New patch to review for coreboot: ed3a3f3 APIC: Fixed reading MSR_FSB_FREQ register

[Vikram Narayanan]

Vikram Narayanan ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/536

-gerrit

commit ed3a3f37393055b8a85929db43df46077c994320
Author: Vikram Narayanan 
Date:   Sat Jan 14 14:31:23 2012 +0530

APIC: Fixed reading MSR_FSB_FREQ register

According to Intel's manual, bits 0:2 of MSR 0xCDh gives the FSB
    frequency. But the code had a right shift of 4 which will always
    give 267 MHz, as the valid bits are shifted to right.

Change-Id: I6d24f68edb4fa3ee739d63461a17f4458c90481b
    Signed-off-by: Vikram Narayanan 
---
 src/cpu/x86/lapic/apic_timer.c |   28 +++++++++-------------------
 1 files changed, 9 insertions(+), 19 deletions(-)

diff --git a/src/cpu/x86/lapic/apic_timer.c b/src/cpu/x86/lapic/apic_timer.c
index 312951a..0b56fd5 100644
--- a/src/cpu/x86/lapic/apic_timer.c
+++ b/src/cpu/x86/lapic/apic_timer.c
@@ -27,10 +27,10 @@
  * memory init.
  */

-#define FSB_CLOCK_STS 0xCD
+#define FSB_CLOCK_STS 0xcd
 #define FSB_FREQ_MASK 0x07

-static u32 timer_fsb = 200;	// default to 200MHz
+static u32 timer_fsb = 200; // default to 200MHz

void init_timer(void)
 {
@@ -43,26 +43,16 @@ void init_timer(void)
    lapic_write(LAPIC_TDCR, LAPIC_TDR_DIV_1);

/* Set the initial counter to 0xffffffff */
-	lapic_write(LAPIC_TMICT, ~0UL);
+	lapic_write(LAPIC_TMICT, 0xffffffff);

/* Set FSB frequency to a reasonable value */
    fsb_clock_sts = rdmsr(FSB_CLOCK_STS);
    switch (fsb_clock_sts.lo & FSB_FREQ_MASK) {
-	case 0:
-		timer_fsb = 266;
-		break;
-	case 1:
-		timer_fsb = 133;
-		break;
-	case 2:
-		timer_fsb = 200;
-		break;
-	case 3:
-		timer_fsb = 166;
-		break;
-	case 5:
-		timer_fsb = 100;
-		break;
+	case 0: timer_fsb = 266; break;
+	case 1: timer_fsb = 133; break;
+	case 2: timer_fsb = 200; break;
+	case 3: timer_fsb = 166; break;
+	case 5: timer_fsb = 100; break;
    }
 }

@@ -74,5 +64,5 @@ void udelay(u32 usecs)
    start = lapic_read(LAPIC_TMCCT);
    do {
    	value = lapic_read(LAPIC_TMCCT);
-	} while ((start - value) < ticks);
+	} while((start - value) < ticks);
 }