Commit 6da7c889 authored by Bryan O'Donoghue's avatar Bryan O'Donoghue Committed by Greg Kroah-Hartman
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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: default avatarBryan O'Donoghue <bryan.odonoghue@linaro.org>
Reviewed-by: default avatarVaibhav Hiremath <vaibhav.hiremath@linaro.org>
Acked-by: default avatarAlex Elder <elder@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@google.com>
parent 4a448427

drivers/staging/greybus/greybus_trace.h

+28 −0
Original line number Diff line number Diff line
@@ -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 */

drivers/staging/greybus/timesync.c

+12 −5
Original line number Diff line number Diff line
@@ -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)

		if (!timesync_svc->capture_ping)

			goto done_nolog;

		timesync_svc->ap_ping_frame_time = strobe_time;

		goto done;

		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);