Will Deacon 8c06dc7aa1 drivers: clocksource: add support for ARM architected timer event stream ...

The ARM architected timer can generate events (used for waking up
CPUs executing the wfe instruction) at a frequency represented as a
power-of-2 divisor of the clock rate.

An event stream might be used:
- To implement wfe-based timeouts for userspace locking implementations.
- To impose a timeout on a wfe for safeguarding against any programming
  error in case an expected event is not generated.

This patch computes the event stream frequency aiming for a period
of 100us between events. It uses ARM/ARM64 specific backends to configure
and enable the event stream.

Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Will Deacon <will.deacon@arm.com>
[sudeep: moving ARM/ARM64 changes into separate patches
         and adding Kconfig option]
Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>

(cherry picked from commit 037f637767)
Signed-off-by: Alex Shi <alex.shi@linaro.org>

Conflicts:
	drivers/clocksource/Kconfig
	drivers/clocksource/arm_arch_timer.c

2014-04-28 13:59:00 +08:00

..

arm_arch_timer.h

drivers: clocksource: add support for ARM architected timer event stream

2014-04-28 13:59:00 +08:00

metag_generic.h

metag: Time keeping

2013-03-02 20:09:22 +00:00

samsung_pwm.h

clocksource: samsung_pwm_timer: Add support for non-DT platforms

2013-04-28 12:16:54 -07:00