add check infrastructure, default sparse

Add support for running source code checkers on u-boot source, e.g.,
using sparse to aid with typechecking.  This comes in especially
handy as SoC vendors mix and match cores and devices with different
endianness, thus here we add CHECK_ENDIAN to the otherwise linux
kernel default CHECKFLAGS.

Signed-off-by: Kim Phillips <kim.phillips@freescale.com>

Makefile

@@ -92,6 +92,24 @@ BUILD_DIR := $(O)
 endif
 endif
 
+# Call a source code checker (by default, "sparse") as part of the
+# C compilation.
+#
+# Use 'make C=1' to enable checking of re-compiled files.
+#
+# See the linux kernel file "Documentation/sparse.txt" for more details,
+# including where to get the "sparse" utility.
+
+ifdef C
+ifeq ("$(origin C)", "command line")
+CHECKSRC := $(C)
+endif
+endif
+ifndef CHECKSRC
+  CHECKSRC = 0
+endif
+export CHECKSRC
+
 ifneq ($(BUILD_DIR),)
 saved-output := $(BUILD_DIR)
 

config.mk

@@ -149,6 +149,7 @@ OBJCOPY = $(CROSS_COMPILE)objcopy
 OBJDUMP = $(CROSS_COMPILE)objdump
 RANLIB	= $(CROSS_COMPILE)RANLIB
 DTC	= dtc
+CHECK	= sparse
 
 #########################################################################
 
@@ -275,6 +276,10 @@ ifneq ($(CONFIG_SPL_TEXT_BASE),)
 LDFLAGS_u-boot-spl += -Ttext $(CONFIG_SPL_TEXT_BASE)
 endif
 
+# Linus' kernel sanity checking tool
+CHECKFLAGS     := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \
+                  -Wbitwise -Wno-return-void -D__CHECK_ENDIAN__ $(CF)
+
 # Location of a usable BFD library, where we define "usable" as
 # "built for ${HOST}, supports ${TARGET}".  Sensible values are
 # - When cross-compiling: the root of the cross-environment
@@ -322,6 +327,9 @@ $(obj)%.s:	%.S
 $(obj)%.o:	%.S
 	$(CC)  $(ALL_AFLAGS) -o $@ $< -c
 $(obj)%.o:	%.c
+ifneq ($(CHECKSRC),0)
+	$(CHECK) $(CHECKFLAGS) $(ALL_CFLAGS) $<
+endif
 	$(CC)  $(ALL_CFLAGS) -o $@ $< -c
 $(obj)%.i:	%.c
 	$(CPP) $(ALL_CFLAGS) -o $@ $< -c