make main() in snow's romstage.c our romstage entry point

Our earlier attempt was jumping straight from asm to the old u-boot
board_init_f in lowlevel_init_c.c. We are getting ready to transition
to using a real bootblock for ARM, so add romstage.c to the files
compiled and we'll make main() our entry point.

This also updates romstage.ld to place main() (*(.text.startup)) at
the beginning of romstage.

Change-Id: Ifc77a6bfba27d915c4cad62c6c8040665294628a
Signed-off-by: David Hendricks <dhendrix@chromium.org>
Reviewed-on: http://review.coreboot.org/2163
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

src/arch/armv7/Makefile.inc

@@ -148,6 +148,7 @@ CFLAGS += \
 # For various headers imported from Linux
 CFLAGS += -D__LINUX_ARM_ARCH__=7
 
+#crt0s = $(src)/arch/armv7/bootblock.inc
 ldscripts =
 ldscripts += $(src)/arch/armv7/romstage.ld
 
@@ -164,17 +165,18 @@ ifeq ($(CONFIG_LLSHELL),y)
 crt0s += $(src)/arch/armv7/llshell/llshell.inc
 endif
 
-crt0s += $(obj)/mainboard/$(MAINBOARDDIR)/romstage.inc
+# FIXME: do we need romstage.inc? Maybe just get rid of this entirely.
+#crt0s += $(obj)/mainboard/$(MAINBOARDDIR)/romstage.inc
 
 $(obj)/mainboard/$(MAINBOARDDIR)/romstage.pre.inc: $(src)/mainboard/$(MAINBOARDDIR)/romstage.c $(OPTION_TABLE_H) $(obj)/build.h $(obj)/config.h
 	@printf "    CC         romstage.inc\n"
 	$(CC) -MMD $(CFLAGS) -D__PRE_RAM__ -I$(src) -I. -I$(obj) -c -S $< -o $@
 
-$(obj)/mainboard/$(MAINBOARDDIR)/romstage.inc: $(obj)/mainboard/$(MAINBOARDDIR)/romstage.pre.inc
-	@printf "    POST       romstage.inc\n"
-	sed -e 's/\.rodata/.rom.data/g' -e 's/\^\.text/.section .rom.text/g' \
-		-e 's/\^\.section \.text/.section .rom.text/g' $^ > $@.tmp
-	mv $@.tmp $@
+#$(obj)/mainboard/$(MAINBOARDDIR)/romstage.inc: $(obj)/mainboard/$(MAINBOARDDIR)/romstage.pre.inc
+#	@printf "    POST       romstage.inc\n"
+#	sed -e 's/\.rodata/.rom.data/g' -e 's/\^\.text/.section .rom.text/g' \
+#		-e 's/\^\.section \.text/.section .rom.text/g' $^ > $@.tmp
+#	mv $@.tmp $@
 
 # Things that appear in every board
 romstage-srcs += $(objgenerated)/crt0.s

src/arch/armv7/romstage.ld

@@ -43,6 +43,8 @@ SECTIONS
 
 	.romtext . : {
 		_rom = .;
+		_start = .;
+		*(.text.startup);
 		*(.text);
 	}
 

src/mainboard/google/snow/Makefile.inc

@@ -17,7 +17,7 @@
 ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 ##
 
-#romstage-y += romstage.c
+romstage-y += romstage.c
 
 # ramstage-y += ec.c