[PATCH 2/2] firewire: ohci: add tracepoints event for hardIRQ event

[Takashi Sakamoto]

1394 OHCI hardware triggers PCI interrupts to notify any events to
software. Current driver for the hardware is programmed by the typical
way to utilize top- and bottom- halves, thus it has a timing gap to handle
the notification in softIRQ (tasklet).

This commit adds a tracepoint event for the hardIRQ event. The comparison
of the tracepoint event to tracepoints events in firewire subsystem is
helpful to diagnose the timing gap.

Signed-off-by: Takashi Sakamoto <o-takashi@xxxxxxxxxxxxx>
---
 drivers/firewire/ohci.c              |  1 +
 include/trace/events/firewire_ohci.h | 33 +++++++++++++++++++++++++++-
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
index 07adb4ddd444..df16a8f4ee7f 100644
--- a/drivers/firewire/ohci.c
+++ b/drivers/firewire/ohci.c
@@ -2185,6 +2185,7 @@ static irqreturn_t irq_handler(int irq, void *data)
 	 */
 	reg_write(ohci, OHCI1394_IntEventClear,
 		  event & ~(OHCI1394_busReset | OHCI1394_postedWriteErr));
+	trace_irqs(ohci->card.index, event);
 	log_irqs(ohci, event);
 	// The flag is masked again at bus_reset_work() scheduled by selfID event.
 	if (event & OHCI1394_busReset)
diff --git a/include/trace/events/firewire_ohci.h b/include/trace/events/firewire_ohci.h
index 67fa3c1c8f6d..483aeeb033af 100644
--- a/include/trace/events/firewire_ohci.h
+++ b/include/trace/events/firewire_ohci.h
@@ -9,7 +9,38 @@
 
 #include <linux/tracepoint.h>
 
-// Placeholder for future use.
+TRACE_EVENT(irqs,
+	TP_PROTO(unsigned int card_index, u32 events),
+	TP_ARGS(card_index, events),
+	TP_STRUCT__entry(
+		__field(u8, card_index)
+		__field(u32, events)
+	),
+	TP_fast_assign(
+		__entry->card_index = card_index;
+		__entry->events = events;
+	),
+	TP_printk(
+		"card_index=%u events=%s",
+		__entry->card_index,
+		__print_flags(__entry->events, "|",
+			{ OHCI1394_selfIDComplete,	"selfIDComplete" },
+			{ OHCI1394_RQPkt,		"RQPkt" },
+			{ OHCI1394_RSPkt,		"RSPkt" },
+			{ OHCI1394_reqTxComplete,	"reqTxComplete" },
+			{ OHCI1394_respTxComplete,	"respTxComplete" },
+			{ OHCI1394_isochRx,		"isochRx" },
+			{ OHCI1394_isochTx,		"isochTx" },
+			{ OHCI1394_postedWriteErr,	"postedWriteErr" },
+			{ OHCI1394_cycleTooLong,	"cycleTooLong" },
+			{ OHCI1394_cycle64Seconds,	"cycle64Seconds" },
+			{ OHCI1394_cycleInconsistent,	"cycleInconsistent" },
+			{ OHCI1394_regAccessFail,	"regAccessFail" },
+			{ OHCI1394_unrecoverableError,	"unrecoverableError" },
+			{ OHCI1394_busReset,		"busReset" }
+		)
+	)
+);
 
 #endif // _FIREWIRE_OHCI_TRACE_EVENT_H
 
-- 
2.43.0