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.
Change-Id: I43906fa7d083a2c611c2047e15c34d68bb047ac7
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>
Git-commit: 37f637767a82907efedda78d3ff405c34020075
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
[tsoni@codeaurora.org: Fixed trivial merge conflicts]
Signed-off-by: Trilok Soni <tsoni@codeaurora.org>
Add macros to describe the bitfields in the ARM architected timer
control register to make code easy to understand.
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
Git-commit: 28061758dc83df445a05af347b5ce55ccd968c03
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Ian Maund <imaund@codeaurora.org>
We have some users of the physical counter reading function, and
they need to work when either the cp15 or mmio timers are present
in any configuration. Bring back the functionality and expose it
to drivers so that the RPM code and SMEM code have proper global
timestamps to communicate with other processors.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
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>
Switching between reading the virtual or physical counters is
problematic, as some core code wants a view of time before we're fully
set up. Using a function pointer and switching the source after the
first read can make time appear to go backwards, and having a check in
the read function is an unfortunate block on what we want to be a fast
path.
Instead, this patch makes us always use the virtual counters. If we're a
guest, or don't have hyp mode, we'll use the virtual timers, and as such
don't care about CNTVOFF as long as it doesn't change in such a way as
to make time travel backwards. If we do have hyp mode, and might be a
KVM host, we have to use the physical timers, and require CNTVOFF to be
zero so as to have a consistent view of time between the physical timers
and virtual counters.
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>
Cc: Rob Herring <rob.herring@calxeda.com>
These continue the multiplatform support for exynos, adding support
for building most of the essential drivers (clocksource, clk, irqchip)
when combined with other platforms. As a result, it should become
really easy to add full multiplatform exynos support in 3.11, although
we don't yet enable it for 3.10.
The changes were not included in the earlier multiplatform series
in order to avoid clashes with the other Exynos updates.
This also includes work from Tomasz Figa to fix the pwm clocksource
code on Exynos, which is not strictly required for multiplatform,
but related to the other patches in this set and needed as a bug
fix for at least one board.
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Merge tag 'multiplatform-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull late ARM Exynos multiplatform changes from Arnd Bergmann:
"These continue the multiplatform support for exynos, adding support
for building most of the essential drivers (clocksource, clk, irqchip)
when combined with other platforms. As a result, it should become
really easy to add full multiplatform exynos support in 3.11, although
we don't yet enable it for 3.10.
The changes were not included in the earlier multiplatform series in
order to avoid clashes with the other Exynos updates.
This also includes work from Tomasz Figa to fix the pwm clocksource
code on Exynos, which is not strictly required for multiplatform, but
related to the other patches in this set and needed as a bug fix for
at least one board."
* tag 'multiplatform-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (22 commits)
ARM: dts: exynops4210: really add universal_c210 dts
ARM: dts: exynos4210: Add basic dts file for universal_c210 board
ARM: dts: exynos4: Add node for PWM device
ARM: SAMSUNG: Do not register legacy timer interrupts on Exynos
clocksource: samsung_pwm_timer: Work around rounding errors in clockevents core
clocksource: samsung_pwm_timer: Correct programming of clock events
clocksource: samsung_pwm_timer: Use proper clockevents max_delta
clocksource: samsung_pwm_timer: Add support for non-DT platforms
clocksource: samsung_pwm_timer: Drop unused samsung_pwm struct
clocksource: samsung_pwm_timer: Keep all driver data in a structure
clocksource: samsung_pwm_timer: Make PWM spinlock global
clocksource: samsung_pwm_timer: Let platforms select the driver
Documentation: Add device tree bindings for Samsung PWM timers
clocksource: add samsung pwm timer driver
irqchip: exynos: look up irq using irq_find_mapping
irqchip: exynos: pass irq_base from platform
irqchip: exynos: localize irq lookup for ATAGS
irqchip: exynos: allocate combiner_data dynamically
irqchip: exynos: pass max combiner number to combiner_init
ARM: exynos: add missing properties for combiner IRQs
...
This patch extends the driver to support platforms that still use legacy
ATAGS-based boot, without device tree, by providing an exported function
that can be used from platform code to initialize the clocksource.
Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
This patch removes the unused samsung_pwm struct from public header.
Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
This patch makes the PWM spinlock global and exports it to allow using
it in Samsung PWM driver (will be reworked to use proper synchronization
in further patches).
Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
This adds a new clocksource driver for the PWM timer that is
present in most Samsung SoCs, based on the existing driver in
arch/arm/plat-samsung/samsung-time.c and many changes implemented by
Tomasz Figa.
Originally, the conversion of all Samsung machines to the new driver was
planned for 3.10, but that work ended up being too late and too invasive
just before the merge window.
Unfortunately, other changes in the Exynos platform resulted in some
Exynos4 setups, particularly the Universal C210 board to be broken. In
order to fix that with minimum risk, so we now leave the existing pwm
clocksource driver in place for all older platforms and use the new
driver only for device tree enabled boards. This way, we can get the
broken machines running again using DT descriptions.
All clocksource changes were implemented by Tomasz, while the DT
registration was rewritten by Arnd.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Tomasz Figa <t.figa@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
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>
This adds core architecture support for Imagination's Meta processor
cores, followed by some later miscellaneous arch/metag cleanups and
fixes which I kept separate to ease review:
- Support for basic Meta 1 (ATP) and Meta 2 (HTP) core architecture
- A few fixes all over, particularly for symbol prefixes
- A few privilege protection fixes
- Several cleanups (setup.c includes, split out a lot of metag_ksyms.c)
- Fix some missing exports
- Convert hugetlb to use vm_unmapped_area()
- Copy device tree to non-init memory
- Provide dma_get_sgtable()
Signed-off-by: James Hogan <james.hogan@imgtec.com>
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Merge tag 'metag-v3.9-rc1-v4' of git://git.kernel.org/pub/scm/linux/kernel/git/jhogan/metag
Pull new ImgTec Meta architecture from James Hogan:
"This adds core architecture support for Imagination's Meta processor
cores, followed by some later miscellaneous arch/metag cleanups and
fixes which I kept separate to ease review:
- Support for basic Meta 1 (ATP) and Meta 2 (HTP) core architecture
- A few fixes all over, particularly for symbol prefixes
- A few privilege protection fixes
- Several cleanups (setup.c includes, split out a lot of
metag_ksyms.c)
- Fix some missing exports
- Convert hugetlb to use vm_unmapped_area()
- Copy device tree to non-init memory
- Provide dma_get_sgtable()"
* tag 'metag-v3.9-rc1-v4' of git://git.kernel.org/pub/scm/linux/kernel/git/jhogan/metag: (61 commits)
metag: Provide dma_get_sgtable()
metag: prom.h: remove declaration of metag_dt_memblock_reserve()
metag: copy devicetree to non-init memory
metag: cleanup metag_ksyms.c includes
metag: move mm/init.c exports out of metag_ksyms.c
metag: move usercopy.c exports out of metag_ksyms.c
metag: move setup.c exports out of metag_ksyms.c
metag: move kick.c exports out of metag_ksyms.c
metag: move traps.c exports out of metag_ksyms.c
metag: move irq enable out of irqflags.h on SMP
genksyms: fix metag symbol prefix on crc symbols
metag: hugetlb: convert to vm_unmapped_area()
metag: export clear_page and copy_page
metag: export metag_code_cache_flush_all
metag: protect more non-MMU memory regions
metag: make TXPRIVEXT bits explicit
metag: kernel/setup.c: sort includes
perf: Enable building perf tools for Meta
metag: add boot time LNKGET/LNKSET check
metag: add __init to metag_cache_probe()
...
Add time keeping code for metag. Meta hardware threads have 2 timers.
The background timer (TXTIMER) is used as a free-running time base, and
the interrupt timer (TXTIMERI) is used for the timer interrupt. Both
counters traditionally count at approximately 1MHz.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes:
In file included from arch/arm/include/asm/arch_timer.h:10:0,
from arch/arm/mach-shmobile/timer.c:23:
include/clocksource/arm_arch_timer.h:56:28: warning: 'arch_timer_get_timecounter' defined but not used [-Wunused-function]
Signed-off-by: Olof Johansson <olof@lixom.net>
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>
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>
This patch adds support for the ARM generic timers with A64 instructions
for accessing the timer registers. It uses the physical counter as the
clock source and the virtual counter as sched_clock.
The timer frequency can be specified via DT or read from the CNTFRQ_EL0
register. The physical counter is also accessible from user space
allowing fast gettimeofday() implementation.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Will Deacon
Sudeep KarkadaNagesha
Stephen Boyd
Mark Rutland
Linus Torvalds
Tomasz Figa
Rob Herring
James Hogan
Olof Johansson
Marc Zyngier