i386: add delay_fini()

Not all of the clocks with a delay(9) implementation necessarily keep
ticking across suspend/resume.  We need a clean way to reverse
delay_init() during suspend when those clocks stop ticking.

Hence, delay_fini().  delay_fini() resets delay_func() to
i8254_delay() if the given function pointer is the active delay(9)
implementation.

ok mlarkin@

2 files changed, 16 insertions, 5 deletions

diff --git a/sys/arch/i386/i386/machdep.c b/sys/arch/i386/i386/machdep.c
index 62e2c88bde7..310208ac4cd 100644
--- a/sys/arch/i386/i386/machdep.c
+++ b/sys/arch/i386/i386/machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: machdep.c,v 1.657 2022/10/30 17:43:39 guenther Exp $	*/
+/*	$OpenBSD: machdep.c,v 1.658 2022/11/08 14:49:20 cheloha Exp $	*/
 /*	$NetBSD: machdep.c,v 1.214 1996/11/10 03:16:17 thorpej Exp $	*/
 
 /*-
@@ -3973,12 +3973,22 @@ cpu_rnd_messybits(void)
 	return (ts.tv_nsec ^ (ts.tv_sec << 20));
 }
 
+int i386_delay_quality;
+
 void
 delay_init(void(*fn)(int), int fn_quality)
 {
-	static int cur_quality = 0;
-	if (fn_quality > cur_quality) {
+	if (fn_quality > i386_delay_quality) {
 		delay_func = fn;
-		cur_quality = fn_quality;
+		i386_delay_quality = fn_quality;
+	}
+}
+
+void
+delay_fini(void (*fn)(int))
+{
+	if (delay_func == fn) {
+		delay_func = i8254_delay;
+		i386_delay_quality = 0;
 	}
 }
diff --git a/sys/arch/i386/include/cpu.h b/sys/arch/i386/include/cpu.h
index 68bc3542a0f..6d707fc2d77 100644
--- a/sys/arch/i386/include/cpu.h
+++ b/sys/arch/i386/include/cpu.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.h,v 1.179 2022/08/29 02:58:13 jsg Exp $	*/
+/*	$OpenBSD: cpu.h,v 1.180 2022/11/08 14:49:20 cheloha Exp $	*/
 /*	$NetBSD: cpu.h,v 1.35 1996/05/05 19:29:26 christos Exp $	*/
 
 /*-
@@ -302,6 +302,7 @@ void signotify(struct proc *);
  * We need a machine-independent name for this.
  */
 extern void (*delay_func)(int);
+void delay_fini(void(*)(int));
 void delay_init(void(*)(int), int);
 struct timeval;