/*
 *      Local APIC handling, local APIC timers
 *
 *      (c) 1999, 2000 Ingo Molnar <mingo@redhat.com>
 *
 *      Fixes
 *      Maciej W. Rozycki       :       Bits for genuine 82489DX APICs;
 *                                      thanks to Eric Gilmore
 *                                      and Rolf G. Tews
 *                                      for testing these extensively.
 *      Maciej W. Rozycki       :       Various updates and fixes.
 *      Mikael Pettersson       :       Power Management for UP-APIC.
 */

#include <linux/config.h>
#include <linux/init.h>

#include <linux/mm.h>
#include <linux/irq.h>
#include <linux/delay.h>
#include <linux/bootmem.h>
#include <linux/smp_lock.h>
#include <linux/interrupt.h>
#include <linux/mc146818rtc.h>
#include <linux/kernel_stat.h>

#include <asm/atomic.h>
#include <asm/smp.h>
#include <asm/mtrr.h>
#include <asm/mpspec.h>
#include <asm/pgalloc.h>
#include <asm/smpboot.h>

/* Using APIC to generate smp_local_timer_interrupt? */
int using_apic_timer = 0;

int prof_multiplier[NR_CPUS] = { 1, };
int prof_old_multiplier[NR_CPUS] = { 1, };
int prof_counter[NR_CPUS] = { 1, };

int get_maxlvt(void)
{
        unsigned int v, ver, maxlvt;

        v = apic_read(APIC_LVR);
        ver = GET_APIC_VERSION(v);
        /* 82489DXs do not report # of LVT entries. */
        maxlvt = APIC_INTEGRATED(ver) ? GET_APIC_MAXLVT(v) : 2;
        return maxlvt;
}

void clear_local_APIC(void)
{
        int maxlvt;
        unsigned long v;

        maxlvt = get_maxlvt();

        /*
         * Masking an LVT entry on a P6 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_around(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_around(APIC_LVTT, v | APIC_LVT_MASKED);
        v = apic_read(APIC_LVT0);
        apic_write_around(APIC_LVT0, v | APIC_LVT_MASKED);
        v = apic_read(APIC_LVT1);
        apic_write_around(APIC_LVT1, v | APIC_LVT_MASKED);
        if (maxlvt >= 4) {
                v = apic_read(APIC_LVTPC);
                apic_write_around(APIC_LVTPC, v | APIC_LVT_MASKED);
        }

        /*
         * Clean APIC state for other OSs:
         */
        apic_write_around(APIC_LVTT, APIC_LVT_MASKED);
        apic_write_around(APIC_LVT0, APIC_LVT_MASKED);
        apic_write_around(APIC_LVT1, APIC_LVT_MASKED);
        if (maxlvt >= 3)
                apic_write_around(APIC_LVTERR, APIC_LVT_MASKED);
        if (maxlvt >= 4)
                apic_write_around(APIC_LVTPC, APIC_LVT_MASKED);
        v = GET_APIC_VERSION(apic_read(APIC_LVR));
        if (APIC_INTEGRATED(v)) {       /* !82489DX */
                if (maxlvt > 3)
                        apic_write(APIC_ESR, 0);
                apic_read(APIC_ESR);
        }
}

void __init connect_bsp_APIC(void)
{
        if (pic_mode) {
                /*
                 * Do not trust the local APIC being empty at bootup.
                 */
                clear_local_APIC();
                /*
                 * PIC mode, enable APIC mode in the IMCR, i.e.
                 * connect BSP's local APIC to INT and NMI lines.
                 */
                printk("leaving PIC mode, enabling APIC mode.\n");
                outb(0x70, 0x22);
                outb(0x01, 0x23);
        }
}

void disconnect_bsp_APIC(void)
{
        if (pic_mode) {
                /*
                 * Put the board back into PIC mode (has an effect
                 * only on certain older boards).  Note that APIC
                 * interrupts, including IPIs, won't work beyond
                 * this point!  The only exception are INIT IPIs.
                 */
                printk("disabling APIC mode, entering PIC mode.\n");
                outb(0x70, 0x22);
                outb(0x00, 0x23);
        }
}

void disable_local_APIC(void)
{
        unsigned long value;

        clear_local_APIC();

        /*
         * Disable APIC (implies clearing of registers
         * for 82489DX!).
         */
        value = apic_read(APIC_SPIV);
        value &= ~APIC_SPIV_APIC_ENABLED;
        apic_write_around(APIC_SPIV, value);
}

/*
 * 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;

        /*
         * The version register is read-only in a real APIC.
         */
        reg0 = apic_read(APIC_LVR);
        Dprintk("Getting VERSION: %x\n", reg0);
        apic_write(APIC_LVR, reg0 ^ APIC_LVR_MASK);
        reg1 = apic_read(APIC_LVR);
        Dprintk("Getting VERSION: %x\n", reg1);

        /*
         * The two version reads above should print the same
         * numbers.  If the second one is different, then we
         * poke at a non-APIC.
         */
        if (reg1 != reg0)
                return 0;

        /*
         * Check if the version looks reasonably.
         */
        reg1 = GET_APIC_VERSION(reg0);
        if (reg1 == 0x00 || reg1 == 0xff)
                return 0;
        reg1 = get_maxlvt();
        if (reg1 < 0x02 || reg1 == 0xff)
                return 0;

        /*
         * The ID register is read/write in a real APIC.
         */
        reg0 = apic_read(APIC_ID);
        Dprintk("Getting ID: %x\n", reg0);
        apic_write(APIC_ID, reg0 ^ APIC_ID_MASK);
        reg1 = apic_read(APIC_ID);
        Dprintk("Getting ID: %x\n", reg1);
        apic_write(APIC_ID, reg0);
        if (reg1 != (reg0 ^ APIC_ID_MASK))
                return 0;

        /*
         * The next two are just to see if we have sane values.
         * They're only really relevant if we're in Virtual Wire
         * compatibility mode, but most boxes are anymore.
         */
        reg0 = apic_read(APIC_LVT0);
        Dprintk("Getting LVT0: %x\n", reg0);
        reg1 = apic_read(APIC_LVT1);
        Dprintk("Getting LVT1: %x\n", reg1);

        return 1;
}

void __init sync_Arb_IDs(void)
{
        /*
         * Wait for idle.
         */
        apic_wait_icr_idle();

        Dprintk("Synchronizing Arb IDs.\n");
        apic_write_around(APIC_ICR, APIC_DEST_ALLINC | APIC_INT_LEVELTRIG
                                | APIC_DM_INIT);
}

extern void __error_in_apic_c (void);

/*
 * An initial setup of the virtual wire mode.
 */
void __init init_bsp_APIC(void)
{
        unsigned long value, ver;

        /*
         * Don't do the setup now if we have a SMP BIOS as the
         * through-I/O-APIC virtual wire mode might be active.
         */
        if (smp_found_config || !cpu_has_apic)
                return;

        value = apic_read(APIC_LVR);
        ver = GET_APIC_VERSION(value);

        /*
         * Do not trust the local APIC being empty at bootup.
         */
        clear_local_APIC();

        /*
         * Enable APIC.
         */
        value = apic_read(APIC_SPIV);
        value &= ~APIC_VECTOR_MASK;
        value |= APIC_SPIV_APIC_ENABLED;
        value |= APIC_SPIV_FOCUS_DISABLED;
        value |= SPURIOUS_APIC_VECTOR;
        apic_write_around(APIC_SPIV, value);

        /*
         * Set up the virtual wire mode.
         */
        apic_write_around(APIC_LVT0, APIC_DM_EXTINT);
        value = APIC_DM_NMI;
        if (!APIC_INTEGRATED(ver))              /* 82489DX */
                value |= APIC_LVT_LEVEL_TRIGGER;
        apic_write_around(APIC_LVT1, value);
}

static unsigned long calculate_ldr(unsigned long old)
{
        unsigned long id;
        if(clustered_apic_mode == CLUSTERED_APIC_XAPIC)
                id = physical_to_logical_apicid(hard_smp_processor_id());
        else
                id = 1UL << smp_processor_id();
        return (old & ~APIC_LDR_MASK)|SET_APIC_LOGICAL_ID(id);
}

void __init setup_local_APIC (void)
{
        unsigned long value, ver, maxlvt;

        /* Pound the ESR really hard over the head with a big hammer - mbligh */
        if (esr_disable) {
                apic_write(APIC_ESR, 0);
                apic_write(APIC_ESR, 0);
                apic_write(APIC_ESR, 0);
                apic_write(APIC_ESR, 0);
        }

        value = apic_read(APIC_LVR);
        ver = GET_APIC_VERSION(value);

        if ((SPURIOUS_APIC_VECTOR & 0x0f) != 0x0f)
                __error_in_apic_c();

        /*
         * Double-check wether this APIC is really registered.
         * This is meaningless in clustered apic mode, so we skip it.
         */
        if (!clustered_apic_mode && 
            !test_bit(GET_APIC_ID(apic_read(APIC_ID)), &phys_cpu_present_map))
                BUG();

        /*
         * Intel recommends to set DFR, LDR and TPR before enabling
         * an APIC.  See e.g. "AP-388 82489DX User's Manual" (Intel
         * document number 292116).  So here it goes...
         */
        if (clustered_apic_mode != CLUSTERED_APIC_NUMAQ) {
                /*
                 * For NUMA-Q (clustered apic logical), the firmware does this
                 * for us. Otherwise put the APIC into clustered or flat
                 * delivery mode. Must be "all ones" explicitly for 82489DX.
                 */
                if(clustered_apic_mode == CLUSTERED_APIC_XAPIC)
                        apic_write_around(APIC_DFR, APIC_DFR_CLUSTER);
                else
                        apic_write_around(APIC_DFR, APIC_DFR_FLAT);

                /*
                 * Set up the logical destination ID.
                 */
                value = apic_read(APIC_LDR);
                apic_write_around(APIC_LDR, calculate_ldr(value));
        }

        /*
         * Set Task Priority to 'accept all'. We never change this
         * later on.
         */
        value = apic_read(APIC_TASKPRI);
        value &= ~APIC_TPRI_MASK;
        apic_write_around(APIC_TASKPRI, value);

        /*
         * Now that we are all set up, enable the APIC
         */
        value = apic_read(APIC_SPIV);
        value &= ~APIC_VECTOR_MASK;
        /*
         * Enable APIC
         */
        value |= APIC_SPIV_APIC_ENABLED;

        /*
         * Some unknown Intel IO/APIC (or APIC) errata is biting us with
         * certain networking cards. If high frequency interrupts are
         * happening on a particular IOAPIC pin, plus the IOAPIC routing
         * entry is masked/unmasked at a high rate as well then sooner or
         * later IOAPIC line gets 'stuck', no more interrupts are received
         * from the device. If focus CPU is disabled then the hang goes
         * away, oh well :-(
         *
         * [ This bug can be reproduced easily with a level-triggered
         *   PCI Ne2000 networking cards and PII/PIII processors, dual
         *   BX chipset. ]
         */
        /*
         * Actually disabling the focus CPU check just makes the hang less
         * frequent as it makes the interrupt distributon model be more
         * like LRU than MRU (the short-term load is more even across CPUs).
         * See also the comment in end_level_ioapic_irq().  --macro
         */
#if 1
        /* Enable focus processor (bit==0) */
        value &= ~APIC_SPIV_FOCUS_DISABLED;
#else
        /* Disable focus processor (bit==1) */
        value |= APIC_SPIV_FOCUS_DISABLED;
#endif
        /*
         * Set spurious IRQ vector
         */
        value |= SPURIOUS_APIC_VECTOR;
        apic_write_around(APIC_SPIV, value);

        /*
         * Set up LVT0, LVT1:
         *
         * set up through-local-APIC on the BP's LINT0. This is not
         * strictly necessery in pure symmetric-IO mode, but sometimes
         * we delegate interrupts to the 8259A.
         */
        /*
         * TODO: set up through-local-APIC from through-I/O-APIC? --macro
         */
        value = apic_read(APIC_LVT0) & APIC_LVT_MASKED;
        if (!smp_processor_id() && (pic_mode || !value)) {
                value = APIC_DM_EXTINT;
                printk("enabled ExtINT on CPU#%d\n", smp_processor_id());
        } else {
                value = APIC_DM_EXTINT | APIC_LVT_MASKED;
                printk("masked ExtINT on CPU#%d\n", smp_processor_id());
        }
        apic_write_around(APIC_LVT0, value);

        /*
         * only the BP should see the LINT1 NMI signal, obviously.
         */
        if (!smp_processor_id())
                value = APIC_DM_NMI;
        else
                value = APIC_DM_NMI | APIC_LVT_MASKED;
        if (!APIC_INTEGRATED(ver))              /* 82489DX */
                value |= APIC_LVT_LEVEL_TRIGGER;
        apic_write_around(APIC_LVT1, value);

        if (APIC_INTEGRATED(ver) && !esr_disable) {             /* !82489DX */
                maxlvt = get_maxlvt();
                if (maxlvt > 3)         /* Due to the Pentium erratum 3AP. */
                        apic_write(APIC_ESR, 0);
                value = apic_read(APIC_ESR);
                printk("ESR value before enabling vector: %08lx\n", value);

                value = ERROR_APIC_VECTOR;      // enables sending errors
                apic_write_around(APIC_LVTERR, value);
                /*
                 * spec says clear errors after enabling vector.
                 */
                if (maxlvt > 3)
                        apic_write(APIC_ESR, 0);
                value = apic_read(APIC_ESR);
                printk("ESR value after enabling vector: %08lx\n", value);
        } else {
                if (esr_disable)        
                        /* 
                         * Something untraceble is creating bad interrupts on 
                         * secondary quads ... for the moment, just leave the
                         * ESR disabled - we can't do anything useful with the
                         * errors anyway - mbligh
                         */
                        printk("Leaving ESR disabled.\n");
                else 
                        printk("No ESR for 82489DX.\n");
        }

        if (nmi_watchdog == NMI_LOCAL_APIC)
                setup_apic_nmi_watchdog();
}

#ifdef CONFIG_PM

#include <linux/slab.h>
#include <linux/pm.h>

static struct {
        /* 'active' is true if the local APIC was enabled by us and
           not the BIOS; this signifies that we are also responsible
           for disabling it before entering apm/acpi suspend */
        int active;
        /* 'perfctr_pmdev' is here because the current (2.4.1) PM
           callback system doesn't handle hierarchical dependencies */
        struct pm_dev *perfctr_pmdev;
        /* r/w apic fields */
        unsigned int apic_id;
        unsigned int apic_taskpri;
        unsigned int apic_ldr;
        unsigned int apic_dfr;
        unsigned int apic_spiv;
        unsigned int apic_lvtt;
        unsigned int apic_lvtpc;
        unsigned int apic_lvt0;
        unsigned int apic_lvt1;
        unsigned int apic_lvterr;
        unsigned int apic_tmict;
        unsigned int apic_tdcr;
} apic_pm_state;

static void apic_pm_suspend(void *data)
{
        unsigned int l, h;
        unsigned long flags;

        if (apic_pm_state.perfctr_pmdev)
                pm_send(apic_pm_state.perfctr_pmdev, PM_SUSPEND, data);
        apic_pm_state.apic_id = apic_read(APIC_ID);
        apic_pm_state.apic_taskpri = apic_read(APIC_TASKPRI);
        apic_pm_state.apic_ldr = apic_read(APIC_LDR);
        apic_pm_state.apic_dfr = apic_read(APIC_DFR);
        apic_pm_state.apic_spiv = apic_read(APIC_SPIV);
        apic_pm_state.apic_lvtt = apic_read(APIC_LVTT);
        apic_pm_state.apic_lvtpc = apic_read(APIC_LVTPC);
        apic_pm_state.apic_lvt0 = apic_read(APIC_LVT0);
        apic_pm_state.apic_lvt1 = apic_read(APIC_LVT1);
        apic_pm_state.apic_lvterr = apic_read(APIC_LVTERR);
        apic_pm_state.apic_tmict = apic_read(APIC_TMICT);
        apic_pm_state.apic_tdcr = apic_read(APIC_TDCR);
        __save_flags(flags);
        __cli();
        disable_local_APIC();
        rdmsr(MSR_IA32_APICBASE, l, h);
        l &= ~MSR_IA32_APICBASE_ENABLE;
        wrmsr(MSR_IA32_APICBASE, l, h);
        __restore_flags(flags);
}

static void apic_pm_resume(void *data)
{
        unsigned int l, h;
        unsigned long flags;

        __save_flags(flags);
        __cli();
        rdmsr(MSR_IA32_APICBASE, l, h);
        l &= ~MSR_IA32_APICBASE_BASE;
        l |= MSR_IA32_APICBASE_ENABLE | APIC_DEFAULT_PHYS_BASE;
        wrmsr(MSR_IA32_APICBASE, l, h);
        apic_write(APIC_LVTERR, ERROR_APIC_VECTOR | APIC_LVT_MASKED);
        apic_write(APIC_ID, apic_pm_state.apic_id);
        apic_write(APIC_DFR, apic_pm_state.apic_dfr);
        apic_write(APIC_LDR, apic_pm_state.apic_ldr);
        apic_write(APIC_TASKPRI, apic_pm_state.apic_taskpri);
        apic_write(APIC_SPIV, apic_pm_state.apic_spiv);
        apic_write(APIC_LVT0, apic_pm_state.apic_lvt0);
        apic_write(APIC_LVT1, apic_pm_state.apic_lvt1);
        apic_write(APIC_LVTPC, apic_pm_state.apic_lvtpc);
        apic_write(APIC_LVTT, apic_pm_state.apic_lvtt);
        apic_write(APIC_TDCR, apic_pm_state.apic_tdcr);
        apic_write(APIC_TMICT, apic_pm_state.apic_tmict);
        apic_write(APIC_ESR, 0);
        apic_read(APIC_ESR);
        apic_write(APIC_LVTERR, apic_pm_state.apic_lvterr);
        apic_write(APIC_ESR, 0);
        apic_read(APIC_ESR);
        __restore_flags(flags);
        if (apic_pm_state.perfctr_pmdev)
                pm_send(apic_pm_state.perfctr_pmdev, PM_RESUME, data);
}

static int apic_pm_callback(struct pm_dev *dev, pm_request_t rqst, void *data)
{
        switch (rqst) {
        case PM_SUSPEND:
                apic_pm_suspend(data);
                break;
        case PM_RESUME:
                apic_pm_resume(data);
                break;
        }
        return 0;
}

/* perfctr driver should call this instead of pm_register() */
struct pm_dev *apic_pm_register(pm_dev_t type,
                                unsigned long id,
                                pm_callback callback)
{
        struct pm_dev *dev;

        if (!apic_pm_state.active)
                return pm_register(type, id, callback);
        if (apic_pm_state.perfctr_pmdev)
                return NULL;    /* we're busy */
        dev = kmalloc(sizeof(struct pm_dev), GFP_KERNEL);
        if (dev) {
                memset(dev, 0, sizeof(*dev));
                dev->type = type;
                dev->id = id;
                dev->callback = callback;
                apic_pm_state.perfctr_pmdev = dev;
        }
        return dev;
}

/* perfctr driver should call this instead of pm_unregister() */
void apic_pm_unregister(struct pm_dev *dev)
{
        if (!apic_pm_state.active) {
                pm_unregister(dev);
        } else if (dev == apic_pm_state.perfctr_pmdev) {
                apic_pm_state.perfctr_pmdev = NULL;
                kfree(dev);
        }
}

static void __init apic_pm_init1(void)
{
        /* can't pm_register() at this early stage in the boot process
           (causes an immediate reboot), so just set the flag */
        apic_pm_state.active = 1;
}

static void __init apic_pm_init2(void)
{
        if (apic_pm_state.active)
                pm_register(PM_SYS_DEV, 0, apic_pm_callback);
}

#else   /* CONFIG_PM */

static inline void apic_pm_init1(void) { }
static inline void apic_pm_init2(void) { }

#endif  /* CONFIG_PM */

/*
 * Detect and enable local APICs on non-SMP boards.
 * Original code written by Keir Fraser.
 */
int dont_enable_local_apic __initdata = 0;

static int __init detect_init_APIC (void)
{
        u32 h, l, features;
        extern void get_cpu_vendor(struct cpuinfo_x86*);

        /* Disabled by DMI scan or kernel option? */
        if (dont_enable_local_apic)
                return -1;

        /* Workaround for us being called before identify_cpu(). */
        get_cpu_vendor(&boot_cpu_data);

        switch (boot_cpu_data.x86_vendor) {
        case X86_VENDOR_AMD:
                if (boot_cpu_data.x86 == 6 && boot_cpu_data.x86_model > 1)
                        break;
                if (boot_cpu_data.x86 == 15 && cpu_has_apic)
                        break;
                goto no_apic;
        case X86_VENDOR_INTEL:
                if (boot_cpu_data.x86 == 6 ||
                    (boot_cpu_data.x86 == 15 && cpu_has_apic) ||
                    (boot_cpu_data.x86 == 5 && cpu_has_apic))
                        break;
                goto no_apic;
        default:
                goto no_apic;
        }

        if (!cpu_has_apic) {
                /*
                 * Some BIOSes disable the local APIC in the
                 * APIC_BASE MSR. This can only be done in
                 * software for Intel P6 and AMD K7 (Model > 1).
                 */
                rdmsr(MSR_IA32_APICBASE, l, h);
                if (!(l & MSR_IA32_APICBASE_ENABLE)) {
                        printk("Local APIC disabled by BIOS -- reenabling.\n");
                        l &= ~MSR_IA32_APICBASE_BASE;
                        l |= MSR_IA32_APICBASE_ENABLE | APIC_DEFAULT_PHYS_BASE;
                        wrmsr(MSR_IA32_APICBASE, l, h);
                }
        }
        /*
         * The APIC feature bit should now be enabled
         * in `cpuid'
         */
        features = cpuid_edx(1);
        if (!(features & (1 << X86_FEATURE_APIC))) {
                printk("Could not enable APIC!\n");
                return -1;
        }
        set_bit(X86_FEATURE_APIC, &boot_cpu_data.x86_capability);
        mp_lapic_addr = APIC_DEFAULT_PHYS_BASE;
        if (nmi_watchdog != NMI_NONE)
                nmi_watchdog = NMI_LOCAL_APIC;

        printk("Found and enabled local APIC!\n");

        apic_pm_init1();

        return 0;

no_apic:
        printk("No local APIC present or hardware disabled\n");
        return -1;
}

void __init init_apic_mappings(void)
{
        unsigned long apic_phys;

        /*
         * If no local APIC can be found then set up a fake all
         * zeroes page to simulate the local APIC and another
         * one for the IO-APIC.
         */
        if (!smp_found_config && detect_init_APIC()) {
                apic_phys = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
                apic_phys = __pa(apic_phys);
        } else
                apic_phys = mp_lapic_addr;

        set_fixmap_nocache(FIX_APIC_BASE, apic_phys);
        Dprintk("mapped APIC to %08lx (%08lx)\n", APIC_BASE, apic_phys);

        /*
         * Fetch the APIC ID of the BSP in case we have a
         * default configuration (or the MP table is broken).
         */
        if (boot_cpu_physical_apicid == -1U)
                boot_cpu_physical_apicid = GET_APIC_ID(apic_read(APIC_ID));

#ifdef CONFIG_X86_IO_APIC
        {
                unsigned long ioapic_phys, idx = FIX_IO_APIC_BASE_0;
                int i;

                for (i = 0; i < nr_ioapics; i++) {
                        if (smp_found_config) {
                                ioapic_phys = mp_ioapics[i].mpc_apicaddr;
                                if (!ioapic_phys) {
                                        printk(KERN_ERR "WARNING: bogus zero IO-APIC address found in MPTABLE, disabling IO/APIC support!\n");

                                        smp_found_config = 0;
                                        skip_ioapic_setup = 1;
                                        goto fake_ioapic_page;
                                }
                        } else {
fake_ioapic_page:
                                ioapic_phys = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
                                ioapic_phys = __pa(ioapic_phys);
                        }
                        set_fixmap_nocache(idx, ioapic_phys);
                        Dprintk("mapped IOAPIC to %08lx (%08lx)\n",
                                        __fix_to_virt(idx), ioapic_phys);
                        idx++;
                }
        }
#endif
}

/*
 * This part sets up the APIC 32 bit clock in LVTT1, with HZ interrupts
 * per second. We assume that the caller has already set up the local
 * APIC.
 *
 * The APIC timer is not exactly sync with the external timer chip, it
 * closely follows bus clocks.
 */

/*
 * The timer chip is already set up at HZ interrupts per second here,
 * but we do not accept timer interrupts yet. We only allow the BP
 * to calibrate.
 */
static unsigned int __init get_8254_timer_count(void)
{
        extern spinlock_t i8253_lock;
        unsigned long flags;

        unsigned int count;

        spin_lock_irqsave(&i8253_lock, flags);

        outb_p(0x00, 0x43);
        count = inb_p(0x40);
        count |= inb_p(0x40) << 8;

        spin_unlock_irqrestore(&i8253_lock, flags);

        return count;
}

void __init wait_8254_wraparound(void)
{
        unsigned int curr_count, prev_count=~0;
        int delta;

        curr_count = get_8254_timer_count();

        do {
                prev_count = curr_count;
                curr_count = get_8254_timer_count();
                delta = curr_count-prev_count;

        /*
         * This limit for delta seems arbitrary, but it isn't, it's
         * slightly above the level of error a buggy Mercury/Neptune
         * chipset timer can cause.
         */

        } while (delta < 300);
}

/*
 * This function sets up the local APIC timer, with a timeout of
 * 'clocks' APIC bus clock. During calibration we actually call
 * this function twice on the boot CPU, once with a bogus timeout
 * value, second time for real. The other (noncalibrating) CPUs
 * call this function only once, with the real, calibrated value.
 *
 * We do reads before writes even if unnecessary, to get around the
 * P5 APIC double write bug.
 */

#define APIC_DIVISOR 16

void __setup_APIC_LVTT(unsigned int clocks)
{
        unsigned int lvtt1_value, tmp_value;

        lvtt1_value = SET_APIC_TIMER_BASE(APIC_TIMER_BASE_DIV) |
                        APIC_LVT_TIMER_PERIODIC | LOCAL_TIMER_VECTOR;
        apic_write_around(APIC_LVTT, lvtt1_value);

        /*
         * Divide PICLK by 16
         */
        tmp_value = apic_read(APIC_TDCR);
        apic_write_around(APIC_TDCR, (tmp_value
                                & ~(APIC_TDR_DIV_1 | APIC_TDR_DIV_TMBASE))
                                | APIC_TDR_DIV_16);

        apic_write_around(APIC_TMICT, clocks/APIC_DIVISOR);
}

void setup_APIC_timer(void * data)
{
        unsigned int clocks = (unsigned int) data, slice, t0, t1;
        unsigned long flags;
        int delta;

        __save_flags(flags);
        __sti();
        /*
         * ok, Intel has some smart code in their APIC that knows
         * if a CPU was in 'hlt' lowpower mode, and this increases
         * its APIC arbitration priority. To avoid the external timer
         * IRQ APIC event being in synchron with the APIC clock we
         * introduce an interrupt skew to spread out timer events.
         *
         * The number of slices within a 'big' timeslice is smp_num_cpus+1
         */

        slice = clocks / (smp_num_cpus+1);
        printk("cpu: %d, clocks: %d, slice: %d\n", smp_processor_id(), clocks, slice);

        /*
         * Wait for IRQ0's slice:
         */
        wait_8254_wraparound();

        __setup_APIC_LVTT(clocks);

        t0 = apic_read(APIC_TMICT)*APIC_DIVISOR;
        /* Wait till TMCCT gets reloaded from TMICT... */
        do {
                t1 = apic_read(APIC_TMCCT)*APIC_DIVISOR;
                delta = (int)(t0 - t1 - slice*(smp_processor_id()+1));
        } while (delta >= 0);
        /* Now wait for our slice for real. */
        do {
                t1 = apic_read(APIC_TMCCT)*APIC_DIVISOR;
                delta = (int)(t0 - t1 - slice*(smp_processor_id()+1));
        } while (delta < 0);

        __setup_APIC_LVTT(clocks);

        printk("CPU%d<T0:%d,T1:%d,D:%d,S:%d,C:%d>\n", smp_processor_id(), t0, t1, delta, slice, clocks);

        __restore_flags(flags);
}

/*
 * In this function we calibrate APIC bus clocks to the external
 * timer. Unfortunately we cannot use jiffies and the timer irq
 * to calibrate, since some later bootup code depends on getting
 * the first irq? Ugh.
 *
 * We want to do the calibration only once since we
 * want to have local timer irqs syncron. CPUs connected
 * by the same APIC bus have the very same bus frequency.
 * And we want to have irqs off anyways, no accidental
 * APIC irq that way.
 */

int __init calibrate_APIC_clock(void)
{
        unsigned long long t1 = 0, t2 = 0;
        long tt1, tt2;
        long result;
        int i;
        const int LOOPS = HZ/10;

        printk("calibrating APIC timer ...\n");

        /*
         * Put whatever arbitrary (but long enough) timeout
         * value into the APIC clock, we just want to get the
         * counter running for calibration.
         */
        __setup_APIC_LVTT(1000000000);

        /*
         * The timer chip counts down to zero. Let's wait
         * for a wraparound to start exact measurement:
         * (the current tick might have been already half done)
         */

        wait_8254_wraparound();

        /*
         * We wrapped around just now. Let's start:
         */
        if (cpu_has_tsc)
                rdtscll(t1);
        tt1 = apic_read(APIC_TMCCT);

        /*
         * Let's wait LOOPS wraprounds:
         */
        for (i = 0; i < LOOPS; i++)
                wait_8254_wraparound();

        tt2 = apic_read(APIC_TMCCT);
        if (cpu_has_tsc)
                rdtscll(t2);

        /*
         * The APIC bus clock counter is 32 bits only, it
         * might have overflown, but note that we use signed
         * longs, thus no extra care needed.
         *
         * underflown to be exact, as the timer counts down ;)
         */

        result = (tt1-tt2)*APIC_DIVISOR/LOOPS;

        if (cpu_has_tsc)
                printk("..... CPU clock speed is %ld.%04ld MHz.\n",
                        ((long)(t2-t1)/LOOPS)/(1000000/HZ),
                        ((long)(t2-t1)/LOOPS)%(1000000/HZ));

        printk("..... host bus clock speed is %ld.%04ld MHz.\n",
                result/(1000000/HZ),
                result%(1000000/HZ));

        return result;
}

static unsigned int calibration_result;

int dont_use_local_apic_timer __initdata = 0;

void __init setup_APIC_clocks (void)
{
        /* Disabled by DMI scan or kernel option? */
        if (dont_use_local_apic_timer)
                return;

        printk("Using local APIC timer interrupts.\n");
        using_apic_timer = 1;

        __cli();

        calibration_result = calibrate_APIC_clock();
        /*
         * Now set up the timer for real.
         */
        setup_APIC_timer((void *)calibration_result);

        __sti();

        /* and update all other cpus */
        smp_call_function(setup_APIC_timer, (void *)calibration_result, 1, 1);
}

void __init disable_APIC_timer(void)
{
        if (using_apic_timer) {
                unsigned long v;

                v = apic_read(APIC_LVTT);
                apic_write_around(APIC_LVTT, v | APIC_LVT_MASKED);
        }
}

void enable_APIC_timer(void)
{
        if (using_apic_timer) {
                unsigned long v;

                v = apic_read(APIC_LVTT);
                apic_write_around(APIC_LVTT, v & ~APIC_LVT_MASKED);
        }
}

/*
 * the frequency of the profiling timer can be changed
 * by writing a multiplier value into /proc/profile.
 */
int setup_profiling_timer(unsigned int multiplier)
{
        int i;

        /*
         * Sanity check. [at least 500 APIC cycles should be
         * between APIC interrupts as a rule of thumb, to avoid
         * irqs flooding us]
         */
        if ( (!multiplier) || (calibration_result/multiplier < 500))
                return -EINVAL;

        /* 
         * Set the new multiplier for each CPU. CPUs don't start using the
         * new values until the next timer interrupt in which they do process
         * accounting. At that time they also adjust their APIC timers
         * accordingly.
         */
        for (i = 0; i < NR_CPUS; ++i)
                prof_multiplier[i] = multiplier;

        return 0;
}

#undef APIC_DIVISOR

/*
 * Local timer interrupt handler. It does both profiling and
 * process statistics/rescheduling.
 *
 * We do profiling in every local tick, statistics/rescheduling
 * happen only every 'profiling multiplier' ticks. The default
 * multiplier is 1 and it can be changed by writing the new multiplier
 * value into /proc/profile.
 */

inline void smp_local_timer_interrupt(struct pt_regs * regs)
{
        int user = user_mode(regs);
        int cpu = smp_processor_id();

        /*
         * The profiling function is SMP safe. (nothing can mess
         * around with "current", and the profiling counters are
         * updated with atomic operations). This is especially
         * useful with a profiling multiplier != 1
         */
        if (!user)
                x86_do_profile(regs->eip);

        if (--prof_counter[cpu] <= 0) {
                /*
                 * The multiplier may have changed since the last time we got
                 * to this point as a result of the user writing to
                 * /proc/profile. In this case we need to adjust the APIC
                 * timer accordingly.
                 *
                 * Interrupts are already masked off at this point.
                 */
                prof_counter[cpu] = prof_multiplier[cpu];
                if (prof_counter[cpu] != prof_old_multiplier[cpu]) {
                        __setup_APIC_LVTT(calibration_result/prof_counter[cpu]);
                        prof_old_multiplier[cpu] = prof_counter[cpu];
                }

#ifdef CONFIG_SMP
                update_process_times(user);
#endif
        }

        /*
         * We take the 'long' return path, and there every subsystem
         * grabs the apropriate locks (kernel lock/ irq lock).
         *
         * we might want to decouple profiling from the 'long path',
         * and do the profiling totally in assembly.
         *
         * Currently this isn't too much of an issue (performance wise),
         * we can take more than 100K local irqs per second on a 100 MHz P5.
         */
}

/*
 * 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 ... ]
 */
unsigned int apic_timer_irqs [NR_CPUS];

void smp_apic_timer_interrupt(struct pt_regs * regs)
{
        int cpu = smp_processor_id();

        /*
         * the NMI deadlock-detector uses this.
         */
        apic_timer_irqs[cpu]++;

        /*
         * 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.
         */
        irq_enter(cpu, 0);
        smp_local_timer_interrupt(regs);
        irq_exit(cpu, 0);

        if (softirq_pending(cpu))
                do_softirq();
}

/*
 * This interrupt should _never_ happen with our APIC/SMP architecture
 */
asmlinkage void smp_spurious_interrupt(void)
{
        unsigned long v;

        /*
         * Check if this really is a spurious interrupt and ACK it
         * if it is a vectored one.  Just in case...
         * Spurious interrupts should not be ACKed.
         */
        v = apic_read(APIC_ISR + ((SPURIOUS_APIC_VECTOR & ~0x1f) >> 1));
        if (v & (1 << (SPURIOUS_APIC_VECTOR & 0x1f)))
                ack_APIC_irq();

        /* see sw-dev-man vol 3, chapter 7.4.13.5 */
        printk(KERN_INFO "spurious APIC interrupt on CPU#%d, should never happen.\n",
                        smp_processor_id());
}

/*
 * This interrupt should never happen with our APIC/SMP architecture
 */

asmlinkage void smp_error_interrupt(void)
{
        unsigned long v, v1;

        /* First tickle the hardware, only then report what went on. -- REW */
        v = apic_read(APIC_ESR);
        apic_write(APIC_ESR, 0);
        v1 = apic_read(APIC_ESR);
        ack_APIC_irq();
        atomic_inc(&irq_err_count);

        /* Here is what the APIC error bits mean:
           0: Send CS error
           1: Receive CS error
           2: Send accept error
           3: Receive accept error
           4: Reserved
           5: Send illegal vector
           6: Received illegal vector
           7: Illegal register address
        */
        printk (KERN_ERR "APIC error on CPU%d: %02lx(%02lx)\n",
                smp_processor_id(), v , v1);
}

/*
 * This initializes the IO-APIC and APIC hardware if this is
 * a UP kernel.
 */
int __init APIC_init_uniprocessor (void)
{
        if (!smp_found_config && !cpu_has_apic)
                return -1;

        /*
         * Complain if the BIOS pretends there is one.
         */
        if (!cpu_has_apic && APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid])) {
                printk(KERN_ERR "BIOS bug, local APIC #%d not detected!...\n",
                        boot_cpu_physical_apicid);
                return -1;
        }

        verify_local_APIC();

        connect_bsp_APIC();

        phys_cpu_present_map = 1 << boot_cpu_physical_apicid;

        apic_pm_init2();

        setup_local_APIC();

        if (nmi_watchdog == NMI_LOCAL_APIC)
                check_nmi_watchdog();
#ifdef CONFIG_X86_IO_APIC
        if (smp_found_config)
                if (!skip_ioapic_setup && nr_ioapics)
                        setup_IO_APIC();
#endif
        setup_APIC_clocks();

        return 0;
}