[PATCH v4 15/16] [loongson] add gcc 4.4 support for Loongson2E

[Wu Zhangjin]

because only gcc >=4.4 have loongson-specific support, we need to choose
the suitable -march argument for gcc <= 4.3 and gcc >= 4.4, and here, we
use -march=loongson2e for loongson2e.

thanks goes to Arnaud Patard <apatard@xxxxxxxxxxxx> for suggestion of
using cc-options(Documentation/kbuild/makefiles.txt). and thanks Zhang
Le for introducing the new CPU_LOONGSON2E kernel option.

NOTE: -mtune option is not need if -march and -mtune use the same value.

Signed-off-by: Zhang Le <r0bertz@xxxxxxxxxx>
Signed-off-by: Wu Zhangjin <wuzhangjin@xxxxxxxxx>
---
 arch/mips/Kconfig          |   18 +++++++++++-------
 arch/mips/Makefile         |    6 +++++-
 arch/mips/loongson/Kconfig |    2 +-
 3 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 482dcc3..466920a 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -1030,12 +1030,10 @@ choice
 	prompt "CPU type"
 	default CPU_R4X00
 
-config CPU_LOONGSON2
-	bool "Loongson 2"
-	depends on SYS_HAS_CPU_LOONGSON2
-	select CPU_SUPPORTS_32BIT_KERNEL
-	select CPU_SUPPORTS_64BIT_KERNEL
-	select CPU_SUPPORTS_HIGHMEM
+config CPU_LOONGSON2E
+	bool "Loongson 2E"
+	depends on SYS_HAS_CPU_LOONGSON2E
+	select CPU_LOONGSON2
 	help
 	  The Loongson 2E processor implements the MIPS III instruction set
 	  with many extensions.
@@ -1282,7 +1280,13 @@ config CPU_CAVIUM_OCTEON
 
 endchoice
 
-config SYS_HAS_CPU_LOONGSON2
+config CPU_LOONGSON2
+	bool
+	select CPU_SUPPORTS_32BIT_KERNEL
+	select CPU_SUPPORTS_64BIT_KERNEL
+	select CPU_SUPPORTS_HIGHMEM
+
+config SYS_HAS_CPU_LOONGSON2E
 	bool
 
 config SYS_HAS_CPU_MIPS32_R1
diff --git a/arch/mips/Makefile b/arch/mips/Makefile
index 94d6f58..1efa9aa 100644
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -120,7 +120,11 @@ cflags-$(CONFIG_CPU_R4300)	+= -march=r4300 -Wa,--trap
 cflags-$(CONFIG_CPU_VR41XX)	+= -march=r4100 -Wa,--trap
 cflags-$(CONFIG_CPU_R4X00)	+= -march=r4600 -Wa,--trap
 cflags-$(CONFIG_CPU_TX49XX)	+= -march=r4600 -Wa,--trap
-cflags-$(CONFIG_CPU_LOONGSON2)	+= -march=r4600 -Wa,--trap
+# only gcc >= 4.4 have the loongson-specific support
+cflags-$(CONFIG_CPU_LOONGSON2)	+= -Wa,--trap
+cflags-$(CONFIG_CPU_LOONGSON2E) += \
+	$(call cc-option,-march=loongson2e,-march=r4600)
+
 cflags-$(CONFIG_CPU_MIPS32_R1)	+= $(call cc-option,-march=mips32,-mips32 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS32) \
 			-Wa,-mips32 -Wa,--trap
 cflags-$(CONFIG_CPU_MIPS32_R2)	+= $(call cc-option,-march=mips32r2,-mips32r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS32) \
diff --git a/arch/mips/loongson/Kconfig b/arch/mips/loongson/Kconfig
index 376712a..d450925 100644
--- a/arch/mips/loongson/Kconfig
+++ b/arch/mips/loongson/Kconfig
@@ -7,7 +7,7 @@ config LEMOTE_FULOONG2E
     select ARCH_SPARSEMEM_ENABLE
     select CEVT_R4K
     select CSRC_R4K
-    select SYS_HAS_CPU_LOONGSON2
+    select SYS_HAS_CPU_LOONGSON2E
     select DMA_NONCOHERENT
     select BOOT_ELF32
     select BOARD_SCACHE
-- 
1.6.2.1

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