Pull in fixes from Daniel Lezcano:
- Fix the vt8500 timer leading to a system lock up when dealing with too
small delta (Roman Volkov)
- Select the CLKSRC_MMIO when the fsl_ftm_timer is enabled with COMPILE_TEST
(Daniel Lezcano)
- Prevent to compile timers using the 'iomem' API when the architecture has
not HAS_IOMEM set (Richard Weinberger)
The vt8500 clocksource driver declares itself as capable to handle the
minimum delay of 4 cycles by passing the value into
clockevents_config_and_register(). The vt8500_timer_set_next_event()
requires the passed cycles value to be at least 16. The impact is that
userspace hangs in nanosleep() calls with small delay intervals.
This problem is reproducible in Linux 4.2 starting from:
c6eb3f70d4 ('hrtimer: Get rid of hrtimer softirq')
From Russell King, more detailed explanation:
"It's a speciality of the StrongARM/PXA hardware. It takes a certain
number of OSCR cycles for the value written to hit the compare registers.
So, if a very small delta is written (eg, the compare register is written
with a value of OSCR + 1), the OSCR will have incremented past this value
before it hits the underlying hardware. The result is, that you end up
waiting a very long time for the OSCR to wrap before the event fires.
So, we introduce a check in set_next_event() to detect this and return
-ETIME if the calculated delta is too small, which causes the generic
clockevents code to retry after adding the min_delta specified in
clockevents_config_and_register() to the current time value.
min_delta must be sufficient that we don't re-trip the -ETIME check - if
we do, we will return -ETIME, forward the next event time, try to set it,
return -ETIME again, and basically lock the system up. So, min_delta
must be larger than the check inside set_next_event(). A factor of two
was chosen to ensure that this situation would never occur.
The PXA code worked on PXA systems for years, and I'd suggest no one
changes this mechanism without access to a wide range of PXA systems,
otherwise they're risking breakage."
Cc: stable@vger.kernel.org
Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: Alexey Charkov <alchark@gmail.com>
Signed-off-by: Roman Volkov <rvolkov@v1ros.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Migrate vt8500 driver to the new 'set-state' interface provided by
clockevents core, the earlier 'set-mode' interface is marked obsolete
now.
This also enables us to implement callbacks for new states of clockevent
devices, for example: ONESHOT_STOPPED.
Cc: Tony Prisk <linux@prisktech.co.nz>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
This patch removes the use of the IRQF_DISABLED flag.
It's a NOOP since 2.6.35 and it will be removed one day.
[dlezcano] : slightly changed the changelog
Signed-off-by: Michael Opdenacker <michael.opdenacker@free-electrons.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Instead of letting each driver call of_node_put do it centrally in the
loop that also calls the CLOCKSOURCE_OF_DECLARE callbacks. This is less
prone to error and also moves getting and putting the references into the
same function.
Consequently all respective of_node_put calls in drivers are removed.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: David Brown <davidb@codeaurora.org>
This ensures that a function pointer passed into CLOCKSOURCE_OF_DECLARE
takes the same arguments that we use for calling that function later.
Also fix the extraneous semicolon at end of the CLOCKSOURCE_OF_DECLARE
definition.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Rob Herring <rob.herring@calxeda.com>
In cases where we have multiple nodes of the same type, we may need the
node pointer to know which node was matched. Passing the node pointer
also keeps the init function from having to match the node a 2nd time.
Update bcm2835, vt8500, and tegra20 init functions for the new function
prototype. Further tegra20 clean-ups are in follow-up commit.
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Tony Prisk <linux@prisktech.co.nz>
Tested-by: Michal Simek <michal.simek@xilinx.com>
This patch converts arch-vt8500 to make use of CLKSRC_OF. Doing so
removes the need for include/linux/vt8500_timer.h as vt8500_timer_init
no longer needs to be visible outside vt8500_timer.c
Signed-off-by: Tony Prisk <linux@prisktech.co.nz>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
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Merge tag 'vt8500/timer' of git://server.prisktech.co.nz/git/linuxwmt into next/cleanup
From Tony Prisk:
Move arch-vt8500/timer.c to drivers/clocksource/vt8500-timer.c
* tag 'vt8500/timer' of git://server.prisktech.co.nz/git/linuxwmt:
timer: vt8500: Move timer code to drivers/clocksource
Signed-off-by: Olof Johansson <olof@lixom.net>
This patch moves arch-vt8500/timer.c into drivers/clocksource and
updates the necessary Kconfig/Makefile options.
Signed-off-by: Tony Prisk <linux@prisktech.co.nz>
Thomas Gleixner