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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>
(cherry picked from commit 346e7480f1d4740b3d798da60f83f087ea6488b4)
Signed-off-by: Alex Shi <alex.shi@linaro.org>
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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 037f637767a82907efedda78d3ff405c34020075)
Signed-off-by: Alex Shi <alex.shi@linaro.org>
Conflicts:
drivers/clocksource/Kconfig
drivers/clocksource/arm_arch_timer.c
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Hot-plugging with CONFIG_DEBUG_PREEMPT=y on a device with arm
architected timers causes a slew of "using smp_processor_id() in
preemptible" warnings:
BUG: using smp_processor_id() in preemptible [00000000] code: sh/111
caller is arch_timer_cpu_notify+0x14/0xc8
This happens because sometimes the cpu notifier,
arch_timer_cpu_notify(), is called in preemptible context and
other times in non-preemptible context but we use this_cpu_ptr()
to retrieve the clockevent in all cases. We're only going to
actually use the pointer in non-preemptible context though, so
push the this_cpu_ptr() access down into the cases to force the
checks to occur only in non-preemptible contexts.
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Acked-by: Marc Zyngier <Marc.Zyngier@arm.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Olof Johansson <olof@lixom.net>
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This converts arm and arm64 to use CLKSRC_OF DT based initialization for
the arch timer. A new function arch_timer_arch_init is added to allow for
arch specific setup.
This has a side effect of enabling sched_clock on omap5 and exynos5. There
should not be any reason not to use the arch timers for sched_clock.
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Simon Horman <horms@verge.net.au>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-samsung-soc@vger.kernel.org
Cc: linux-omap@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
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If we're booted in HYP mode, it is possible that we'll run some
kind of virtualized environment. In this case, it is a better to
switch to the physical timers, and leave the virtual timers to
guests.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
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The arch_timer driver supports a superset of the functionality of the
arm_generic driver, and is not tied to a particular arch.
This patch moves arm64 to use the arch_timer driver, gaining additional
functionality in doing so, and removes the (now unused) arm_generic
driver. Timer-related hooks specific to arm64 are moved into
arch/arm64/kernel/time.c.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
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The core functionality of the arch_timer driver is not directly tied to
anything under arch/arm, and can be split out.
This patch factors out the core of the arch_timer driver, so it can be
shared with other architectures. A couple of functions are added so
that architecture-specific code can interact with the driver without
needing to touch its internals.
The ARM_ARCH_TIMER config variable is moved out to
drivers/clocksource/Kconfig, existing uses in arch/arm are replaced with
HAVE_ARM_ARCH_TIMER, which selects it.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
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