2 * Local APIC handling, local APIC timers
4 * (c) 1999, 2000 Ingo Molnar <mingo@redhat.com>
7 * Maciej W. Rozycki : Bits for genuine 82489DX APICs;
8 * thanks to Eric Gilmore
10 * for testing these extensively.
11 * Maciej W. Rozycki : Various updates and fixes.
12 * Mikael Pettersson : Power Management for UP-APIC.
14 * Mikael Pettersson : PM converted to driver model.
17 #include <linux/init.h>
20 #include <linux/delay.h>
21 #include <linux/bootmem.h>
22 #include <linux/interrupt.h>
23 #include <linux/mc146818rtc.h>
24 #include <linux/kernel_stat.h>
25 #include <linux/sysdev.h>
26 #include <linux/module.h>
27 #include <linux/ioport.h>
28 #include <linux/clockchips.h>
30 #include <asm/atomic.h>
33 #include <asm/mpspec.h>
34 #include <asm/pgalloc.h>
35 #include <asm/mach_apic.h>
38 #include <asm/proto.h>
39 #include <asm/timex.h>
44 int disable_apic_timer __cpuinitdata;
45 static int apic_calibrate_pmtmr __initdata;
47 /* Local APIC timer works in C2? */
48 int local_apic_timer_c2_ok;
49 EXPORT_SYMBOL_GPL(local_apic_timer_c2_ok);
51 static struct resource *ioapic_resources;
52 static struct resource lapic_resource = {
54 .flags = IORESOURCE_MEM | IORESOURCE_BUSY,
57 static unsigned int calibration_result;
59 static int lapic_next_event(unsigned long delta,
60 struct clock_event_device *evt);
61 static void lapic_timer_setup(enum clock_event_mode mode,
62 struct clock_event_device *evt);
64 static void lapic_timer_broadcast(cpumask_t mask);
66 static void __setup_APIC_LVTT(unsigned int clocks, int oneshot, int irqen);
68 static struct clock_event_device lapic_clockevent = {
70 .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT
71 | CLOCK_EVT_FEAT_C3STOP | CLOCK_EVT_FEAT_DUMMY,
73 .set_mode = lapic_timer_setup,
74 .set_next_event = lapic_next_event,
75 .broadcast = lapic_timer_broadcast,
79 static DEFINE_PER_CPU(struct clock_event_device, lapic_events);
81 static int lapic_next_event(unsigned long delta,
82 struct clock_event_device *evt)
84 apic_write(APIC_TMICT, delta);
88 static void lapic_timer_setup(enum clock_event_mode mode,
89 struct clock_event_device *evt)
94 /* Lapic used as dummy for broadcast ? */
95 if (evt->features & CLOCK_EVT_FEAT_DUMMY)
98 local_irq_save(flags);
101 case CLOCK_EVT_MODE_PERIODIC:
102 case CLOCK_EVT_MODE_ONESHOT:
103 __setup_APIC_LVTT(calibration_result,
104 mode != CLOCK_EVT_MODE_PERIODIC, 1);
106 case CLOCK_EVT_MODE_UNUSED:
107 case CLOCK_EVT_MODE_SHUTDOWN:
108 v = apic_read(APIC_LVTT);
109 v |= (APIC_LVT_MASKED | LOCAL_TIMER_VECTOR);
110 apic_write(APIC_LVTT, v);
112 case CLOCK_EVT_MODE_RESUME:
113 /* Nothing to do here */
117 local_irq_restore(flags);
121 * Local APIC timer broadcast function
123 static void lapic_timer_broadcast(cpumask_t mask)
126 send_IPI_mask(mask, LOCAL_TIMER_VECTOR);
130 static void apic_pm_activate(void);
132 void apic_wait_icr_idle(void)
134 while (apic_read(APIC_ICR) & APIC_ICR_BUSY)
138 unsigned int safe_apic_wait_icr_idle(void)
140 unsigned int send_status;
145 send_status = apic_read(APIC_ICR) & APIC_ICR_BUSY;
149 } while (timeout++ < 1000);
154 void enable_NMI_through_LVT0 (void * dummy)
158 /* unmask and set to NMI */
160 apic_write(APIC_LVT0, v);
165 unsigned int v, maxlvt;
167 v = apic_read(APIC_LVR);
168 maxlvt = GET_APIC_MAXLVT(v);
173 * 'what should we do if we get a hw irq event on an illegal vector'.
174 * each architecture has to answer this themselves.
176 void ack_bad_irq(unsigned int irq)
178 printk("unexpected IRQ trap at vector %02x\n", irq);
180 * Currently unexpected vectors happen only on SMP and APIC.
181 * We _must_ ack these because every local APIC has only N
182 * irq slots per priority level, and a 'hanging, unacked' IRQ
183 * holds up an irq slot - in excessive cases (when multiple
184 * unexpected vectors occur) that might lock up the APIC
186 * But don't ack when the APIC is disabled. -AK
192 void clear_local_APIC(void)
197 maxlvt = get_maxlvt();
200 * Masking an LVT entry can trigger a local APIC error
201 * if the vector is zero. Mask LVTERR first to prevent this.
204 v = ERROR_APIC_VECTOR; /* any non-zero vector will do */
205 apic_write(APIC_LVTERR, v | APIC_LVT_MASKED);
208 * Careful: we have to set masks only first to deassert
209 * any level-triggered sources.
211 v = apic_read(APIC_LVTT);
212 apic_write(APIC_LVTT, v | APIC_LVT_MASKED);
213 v = apic_read(APIC_LVT0);
214 apic_write(APIC_LVT0, v | APIC_LVT_MASKED);
215 v = apic_read(APIC_LVT1);
216 apic_write(APIC_LVT1, v | APIC_LVT_MASKED);
218 v = apic_read(APIC_LVTPC);
219 apic_write(APIC_LVTPC, v | APIC_LVT_MASKED);
223 * Clean APIC state for other OSs:
225 apic_write(APIC_LVTT, APIC_LVT_MASKED);
226 apic_write(APIC_LVT0, APIC_LVT_MASKED);
227 apic_write(APIC_LVT1, APIC_LVT_MASKED);
229 apic_write(APIC_LVTERR, APIC_LVT_MASKED);
231 apic_write(APIC_LVTPC, APIC_LVT_MASKED);
232 apic_write(APIC_ESR, 0);
236 void disconnect_bsp_APIC(int virt_wire_setup)
238 /* Go back to Virtual Wire compatibility mode */
241 /* For the spurious interrupt use vector F, and enable it */
242 value = apic_read(APIC_SPIV);
243 value &= ~APIC_VECTOR_MASK;
244 value |= APIC_SPIV_APIC_ENABLED;
246 apic_write(APIC_SPIV, value);
248 if (!virt_wire_setup) {
250 * For LVT0 make it edge triggered, active high,
251 * external and enabled
253 value = apic_read(APIC_LVT0);
254 value &= ~(APIC_MODE_MASK | APIC_SEND_PENDING |
255 APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
256 APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED );
257 value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
258 value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_EXTINT);
259 apic_write(APIC_LVT0, value);
262 apic_write(APIC_LVT0, APIC_LVT_MASKED);
265 /* For LVT1 make it edge triggered, active high, nmi and enabled */
266 value = apic_read(APIC_LVT1);
267 value &= ~(APIC_MODE_MASK | APIC_SEND_PENDING |
268 APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
269 APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED);
270 value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
271 value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_NMI);
272 apic_write(APIC_LVT1, value);
275 void disable_local_APIC(void)
282 * Disable APIC (implies clearing of registers
285 value = apic_read(APIC_SPIV);
286 value &= ~APIC_SPIV_APIC_ENABLED;
287 apic_write(APIC_SPIV, value);
291 * This is to verify that we're looking at a real local APIC.
292 * Check these against your board if the CPUs aren't getting
293 * started for no apparent reason.
295 int __init verify_local_APIC(void)
297 unsigned int reg0, reg1;
300 * The version register is read-only in a real APIC.
302 reg0 = apic_read(APIC_LVR);
303 apic_printk(APIC_DEBUG, "Getting VERSION: %x\n", reg0);
304 apic_write(APIC_LVR, reg0 ^ APIC_LVR_MASK);
305 reg1 = apic_read(APIC_LVR);
306 apic_printk(APIC_DEBUG, "Getting VERSION: %x\n", reg1);
309 * The two version reads above should print the same
310 * numbers. If the second one is different, then we
311 * poke at a non-APIC.
317 * Check if the version looks reasonably.
319 reg1 = GET_APIC_VERSION(reg0);
320 if (reg1 == 0x00 || reg1 == 0xff)
323 if (reg1 < 0x02 || reg1 == 0xff)
327 * The ID register is read/write in a real APIC.
329 reg0 = apic_read(APIC_ID);
330 apic_printk(APIC_DEBUG, "Getting ID: %x\n", reg0);
331 apic_write(APIC_ID, reg0 ^ APIC_ID_MASK);
332 reg1 = apic_read(APIC_ID);
333 apic_printk(APIC_DEBUG, "Getting ID: %x\n", reg1);
334 apic_write(APIC_ID, reg0);
335 if (reg1 != (reg0 ^ APIC_ID_MASK))
339 * The next two are just to see if we have sane values.
340 * They're only really relevant if we're in Virtual Wire
341 * compatibility mode, but most boxes are anymore.
343 reg0 = apic_read(APIC_LVT0);
344 apic_printk(APIC_DEBUG,"Getting LVT0: %x\n", reg0);
345 reg1 = apic_read(APIC_LVT1);
346 apic_printk(APIC_DEBUG, "Getting LVT1: %x\n", reg1);
351 void __init sync_Arb_IDs(void)
353 /* Unsupported on P4 - see Intel Dev. Manual Vol. 3, Ch. 8.6.1 */
354 unsigned int ver = GET_APIC_VERSION(apic_read(APIC_LVR));
355 if (ver >= 0x14) /* P4 or higher */
361 apic_wait_icr_idle();
363 apic_printk(APIC_DEBUG, "Synchronizing Arb IDs.\n");
364 apic_write(APIC_ICR, APIC_DEST_ALLINC | APIC_INT_LEVELTRIG
369 * An initial setup of the virtual wire mode.
371 void __init init_bsp_APIC(void)
376 * Don't do the setup now if we have a SMP BIOS as the
377 * through-I/O-APIC virtual wire mode might be active.
379 if (smp_found_config || !cpu_has_apic)
382 value = apic_read(APIC_LVR);
385 * Do not trust the local APIC being empty at bootup.
392 value = apic_read(APIC_SPIV);
393 value &= ~APIC_VECTOR_MASK;
394 value |= APIC_SPIV_APIC_ENABLED;
395 value |= APIC_SPIV_FOCUS_DISABLED;
396 value |= SPURIOUS_APIC_VECTOR;
397 apic_write(APIC_SPIV, value);
400 * Set up the virtual wire mode.
402 apic_write(APIC_LVT0, APIC_DM_EXTINT);
404 apic_write(APIC_LVT1, value);
407 void __cpuinit setup_local_APIC (void)
409 unsigned int value, maxlvt;
412 value = apic_read(APIC_LVR);
414 BUILD_BUG_ON((SPURIOUS_APIC_VECTOR & 0x0f) != 0x0f);
417 * Double-check whether this APIC is really registered.
418 * This is meaningless in clustered apic mode, so we skip it.
420 if (!apic_id_registered())
424 * Intel recommends to set DFR, LDR and TPR before enabling
425 * an APIC. See e.g. "AP-388 82489DX User's Manual" (Intel
426 * document number 292116). So here it goes...
431 * Set Task Priority to 'accept all'. We never change this
434 value = apic_read(APIC_TASKPRI);
435 value &= ~APIC_TPRI_MASK;
436 apic_write(APIC_TASKPRI, value);
439 * After a crash, we no longer service the interrupts and a pending
440 * interrupt from previous kernel might still have ISR bit set.
442 * Most probably by now CPU has serviced that pending interrupt and
443 * it might not have done the ack_APIC_irq() because it thought,
444 * interrupt came from i8259 as ExtInt. LAPIC did not get EOI so it
445 * does not clear the ISR bit and cpu thinks it has already serivced
446 * the interrupt. Hence a vector might get locked. It was noticed
447 * for timer irq (vector 0x31). Issue an extra EOI to clear ISR.
449 for (i = APIC_ISR_NR - 1; i >= 0; i--) {
450 value = apic_read(APIC_ISR + i*0x10);
451 for (j = 31; j >= 0; j--) {
458 * Now that we are all set up, enable the APIC
460 value = apic_read(APIC_SPIV);
461 value &= ~APIC_VECTOR_MASK;
465 value |= APIC_SPIV_APIC_ENABLED;
467 /* We always use processor focus */
470 * Set spurious IRQ vector
472 value |= SPURIOUS_APIC_VECTOR;
473 apic_write(APIC_SPIV, value);
478 * set up through-local-APIC on the BP's LINT0. This is not
479 * strictly necessary in pure symmetric-IO mode, but sometimes
480 * we delegate interrupts to the 8259A.
483 * TODO: set up through-local-APIC from through-I/O-APIC? --macro
485 value = apic_read(APIC_LVT0) & APIC_LVT_MASKED;
486 if (!smp_processor_id() && !value) {
487 value = APIC_DM_EXTINT;
488 apic_printk(APIC_VERBOSE, "enabled ExtINT on CPU#%d\n",
491 value = APIC_DM_EXTINT | APIC_LVT_MASKED;
492 apic_printk(APIC_VERBOSE, "masked ExtINT on CPU#%d\n",
495 apic_write(APIC_LVT0, value);
498 * only the BP should see the LINT1 NMI signal, obviously.
500 if (!smp_processor_id())
503 value = APIC_DM_NMI | APIC_LVT_MASKED;
504 apic_write(APIC_LVT1, value);
508 maxlvt = get_maxlvt();
509 oldvalue = apic_read(APIC_ESR);
510 value = ERROR_APIC_VECTOR; // enables sending errors
511 apic_write(APIC_LVTERR, value);
513 * spec says clear errors after enabling vector.
516 apic_write(APIC_ESR, 0);
517 value = apic_read(APIC_ESR);
518 if (value != oldvalue)
519 apic_printk(APIC_VERBOSE,
520 "ESR value after enabling vector: %08x, after %08x\n",
524 nmi_watchdog_default();
525 setup_apic_nmi_watchdog(NULL);
532 /* 'active' is true if the local APIC was enabled by us and
533 not the BIOS; this signifies that we are also responsible
534 for disabling it before entering apm/acpi suspend */
536 /* r/w apic fields */
537 unsigned int apic_id;
538 unsigned int apic_taskpri;
539 unsigned int apic_ldr;
540 unsigned int apic_dfr;
541 unsigned int apic_spiv;
542 unsigned int apic_lvtt;
543 unsigned int apic_lvtpc;
544 unsigned int apic_lvt0;
545 unsigned int apic_lvt1;
546 unsigned int apic_lvterr;
547 unsigned int apic_tmict;
548 unsigned int apic_tdcr;
549 unsigned int apic_thmr;
552 static int lapic_suspend(struct sys_device *dev, pm_message_t state)
557 if (!apic_pm_state.active)
560 maxlvt = get_maxlvt();
562 apic_pm_state.apic_id = apic_read(APIC_ID);
563 apic_pm_state.apic_taskpri = apic_read(APIC_TASKPRI);
564 apic_pm_state.apic_ldr = apic_read(APIC_LDR);
565 apic_pm_state.apic_dfr = apic_read(APIC_DFR);
566 apic_pm_state.apic_spiv = apic_read(APIC_SPIV);
567 apic_pm_state.apic_lvtt = apic_read(APIC_LVTT);
569 apic_pm_state.apic_lvtpc = apic_read(APIC_LVTPC);
570 apic_pm_state.apic_lvt0 = apic_read(APIC_LVT0);
571 apic_pm_state.apic_lvt1 = apic_read(APIC_LVT1);
572 apic_pm_state.apic_lvterr = apic_read(APIC_LVTERR);
573 apic_pm_state.apic_tmict = apic_read(APIC_TMICT);
574 apic_pm_state.apic_tdcr = apic_read(APIC_TDCR);
575 #ifdef CONFIG_X86_MCE_INTEL
577 apic_pm_state.apic_thmr = apic_read(APIC_LVTTHMR);
579 local_irq_save(flags);
580 disable_local_APIC();
581 local_irq_restore(flags);
585 static int lapic_resume(struct sys_device *dev)
591 if (!apic_pm_state.active)
594 maxlvt = get_maxlvt();
596 local_irq_save(flags);
597 rdmsr(MSR_IA32_APICBASE, l, h);
598 l &= ~MSR_IA32_APICBASE_BASE;
599 l |= MSR_IA32_APICBASE_ENABLE | mp_lapic_addr;
600 wrmsr(MSR_IA32_APICBASE, l, h);
601 apic_write(APIC_LVTERR, ERROR_APIC_VECTOR | APIC_LVT_MASKED);
602 apic_write(APIC_ID, apic_pm_state.apic_id);
603 apic_write(APIC_DFR, apic_pm_state.apic_dfr);
604 apic_write(APIC_LDR, apic_pm_state.apic_ldr);
605 apic_write(APIC_TASKPRI, apic_pm_state.apic_taskpri);
606 apic_write(APIC_SPIV, apic_pm_state.apic_spiv);
607 apic_write(APIC_LVT0, apic_pm_state.apic_lvt0);
608 apic_write(APIC_LVT1, apic_pm_state.apic_lvt1);
609 #ifdef CONFIG_X86_MCE_INTEL
611 apic_write(APIC_LVTTHMR, apic_pm_state.apic_thmr);
614 apic_write(APIC_LVTPC, apic_pm_state.apic_lvtpc);
615 apic_write(APIC_LVTT, apic_pm_state.apic_lvtt);
616 apic_write(APIC_TDCR, apic_pm_state.apic_tdcr);
617 apic_write(APIC_TMICT, apic_pm_state.apic_tmict);
618 apic_write(APIC_ESR, 0);
620 apic_write(APIC_LVTERR, apic_pm_state.apic_lvterr);
621 apic_write(APIC_ESR, 0);
623 local_irq_restore(flags);
627 static struct sysdev_class lapic_sysclass = {
628 set_kset_name("lapic"),
629 .resume = lapic_resume,
630 .suspend = lapic_suspend,
633 static struct sys_device device_lapic = {
635 .cls = &lapic_sysclass,
638 static void __cpuinit apic_pm_activate(void)
640 apic_pm_state.active = 1;
643 static int __init init_lapic_sysfs(void)
648 /* XXX: remove suspend/resume procs if !apic_pm_state.active? */
649 error = sysdev_class_register(&lapic_sysclass);
651 error = sysdev_register(&device_lapic);
654 device_initcall(init_lapic_sysfs);
656 #else /* CONFIG_PM */
658 static void apic_pm_activate(void) { }
660 #endif /* CONFIG_PM */
662 static int __init apic_set_verbosity(char *str)
665 skip_ioapic_setup = 0;
669 if (strcmp("debug", str) == 0)
670 apic_verbosity = APIC_DEBUG;
671 else if (strcmp("verbose", str) == 0)
672 apic_verbosity = APIC_VERBOSE;
674 printk(KERN_WARNING "APIC Verbosity level %s not recognised"
675 " use apic=verbose or apic=debug\n", str);
681 early_param("apic", apic_set_verbosity);
684 * Detect and enable local APICs on non-SMP boards.
685 * Original code written by Keir Fraser.
686 * On AMD64 we trust the BIOS - if it says no APIC it is likely
687 * not correctly set up (usually the APIC timer won't work etc.)
690 static int __init detect_init_APIC (void)
693 printk(KERN_INFO "No local APIC present\n");
697 mp_lapic_addr = APIC_DEFAULT_PHYS_BASE;
702 #ifdef CONFIG_X86_IO_APIC
703 static struct resource * __init ioapic_setup_resources(void)
705 #define IOAPIC_RESOURCE_NAME_SIZE 11
707 struct resource *res;
714 n = IOAPIC_RESOURCE_NAME_SIZE + sizeof(struct resource);
717 mem = alloc_bootmem(n);
722 mem += sizeof(struct resource) * nr_ioapics;
724 for (i = 0; i < nr_ioapics; i++) {
726 res[i].flags = IORESOURCE_MEM | IORESOURCE_BUSY;
727 sprintf(mem, "IOAPIC %u", i);
728 mem += IOAPIC_RESOURCE_NAME_SIZE;
732 ioapic_resources = res;
737 static int __init ioapic_insert_resources(void)
740 struct resource *r = ioapic_resources;
743 printk("IO APIC resources could be not be allocated.\n");
747 for (i = 0; i < nr_ioapics; i++) {
748 insert_resource(&iomem_resource, r);
755 /* Insert the IO APIC resources after PCI initialization has occured to handle
756 * IO APICS that are mapped in on a BAR in PCI space. */
757 late_initcall(ioapic_insert_resources);
760 void __init init_apic_mappings(void)
762 unsigned long apic_phys;
765 * If no local APIC can be found then set up a fake all
766 * zeroes page to simulate the local APIC and another
767 * one for the IO-APIC.
769 if (!smp_found_config && detect_init_APIC()) {
770 apic_phys = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
771 apic_phys = __pa(apic_phys);
773 apic_phys = mp_lapic_addr;
775 set_fixmap_nocache(FIX_APIC_BASE, apic_phys);
776 apic_printk(APIC_VERBOSE, "mapped APIC to %16lx (%16lx)\n",
777 APIC_BASE, apic_phys);
779 /* Put local APIC into the resource map. */
780 lapic_resource.start = apic_phys;
781 lapic_resource.end = lapic_resource.start + PAGE_SIZE - 1;
782 insert_resource(&iomem_resource, &lapic_resource);
785 * Fetch the APIC ID of the BSP in case we have a
786 * default configuration (or the MP table is broken).
788 boot_cpu_id = GET_APIC_ID(apic_read(APIC_ID));
791 unsigned long ioapic_phys, idx = FIX_IO_APIC_BASE_0;
793 struct resource *ioapic_res;
795 ioapic_res = ioapic_setup_resources();
796 for (i = 0; i < nr_ioapics; i++) {
797 if (smp_found_config) {
798 ioapic_phys = mp_ioapics[i].mpc_apicaddr;
800 ioapic_phys = (unsigned long)
801 alloc_bootmem_pages(PAGE_SIZE);
802 ioapic_phys = __pa(ioapic_phys);
804 set_fixmap_nocache(idx, ioapic_phys);
805 apic_printk(APIC_VERBOSE,
806 "mapped IOAPIC to %016lx (%016lx)\n",
807 __fix_to_virt(idx), ioapic_phys);
810 if (ioapic_res != NULL) {
811 ioapic_res->start = ioapic_phys;
812 ioapic_res->end = ioapic_phys + (4 * 1024) - 1;
820 * This function sets up the local APIC timer, with a timeout of
821 * 'clocks' APIC bus clock. During calibration we actually call
822 * this function twice on the boot CPU, once with a bogus timeout
823 * value, second time for real. The other (noncalibrating) CPUs
824 * call this function only once, with the real, calibrated value.
826 * We do reads before writes even if unnecessary, to get around the
827 * P5 APIC double write bug.
830 static void __setup_APIC_LVTT(unsigned int clocks, int oneshot, int irqen)
832 unsigned int lvtt_value, tmp_value;
834 lvtt_value = LOCAL_TIMER_VECTOR;
836 lvtt_value |= APIC_LVT_TIMER_PERIODIC;
838 lvtt_value |= APIC_LVT_MASKED;
840 apic_write(APIC_LVTT, lvtt_value);
845 tmp_value = apic_read(APIC_TDCR);
846 apic_write(APIC_TDCR, (tmp_value
847 & ~(APIC_TDR_DIV_1 | APIC_TDR_DIV_TMBASE))
851 apic_write(APIC_TMICT, clocks);
854 static void setup_APIC_timer(void)
856 struct clock_event_device *levt = &__get_cpu_var(lapic_events);
858 memcpy(levt, &lapic_clockevent, sizeof(*levt));
859 levt->cpumask = cpumask_of_cpu(smp_processor_id());
861 clockevents_register_device(levt);
865 * In this function we calibrate APIC bus clocks to the external
866 * timer. Unfortunately we cannot use jiffies and the timer irq
867 * to calibrate, since some later bootup code depends on getting
868 * the first irq? Ugh.
870 * We want to do the calibration only once since we
871 * want to have local timer irqs syncron. CPUs connected
872 * by the same APIC bus have the very same bus frequency.
873 * And we want to have irqs off anyways, no accidental
877 #define TICK_COUNT 100000000
879 static void __init calibrate_APIC_clock(void)
881 unsigned apic, apic_start;
882 unsigned long tsc, tsc_start;
888 * Put whatever arbitrary (but long enough) timeout
889 * value into the APIC clock, we just want to get the
890 * counter running for calibration.
892 * No interrupt enable !
894 __setup_APIC_LVTT(250000000, 0, 0);
896 apic_start = apic_read(APIC_TMCCT);
897 #ifdef CONFIG_X86_PM_TIMER
898 if (apic_calibrate_pmtmr && pmtmr_ioport) {
899 pmtimer_wait(5000); /* 5ms wait */
900 apic = apic_read(APIC_TMCCT);
901 result = (apic_start - apic) * 1000L / 5;
908 apic = apic_read(APIC_TMCCT);
910 } while ((tsc - tsc_start) < TICK_COUNT &&
911 (apic_start - apic) < TICK_COUNT);
913 result = (apic_start - apic) * 1000L * tsc_khz /
919 printk(KERN_DEBUG "APIC timer calibration result %d\n", result);
921 printk(KERN_INFO "Detected %d.%03d MHz APIC timer.\n",
922 result / 1000 / 1000, result / 1000 % 1000);
924 /* Calculate the scaled math multiplication factor */
925 lapic_clockevent.mult = div_sc(result, NSEC_PER_SEC, 32);
926 lapic_clockevent.max_delta_ns =
927 clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
928 lapic_clockevent.min_delta_ns =
929 clockevent_delta2ns(0xF, &lapic_clockevent);
931 calibration_result = result / HZ;
934 void __init setup_boot_APIC_clock (void)
937 * The local apic timer can be disabled via the kernel commandline.
938 * Register the lapic timer as a dummy clock event source on SMP
939 * systems, so the broadcast mechanism is used. On UP systems simply
942 if (disable_apic_timer) {
943 printk(KERN_INFO "Disabling APIC timer\n");
944 /* No broadcast on UP ! */
945 if (num_possible_cpus() > 1)
950 printk(KERN_INFO "Using local APIC timer interrupts.\n");
951 calibrate_APIC_clock();
954 * If nmi_watchdog is set to IO_APIC, we need the
955 * PIT/HPET going. Otherwise register lapic as a dummy
958 if (nmi_watchdog != NMI_IO_APIC)
959 lapic_clockevent.features &= ~CLOCK_EVT_FEAT_DUMMY;
961 printk(KERN_WARNING "APIC timer registered as dummy,"
962 " due to nmi_watchdog=1!\n");
968 * AMD C1E enabled CPUs have a real nasty problem: Some BIOSes set the
969 * C1E flag only in the secondary CPU, so when we detect the wreckage
970 * we already have enabled the boot CPU local apic timer. Check, if
971 * disable_apic_timer is set and the DUMMY flag is cleared. If yes,
972 * set the DUMMY flag again and force the broadcast mode in the
975 void __cpuinit check_boot_apic_timer_broadcast(void)
977 struct clock_event_device *levt = &per_cpu(lapic_events, boot_cpu_id);
979 if (!disable_apic_timer ||
980 (lapic_clockevent.features & CLOCK_EVT_FEAT_DUMMY))
983 printk(KERN_INFO "AMD C1E detected late. Force timer broadcast.\n");
984 lapic_clockevent.features |= CLOCK_EVT_FEAT_DUMMY;
985 levt->features |= CLOCK_EVT_FEAT_DUMMY;
988 clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_FORCE, &boot_cpu_id);
992 void __cpuinit setup_secondary_APIC_clock(void)
994 check_boot_apic_timer_broadcast();
998 int setup_profiling_timer(unsigned int multiplier)
1003 void setup_APIC_extended_lvt(unsigned char lvt_off, unsigned char vector,
1004 unsigned char msg_type, unsigned char mask)
1006 unsigned long reg = (lvt_off << 4) + K8_APIC_EXT_LVT_BASE;
1007 unsigned int v = (mask << 16) | (msg_type << 8) | vector;
1012 * Local timer interrupt handler. It does both profiling and
1013 * process statistics/rescheduling.
1015 * We do profiling in every local tick, statistics/rescheduling
1016 * happen only every 'profiling multiplier' ticks. The default
1017 * multiplier is 1 and it can be changed by writing the new multiplier
1018 * value into /proc/profile.
1021 void smp_local_timer_interrupt(void)
1023 int cpu = smp_processor_id();
1024 struct clock_event_device *evt = &per_cpu(lapic_events, cpu);
1027 * Normally we should not be here till LAPIC has been initialized but
1028 * in some cases like kdump, its possible that there is a pending LAPIC
1029 * timer interrupt from previous kernel's context and is delivered in
1030 * new kernel the moment interrupts are enabled.
1032 * Interrupts are enabled early and LAPIC is setup much later, hence
1033 * its possible that when we get here evt->event_handler is NULL.
1034 * Check for event_handler being NULL and discard the interrupt as
1037 if (!evt->event_handler) {
1039 "Spurious LAPIC timer interrupt on cpu %d\n", cpu);
1041 lapic_timer_setup(CLOCK_EVT_MODE_SHUTDOWN, evt);
1046 * the NMI deadlock-detector uses this.
1048 add_pda(apic_timer_irqs, 1);
1050 evt->event_handler(evt);
1054 * Local APIC timer interrupt. This is the most natural way for doing
1055 * local interrupts, but local timer interrupts can be emulated by
1056 * broadcast interrupts too. [in case the hw doesn't support APIC timers]
1058 * [ if a single-CPU system runs an SMP kernel then we call the local
1059 * interrupt as well. Thus we cannot inline the local irq ... ]
1061 void smp_apic_timer_interrupt(struct pt_regs *regs)
1063 struct pt_regs *old_regs = set_irq_regs(regs);
1066 * NOTE! We'd better ACK the irq immediately,
1067 * because timer handling can be slow.
1071 * update_process_times() expects us to have done irq_enter().
1072 * Besides, if we don't timer interrupts ignore the global
1073 * interrupt lock, which is the WrongThing (tm) to do.
1077 smp_local_timer_interrupt();
1079 set_irq_regs(old_regs);
1083 * apic_is_clustered_box() -- Check if we can expect good TSC
1085 * Thus far, the major user of this is IBM's Summit2 series:
1087 * Clustered boxes may have unsynced TSC problems if they are
1088 * multi-chassis. Use available data to take a good guess.
1089 * If in doubt, go HPET.
1091 __cpuinit int apic_is_clustered_box(void)
1093 int i, clusters, zeros;
1095 DECLARE_BITMAP(clustermap, NUM_APIC_CLUSTERS);
1097 bitmap_zero(clustermap, NUM_APIC_CLUSTERS);
1099 for (i = 0; i < NR_CPUS; i++) {
1100 id = bios_cpu_apicid[i];
1101 if (id != BAD_APICID)
1102 __set_bit(APIC_CLUSTERID(id), clustermap);
1105 /* Problem: Partially populated chassis may not have CPUs in some of
1106 * the APIC clusters they have been allocated. Only present CPUs have
1107 * bios_cpu_apicid entries, thus causing zeroes in the bitmap. Since
1108 * clusters are allocated sequentially, count zeros only if they are
1113 for (i = 0; i < NUM_APIC_CLUSTERS; i++) {
1114 if (test_bit(i, clustermap)) {
1115 clusters += 1 + zeros;
1122 * If clusters > 2, then should be multi-chassis.
1123 * May have to revisit this when multi-core + hyperthreaded CPUs come
1124 * out, but AFAIK this will work even for them.
1126 return (clusters > 2);
1130 * This interrupt should _never_ happen with our APIC/SMP architecture
1132 asmlinkage void smp_spurious_interrupt(void)
1138 * Check if this really is a spurious interrupt and ACK it
1139 * if it is a vectored one. Just in case...
1140 * Spurious interrupts should not be ACKed.
1142 v = apic_read(APIC_ISR + ((SPURIOUS_APIC_VECTOR & ~0x1f) >> 1));
1143 if (v & (1 << (SPURIOUS_APIC_VECTOR & 0x1f)))
1150 * This interrupt should never happen with our APIC/SMP architecture
1153 asmlinkage void smp_error_interrupt(void)
1159 /* First tickle the hardware, only then report what went on. -- REW */
1160 v = apic_read(APIC_ESR);
1161 apic_write(APIC_ESR, 0);
1162 v1 = apic_read(APIC_ESR);
1164 atomic_inc(&irq_err_count);
1166 /* Here is what the APIC error bits mean:
1169 2: Send accept error
1170 3: Receive accept error
1172 5: Send illegal vector
1173 6: Received illegal vector
1174 7: Illegal register address
1176 printk (KERN_DEBUG "APIC error on CPU%d: %02x(%02x)\n",
1177 smp_processor_id(), v , v1);
1184 * This initializes the IO-APIC and APIC hardware if this is
1187 int __init APIC_init_uniprocessor (void)
1190 printk(KERN_INFO "Apic disabled\n");
1193 if (!cpu_has_apic) {
1195 printk(KERN_INFO "Apic disabled by BIOS\n");
1199 verify_local_APIC();
1201 phys_cpu_present_map = physid_mask_of_physid(boot_cpu_id);
1202 apic_write(APIC_ID, SET_APIC_ID(boot_cpu_id));
1206 if (smp_found_config && !skip_ioapic_setup && nr_ioapics)
1210 setup_boot_APIC_clock();
1211 check_nmi_watchdog();
1215 static __init int setup_disableapic(char *str)
1218 clear_bit(X86_FEATURE_APIC, boot_cpu_data.x86_capability);
1221 early_param("disableapic", setup_disableapic);
1223 /* same as disableapic, for compatibility */
1224 static __init int setup_nolapic(char *str)
1226 return setup_disableapic(str);
1228 early_param("nolapic", setup_nolapic);
1230 static int __init parse_lapic_timer_c2_ok(char *arg)
1232 local_apic_timer_c2_ok = 1;
1235 early_param("lapic_timer_c2_ok", parse_lapic_timer_c2_ok);
1237 static __init int setup_noapictimer(char *str)
1239 if (str[0] != ' ' && str[0] != 0)
1241 disable_apic_timer = 1;
1244 __setup("noapictimer", setup_noapictimer);
1246 static __init int setup_apicpmtimer(char *s)
1248 apic_calibrate_pmtmr = 1;
1252 __setup("apicpmtimer", setup_apicpmtimer);