linux.git/arch/arm/kernel/arch_timer.c, branch v3.10

ARM: convert arm/arm64 arch timer to use CLKSRC_OF init

2013-04-11T20:11:15+00:00

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 
Cc: Russell King 
Cc: Kukjin Kim 
Cc: Tony Lindgren 
Cc: Simon Horman 
Cc: Magnus Damm 
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: John Stultz 
Cc: Thomas Gleixner 
Cc: linux-samsung-soc@vger.kernel.org
Cc: linux-omap@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Acked-by: Santosh Shilimkar

ARM: arch_timer: use full 64-bit counter for sched_clock

2013-04-11T20:11:14+00:00

Only 32-bits of the arch timer were being used and wrapping was needlessly
being done in s/w. By using the full counter (56-64 bits), we don't need
to deal with wrapping and can simplify the implementation when using
arch timer.

Signed-off-by: Rob Herring

ARM: arch_timer: include linux/errno.h

2013-02-15T18:32:03+00:00

Patch 8a4da6e "arm: arch_timer: move core to drivers/clocksource"
moved a lot of code out of arch_timer.c, but ended up deleting
too much, which broke some configurations.

Obviously, include linux/errno.h is required to return error
values.

Without this patch, building allmodconfig results in:

arch/arm/kernel/arch_timer.c: In function 'arch_timer_sched_clock_init':
arch/arm/kernel/arch_timer.c:55:11: error: 'ENXIO' undeclared (first use in this function)
arch/arm/kernel/arch_timer.c:55:11: note: each undeclared identifier is reported only once for each function it appears in

Signed-off-by: Arnd Bergmann 
Acked-by: Mark Rutland 
Cc: Catalin Marinas 
Cc: Marc Zyngier

arm: arch_timer: move core to drivers/clocksource

2013-01-31T15:51:49+00:00

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 
Acked-by: Catalin Marinas 
Acked-by: Marc Zyngier

arm: arch_timer: add arch_counter_set_user_access

2013-01-31T15:51:39+00:00

Several bits in CNTKCTL reset to 0, including PL0VTEN. For architectures
using the generic timer which wish to have a fast gettimeofday vDSO
implementation, these bits must be set to 1 by the kernel. For
architectures without a vDSO, it's best to leave the bits set to 0 for
now to ensure that if and when support is added, it's implemented sanely
architecture wide.

As the bootloader might set PL0VTEN to a value that doesn't correspond
to that which the kernel prefers, we must explicitly set it to the
architecture port's preferred value.

This patch adds arch_counter_set_user_access, which sets the PL0 access
permissions to that required by the architecture. For arch/arm, this
currently means disabling all userspace access.

Signed-off-by: Mark Rutland 
Acked-by: Catalin Marinas

arm: arch_timer: divorce from local_timer api

2013-01-31T15:51:38+00:00

Currently, the arch_timer driver is tied to the arm port, as it relies
on code in arch/arm/smp.c to setup and teardown timers as cores are
hotplugged on and off. The timer is registered through an arm-specific
registration mechanism, preventing sharing the driver with the arm64
port.

This patch moves the driver to using a cpu notifier instead, making it
easier to port.

Signed-off-by: Mark Rutland 
Acked-by: Catalin Marinas 
Acked-by: Marc Zyngier 
Acked-by: Santosh Shilimkar

arm: arch_timer: factor out register accessors

2013-01-31T15:51:22+00:00

Currently the arch_timer register accessors are thrown together with
the main driver, preventing us from porting the driver to other
architectures.

This patch moves the register accessors into a header file, as with
the arm64 version. Constants required by the accessors are also moved.

Signed-off-by: Mark Rutland 
Acked-by: Catalin Marinas 
Acked-by: Marc Zyngier 
Acked-by: Santosh Shilimkar

arm: arch_timer: split cntfrq accessor

2013-01-31T15:51:22+00:00

The CNTFRQ register is not duplicated for physical and virtual timers,
and accessing it as if it were is confusing.

Instead, use a separate accessor which doesn't take the access type
as a parameter.

Signed-off-by: Mark Rutland 
Acked-by: Catalin Marinas 
Acked-by: Marc Zyngier 
Acked-by: Santosh Shilimkar

arm: arch_timer: standardise counter reading

2013-01-31T15:51:06+00:00

We're currently inconsistent with respect to our accesses to the
physical and virtual counters, mixing and matching the two.

This patch introduces and uses a function pointer for accessing the
correct counter based on whether we're using physical or virtual
interrupts. All current accesses to the counter accessors are redirected
through it.

When the driver is moved out to drivers/clocksource, there's the
possibility that code called before the timer code is initialised will
attempt to call arch_timer_read_counter (e.g. sched_clock for AArch64).
To avoid having to have to check whether the timer has been initialised
either in arch_timer_read_counter or one of it's callers, a default
implementation is assigned that simply returns 0.

Signed-off-by: Mark Rutland 
Acked-by: Catalin Marinas 
Cc: Marc Zyngier 
Cc: Santosh Shilimkar

arm: arch_timer: use u64/u32 for register data

2013-01-31T15:51:05+00:00

To ensure the correct size of types, use u64 for the return value of
arch_timer_get_cnt{p,v}ct, and u32 for arch_timer_rate, matching the
size of the registers these values are taken from. While we're changing
them anyway, simplify the implementation of arch_timer_get_cnt{p,v}ct.

Signed-off-by: Mark Rutland 
Acked-by: Catalin Marinas 
Acked-by: Marc Zyngier 
Acked-by: Santosh Shilimkar