diff options
Diffstat (limited to 'arch/x86/platform/mrst/mrst.c')
| -rw-r--r-- | arch/x86/platform/mrst/mrst.c | 33 |
1 files changed, 28 insertions, 5 deletions
diff --git a/arch/x86/platform/mrst/mrst.c b/arch/x86/platform/mrst/mrst.c index 6ed7afdaf4af..b7f14e5b2c66 100644 --- a/arch/x86/platform/mrst/mrst.c +++ b/arch/x86/platform/mrst/mrst.c @@ -187,11 +187,34 @@ int __init sfi_parse_mrtc(struct sfi_table_header *table) static unsigned long __init mrst_calibrate_tsc(void) { unsigned long flags, fast_calibrate; - - local_irq_save(flags); - fast_calibrate = apbt_quick_calibrate(); - local_irq_restore(flags); - + if (__mrst_cpu_chip == MRST_CPU_CHIP_PENWELL) { + u32 lo, hi, ratio, fsb; + + rdmsr(MSR_IA32_PERF_STATUS, lo, hi); + pr_debug("IA32 perf status is 0x%x, 0x%0x\n", lo, hi); + ratio = (hi >> 8) & 0x1f; + pr_debug("ratio is %d\n", ratio); + if (!ratio) { + pr_err("read a zero ratio, should be incorrect!\n"); + pr_err("force tsc ratio to 16 ...\n"); + ratio = 16; + } + rdmsr(MSR_FSB_FREQ, lo, hi); + if ((lo & 0x7) == 0x7) + fsb = PENWELL_FSB_FREQ_83SKU; + else + fsb = PENWELL_FSB_FREQ_100SKU; + fast_calibrate = ratio * fsb; + pr_debug("read penwell tsc %lu khz\n", fast_calibrate); + lapic_timer_frequency = fsb * 1000 / HZ; + /* mark tsc clocksource as reliable */ + set_cpu_cap(&boot_cpu_data, X86_FEATURE_TSC_RELIABLE); + } else { + local_irq_save(flags); + fast_calibrate = apbt_quick_calibrate(); + local_irq_restore(flags); + } + if (fast_calibrate) return fast_calibrate; |
