tnt has submitted this change. ( https://gerrit.osmocom.org/c/osmo-e1-hardware/+/27894 )

Change subject: icE1usb fw/gpsdo: Attempt to recover from bad tuning ......................................................................

icE1usb fw/gpsdo: Attempt to recover from bad tuning

If we're in hold over mode and getting a bunch of invalid frequency measurement despite a good fix, then we most likely ended up on a bad tuning value and we need to recover by starting from scratch.

Signed-off-by: Sylvain Munaut tnt@246tNt.com Change-Id: If8503a3eaf695e02a0ef0a3b6536de985d247c20 --- M firmware/ice40-riscv/icE1usb/gpsdo.c 1 file changed, 17 insertions(+), 4 deletions(-)

Approvals: Jenkins Builder: Verified laforge: Looks good to me, approved tnt: Looks good to me, approved

diff --git a/firmware/ice40-riscv/icE1usb/gpsdo.c b/firmware/ice40-riscv/icE1usb/gpsdo.c index c94a5ed..057490f 100644 --- a/firmware/ice40-riscv/icE1usb/gpsdo.c +++ b/firmware/ice40-riscv/icE1usb/gpsdo.c @@ -280,6 +280,7 @@ if (!gps_has_valid_fix()) { /* No GPS fix, go to hold-over */ g_gpsdo.state = STATE_HOLD_OVER; + g_gpsdo.meas.invalid = 0; return; }

@@ -293,10 +294,22 @@ return; } } else { - /* Count invalid measurements and if too many of - * them, we go back to hold-over */ - if (++g_gpsdo.meas.invalid >= MAX_INVALID) - g_gpsdo.state = STATE_HOLD_OVER; + /* Count invalid measurements */ + if (++g_gpsdo.meas.invalid >= MAX_INVALID) { + if (g_gpsdo.state != STATE_HOLD_OVER) { + /* We go back to hold-over */ + g_gpsdo.state = STATE_HOLD_OVER; + g_gpsdo.meas.invalid = 0; + } else { + /* We're in hold-over, with valid fix, and + * still get a bunch of invalid. Reset tuning */ + g_gpsdo.tune.coarse = 2048; + g_gpsdo.tune.fine = 2048; + + pdm_set(PDM_CLK_HI, true, g_gpsdo.tune.coarse, false); + pdm_set(PDM_CLK_LO, true, g_gpsdo.tune.fine, false); + } + }

/* In all cases, invalid measurements are not used */ return;