linux/drivers/clocksource/arm_arch_timer.c, branch v3.16

clocksource: arch_arm_timer: Fix age-old arch timer C3STOP detection issue

2014-04-29T13:06:36Z

ARM arch timers are tightly coupled with the CPU logic and lose context on platform implementing HW power management when cores are powered down at run-time. Marking the arch timers as C3STOP regardless of power management capabilities causes issues on platforms with no power management, since in that case the arch timers cannot possibly enter states where the timer loses context at runtime and therefore can always be used as a high resolution clockevent device. In order to fix the C3STOP issue in a way compliant with how real HW works, this patch adds a boolean property to the arch timer bindings to define if the arch timer is managed by an always-on power domain. This power domain is present on all ARM platforms to date, and manages HW that must not be turned off, whatever the state of other HW components (eg power controller). On platforms with no power management capabilities, it is the only power domain present, which encompasses and manages power supply for all HW components in the system. If the timer is powered by the always-on power domain, the always-on property must be present in the bindings which means that the timer cannot be shutdown at runtime, so it is not a C3STOP clockevent device. If the timer binding does not contain the always-on property, the timer is assumed to be power-gateable, hence it must be defined as a C3STOP clockevent device. Cc: Daniel Lezcano Cc: Magnus Damm Cc: Marc Carino Cc: Mark Rutland Acked-by: Marc Zyngier Acked-by: Rob Herring Signed-off-by: Lorenzo Pieralisi Signed-off-by: Daniel Lezcano

clocksource: arch_timer: Set dynamic irq affinity on mmio clockevent

2014-03-11T22:04:39Z

Set the CLOCK_EVT_FEAT_DYNIRQ flag on the memory mapped clockevent so that we save power by waking up the CPU with the next event when this timer is used in broadcast mode. Signed-off-by: Stephen Boyd Signed-off-by: Daniel Lezcano

clocksource: arch_timer: Do not register arch_sys_counter twice

2013-10-16T06:30:03Z

Commit: 65cd4f6 ("arch_timer: Move to generic sched_clock framework") added code to register the arch_sys_counter in arch_timer_register(), but it is already registered in arch_counter_register(). This results in the timer being added to the clocksource list twice, therefore causing an infinite loop in the list. Remove the duplicate registration and register the scheduler clock after the original registration instead. This fixes a hang during boot on Tegra114 (Cortex-A15). [ While I've only tested this on Tegra114, I suspect the same hang during boot happens for all processors that use this clock source. ] Signed-off-by: Thierry Reding Acked-by: John Stultz Cc: Stephen Boyd Cc: Will Deacon Cc: Stephen Warren Cc: linux-arm-kernel@lists.infradead.org Cc: Daniel Lezcano Link: http://lkml.kernel.org/r/1381843911-31962-1-git-send-email-treding@nvidia.com Signed-off-by: Ingo Molnar

Merge branch 'fortglx/3.13/time' of git://git.linaro.org/people/jstultz/linux into timers/core

2013-10-10T04:25:23Z

Pull more timekeeping items for v3.13 from John Stultz: * Small cleanup in the clocksource code. * Fix for rtc-pl031 to let it work with alarmtimers. * Move arm64 to using the generic sched_clock framework & resulting cleanup in the generic sched_clock code. Signed-off-by: Ingo Molnar

arch_timer: Move to generic sched_clock framework

2013-10-09T23:54:10Z

Register with the generic sched_clock framework now that it supports 64 bits. This fixes two problems with the current sched_clock support for machines using the architected timers. First off, we don't subtract the start value from subsequent sched_clock calls so we can potentially start off with sched_clock returning gigantic numbers. Second, there is no support for suspend/resume handling so problems such as discussed in 6a4dae5 (ARM: 7565/1: sched: stop sched_clock() during suspend, 2012-10-23) can happen without this patch. Finally, it allows us to move the sched_clock setup into drivers clocksource out of the arch ports. Cc: Christopher Covington Cc: Catalin Marinas Acked-by: Will Deacon Signed-off-by: Stephen Boyd Signed-off-by: John Stultz

Merge branch 'timer_evtstrm' of git://linux-arm.org/linux-skn into clockevents/3.13

2013-10-03T14:13:51Z

Adds support to configure the rate and enable the event stream for architected timer. The event streams can be used to impose a timeout on a wfe, to safeguard against any programming error in case an expected event is not generated or even to implement wfe-based timeouts for userspace locking implementations. This feature can be disabled(enabled by default). Since the timer control register is reset to zero on warm boot, CPU PM notifier is added to save and restore the value. Signed-off-by: Daniel Lezcano

clocksource: arm_arch_timer: Use clocksource for suspend timekeeping

2013-10-02T09:43:17Z

The ARM architected timers keep counting during suspend so we can mark this clocksource with the CLOCK_SOURCE_SUSPEND_NONSTOP flag. This flag will indicate that this clocksource can be used for calculating suspend time and injecting sleep time into the timekeeping core. This should be more accurate than using an external RTC or architecture specific persistent clock. Cc: Mark Rutland Signed-off-by: Stephen Boyd Signed-off-by: Daniel Lezcano

drivers: clocksource: add CPU PM notifier for ARM architected timer

2013-09-26T08:48:24Z

Few control settings done in architected timer as part of initialisation can be lost when CPU enters deeper power states. They need to be restored when the CPU is (warm)reset again. This patch adds CPU PM notifiers to save the counter control register when entering low power modes and restore it when CPU exits low power. Reviewed-by: Catalin Marinas Reviewed-by: Lorenzo Pieralisi Reviewed-by: Will Deacon Acked-by: Olof Johansson Signed-off-by: Sudeep KarkadaNagesha

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

2013-09-26T08:48:00Z

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 Reviewed-by: Catalin Marinas Acked-by: Olof Johansson Signed-off-by: Will Deacon [sudeep: moving ARM/ARM64 changes into separate patches and adding Kconfig option] Signed-off-by: Sudeep KarkadaNagesha

Merge branch 'timers/clockevents-next' of git://git.linaro.org/people/dlezcano/clockevents into timers/core

2013-08-21T12:59:23Z

* Support for memory mapped arch_timers * Trivial fixes to the moxart timer code * Documentation updates Trivial conflicts in drivers/clocksource/arm_arch_timer.c. Fixed up the newly added __cpuinit annotations as well. Signed-off-by: Thomas Gleixner