Use DEC I/O ASIC's free-running counter for sched_clock source. This
implementation will give high resolution cputime accounting.
Acked-by: Maciej W. Rozycki <macro@xxxxxxxxxxxxxx>
Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@xxxxxxxxxx>
---
arch/mips/kernel/csrc-ioasic.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/arch/mips/kernel/csrc-ioasic.c b/arch/mips/kernel/csrc-ioasic.c
index 54e394d..722f558 100644
--- a/arch/mips/kernel/csrc-ioasic.c
+++ b/arch/mips/kernel/csrc-ioasic.c
@@ -14,6 +14,7 @@
* GNU General Public License for more details.
*/
#include <linux/clocksource.h>
+#include <linux/sched_clock.h>
#include <linux/init.h>
#include <asm/ds1287.h>
@@ -33,6 +34,11 @@ static struct clocksource clocksource_dec = {
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
+static u64 notrace dec_ioasic_read_sched_clock(void)
+{
+ return ioasic_read(IO_REG_FCTR);
+}
+
int __init dec_ioasic_clocksource_init(void)
{
unsigned int freq;
@@ -61,5 +67,8 @@ int __init dec_ioasic_clocksource_init(void)
clocksource_dec.rating = 200 + freq / 10000000;
clocksource_register_hz(&clocksource_dec, freq);
+
+ sched_clock_register(dec_ioasic_read_sched_clock, 32, freq);
+
return 0;
}
--
2.3.2
