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greybus: tracepoints: Add standard Linux tracepoint for TimeSync event 

This patch adds a tracepoint to the TimeSync ISR, the purpose of which is
to indicate a TimeSync event has happened. This tracepoint can be enabled
by issuing the following command:

echo 1 > /sys/kernel/debug/tracing/events/greybus/gb_timesync_irq/enable

Synchronization looks like this:

 TIMESTAMP  FUNCTION
    |         |
147.865788: gb_timesync_irq: strobe 1/4 frame-time 2910076529
147.866781: gb_timesync_irq: strobe 2/4 frame-time 2910095689
147.867777: gb_timesync_irq: strobe 3/4 frame-time 2910114820
147.868791: gb_timesync_irq: strobe 4/4 frame-time 2910134038

A ping can be triggered like this:

cat /sys/kernel/debug/greybus/frame-time

And that ping looks like this:

 TIMESTAMP  FUNCTION
    |         |
147.934678: gb_timesync_irq: ping 4/4 frame-time 2911380356
169.280551: gb_timesync_irq: ping 4/4 frame-time 3321221069

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Reviewed-by: Vaibhav Hiremath <vaibhav.hiremath@linaro.org>
Acked-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
Bryan O'Donoghue 2016-06-05 14:03:28 +01:00 committed by Greg Kroah-Hartman
parent 4a4484274f
commit 6da7c88972
2 changed files with 40 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
drivers/staging/greybus/greybus_trace.h
View File

@ -488,6 +488,34 @@ DEFINE_HD_EVENT(gb_hd_in);
#undef DEFINE_HD_EVENT
/*
* Occurs on a TimeSync synchronization event or a TimeSync ping event.
*/
TRACE_EVENT(gb_timesync_irq,
TP_PROTO(u8 ping, u8 strobe, u8 count, u64 frame_time),
TP_ARGS(ping, strobe, count, frame_time),
TP_STRUCT__entry(
__field(u8, ping)
__field(u8, strobe)
__field(u8, count)
__field(u64, frame_time)
),
TP_fast_assign(
__entry->ping = ping;
__entry->strobe = strobe;
__entry->count = count;
__entry->frame_time = frame_time;
),
TP_printk("%s %d/%d frame-time %llu\n",
__entry->ping ? "ping" : "strobe", __entry->strobe,
__entry->count, __entry->frame_time)
);
#endif /* _TRACE_GREYBUS_H */
/* This part must be outside protection */

17
drivers/staging/greybus/timesync.c
View File

@ -9,6 +9,7 @@
#include <linux/debugfs.h>
#include "greybus.h"
#include "timesync.h"
#include "greybus_trace.h"
/*
* Minimum inter-strobe value of one millisecond is chosen because it
@ -974,17 +975,19 @@ void gb_timesync_irq(struct gb_timesync_svc *timesync_svc)
{
unsigned long flags;
u64 strobe_time;
bool strobe_is_ping = true;
strobe_time = __gb_timesync_get_frame_time(timesync_svc);
spin_lock_irqsave(&timesync_svc->spinlock, flags);
if (timesync_svc->state == GB_TIMESYNC_STATE_PING) {
if (timesync_svc->capture_ping)
timesync_svc->ap_ping_frame_time = strobe_time;
goto done;
if (!timesync_svc->capture_ping)
goto done_nolog;
timesync_svc->ap_ping_frame_time = strobe_time;
goto done_log;
} else if (timesync_svc->state != GB_TIMESYNC_STATE_WAIT_SVC) {
goto done;
goto done_nolog;
}
timesync_svc->strobe_time[timesync_svc->strobe] = strobe_time;
@ -993,7 +996,11 @@ void gb_timesync_irq(struct gb_timesync_svc *timesync_svc)
gb_timesync_set_state(timesync_svc,
GB_TIMESYNC_STATE_AUTHORITATIVE);
}
done:
strobe_is_ping = false;
done_log:
trace_gb_timesync_irq(strobe_is_ping, timesync_svc->strobe,
GB_TIMESYNC_MAX_STROBES, strobe_time);
done_nolog:
spin_unlock_irqrestore(&timesync_svc->spinlock, flags);
}
EXPORT_SYMBOL(gb_timesync_irq);