On Mon, Jun 09, 2025 at 01:56:26PM +0530, Anshul Dalal wrote: > On Tue Jun 3, 2025 at 10:36 PM IST, Eric Schikschneit wrote: > > This will allow arch(s) that use device tree blobs to pad the end of the > > device tree so they can be modified by board files at run time. This will > > help prevent errors such as FDT_ERR_NOSPACE from occuring. > > > > Signed-off-by: Eric Schikschneit <eric.schikschn...@novatechautomation.com> > > --- > > arch/Kconfig | 7 +++++++ > > arch/arc/dts/Makefile | 2 +- > > arch/m68k/dts/Makefile | 2 +- > > arch/microblaze/dts/Makefile | 2 +- > > arch/nios2/dts/Makefile | 2 +- > > arch/riscv/dts/Makefile | 2 +- > > arch/sandbox/dts/Makefile | 2 +- > > arch/x86/dts/Makefile | 2 +- > > doc/board/broadcom/bcm7xxx.rst | 6 ++---- > > doc/develop/makefiles.rst | 5 ++++- > > dts/upstream/src/arm64/Makefile | 2 +- > > dts/upstream/src/riscv/Makefile | 2 +- > > scripts/Makefile.dts | 4 ++++ > > 13 files changed, 26 insertions(+), 14 deletions(-) > > > > diff --git a/arch/Kconfig b/arch/Kconfig > > index ea33d07c086..bf4c2c80891 100644 > > --- a/arch/Kconfig > > +++ b/arch/Kconfig > > @@ -63,6 +63,13 @@ config SYS_CACHELINE_SIZE > > default 64 if RISCV > > default 32 if MIPS > > > > +config SYS_DTC_PAD_BYTES > > + int "Size in bytes to pad device tree blob" > > + default 4096 if ARC || ARM64 || M68K || MICROBLAZE || NIOS2 \ > > + || RISCV || SANDBOX || X86 > > + default 32768 if X86 && EFI_APP > > + default 0 > > + > > config LINKER_LIST_ALIGN > > int > > default 32 if SANDBOX > > diff --git a/arch/arc/dts/Makefile b/arch/arc/dts/Makefile > > index fe6ad7b849a..87c627c01c8 100644 > > --- a/arch/arc/dts/Makefile > > +++ b/arch/arc/dts/Makefile > > @@ -11,4 +11,4 @@ dtb-$(CONFIG_TARGET_IOT_DEVKIT) += iot_devkit.dtb > > include $(srctree)/scripts/Makefile.dts > > > > # Add any required device tree compiler flags here > > -DTC_FLAGS += -R 4 -p 0x1000 > > +DTC_FLAGS += -R 4 > > Thanks for the patch Eric, the changes to padding size look good to me > although I wonder if we should expose the -R flag for configuring the > number of /reserved-memory to user under Kconfig as well. > > We have it hardcoded to 4 everywhere now, might be useful to expose it > as CONFIG_SYS_DTC_RSVD or similar for users looking to create compact > DTBs (-R 0) or where more reserved regions need to be added at runtime.
That could be an interesting follow-up patch, yes. -- Tom
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