From: Stefan Agner Date: Wed, 5 Mar 2014 22:11:08 +0000 (+0100) Subject: clocksource: vf_pit_timer: use complement for sched_clock reading X-Git-Tag: submit/tizen_common/20140905.094502~294 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=07a2f05ccb2b392a0360653eb6f9d32906e2d516;p=sdk%2Femulator%2Femulator-kernel.git clocksource: vf_pit_timer: use complement for sched_clock reading commit 224aa3ed45c8735ae02bb2ecca002409fa6aa772 upstream. Vybrids PIT register is monitonic decreasing. However, sched_clock reading needs to be monitonic increasing. Use bitwise not to get the complement of the clock register. This fixes the clock going backward. Also, the clock now starts at 0 since we load the register with the maximum value at start. Signed-off-by: Stefan Agner Acked-by: Shawn Guo Cc: daniel.lezcano@linaro.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux@arm.linux.org.uk Link: http://lkml.kernel.org/r/d25af915993aec1b486be653eb86f748ddef54fe.1394057313.git.stefan@agner.ch Signed-off-by: Thomas Gleixner Signed-off-by: Jiri Slaby --- diff --git a/drivers/clocksource/vf_pit_timer.c b/drivers/clocksource/vf_pit_timer.c index 587e0202a70b..e5590953630e 100644 --- a/drivers/clocksource/vf_pit_timer.c +++ b/drivers/clocksource/vf_pit_timer.c @@ -54,7 +54,7 @@ static inline void pit_irq_acknowledge(void) static unsigned int pit_read_sched_clock(void) { - return __raw_readl(clksrc_base + PITCVAL); + return ~__raw_readl(clksrc_base + PITCVAL); } static int __init pit_clocksource_init(unsigned long rate)