x86, tsc: Remove CPU frequency calibration on AMD

[pandora-kernel.git] / arch / x86 / kernel / tsc.c

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index ce8e502..13b6a6c 100644 (file)
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -854,60 +854,6 @@ static void __init init_tsc_clocksource(void)
        clocksource_register_khz(&clocksource_tsc, tsc_khz);
 }
 
-#ifdef CONFIG_X86_64
-/*
- * calibrate_cpu is used on systems with fixed rate TSCs to determine
- * processor frequency
- */
-#define TICK_COUNT 100000000
-static unsigned long __init calibrate_cpu(void)
-{
-       int tsc_start, tsc_now;
-       int i, no_ctr_free;
-       unsigned long evntsel3 = 0, pmc3 = 0, pmc_now = 0;
-       unsigned long flags;
-
-       for (i = 0; i < 4; i++)
-               if (avail_to_resrv_perfctr_nmi_bit(i))
-                       break;
-       no_ctr_free = (i == 4);
-       if (no_ctr_free) {
-               WARN(1, KERN_WARNING "Warning: AMD perfctrs busy ... "
-                    "cpu_khz value may be incorrect.\n");
-               i = 3;
-               rdmsrl(MSR_K7_EVNTSEL3, evntsel3);
-               wrmsrl(MSR_K7_EVNTSEL3, 0);
-               rdmsrl(MSR_K7_PERFCTR3, pmc3);
-       } else {
-               reserve_perfctr_nmi(MSR_K7_PERFCTR0 + i);
-               reserve_evntsel_nmi(MSR_K7_EVNTSEL0 + i);
-       }
-       local_irq_save(flags);
-       /* start measuring cycles, incrementing from 0 */
-       wrmsrl(MSR_K7_PERFCTR0 + i, 0);
-       wrmsrl(MSR_K7_EVNTSEL0 + i, 1 << 22 | 3 << 16 | 0x76);
-       rdtscl(tsc_start);
-       do {
-               rdmsrl(MSR_K7_PERFCTR0 + i, pmc_now);
-               tsc_now = get_cycles();
-       } while ((tsc_now - tsc_start) < TICK_COUNT);
-
-       local_irq_restore(flags);
-       if (no_ctr_free) {
-               wrmsrl(MSR_K7_EVNTSEL3, 0);
-               wrmsrl(MSR_K7_PERFCTR3, pmc3);
-               wrmsrl(MSR_K7_EVNTSEL3, evntsel3);
-       } else {
-               release_perfctr_nmi(MSR_K7_PERFCTR0 + i);
-               release_evntsel_nmi(MSR_K7_EVNTSEL0 + i);
-       }
-
-       return pmc_now * tsc_khz / (tsc_now - tsc_start);
-}
-#else
-static inline unsigned long calibrate_cpu(void) { return cpu_khz; }
-#endif
-
 void __init tsc_init(void)
 {
        u64 lpj;
@@ -926,10 +872,6 @@ void __init tsc_init(void)
                return;
        }
 
-       if (cpu_has(&boot_cpu_data, X86_FEATURE_CONSTANT_TSC) &&
-                       (boot_cpu_data.x86_vendor == X86_VENDOR_AMD))
-               cpu_khz = calibrate_cpu();
-
        printk("Detected %lu.%03lu MHz processor.\n",
                        (unsigned long)cpu_khz / 1000,
                        (unsigned long)cpu_khz % 1000);