char *xntimer_format_time(xnticks_t value, int periodic, char *buf, size_t bufsz)
{
unsigned long ms, us, ns;
char *p = buf;
xnticks_t s;
if (periodic) {
snprintf(buf, bufsz, "%Lut", value);
return buf;
}
if (value == 0 && bufsz > 1) {
strcpy(buf, "-");
return buf;
}
s = xnarch_divrem_billion(value, &ns);
us = ns / 1000;
ms = us / 1000;
us %= 1000;
if (s)
p += snprintf(p, bufsz, "%Lus", s);
if (ms || (s && us))
p += snprintf(p, bufsz - (p - buf), "%lums", ms);
if (us)
p += snprintf(p, bufsz - (p - buf), "%luus", us);
return buf;
}
int __wrap_clock_gettime(clockid_t clock_id, struct timespec *tp)
{
int err;
#ifdef XNARCH_HAVE_NONPRIV_TSC
if (clock_id == CLOCK_MONOTONIC && __pse51_sysinfo.tickval == 1) {
unsigned long long ns;
unsigned long rem;
ns = xnarch_tsc_to_ns(__xn_rdtsc());
tp->tv_sec = xnarch_divrem_billion(ns, &rem);
tp->tv_nsec = rem;
return 0;
}
#endif /* XNARCH_HAVE_NONPRIV_TSC */
err = -XENOMAI_SKINCALL2(__pse51_muxid,
__pse51_clock_gettime,
clock_id,
tp);
if (!err)
return 0;
errno = err;
return -1;
}
/**
* Read the host-synchronised realtime clock.
*
* Obtain the current time with NTP corrections from the Linux domain
*
* @param tp pointer to a struct timespec
*
* @retval 0 on success;
* @retval -1 if no suitable NTP-corrected clocksource is availabel
*
* @see
* <a href="http://www.opengroup.org/onlinepubs/000095399/functions/gettimeofday.html">
* Specification.</a>
*
*/
static int do_clock_host_realtime(struct timespec *tp)
{
#ifdef CONFIG_XENO_OPT_HOSTRT
cycle_t now, base, mask, cycle_delta;
unsigned long mult, shift, nsec, rem;
struct xnvdso_hostrt_data *hostrt_data;
unsigned int seq;
hostrt_data = get_hostrt_data();
BUG_ON(!hostrt_data);
if (unlikely(!hostrt_data->live))
return -1;
/*
* Note: Disabling HW interrupts around writes to hostrt_data ensures
* that a reader (on the Xenomai side) cannot interrupt a writer (on
* the Linux kernel side) on the same CPU. The sequence counter is
* required when a reader is interleaved by a writer on a different
* CPU. This follows the approach from userland, where tasking the
* spinlock is not possible.
*/
retry:
seq = xnread_seqcount_begin(&hostrt_data->seqcount);
now = xnarch_get_cpu_tsc();
base = hostrt_data->cycle_last;
mask = hostrt_data->mask;
mult = hostrt_data->mult;
shift = hostrt_data->shift;
tp->tv_sec = hostrt_data->wall_time_sec;
nsec = hostrt_data->wall_time_nsec;
if (xnread_seqcount_retry(&hostrt_data->seqcount, seq))
goto retry;
/*
* At this point, we have a consistent copy of the fundamental
* data structure - calculate the interval between the current
* and base time stamp cycles, and convert the difference
* to nanoseconds.
*/
cycle_delta = (now - base) & mask;
nsec += (cycle_delta * mult) >> shift;
/* Convert to the desired sec, usec representation */
tp->tv_sec += xnarch_divrem_billion(nsec, &rem);
tp->tv_nsec = rem;
return 0;
#else /* CONFIG_XENO_OPT_HOSTRT */
return -EINVAL;
#endif
}
