esp_dreq_debug.patch

diff --git a/obio/esp.c b/obio/esp.c
index 6580436..fc71876 100644
--- a/obio/esp.c
+++ b/obio/esp.c
@@ -103,6 +103,18 @@ __KERNEL_RCSID(0, "$NetBSD: esp.c,v 1.60 2021/02/22 05:23:36 rin Exp $");
 #include <mac68k/obio/espvar.h>
 #include <mac68k/obio/obiovar.h>
 
+#ifdef ESP_DREQ_DEBUG
+#include <sys/evcnt.h>
+#define	ESP_EVCNT_ATTACH(name)						\
+    static struct evcnt esp_ev_##name =					\
+    EVCNT_INITIALIZER(EVCNT_TYPE_TRAP, NULL, "esp", #name);		\
+    EVCNT_ATTACH_STATIC(esp_ev_##name)
+#define	ESP_EVCNT_INCR(name)	esp_ev_##name.ev_count++
+ESP_EVCNT_ATTACH(dreq0);
+ESP_EVCNT_ATTACH(dreq1);
+ESP_EVCNT_ATTACH(spurious);
+#endif
+
 static int	espmatch(device_t, cfdata_t, void *);
 static void	espattach(device_t, device_t, void *);
 
@@ -693,8 +705,18 @@ esp_dafb_have_dreq(struct esp_softc *esc)
 static int
 esp_iosb_have_dreq(struct esp_softc *esc)
 {
+#ifdef ESP_DREQ_DEBUG
+	int val = via2_reg(vIFR) & V2IF_SCSIDRQ;
+
+	if (val)
+		ESP_EVCNT_INCR(dreq1);
+	else
+		ESP_EVCNT_INCR(dreq0);
+	return val;
+#else
 
 	return via2_reg(vIFR) & V2IF_SCSIDRQ;
+#endif
 }
 
 static volatile int espspl = -1;
@@ -978,6 +1000,11 @@ esp_intr(void *sc)
 	if (esc->sc_reg[NCR_STAT * 16] & 0x80) {
 		ncr53c9x_intr((struct ncr53c9x_softc *)esp0);
 	}
+#ifdef ESP_DREQ_DEBUG
+	else {
+		ESP_EVCNT_INCR(spurious);
+	}
+#endif
 }
 
 static void