[coreboot] New patch to review for coreboot: 05634a9 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/507

-gerrit

commit 05634a9703cb7c52a882a67669800e79a5101e99
Author: Vikram Narayanan 
Date:   Mon Dec 26 23:30:23 2011 +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.
    Also, fixed the indentations.

Change-Id: I6bf93bac1ee9123af78c003f5a0728f8f0801958
    Signed-off-by: Vikram Narayanan 
---
 src/cpu/x86/lapic/apic_timer.c |   31 +++++++++++++++++++++----------
 1 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/src/cpu/x86/lapic/apic_timer.c b/src/cpu/x86/lapic/apic_timer.c
index 826f5b6..312951a 100644
--- a/src/cpu/x86/lapic/apic_timer.c
+++ b/src/cpu/x86/lapic/apic_timer.c
@@ -27,9 +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)
 {
@@ -42,16 +43,26 @@ void init_timer(void)
    lapic_write(LAPIC_TDCR, LAPIC_TDR_DIV_1);

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

/* Set FSB frequency to a reasonable value */
    fsb_clock_sts = rdmsr(FSB_CLOCK_STS);
-	switch ((fsb_clock_sts.lo >> 4) & 0x07) {
-	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;
+	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;
    }
 }

@@ -63,5 +74,5 @@ void udelay(u32 usecs)
    start = lapic_read(LAPIC_TMCCT);
    do {
    	value = lapic_read(LAPIC_TMCCT);
-	} while((start - value) < ticks);
+	} while ((start - value) < ticks);
 }