arch: add support for Andes 32-bit (nds32)

This commit provides basic support for the Andes 32-bit (nds32)
architecture.

Signed-off-by: Che-Wei Chuang <cnoize@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>
Signed-off-by: Nylon Chen <nylon7@andestech.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

DEVELOPERS

@@ -1667,6 +1667,9 @@ F:	package/trousers/
 N:	Norbert Lange <nolange79@gmail.com>
 F:	package/tcf-agent/
 
+N:	Nylon Chen <nylon7@andestech.com>
+F:	arch/Config.in.nds32
+
 N:	Olaf Rempel <razzor@kopf-tisch.de>
 F:	package/ctorrent/
 

arch/Config.in

@@ -154,6 +154,14 @@ config BR2_mips64el
 	  http://www.mips.com/
 	  http://en.wikipedia.org/wiki/MIPS_Technologies
 
+config BR2_nds32
+	bool "nds32"
+	select BR2_ARCH_HAS_NO_TOOLCHAIN_BUILDROOT
+	select BR2_ARCH_HAS_MMU_MANDATORY
+	help
+	  nds32 is a 32-bit architecture developed by Andes Technology.
+	  https://en.wikipedia.org/wiki/Andes_Technology
+
 config BR2_nios2
 	bool "Nios II"
 	select BR2_ARCH_HAS_MMU_MANDATORY
@@ -419,6 +427,10 @@ if BR2_mips || BR2_mips64 || BR2_mipsel || BR2_mips64el
 source "arch/Config.in.mips"
 endif
 
+if BR2_nds32
+source "arch/Config.in.nds32"
+endif
+
 if BR2_nios2
 source "arch/Config.in.nios2"
 endif

arch/Config.in.nds32

@@ -0,0 +1,11 @@
+config BR2_ARCH
+	default "nds32"
+
+config BR2_GCC_TARGET_ARCH
+	default "v3"
+
+config BR2_ENDIAN
+	default "LITTLE"
+
+config BR2_READELF_ARCH_NAME
+	default "Andes Technology compact code size embedded RISC processor family"