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platform/chrome: cros_ec_sensorhub: Add code to spread timestmap 

EC FIFO can send sensor events in batch. Spread them based on
previous (TSa) and currnet timestamp (TSb)

  EC FIFO                             iio events
+-----------+
| TSa       |
+-----------+             +---------------------------------------+
| event 1   |             | event 1 | TSb - (TSb - TSa)/n * (n-1) |
+-----------+             +---------------------------------------+
| event 2   |             | event 2 | TSb - (TSb - TSa)/n * (n-2) |
+-----------+             +---------------------------------------+
|  ...      |  ------>    |  ....   |                             |
+-----------+             +---------------------------------------+
| event n-1 |             | event 2 | TSb - (TSb - TSa)/n         |
+-----------+             +---------------------------------------+
| event n   |             | event 2 | TSb                         |
+-----------+             +---------------------------------------+
| TSb       |
+-----------+

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
This commit is contained in:
Gwendal Grignou 2020-03-27 15:34:34 -07:00 committed by Enric Balletbo i Serra
parent 145d59baff
commit b9b05664eb
1 changed files with 109 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

117
drivers/platform/chrome/cros_ec_sensorhub_ring.c
View File

@ -190,6 +190,101 @@ cros_ec_sensor_ring_process_event(struct cros_ec_sensorhub *sensorhub,
return true;
}
/*
* cros_ec_sensor_ring_spread_add: Calculate proper timestamps then add to
* ringbuffer.
*
* If there is a sample with a proper timestamp
*
* timestamp | count
* -----------------
* older_unprocess_out --> TS1 | 1
* TS1 | 2
* out --> TS1 | 3
* next_out --> TS2 |
*
* We spread time for the samples [older_unprocess_out .. out]
* between TS1 and TS2: [TS1+1/4, TS1+2/4, TS1+3/4, TS2].
*
* If we reach the end of the samples, we compare with the
* current timestamp:
*
* older_unprocess_out --> TS1 | 1
* TS1 | 2
* out --> TS1 | 3
*
* We know have [TS1+1/3, TS1+2/3, current timestamp]
*/
static void cros_ec_sensor_ring_spread_add(struct cros_ec_sensorhub *sensorhub,
unsigned long sensor_mask,
s64 current_timestamp,
struct cros_ec_sensors_ring_sample
*last_out)
{
struct cros_ec_sensors_ring_sample *out;
int i;
for_each_set_bit(i, &sensor_mask, sensorhub->sensor_num) {
s64 older_timestamp;
s64 timestamp;
struct cros_ec_sensors_ring_sample *older_unprocess_out =
sensorhub->ring;
struct cros_ec_sensors_ring_sample *next_out;
int count = 1;
for (out = sensorhub->ring; out < last_out; out = next_out) {
s64 time_period;
next_out = out + 1;
if (out->sensor_id != i)
continue;
/* Timestamp to start with */
older_timestamp = out->timestamp;
/* Find next sample. */
while (next_out < last_out && next_out->sensor_id != i)
next_out++;
if (next_out >= last_out) {
timestamp = current_timestamp;
} else {
timestamp = next_out->timestamp;
if (timestamp == older_timestamp) {
count++;
continue;
}
}
/*
* The next sample has a new timestamp, spread the
* unprocessed samples.
*/
if (next_out < last_out)
count++;
time_period = div_s64(timestamp - older_timestamp,
count);
for (; older_unprocess_out <= out;
older_unprocess_out++) {
if (older_unprocess_out->sensor_id != i)
continue;
older_timestamp += time_period;
older_unprocess_out->timestamp =
older_timestamp;
}
count = 1;
/* The next_out sample has a valid timestamp, skip. */
next_out++;
older_unprocess_out = next_out;
}
}
/* Push the event into the kfifo */
for (out = sensorhub->ring; out < last_out; out++)
cros_sensorhub_send_sample(sensorhub, out);
}
/**
* cros_ec_sensorhub_ring_handler() - The trigger handler function
*
@ -204,6 +299,7 @@ static void cros_ec_sensorhub_ring_handler(struct cros_ec_sensorhub *sensorhub)
struct cros_ec_dev *ec = sensorhub->ec;
ktime_t fifo_timestamp, current_timestamp;
int i, j, number_data, ret;
unsigned long sensor_mask = 0;
struct ec_response_motion_sensor_data *in;
struct cros_ec_sensors_ring_sample *out, *last_out;
@ -289,10 +385,12 @@ static void cros_ec_sensorhub_ring_handler(struct cros_ec_sensorhub *sensorhub)
sensorhub, fifo_info,
fifo_timestamp,
&current_timestamp,
in, out))
in, out)) {
sensor_mask |= BIT(in->sensor_num);
out++;
}
}
}
mutex_unlock(&sensorhub->cmd_lock);
last_out = out;
@ -301,10 +399,10 @@ static void cros_ec_sensorhub_ring_handler(struct cros_ec_sensorhub *sensorhub)
goto ring_handler_end;
/*
* Check if current_timestamp is ahead of the last sample.
* Normally, the EC appends a timestamp after the last sample, but if
* the AP is slow to respond to the IRQ, the EC may have added new
* samples. Use the FIFO info timestamp as last timestamp then.
* Check if current_timestamp is ahead of the last sample. Normally,
* the EC appends a timestamp after the last sample, but if the AP
* is slow to respond to the IRQ, the EC may have added new samples.
* Use the FIFO info timestamp as last timestamp then.
*/
if ((last_out - 1)->timestamp == current_timestamp)
current_timestamp = fifo_timestamp;
@ -319,9 +417,12 @@ static void cros_ec_sensorhub_ring_handler(struct cros_ec_sensorhub *sensorhub)
fifo_info->total_lost);
}
/* Push the event into the FIFO. */
for (out = sensorhub->ring; out < last_out; out++)
cros_sensorhub_send_sample(sensorhub, out);
/*
* Spread samples in case of batching, then add them to the
* ringbuffer.
*/
cros_ec_sensor_ring_spread_add(sensorhub, sensor_mask,
current_timestamp, last_out);
ring_handler_end:
sensorhub->fifo_timestamp[CROS_EC_SENSOR_LAST_TS] = current_timestamp;