ieee1394: cycle timer read extension for raw1394
This implements the simultaneous read of the isochronous cycle timer and
the system clock (in usecs). This allows to express the exact receive
time of an ISO packet as a system time with microsecond accuracy.
http://bugzilla.kernel.org/show_bug.cgi?id=7773
The counterpart patch for libraw1394 can be found at
http://thread.gmane.org/gmane.linux.kernel.firewire.devel/8934
Patch update (Stefan R.): Disable preemption and local interrupts.
Prevent integer overflow. Add paranoid error checks and kerneldoc to
hpsb_read_cycle_timer. Move it to other ieee1394_core high-level API
functions. Change comments. Adjust whitespace. Rename struct
_raw1394_cycle_timer.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Acked-by: Pieter Palmers <pieterp@joow.be>
Acked-by: Dan Dennedy <dan@dennedy.org>
diff --git a/drivers/ieee1394/ieee1394_core.h b/drivers/ieee1394/ieee1394_core.h
index 536ba3f..bd29d8e 100644
--- a/drivers/ieee1394/ieee1394_core.h
+++ b/drivers/ieee1394/ieee1394_core.h
@@ -127,6 +127,9 @@
* progress, 0 otherwise. */
int hpsb_reset_bus(struct hpsb_host *host, int type);
+int hpsb_read_cycle_timer(struct hpsb_host *host, u32 *cycle_timer,
+ u64 *local_time);
+
/*
* The following functions are exported for host driver module usage. All of
* them are safe to use in interrupt contexts, although some are quite