[PATCH linux-evl] evl/latmus: fix spurious overrun on first measurement sample

This delta is not fixed up during the warmup phase leading to spourious
overruns in the first measurement sample.

Also apply the fixup in the warmup phase.

Signed-off-by: Tobias Schaffner <[email protected]>
---
 drivers/evl/latmus.c | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/evl/latmus.c b/drivers/evl/latmus.c
index 9a0295044443..9c581d80db68 100644
--- a/drivers/evl/latmus.c
+++ b/drivers/evl/latmus.c
@@ -166,14 +166,23 @@ static int add_measurement_sample(struct latmus_runner *runner,
 	ktime_t period = runner->period;
 	int delta, cell, offset_delta;
 
+	delta = (int)ktime_to_ns(ktime_sub(timestamp, state->ideal));
+	state->ideal = ktime_add(state->ideal, period);
+
+	while (delta > 0 &&
+		(unsigned int)delta > ktime_to_ns(period)) { /* period > 0 */
+		if (runner->warmup_samples >= runner->warmup_limit)
+			state->overruns++;
+		state->ideal = ktime_add(state->ideal, period);
+		delta -= ktime_to_ns(period);
+	}
+
 	/* Skip samples in warmup time. */
 	if (runner->warmup_samples < runner->warmup_limit) {
 		runner->warmup_samples++;
-		state->ideal = ktime_add(state->ideal, period);
 		return 0;
 	}
 
-	delta = (int)ktime_to_ns(ktime_sub(timestamp, state->ideal));
 	offset_delta = delta - state->offset;
 	if (offset_delta < state->min_lat)
 		state->min_lat = offset_delta;
@@ -193,14 +202,6 @@ static int add_measurement_sample(struct latmus_runner *runner,
 	}
 
 	state->sum += offset_delta;
-	state->ideal = ktime_add(state->ideal, period);
-
-	while (delta > 0 &&
-		(unsigned int)delta > ktime_to_ns(period)) { /* period > 0 */
-		state->overruns++;
-		state->ideal = ktime_add(state->ideal, period);
-		delta -= ktime_to_ns(period);
-	}
 
 	if (++state->cur_samples >= state->max_samples)
 		send_measurement(runner);
-- 
2.43.0