Use a simpler delay() routine for MVME188, from Mach via Luna88k

3 files changed, 39 insertions, 17 deletions

diff --git a/sys/arch/mvme88k/dev/clock.c b/sys/arch/mvme88k/dev/clock.c
index b964137b67c..98a4bd98dbb 100644
--- a/sys/arch/mvme88k/dev/clock.c
+++ b/sys/arch/mvme88k/dev/clock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: clock.c,v 1.38 2004/08/24 22:01:29 miod Exp $ */
+/*	$OpenBSD: clock.c,v 1.39 2004/08/25 08:00:06 miod Exp $ */
 /*
  * Copyright (c) 1999 Steve Murphree, Jr.
  * Copyright (c) 1995 Theo de Raadt
@@ -580,15 +580,9 @@ void
 delay(int us)
 {
 	if (brdtyp == BRD_188) {
-		extern int cpuspeed;
+		extern void m188_delay(int);
 
-		/*
-		 * Unable to use a real timer, use a tight loop.
-		 * XXX not accurate!
-		 */
-		volatile int c = (3 * us) / (cpuspeed == 25 ? 4 : 5);
-		while (--c > 0)
-			;
+		m188_delay(us);
 	} else {
 		/*
 		 * On MVME187 and MVME197, use the VMEchip for the
diff --git a/sys/arch/mvme88k/mvme88k/locore.S b/sys/arch/mvme88k/mvme88k/locore.S
index 3c5a05886f9..62c3b7468a5 100644
--- a/sys/arch/mvme88k/mvme88k/locore.S
+++ b/sys/arch/mvme88k/mvme88k/locore.S
@@ -1,4 +1,4 @@
-/*	$OpenBSD: locore.S,v 1.37 2004/08/09 20:52:11 miod Exp $	*/
+/*	$OpenBSD: locore.S,v 1.38 2004/08/25 08:00:08 miod Exp $	*/
 /*
  * Copyright (c) 1998 Steve Murphree, Jr.
  * Copyright (c) 1996 Nivas Madhur
@@ -406,6 +406,34 @@ GLOBAL(spin_cpu)
 	tb0	0,    r0,  0x200-16		/* call 188Bug */
 	jmp	r1
 
+#ifdef MVME188
+/* 
+ * void m188_delay(int us)
+ *
+ * The processor loops (busy waits) for the given number of microseconds:
+ * Thus, delay(1000000) will delay for one second.
+ * (originally from Mach 2.5) 
+ * 
+ * REGISTER USAGE:
+ *  IN	r1   - return address
+ *  IN	r2   - number of microseconds
+ *	r3   - cpu speed in MHz
+ *	r4   - number of cycles to delay
+ */
+GLOBAL(m188_delay)
+	or.u	r3, r0, hi16(_cpuspeed)
+	ld	r3, r3, lo16(_cpuspeed)
+	mul	r4, r2, r3
+	subu	r4, r4, 4	/* overhead of these instructions */
+
+	/* now loop for the given number of cycles */
+1: 
+	bcnd.n	gt0, r4, 1b
+	 subu	r4, r4, 2	/* two cycles per iteration */
+
+	jmp	r1
+#endif
+
 /*****************************************************************************/
 
 	data
diff --git a/sys/arch/mvme88k/mvme88k/machdep.c b/sys/arch/mvme88k/mvme88k/machdep.c
index 4f92e02a7f7..a66011171c8 100644
--- a/sys/arch/mvme88k/mvme88k/machdep.c
+++ b/sys/arch/mvme88k/mvme88k/machdep.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: machdep.c,v 1.154 2004/08/02 14:38:42 miod Exp $	*/
+/* $OpenBSD: machdep.c,v 1.155 2004/08/25 08:00:09 miod Exp $	*/
 /*
  * Copyright (c) 1998, 1999, 2000, 2001 Steve Murphree, Jr.
  * Copyright (c) 1996 Nivas Madhur
@@ -233,12 +233,12 @@ char  cpu_model[120];
 extern char *esym;
 #endif
 
-int boothowto;	/* set in locore.S */
-int bootdev;	/* set in locore.S */
-int cputyp;	/* set in locore.S */
-int brdtyp;	/* set in locore.S */
-int cpumod;	/* set in mvme_bootstrap() */
-int cpuspeed;
+int boothowto;					/* set in locore.S */
+int bootdev;					/* set in locore.S */
+int cputyp;					/* set in locore.S */
+int brdtyp;					/* set in locore.S */
+int cpumod;					/* set in mvme_bootstrap() */
+int cpuspeed = 25;				/* safe guess */
 
 vaddr_t first_addr;
 vaddr_t last_addr;