diff options
| author | Laurence Evans <levans@solarflare.com> | 2013-11-21 10:38:24 +0000 |
|---|---|---|
| committer | Ben Hutchings <bhutchings@solarflare.com> | 2013-12-12 22:07:08 +0000 |
| commit | dfd8d581fbdce9f3b4777a7c59d28ca35ed194be (patch) | |
| tree | e48f0e1fb90d2b0d57ecb99508b985ae2a3a4727 /drivers/net/ethernet/sfc/ptp.c | |
| parent | 94cd60d09eba9e8de0522d416d867fb16858fccd (diff) | |
sfc: Tidy up PTP synchronization code
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Diffstat (limited to 'drivers/net/ethernet/sfc/ptp.c')
| -rw-r--r-- | drivers/net/ethernet/sfc/ptp.c | 44 |
1 files changed, 24 insertions, 20 deletions
diff --git a/drivers/net/ethernet/sfc/ptp.c b/drivers/net/ethernet/sfc/ptp.c index 82d8e27e8a58..361d7cedd897 100644 --- a/drivers/net/ethernet/sfc/ptp.c +++ b/drivers/net/ethernet/sfc/ptp.c @@ -435,7 +435,6 @@ efx_ptp_process_times(struct efx_nic *efx, MCDI_DECLARE_STRUCT_PTR(synch_buf), MCDI_VAR_ARRAY_LEN(response_length, PTP_OUT_SYNCHRONIZE_TIMESET); unsigned i; - unsigned total; unsigned ngood = 0; unsigned last_good = 0; struct efx_ptp_data *ptp = efx->ptp_data; @@ -446,33 +445,38 @@ efx_ptp_process_times(struct efx_nic *efx, MCDI_DECLARE_STRUCT_PTR(synch_buf), if (number_readings == 0) return -EAGAIN; - /* Read the set of results and increment stats for any results that - * appera to be erroneous. + /* Read the set of results and find the last good host-MC + * synchronization result. The MC times when it finishes reading the + * host time so the corrected window time should be fairly constant + * for a given platform. */ for (i = 0; i < number_readings; i++) { + s32 window, corrected; + efx_ptp_read_timeset( MCDI_ARRAY_STRUCT_PTR(synch_buf, PTP_OUT_SYNCHRONIZE_TIMESET, i), &ptp->timeset[i]); - } - /* Find the last good host-MC synchronization result. The MC times - * when it finishes reading the host time so the corrected window time - * should be fairly constant for a given platform. - */ - total = 0; - for (i = 0; i < number_readings; i++) - if (ptp->timeset[i].window > ptp->timeset[i].waitns) { - unsigned win; - - win = ptp->timeset[i].window - ptp->timeset[i].waitns; - if (win >= MIN_SYNCHRONISATION_NS && - win < MAX_SYNCHRONISATION_NS) { - total += ptp->timeset[i].window; - ngood++; - last_good = i; - } + window = ptp->timeset[i].window; + corrected = window - ptp->timeset[i].waitns; + + /* We expect the uncorrected synchronization window to be at + * least as large as the interval between host start and end + * times. If it is smaller than this then this is mostly likely + * to be a consequence of the host's time being adjusted. + * Check that the corrected sync window is in a reasonable + * range. If it is out of range it is likely to be because an + * interrupt or other delay occurred between reading the system + * time and writing it to MC memory. + */ + if (window >= SYNCHRONISATION_GRANULARITY_NS && + corrected < MAX_SYNCHRONISATION_NS && + corrected >= MIN_SYNCHRONISATION_NS) { + ngood++; + last_good = i; } + } if (ngood == 0) { netif_warn(efx, drv, efx->net_dev, |