platform/chrome: sensorhub: Add trace events for sample

Add trace event to report samples and their timestamp coming from the
EC. It allows to check if the timestamps are correct and the filter is
working correctly without introducing too much latency.

To enable these events:

cd /sys/kernel/debug/tracing/
echo 1 > events/cros_ec/enable
echo 0 > events/cros_ec/cros_ec_request_start/enable
echo 0 > events/cros_ec/cros_ec_request_done/enable
echo 1 > tracing_on
cat trace_pipe
Observe event flowing:
irq/105-chromeo-95      [000] ....   613.659758: cros_ec_sensorhub_timestamp: ...
irq/105-chromeo-95      [000] ....   613.665219: cros_ec_sensorhub_filter: dx: ...

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

drivers/platform/chrome/Makefile

@@ -20,7 +20,7 @@ obj-$(CONFIG_CROS_EC_CHARDEV)		+= cros_ec_chardev.o
 obj-$(CONFIG_CROS_EC_LIGHTBAR)		+= cros_ec_lightbar.o
 obj-$(CONFIG_CROS_EC_VBC)		+= cros_ec_vbc.o
 obj-$(CONFIG_CROS_EC_DEBUGFS)		+= cros_ec_debugfs.o
-cros-ec-sensorhub-objs			:= cros_ec_sensorhub.o cros_ec_sensorhub_ring.o
+cros-ec-sensorhub-objs			:= cros_ec_sensorhub.o cros_ec_sensorhub_ring.o cros_ec_trace.o
 obj-$(CONFIG_CROS_EC_SENSORHUB)		+= cros-ec-sensorhub.o
 obj-$(CONFIG_CROS_EC_SYSFS)		+= cros_ec_sysfs.o
 obj-$(CONFIG_CROS_USBPD_LOGGER)		+= cros_usbpd_logger.o

drivers/platform/chrome/cros_ec_sensorhub_ring.c

@@ -17,6 +17,8 @@
 #include <linux/sort.h>
 #include <linux/slab.h>
 
+#include "cros_ec_trace.h"
+
 /* Precision of fixed point for the m values from the filter */
 #define M_PRECISION BIT(23)
 
@@ -291,6 +293,7 @@ cros_ec_sensor_ring_ts_filter_update(struct cros_ec_sensors_ts_filter_state
 		state->median_m = 0;
 		state->median_error = 0;
 	}
+	trace_cros_ec_sensorhub_filter(state, dx, dy);
 }
 
 /**
@@ -427,6 +430,11 @@ cros_ec_sensor_ring_process_event(struct cros_ec_sensorhub *sensorhub,
 			if (new_timestamp - *current_timestamp > 0)
 				*current_timestamp = new_timestamp;
 		}
+		trace_cros_ec_sensorhub_timestamp(in->timestamp,
+						  fifo_info->timestamp,
+						  fifo_timestamp,
+						  *current_timestamp,
+						  now);
 	}
 
 	if (in->flags & MOTIONSENSE_SENSOR_FLAG_ODR) {
@@ -460,6 +468,12 @@ cros_ec_sensor_ring_process_event(struct cros_ec_sensorhub *sensorhub,
 
 	/* Regular sample */
 	out->sensor_id = in->sensor_num;
+	trace_cros_ec_sensorhub_data(in->sensor_num,
+				     fifo_info->timestamp,
+				     fifo_timestamp,
+				     *current_timestamp,
+				     now);
+
 	if (*current_timestamp - now > 0) {
 		/*
 		 * This fix is needed to overcome the timestamp filter putting

drivers/platform/chrome/cros_ec_trace.h

@@ -15,6 +15,7 @@
 #include <linux/types.h>
 #include <linux/platform_data/cros_ec_commands.h>
 #include <linux/platform_data/cros_ec_proto.h>
+#include <linux/platform_data/cros_ec_sensorhub.h>
 
 #include <linux/tracepoint.h>
 
@@ -70,6 +71,99 @@ TRACE_EVENT(cros_ec_request_done,
 		  __entry->retval)
 );
 
+TRACE_EVENT(cros_ec_sensorhub_timestamp,
+	    TP_PROTO(u32 ec_sample_timestamp, u32 ec_fifo_timestamp, s64 fifo_timestamp,
+		     s64 current_timestamp, s64 current_time),
+	TP_ARGS(ec_sample_timestamp, ec_fifo_timestamp, fifo_timestamp, current_timestamp,
+		current_time),
+	TP_STRUCT__entry(
+		__field(u32, ec_sample_timestamp)
+		__field(u32, ec_fifo_timestamp)
+		__field(s64, fifo_timestamp)
+		__field(s64, current_timestamp)
+		__field(s64, current_time)
+		__field(s64, delta)
+	),
+	TP_fast_assign(
+		__entry->ec_sample_timestamp = ec_sample_timestamp;
+		__entry->ec_fifo_timestamp = ec_fifo_timestamp;
+		__entry->fifo_timestamp = fifo_timestamp;
+		__entry->current_timestamp = current_timestamp;
+		__entry->current_time = current_time;
+		__entry->delta = current_timestamp - current_time;
+	),
+	TP_printk("ec_ts: %12lld, ec_fifo_ts: %12lld, fifo_ts: %12lld, curr_ts: %12lld, curr_time: %12lld, delta %12lld",
+		  __entry->ec_sample_timestamp,
+		__entry->ec_fifo_timestamp,
+		__entry->fifo_timestamp,
+		__entry->current_timestamp,
+		__entry->current_time,
+		__entry->delta
+	)
+);
+
+TRACE_EVENT(cros_ec_sensorhub_data,
+	    TP_PROTO(u32 ec_sensor_num, u32 ec_fifo_timestamp, s64 fifo_timestamp,
+		     s64 current_timestamp, s64 current_time),
+	TP_ARGS(ec_sensor_num, ec_fifo_timestamp, fifo_timestamp, current_timestamp, current_time),
+	TP_STRUCT__entry(
+		__field(u32, ec_sensor_num)
+		__field(u32, ec_fifo_timestamp)
+		__field(s64, fifo_timestamp)
+		__field(s64, current_timestamp)
+		__field(s64, current_time)
+		__field(s64, delta)
+	),
+	TP_fast_assign(
+		__entry->ec_sensor_num = ec_sensor_num;
+		__entry->ec_fifo_timestamp = ec_fifo_timestamp;
+		__entry->fifo_timestamp = fifo_timestamp;
+		__entry->current_timestamp = current_timestamp;
+		__entry->current_time = current_time;
+		__entry->delta = current_timestamp - current_time;
+	),
+	TP_printk("ec_num: %4d, ec_fifo_ts: %12lld, fifo_ts: %12lld, curr_ts: %12lld, curr_time: %12lld, delta %12lld",
+		  __entry->ec_sensor_num,
+		__entry->ec_fifo_timestamp,
+		__entry->fifo_timestamp,
+		__entry->current_timestamp,
+		__entry->current_time,
+		__entry->delta
+	)
+);
+
+TRACE_EVENT(cros_ec_sensorhub_filter,
+	    TP_PROTO(struct cros_ec_sensors_ts_filter_state *state, s64 dx, s64 dy),
+	TP_ARGS(state, dx, dy),
+	TP_STRUCT__entry(
+		__field(s64, dx)
+		__field(s64, dy)
+		__field(s64, median_m)
+		__field(s64, median_error)
+		__field(s64, history_len)
+		__field(s64, x)
+		__field(s64, y)
+	),
+	TP_fast_assign(
+		__entry->dx = dx;
+		__entry->dy = dy;
+		__entry->median_m = state->median_m;
+		__entry->median_error = state->median_error;
+		__entry->history_len = state->history_len;
+		__entry->x = state->x_offset;
+		__entry->y = state->y_offset;
+	),
+	TP_printk("dx: %12lld. dy: %12lld median_m: %12lld median_error: %12lld len: %d x: %12lld y: %12lld",
+		  __entry->dx,
+		__entry->dy,
+		__entry->median_m,
+		__entry->median_error,
+		__entry->history_len,
+		__entry->x,
+		__entry->y
+	)
+);
+
 
 #endif /* _CROS_EC_TRACE_H_ */