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Add PPS_CANWAIT support for time_pps_fetch(). This adds support for all three

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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@
This commit is contained in:
Ian Lepore 2013-02-15 18:30:32 +00:00
parent 421ccedd26
commit a1137de941
1 changed files with 49 additions and 8 deletions
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57
sys/kern/kern_tc.c
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@ -1446,6 +1446,50 @@ SYSCTL_PROC(_kern_timecounter, OID_AUTO, choice, CTLTYPE_STRING | CTLFLAG_RD,
* 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, struct pps_state *pps)
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, struct pps_state *pps)
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 event)
hardpps(tsp, ts.tv_nsec + 1000000000 * ts.tv_sec);
}
#endif
/* Wakeup anyone sleeping in pps_fetch(). */
wakeup(pps);
}
/*