[Linuxptp-devel] [PATCH 4/6] sysoff: Add support for PTP_SYS_OFFSET_EXTENDED ioctl.

[Miroslav Lichvar]

This is a more accurate variant of the the PTP_SYS_OFFSET ioctl, which
will probably be supported in future kernel versions.

Signed-off-by: Miroslav Lichvar <mlich...@redhat.com>
---
 sysoff.c | 38 ++++++++++++++++++++++++++++++++------
 sysoff.h |  1 +
 2 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/sysoff.c b/sysoff.c
index 9f65d95..b993ee9 100644
--- a/sysoff.c
+++ b/sysoff.c
@@ -71,17 +71,23 @@ static void insertion_sort(int length, int64_t interval, 
int64_t offset, uint64_
        samples[i+1].timestamp = ts;
 }
 
-static int64_t sysoff_estimate(struct ptp_clock_time *pct, int n_samples,
-                              uint64_t *ts, int64_t *delay)
+static int64_t sysoff_estimate(struct ptp_clock_time *pct, int extended,
+                              int n_samples, uint64_t *ts, int64_t *delay)
 {
        int64_t t1, t2, tp;
        int64_t interval, offset;
        int i;
 
        for (i = 0; i < n_samples; i++) {
-               t1 = pctns(&pct[2*i]);
-               tp = pctns(&pct[2*i+1]);
-               t2 = pctns(&pct[2*i+2]);
+               if (extended) {
+                       t1 = pctns(&pct[3*i]);
+                       tp = pctns(&pct[3*i+1]);
+                       t2 = pctns(&pct[3*i+2]);
+               } else {
+                       t1 = pctns(&pct[2*i]);
+                       tp = pctns(&pct[2*i+1]);
+                       t2 = pctns(&pct[2*i+2]);
+               }
                interval = t2 - t1;
                offset = (t2 + t1) / 2 - tp;
                insertion_sort(i, interval, offset, (t2 + t1) / 2);
@@ -91,6 +97,24 @@ static int64_t sysoff_estimate(struct ptp_clock_time *pct, 
int n_samples,
        return samples[0].offset;
 }
 
+static int sysoff_extended(int fd, int n_samples,
+                          int64_t *result, uint64_t *ts, int64_t *delay)
+{
+#ifdef PTP_SYS_OFFSET_EXTENDED
+       struct ptp_sys_offset_extended pso;
+       memset(&pso, 0, sizeof(pso));
+       pso.n_samples = n_samples;
+       if (ioctl(fd, PTP_SYS_OFFSET_EXTENDED, &pso)) {
+               pr_debug("ioctl PTP_SYS_OFFSET_EXTENDED: %m");
+               return SYSOFF_RUN_TIME_MISSING;
+       }
+       *result = sysoff_estimate(&pso.ts[0][0], 1, n_samples, ts, delay);
+       return SYSOFF_EXTENDED;
+#else
+       return SYSOFF_COMPILE_TIME_MISSING;
+#endif
+}
+
 static int sysoff_basic(int fd, int n_samples,
                        int64_t *result, uint64_t *ts, int64_t *delay)
 {
@@ -101,7 +125,7 @@ static int sysoff_basic(int fd, int n_samples,
                perror("ioctl PTP_SYS_OFFSET");
                return SYSOFF_RUN_TIME_MISSING;
        }
-       *result = sysoff_estimate(pso.ts, n_samples, ts, delay);
+       *result = sysoff_estimate(pso.ts, 0, n_samples, ts, delay);
        return SYSOFF_BASIC;
 }
 
@@ -112,6 +136,8 @@ int sysoff_measure(int fd, int method, int n_samples,
        case SYSOFF_PRECISE:
                *delay = 0;
                return sysoff_precise(fd, result, ts);
+       case SYSOFF_EXTENDED:
+               return sysoff_extended(fd, n_samples, result, ts, delay);
        case SYSOFF_BASIC:
                return sysoff_basic(fd, n_samples, result, ts, delay);
        }
diff --git a/sysoff.h b/sysoff.h
index 37f7353..79d2290 100644
--- a/sysoff.h
+++ b/sysoff.h
@@ -24,6 +24,7 @@ enum {
        SYSOFF_COMPILE_TIME_MISSING = -2,
        SYSOFF_RUN_TIME_MISSING = -1,
        SYSOFF_PRECISE,
+       SYSOFF_EXTENDED,
        SYSOFF_BASIC,
        SYSOFF_LAST,
 };
-- 
2.17.2



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