Author: ian
Date: Fri Feb 15 18:30:32 2013
New Revision: 246845
URL: http://svnweb.freebsd.org/changeset/base/246845
Log:
Add PPS_CANWAIT support for time_pps_fetch(). This adds support for all three
blocking modes described in section 3.4.3 of RFC 2783, allowing the caller
to retrieve the most recent values without blocking, to block for a specified
time, or to block forever.
Reviewed by: discussion on hackers@
Modified:
head/sys/kern/kern_tc.c
Modified: head/sys/kern/kern_tc.c
==============================================================================
--- head/sys/kern/kern_tc.c Fri Feb 15 17:22:57 2013 (r246844)
+++ head/sys/kern/kern_tc.c Fri Feb 15 18:30:32 2013 (r246845)
@@ -1446,6 +1446,50 @@ SYSCTL_PROC(_kern_timecounter, OID_AUTO,
* RFC 2783 PPS-API implementation.
*/
+static int
+pps_fetch(struct pps_fetch_args *fapi, struct pps_state *pps)
+{
+ int err, timo;
+ pps_seq_t aseq, cseq;
+ struct timeval tv;
+
+ if (fapi->tsformat && fapi->tsformat != PPS_TSFMT_TSPEC)
+ return (EINVAL);
+
+ /*
+ * If no timeout is requested, immediately return whatever values were
+ * most recently captured. If timeout seconds is -1, that's a request
+ * to block without a timeout. WITNESS won't let us sleep forever
+ * without a lock (we really don't need a lock), so just repeatedly
+ * sleep a long time.
+ */
+ if (fapi->timeout.tv_sec || fapi->timeout.tv_nsec) {
+ if (fapi->timeout.tv_sec == -1)
+ timo = 0x7fffffff;
+ else {
+ tv.tv_sec = fapi->timeout.tv_sec;
+ tv.tv_usec = fapi->timeout.tv_nsec / 1000;
+ timo = tvtohz(&tv);
+ }
+ aseq = pps->ppsinfo.assert_sequence;
+ cseq = pps->ppsinfo.clear_sequence;
+ while (aseq == pps->ppsinfo.assert_sequence &&
+ cseq == pps->ppsinfo.clear_sequence) {
+ err = tsleep(pps, PCATCH, "ppsfch", timo);
+ if (err == EWOULDBLOCK && fapi->timeout.tv_sec == -1) {
+ continue;
+ } else if (err != 0) {
+ return (err);
+ }
+ }
+ }
+
+ pps->ppsinfo.current_mode = pps->ppsparam.mode;
+ fapi->pps_info_buf = pps->ppsinfo;
+
+ return (0);
+}
+
int
pps_ioctl(u_long cmd, caddr_t data, struct pps_state *pps)
{
@@ -1485,13 +1529,7 @@ pps_ioctl(u_long cmd, caddr_t data, stru
return (0);
case PPS_IOC_FETCH:
fapi = (struct pps_fetch_args *)data;
- if (fapi->tsformat && fapi->tsformat != PPS_TSFMT_TSPEC)
- return (EINVAL);
- if (fapi->timeout.tv_sec || fapi->timeout.tv_nsec)
- return (EOPNOTSUPP);
- pps->ppsinfo.current_mode = pps->ppsparam.mode;
- fapi->pps_info_buf = pps->ppsinfo;
- return (0);
+ return (pps_fetch(fapi, pps));
#ifdef FFCLOCK
case PPS_IOC_FETCH_FFCOUNTER:
fapi_ffc = (struct pps_fetch_ffc_args *)data;
@@ -1540,7 +1578,7 @@ pps_ioctl(u_long cmd, caddr_t data, stru
void
pps_init(struct pps_state *pps)
{
- pps->ppscap |= PPS_TSFMT_TSPEC;
+ pps->ppscap |= PPS_TSFMT_TSPEC | PPS_CANWAIT;
if (pps->ppscap & PPS_CAPTUREASSERT)
pps->ppscap |= PPS_OFFSETASSERT;
if (pps->ppscap & PPS_CAPTURECLEAR)
@@ -1680,6 +1718,9 @@ pps_event(struct pps_state *pps, int eve
hardpps(tsp, ts.tv_nsec + 1000000000 * ts.tv_sec);
}
#endif
+
+ /* Wakeup anyone sleeping in pps_fetch(). */
+ wakeup(pps);
}
/*
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