| /* |
| * "High Precision Event Timer" based timekeeping. |
| * |
| * Copyright (c) 1991,1992,1995 Linus Torvalds |
| * Copyright (c) 1994 Alan Modra |
| * Copyright (c) 1995 Markus Kuhn |
| * Copyright (c) 1996 Ingo Molnar |
| * Copyright (c) 1998 Andrea Arcangeli |
| * Copyright (c) 2002,2006 Vojtech Pavlik |
| * Copyright (c) 2003 Andi Kleen |
| * RTC support code taken from arch/i386/kernel/timers/time_hpet.c |
| */ |
| |
| #include <linux/clockchips.h> |
| #include <linux/init.h> |
| #include <linux/interrupt.h> |
| #include <linux/module.h> |
| #include <linux/time.h> |
| |
| #include <asm/i8253.h> |
| #include <asm/hpet.h> |
| #include <asm/nmi.h> |
| #include <asm/vgtod.h> |
| #include <asm/time.h> |
| #include <asm/timer.h> |
| |
| volatile unsigned long __jiffies __section_jiffies = INITIAL_JIFFIES; |
| |
| unsigned long profile_pc(struct pt_regs *regs) |
| { |
| unsigned long pc = instruction_pointer(regs); |
| |
| /* Assume the lock function has either no stack frame or a copy |
| of flags from PUSHF |
| Eflags always has bits 22 and up cleared unlike kernel addresses. */ |
| if (!user_mode(regs) && in_lock_functions(pc)) { |
| unsigned long *sp = (unsigned long *)regs->sp; |
| if (sp[0] >> 22) |
| return sp[0]; |
| if (sp[1] >> 22) |
| return sp[1]; |
| } |
| return pc; |
| } |
| EXPORT_SYMBOL(profile_pc); |
| |
| static irqreturn_t timer_event_interrupt(int irq, void *dev_id) |
| { |
| add_pda(irq0_irqs, 1); |
| |
| global_clock_event->event_handler(global_clock_event); |
| |
| return IRQ_HANDLED; |
| } |
| |
| /* calibrate_cpu is used on systems with fixed rate TSCs to determine |
| * processor frequency */ |
| #define TICK_COUNT 100000000 |
| unsigned long __init native_calculate_cpu_khz(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) { |
| 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 meauring 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_sync(); |
| } 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); |
| } |
| |
| static struct irqaction irq0 = { |
| .handler = timer_event_interrupt, |
| .flags = IRQF_DISABLED | IRQF_IRQPOLL | IRQF_NOBALANCING, |
| .mask = CPU_MASK_NONE, |
| .name = "timer" |
| }; |
| |
| void __init hpet_time_init(void) |
| { |
| if (!hpet_enable()) |
| setup_pit_timer(); |
| |
| setup_irq(0, &irq0); |
| } |
| |
| void __init time_init(void) |
| { |
| tsc_calibrate(); |
| |
| cpu_khz = tsc_khz; |
| if (cpu_has(&boot_cpu_data, X86_FEATURE_CONSTANT_TSC) && |
| boot_cpu_data.x86_vendor == X86_VENDOR_AMD && |
| boot_cpu_data.x86 == 16) |
| cpu_khz = calculate_cpu_khz(); |
| |
| if (unsynchronized_tsc()) |
| mark_tsc_unstable("TSCs unsynchronized"); |
| |
| if (cpu_has(&boot_cpu_data, X86_FEATURE_RDTSCP)) |
| vgetcpu_mode = VGETCPU_RDTSCP; |
| else |
| vgetcpu_mode = VGETCPU_LSL; |
| |
| printk(KERN_INFO "time.c: Detected %d.%03d MHz processor.\n", |
| cpu_khz / 1000, cpu_khz % 1000); |
| init_tsc_clocksource(); |
| late_time_init = choose_time_init(); |
| } |