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path: root/include/linux/clocksource.h
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2009-05-02clocksource: setup mult_orig in clocksource_enable()Magnus Damm1-1/+9
Setup clocksource mult_orig in clocksource_enable(). Clocksource drivers can save power by using keeping the device clock disabled while the clocksource is unused. In practice this means that the enable() and disable() callbacks perform clk_enable() and clk_disable(). The enable() callback may also use clk_get_rate() to get the clock rate from the clock framework. This information can then be used to calculate the shift and mult variables. Currently the mult_orig variable is setup from mult at registration time only. This is conflicting with the above case since the clock is disabled and the mult variable is not yet calculated at the time of registration. Moving the mult_orig setup code to clocksource_enable() allows us to both handle the common case with no enable() callback and the mult-changed-after-enable() case. [ Impact: allow dynamic clock source usage ] Signed-off-by: Magnus Damm <damm@igel.co.jp> LKML-Reference: <20090501054546.8193.10688.sendpatchset@rx1.opensource.se> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-04-21clocksource: add enable() and disable() callbacksMagnus Damm1-0/+31
Add enable() and disable() callbacks for clocksources. This allows us to put unused clocksources in power save mode. The functions clocksource_enable() and clocksource_disable() wrap the callbacks and are inserted in the timekeeping code to enable before use and disable after switching to a new clocksource. Signed-off-by: Magnus Damm <damm@igel.co.jp> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-21clocksource: pass clocksource to read() callbackMagnus Damm1-3/+3
Pass clocksource pointer to the read() callback for clocksources. This allows us to share the callback between multiple instances. [hugh@veritas.com: fix powerpc build of clocksource pass clocksource mods] [akpm@linux-foundation.org: cleanup] Signed-off-by: Magnus Damm <damm@igel.co.jp> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-15clocksource: allow usage independent of timekeeping.cPatrick Ohly1-0/+101
So far struct clocksource acted as the interface between time/timekeeping.c and hardware. This patch generalizes the concept so that a similar interface can also be used in other contexts. For that it introduces new structures and related functions *without* touching the existing struct clocksource. The reasons for adding these new structures to clocksource.[ch] are * the APIs are clearly related * struct clocksource could be cleaned up to use the new structs * avoids proliferation of files with similar names (timesource.h? timecounter.h?) As outlined in the discussion with John Stultz, this patch adds * struct cyclecounter: stateless API to hardware which counts clock cycles * struct timecounter: stateful utility code built on a cyclecounter which provides a nanosecond counter * only the function to read the nanosecond counter; deltas are used internally and not exposed to users of timecounter The code does no locking of the shared state. It must be called at least as often as the cycle counter wraps around to detect these wrap arounds. Both is the responsibility of the timecounter user. Acked-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Patrick Ohly <patrick.ohly@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-08-21clocksource: introduce CLOCK_MONOTONIC_RAWJohn Stultz1-0/+3
In talking with Josip Loncaric, and his work on clock synchronization (see btime.sf.net), he mentioned that for really close synchronization, it is useful to have access to "hardware time", that is a notion of time that is not in any way adjusted by the clock slewing done to keep close time sync. Part of the issue is if we are using the kernel's ntp adjusted representation of time in order to measure how we should correct time, we can run into what Paul McKenney aptly described as "Painting a road using the lines we're painting as the guide". I had been thinking of a similar problem, and was trying to come up with a way to give users access to a purely hardware based time representation that avoided users having to know the underlying frequency and mask values needed to deal with the wide variety of possible underlying hardware counters. My solution is to introduce CLOCK_MONOTONIC_RAW. This exposes a nanosecond based time value, that increments starting at bootup and has no frequency adjustments made to it what so ever. The time is accessed from userspace via the posix_clock_gettime() syscall, passing CLOCK_MONOTONIC_RAW as the clock_id. Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-21clocksource: keep track of original clocksource frequencyJohn Stultz1-4/+7
The clocksource frequency is represented by clocksource->mult/2^(clocksource->shift). Currently, when NTP makes adjustments to the clock frequency, they are made directly to the mult value. This has the drawback that once changed, we cannot know what the orignal mult value was, or how much adjustment has been applied. This property causes problems in calculating proper ntp intervals when switching back and forth between clocksources. This patch separates the current mult value into a mult and mult_orig pair. The mult_orig value stays constant, while the ntp clocksource adjustments are done only to the mult value. This allows for correct ntp interval calculation and additionally lays the groundwork for a new notion of time, what I'm calling the monotonic-raw time, which is introduced in a following patch. Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-01ntp: handle leap second via timerRoman Zippel1-0/+2
Remove the leap second handling from second_overflow(), which doesn't have to check for it every second anymore. With CONFIG_NO_HZ this also makes sure the leap second is handled close to the full second. Additionally this makes it possible to abort a leap second properly by resetting the STA_INS/STA_DEL status bits. Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Cc: john stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-17kgdb: clocksource watchdogJason Wessel1-0/+1
In order to not trip the clocksource watchdog, kgdb must touch the clocksource watchdog on the return to normal system run state. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-01-30clocksource: add unregister function to disable unusable clocksourcesThomas Gleixner1-0/+1
On x86 the PIT might become an unusable clocksource. Add an unregister function to provide a possibilty to remove the PIT from the list of available clock sources. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-01-30clocksource: make CLOCKSOURCE_MASK bullet-proofAtsushi Nemoto1-1/+1
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2007-10-18Fix discrepancy between VDSO based gettimeofday() and sys_gettimeofday().Tony Breeds1-0/+5
On platforms that copy sys_tz into the vdso (currently only x86_64, soon to include powerpc), it is possible for the vdso to get out of sync if a user calls (admittedly unusual) settimeofday(NULL, ptr). This patch adds a hook for architectures that set CONFIG_GENERIC_TIME_VSYSCALL to ensure when sys_tz is updated they can also updatee their copy in the vdso. Signed-off-by: Tony Breeds <tony@bakeyournoodle.com> Cc: Andi Kleen <ak@suse.de> Cc: Tony Luck <tony.luck@intel.com> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-20[IA64] Convert to generic timekeeping/clocksourceTony Luck1-0/+6
This is a merge of Peter Keilty's initial patch (which was revived by Bob Picco) for this with Hidetoshi Seto's fixes and scaling improvements. Acked-by: Bob Picco <bob.picco@hp.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
2007-05-09clocksource: fix resume logicThomas Gleixner1-0/+3
We need to make sure that the clocksources are resumed, when timekeeping is resumed. The current resume logic does not guarantee this. Add a resume function pointer to the clocksource struct, so clocksource drivers which need to reinitialize the clocksource can provide a resume function. Add a resume function, which calls the maybe available clocksource resume functions and resets the watchdog function, so a stable TSC can be used accross suspend/resume. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Cc: Andi Kleen <ak@suse.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08time: SMP friendly alignment of struct clocksourceEric Dumazet1-2/+13
struct clocksource is a critical data structure. Most of its fields are read only, some of them are heavily modified at each timer interrupt. It makes sense to separate those fields and make sure they all share one cache line, or at least the minimum for machines with small cache lines. [akpm@linux-foundation.org: build fix] Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Acked-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-16[PATCH] generic: vsyscall-gtod support for GENERIC_TIMEjohn stultz1-0/+10
Provides generic infrastructure for vsyscall-gtod. [akpm@osdl.org: cleanup] Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andi Kleen <ak@muc.de> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-16[PATCH] clocksource: Add verification (watchdog) helperThomas Gleixner1-2/+13
The TSC needs to be verified against another clocksource. Instead of using hardwired assumptions of available hardware, provide a generic verification mechanism. The verification uses the best available clocksource and handles the usability for high resolution timers / dynticks of the clocksource which needs to be verified. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-16[PATCH] clocksource: Remove the update callbackThomas Gleixner1-2/+0
The clocksource code allows direct updates of the rating of a given clocksource now. Change TSC unstable tracking to use this interface and remove the update callback. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-16[PATCH] clocksource: replace is_continuous by a flag fieldThomas Gleixner1-2/+8
Using a flag filed allows to encode more than one information into a variable. Preparatory patch for the generic clocksource verification. [mingo@elte.hu: convert vmitime.c to the new clocksource flag] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-16[PATCH] Simplify the registration of clocksourcesThomas Gleixner1-3/+3
Enqueue clocksources in rating order to make selection of the clocksource easier. Also check the match with an user override at enqueue time. Preparatory patch for the generic clocksource verification. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-12-10[PATCH] clocksource: small cleanupDaniel Walker1-1/+1
Mostly changing alignment. Just some general cleanup. [akpm@osdl.org: build fix] Signed-off-by: Daniel Walker <dwalker@mvista.com> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26[PATCH] fix and optimize clock source updateRoman Zippel1-104/+9
This fixes the clock source updates in update_wall_time() to correctly track the time coming in via current_tick_length(). Optimize the fast paths to be as short as possible to keep the overhead low. Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Acked-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26[PATCH] generic-time: add macro to simplify/hide mask constantsJim Cromie1-0/+2
Add a CLOCKSOURCE_MASK macro to simplify initializing the mask for a struct clocksource, and use it to replace literal mask constants in the various clocksource drivers. Signed-off-by: Jim Cromie <jim.cromie@gmail.com> Acked-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26[PATCH] time: rename clocksource functionsjohn stultz1-7/+7
As suggested by Roman Zippel, change clocksource functions to use clocksource_xyz rather then xyz_clocksource to avoid polluting the namespace. Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26[PATCH] Time: Use clocksource abstraction for NTP adjustmentsjohn stultz1-0/+97
Instead of incrementing xtime by tick_nsec + ntp adjustments, use the clocksource abstraction to increment and scale time. Using the clocksource abstraction allows other clocksources to be used consistently in the face of late or lost ticks, while preserving the existing behavior via the jiffies clocksource. This removes the need to keep time_phase adjustments as we just use the current_tick_length() function as the NTP interface and accumulate time using shifted nanoseconds. The basics of this design was by Roman Zippel, however it is my own interpretation and implementation, so the credit should go to him and the blame to me. Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26[PATCH] Time: Clocksource Infrastructurejohn stultz1-0/+181
This introduces the clocksource management infrastructure. A clocksource is a driver-like architecture generic abstraction of a free-running counter. This code defines the clocksource structure, and provides management code for registering, selecting, accessing and scaling clocksources. Additionally, this includes the trivial jiffies clocksource, a lowest common denominator clocksource, provided mainly for use as an example. [hirofumi@mail.parknet.co.jp: Don't enable IRQ too early] Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Paul Mundt <lethal@linux-sh.org> Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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