diff options
author | Stefan Reinauer <reinauer@chromium.org> | 2012-04-03 16:11:02 -0700 |
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committer | Stefan Reinauer <stefan.reinauer@coreboot.org> | 2012-04-05 23:35:13 +0200 |
commit | 5b6404e4195157eac8d97ae5bf30f45612109d57 (patch) | |
tree | 8e6998db4f8b3c98876b610882596ba67c9a152c /src/cpu/x86/lapic | |
parent | cab72d9b7b4bec1ee9464ed565edf7b192ef5c69 (diff) | |
download | coreboot-5b6404e4195157eac8d97ae5bf30f45612109d57.tar.xz |
Fix timer frequency detection on Sandybridge
Change-Id: Ide720bd91cde56a0afdd231d93500c371b1ffbe8
Signed-off-by: Duncan Laurie <dlaurie@google.com>
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: http://review.coreboot.org/870
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
Tested-by: build bot (Jenkins)
Diffstat (limited to 'src/cpu/x86/lapic')
-rw-r--r-- | src/cpu/x86/lapic/apic_timer.c | 48 |
1 files changed, 36 insertions, 12 deletions
diff --git a/src/cpu/x86/lapic/apic_timer.c b/src/cpu/x86/lapic/apic_timer.c index 826f5b6ad4..bb6cca7d9a 100644 --- a/src/cpu/x86/lapic/apic_timer.c +++ b/src/cpu/x86/lapic/apic_timer.c @@ -20,6 +20,7 @@ #include <stdint.h> #include <delay.h> +#include <arch/cpu.h> #include <cpu/x86/msr.h> #include <cpu/x86/lapic.h> @@ -27,14 +28,40 @@ * memory init. */ -#define FSB_CLOCK_STS 0xcd +static u32 timer_fsb = 0; -static u32 timer_fsb = 200; // default to 200MHz +static int set_timer_fsb(void) +{ + struct cpuinfo_x86 c; + int core_fsb[8] = { -1, 133, -1, 166, -1, 100, -1, -1 }; + int core2_fsb[8] = { 266, 133, 200, 166, -1, 100, -1, -1 }; + + get_fms(&c, cpuid_eax(1)); + if (c.x86 != 6) + return -1; + + switch (c.x86_model) { + case 0xe: /* Core Solo/Duo */ + case 0x1c: /* Atom */ + timer_fsb = core_fsb[rdmsr(0xcd).lo & 7]; + break; + case 0xf: /* Core 2*/ + case 0x17: /* Enhanced Core */ + timer_fsb = core2_fsb[rdmsr(0xcd).lo & 7]; + break; + case 0x2a: /* SandyBridge BCLK fixed at 100MHz*/ + timer_fsb = 100; + break; + default: + timer_fsb = 200; + break; + } + + return 0; +} void init_timer(void) { - msr_t fsb_clock_sts; - /* Set the apic timer to no interrupts and periodic mode */ lapic_write(LAPIC_LVTT, (LAPIC_LVT_TIMER_PERIODIC | LAPIC_LVT_MASKED)); @@ -45,19 +72,16 @@ void init_timer(void) lapic_write(LAPIC_TMICT, 0xffffffff); /* 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; - } + set_timer_fsb(); } void udelay(u32 usecs) { u32 start, value, ticks; + + if (!timer_fsb) + init_timer(); + /* Calculate the number of ticks to run, our FSB runs at timer_fsb Mhz */ ticks = usecs * timer_fsb; start = lapic_read(LAPIC_TMCCT); |