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authorMarc Zyngier <marc.zyngier@arm.com>2011-01-14 15:32:36 +0000
committerMarc Zyngier <marc.zyngier@arm.com>2012-04-27 13:35:33 +0100
commit3f61c80eb7dff0fb35beb8068852d3fc902315a6 (patch)
tree33f1285e1bac944b3279993b14cbfc196abf570e /arch/arm/kernel/arch_timer.c
parent022c03a2d650c641fa0f94dbc9d9ff77f8057678 (diff)
downloadlinux-3f61c80eb7dff0fb35beb8068852d3fc902315a6.tar.bz2
ARM: architected timers: Add A15 specific sched_clock implementation
Provide an A15 sched_clock implementation using the virtual counter, which is thought to be more useful than the physical one in a virtualised environment, as it can offset the time spent in another VM or the hypervisor. Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'arch/arm/kernel/arch_timer.c')
-rw-r--r--arch/arm/kernel/arch_timer.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/arch/arm/kernel/arch_timer.c b/arch/arm/kernel/arch_timer.c
index bb9a8b45bffa..dd907048f571 100644
--- a/arch/arm/kernel/arch_timer.c
+++ b/arch/arm/kernel/arch_timer.c
@@ -23,6 +23,7 @@
#include <asm/localtimer.h>
#include <asm/arch_timer.h>
#include <asm/system_info.h>
+#include <asm/sched_clock.h>
static unsigned long arch_timer_rate;
static int arch_timer_ppi;
@@ -204,6 +205,18 @@ static inline cycle_t arch_counter_get_cntvct(void)
return ((cycle_t) cvalh << 32) | cvall;
}
+static u32 notrace arch_counter_get_cntvct32(void)
+{
+ cycle_t cntvct = arch_counter_get_cntvct();
+
+ /*
+ * The sched_clock infrastructure only knows about counters
+ * with at most 32bits. Forget about the upper 24 bits for the
+ * time being...
+ */
+ return (u32)(cntvct & (u32)~0);
+}
+
static cycle_t arch_counter_read(struct clocksource *cs)
{
return arch_counter_get_cntpct();
@@ -286,3 +299,15 @@ out_free:
return err;
}
+
+int __init arch_timer_sched_clock_init(void)
+{
+ int err;
+
+ err = arch_timer_available();
+ if (err)
+ return err;
+
+ setup_sched_clock(arch_counter_get_cntvct32, 32, arch_timer_rate);
+ return 0;
+}