@@ -16,6 +16,7 @@
#include <linux/notifier.h>
#include <linux/of_irq.h>
#include <linux/percpu.h>
+#include <linux/sched_clock.h>
#include <linux/smp.h>
#include <linux/time.h>
#include <asm/mips-cps.h>
@@ -24,13 +25,10 @@ static DEFINE_PER_CPU(struct clock_event_device, gic_clockevent_device);
static int gic_timer_irq;
static unsigned int gic_frequency;
-static u64 notrace gic_read_count(void)
+static u64 notrace gic_read_count_2x32(void)
{
unsigned int hi, hi2, lo;
- if (mips_cm_is64)
- return read_gic_counter();
-
do {
hi = read_gic_counter_32h();
lo = read_gic_counter_32l();
@@ -40,6 +38,19 @@ static u64 notrace gic_read_count(void)
return (((u64) hi) << 32) + lo;
}
+static u64 notrace gic_read_count_64(void)
+{
+ return read_gic_counter();
+}
+
+static u64 notrace gic_read_count(void)
+{
+ if (mips_cm_is64)
+ return gic_read_count_64();
+
+ return gic_read_count_2x32();
+}
+
static int gic_next_event(unsigned long delta, struct clock_event_device *evt)
{
int cpu = cpumask_first(evt->cpumask);
@@ -228,6 +239,18 @@ static int __init gic_clocksource_of_init(struct device_node *node)
/* And finally start the counter */
clear_gic_config(GIC_CONFIG_COUNTSTOP);
+ /*
+ * It's safe to use the MIPS GIC timer as a sched clock source only if
+ * its ticks are stable, which is true on either the platforms with
+ * stable CPU frequency or on the platforms with CM3 and CPU frequency
+ * change performed by the CPC core clocks divider.
+ */
+ if (mips_cm_revision() >= CM_REV_CM3 || !IS_ENABLED(CONFIG_CPU_FREQ)) {
+ sched_clock_register(mips_cm_is64 ?
+ gic_read_count_64 : gic_read_count_2x32,
+ 64, gic_frequency);
+ }
+
return 0;
}
TIMER_OF_DECLARE(mips_gic_timer, "mti,gic-timer",