+ unsigned apic, apic_start;
+ unsigned long tsc, tsc_start;
+ int result;
+
+ local_irq_disable();
+
+ /*
+ * Put whatever arbitrary (but long enough) timeout
+ * value into the APIC clock, we just want to get the
+ * counter running for calibration.
+ *
+ * No interrupt enable !
+ */
+ __setup_APIC_LVTT(250000000, 0, 0);
+
+ apic_start = apic_read(APIC_TMCCT);
+#ifdef CONFIG_X86_PM_TIMER
+ if (apic_calibrate_pmtmr && pmtmr_ioport) {
+ pmtimer_wait(5000); /* 5ms wait */
+ apic = apic_read(APIC_TMCCT);
+ result = (apic_start - apic) * 1000L / 5;
+ } else
+#endif
+ {
+ rdtscll(tsc_start);
+
+ do {
+ apic = apic_read(APIC_TMCCT);
+ rdtscll(tsc);
+ } while ((tsc - tsc_start) < TICK_COUNT &&
+ (apic_start - apic) < TICK_COUNT);
+
+ result = (apic_start - apic) * 1000L * tsc_khz /
+ (tsc - tsc_start);
+ }
+
+ local_irq_enable();
+
+ printk(KERN_DEBUG "APIC timer calibration result %d\n", result);
+
+ printk(KERN_INFO "Detected %d.%03d MHz APIC timer.\n",
+ result / 1000 / 1000, result / 1000 % 1000);
+
+ /* Calculate the scaled math multiplication factor */
+ lapic_clockevent.mult = div_sc(result, NSEC_PER_SEC, 32);
+ lapic_clockevent.max_delta_ns =
+ clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
+ lapic_clockevent.min_delta_ns =
+ clockevent_delta2ns(0xF, &lapic_clockevent);
+
+ calibration_result = result / HZ;
+}
+
+/*
+ * Setup the boot APIC
+ *
+ * Calibrate and verify the result.
+ */
+void __init setup_boot_APIC_clock(void)
+{
+ /*
+ * The local apic timer can be disabled via the kernel commandline.
+ * Register the lapic timer as a dummy clock event source on SMP
+ * systems, so the broadcast mechanism is used. On UP systems simply
+ * ignore it.
+ */
+ if (disable_apic_timer) {
+ printk(KERN_INFO "Disabling APIC timer\n");
+ /* No broadcast on UP ! */
+ if (num_possible_cpus() > 1) {
+ lapic_clockevent.mult = 1;
+ setup_APIC_timer();
+ }
+ return;
+ }
+
+ printk(KERN_INFO "Using local APIC timer interrupts.\n");
+ calibrate_APIC_clock();
+
+ /*
+ * Do a sanity check on the APIC calibration result
+ */
+ if (calibration_result < (1000000 / HZ)) {
+ printk(KERN_WARNING
+ "APIC frequency too slow, disabling apic timer\n");
+ /* No broadcast on UP ! */
+ if (num_possible_cpus() > 1)
+ setup_APIC_timer();
+ return;
+ }
+
+ /*
+ * If nmi_watchdog is set to IO_APIC, we need the
+ * PIT/HPET going. Otherwise register lapic as a dummy
+ * device.
+ */
+ if (nmi_watchdog != NMI_IO_APIC)
+ lapic_clockevent.features &= ~CLOCK_EVT_FEAT_DUMMY;
+ else
+ printk(KERN_WARNING "APIC timer registered as dummy,"
+ " due to nmi_watchdog=1!\n");
+
+ setup_APIC_timer();
+}
+
+/*
+ * AMD C1E enabled CPUs have a real nasty problem: Some BIOSes set the
+ * C1E flag only in the secondary CPU, so when we detect the wreckage
+ * we already have enabled the boot CPU local apic timer. Check, if
+ * disable_apic_timer is set and the DUMMY flag is cleared. If yes,
+ * set the DUMMY flag again and force the broadcast mode in the
+ * clockevents layer.
+ */
+void __cpuinit check_boot_apic_timer_broadcast(void)
+{
+ if (!disable_apic_timer ||
+ (lapic_clockevent.features & CLOCK_EVT_FEAT_DUMMY))
+ return;
+
+ printk(KERN_INFO "AMD C1E detected late. Force timer broadcast.\n");
+ lapic_clockevent.features |= CLOCK_EVT_FEAT_DUMMY;
+
+ local_irq_enable();
+ clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_FORCE, &boot_cpu_id);
+ local_irq_disable();
+}
+
+void __cpuinit setup_secondary_APIC_clock(void)
+{
+ check_boot_apic_timer_broadcast();
+ setup_APIC_timer();
+}
+
+/*
+ * The guts of the apic timer interrupt
+ */
+static void local_apic_timer_interrupt(void)
+{
+ int cpu = smp_processor_id();
+ struct clock_event_device *evt = &per_cpu(lapic_events, cpu);
+
+ /*
+ * Normally we should not be here till LAPIC has been initialized but
+ * in some cases like kdump, its possible that there is a pending LAPIC
+ * timer interrupt from previous kernel's context and is delivered in
+ * new kernel the moment interrupts are enabled.
+ *
+ * Interrupts are enabled early and LAPIC is setup much later, hence
+ * its possible that when we get here evt->event_handler is NULL.
+ * Check for event_handler being NULL and discard the interrupt as
+ * spurious.
+ */
+ if (!evt->event_handler) {
+ printk(KERN_WARNING
+ "Spurious LAPIC timer interrupt on cpu %d\n", cpu);
+ /* Switch it off */
+ lapic_timer_setup(CLOCK_EVT_MODE_SHUTDOWN, evt);
+ return;
+ }
+
+ /*
+ * the NMI deadlock-detector uses this.
+ */
+ add_pda(apic_timer_irqs, 1);
+
+ evt->event_handler(evt);
+}
+
+/*
+ * Local APIC timer interrupt. This is the most natural way for doing
+ * local interrupts, but local timer interrupts can be emulated by
+ * broadcast interrupts too. [in case the hw doesn't support APIC timers]
+ *
+ * [ if a single-CPU system runs an SMP kernel then we call the local
+ * interrupt as well. Thus we cannot inline the local irq ... ]
+ */
+void smp_apic_timer_interrupt(struct pt_regs *regs)
+{
+ struct pt_regs *old_regs = set_irq_regs(regs);
+
+ /*
+ * NOTE! We'd better ACK the irq immediately,
+ * because timer handling can be slow.
+ */
+ ack_APIC_irq();
+ /*
+ * update_process_times() expects us to have done irq_enter().
+ * Besides, if we don't timer interrupts ignore the global
+ * interrupt lock, which is the WrongThing (tm) to do.
+ */
+ exit_idle();
+ irq_enter();
+ local_apic_timer_interrupt();
+ irq_exit();
+ set_irq_regs(old_regs);
+}
+
+int setup_profiling_timer(unsigned int multiplier)
+{
+ return -EINVAL;
+}
+
+
+/*
+ * Local APIC start and shutdown
+ */
+
+/**
+ * clear_local_APIC - shutdown the local APIC
+ *
+ * This is called, when a CPU is disabled and before rebooting, so the state of
+ * the local APIC has no dangling leftovers. Also used to cleanout any BIOS
+ * leftovers during boot.
+ */
+void clear_local_APIC(void)
+{
+ int maxlvt = lapic_get_maxlvt();
+ u32 v;
+
+ /* APIC hasn't been mapped yet */
+ if (!apic_phys)
+ return;
+
+ maxlvt = lapic_get_maxlvt();
+ /*
+ * Masking an LVT entry can trigger a local APIC error
+ * if the vector is zero. Mask LVTERR first to prevent this.
+ */
+ if (maxlvt >= 3) {
+ v = ERROR_APIC_VECTOR; /* any non-zero vector will do */
+ apic_write(APIC_LVTERR, v | APIC_LVT_MASKED);
+ }
+ /*
+ * Careful: we have to set masks only first to deassert
+ * any level-triggered sources.
+ */
+ v = apic_read(APIC_LVTT);
+ apic_write(APIC_LVTT, v | APIC_LVT_MASKED);
+ v = apic_read(APIC_LVT0);
+ apic_write(APIC_LVT0, v | APIC_LVT_MASKED);
+ v = apic_read(APIC_LVT1);
+ apic_write(APIC_LVT1, v | APIC_LVT_MASKED);
+ if (maxlvt >= 4) {
+ v = apic_read(APIC_LVTPC);
+ apic_write(APIC_LVTPC, v | APIC_LVT_MASKED);
+ }
+
+ /*
+ * Clean APIC state for other OSs:
+ */
+ apic_write(APIC_LVTT, APIC_LVT_MASKED);
+ apic_write(APIC_LVT0, APIC_LVT_MASKED);
+ apic_write(APIC_LVT1, APIC_LVT_MASKED);
+ if (maxlvt >= 3)
+ apic_write(APIC_LVTERR, APIC_LVT_MASKED);
+ if (maxlvt >= 4)
+ apic_write(APIC_LVTPC, APIC_LVT_MASKED);
+ apic_write(APIC_ESR, 0);
+ apic_read(APIC_ESR);
+}
+
+/**
+ * disable_local_APIC - clear and disable the local APIC
+ */
+void disable_local_APIC(void)
+{
+ unsigned int value;
+
+ clear_local_APIC();
+
+ /*
+ * Disable APIC (implies clearing of registers
+ * for 82489DX!).
+ */
+ value = apic_read(APIC_SPIV);
+ value &= ~APIC_SPIV_APIC_ENABLED;
+ apic_write(APIC_SPIV, value);
+}
+
+void lapic_shutdown(void)
+{
+ unsigned long flags;
+
+ if (!cpu_has_apic)
+ return;
+
+ local_irq_save(flags);
+
+ disable_local_APIC();
+
+ local_irq_restore(flags);
+}
+
+/*
+ * This is to verify that we're looking at a real local APIC.
+ * Check these against your board if the CPUs aren't getting
+ * started for no apparent reason.
+ */
+int __init verify_local_APIC(void)
+{
+ unsigned int reg0, reg1;