linux.git/drivers/rtc, branch v3.1-rc5

drivers/rtc/rtc-s3c.c: allow multiple open / allow no-ioctl-open'ed rtc to have irq.

2011-08-26T01:51:00+00:00

The previous rtc-s3c had two issues related with its IRQ.

1. Users cannot open rtc multiple times because an open operation
   calls request_irq on the same IRQ.  (e.g., two user processes wants to
   open and read RTC time from rtc-s3c at the same time)

2. If alarm is set and no one has the rtc opened with filesystem
   (either the alarm is set by kernel/boot-loader or user set an alarm and
   closed rtc dev file), the pending bit is not cleared and no further
   interrupt is invoked.  When the alarm is used by the system itself such
   as a resume from suspend-to-RAM or other Low-power modes/idle, this is
   a critical issue.

This patch mitigates these issues by calling request_irq at probe and
free_irq at remove.

Signed-off-by: MyungJoo Ham 
Signed-off-by: Kyungmin Park 
Acked-by: Kukjin Kim 
Cc: Alessandro Zummo 
Cc: Changhwan Youn 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

drivers/rtc/rtc-s3c.c: correct debug messages

2011-08-26T01:50:43+00:00

RTC-S3C used to print out debug messages incorrectly.  This patch
corrects incorrect outputs.  (undecoded bcd numbers, incorrectly decoded
register values)

This patch affects the pr-debug messages only.

Signed-off-by: MyungJoo Ham 
Signed-off-by: Kyungmin Park 
Acked-by: Kukjin Kim 
Cc: Alessandro Zummo 
Cc: Changhwan Youn 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2011-08-17T17:28:33+00:00

* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  rtc: Limit RTC PIE frequency
  rtc: Fix hrtimer deadlock
  rtc: Handle errors correctly in rtc_irq_set_state()

Fixup trivial conflicts in drivers/rtc/interface.c due to slightly
trivially versions of the same patch coming in two different ways.

rtc-omap: fix initialization of control register

2011-08-04T00:25:20+00:00

As the comment explains, the intention of the code is to clear the
OMAP_RTC_CTRL_MODE_12_24 bit, but instead it only clears the
OMAP_RTC_CTRL_SPLIT and OMAP_RTC_CTRL_AUTO_COMP bits, which should be
kept.  OMAP_RTC_CTRL_DISABLE, OMAP_RTC_CTRL_SET_32_COUNTER,
OMAP_RTC_CTRL_TEST, and OMAP_RTC_CTRL_ROUND_30S are also better off
being cleared.

Signed-off-by: Daniel Glöckner 
Cc: Alessandro Zummo 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

rtc: fix hrtimer deadlock

2011-07-26T23:49:42+00:00

Ben reported a lockup related to rtc. The lockup happens due to:

CPU0                                        CPU1

rtc_irq_set_state()			    __run_hrtimer()
  spin_lock_irqsave(&rtc->irq_task_lock)    rtc_handle_legacy_irq();
					      spin_lock(&rtc->irq_task_lock);
  hrtimer_cancel()
    while (callback_running);

So the running callback never finishes as it's blocked on
rtc->irq_task_lock.

Use hrtimer_try_to_cancel() instead and drop rtc->irq_task_lock while
waiting for the callback.  Fix this for both rtc_irq_set_state() and
rtc_irq_set_freq().

Signed-off-by: Thomas Gleixner 
Reported-by: Ben Greear 
Cc: John Stultz 
Cc: Ingo Molnar 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

rtc: limit frequency

2011-07-26T23:49:42+00:00

Due to the hrtimer self rearming mode a user can DoS the machine simply
because it's starved by hrtimer events.

The RTC hrtimer is self rearming.  We really need to limit the frequency
to something sensible.

Signed-off-by: Thomas Gleixner 
Cc: John Stultz 
Cc: Ingo Molnar 
Cc: Ben Greear 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

rtc: handle errors correctly in rtc_irq_set_state()

2011-07-26T23:49:41+00:00

The code checks the correctness of the parameters, but unconditionally
arms/disarms the hrtimer.

The result is that a random task might arm/disarm rtc timer and surprise
the real owner by either generating events or by stopping them.

Signed-off-by: Thomas Gleixner 
Cc: John Stultz 
Cc: Ingo Molnar 
Cc: Ben Greear 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

rtc: Limit RTC PIE frequency

2011-07-26T21:50:01+00:00

The RTC pie hrtimer is self rearming. We really need to limit the
frequency to something sensible. Thus limit it to the 8192Hz max
value from the rtc man documentation

Cc: Willy Tarreau 
Cc: stable@kernel.org
Signed-off-by: Thomas Gleixner 
[jstultz: slightly reworked to use RTC_MAX_FREQ value]
Signed-off-by: John Stultz

rtc: Fix hrtimer deadlock

2011-07-26T21:49:59+00:00

Ben reported a lockup related to rtc. The lockup happens due to:

CPU0                                        CPU1

rtc_irq_set_state()			    __run_hrtimer()
  spin_lock_irqsave(&rtc->irq_task_lock)    rtc_handle_legacy_irq();
					      spin_lock(&rtc->irq_task_lock);
  hrtimer_cancel()
    while (callback_running);

So the running callback never finishes as it's blocked on
rtc->irq_task_lock.

Use hrtimer_try_to_cancel() instead and drop rtc->irq_task_lock while
waiting for the callback. Fix this for both rtc_irq_set_state() and
rtc_irq_set_freq().

Cc: stable@kernel.org
Reported-by: Ben Greear 
Signed-off-by: Thomas Gleixner 
Signed-off-by: John Stultz

rtc: Handle errors correctly in rtc_irq_set_state()

2011-07-26T21:49:57+00:00

In rtc_irq_set_state, the code checks the correctness of the parameters,
but then goes on to unconditionally arms/disarms the hrtimer. Thus a
random task might arm/disarm rtc timer and surprise the real owner by
either generating events or by stopping them.

Cc: stable@kernel.org
Signed-off-by: Thomas Gleixner 
Signed-off-by: John Stultz