diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-03-26 15:54:36 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-03-26 15:54:36 -0700 |
| commit | 13220a94d35708d5378114e96ffcc88d0a74fe99 (patch) | |
| tree | be6530677d5f9536c7211e05ba012923e4c0b307 /kernel/time/clocksource.c | |
| parent | 8690d8a9f6c2d5728a9c9f68231f1bb4de109e3a (diff) | |
| parent | 08abe18af1f78ee80c3c3a5ac47c3e0ae0beadf6 (diff) | |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6: (1750 commits)
ixgbe: Allow Priority Flow Control settings to survive a device reset
net: core: remove unneeded include in net/core/utils.c.
e1000e: update version number
e1000e: fix close interrupt race
e1000e: fix loss of multicast packets
e1000e: commonize tx cleanup routine to match e1000 & igb
netfilter: fix nf_logger name in ebt_ulog.
netfilter: fix warning in ebt_ulog init function.
netfilter: fix warning about invalid const usage
e1000: fix close race with interrupt
e1000: cleanup clean_tx_irq routine so that it completely cleans ring
e1000: fix tx hang detect logic and address dma mapping issues
bridge: bad error handling when adding invalid ether address
bonding: select current active slave when enslaving device for mode tlb and alb
gianfar: reallocate skb when headroom is not enough for fcb
Bump release date to 25Mar2009 and version to 0.22
r6040: Fix second PHY address
qeth: fix wait_event_timeout handling
qeth: check for completion of a running recovery
qeth: unregister MAC addresses during recovery.
...
Manually fixed up conflicts in:
drivers/infiniband/hw/cxgb3/cxio_hal.h
drivers/infiniband/hw/nes/nes_nic.c
Diffstat (limited to 'kernel/time/clocksource.c')
| -rw-r--r-- | kernel/time/clocksource.c | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index ca89e1593f08..c46c931a7fe7 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -31,6 +31,82 @@ #include <linux/sched.h> /* for spin_unlock_irq() using preempt_count() m68k */ #include <linux/tick.h> +void timecounter_init(struct timecounter *tc, + const struct cyclecounter *cc, + u64 start_tstamp) +{ + tc->cc = cc; + tc->cycle_last = cc->read(cc); + tc->nsec = start_tstamp; +} +EXPORT_SYMBOL(timecounter_init); + +/** + * timecounter_read_delta - get nanoseconds since last call of this function + * @tc: Pointer to time counter + * + * When the underlying cycle counter runs over, this will be handled + * correctly as long as it does not run over more than once between + * calls. + * + * The first call to this function for a new time counter initializes + * the time tracking and returns an undefined result. + */ +static u64 timecounter_read_delta(struct timecounter *tc) +{ + cycle_t cycle_now, cycle_delta; + u64 ns_offset; + + /* read cycle counter: */ + cycle_now = tc->cc->read(tc->cc); + + /* calculate the delta since the last timecounter_read_delta(): */ + cycle_delta = (cycle_now - tc->cycle_last) & tc->cc->mask; + + /* convert to nanoseconds: */ + ns_offset = cyclecounter_cyc2ns(tc->cc, cycle_delta); + + /* update time stamp of timecounter_read_delta() call: */ + tc->cycle_last = cycle_now; + + return ns_offset; +} + +u64 timecounter_read(struct timecounter *tc) +{ + u64 nsec; + + /* increment time by nanoseconds since last call */ + nsec = timecounter_read_delta(tc); + nsec += tc->nsec; + tc->nsec = nsec; + + return nsec; +} +EXPORT_SYMBOL(timecounter_read); + +u64 timecounter_cyc2time(struct timecounter *tc, + cycle_t cycle_tstamp) +{ + u64 cycle_delta = (cycle_tstamp - tc->cycle_last) & tc->cc->mask; + u64 nsec; + + /* + * Instead of always treating cycle_tstamp as more recent + * than tc->cycle_last, detect when it is too far in the + * future and treat it as old time stamp instead. + */ + if (cycle_delta > tc->cc->mask / 2) { + cycle_delta = (tc->cycle_last - cycle_tstamp) & tc->cc->mask; + nsec = tc->nsec - cyclecounter_cyc2ns(tc->cc, cycle_delta); + } else { + nsec = cyclecounter_cyc2ns(tc->cc, cycle_delta) + tc->nsec; + } + + return nsec; +} +EXPORT_SYMBOL(timecounter_cyc2time); + /* XXX - Would like a better way for initializing curr_clocksource */ extern struct clocksource clocksource_jiffies; |
