2 * "High Precision Event Timer" based timekeeping.
4 * Copyright (c) 1991,1992,1995 Linus Torvalds
5 * Copyright (c) 1994 Alan Modra
6 * Copyright (c) 1995 Markus Kuhn
7 * Copyright (c) 1996 Ingo Molnar
8 * Copyright (c) 1998 Andrea Arcangeli
9 * Copyright (c) 2002,2006 Vojtech Pavlik
10 * Copyright (c) 2003 Andi Kleen
11 * RTC support code taken from arch/i386/kernel/timers/time_hpet.c
14 #include <linux/clockchips.h>
15 #include <linux/init.h>
16 #include <linux/interrupt.h>
17 #include <linux/module.h>
18 #include <linux/time.h>
20 #include <asm/i8253.h>
23 #include <asm/vgtod.h>
25 #include <asm/timer.h>
27 volatile unsigned long __jiffies __section_jiffies
= INITIAL_JIFFIES
;
29 unsigned long profile_pc(struct pt_regs
*regs
)
31 unsigned long pc
= instruction_pointer(regs
);
33 /* Assume the lock function has either no stack frame or a copy
35 Eflags always has bits 22 and up cleared unlike kernel addresses. */
36 if (!user_mode_vm(regs
) && in_lock_functions(pc
)) {
37 #ifdef CONFIG_FRAME_POINTER
38 return *(unsigned long *)(regs
->bp
+ sizeof(long));
40 unsigned long *sp
= (unsigned long *)regs
->sp
;
49 EXPORT_SYMBOL(profile_pc
);
51 irqreturn_t
timer_interrupt(int irq
, void *dev_id
)
53 add_pda(irq0_irqs
, 1);
55 global_clock_event
->event_handler(global_clock_event
);
60 /* calibrate_cpu is used on systems with fixed rate TSCs to determine
61 * processor frequency */
62 #define TICK_COUNT 100000000
63 unsigned long __init
calibrate_cpu(void)
65 int tsc_start
, tsc_now
;
67 unsigned long evntsel3
= 0, pmc3
= 0, pmc_now
= 0;
70 for (i
= 0; i
< 4; i
++)
71 if (avail_to_resrv_perfctr_nmi_bit(i
))
73 no_ctr_free
= (i
== 4);
76 rdmsrl(MSR_K7_EVNTSEL3
, evntsel3
);
77 wrmsrl(MSR_K7_EVNTSEL3
, 0);
78 rdmsrl(MSR_K7_PERFCTR3
, pmc3
);
80 reserve_perfctr_nmi(MSR_K7_PERFCTR0
+ i
);
81 reserve_evntsel_nmi(MSR_K7_EVNTSEL0
+ i
);
83 local_irq_save(flags
);
84 /* start measuring cycles, incrementing from 0 */
85 wrmsrl(MSR_K7_PERFCTR0
+ i
, 0);
86 wrmsrl(MSR_K7_EVNTSEL0
+ i
, 1 << 22 | 3 << 16 | 0x76);
89 rdmsrl(MSR_K7_PERFCTR0
+ i
, pmc_now
);
90 tsc_now
= get_cycles();
91 } while ((tsc_now
- tsc_start
) < TICK_COUNT
);
93 local_irq_restore(flags
);
95 wrmsrl(MSR_K7_EVNTSEL3
, 0);
96 wrmsrl(MSR_K7_PERFCTR3
, pmc3
);
97 wrmsrl(MSR_K7_EVNTSEL3
, evntsel3
);
99 release_perfctr_nmi(MSR_K7_PERFCTR0
+ i
);
100 release_evntsel_nmi(MSR_K7_EVNTSEL0
+ i
);
103 return pmc_now
* tsc_khz
/ (tsc_now
- tsc_start
);
106 static struct irqaction irq0
= {
107 .handler
= timer_interrupt
,
108 .flags
= IRQF_DISABLED
| IRQF_IRQPOLL
| IRQF_NOBALANCING
,
109 .mask
= CPU_MASK_NONE
,
113 void __init
hpet_time_init(void)
118 irq0
.mask
= cpumask_of_cpu(0);
122 void __init
time_init(void)
125 if (cpu_has(&boot_cpu_data
, X86_FEATURE_RDTSCP
))
126 vgetcpu_mode
= VGETCPU_RDTSCP
;
128 vgetcpu_mode
= VGETCPU_LSL
;
130 late_time_init
= choose_time_init();