[PATCH] Longhaul - Always guess FSB

[PATCH] Longhaul - Always guess FSB

[Rafał Bilski]

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>

---

diff --git a/arch/i386/kernel/cpu/cpufreq/longhaul.c b/arch/i386/kernel/cpu/cpufreq/longhaul.c
--- a/arch/i386/kernel/cpu/cpufreq/longhaul.c
+++ b/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;
 	}


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