Documentation: kbuild: Remove obsolete dtc_cpp section

Commit b40b25fff8 ("kbuild: always
run gcc -E on *.dts, remove cmd_dtc_cpp") improved the functionality of
cmd_dtc_cpp and merged it back into cmd_dtc.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
This commit is contained in:
Geert Uytterhoeven 2014-08-08 17:23:09 +02:00 committed by Michal Marek
parent ef80f0a1e0
commit cf6c53db95

View File

@ -1163,29 +1163,6 @@ When kbuild executes, the following steps are followed (roughly):
clean-files += *.dtb clean-files += *.dtb
DTC_FLAGS ?= -p 1024 DTC_FLAGS ?= -p 1024
dtc_cpp
This is just like dtc as describe above, except that the C pre-
processor is invoked upon the .dtsp file before compiling the result
with dtc.
In order for build dependencies to work, all files compiled using
dtc_cpp must use the C pre-processor's #include functionality and not
dtc's /include/ functionality.
Using the C pre-processor allows use of #define to create named
constants. In turn, the #defines will typically appear in a header
file, which may be shared with regular C code. Since the dtc language
represents a data structure rather than code in C syntax, similar
restrictions are placed on a header file included by a device tree
file as for a header file included by an assembly language file.
In particular, the C pre-processor is passed -x assembler-with-cpp,
which sets macro __ASSEMBLY__. __DTS__ is also set. These allow header
files to restrict their content to that compatible with device tree
source.
A central rule exists to create $(obj)/%.dtb from $(src)/%.dtsp;
architecture Makefiles do no need to explicitly write out that rule.
--- 6.8 Custom kbuild commands --- 6.8 Custom kbuild commands
When kbuild is executing with KBUILD_VERBOSE=0, then only a shorthand When kbuild is executing with KBUILD_VERBOSE=0, then only a shorthand