linux-toradex.git/drivers/clocksource/arm_arch_timer.c, branch v3.14.57 Linux kernel for Apalis and Colibri modules clocksource: arch_timer: Do not register arch_sys_counter twice 2013-10-16T06:30:03+00:00 Thierry Reding thierry.reding@gmail.com 2013-10-15T13:31:51+00:00 4a7d3e8a9939cf8073c247286d81cbe0ae48eba2 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 <treding@nvidia.com> Acked-by: John Stultz <john.stultz@linaro.org> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Will Deacon <will.deacon@arm.com> Cc: Stephen Warren <swarren@wwwdotorg.org> Cc: linux-arm-kernel@lists.infradead.org Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Link: http://lkml.kernel.org/r/1381843911-31962-1-git-send-email-treding@nvidia.com Signed-off-by: Ingo Molnar <mingo@kernel.org> 
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 <treding@nvidia.com>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: http://lkml.kernel.org/r/1381843911-31962-1-git-send-email-treding@nvidia.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Merge branch 'fortglx/3.13/time' of git://git.linaro.org/people/jstultz/linux into timers/core 2013-10-10T04:25:23+00:00 Ingo Molnar mingo@kernel.org 2013-10-10T04:25:23+00:00 8a749de5e32d2b72def93f7bd7a2745580d75872 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 <mingo@kernel.org> 
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 <mingo@kernel.org>
arch_timer: Move to generic sched_clock framework 2013-10-09T23:54:10+00:00 Stephen Boyd sboyd@codeaurora.org 2013-07-18T23:21:18+00:00 65cd4f6c99c1170bd0114dbd71b978012ea44d28 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 <cov@codeaurora.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: John Stultz <john.stultz@linaro.org> 
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 <cov@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Merge branch 'timer_evtstrm' of git://linux-arm.org/linux-skn into clockevents/3.13 2013-10-03T14:13:51+00:00 Daniel Lezcano daniel.lezcano@linaro.org 2013-10-03T14:13:51+00:00 191124efb4d6e5e47fe073b4b97350873523e88c 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 <daniel.lezcano@linaro.org> 
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 <daniel.lezcano@linaro.org>
clocksource: arm_arch_timer: Use clocksource for suspend timekeeping 2013-10-02T09:43:17+00:00 Stephen Boyd sboyd@codeaurora.org 2013-09-27T20:13:12+00:00 4fbcdc813fb9c0324fcff4c75414e717569d965e 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 <mark.rutland@arm.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> 
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 <mark.rutland@arm.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
drivers: clocksource: add CPU PM notifier for ARM architected timer 2013-09-26T08:48:24+00:00 Sudeep KarkadaNagesha sudeep.karkadanagesha@arm.com 2013-08-23T14:53:15+00:00 346e7480f1d4740b3d798da60f83f087ea6488b4 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 <catalin.marinas@arm.com> Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Reviewed-by: Will Deacon <will.deacon@arm.com> Acked-by: Olof Johansson <olof@lixom.net> Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com> 
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 <catalin.marinas@arm.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
drivers: clocksource: add support for ARM architected timer event stream 2013-09-26T08:48:00+00:00 Will Deacon will.deacon@arm.com 2013-08-23T14:32:29+00:00 037f637767a82907efedda78d3ff405c34020075 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> 
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>
Merge branch 'timers/clockevents-next' of git://git.linaro.org/people/dlezcano/clockevents into timers/core 2013-08-21T12:59:23+00:00 Thomas Gleixner tglx@linutronix.de 2013-08-21T12:59:23+00:00 cfb6d656d569510ac9239583ce09e4c92ad54719 * 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 <tglx@linutronix.de> 
* 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 <tglx@linutronix.de>
clocksource: arch_timer: Add support for memory mapped timers 2013-07-31T23:13:37+00:00 Stephen Boyd sboyd@codeaurora.org 2013-07-18T23:59:32+00:00 220069945b298d3998c6598b081c466dca259929 Add support for the memory mapped timers by filling in the read/write functions and adding some parsing code. Note that we only register one clocksource, preferring the cp15 based clocksource over the mmio one. To keep things simple we register one global clockevent. This covers the case of UP and SMP systems with only mmio hardware and systems where the memory mapped timers are used as the broadcast timer in low power modes. The DT binding allows for per-CPU memory mapped timers in case we want to support that in the future, but the code isn't added here. We also don't do much for hypervisor support, although it should be possible to support it by searching for at least two frames where one frame has the virtual capability and then updating KVM timers to support it. Cc: Mark Rutland <mark.rutland@arm.com> Cc: Marc Zyngier <Marc.Zyngier@arm.com> Cc: Rob Herring <robherring2@gmail.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Acked-by: Mark Rutland <mark.rutland@arm.com> 
Add support for the memory mapped timers by filling in the
read/write functions and adding some parsing code. Note that we
only register one clocksource, preferring the cp15 based
clocksource over the mmio one.

To keep things simple we register one global clockevent. This
covers the case of UP and SMP systems with only mmio hardware and
systems where the memory mapped timers are used as the broadcast
timer in low power modes.

The DT binding allows for per-CPU memory mapped timers in case we
want to support that in the future, but the code isn't added
here. We also don't do much for hypervisor support, although it
should be possible to support it by searching for at least two
frames where one frame has the virtual capability and then
updating KVM timers to support it.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <Marc.Zyngier@arm.com>
Cc: Rob Herring <robherring2@gmail.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
clocksource: arch_timer: Push the read/write wrappers deeper 2013-07-31T23:13:37+00:00 Stephen Boyd sboyd@codeaurora.org 2013-07-18T23:59:31+00:00 60faddf6eb3aba16068032bdcf35e18ace4bfb21 We're going to introduce support to read and write the memory mapped timer registers in the next patch, so push the cp15 read/write functions one level deeper. This simplifies the next patch and makes it clearer what's going on. Cc: Mark Rutland <mark.rutland@arm.com> Cc: Marc Zyngier <Marc.Zyngier@arm.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Acked-by: Mark Rutland <mark.rutland@arm.com> 
We're going to introduce support to read and write the memory
mapped timer registers in the next patch, so push the cp15
read/write functions one level deeper. This simplifies the next
patch and makes it clearer what's going on.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <Marc.Zyngier@arm.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>