[Buildroot] [PATCH v2 1/2] MIPS: add support for XBurst cores

[Vicente Olivert Riera]

- There isn't any matching -march option for this core family, so we
  need to stick with the generic mips32r2.
- Add an option to the toolchain wrapper to avoid an FPU bug.

Related: http://www.ingenic.com/en/?xburst.html

Signed-off-by: Vicente Olivert Riera <Vincent.Riera at imgtec.com>

---
Changes v1 -> v2:
 - Do not add -mmxu to the wrapper.
---
 arch/Config.in.mips            | 5 +++++
 toolchain/toolchain-wrapper.c  | 3 +++
 toolchain/toolchain-wrapper.mk | 5 +++++
 3 files changed, 13 insertions(+)

diff --git a/arch/Config.in.mips b/arch/Config.in.mips
index 3662fed..3075d3f 100644
--- a/arch/Config.in.mips
+++ b/arch/Config.in.mips
@@ -63,6 +63,10 @@ config BR2_mips_p5600
 	bool "P5600"
 	depends on !BR2_ARCH_IS_64
 	select BR2_MIPS_CPU_MIPS32R5
+config BR2_mips_xburst
+	bool "XBurst"
+	depends on !BR2_ARCH_IS_64
+	select BR2_MIPS_CPU_MIPS32R2
 config BR2_mips_64
 	bool "Generic MIPS64"
 	depends on BR2_ARCH_IS_64
@@ -137,6 +141,7 @@ config BR2_GCC_TARGET_ARCH
 	default "m5101"		if BR2_mips_m5101
 	default "m6201"		if BR2_mips_m6201
 	default "p5600"		if BR2_mips_p5600
+	default "mips32r2"	if BR2_mips_xburst
 	default "mips64"	if BR2_mips_64
 	default "mips64r2"	if BR2_mips_64r2
 	default "mips64r5"	if BR2_mips_64r5
diff --git a/toolchain/toolchain-wrapper.c b/toolchain/toolchain-wrapper.c
index 925d013..d59629b 100644
--- a/toolchain/toolchain-wrapper.c
+++ b/toolchain/toolchain-wrapper.c
@@ -66,6 +66,9 @@ static char *predef_args[] = {
 #ifdef BR_OMIT_LOCK_PREFIX
 	"-Wa,-momit-lock-prefix=yes",
 #endif
+#ifdef BR_NO_FUSED_MADD
+	"-mno-fused-madd",
+#endif
 #ifdef BR_BINFMT_FLAT
 	"-Wl,-elf2flt",
 #endif
diff --git a/toolchain/toolchain-wrapper.mk b/toolchain/toolchain-wrapper.mk
index af39071..dc3210d 100644
--- a/toolchain/toolchain-wrapper.mk
+++ b/toolchain/toolchain-wrapper.mk
@@ -26,6 +26,11 @@ ifeq ($(BR2_x86_x1000),y)
 TOOLCHAIN_WRAPPER_ARGS += -DBR_OMIT_LOCK_PREFIX
 endif
 
+# Avoid FPU bug on XBurst CPUs
+ifeq ($(BR2_mips_xburst),y)
+TOOLCHAIN_WRAPPER_ARGS += -DBR_NO_FUSED_MADD
+endif
+
 ifeq ($(BR2_CCACHE_USE_BASEDIR),y)
 TOOLCHAIN_WRAPPER_ARGS += -DBR_CCACHE_BASEDIR='"$(BASE_DIR)"'
 endif
-- 
2.10.1