firewire: ohci: add tracepoints event for hardIRQ event

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>

diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
index 07adb4ddd4448774c02986d86c5748f1addbea34..df16a8f4ee7f80b75f1df7e5cdf0f40561350662 100644 (file)
--- 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 67fa3c1c8f6d98ba48f5265e9aba9b8794feabf6..483aeeb033afd8a39f3f93ee19652c378c77a15f 100644 (file)
--- 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