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-rw-r--r--arch/arm/mach-pxa/time.c39
1 files changed, 39 insertions, 0 deletions
diff --git a/arch/arm/mach-pxa/time.c b/arch/arm/mach-pxa/time.c
index 98d27e646b0..7916311547c 100644
--- a/arch/arm/mach-pxa/time.c
+++ b/arch/arm/mach-pxa/time.c
@@ -16,11 +16,48 @@
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/clockchips.h>
+#include <linux/sched.h>
+#include <asm/div64.h>
+#include <asm/cnt32_to_63.h>
#include <asm/mach/irq.h>
#include <asm/mach/time.h>
#include <asm/arch/pxa-regs.h>
+/*
+ * This is PXA's sched_clock implementation. This has a resolution
+ * of at least 308 ns and a maximum value of 208 days.
+ *
+ * The return value is guaranteed to be monotonic in that range as
+ * long as there is always less than 582 seconds between successive
+ * calls to sched_clock() which should always be the case in practice.
+ */
+
+#define OSCR2NS_SCALE_FACTOR 10
+
+static unsigned long oscr2ns_scale;
+
+static void __init set_oscr2ns_scale(unsigned long oscr_rate)
+{
+ unsigned long long v = 1000000000ULL << OSCR2NS_SCALE_FACTOR;
+ do_div(v, oscr_rate);
+ oscr2ns_scale = v;
+ /*
+ * We want an even value to automatically clear the top bit
+ * returned by cnt32_to_63() without an additional run time
+ * instruction. So if the LSB is 1 then round it up.
+ */
+ if (oscr2ns_scale & 1)
+ oscr2ns_scale++;
+}
+
+unsigned long long sched_clock(void)
+{
+ unsigned long long v = cnt32_to_63(OSCR);
+ return (v * oscr2ns_scale) >> OSCR2NS_SCALE_FACTOR;
+}
+
+
static irqreturn_t
pxa_ost0_interrupt(int irq, void *dev_id)
{
@@ -152,6 +189,8 @@ static void __init pxa_timer_init(void)
OIER = 0;
OSSR = OSSR_M0 | OSSR_M1 | OSSR_M2 | OSSR_M3;
+ set_oscr2ns_scale(CLOCK_TICK_RATE);
+
ckevt_pxa_osmr0.mult =
div_sc(CLOCK_TICK_RATE, NSEC_PER_SEC, ckevt_pxa_osmr0.shift);
ckevt_pxa_osmr0.max_delta_ns =