[U-Boot] ARM CONFIG_OF_CONTROL status

[Stephan Linz <linz@li-pro.net>]

Am Dienstag, den 03.07.2012, 12:21 -0700 schrieb Simon Glass: 
> Hi,
> 
> On Sun, Jul 1, 2012 at 10:43 PM, Michal Simek <monstr@monstr.eu> wrote:
> 
> > 2012/6/29 Stephan Linz <linz@li-pro.net>:
> > > Am Freitag, den 29.06.2012, 10:18 +0200 schrieb Michal Simek:
> > >> On 06/29/2012 04:32 AM, Simon Glass wrote:
> > >> > Hi,
> > >> >
> > >> > --snip--
> > >>
> > >> I have sent support for Microblaze. Currently without dts because I
> > want to clear this part a little bit.
> > >
> > > Hi Michal,
> > >
> > > looks good, I've been waiting a long time on the FDT support in U-Boot
> > > for Microblaze -- great -- PS: see my comment on patch 5 ...
> > >
> > >>
> > >> Tegra is using ./arch/arm/dts/tegra20.dtsi and
> > board/nvidia/dts/tegra2-seaboard.dts
> > >> and they are composed together in dts/Makefile by calling preprocessor.
> > >> Microblaze will be totally different case because every Microblaze hw
> > design is different.
> > >
> > > Yes, that's right. We will never be in the position to define a skeleton
> > > or a basic platform configuration.
> > >
> > >> We can use two main buses (little and big endian) and cpu is also
> > configurable.
> > >> Based on this for Microblaze is the best solution directly to use dts.
> > >> (DTS for Microblaze is also generated directly from design tool).
> > >
> > > ... directly in the context of a board, not arch/cpu, right?
> >
> > yes.
> >
> > >
> > >>
> > >>
> > >> Anyway - here is the bug message I am getting if I use full dts in
> > board/<name>/dts/microblaze.dts
> > >> and empty arch/microblaze/dts/microblaze.dtsi
> > >>
> > >> <stdin>:34:3: error: invalid preprocessing directive #address
> > >> <stdin>:35:3: error: invalid preprocessing directive #size
> > >> <stdin>:52:4: error: invalid preprocessing directive #address
> > >> <stdin>:53:4: error: invalid preprocessing directive #cpus
> > >> <stdin>:54:4: error: invalid preprocessing directive #size
> > >> <stdin>:155:4: error: invalid preprocessing directive #address
> > >> <stdin>:156:4: error: invalid preprocessing directive #size
> > >> <stdin>:160:5: error: invalid preprocessing directive #gpio
> > >> <stdin>:192:5: error: invalid preprocessing directive #gpio
> > >> <stdin>:209:5: error: invalid preprocessing directive #gpio
> > >> <stdin>:241:5: error: invalid preprocessing directive #gpio
> > >> <stdin>:267:5: error: invalid preprocessing directive #address
> > >> <stdin>:268:5: error: invalid preprocessing directive #size
> > >> <stdin>:394:5: error: invalid preprocessing directive #interrupt
> > >>
> > >> This is error for opposite case - empty microblaze.dts and full
> > microblaze.dtsi.
> > >
> > > That are CPP errors, because the auto generated xilinx.dts is full of
> > > CPP pragma like syntax (#something) that are wrong (invalid).
> >
> > I know what it is.
> >
> > >
> > >>
> > >> make[1]: Entering directory `/mnt/projects/u-boot/dts'
> > >> rc=$( cat /mnt/projects/u-boot/board/petalogix/dts/microblaze.dts |
> > microblaze-unknown-linux-gnu-gcc -E
> > >> -P
> > -DARCH_CPU_DTS=\"/mnt/projects/u-boot/arch/microblaze/dts/microblaze.dtsi\"
> > - | { { dtc -R 4 -p 0x1000
> > >> -O dtb -o dt.dtb - 2>&1 ; echo $? >&3 ; } | grep -v '^DTC: dts->dtb  on
> > file' ; } 3>&1 ) ; \
> > >>       exit $rc
> > >> /bin/sh: line 1: exit: too many arguments
> > >> make[1]: *** [dt.dtb] Error 1
> > >> make[1]: Leaving directory `/mnt/projects/u-boot/dts'
> > >>
> > >>
> > >> I have just tried to fix it by introducing new CONFIG option for
> > skipping that preprocessor
> > >> part.
> > >
> > > Instead of disable / skipp the CPP step you can hide the auto generated
> > > xilinx.dts with a second include stage, for example:
> > >
> > > board/microblaze/dts/microblaze.dts looks like:
> > >
> > > /include/ ARCH_CPU_DTS
> > > /include/ BOARD_DTS
> > >
> > >
> > > Right, only two lines.   The arch/microblaze/dts/microblaze.dtsi remains
> > > empty as you have said above. Just new is BOARD_DTS -- with the attached
> > > patch for dts/Makefile you can copy the auto generated xilinx.dts into
> > > the specific board directory and the CPP step substitute the right place
> > > to board/microblaze/microblaze-generic/dts/microblaze.dts
> > >
> > > I think there are no side effects with other ports like the tegra2.
> > >
> > > If you want you can omit the ARCH_CPU_DTS inclusion. The architectural
> > > microblaze.dtsi file is empty and (!!) have to be empty, because the DTC
> > > will break with an error on multiple "/dts-v1/;" lines!
> > >
> > > Here is the patch:
> > >
> > > diff --git a/dts/Makefile b/dts/Makefile
> > > index 914e479..b1f47a1 100644
> > > --- a/dts/Makefile
> > > +++ b/dts/Makefile
> > > @@ -36,7 +36,8 @@ $(error Your architecture does not have device tree
> > > support enabled. \
> > > Please define CONFIG_ARCH_DEVICE_TREE))
> > >
> > > # We preprocess the device tree file provide a useful define
> > > -DTS_CPPFLAGS := -DARCH_CPU_DTS=
> > > \"$(SRCTREE)/arch/$(ARCH)/dts/$(CONFIG_ARCH_DEVICE_TREE).dtsi\"
> > > +DTS_CPPFLAGS := -DARCH_CPU_DTS=
> > > \"$(SRCTREE)/arch/$(ARCH)/dts/$(CONFIG_ARCH_DEVICE_TREE).dtsi\" \
> > > +               -DBOARD_DTS=
> > > \"$(SRCTREE)/board/$(VENDOR)/$(BOARD)/dts/$(DEVICE_TREE).dts\"
> > >
> > > all:   $(obj).depend $(LIB)
> >
> > Not sure if using another dts file will be the best approach.
> > From my point of view will be the best to support only one dts file
> > (without dtsi)
> > because it is much cleaner then using 3 dts files.
> >
> 
> Well there is no inherent problem with having multiple include files,
> except that it is hard to support with the old dtc when there are in
> different subdirs.
> 
> As a workaround, how about putting the include files in the
> board/vendor/dts subdir as well for now?

Hi,

good idea -- but they cannot be used directly. The substitution variable
ARCH_CPU_DTS is already reserved for dtsi in arch/cpu. The Microblaze
architecture needs a board specific dts onyl. That's why I think the new
substitution variable BOARD_DTS can be a option to solve the CPP problem
today and handle the dtc -i in the future.

BOARD_DTS can point to anything below board/vendor and perhaps with a
new configuration option similar to CONFIG_DEFAULT_DEVICE_TREE the
substitution could be affected with freely selectable file name instead
of DEVICE_TREE only.


br,
Stephan


> 
> Regards,
> Simon
> 
> 
> >
> > Thanks,
> > Michal
> >
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