[U-Boot] [RFC PATCH 1/2] armv7: enable Thumb build for armv7

[Aneesh V <aneesh@ti.com>]

Signed-off-by: Aneesh V <aneesh@ti.com>
---
 README                       |    9 +++++++++
 arch/arm/cpu/armv7/config.mk |    5 +++++
 2 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/README b/README
index f1547a4..ff3a345 100644
--- a/README
+++ b/README
@@ -370,6 +370,15 @@ The following options need to be configured:
 		2. The core frequency as calculated above is multiplied
 		by this value.
 
+- ARM Options:
+		CONFIG_SYS_THUMB_BUILD
+
+		Use this flag to build U-Boot using the Thumb instruction
+		set for ARM architectures. Thumb instruction set provides
+		better code density. For ARM architectures that support
+		Thumb2 this flag will result in Thumb2 code generated by
+		GCC.
+
 - Linux Kernel Interface:
 		CONFIG_CLOCKS_IN_MHZ
 
diff --git a/arch/arm/cpu/armv7/config.mk b/arch/arm/cpu/armv7/config.mk
index 49ac9c7..b7bebad 100644
--- a/arch/arm/cpu/armv7/config.mk
+++ b/arch/arm/cpu/armv7/config.mk
@@ -31,3 +31,8 @@ PLATFORM_CPPFLAGS += -march=armv5
 # =========================================================================
 PLATFORM_RELFLAGS +=$(call cc-option,-mshort-load-bytes,\
 		    $(call cc-option,-malignment-traps,))
+
+ifeq ($(CONFIG_SYS_THUMB_BUILD),y)
+# Enable Thumb mode build if compiler supports it
+PLATFORM_CPPFLAGS += $(call cc-option,-mthumb -mthumb-interwork)
+endif
-- 
1.7.0.4