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>
diff --git a/arch/arm/kernel/arch_timer.c b/arch/arm/kernel/arch_timer.c
index bb9a8b4..dd90704 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 @@
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 @@
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;
+}