* [PATCH 3.13 03/46] clocksource: vf_pit_timer: use complement for sched_clock reading
[not found] <20140328173134.630198216@linuxfoundation.org>
@ 2014-03-28 17:31 ` Greg Kroah-Hartman
0 siblings, 0 replies; only message in thread
From: Greg Kroah-Hartman @ 2014-03-28 17:31 UTC (permalink / raw)
To: linux-arm-kernel
3.13-stable review patch. If anyone has any objections, please let me know.
------------------
From: Stefan Agner <stefan@agner•ch>
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 <stefan@agner•ch>
Acked-by: Shawn Guo <shawn.guo@linaro•org>
Cc: daniel.lezcano at linaro.org
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux at arm.linux.org.uk
Link: http://lkml.kernel.org/r/d25af915993aec1b486be653eb86f748ddef54fe.1394057313.git.stefan at agner.ch
Signed-off-by: Thomas Gleixner <tglx@linutronix•de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation•org>
---
drivers/clocksource/vf_pit_timer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/clocksource/vf_pit_timer.c
+++ b/drivers/clocksource/vf_pit_timer.c
@@ -54,7 +54,7 @@ static inline void pit_irq_acknowledge(v
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)
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[not found] <20140328173134.630198216@linuxfoundation.org>
2014-03-28 17:31 ` [PATCH 3.13 03/46] clocksource: vf_pit_timer: use complement for sched_clock reading Greg Kroah-Hartman
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