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firewire: ohci: add tracepoints event for hardIRQ event

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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.

Link: https://lore.kernel.org/r/20240625031806.956650-3-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
This commit is contained in:
Takashi Sakamoto 2024-06-25 12:18:06 +09:00
parent 001c1ff5dc
commit 0d8914165d
2 changed files with 33 additions and 1 deletions
drivers/firewire
ohci.c
include/trace/events
firewire_ohci.h

1
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)

33
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