This commit gives support for the Rise mP6 CPU. It has two changes:

	1. Rise is recognized in identdcpu.c.
	2. The TSC is not written to. A workaround for the CPU bug is being
	   applied to clock.c (the bug being that the mP6 has TSC enabled
	   in its CPUID-capabilities, but it only supports reading it. If we
	   try to write to it (MSR 16), a GPF occurs.) The new behavior is that
	   FreeBSD will _not_ zero the TSC. Instead, we do a bit of 64-bit
	   arithmetic.

Reviewed by:	msmith
Obtained from:	unfurl & msmith

1 files changed, 7 insertions, 5 deletions

diff --git a/sys/isa/atrtc.c b/sys/isa/atrtc.c
index 6b787b80b80b..9fb163fa8643 100644
--- a/sys/isa/atrtc.c
+++ b/sys/isa/atrtc.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)clock.c	7.2 (Berkeley) 5/12/91
- *	$Id: clock.c,v 1.135 1999/05/29 06:57:55 phk Exp $
+ *	$Id: clock.c,v 1.136 1999/05/31 18:35:59 dfr Exp $
  */
 
 /*
@@ -585,6 +585,7 @@ readrtc(int port)
 static u_int
 calibrate_clocks(void)
 {
+	u_int64_t old_tsc;
 	u_int count, prev_count, tot_count;
 	int sec, start_sec, timeout;
 
@@ -623,7 +624,7 @@ calibrate_clocks(void)
 	tot_count = 0;
 
 	if (tsc_present) 
-		wrmsr(0x10, 0LL);	/* XXX 0x10 is the MSR for the TSC */
+		old_tsc = rdtsc();
 
 	/*
 	 * Wait for the mc146818A seconds counter to change.  Read the i8254
@@ -658,7 +659,7 @@ calibrate_clocks(void)
 	 * similar to those for the i8254 clock.
 	 */
 	if (tsc_present) 
-		tsc_freq = rdtsc();
+		tsc_freq = rdtsc() - old_tsc;
 
 	if (bootverbose) {
 		if (tsc_present)
@@ -762,9 +763,10 @@ startrtclock()
 		 * clock failed.  Do a less accurate calibration relative
 		 * to the i8254 clock.
 		 */
-		wrmsr(0x10, 0LL);	/* XXX */
+		u_int64_t old_tsc = rdtsc();
+
 		DELAY(1000000);
-		tsc_freq = rdtsc();
+		tsc_freq = rdtsc() - old_tsc;
 #ifdef CLK_USE_TSC_CALIBRATION
 		if (bootverbose)
 			printf("TSC clock: %u Hz (Method B)\n", tsc_freq);