diff options
| author | Alexandru M Stan <amstan@chromium.org> | 2017-11-30 20:43:15 -0800 |
|---|---|---|
| committer | chrome-bot <chrome-bot@chromium.org> | 2018-05-14 15:32:47 -0700 |
| commit | 1d518fb85cd7163a2fc390871046d8d6c398ed57 (patch) | |
| tree | 47da7c7ac36b3f7a1e150ed0a7912eed302f624b /include | |
| parent | fda59e57ff0b1ad29786d35abb5ba189011fb479 (diff) | |
| download | chrome-ec-1d518fb85cd7163a2fc390871046d8d6c398ed57.tar.gz | |
motion_sense: Lower jitter of EC->AP timestamp
When the EC sends an interrupt to the AP notifying it of new
accelerometer data we need to make sure the spot we record the timestamp
of the event is virtually identical to the spot the AP records the same
point in time.
Therefore a better spot for that is right next to the gpio toggling of
the interrupt line.
BUG=b:67743747
TEST=In the kernel, fifo_info->info.timestamp still has sane values.
TEST=CTS should still pass
BRANCH=master
Change-Id: Ic77101a045123e779f576c46b401c765304976fd
Signed-off-by: Alexandru M Stan <amstan@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/802976
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/ec_commands.h | 4 | ||||
| -rw-r--r-- | include/mkbp_event.h | 9 |
2 files changed, 12 insertions, 1 deletions
diff --git a/include/ec_commands.h b/include/ec_commands.h index cf7148e535..efbb23f785 100644 --- a/include/ec_commands.h +++ b/include/ec_commands.h @@ -2323,7 +2323,9 @@ struct __ec_todo_packed ec_response_motion_sense_fifo_info { uint16_t size; /* Amount of space used in the fifo */ uint16_t count; - /* Timestamp recorded in us */ + /* Timestamp recorded in us. + * aka accurate timestamp when host event was triggered. + */ uint32_t timestamp; /* Total amount of vector lost */ uint16_t total_lost; diff --git a/include/mkbp_event.h b/include/mkbp_event.h index cad43444b5..68e29c0cd4 100644 --- a/include/mkbp_event.h +++ b/include/mkbp_event.h @@ -9,6 +9,15 @@ #define __CROS_EC_MKBP_EVENT_H /* + * Last time the host received an interrupt. + * + * Retrieved via __hw_clock_source_read() as close as possible + * to the interrupt source. Intended to be virtually the same time the + * first line of the AP hard irq for the EC interrupt. + */ +extern uint32_t mkbp_last_event_time; + +/* * Sends an event to the AP. * * When this is called, the event data must be ready for query. Otherwise, |