3 files changed, 42 insertions(+), 2 deletions(-)

M pc/fns.h
M pc/i8253.c
M pc/main.c

@@ 41,10 41,11 @@ void	i8042reset(void);
 void	i8250console(void);
 void*	i8250alloc(int, int, int);
 void	i8250mouse(char*, int (*)(Queue*, int), int);
-void	i8253init(void);
 void	i8253enable(void);
-void	i8253timerset(uvlong);
+void	i8253init(void);
+void	i8253link(void);
 uvlong	i8253read(uvlong*);
+void	i8253timerset(uvlong);
 void	i8259init(void);
 int	i8259isr(int);
 int	i8259enable(Vctl*);

@@ 186,6 186,7 @@ guesscpuhz(int aalcycles)
 }
 
 ulong i8253periodset;
+int i8253dotimerset = 1;
 
 void
 i8253timerset(uvlong next)


@@ 194,6 195,9 @@ i8253timerset(uvlong next)
 	ulong want;
 	ulong now;
 
+	if(i8253dotimerset == 0)
+		return;
+
 	want = next>>Tickshift;
 	now = i8253.ticks;	/* assuming whomever called us just did fastticks() */
 


@@ 235,6 239,40 @@ i8253enable(void)
 	intrenable(IrqCLOCK, i8253clock, 0, BUSUNKNOWN, "clock");
 }
 
+static long
+i8253timerread(Chan*, void *a, long n, vlong offset)
+{
+	if(n < 16)
+		error("need more room");
+	if(offset)
+		return 0;
+	return snprint(a, n, "timerset %s", i8253dotimerset ? "on" : "off");
+}
+
+static long
+i8253timerwrite(Chan*, void *a, long n, vlong)
+{
+	if(n==3 && memcmp(a, "off", 3) == 0){
+		i8253dotimerset = 0;
+		outb(Tmode, Load0|Square);
+		outb(T0cntr, (Freq/HZ));
+		outb(T0cntr, (Freq/HZ)>>8);
+		return n;
+	}
+	if(n==2 && memcmp(a, "on", 2) == 0){
+		i8253dotimerset = 1;
+		return n;
+	}
+	error("invalid control message");
+	return -1;
+}
+
+void
+i8253link(void)
+{
+	addarchfile("i8253timerset", 0664, i8253timerread, i8253timerwrite);
+}
+
 /*
  *  return the total ticks of counter 1.  We shift by
  *  8 to give timesync more wriggle room for interpretation

@@ 105,6 105,7 @@ main(void)
 	links();
 conf.monitor = 1;
 	chandevreset();
+	i8253link();
 	pageinit();
 	swapinit();
 	userinit();