Up until now when configuring a generic kernel all board config
fragments have been merged by default unless boards are explicitly
selected by the user specifying BOARDS=.
In many cases this is sub-optimal, since some boards don't make sense to
include in some kernels. For example the MIPS SEAD-3 development board
has only ever been used with 32 bit CPUs, so including support for the
SEAD-3 in a 64 bit kernel is wasteful.
This patch introduces support for specifying requirements in board
config fragments, using comments formatted like so:
# require CONFIG_BLA=y
For example the SEAD-3 board could specify that it should only be merged
for 32 bit kernels using a requirement line like the following:
# require CONFIG_32BIT=y
A new generic-board-config.sh script is introduced to handle selecting
the board config fragments to merge & calling merge_config.sh to merge
them. In order to allow requirements to check Kconfig symbols that are
implicitly selected, rather than explicitly specified by
generic_defconfig or one of the ISA config fragments, an intermediate
.config file is saved & used as a reference when checking requirements.
Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
---
MAINTAINERS | 1 +
arch/mips/Makefile | 10 +++-
arch/mips/tools/generic-board-config.sh | 90 +++++++++++++++++++++++++++++++++
3 files changed, 99 insertions(+), 2 deletions(-)
create mode 100755 arch/mips/tools/generic-board-config.sh
diff --git a/MAINTAINERS b/MAINTAINERS
index 44cb004c765d..ca7014a70dd9 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8793,6 +8793,7 @@ M: Paul Burton <paul.burton@xxxxxxxxxx>
L: linux-mips@xxxxxxxxxxxxxx
S: Supported
F: arch/mips/generic/
+F: arch/mips/tools/generic-board-config.sh
MIPS/LOONGSON1 ARCHITECTURE
M: Keguang Zhang <keguang.zhang@xxxxxxxxx>
diff --git a/arch/mips/Makefile b/arch/mips/Makefile
index 876394554274..a715888179b3 100644
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -486,8 +486,14 @@ $(eval $(call gen_generic_defconfigs,micro32,r2,eb el))
.PHONY: $(generic_defconfigs)
$(generic_defconfigs):
$(Q)$(CONFIG_SHELL) $(srctree)/scripts/kconfig/merge_config.sh \
- -m -O $(objtree) $(srctree)/arch/$(ARCH)/configs/generic_defconfig $^ \
- $(foreach board,$(BOARDS),$(generic_config_dir)/board-$(board).config)
+ -m -O $(objtree) $(srctree)/arch/$(ARCH)/configs/generic_defconfig $^ | \
+ grep -Ev '^#'
+ $(Q)cp $(KCONFIG_CONFIG) $(objtree)/.config.$@
+ $(Q)$(MAKE) -f $(srctree)/Makefile olddefconfig \
+ KCONFIG_CONFIG=$(objtree)/.config.$@ >/dev/null
+ $(Q)$(CONFIG_SHELL) $(srctree)/arch/$(ARCH)/tools/generic-board-config.sh \
+ $(srctree) $(objtree) $(objtree)/.config.$@ $(KCONFIG_CONFIG) \
+ "$(origin BOARDS)" $(BOARDS)
$(Q)$(MAKE) -f $(srctree)/Makefile olddefconfig
#
diff --git a/arch/mips/tools/generic-board-config.sh b/arch/mips/tools/generic-board-config.sh
new file mode 100755
index 000000000000..5c4f93687039
--- /dev/null
+++ b/arch/mips/tools/generic-board-config.sh
@@ -0,0 +1,90 @@
+#!/bin/sh
+#
+# Copyright (C) 2017 Imagination Technologies
+# Author: Paul Burton <paul.burton@xxxxxxxxxx>
+#
+# This program is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 2 of the License, or (at your
+# option) any later version.
+#
+# This script merges configuration fragments for boards supported by the
+# generic MIPS kernel. It checks each for requirements specified using
+# formatted comments, and then calls merge_config.sh to merge those
+# fragments which have no unmet requirements.
+#
+# An example of requirements in your board config fragment might be:
+#
+# # require CONFIG_CPU_MIPS32_R2=y
+# # require CONFIG_CPU_LITTLE_ENDIAN=y
+#
+# This would mean that your board is only included in kernels which are
+# configured for little endian MIPS32r2 CPUs, and not for example in kernels
+# configured for 64 bit or big endian systems.
+#
+
+srctree="$1"
+objtree="$2"
+ref_cfg="$3"
+cfg="$4"
+boards_origin="$5"
+shift 5
+
+cd "${srctree}"
+
+# Only print Skipping... lines if the user explicitly specified BOARDS=. In the
+# general case it only serves to obscure the useful output about what actually
+# was included.
+case ${boards_origin} in
+"command line")
+ print_skipped=1
+ ;;
+environment*)
+ print_skipped=1
+ ;;
+*)
+ print_skipped=0
+ ;;
+esac
+
+for board in $@; do
+ board_cfg="arch/mips/configs/generic/board-${board}.config"
+ if [ ! -f "${board_cfg}" ]; then
+ echo "WARNING: Board config '${board_cfg}' not found"
+ continue
+ fi
+
+ # For each line beginning with # require, cut out the field following
+ # it & search for that in the reference config file. If the requirement
+ # is not found then the subshell will exit with code 1, and we'll
+ # continue on to the next board.
+ grep -E '^# require ' "${board_cfg}" | \
+ cut -d' ' -f 3- | \
+ while read req; do
+ case ${req} in
+ *=y)
+ # If we require something =y then we check that a line
+ # containing it is present in the reference config.
+ grep -Eq "^${req}\$" "${ref_cfg}" && continue
+ ;;
+ *=n)
+ # If we require something =n then we just invert that
+ # check, considering the requirement met if there isn't
+ # a line containing the value =y in the reference
+ # config.
+ grep -Eq "^${req/%=n/=y}\$" "${ref_cfg}" || continue
+ ;;
+ *)
+ echo "WARNING: Unhandled requirement '${req}'"
+ ;;
+ esac
+
+ [ ${print_skipped} -eq 1 ] && echo "Skipping ${board_cfg}"
+ exit 1
+ done || continue
+
+ # Merge this board config fragment into our final config file
+ ./scripts/kconfig/merge_config.sh \
+ -m -O ${objtree} ${cfg} ${board_cfg} \
+ | grep -Ev '^(#|Using)'
+done
--
2.14.0
