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-rw-r--r--arch/x86/include/asm/tsc.h2
-rw-r--r--arch/x86/kernel/tsc.c7
-rw-r--r--arch/x86/kernel/tsc_msr.c28
3 files changed, 17 insertions, 20 deletions
diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h
index 57ae63cd6ee2..94605c0e9cee 100644
--- a/arch/x86/include/asm/tsc.h
+++ b/arch/x86/include/asm/tsc.h
@@ -66,6 +66,6 @@ extern void tsc_save_sched_clock_state(void);
66extern void tsc_restore_sched_clock_state(void); 66extern void tsc_restore_sched_clock_state(void);
67 67
68/* MSR based TSC calibration for Intel Atom SoC platforms */ 68/* MSR based TSC calibration for Intel Atom SoC platforms */
69int try_msr_calibrate_tsc(unsigned long *fast_calibrate); 69unsigned long try_msr_calibrate_tsc(void);
70 70
71#endif /* _ASM_X86_TSC_H */ 71#endif /* _ASM_X86_TSC_H */
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index acb3b606613e..cfbe99f88830 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -653,13 +653,10 @@ unsigned long native_calibrate_tsc(void)
653 653
654 /* Calibrate TSC using MSR for Intel Atom SoCs */ 654 /* Calibrate TSC using MSR for Intel Atom SoCs */
655 local_irq_save(flags); 655 local_irq_save(flags);
656 i = try_msr_calibrate_tsc(&fast_calibrate); 656 fast_calibrate = try_msr_calibrate_tsc();
657 local_irq_restore(flags); 657 local_irq_restore(flags);
658 if (i >= 0) { 658 if (fast_calibrate)
659 if (i == 0)
660 pr_warn("Fast TSC calibration using MSR failed\n");
661 return fast_calibrate; 659 return fast_calibrate;
662 }
663 660
664 local_irq_save(flags); 661 local_irq_save(flags);
665 fast_calibrate = quick_pit_calibrate(); 662 fast_calibrate = quick_pit_calibrate();
diff --git a/arch/x86/kernel/tsc_msr.c b/arch/x86/kernel/tsc_msr.c
index 8b5434f4389f..5dfff5809e74 100644
--- a/arch/x86/kernel/tsc_msr.c
+++ b/arch/x86/kernel/tsc_msr.c
@@ -77,21 +77,18 @@ static int match_cpu(u8 family, u8 model)
77 77
78/* 78/*
79 * Do MSR calibration only for known/supported CPUs. 79 * Do MSR calibration only for known/supported CPUs.
80 * Return values: 80 *
81 * -1: CPU is unknown/unsupported for MSR based calibration 81 * Returns the calibration value or 0 if MSR calibration failed.
82 * 0: CPU is known/supported, but calibration failed
83 * 1: CPU is known/supported, and calibration succeeded
84 */ 82 */
85int try_msr_calibrate_tsc(unsigned long *fast_calibrate) 83unsigned long try_msr_calibrate_tsc(void)
86{ 84{
87 int cpu_index;
88 u32 lo, hi, ratio, freq_id, freq; 85 u32 lo, hi, ratio, freq_id, freq;
86 unsigned long res;
87 int cpu_index;
89 88
90 cpu_index = match_cpu(boot_cpu_data.x86, boot_cpu_data.x86_model); 89 cpu_index = match_cpu(boot_cpu_data.x86, boot_cpu_data.x86_model);
91 if (cpu_index < 0) 90 if (cpu_index < 0)
92 return -1; 91 return 0;
93
94 *fast_calibrate = 0;
95 92
96 if (freq_desc_tables[cpu_index].msr_plat) { 93 if (freq_desc_tables[cpu_index].msr_plat) {
97 rdmsr(MSR_PLATFORM_INFO, lo, hi); 94 rdmsr(MSR_PLATFORM_INFO, lo, hi);
@@ -103,7 +100,7 @@ int try_msr_calibrate_tsc(unsigned long *fast_calibrate)
103 pr_info("Maximum core-clock to bus-clock ratio: 0x%x\n", ratio); 100 pr_info("Maximum core-clock to bus-clock ratio: 0x%x\n", ratio);
104 101
105 if (!ratio) 102 if (!ratio)
106 return 0; 103 goto fail;
107 104
108 /* Get FSB FREQ ID */ 105 /* Get FSB FREQ ID */
109 rdmsr(MSR_FSB_FREQ, lo, hi); 106 rdmsr(MSR_FSB_FREQ, lo, hi);
@@ -112,16 +109,19 @@ int try_msr_calibrate_tsc(unsigned long *fast_calibrate)
112 pr_info("Resolved frequency ID: %u, frequency: %u KHz\n", 109 pr_info("Resolved frequency ID: %u, frequency: %u KHz\n",
113 freq_id, freq); 110 freq_id, freq);
114 if (!freq) 111 if (!freq)
115 return 0; 112 goto fail;
116 113
117 /* TSC frequency = maximum resolved freq * maximum resolved bus ratio */ 114 /* TSC frequency = maximum resolved freq * maximum resolved bus ratio */
118 *fast_calibrate = freq * ratio; 115 res = freq * ratio;
119 pr_info("TSC runs at %lu KHz\n", *fast_calibrate); 116 pr_info("TSC runs at %lu KHz\n", res);
120 117
121#ifdef CONFIG_X86_LOCAL_APIC 118#ifdef CONFIG_X86_LOCAL_APIC
122 lapic_timer_frequency = (freq * 1000) / HZ; 119 lapic_timer_frequency = (freq * 1000) / HZ;
123 pr_info("lapic_timer_frequency = %d\n", lapic_timer_frequency); 120 pr_info("lapic_timer_frequency = %d\n", lapic_timer_frequency);
124#endif 121#endif
122 return res;
125 123
126 return 1; 124fail:
125 pr_warn("Fast TSC calibration using MSR failed\n");
126 return 0;
127} 127}