Enable use of the RTC chip for the statistical clock. While this does

not provide the full accuracy of a randomized statistical clock, it does
provide greater accuracy than the previous method, while not significantly
increasing overhead.  It also provides profiling support at 1024 Hz.

You must re-compile config before making a new kernel, or you will end
up with unresolved symbols.

Reviewed uy:	Bruce evans said it worked for him.

5 files changed, 137 insertions, 12 deletions

diff --git a/sys/i386/i386/tsc.c b/sys/i386/i386/tsc.c
index cf0a7f6..35f2e42 100644
--- a/sys/i386/i386/tsc.c
+++ b/sys/i386/i386/tsc.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)clock.c	7.2 (Berkeley) 5/12/91
- *	$Id: clock.c,v 1.12 1994/08/11 00:28:24 wollman Exp $
+ *	$Id: clock.c,v 1.13 1994/08/13 03:49:56 wollman Exp $
  */
 
 /*
@@ -60,6 +60,7 @@
 #define TIMER_DIV(x) ((TIMER_FREQ+(x)/2)/(x))
 
 void hardclock();
+void statclock();
 static 	int beeping;
 int 	timer0_divisor = TIMER_DIV(100);	/* XXX should be hz */
 u_int 	timer0_prescale;
@@ -102,6 +103,44 @@ clkintr(frame)
 	hardclock(&frame);
 }
 
+static u_char rtc_statusa = RTCSA_DIVIDER | RTCSA_NOPROF;
+
+/*
+ * This routine receives statistical clock interrupts from the RTC.
+ * As explained above, these occur at 128 interrupts per second.
+ * When profiling, we receive interrupts at a rate of 1024 Hz.
+ *
+ * This does not actually add as much overhead as it sounds, because
+ * when the statistical clock is active, the hardclock driver no longer
+ * needs to keep (inaccurate) statistics on its own.  This decouples
+ * statistics gathering from scheduling interrupts.
+ *
+ * The RTC chip requires that we read status register C (RTC_INTR)
+ * to acknowledge an interrupt, before it will generate the next one.
+ */
+void
+rtcintr(struct clockframe frame)
+{
+	u_char stat;
+	stat = rtcin(RTC_INTR);
+	if(stat & RTCIR_PERIOD) {
+		statclock(&frame);
+	}
+}
+
+#ifdef DEBUG
+void
+printrtc(void)
+{
+	outb(IO_RTC, RTC_STATUSA);
+	printf("RTC status A = %x", inb(IO_RTC+1));
+	outb(IO_RTC, RTC_STATUSB);
+	printf(", B = %x", inb(IO_RTC+1));
+	outb(IO_RTC, RTC_INTR);
+	printf(", C = %x\n", inb(IO_RTC+1));
+}
+#endif
+
 #if 0
 void
 timerintr(struct clockframe frame)
@@ -338,9 +377,9 @@ startrtclock()
 
 	/* initialize brain-dead battery powered clock */
 	outb (IO_RTC, RTC_STATUSA);
-	outb (IO_RTC+1, 0x26);
+	outb (IO_RTC+1, rtc_statusa);
 	outb (IO_RTC, RTC_STATUSB);
-	outb (IO_RTC+1, 2);
+	outb (IO_RTC+1, RTCSB_24HR);
 
 	outb (IO_RTC, RTC_DIAG);
 	if (s = inb (IO_RTC+1))
@@ -460,13 +499,17 @@ test_inittodr(time_t base)
  */
 #define V(s)	__CONCAT(V, s)
 extern void V(clk)();
-
+extern void V(rtc)();
 
 void
 enablertclock() 
 {
 	setidt(ICU_OFFSET+0, &V(clk), SDT_SYS386IGT, SEL_KPL);
 	INTREN(IRQ0);
+	setidt(ICU_OFFSET+8, &V(rtc), SDT_SYS386IGT, SEL_KPL);
+	INTREN(IRQ8);
+	outb(IO_RTC, RTC_STATUSB);
+	outb(IO_RTC+1, RTCSB_PINTR | RTCSB_24HR);
 }
 
 
@@ -482,10 +525,19 @@ spinwait(int millisecs)
 void
 cpu_initclocks()
 {
+	stathz = RTC_NOPROFRATE;
+	profhz = RTC_PROFRATE;
 	enablertclock();
 }
 
 void
 setstatclockrate(int newhz)
 {
+	if(newhz == RTC_PROFRATE) {
+		rtc_statusa = RTCSA_DIVIDER | RTCSA_PROF;
+	} else {
+		rtc_statusa = RTCSA_DIVIDER | RTCSA_NOPROF;
+	}
+	outb(IO_RTC, RTC_STATUSA);
+	outb(IO_RTC+1, rtc_statusa);
 }
diff --git a/sys/i386/include/spl.h b/sys/i386/include/spl.h
index 739fc20..2a9c1dc 100644
--- a/sys/i386/include/spl.h
+++ b/sys/i386/include/spl.h
@@ -30,7 +30,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id$
+ *	$Id: spl.h,v 1.3 1994/08/02 07:39:06 davidg Exp $
  */
 
 #ifndef _MACHINE_IPL_H_
@@ -79,6 +79,7 @@ extern	unsigned net_imask;	/* group of interrupts masked with splimp() */
 extern	volatile unsigned ipending;	/* active interrupts masked by cpl */
 extern	volatile unsigned netisr;
 extern	unsigned tty_imask;	/* group of interrupts masked with spltty() */
+extern  unsigned stat_imask;	/* interrupts masked with splstatclock() */
 
 /*
  * ipending has to be volatile so that it is read every time it is accessed
@@ -110,7 +111,7 @@ static __inline int name(void)			\
 GENSPL(splbio, cpl |= bio_imask)
 GENSPL(splclock, cpl = HWI_MASK | SWI_MASK)
 GENSPL(splhigh, cpl = HWI_MASK | SWI_MASK)
-GENSPL(splstatclock, cpl = HWI_MASK | SWI_MASK)
+GENSPL(splstatclock, cpl |= stat_imask | SWI_CLOCK_MASK)
 GENSPL(splimp, cpl |= net_imask)
 GENSPL(splnet, cpl |= SWI_NET_MASK)
 GENSPL(splsoftclock, cpl = SWI_CLOCK_MASK)
diff --git a/sys/i386/isa/clock.c b/sys/i386/isa/clock.c
index cf0a7f6..35f2e42 100644
--- a/sys/i386/isa/clock.c
+++ b/sys/i386/isa/clock.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)clock.c	7.2 (Berkeley) 5/12/91
- *	$Id: clock.c,v 1.12 1994/08/11 00:28:24 wollman Exp $
+ *	$Id: clock.c,v 1.13 1994/08/13 03:49:56 wollman Exp $
  */
 
 /*
@@ -60,6 +60,7 @@
 #define TIMER_DIV(x) ((TIMER_FREQ+(x)/2)/(x))
 
 void hardclock();
+void statclock();
 static 	int beeping;
 int 	timer0_divisor = TIMER_DIV(100);	/* XXX should be hz */
 u_int 	timer0_prescale;
@@ -102,6 +103,44 @@ clkintr(frame)
 	hardclock(&frame);
 }
 
+static u_char rtc_statusa = RTCSA_DIVIDER | RTCSA_NOPROF;
+
+/*
+ * This routine receives statistical clock interrupts from the RTC.
+ * As explained above, these occur at 128 interrupts per second.
+ * When profiling, we receive interrupts at a rate of 1024 Hz.
+ *
+ * This does not actually add as much overhead as it sounds, because
+ * when the statistical clock is active, the hardclock driver no longer
+ * needs to keep (inaccurate) statistics on its own.  This decouples
+ * statistics gathering from scheduling interrupts.
+ *
+ * The RTC chip requires that we read status register C (RTC_INTR)
+ * to acknowledge an interrupt, before it will generate the next one.
+ */
+void
+rtcintr(struct clockframe frame)
+{
+	u_char stat;
+	stat = rtcin(RTC_INTR);
+	if(stat & RTCIR_PERIOD) {
+		statclock(&frame);
+	}
+}
+
+#ifdef DEBUG
+void
+printrtc(void)
+{
+	outb(IO_RTC, RTC_STATUSA);
+	printf("RTC status A = %x", inb(IO_RTC+1));
+	outb(IO_RTC, RTC_STATUSB);
+	printf(", B = %x", inb(IO_RTC+1));
+	outb(IO_RTC, RTC_INTR);
+	printf(", C = %x\n", inb(IO_RTC+1));
+}
+#endif
+
 #if 0
 void
 timerintr(struct clockframe frame)
@@ -338,9 +377,9 @@ startrtclock()
 
 	/* initialize brain-dead battery powered clock */
 	outb (IO_RTC, RTC_STATUSA);
-	outb (IO_RTC+1, 0x26);
+	outb (IO_RTC+1, rtc_statusa);
 	outb (IO_RTC, RTC_STATUSB);
-	outb (IO_RTC+1, 2);
+	outb (IO_RTC+1, RTCSB_24HR);
 
 	outb (IO_RTC, RTC_DIAG);
 	if (s = inb (IO_RTC+1))
@@ -460,13 +499,17 @@ test_inittodr(time_t base)
  */
 #define V(s)	__CONCAT(V, s)
 extern void V(clk)();
-
+extern void V(rtc)();
 
 void
 enablertclock() 
 {
 	setidt(ICU_OFFSET+0, &V(clk), SDT_SYS386IGT, SEL_KPL);
 	INTREN(IRQ0);
+	setidt(ICU_OFFSET+8, &V(rtc), SDT_SYS386IGT, SEL_KPL);
+	INTREN(IRQ8);
+	outb(IO_RTC, RTC_STATUSB);
+	outb(IO_RTC+1, RTCSB_PINTR | RTCSB_24HR);
 }
 
 
@@ -482,10 +525,19 @@ spinwait(int millisecs)
 void
 cpu_initclocks()
 {
+	stathz = RTC_NOPROFRATE;
+	profhz = RTC_PROFRATE;
 	enablertclock();
 }
 
 void
 setstatclockrate(int newhz)
 {
+	if(newhz == RTC_PROFRATE) {
+		rtc_statusa = RTCSA_DIVIDER | RTCSA_PROF;
+	} else {
+		rtc_statusa = RTCSA_DIVIDER | RTCSA_NOPROF;
+	}
+	outb(IO_RTC, RTC_STATUSA);
+	outb(IO_RTC+1, rtc_statusa);
 }
diff --git a/sys/i386/isa/icu.s b/sys/i386/isa/icu.s
index 6d897d7..735eeda 100644
--- a/sys/i386/isa/icu.s
+++ b/sys/i386/isa/icu.s
@@ -36,7 +36,7 @@
  *
  *	@(#)icu.s	7.2 (Berkeley) 5/21/91
  *
- *	$Id: icu.s,v 1.9 1994/05/25 08:58:55 rgrimes Exp $
+ *	$Id: icu.s,v 1.10 1994/08/13 03:50:01 wollman Exp $
  */
 
 /*
@@ -58,6 +58,8 @@ _cpl:	.long	HWI_MASK | SWI_MASK	/* current priority (all off) */
 	.globl	_imen
 _imen:	.long	HWI_MASK		/* interrupt mask enable (all h/w off) */
 _high_imask:	.long	HWI_MASK | SWI_MASK
+	.globl  _stat_imask
+_stat_imask:	.long	(1 << 8)
 	.globl	_tty_imask
 _tty_imask:	.long	0
 	.globl	_bio_imask
diff --git a/sys/i386/isa/rtc.h b/sys/i386/isa/rtc.h
index ba008b6..9c0f501 100644
--- a/sys/i386/isa/rtc.h
+++ b/sys/i386/isa/rtc.h
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)rtc.h	7.1 (Berkeley) 5/12/91
- *	$Id: rtc.h,v 1.3 1993/11/07 17:44:34 wollman Exp $
+ *	$Id: rtc.h,v 1.4 1993/12/18 01:12:47 ache Exp $
  */
 
 #ifndef _I386_ISA_RTC_H_
@@ -54,10 +54,28 @@
 #define RTC_DAY		0x07	/* day of month */
 #define RTC_MONTH	0x08	/* month of year */
 #define RTC_YEAR	0x09	/* month of year */
+
 #define RTC_STATUSA	0x0a	/* status register A */
 #define  RTCSA_TUP	 0x80	/* time update, don't look now */
+#define  RTCSA_DIVIDER   0x20   /* divider correct for 32768 Hz */
+#define  RTCSA_8192      0x03
+#define  RTCSA_4096      0x04
+#define  RTCSA_2048      0x05
+#define  RTCSA_1024      0x06	/* default for profiling */
+#define  RTCSA_PROF      RTCSA_1024
+#define  RTC_PROFRATE    1024
+#define  RTCSA_512       0x07
+#define  RTCSA_256       0x08
+#define  RTCSA_128       0x09
+#define  RTCSA_NOPROF	 RTCSA_128
+#define  RTC_NOPROFRATE  128
+#define  RTCSA_64        0x0a
+#define  RTCSA_32        0x0b
 
 #define RTC_STATUSB	0x0b	/* status register B */
+#define  RTCSB_HALT      0x80	/* stop clock updates */
+#define  RTCSB_PINTR     0x40	/* periodic clock interrupt */
+#define  RTCSB_24HR      0x02	/* 24-hour mode */
 
 #define RTC_INTR	0x0c	/* status register C (R) interrupt source */
 #define  RTCIR_UPDATE	 0x10	/* update intr */