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 <[email protected]>
---
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?
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: \
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
--
2.15.1
On 12/14/17 07:12, Andre Heider wrote:
> 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 <[email protected]>
> ---
>
> 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.
>
> 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.
> 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.
-Frank
Hi Frank,
On 15/12/17 22:06, Frank Rowand wrote:
> On 12/14/17 07:12, Andre Heider wrote:
>> 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 <[email protected]>
>> ---
>>
>> 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.
>
>
>>
>> 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.
>
>
>> 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
On 12/16/17 09:25, Andre Heider wrote:
> Hi Frank,
>
> On 15/12/17 22:06, Frank Rowand wrote:
>> On 12/14/17 07:12, Andre Heider wrote:
>>> 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 <[email protected]>
>>> ---
>>>
>>> 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.
>>
>>
>>>
>>> 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.
>>
>>
>>> 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
Making it easy for distros to increase the size of .dtb files is
not the correct answer. We are trying to decrease the footprint
of devicetree, not increase it.
-Frank
On 18/12/17 23:10, Frank Rowand wrote:
> On 12/16/17 09:25, Andre Heider wrote:
>> Hi Frank,
>>
>> On 15/12/17 22:06, Frank Rowand wrote:
>>> On 12/14/17 07:12, Andre Heider wrote:
>>>> 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 <[email protected]>
>>>> ---
>>>>
>>>> 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.
>>>
>>>
>>>>
>>>> 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.
>>>
>>>
>>>> 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
>
> Making it easy for distros to increase the size of .dtb files is
> not the correct answer. We are trying to decrease the footprint
> of devicetree, not increase it.
I'm not sure I follow. If it's not acceptable to increase the size,
why's there overlay support in the first place?
There're distros/downstreams that support overlays today, like armbian,
beaglebone and rpi. All carrying their own patches to enable symbols [1]
[2] [3] and I'm sure others will follow. Why can't there be some sort of
switch for those to build their dtbs with symbols?
Regards,
Andre
[1]
https://github.com/armbian/build/blob/master/patch/kernel/sunxi-next/add-overlay-compilation-support.patch#L98
[2]
https://github.com/beagleboard/linux/commit/ed6b9450c2a2ec21149f14ff24770b69888abda6
[3]
https://github.com/raspberrypi/linux/blob/rpi-4.15.y/arch/arm/boot/dts/Makefile#L1124