[U-Boot] ARM CONFIG_OF_CONTROL status

[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?

> 
> 
> 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).

> 
> 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)


br,
Stephan

> It will be good for Microblaze (probably there is any smarter solution for SKIP case not to have two cats there).
> The same situation will happen for Xilinx ppc support and partially for upcoming ARM zynq where
> full DTS is generated for unique hw design.
> 
> Here is the patch to show you what phase I would like to skip.
> 
> diff --git a/dts/Makefile b/dts/Makefile
> index 914e479..d670cb8 100644
> --- a/dts/Makefile
> +++ b/dts/Makefile
> @@ -45,9 +45,15 @@ all: $(obj).depend $(LIB)
>   # the filename.
>   DT_BIN := $(obj)dt.dtb
> 
> +ifndef CONFIG_DTS_SKIP_PREPROCESSOR
> +SKIP := $(CPP) -P $(DTS_CPPFLAGS) -
> +else
> +SKIP := cat
> +endif
> +
>   $(DT_BIN): $(TOPDIR)/board/$(VENDOR)/dts/$(DEVICE_TREE).dts
>          rc=$$( \
> -               cat $< | $(CPP) -P $(DTS_CPPFLAGS) - | \
> +               cat $< | $(SKIP) |\
>                  { { $(DTC) -R 4 -p 0x1000 -O dtb -o ${DT_BIN} - 2>&1 ; \
>                      echo $$? >&3 ; } | \
>                    grep -v '^DTC: dts->dtb  on file' ; \
> 
> 
> Thanks for your comments.
> Michal
> 


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