Detect stuck interrupts in the scc (if DIAGNOSTIC) and log it.

Patches from Bill Studenmund <wrstuden@loki.stanford.edu>.

4 files changed, 52 insertions, 12 deletions

diff --git a/sys/arch/mac68k/dev/z8530sc.c b/sys/arch/mac68k/dev/z8530sc.c
index e686614dd96..7c4ac4b4dbb 100644
--- a/sys/arch/mac68k/dev/z8530sc.c
+++ b/sys/arch/mac68k/dev/z8530sc.c
@@ -1,5 +1,5 @@
-/*	$OpenBSD: z8530sc.c,v 1.2 1996/09/01 18:50:02 briggs Exp $	*/
-/*	$NetBSD: z8530sc.c,v 1.2 1996/08/26 14:09:19 scottr Exp $	*/
+/*	$OpenBSD: z8530sc.c,v 1.3 1996/09/02 15:50:34 briggs Exp $	*/
+/*	$NetBSD: z8530sc.c,v 1.1 1996/05/18 18:54:28 briggs Exp $	*/
 
 /*
  * Copyright (c) 1994 Gordon W. Ross
@@ -297,6 +297,10 @@ zsc_intr_hard(arg)
 	register struct zs_chanstate *cs_b;
 	register int rval;
 	register u_char rr3, rr3a;
+#if DIAGNOSTIC
+	register int loopcount;
+	loopcount = ZS_INTERRUPT_CNT;
+#endif
 
 	cs_a = &zsc->zsc_cs[0];
 	cs_b = &zsc->zsc_cs[1];
@@ -304,27 +308,42 @@ zsc_intr_hard(arg)
 	rr3a = 0;
 
 	/* Note: only channel A has an RR3 */
-	while ((rr3 = zs_read_reg(cs_a, 3))) {
+	rr3 = zs_read_reg(cs_a, 3);
+
+	while ((rr3 = zs_read_reg(cs_a, ZSRR_IPEND))
+#if DIAGNOSTIC
+		 && --loopcount
+#endif
+		) {
+
 		/* Handle receive interrupts first. */
 		if (rr3 & ZSRR3_IP_A_RX)
 			(*cs_a->cs_ops->zsop_rxint)(cs_a);
 		if (rr3 & ZSRR3_IP_B_RX)
 			(*cs_b->cs_ops->zsop_rxint)(cs_b);
-
+	
 		/* Handle status interrupts (i.e. flow control). */
 		if (rr3 & ZSRR3_IP_A_STAT)
 			(*cs_a->cs_ops->zsop_stint)(cs_a);
 		if (rr3 & ZSRR3_IP_B_STAT)
 			(*cs_b->cs_ops->zsop_stint)(cs_b);
-
+	
 		/* Handle transmit done interrupts. */
 		if (rr3 & ZSRR3_IP_A_TX)
 			(*cs_a->cs_ops->zsop_txint)(cs_a);
 		if (rr3 & ZSRR3_IP_B_TX)
 			(*cs_b->cs_ops->zsop_txint)(cs_b);
-
+	
 		rr3a |= rr3;
 	}
+#if DIAGNOSTIC
+	if (loopcount == 0) {
+		if (rr3 & (ZSRR3_IP_A_RX | ZSRR3_IP_A_TX | ZSRR3_IP_A_STAT))
+			cs_a->cs_flags |= ZS_FLAGS_INTERRUPT_OVERRUN;
+		if (rr3 & (ZSRR3_IP_B_RX | ZSRR3_IP_B_TX | ZSRR3_IP_B_STAT))
+			cs_b->cs_flags |= ZS_FLAGS_INTERRUPT_OVERRUN;
+	}
+#endif
 
 	/* Clear interrupt. */
 	if (rr3a & (ZSRR3_IP_A_RX | ZSRR3_IP_A_TX | ZSRR3_IP_A_STAT)) {
diff --git a/sys/arch/mac68k/dev/z8530sc.h b/sys/arch/mac68k/dev/z8530sc.h
index ba19bff490d..4aff44f723b 100644
--- a/sys/arch/mac68k/dev/z8530sc.h
+++ b/sys/arch/mac68k/dev/z8530sc.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: z8530sc.h,v 1.1 1996/05/26 19:02:11 briggs Exp $	*/
+/*	$OpenBSD: z8530sc.h,v 1.2 1996/09/02 15:50:35 briggs Exp $	*/
 /*	$NetBSD: z8530sc.h,v 1.1 1996/05/18 18:54:30 briggs Exp $	*/
 
 /*
@@ -87,10 +87,13 @@ struct zs_chanstate {
 	void *cs_private;	/* sub-driver data pointer */
 	struct zsops *cs_ops;
 
-	int	cs_defspeed;		/* default baud rate (from PROM) */
-	int cs_pclk_div16;		/* PCLK / 16 used only by kbd & ms kids */
 	int	cs_clock_count;		/* how many signal sources available */
 	struct zsclksrc cs_clocks[4];	/* info on available signal sources */
+	int	cs_defspeed;		/* default baud rate (from PROM) */
+	int cs_pclk_div16;		/* PCLK / 16 used by zs children w/o multiple
+					 * baud support - some ports have only
+					 * one clock source, and some children (kbd & ms)
+					 * are fixed baud rate */
 
 	/*
 	 * We must keep a copy of the write registers as they are
@@ -118,8 +121,19 @@ struct zs_chanstate {
 
 	char	cs_softreq;		/* need soft interrupt call */
 	char	cs_chip;		/* type of chip */
-	char	cs__spare; 
+	char	cs_flags;		/* misc. flags */
 };
+#define ZS_INTERRUPT_CNT		10
+#define ZS_FLAGS_INTERRUPT_OVERRUN	0x01
+#define ZS_FLAGS_DEBUG1			0x10
+	/* The interrupt service routine will now look to see if more interrupts
+	 * come in while servicing an interrupt. If so, it keeps servicing
+	 * them either to exhaustion or until it's tried ZS_INTERRUPT_CNT times.
+	 * If it tries too many times, it flags a ZS_FLAGS_INTERRUPT_OVERRUN.
+	 * It shouldn't, but w/o a counter of sorts, we could get hung in an
+	 * infinite loop because of sick hardware, or because there's a data
+	 * clock fed on one of the inputs. The DEBUG flag is for testing and has
+	 * no permanant definition. */
 #define	ZS_ENHANCED_REG	8
 	/* cs_Xreg which is used to hold WR7' data; reg 8 is an alias to the
 	 * data port, so we won't miss its loss. */
diff --git a/sys/arch/mac68k/dev/z8530tty.c b/sys/arch/mac68k/dev/z8530tty.c
index 1a2d7876152..2ebf29f0465 100644
--- a/sys/arch/mac68k/dev/z8530tty.c
+++ b/sys/arch/mac68k/dev/z8530tty.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: z8530tty.c,v 1.2 1996/06/08 16:21:13 briggs Exp $	*/
+/*	$OpenBSD: z8530tty.c,v 1.3 1996/09/02 15:50:35 briggs Exp $	*/
 /*	$NetBSD: z8530tty.c,v 1.3 1996/06/01 00:13:41 scottr Exp $	*/
 
 /*
@@ -1321,6 +1321,12 @@ zstty_softint(cs)
 		zst->zst_rx_overrun = 0;
 		zsoverrun(zst, &zst->zst_rotime, "ring");
 	}
+	if (cs->cs_flags & ZS_FLAGS_INTERRUPT_OVERRUN) {
+		(void) splzs();
+		cs->cs_flags &= ~ZS_FLAGS_INTERRUPT_OVERRUN;
+		(void) spltty();
+		zsoverrun(zst, &zst->zst_intotime, "interrupt");
+	}
 
 	/*
 	 * Copy data from the receive ring into the tty layer.
diff --git a/sys/arch/mac68k/dev/z8530tty.h b/sys/arch/mac68k/dev/z8530tty.h
index b292b474edb..f79ce22466f 100644
--- a/sys/arch/mac68k/dev/z8530tty.h
+++ b/sys/arch/mac68k/dev/z8530tty.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: z8530tty.h,v 1.1 1996/05/26 19:02:13 briggs Exp $	*/
+/*	$OpenBSD: z8530tty.h,v 1.2 1996/09/02 15:50:36 briggs Exp $	*/
 /*	$NetBSD: z8530tty.h,v 1.1 1996/05/18 18:54:35 briggs Exp $	*/
 
 /*
@@ -92,6 +92,7 @@ struct zstty_softc {
 	 */
 	long	zst_rotime;		/* time of last ring overrun */
 	long	zst_fotime;		/* time of last fifo overrun */
+	long	zst_intotime;		/* time of last interrupt overrun */
 
 	/*
 	 * The receive ring buffer.