This is a note to let you know that I have just added a patch titled
clocksource: vf_pit_timer: use complement for sched_clock reading
to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree
which can be found at:
http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Luis
------
From 1a35c24db888b0a2b48933680ed8fd490bddf680 Mon Sep 17 00:00:00 2001
From: Stefan Agner <stefan@agner.ch>
Date: Wed, 5 Mar 2014 23:11:08 +0100
Subject: 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 <stefan@agner.ch>
Acked-by: Shawn Guo <redacted>
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 <redacted>
Signed-off-by: Luis Henriques <redacted>
---
drivers/clocksource/vf_pit_timer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/clocksource/vf_pit_timer.c b/drivers/clocksource/vf_pit_timer.c
index 587e020..e559095 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)
--1.9.1