[CPUFREQ] Longhaul - Always guess FSB

This is patch that solves Ebox mini PC issue and make
FSB code more specification compilant. At start guess_fsb
function is guessing 200MHz FSB too. It is better to
make it in this way because, thanks to this function, driver
will fail for bogus FSB values caused by bogus multiplier
value. For PowerSaver processors we can't depend on Max /
MinMHzFSB because these values are only used for
PowerSaver 2.0 and 3.0. Most processors on which Longhaul
is used are PowerSaver 1.0 only. I'm changing code for older
CPU's too, but not so much as previously, and this code was
already used for Ezra. Using MinMHzBR for Ezra-T is outside
spec. It is for voltage scaling purpose and don't have to
be equal to minmult (but it is). Same for Nehemiah (it
isn't for sure). Added mult - current multiplier value.
Signed-off-by: Rafa³ Bilski <rafalbilski@interia.pl>
Signed-off-by: Dave Jones <davej@redhat.com>

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

@@ -318,12 +318,12 @@ static void longhaul_setstate(unsigned int clock_ratio_index)
 
 #define ROUNDING	0xf
 
-static int _guess(int guess)
+static int _guess(int guess, int mult)
 {
 	int target;
 
-	target = ((maxmult/10)*guess);
-	if (maxmult%10 != 0)
+	target = ((mult/10)*guess);
+	if (mult%10 != 0)
 		target += (guess/2);
 	target += ROUNDING/2;
 	target &= ~ROUNDING;
@@ -331,17 +331,17 @@ static int _guess(int guess)
 }
 
 
-static int guess_fsb(void)
+static int guess_fsb(int mult)
 {
 	int speed = (cpu_khz/1000);
 	int i;
-	int speeds[3] = { 66, 100, 133 };
+	int speeds[] = { 66, 100, 133, 200 };
 
 	speed += ROUNDING/2;
 	speed &= ~ROUNDING;
 
-	for (i=0; i<3; i++) {
-		if (_guess(speeds[i]) == speed)
+	for (i=0; i<4; i++) {
+		if (_guess(speeds[i], mult) == speed)
 			return speeds[i];
 	}
 	return 0;
@@ -361,6 +361,7 @@ static int __init longhaul_get_ranges(void)
 	unsigned long lo, hi;
 	unsigned int eblcr_fsb_table_v1[] = { 66, 133, 100, -1 };
 	unsigned int eblcr_fsb_table_v2[] = { 133, 100, -1, 66 };
+	int mult;
 
 	switch (longhaul_version) {
 	case TYPE_LONGHAUL_V1:
@@ -368,30 +369,18 @@ static int __init longhaul_get_ranges(void)
 		/* Ugh, Longhaul v1 didn't have the min/max MSRs.
 		   Assume min=3.0x & max = whatever we booted at. */
 		minmult = 30;
-		maxmult = longhaul_get_cpu_mult();
-		rdmsr (MSR_IA32_EBL_CR_POWERON, lo, hi);
-		invalue = (lo & (1<<18|1<<19)) >>18;
-		if (cpu_model==CPU_SAMUEL || cpu_model==CPU_SAMUEL2)
-			fsb = eblcr_fsb_table_v1[invalue];
-		else
-			fsb = guess_fsb();
+		maxmult = mult = longhaul_get_cpu_mult();
 		break;
 
 	case TYPE_POWERSAVER:
 		/* Ezra-T */
 		if (cpu_model==CPU_EZRA_T) {
+			minmult = 30;
 			rdmsrl (MSR_VIA_LONGHAUL, longhaul.val);
 			invalue = longhaul.bits.MaxMHzBR;
 			if (longhaul.bits.MaxMHzBR4)
 				invalue += 16;
-			maxmult=ezra_t_multipliers[invalue];
-
-			invalue = longhaul.bits.MinMHzBR;
-			if (longhaul.bits.MinMHzBR4 == 1)
-				minmult = 30;
-			else
-				minmult = ezra_t_multipliers[invalue];
-			fsb = eblcr_fsb_table_v2[longhaul.bits.MaxMHzFSB];
+			maxmult = mult = ezra_t_multipliers[invalue];
 			break;
 		}
 
@@ -411,21 +400,16 @@ static int __init longhaul_get_ranges(void)
 			 *   But it works, so we don't grumble.
 			 */
 			minmult=40;
-			maxmult=longhaul_get_cpu_mult();
-
-			/* Starting with the 1.2GHz parts, theres a 200MHz bus. */
-			if ((cpu_khz/maxmult) > 13400)
-				fsb = 200;
-			else
-				fsb = eblcr_fsb_table_v2[longhaul.bits.MaxMHzFSB];
+			maxmult = mult = longhaul_get_cpu_mult();
 			break;
 		}
 	}
+	fsb = guess_fsb(mult);
 
 	dprintk ("MinMult:%d.%dx MaxMult:%d.%dx\n",
 		 minmult/10, minmult%10, maxmult/10, maxmult%10);
 
-	if (fsb == -1) {
+	if (fsb == 0) {
 		printk (KERN_INFO PFX "Invalid (reserved) FSB!\n");
 		return -EINVAL;
 	}