From: johlstei@codeaurora.org (Jeff Ohlstein)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2] msm: timer: compensate for timer shift in msm_read_timer_count
Date: Fri, 17 Jun 2011 13:55:38 -0700 [thread overview]
Message-ID: <1308344138-2862-1-git-send-email-johlstei@codeaurora.org> (raw)
Some msm targets have timers whose lower bits are unreliable. So, we
present our timers as lower frequency than they actually are, and ignore
the bottom 5 bits on such targets. This compensation was erroneously
removed from the msm_read_timer_count function, so restore it.
This was broken by 94790ec25 "msm: timer: SMP timer support for msm".
Signed-off-by: Jeff Ohlstein <johlstei@codeaurora.org>
---
arch/arm/mach-msm/timer.c | 6 +++++-
1 files changed, 5 insertions(+), 1 deletions(-)
diff --git a/arch/arm/mach-msm/timer.c b/arch/arm/mach-msm/timer.c
index 38b95e9..608ec4d 100644
--- a/arch/arm/mach-msm/timer.c
+++ b/arch/arm/mach-msm/timer.c
@@ -100,7 +100,11 @@ static cycle_t msm_read_timer_count(struct clocksource *cs)
{
struct msm_clock *clk = container_of(cs, struct msm_clock, clocksource);
- return readl(clk->global_counter);
+ /*
+ * Shift timer count down by a constant due to unreliable lower bits
+ * on some targets.
+ */
+ return readl(clk->global_counter) >> clk->shift;
}
static struct msm_clock *clockevent_to_clock(struct clock_event_device *evt)
--
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
next reply other threads:[~2011-06-17 20:55 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-17 20:55 Jeff Ohlstein [this message]
2011-06-20 21:59 ` [stable] [PATCH v2] msm: timer: compensate for timer shift in msm_read_timer_count Greg KH
2011-06-20 23:27 ` David Brown
2011-06-21 16:24 ` Greg KH
2011-07-05 19:15 ` Jeff Ohlstein
2011-07-06 2:45 ` Greg KH
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