The function name is now renamed to 'timer_probe' for consistency with
the CLOCKSOURCE_OF_DECLARE => TIMER_OF_DECLARE change.
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NHeiko Stuebner <heiko@sntech.de>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>

The CLOCKSOURCE_OF_DECLARE macro is used widely for the timers to declare the
clocksource at early stage. However, this macro is also used to initialize
the clockevent if any, or the clockevent only.

It was originally suggested to declare another macro to initialize a
clockevent, so in order to separate the two entities even they belong to the
same IP. This was not accepted because of the impact on the DT where splitting
a clocksource/clockevent definition does not make sense as it is a Linux
concept not a hardware description.

On the other side, the clocksource has not interrupt declared while the
clockevent has, so it is easy from the driver to know if the description is
for a clockevent or a clocksource, IOW it could be implemented at the driver
level.

So instead of dealing with a named clocksource macro, let's use a more generic
one: TIMER_OF_DECLARE.

The patch has not functional changes.
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: NHeiko Stuebner <heiko@sntech.de>
Acked-by: NNeil Armstrong <narmstrong@baylibre.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NMatthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>

After discussing it, this feature is dropped as it is not considered
adequate:

	https://patchwork.kernel.org/patch/9639317/

There is no user of this macro yet, so there is no impact on the drivers.

This reverts commit 376bc271.

Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>

The recent changes made the fttmr010 to be more generic and support different
timers with a very few differences like moxart or aspeed.

The aspeed timer uses a countdown and there is a test against the aspeed2400
compatible string to set a flag.

With the previous patch, we added the aspeed2500 compatible string but without
taking care of setting the countdown flag.

Fix this by specifiying a init function and pass the aspeed flag to a common
init function.
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Tested-by: NAndrew Jeffery <andrew@aj.id.au>
Reviewed-by: NAndrew Jeffery <andrew@aj.id.au>
Acked-by: NJoel Stanley <joel@jms.id.au>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>

Also clean up space-before-tab issues in the documentation.
Signed-off-by: NAndrew Jeffery <andrew@aj.id.au>
Acked-by: NJoel Stanley <joel@jms.id.au>
Acked-by: NRob Herring <robh@kernel.org>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>

This merges the Moxa Art timer driver into the Faraday FTTMR010
driver and replaces all Kconfig symbols to use the Faraday
driver instead. We are now so similar that the drivers can
be merged by just adding a few lines to the Faraday timer.

Differences:

- The Faraday driver explicitly sets the counter to count
  upwards for the clocksource, removing the need for the
  clocksource core to invert the value.

- The Faraday driver also handles sched_clock()

On the Aspeed, the counter can only count downwards, so support
the timers in downward-counting mode as well, and flag the
Aspeed to use this mode. This mode was tested on the Gemini so
I have high hopes that it'll work fine on the Aspeed as well.

After this we have one driver for all three SoCs and a generic
Faraday FTTMR010 timer driver, which is nice.

Cc: Joel Stanley <joel@jms.id.au>
Cc: Jonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NJoel Stanley <joel@jms.id.au>
Tested-by: NJoel Stanley <joel@jms.id.au>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>

This switches the clocksource to TIMER2 like the Moxart driver
does. Mainly to make it more similar to the Moxart/Aspeed driver
but also because it seems more neat to use the timers in order:
use timer 1, then timer 2.

Cc: Joel Stanley <joel@jms.id.au>
Tested-by: NJonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>

This switches the drivers to use the bitops BIT() macro
to define bits.

Cc: Joel Stanley <joel@jms.id.au>
Tested-by: NJonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>

This converts the Faraday FTTMR010 to use the state container
design pattern. Take some care to handle the state container
and free:ing of resources as has been done in the Moxa driver.

Cc: Joel Stanley <joel@jms.id.au>
Tested-by: NJonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>

The Gemini now has a proper clock driver and a proper PCLK
assigned in its device tree. Drop the Gemini-specific hacks
to look up the system speed and rely on the clock framework
like everyone else.

Cc: Joel Stanley <joel@jms.id.au>
Tested-by: NJonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>

This merges the Moxa and FTTMR010 device tree bindings into the
Faraday binding document to avoid confusion.

The FTTMR010 is the IP block used by these SoCs, in vanilla
or modified variant.

The Aspeed variant is modified such that it is no longer fully
register-compatible with FTTMR010 so for this reason it is not
listed with two compatible strings, instead just one.

Cc: Joel Stanley <joel@jms.id.au>
Tested-by: NJonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Acked-by: NRob Herring <robh@kernel.org>
Acked-by: NJoel Stanley <joel@jms.id.au>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>

We need to also prepare and enable the clock we are using to get
the right reference count and avoid it being shut off.
Tested-by: NJonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>

The merging of a number of clocksource drivers into fttmr010 means we
require clock-names to be specified in the Aspeed timer node, else the
clocksource fails to probe and boot hangs.
Signed-off-by: NAndrew Jeffery <andrew@aj.id.au>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>

All required callbacks are in place. Switch the alarm timer based posix
interval timer callbacks to the common implementation and remove the
incorrect private implementation.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211657.825471962@linutronix.de

Preparatory change to utilize the common posix timer mechanisms.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211657.747567162@linutronix.de

Preparatory change to utilize the common posix timer mechanisms.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211657.670026824@linutronix.de

Preparatory change to utilize the common posix timer mechanisms.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211657.592676753@linutronix.de

Preparatory change to utilize the common posix timer mechanisms.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211657.513694229@linutronix.de

Preparatory change to utilize the common posix timer mechanisms.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211657.434598989@linutronix.de

Replace the hrtimer calls by calls to the new try_to_cancel()/arm() kclock
callbacks and move the hrtimer specific implementation into the
corresponding callback functions.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211657.355396667@linutronix.de

Add timer_try_to_cancel() and timer_arm() callbacks to kclock which allow
to make common_timer_set() usable by both hrtimer and alarmtimer based
clocks.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211657.278022962@linutronix.de

Zero out the settings struct in the common code so the callbacks do not
have to do it themself.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211657.200870713@linutronix.de

Replace the hrtimer calls by calls to the new forward/remaining kclock
callbacks and move the hrtimer specific implementation into the
corresponding callback functions.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211657.121437232@linutronix.de

Add two callbacks to kclock which allow using common_)timer_get() for both
hrtimer and alarm timer based clocks.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211657.044915536@linutronix.de

Keep track of the activation state of posix timers. This is a preparatory
change for making common_timer_get() usable by both hrtimer and alarm timer
implementations.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211656.967783982@linutronix.de

Use the new timer_rearm() callback to replace the conditional hardcoded
calls into the hrtimer and cpu timer code.

This allows later to bring the same logic to alarmtimers.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211656.889661919@linutronix.de

That function is a misnomer. Rename it with a proper prefix to
posixtimer_rearm().
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211656.811362578@linutronix.de

Add a timer_rearm() callback which is used to make the rescheduling of
posix interval timers independent of the underlying clock implementation.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211656.732632167@linutronix.de

Having the k_clock pointer in the k_itimer struct avoids the lookup in
several code pathes and makes the next steps of unification of the hrtimer
and alarmtimer based posix timers simpler.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211656.641222072@linutronix.de

Preparatory patch to unify the alarm timer and hrtimer based posix interval
timer handling.

The interval is used as a criteria for rearming decisions so moving it out
of the clock specific data structures allows later unification.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211656.563922908@linutronix.de

hrtimer based posix-timers and posix-cpu-timers handle the update of the
rearming and overflow related status fields differently.

Move that update to the common rearming code.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211656.484936964@linutronix.de

None of these declarations is required outside of kernel/time. Move them to
an internal header.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20170530211656.394803853@linutronix.de

As a preparation for further changes, cleanup the formatting of the
k_itimer structure and add kernel doc comments.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211656.316574129@linutronix.de

Move it below the actual implementations as there are new callbacks coming
which would require even more forward declarations.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211656.238209952@linutronix.de

The only user of this facility is ptp_clock, which does not implement any of
those functions.

Remove them to prevent accidental users. Especially the interval timer
interfaces are now more or less impossible to implement because the
necessary infrastructure has been confined to the core code. Aside of that
it's really complex to make these callbacks implemented according to spec
as the alarm timer implementation demonstrates. If at all then a nanosleep
callback might be a reasonable extension. For now keep just what ptp_clock
needs.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211656.145036286@linutronix.de

Since the removal of the mmtimer driver the export is not longer needed.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211656.052744418@linutronix.de

Having a IF_ENABLED(CONFIG_POSIX_TIMERS) inside of a
#ifdef CONFIG_POSIX_TIMERS section is pointless.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211655.975218056@linutronix.de

Pick up urgent fixes to avoid conflicts.

The alarmtimer code has another source of potentially rearming itself too
fast. Interval timers with a very samll interval have a similar CPU hog
effect as the previously fixed overflow issue.

The reason is that alarmtimers do not implement the normal protection
against this kind of problem which the other posix timer use:

  timer expires -> queue signal -> deliver signal -> rearm timer

This scheme brings the rearming under scheduler control and prevents
permanently firing timers which hog the CPU.

Bringing this scheme to the alarm timer code is a major overhaul because it
lacks all the necessary mechanisms completely.

So for a quick fix limit the interval to one jiffie. This is not
problematic in practice as alarmtimers are usually backed by an RTC for
suspend which have 1 second resolution. It could be therefor argued that
the resolution of this clock should be set to 1 second in general, but
that's outside the scope of this fix.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kostya Serebryany <kcc@google.com>
Cc: syzkaller <syzkaller@googlegroups.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20170530211655.896767100@linutronix.de

Andrey reported a alartimer related RCU stall while fuzzing the kernel with
syzkaller.

The reason for this is an overflow in ktime_add() which brings the
resulting time into negative space and causes immediate expiry of the
timer. The following rearm with a small interval does not bring the timer
back into positive space due to the same issue.

This results in a permanent firing alarmtimer which hogs the CPU.

Use ktime_add_safe() instead which detects the overflow and clamps the
result to KTIME_SEC_MAX.
Reported-by: NAndrey Konovalov <andreyknvl@google.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kostya Serebryany <kcc@google.com>
Cc: syzkaller <syzkaller@googlegroups.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20170530211655.802921648@linutronix.de