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authorLinus Torvalds <torvalds@linux-foundation.org>2009-03-26 15:54:36 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-03-26 15:54:36 -0700
commit13220a94d35708d5378114e96ffcc88d0a74fe99 (patch)
treebe6530677d5f9536c7211e05ba012923e4c0b307 /kernel/time/clocksource.c
parent8690d8a9f6c2d5728a9c9f68231f1bb4de109e3a (diff)
parent08abe18af1f78ee80c3c3a5ac47c3e0ae0beadf6 (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.c76
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;