arm: tegra2: add .lds to calculate warm boot code size

move away from the current method, where we add wb_end() immediately
after wb_start() and then use the function addresses to calculate the
WB code size. Add a .lds script to expose __wb_end after wb_start() in
the .text section and then reference this variable in the WB size
calculation code.

BUG=chromium-os:23496
TEST=build on Seaboard. Verified that uboot.map has the correct address
assigned to __wb_end and that LP0 works reliably.

Change-Id: I170277f00b450d38063018453faf44d5a38abaaa
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>
Reviewed-on: https://gerrit.chromium.org/gerrit/14682

3 files changed, 44 insertions, 9 deletions

diff --git a/arch/arm/cpu/armv7/tegra2/Makefile b/arch/arm/cpu/armv7/tegra2/Makefile
index cb5c261107..b42a6b31b2 100644
--- a/arch/arm/cpu/armv7/tegra2/Makefile
+++ b/arch/arm/cpu/armv7/tegra2/Makefile
@@ -37,11 +37,17 @@ COBJS-y	:= board.o pinmux.o sys_info.o
 COBJS-$(CONFIG_VIDEO_TEGRA) += display.o
 COBJS-$(CONFIG_TEGRA2_WARMBOOT) += warmboot.o warmboot_avp.o
 
+ifeq ($(CONFIG_TEGRA2_WARMBOOT),y)
+	LDSCRIPT= warmboot_avp.lds
+else
+	LDSCRIPT=
+endif
+
 SOBJS	:= $(SOBJS-y)
 COBJS	:= $(COBJS-y)
 
 SRCS	:= $(SOBJS:.o=.S) $(COBJS:.o=.c)
-OBJS	:= $(addprefix $(obj),$(COBJS) $(SOBJS))
+OBJS	:= $(addprefix $(obj),$(COBJS) $(SOBJS) $(LDSCRIPT))
 
 all:	 $(obj).depend $(LIB)
 
diff --git a/arch/arm/cpu/armv7/tegra2/warmboot_avp.c b/arch/arm/cpu/armv7/tegra2/warmboot_avp.c
index bb1872fe12..121425ba23 100644
--- a/arch/arm/cpu/armv7/tegra2/warmboot_avp.c
+++ b/arch/arm/cpu/armv7/tegra2/warmboot_avp.c
@@ -303,11 +303,3 @@ do_reset:
 	goto do_reset;
 }
 
-/*
- * wb_end() is a dummy function, and must be directly following wb_start(),
- * and is used to calculate the size of wb_start().
- */
-void wb_end(void)
-{
-}
-
diff --git a/arch/arm/cpu/armv7/tegra2/warmboot_avp.lds b/arch/arm/cpu/armv7/tegra2/warmboot_avp.lds
new file mode 100644
index 0000000000..8fc377292b
--- /dev/null
+++ b/arch/arm/cpu/armv7/tegra2/warmboot_avp.lds
@@ -0,0 +1,37 @@
+/*
+ * (C) Copyright 2010 - 2011
+ * NVIDIA Corporation <www.nvidia.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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 program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+OUTPUT_FORMAT("elf32-littlearm", "elf32-littlearm", "elf32-littlearm")
+OUTPUT_ARCH(arm)
+
+SECTIONS
+{
+	. = 0x00000000;
+	. = ALIGN(4);
+
+	.text :
+	{
+		warmboot_avp.o	(.text)
+		__wb_end = .;
+	}
+}