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: v3.14-rc8~16^2 X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=224aa3ed45c8735ae02bb2ecca002409fa6aa772;p=~emulex%2Finfiniband.git clocksource: vf_pit_timer: use complement for sched_clock reading 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 Cc: stable@vger.kernel.org Signed-off-by: Thomas Gleixner --- diff --git a/drivers/clocksource/vf_pit_timer.c b/drivers/clocksource/vf_pit_timer.c index 02821b06a39..a918bc481c5 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 u64 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)