This patch enables the 'write full line for zeros mode' feature of cortex-A9.
The performance of memset() with zero is increased about 10% with this patch.
Signed-off-by: Boojin Kim <boojin.kim@xxxxxxxxxxx>
---
arch/arm/mach-exynos4/platsmp.c | 18 ++++++++++++++++++
1 files changed, 18 insertions(+), 0 deletions(-)
diff --git a/arch/arm/mach-exynos4/platsmp.c b/arch/arm/mach-exynos4/platsmp.c
index d5f0f29..edf7054 100644
--- a/arch/arm/mach-exynos4/platsmp.c
+++ b/arch/arm/mach-exynos4/platsmp.c
@@ -90,6 +90,16 @@ static void __cpuinit exynos4_gic_secondary_init(void)
__raw_writel(1, cpu_base + GIC_CPU_CTRL);
}
+static void enable_foz(void)
+{
+ u32 val;
+ asm volatile(
+ "mrc p15, 0, %0, c1, c0, 1\n"
+ "orr %0, %0, #(1 << 3)\n"
+ "mcr p15, 0, %0, c1, c0, 1"
+ : "=r" (val));
+}
+
void __cpuinit platform_secondary_init(unsigned int cpu)
{
/*
@@ -106,6 +116,14 @@ void __cpuinit platform_secondary_init(unsigned int cpu)
write_pen_release(-1);
/*
+ * Enable write full line for zeros mode
+ */
+ if (soc_is_exynos4210() | soc_is_exynos4212() | soc_is_exynos4412()) {
+ enable_foz();
+ smp_call_function((void (*)(void *))enable_foz, NULL, 0);
+ }
+
+ /*
* Synchronise with the boot thread.
*/
spin_lock(&boot_lock);
--
1.7.1
--
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