> It can also do some interesting things with u-boot FIT images - you
> can basically crack out kernel, DTB or rootfs payloads from a FIT.
> 
> If it does go into the kernel then MicroBlaze arch would be an
> immediate user, we have a few KCONFIG params that drive GCC cpuflag
> options - for simpleImage targets we could pull these straight from
> the DTS instead to avoid kernel/CPU mismatches.  We could do it today
> with sed/grep/awk etc, but it's ugly ugly ugly.  A DTS-aware tool like
> this would make it a no-brainer.  I'm sure PPC could find some useful
> things to do with it as well.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

Re: Cmdline FDT query tool

[Grant Likely]

On Mon, May 17, 2010 at 8:03 PM, John Williams
<john.williams-g5w7nrANp4BDPfheJLI6IQ@public.gmane.org> wrote:
> Hi Grant,
>
> At ELC I mentioned a tool I'd written that basically hacked u-boot's
> "fdt" command into a commandline util for querying DTBs.  You can do
> stuff like this:
>
> $ fdt-tool system.dtp print
>
> <dump entire DTB in text format>
>
> $ fdt-tool system.dtb list /cpus/cpu@0 xlnx,use-dcache
> xlnx,use-dcache = <0x1>
>
> and so on.

Cool.  Thanks John.

I agree with David.  It would probably be useful to include in the
libfdt (which U-Boot fdt support makes use of too) source repo.  Seems
like a useful tool.

Cheers,
g.

Re: Cmdline FDT query tool

[David Gibson]

On Tue, May 18, 2010 at 12:20:05PM -0600, Grant Likely wrote:
> On Mon, May 17, 2010 at 8:03 PM, John Williams
> <john.williams-g5w7nrANp4BDPfheJLI6IQ@public.gmane.org> wrote:
> > Hi Grant,
> >
> > At ELC I mentioned a tool I'd written that basically hacked u-boot's
> > "fdt" command into a commandline util for querying DTBs.  You can do
> > stuff like this:
> >
> > $ fdt-tool system.dtp print
> >
> > <dump entire DTB in text format>
> >
> > $ fdt-tool system.dtb list /cpus/cpu@0 xlnx,use-dcache
> > xlnx,use-dcache = <0x1>
> >
> > and so on.
> 
> Cool.  Thanks John.
> 
> I agree with David.  It would probably be useful to include in the
> libfdt (which U-Boot fdt support makes use of too) source repo.  Seems
> like a useful tool.

Of course, to incorporate it with libfdt, it would need to be BSD
dual-licensed, like the rest of libfdt, and we'd need sign-offs from
all authors to that effect.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

Re: Cmdline FDT query tool

[John Williams]

On Sat, May 22, 2010 at 10:17 AM, David Gibson
<david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org> wrote:
> On Tue, May 18, 2010 at 12:20:05PM -0600, Grant Likely wrote:
>> On Mon, May 17, 2010 at 8:03 PM, John Williams
>> <john.williams-g5w7nrANp4BDPfheJLI6IQ@public.gmane.org> wrote:
>> > Hi Grant,
>> >
>> > At ELC I mentioned a tool I'd written that basically hacked u-boot's
>> > "fdt" command into a commandline util for querying DTBs.  You can do
>> > stuff like this:
>> >
>> > $ fdt-tool system.dtp print
>> >
>> > <dump entire DTB in text format>
>> >
>> > $ fdt-tool system.dtb list /cpus/cpu@0 xlnx,use-dcache
>> > xlnx,use-dcache = <0x1>
>> >
>> > and so on.
>>
>> Cool.  Thanks John.
>>
>> I agree with David.  It would probably be useful to include in the
>> libfdt (which U-Boot fdt support makes use of too) source repo.  Seems
>> like a useful tool.
>
> Of course, to incorporate it with libfdt, it would need to be BSD
> dual-licensed, like the rest of libfdt, and we'd need sign-offs from
> all authors to that effect.

I have no problem with that, but since I ripped the guts of it
directly from u-boot there'll be a conversation to be had there.

John

Re: Cmdline FDT query tool

[David Gibson]

On Thu, May 27, 2010 at 11:40:51AM +1000, John Williams wrote:
> On Sat, May 22, 2010 at 10:17 AM, David Gibson
> <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org> wrote:
> > On Tue, May 18, 2010 at 12:20:05PM -0600, Grant Likely wrote:
> >> On Mon, May 17, 2010 at 8:03 PM, John Williams
> >> <john.williams-g5w7nrANp4BDPfheJLI6IQ@public.gmane.org> wrote:
> >> > Hi Grant,
> >> >
> >> > At ELC I mentioned a tool I'd written that basically hacked u-boot's
> >> > "fdt" command into a commandline util for querying DTBs.  You can do
> >> > stuff like this:
> >> >
> >> > $ fdt-tool system.dtp print
> >> >
> >> > <dump entire DTB in text format>
> >> >
> >> > $ fdt-tool system.dtb list /cpus/cpu@0 xlnx,use-dcache
> >> > xlnx,use-dcache = <0x1>
> >> >
> >> > and so on.
> >>
> >> Cool.  Thanks John.
> >>
> >> I agree with David.  It would probably be useful to include in the
> >> libfdt (which U-Boot fdt support makes use of too) source repo.  Seems
> >> like a useful tool.
> >
> > Of course, to incorporate it with libfdt, it would need to be BSD
> > dual-licensed, like the rest of libfdt, and we'd need sign-offs from
> > all authors to that effect.
> 
> I have no problem with that, but since I ripped the guts of it
> directly from u-boot there'll be a conversation to be had there.

Ok.  Do you have the means to track down the people with whom this
conversation needs to happen?

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

Re: Cmdline FDT query tool

[John Williams]

On Thu, May 27, 2010 at 3:17 PM, David Gibson
<david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org> wrote:
> On Thu, May 27, 2010 at 11:40:51AM +1000, John Williams wrote:
>> On Sat, May 22, 2010 at 10:17 AM, David Gibson
>> <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org> wrote:
>> > On Tue, May 18, 2010 at 12:20:05PM -0600, Grant Likely wrote:
>> >> On Mon, May 17, 2010 at 8:03 PM, John Williams
>> >> <john.williams-g5w7nrANp4BDPfheJLI6IQ@public.gmane.org> wrote:
>> >> > Hi Grant,
>> >> >
>> >> > At ELC I mentioned a tool I'd written that basically hacked u-boot's
>> >> > "fdt" command into a commandline util for querying DTBs.  You can do
>> >> > stuff like this:
>> >> >
>> >> > $ fdt-tool system.dtp print
>> >> >
>> >> > <dump entire DTB in text format>
>> >> >
>> >> > $ fdt-tool system.dtb list /cpus/cpu@0 xlnx,use-dcache
>> >> > xlnx,use-dcache = <0x1>
>> >> >
>> >> > and so on.
>> >>
>> >> Cool.  Thanks John.
>> >>
>> >> I agree with David.  It would probably be useful to include in the
>> >> libfdt (which U-Boot fdt support makes use of too) source repo.  Seems
>> >> like a useful tool.
>> >
>> > Of course, to incorporate it with libfdt, it would need to be BSD
>> > dual-licensed, like the rest of libfdt, and we'd need sign-offs from
>> > all authors to that effect.
>>
>> I have no problem with that, but since I ripped the guts of it
>> directly from u-boot there'll be a conversation to be had there.
>
> Ok.  Do you have the means to track down the people with whom this
> conversation needs to happen?

>From the header comments:

 * Gerald Van Baren, Custom IDEAS, vanbaren-He//nVnquyzQT0dZR+AlfA@public.gmane.org
 * Based on code written by:
 *   Pantelis Antoniou <pantelis.antoniou-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> and
 *   Matthew McClintock <msm-KZfg59tc24xl57MIdRCFDg@public.gmane.org>

John
-- 
John Williams, PhD, B.Eng, B.IT
PetaLogix - Linux Solutions for a Reconfigurable World
w: www.petalogix.com  p: +61-7-30090663  f: +61-7-30090663

Re: Cmdline FDT query tool

[David Gibson]

On Thu, May 27, 2010 at 03:35:15PM +1000, John Williams wrote:
> On Thu, May 27, 2010 at 3:17 PM, David Gibson
> <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org> wrote:
> > On Thu, May 27, 2010 at 11:40:51AM +1000, John Williams wrote:
> >> On Sat, May 22, 2010 at 10:17 AM, David Gibson
> >> <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org> wrote:
> >> > On Tue, May 18, 2010 at 12:20:05PM -0600, Grant Likely wrote:
> >> >> On Mon, May 17, 2010 at 8:03 PM, John Williams
> >> >> <john.williams-g5w7nrANp4BDPfheJLI6IQ@public.gmane.org> wrote:
> >> >> > Hi Grant,
> >> >> >
> >> >> > At ELC I mentioned a tool I'd written that basically hacked u-boot's
> >> >> > "fdt" command into a commandline util for querying DTBs.  You can do
> >> >> > stuff like this:
> >> >> >
> >> >> > $ fdt-tool system.dtp print
> >> >> >
> >> >> > <dump entire DTB in text format>
> >> >> >
> >> >> > $ fdt-tool system.dtb list /cpus/cpu@0 xlnx,use-dcache
> >> >> > xlnx,use-dcache = <0x1>
> >> >> >
> >> >> > and so on.
> >> >>
> >> >> Cool.  Thanks John.
> >> >>
> >> >> I agree with David.  It would probably be useful to include in the
> >> >> libfdt (which U-Boot fdt support makes use of too) source repo.  Seems
> >> >> like a useful tool.
> >> >
> >> > Of course, to incorporate it with libfdt, it would need to be BSD
> >> > dual-licensed, like the rest of libfdt, and we'd need sign-offs from
> >> > all authors to that effect.
> >>
> >> I have no problem with that, but since I ripped the guts of it
> >> directly from u-boot there'll be a conversation to be had there.
> >
> > Ok.  Do you have the means to track down the people with whom this
> > conversation needs to happen?
> 
> >From the header comments:
> 
>  * Gerald Van Baren, Custom IDEAS, vanbaren-He//nVnquyzQT0dZR+AlfA@public.gmane.org
>  * Based on code written by:
>  *   Pantelis Antoniou <pantelis.antoniou-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> and
>  *   Matthew McClintock <msm-KZfg59tc24xl57MIdRCFDg@public.gmane.org>

Hrm.  People frequently fail to update header comments.  I'd much
rather go off the revision control history, if it's available.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

Re: Cmdline FDT query tool

[John Williams]

On Thu, May 27, 2010 at 4:23 PM, David Gibson
<david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org> wrote:
> On Thu, May 27, 2010 at 03:35:15PM +1000, John Williams wrote:
>> On Thu, May 27, 2010 at 3:17 PM, David Gibson
>> <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org> wrote:
>> > On Thu, May 27, 2010 at 11:40:51AM +1000, John Williams wrote:
>> >> On Sat, May 22, 2010 at 10:17 AM, David Gibson
>> >> <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org> wrote:
>> >> > On Tue, May 18, 2010 at 12:20:05PM -0600, Grant Likely wrote:
>> >> >> On Mon, May 17, 2010 at 8:03 PM, John Williams
>> >> >> <john.williams-g5w7nrANp4BDPfheJLI6IQ@public.gmane.org> wrote:
>> >> >> > Hi Grant,
>> >> >> >
>> >> >> > At ELC I mentioned a tool I'd written that basically hacked u-boot's
>> >> >> > "fdt" command into a commandline util for querying DTBs.  You can do
>> >> >> > stuff like this:
>> >> >> >
>> >> >> > $ fdt-tool system.dtp print
>> >> >> >
>> >> >> > <dump entire DTB in text format>
>> >> >> >
>> >> >> > $ fdt-tool system.dtb list /cpus/cpu@0 xlnx,use-dcache
>> >> >> > xlnx,use-dcache = <0x1>
>> >> >> >
>> >> >> > and so on.
>> >> >>
>> >> >> Cool.  Thanks John.
>> >> >>
>> >> >> I agree with David.  It would probably be useful to include in the
>> >> >> libfdt (which U-Boot fdt support makes use of too) source repo.  Seems
>> >> >> like a useful tool.
>> >> >
>> >> > Of course, to incorporate it with libfdt, it would need to be BSD
>> >> > dual-licensed, like the rest of libfdt, and we'd need sign-offs from
>> >> > all authors to that effect.
>> >>
>> >> I have no problem with that, but since I ripped the guts of it
>> >> directly from u-boot there'll be a conversation to be had there.
>> >
>> > Ok.  Do you have the means to track down the people with whom this
>> > conversation needs to happen?
>>
>> >From the header comments:
>>
>>  * Gerald Van Baren, Custom IDEAS, vanbaren-He//nVnquyzQT0dZR+AlfA@public.gmane.org
>>  * Based on code written by:
>>  *   Pantelis Antoniou <pantelis.antoniou-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> and
>>  *   Matthew McClintock <msm-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
>
> Hrm.  People frequently fail to update header comments.  I'd much
> rather go off the revision control history, if it's available.

Better late than never:

$ git-log --pretty=format:%ae fdt_support.c cmd_fdt.c | sort | uniq

afleming-KZfg59tc24xl57MIdRCFDg@public.gmane.org
agust-ynQEQJNshbs@public.gmane.org
andrew-pwabbKueSRu4mpay0g/RMEEOCMrvLtNR@public.gmane.org
avorontsov-hkdhdckH98+B+jHODAdFcQ@public.gmane.org
dzu-ynQEQJNshbs@public.gmane.org
galak-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org
grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org
gvb.uboot-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
hs-ynQEQJNshbs@public.gmane.org
jacmet-OfajU3CKLf1/SzgSGea1oA@public.gmane.org
ken-VbOJbV3qneKf+c8Povm/Gg@public.gmane.org
kim.phillips-KZfg59tc24xl57MIdRCFDg@public.gmane.org
plagnioj-sclMFOaUSTBWk0Htik3J/w@public.gmane.org
ptyser-AQeFf1F/bRxBDgjK7y7TUQ@public.gmane.org
sr-ynQEQJNshbs@public.gmane.org
timur-KZfg59tc24xl57MIdRCFDg@public.gmane.org
vanbaren-He//nVnquyzQT0dZR+AlfA@public.gmane.org
wd-ynQEQJNshbs@public.gmane.org

Cheers,

John
-- 
John Williams, PhD, B.Eng, B.IT
PetaLogix - Linux Solutions for a Reconfigurable World
w: www.petalogix.com  p: +61-7-30090663  f: +61-7-30090663