diff options
| author | Dirk Brandewie | 2011-11-10 14:42:53 +0100 |
|---|---|---|
| committer | Ingo Molnar | 2011-11-10 16:20:59 +0100 |
| commit | 0a9153261d54c432bc0bdc88607f24c835ac729c (patch) | |
| tree | 25fe6a310d3f3ecb9f873c8e49c852f1f4c5abe1 /arch | |
| parent | x86/apic: Allow use of lapic timer early calibration result (diff) | |
| download | kernel-qcow2-linux-0a9153261d54c432bc0bdc88607f24c835ac729c.tar.gz kernel-qcow2-linux-0a9153261d54c432bc0bdc88607f24c835ac729c.tar.xz kernel-qcow2-linux-0a9153261d54c432bc0bdc88607f24c835ac729c.zip | |
x86/mrst: Add support for Penwell clock calibration
Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/include/asm/mrst.h | 7 | ||||
| -rw-r--r-- | arch/x86/platform/mrst/mrst.c | 33 |
2 files changed, 35 insertions, 5 deletions
diff --git a/arch/x86/include/asm/mrst.h b/arch/x86/include/asm/mrst.h index 719f00b28ff5..e6283129c821 100644 --- a/arch/x86/include/asm/mrst.h +++ b/arch/x86/include/asm/mrst.h @@ -44,6 +44,13 @@ enum mrst_timer_options { extern enum mrst_timer_options mrst_timer_options; +/* + * Penwell uses spread spectrum clock, so the freq number is not exactly + * the same as reported by MSR based on SDM. + */ +#define PENWELL_FSB_FREQ_83SKU 83200 +#define PENWELL_FSB_FREQ_100SKU 99840 + #define SFI_MTMR_MAX_NUM 8 #define SFI_MRTC_MAX 8 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; |