New Loongson-3 (Loongson-3A R2, Loongson-3A R3, and newer) has SFB
(Store Fill Buffer) which can improve the performance of memory access.
Now, SFB enablement is controlled by CONFIG_LOONGSON3_ENHANCEMENT, and
the generic kernel has no benefit from SFB (even it is running on a new
Loongson-3 machine). With this patch, we can enable SFB at runtime by
detecting the CPU type (the expense is war_io_reorder_wmb() will always
be a 'sync', which will hurt the performance of old Loongson-3).
Signed-off-by: Huacai Chen <chenhc@xxxxxxxxxx>
---
arch/mips/include/asm/io.h | 2 +-
arch/mips/include/asm/mach-loongson64/kernel-entry-init.h | 14 ++++++++++----
2 files changed, 11 insertions(+), 5 deletions(-)
diff --git a/arch/mips/include/asm/io.h b/arch/mips/include/asm/io.h
index 0cbf3af..5146efa 100644
--- a/arch/mips/include/asm/io.h
+++ b/arch/mips/include/asm/io.h
@@ -304,7 +304,7 @@ static inline void iounmap(const volatile void __iomem *addr)
#undef __IS_KSEG1
}
-#if defined(CONFIG_CPU_CAVIUM_OCTEON) || defined(CONFIG_LOONGSON3_ENHANCEMENT)
+#if defined(CONFIG_CPU_CAVIUM_OCTEON) || defined(CONFIG_CPU_LOONGSON3)
#define war_io_reorder_wmb() wmb()
#else
#define war_io_reorder_wmb() do { } while (0)
diff --git a/arch/mips/include/asm/mach-loongson64/kernel-entry-init.h b/arch/mips/include/asm/mach-loongson64/kernel-entry-init.h
index 3127391..4b7f58a 100644
--- a/arch/mips/include/asm/mach-loongson64/kernel-entry-init.h
+++ b/arch/mips/include/asm/mach-loongson64/kernel-entry-init.h
@@ -26,12 +26,15 @@
mfc0 t0, CP0_PAGEGRAIN
or t0, (0x1 << 29)
mtc0 t0, CP0_PAGEGRAIN
-#ifdef CONFIG_LOONGSON3_ENHANCEMENT
/* Enable STFill Buffer */
+ mfc0 t0, CP0_PRID
+ andi t0, 0xffff
+ slti t0, 0x6308
+ bnez t0, 1f
mfc0 t0, CP0_CONFIG6
or t0, 0x100
mtc0 t0, CP0_CONFIG6
-#endif
+1:
_ehb
.set pop
#endif
@@ -52,12 +55,15 @@
mfc0 t0, CP0_PAGEGRAIN
or t0, (0x1 << 29)
mtc0 t0, CP0_PAGEGRAIN
-#ifdef CONFIG_LOONGSON3_ENHANCEMENT
/* Enable STFill Buffer */
+ mfc0 t0, CP0_PRID
+ andi t0, 0xffff
+ slti t0, 0x6308
+ bnez t0, 1f
mfc0 t0, CP0_CONFIG6
or t0, 0x100
mtc0 t0, CP0_CONFIG6
-#endif
+1:
_ehb
.set pop
#endif
--
2.7.0
