[CPUFREQ] Better handling of revisionKey bits on Longhaul.

We aren't supposed to blindly copy them from another part of the same
register, but instead, only program them with values we know about.

arch/i386/kernel/cpu/cpufreq/longhaul.c

 /*
  *  $Id: longhaul.c,v 1.87 2003/02/22 10:23:46 db Exp $
  *
- *  (C) 2001  Dave Jones. <davej@suse.de>
+ *  (C) 2001-2003  Dave Jones. <davej@suse.de>
  *  (C) 2002  Padraig Brady. <padraig@antefacto.com>
  *
  *  Licensed under the terms of the GNU GPL License version 2.
@@ -294,7 +294,6 @@ static void longhaul_setstate (unsigned int clock_ratio_index)
 {
 	unsigned long lo, hi;
 	unsigned int bits;
-	int revkey;
 	int vidindex, i;
 	struct cpufreq_freqs freqs;
 	
@@ -321,11 +320,11 @@ static void longhaul_setstate (unsigned int clock_ratio_index)
 	switch (longhaul) {
 	case 1:
 		rdmsr (MSR_VIA_BCR2, lo, hi);
-		revkey = (lo & 0xf)<<4; /* Rev key. */
+		/* Enable software clock multiplier */
+		lo |= (1<<19);
+		/* desired multiplier */
 		lo &= ~(1<<23|1<<24|1<<25|1<<26);
-		lo |= (1<<19);		/* Enable software clock multiplier */
-		lo |= (bits<<23);	/* desired multiplier */
-		lo |= revkey;
+		lo |= (bits<<23);
 		wrmsr (MSR_VIA_BCR2, lo, hi);
 
 		__hlt();
@@ -333,17 +332,17 @@ static void longhaul_setstate (unsigned int clock_ratio_index)
 		/* Disable software clock multiplier */
 		rdmsr (MSR_VIA_BCR2, lo, hi);
 		lo &= ~(1<<19);
-		lo |= revkey;
 		wrmsr (MSR_VIA_BCR2, lo, hi);
 		break;
 
 	case 2:
 		rdmsr (MSR_VIA_LONGHAUL, lo, hi);
-		revkey = (lo & 0xf)<<4;	/* Rev key. */
 		lo &= 0xfff0bf0f;	/* reset [19:16,14](bus ratio) and [7:4](rev key) to 0 */
 		lo |= (bits<<16);
 		lo |= (1<<8);	/* EnableSoftBusRatio */
-		lo |= revkey;
+		/* We must program the revision key only with values we
+		 * know about, not blindly copy it from 0:3 */
+		lo |= 1;
 
 		if (can_scale_voltage) {
 			/* PB: TODO fix this up */
@@ -374,24 +373,25 @@ static void longhaul_setstate (unsigned int clock_ratio_index)
 		lo &= ~(1<<8);
 		if (can_scale_voltage)
 			lo &= ~(1<<9);
-		lo |= revkey;
+		lo |= 1;	/* Revision Key */
 		wrmsr (MSR_VIA_LONGHAUL, lo, hi);
 		break;
 
 	case 3:
 		rdmsr (MSR_VIA_LONGHAUL, lo, hi);
-		revkey = (lo & 0xf)<<4;	/* Rev key. */
 		lo &= 0xfff0bf0f;	/* reset longhaul[19:16,14] to 0 */
 		lo |= (bits<<16);
 		lo |= (1<<8);	/* EnableSoftBusRatio */
-		lo |= revkey;
+		/* We must program the revision key only with values we
+		 * know about, not blindly copy it from 0:3 */
+		lo |= 3;	/* SoftVID & SoftBSEL */
 
 		wrmsr (MSR_VIA_LONGHAUL, lo, hi);
 		__hlt();
 
 		rdmsr (MSR_VIA_LONGHAUL, lo, hi);
 		lo &= ~(1<<8);
-		lo |= revkey;
+		lo |= 3;
 		wrmsr (MSR_VIA_LONGHAUL, lo, hi);
 		break;
 	}
@@ -471,7 +471,6 @@ static void __init longhaul_setup_voltagescaling (unsigned long lo, unsigned lon
 {
 	int revkey;
 
-
 	minvid = (hi & (1<<20|1<<21|1<<22|1<<23|1<<24)) >> 20; /* 56:52 */
 	maxvid = (hi & (1<<4|1<<5|1<<6|1<<7|1<<8)) >> 4;       /* 40:36 */
 	vrmrev = (lo & (1<<15))>>15;
@@ -503,9 +502,9 @@ static void __init longhaul_setup_voltagescaling (unsigned long lo, unsigned lon
 	/* Current voltage isn't readable at first, so we need to
 	   set it to a known value. The spec says to use maxvid */
 	revkey = (lo & 0xf)<<4;	/* Rev key. */
+	lo |= revkey;		/* Reinsert key FIXME: This is bad. */
 	lo &= 0xfe0fff0f;	/* Mask unneeded bits */
 	lo |= (1<<9);		/* EnableSoftVID */
-	lo |= revkey;		/* Reinsert key */
 	lo |= maxvid << 20;
 	wrmsr (MSR_VIA_LONGHAUL, lo, hi);
 	minvid = voltage_table[minvid];