Hi Frank,

On 15/12/17 22:06, Frank Rowand wrote:

On 12/14/17 07:12, Andre Heider wrote:

quoted

The overlay feature requires the base dtb to be built with symbols, so
lets build the dtbs with symbols when overlay support was explicitly
enabled.

With CONFIG_OF_ALL_DTBS on ARCH=arm the 989 dtb files grow about ~38% on
average.

Totals in bytes with the 3 biggest ones:

Before:
	90471	arch/arm/boot/dts/am57xx-beagle-x15-revc.dtb
	90521	arch/arm/boot/dts/am57xx-beagle-x15-revb1.dtb
	92639	arch/arm/boot/dts/dra7-evm.dtb
	25731296	total

After:
	133203	arch/arm/boot/dts/am57xx-beagle-x15-revc.dtb
	133237	arch/arm/boot/dts/am57xx-beagle-x15-revb1.dtb
	134545	arch/arm/boot/dts/dra7-evm.dtb
	35464440	total

Signed-off-by: Andre Heider <redacted>
---

Hi,

while playing around with overlays I noticed that I needed to rebuilt
my distro's device trees because they didn't come with symbols.

Is that for a reason, maybe the not so minor increase in size?

Yes, size is the issue.

quoted

Thanks,
Andre

  drivers/of/unittest-data/Makefile | 7 -------
  scripts/Makefile.lib              | 5 +++++
  2 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/of/unittest-data/Makefile b/drivers/of/unittest-data/Makefile
index 32389acfa616..b65061013512 100644
--- a/drivers/of/unittest-data/Makefile
+++ b/drivers/of/unittest-data/Makefile

@@ -15,13 +15,6 @@ targets += overlay.dtb overlay.dtb.S
  targets += overlay_bad_phandle.dtb overlay_bad_phandle.dtb.S
  targets += overlay_bad_symbol.dtb overlay_bad_symbol.dtb.S
  targets += overlay_base.dtb overlay_base.dtb.S
-
-# enable creation of __symbols__ node
-DTC_FLAGS_overlay := -@
-DTC_FLAGS_overlay_bad_phandle := -@
-DTC_FLAGS_overlay_bad_symbol := -@
-DTC_FLAGS_overlay_base := -@
-
  endif
  
  .PRECIOUS: \

No.  The unittests require these to be set unconditionally.

quoted

diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 1ca4dcd2d500..c7ba4aa8a07a 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib

@@ -278,6 +278,11 @@ DTC_FLAGS += -Wnode_name_chars_strict \
  	-Wproperty_name_chars_strict
  endif
  
+ifeq ($(CONFIG_OF_OVERLAY),y)
+# enable creation of __symbols__ node
+DTC_FLAGS += -@
+endif
+
  DTC_FLAGS += $(DTC_FLAGS_$(basetarget))
  
  # Generate an assembly file to wrap the output of the device tree compiler

Not needed.  Instead set DTC_FLAGS in the make command.  For example:

    DTC_FLAGS=-@ make qcom-apq8074-dragonboard.dtb

There are a few architecture Makefiles that need to be fixed to not unconditionally
set DTC_FLAGS.

Rebuilding the dts files manually with symbols isn't the problem. The 
idea was to enable it with a switch which distros simply can flip.

Passing DTC_FLAGS to `make` would work too I guess, but on multi 
platform builds that's still the same issue if there're boards which 
can't handle that because of the size increase.

Would a solution which enables symbols per family work?
E.g. CONFIG_MACH_SUN7I chooses to use -@ because it can handle it.

Thanks,
Andre