[SPARC64]: Make IVEC pointers 64-bit.

[linux-2.6/mini2440.git] / arch / sparc64 / kernel / irq.c

/* irq.c: UltraSparc IRQ handling/init/registry.
 *
 * Copyright (C) 1997, 2007  David S. Miller  (davem@davemloft.net)
 * Copyright (C) 1998  Eddie C. Dost    (ecd@skynet.be)
 * Copyright (C) 1998  Jakub Jelinek    (jj@ultra.linux.cz)
 */

#include <linux/module.h>
#include <linux/sched.h>
#include <linux/ptrace.h>
#include <linux/errno.h>
#include <linux/kernel_stat.h>
#include <linux/signal.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/bootmem.h>
#include <linux/irq.h>

#include <asm/ptrace.h>
#include <asm/processor.h>
#include <asm/atomic.h>
#include <asm/system.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/sbus.h>
#include <asm/iommu.h>
#include <asm/upa.h>
#include <asm/oplib.h>
#include <asm/prom.h>
#include <asm/timer.h>
#include <asm/smp.h>
#include <asm/starfire.h>
#include <asm/uaccess.h>
#include <asm/cache.h>
#include <asm/cpudata.h>
#include <asm/auxio.h>
#include <asm/head.h>
#include <asm/hypervisor.h>

/* UPA nodes send interrupt packet to UltraSparc with first data reg
 * value low 5 (7 on Starfire) bits holding the IRQ identifier being
 * delivered.  We must translate this into a non-vector IRQ so we can
 * set the softint on this cpu.
 *
 * To make processing these packets efficient and race free we use
 * an array of irq buckets below.  The interrupt vector handler in
 * entry.S feeds incoming packets into per-cpu pil-indexed lists.
 * The IVEC handler does not need to act atomically, the PIL dispatch
 * code uses CAS to get an atomic snapshot of the list and clear it
 * at the same time.
 *
 * If you make changes to ino_bucket, please update hand coded assembler
 * of the vectored interrupt trap handler(s) in entry.S and sun4v_ivec.S
 */
struct ino_bucket {
/*0x00*/unsigned long irq_chain;

        /* Virtual interrupt number assigned to this INO.  */
/*0x08*/unsigned int virt_irq;
/*0x0c*/unsigned int __pad;
};

#define NUM_IVECS       (IMAP_INR + 1)
struct ino_bucket ivector_table[NUM_IVECS] __attribute__ ((aligned (SMP_CACHE_BYTES)));

#define __irq_ino(irq) \
        (((struct ino_bucket *)(irq)) - &ivector_table[0])
#define __bucket(irq) ((struct ino_bucket *)(irq))
#define __irq(bucket) ((unsigned long)(bucket))

/* This has to be in the main kernel image, it cannot be
 * turned into per-cpu data.  The reason is that the main
 * kernel image is locked into the TLB and this structure
 * is accessed from the vectored interrupt trap handler.  If
 * access to this structure takes a TLB miss it could cause
 * the 5-level sparc v9 trap stack to overflow.
 */
#define irq_work(__cpu) &(trap_block[(__cpu)].irq_worklist)

static struct {
        unsigned long irq;
        unsigned int dev_handle;
        unsigned int dev_ino;
} virt_to_real_irq_table[NR_IRQS];
static DEFINE_SPINLOCK(virt_irq_alloc_lock);

unsigned char virt_irq_alloc(unsigned long real_irq)
{
        unsigned long flags;
        unsigned char ent;

        BUILD_BUG_ON(NR_IRQS >= 256);

        spin_lock_irqsave(&virt_irq_alloc_lock, flags);

        for (ent = 1; ent < NR_IRQS; ent++) {
                if (!virt_to_real_irq_table[ent].irq)
                        break;
        }
        if (ent >= NR_IRQS) {
                printk(KERN_ERR "IRQ: Out of virtual IRQs.\n");
                ent = 0;
        } else {
                virt_to_real_irq_table[ent].irq = real_irq;
        }

        spin_unlock_irqrestore(&virt_irq_alloc_lock, flags);

        return ent;
}

#ifdef CONFIG_PCI_MSI
void virt_irq_free(unsigned int virt_irq)
{
        unsigned long flags;

        if (virt_irq >= NR_IRQS)
                return;

        spin_lock_irqsave(&virt_irq_alloc_lock, flags);

        virt_to_real_irq_table[virt_irq].irq = 0;

        spin_unlock_irqrestore(&virt_irq_alloc_lock, flags);
}
#endif

static unsigned long virt_to_real_irq(unsigned char virt_irq)
{
        return virt_to_real_irq_table[virt_irq].irq;
}

/*
 * /proc/interrupts printing:
 */

int show_interrupts(struct seq_file *p, void *v)
{
        int i = *(loff_t *) v, j;
        struct irqaction * action;
        unsigned long flags;

        if (i == 0) {
                seq_printf(p, "           ");
                for_each_online_cpu(j)
                        seq_printf(p, "CPU%d       ",j);
                seq_putc(p, '\n');
        }

        if (i < NR_IRQS) {
                spin_lock_irqsave(&irq_desc[i].lock, flags);
                action = irq_desc[i].action;
                if (!action)
                        goto skip;
                seq_printf(p, "%3d: ",i);
#ifndef CONFIG_SMP
                seq_printf(p, "%10u ", kstat_irqs(i));
#else
                for_each_online_cpu(j)
                        seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
#endif
                seq_printf(p, " %9s", irq_desc[i].chip->typename);
                seq_printf(p, "  %s", action->name);

                for (action=action->next; action; action = action->next)
                        seq_printf(p, ", %s", action->name);

                seq_putc(p, '\n');
skip:
                spin_unlock_irqrestore(&irq_desc[i].lock, flags);
        }
        return 0;
}

static unsigned int sun4u_compute_tid(unsigned long imap, unsigned long cpuid)
{
        unsigned int tid;

        if (this_is_starfire) {
                tid = starfire_translate(imap, cpuid);
                tid <<= IMAP_TID_SHIFT;
                tid &= IMAP_TID_UPA;
        } else {
                if (tlb_type == cheetah || tlb_type == cheetah_plus) {
                        unsigned long ver;

                        __asm__ ("rdpr %%ver, %0" : "=r" (ver));
                        if ((ver >> 32UL) == __JALAPENO_ID ||
                            (ver >> 32UL) == __SERRANO_ID) {
                                tid = cpuid << IMAP_TID_SHIFT;
                                tid &= IMAP_TID_JBUS;
                        } else {
                                unsigned int a = cpuid & 0x1f;
                                unsigned int n = (cpuid >> 5) & 0x1f;

                                tid = ((a << IMAP_AID_SHIFT) |
                                       (n << IMAP_NID_SHIFT));
                                tid &= (IMAP_AID_SAFARI |
                                        IMAP_NID_SAFARI);;
                        }
                } else {
                        tid = cpuid << IMAP_TID_SHIFT;
                        tid &= IMAP_TID_UPA;
                }
        }

        return tid;
}

struct irq_handler_data {
        unsigned long   iclr;
        unsigned long   imap;

        void            (*pre_handler)(unsigned int, void *, void *);
        void            *pre_handler_arg1;
        void            *pre_handler_arg2;
};

static inline struct ino_bucket *virt_irq_to_bucket(unsigned int virt_irq)
{
        unsigned long real_irq = virt_to_real_irq(virt_irq);
        struct ino_bucket *bucket = NULL;

        if (likely(real_irq))
                bucket = __bucket(real_irq);

        return bucket;
}

#ifdef CONFIG_SMP
static int irq_choose_cpu(unsigned int virt_irq)
{
        cpumask_t mask = irq_desc[virt_irq].affinity;
        int cpuid;

        if (cpus_equal(mask, CPU_MASK_ALL)) {
                static int irq_rover;
                static DEFINE_SPINLOCK(irq_rover_lock);
                unsigned long flags;

                /* Round-robin distribution... */
        do_round_robin:
                spin_lock_irqsave(&irq_rover_lock, flags);

                while (!cpu_online(irq_rover)) {
                        if (++irq_rover >= NR_CPUS)
                                irq_rover = 0;
                }
                cpuid = irq_rover;
                do {
                        if (++irq_rover >= NR_CPUS)
                                irq_rover = 0;
                } while (!cpu_online(irq_rover));

                spin_unlock_irqrestore(&irq_rover_lock, flags);
        } else {
                cpumask_t tmp;

                cpus_and(tmp, cpu_online_map, mask);

                if (cpus_empty(tmp))
                        goto do_round_robin;

                cpuid = first_cpu(tmp);
        }

        return cpuid;
}
#else
static int irq_choose_cpu(unsigned int virt_irq)
{
        return real_hard_smp_processor_id();
}
#endif

static void sun4u_irq_enable(unsigned int virt_irq)
{
        struct irq_handler_data *data = get_irq_chip_data(virt_irq);

        if (likely(data)) {
                unsigned long cpuid, imap, val;
                unsigned int tid;

                cpuid = irq_choose_cpu(virt_irq);
                imap = data->imap;

                tid = sun4u_compute_tid(imap, cpuid);

                val = upa_readq(imap);
                val &= ~(IMAP_TID_UPA | IMAP_TID_JBUS |
                         IMAP_AID_SAFARI | IMAP_NID_SAFARI);
                val |= tid | IMAP_VALID;
                upa_writeq(val, imap);
        }
}

static void sun4u_set_affinity(unsigned int virt_irq, cpumask_t mask)
{
        sun4u_irq_enable(virt_irq);
}

static void sun4u_irq_disable(unsigned int virt_irq)
{
        struct irq_handler_data *data = get_irq_chip_data(virt_irq);

        if (likely(data)) {
                unsigned long imap = data->imap;
                unsigned long tmp = upa_readq(imap);

                tmp &= ~IMAP_VALID;
                upa_writeq(tmp, imap);
        }
}

static void sun4u_irq_end(unsigned int virt_irq)
{
        struct irq_handler_data *data = get_irq_chip_data(virt_irq);
        struct irq_desc *desc = irq_desc + virt_irq;

        if (unlikely(desc->status & (IRQ_DISABLED|IRQ_INPROGRESS)))
                return;

        if (likely(data))
                upa_writeq(ICLR_IDLE, data->iclr);
}

static void sun4v_irq_enable(unsigned int virt_irq)
{
        struct ino_bucket *bucket = virt_irq_to_bucket(virt_irq);
        unsigned int ino = bucket - &ivector_table[0];

        if (likely(bucket)) {
                unsigned long cpuid;
                int err;

                cpuid = irq_choose_cpu(virt_irq);

                err = sun4v_intr_settarget(ino, cpuid);
                if (err != HV_EOK)
                        printk(KERN_ERR "sun4v_intr_settarget(%x,%lu): "
                               "err(%d)\n", ino, cpuid, err);
                err = sun4v_intr_setstate(ino, HV_INTR_STATE_IDLE);
                if (err != HV_EOK)
                        printk(KERN_ERR "sun4v_intr_setstate(%x): "
                               "err(%d)\n", ino, err);
                err = sun4v_intr_setenabled(ino, HV_INTR_ENABLED);
                if (err != HV_EOK)
                        printk(KERN_ERR "sun4v_intr_setenabled(%x): err(%d)\n",
                               ino, err);
        }
}

static void sun4v_set_affinity(unsigned int virt_irq, cpumask_t mask)
{
        struct ino_bucket *bucket = virt_irq_to_bucket(virt_irq);
        unsigned int ino = bucket - &ivector_table[0];

        if (likely(bucket)) {
                unsigned long cpuid;
                int err;

                cpuid = irq_choose_cpu(virt_irq);

                err = sun4v_intr_settarget(ino, cpuid);
                if (err != HV_EOK)
                        printk(KERN_ERR "sun4v_intr_settarget(%x,%lu): "
                               "err(%d)\n", ino, cpuid, err);
        }
}

static void sun4v_irq_disable(unsigned int virt_irq)
{
        struct ino_bucket *bucket = virt_irq_to_bucket(virt_irq);
        unsigned int ino = bucket - &ivector_table[0];

        if (likely(bucket)) {
                int err;

                err = sun4v_intr_setenabled(ino, HV_INTR_DISABLED);
                if (err != HV_EOK)
                        printk(KERN_ERR "sun4v_intr_setenabled(%x): "
                               "err(%d)\n", ino, err);
        }
}

static void sun4v_irq_end(unsigned int virt_irq)
{
        struct ino_bucket *bucket = virt_irq_to_bucket(virt_irq);
        unsigned int ino = bucket - &ivector_table[0];
        struct irq_desc *desc = irq_desc + virt_irq;

        if (unlikely(desc->status & (IRQ_DISABLED|IRQ_INPROGRESS)))
                return;

        if (likely(bucket)) {
                int err;

                err = sun4v_intr_setstate(ino, HV_INTR_STATE_IDLE);
                if (err != HV_EOK)
                        printk(KERN_ERR "sun4v_intr_setstate(%x): "
                               "err(%d)\n", ino, err);
        }
}

static void sun4v_virq_enable(unsigned int virt_irq)
{
        struct ino_bucket *bucket = virt_irq_to_bucket(virt_irq);

        if (likely(bucket)) {
                unsigned long cpuid, dev_handle, dev_ino;
                int err;

                cpuid = irq_choose_cpu(virt_irq);

                dev_handle = virt_to_real_irq_table[virt_irq].dev_handle;
                dev_ino = virt_to_real_irq_table[virt_irq].dev_ino;

                err = sun4v_vintr_set_target(dev_handle, dev_ino, cpuid);
                if (err != HV_EOK)
                        printk(KERN_ERR "sun4v_vintr_set_target(%lx,%lx,%lu): "
                               "err(%d)\n",
                               dev_handle, dev_ino, cpuid, err);
                err = sun4v_vintr_set_state(dev_handle, dev_ino,
                                            HV_INTR_STATE_IDLE);
                if (err != HV_EOK)
                        printk(KERN_ERR "sun4v_vintr_set_state(%lx,%lx,"
                                "HV_INTR_STATE_IDLE): err(%d)\n",
                               dev_handle, dev_ino, err);
                err = sun4v_vintr_set_valid(dev_handle, dev_ino,
                                            HV_INTR_ENABLED);
                if (err != HV_EOK)
                        printk(KERN_ERR "sun4v_vintr_set_state(%lx,%lx,"
                               "HV_INTR_ENABLED): err(%d)\n",
                               dev_handle, dev_ino, err);
        }
}

static void sun4v_virt_set_affinity(unsigned int virt_irq, cpumask_t mask)
{
        struct ino_bucket *bucket = virt_irq_to_bucket(virt_irq);

        if (likely(bucket)) {
                unsigned long cpuid, dev_handle, dev_ino;
                int err;

                cpuid = irq_choose_cpu(virt_irq);

                dev_handle = virt_to_real_irq_table[virt_irq].dev_handle;
                dev_ino = virt_to_real_irq_table[virt_irq].dev_ino;

                err = sun4v_vintr_set_target(dev_handle, dev_ino, cpuid);
                if (err != HV_EOK)
                        printk(KERN_ERR "sun4v_vintr_set_target(%lx,%lx,%lu): "
                               "err(%d)\n",
                               dev_handle, dev_ino, cpuid, err);
        }
}

static void sun4v_virq_disable(unsigned int virt_irq)
{
        struct ino_bucket *bucket = virt_irq_to_bucket(virt_irq);

        if (likely(bucket)) {
                unsigned long dev_handle, dev_ino;
                int err;

                dev_handle = virt_to_real_irq_table[virt_irq].dev_handle;
                dev_ino = virt_to_real_irq_table[virt_irq].dev_ino;

                err = sun4v_vintr_set_valid(dev_handle, dev_ino,
                                            HV_INTR_DISABLED);
                if (err != HV_EOK)
                        printk(KERN_ERR "sun4v_vintr_set_state(%lx,%lx,"
                               "HV_INTR_DISABLED): err(%d)\n",
                               dev_handle, dev_ino, err);
        }
}

static void sun4v_virq_end(unsigned int virt_irq)
{
        struct ino_bucket *bucket = virt_irq_to_bucket(virt_irq);
        struct irq_desc *desc = irq_desc + virt_irq;

        if (unlikely(desc->status & (IRQ_DISABLED|IRQ_INPROGRESS)))
                return;

        if (likely(bucket)) {
                unsigned long dev_handle, dev_ino;
                int err;

                dev_handle = virt_to_real_irq_table[virt_irq].dev_handle;
                dev_ino = virt_to_real_irq_table[virt_irq].dev_ino;

                err = sun4v_vintr_set_state(dev_handle, dev_ino,
                                            HV_INTR_STATE_IDLE);
                if (err != HV_EOK)
                        printk(KERN_ERR "sun4v_vintr_set_state(%lx,%lx,"
                                "HV_INTR_STATE_IDLE): err(%d)\n",
                               dev_handle, dev_ino, err);
        }
}

static void run_pre_handler(unsigned int virt_irq)
{
        struct ino_bucket *bucket = virt_irq_to_bucket(virt_irq);
        struct irq_handler_data *data = get_irq_chip_data(virt_irq);

        if (likely(data->pre_handler)) {
                data->pre_handler(__irq_ino(__irq(bucket)),
                                  data->pre_handler_arg1,
                                  data->pre_handler_arg2);
        }
}

static struct irq_chip sun4u_irq = {
        .typename       = "sun4u",
        .enable         = sun4u_irq_enable,
        .disable        = sun4u_irq_disable,
        .end            = sun4u_irq_end,
        .set_affinity   = sun4u_set_affinity,
};

static struct irq_chip sun4u_irq_ack = {
        .typename       = "sun4u+ack",
        .enable         = sun4u_irq_enable,
        .disable        = sun4u_irq_disable,
        .ack            = run_pre_handler,
        .end            = sun4u_irq_end,
        .set_affinity   = sun4u_set_affinity,
};

static struct irq_chip sun4v_irq = {
        .typename       = "sun4v",
        .enable         = sun4v_irq_enable,
        .disable        = sun4v_irq_disable,
        .end            = sun4v_irq_end,
        .set_affinity   = sun4v_set_affinity,
};

static struct irq_chip sun4v_virq = {
        .typename       = "vsun4v",
        .enable         = sun4v_virq_enable,
        .disable        = sun4v_virq_disable,
        .end            = sun4v_virq_end,
        .set_affinity   = sun4v_virt_set_affinity,
};

void irq_install_pre_handler(int virt_irq,
                             void (*func)(unsigned int, void *, void *),
                             void *arg1, void *arg2)
{
        struct irq_handler_data *data = get_irq_chip_data(virt_irq);
        struct irq_chip *chip = get_irq_chip(virt_irq);

        if (WARN_ON(chip == &sun4v_irq || chip == &sun4v_virq)) {
                printk(KERN_ERR "IRQ: Trying to install pre-handler on "
                       "sun4v irq %u\n", virt_irq);
                return;
        }

        data->pre_handler = func;
        data->pre_handler_arg1 = arg1;
        data->pre_handler_arg2 = arg2;

        if (chip == &sun4u_irq_ack)
                return;

        set_irq_chip(virt_irq, &sun4u_irq_ack);
}

unsigned int build_irq(int inofixup, unsigned long iclr, unsigned long imap)
{
        struct ino_bucket *bucket;
        struct irq_handler_data *data;
        int ino;

        BUG_ON(tlb_type == hypervisor);

        ino = (upa_readq(imap) & (IMAP_IGN | IMAP_INO)) + inofixup;
        bucket = &ivector_table[ino];
        if (!bucket->virt_irq) {
                bucket->virt_irq = virt_irq_alloc(__irq(bucket));
                set_irq_chip(bucket->virt_irq, &sun4u_irq);
        }

        data = get_irq_chip_data(bucket->virt_irq);
        if (unlikely(data))
                goto out;

        data = kzalloc(sizeof(struct irq_handler_data), GFP_ATOMIC);
        if (unlikely(!data)) {
                prom_printf("IRQ: kzalloc(irq_handler_data) failed.\n");
                prom_halt();
        }
        set_irq_chip_data(bucket->virt_irq, data);

        data->imap  = imap;
        data->iclr  = iclr;

out:
        return bucket->virt_irq;
}

static unsigned int sun4v_build_common(unsigned long sysino,
                                       struct irq_chip *chip)
{
        struct ino_bucket *bucket;
        struct irq_handler_data *data;

        BUG_ON(tlb_type != hypervisor);

        bucket = &ivector_table[sysino];
        if (!bucket->virt_irq) {
                bucket->virt_irq = virt_irq_alloc(__irq(bucket));
                set_irq_chip(bucket->virt_irq, chip);
        }

        data = get_irq_chip_data(bucket->virt_irq);
        if (unlikely(data))
                goto out;

        data = kzalloc(sizeof(struct irq_handler_data), GFP_ATOMIC);
        if (unlikely(!data)) {
                prom_printf("IRQ: kzalloc(irq_handler_data) failed.\n");
                prom_halt();
        }
        set_irq_chip_data(bucket->virt_irq, data);

        /* Catch accidental accesses to these things.  IMAP/ICLR handling
         * is done by hypervisor calls on sun4v platforms, not by direct
         * register accesses.
         */
        data->imap = ~0UL;
        data->iclr = ~0UL;

out:
        return bucket->virt_irq;
}

unsigned int sun4v_build_irq(u32 devhandle, unsigned int devino)
{
        unsigned long sysino = sun4v_devino_to_sysino(devhandle, devino);

        return sun4v_build_common(sysino, &sun4v_irq);
}

unsigned int sun4v_build_virq(u32 devhandle, unsigned int devino)
{
        unsigned long sysino, hv_err;
        unsigned int virq;

        BUG_ON(devhandle & devino);

        sysino = devhandle | devino;
        BUG_ON(sysino & ~(IMAP_IGN | IMAP_INO));

        hv_err = sun4v_vintr_set_cookie(devhandle, devino, sysino);
        if (hv_err) {
                prom_printf("IRQ: Fatal, cannot set cookie for [%x:%x] "
                            "err=%lu\n", devhandle, devino, hv_err);
                prom_halt();
        }

        virq = sun4v_build_common(sysino, &sun4v_virq);

        virt_to_real_irq_table[virq].dev_handle = devhandle;
        virt_to_real_irq_table[virq].dev_ino = devino;

        return virq;
}

void ack_bad_irq(unsigned int virt_irq)
{
        struct ino_bucket *bucket = virt_irq_to_bucket(virt_irq);
        unsigned int ino = 0xdeadbeef;

        if (bucket)
                ino = bucket - &ivector_table[0];

        printk(KERN_CRIT "Unexpected IRQ from ino[%x] virt_irq[%u]\n",
               ino, virt_irq);
}

void handler_irq(int irq, struct pt_regs *regs)
{
        struct ino_bucket *bucket;
        struct pt_regs *old_regs;
        unsigned long pstate;

        clear_softint(1 << irq);

        old_regs = set_irq_regs(regs);
        irq_enter();

        /* Grab an atomic snapshot of the pending IVECs.  */
        __asm__ __volatile__("rdpr      %%pstate, %0\n\t"
                             "wrpr      %0, %3, %%pstate\n\t"
                             "ldx       [%2], %1\n\t"
                             "stx       %%g0, [%2]\n\t"
                             "wrpr      %0, 0x0, %%pstate\n\t"
                             : "=&r" (pstate), "=&r" (bucket)
                             : "r" (irq_work(smp_processor_id())),
                               "i" (PSTATE_IE)
                             : "memory");

        while (bucket) {
                struct ino_bucket *next = __bucket(bucket->irq_chain);

                bucket->irq_chain = 0UL;
                __do_IRQ(bucket->virt_irq);

                bucket = next;
        }

        irq_exit();
        set_irq_regs(old_regs);
}

#ifdef CONFIG_HOTPLUG_CPU
void fixup_irqs(void)
{
        unsigned int irq;

        for (irq = 0; irq < NR_IRQS; irq++) {
                unsigned long flags;

                spin_lock_irqsave(&irq_desc[irq].lock, flags);
                if (irq_desc[irq].action &&
                    !(irq_desc[irq].status & IRQ_PER_CPU)) {
                        if (irq_desc[irq].chip->set_affinity)
                                irq_desc[irq].chip->set_affinity(irq,
                                        irq_desc[irq].affinity);
                }
                spin_unlock_irqrestore(&irq_desc[irq].lock, flags);
        }
}
#endif

struct sun5_timer {
        u64     count0;
        u64     limit0;
        u64     count1;
        u64     limit1;
};

static struct sun5_timer *prom_timers;
static u64 prom_limit0, prom_limit1;

static void map_prom_timers(void)
{
        struct device_node *dp;
        const unsigned int *addr;

        /* PROM timer node hangs out in the top level of device siblings... */
        dp = of_find_node_by_path("/");
        dp = dp->child;
        while (dp) {
                if (!strcmp(dp->name, "counter-timer"))
                        break;
                dp = dp->sibling;
        }

        /* Assume if node is not present, PROM uses different tick mechanism
         * which we should not care about.
         */
        if (!dp) {
                prom_timers = (struct sun5_timer *) 0;
                return;
        }

        /* If PROM is really using this, it must be mapped by him. */
        addr = of_get_property(dp, "address", NULL);
        if (!addr) {
                prom_printf("PROM does not have timer mapped, trying to continue.\n");
                prom_timers = (struct sun5_timer *) 0;
                return;
        }
        prom_timers = (struct sun5_timer *) ((unsigned long)addr[0]);
}

static void kill_prom_timer(void)
{
        if (!prom_timers)
                return;

        /* Save them away for later. */
        prom_limit0 = prom_timers->limit0;
        prom_limit1 = prom_timers->limit1;

        /* Just as in sun4c/sun4m PROM uses timer which ticks at IRQ 14.
         * We turn both off here just to be paranoid.
         */
        prom_timers->limit0 = 0;
        prom_timers->limit1 = 0;

        /* Wheee, eat the interrupt packet too... */
        __asm__ __volatile__(
"       mov     0x40, %%g2\n"
"       ldxa    [%%g0] %0, %%g1\n"
"       ldxa    [%%g2] %1, %%g1\n"
"       stxa    %%g0, [%%g0] %0\n"
"       membar  #Sync\n"
        : /* no outputs */
        : "i" (ASI_INTR_RECEIVE), "i" (ASI_INTR_R)
        : "g1", "g2");
}

void init_irqwork_curcpu(void)
{
        int cpu = hard_smp_processor_id();

        trap_block[cpu].irq_worklist = 0UL;
}

/* Please be very careful with register_one_mondo() and
 * sun4v_register_mondo_queues().
 *
 * On SMP this gets invoked from the CPU trampoline before
 * the cpu has fully taken over the trap table from OBP,
 * and it's kernel stack + %g6 thread register state is
 * not fully cooked yet.
 *
 * Therefore you cannot make any OBP calls, not even prom_printf,
 * from these two routines.
 */
static void __cpuinit register_one_mondo(unsigned long paddr, unsigned long type, unsigned long qmask)
{
        unsigned long num_entries = (qmask + 1) / 64;
        unsigned long status;

        status = sun4v_cpu_qconf(type, paddr, num_entries);
        if (status != HV_EOK) {
                prom_printf("SUN4V: sun4v_cpu_qconf(%lu:%lx:%lu) failed, "
                            "err %lu\n", type, paddr, num_entries, status);
                prom_halt();
        }
}

void __cpuinit sun4v_register_mondo_queues(int this_cpu)
{
        struct trap_per_cpu *tb = &trap_block[this_cpu];

        register_one_mondo(tb->cpu_mondo_pa, HV_CPU_QUEUE_CPU_MONDO,
                           tb->cpu_mondo_qmask);
        register_one_mondo(tb->dev_mondo_pa, HV_CPU_QUEUE_DEVICE_MONDO,
                           tb->dev_mondo_qmask);
        register_one_mondo(tb->resum_mondo_pa, HV_CPU_QUEUE_RES_ERROR,
                           tb->resum_qmask);
        register_one_mondo(tb->nonresum_mondo_pa, HV_CPU_QUEUE_NONRES_ERROR,
                           tb->nonresum_qmask);
}

static void __init alloc_one_mondo(unsigned long *pa_ptr, unsigned long qmask)
{
        unsigned long size = PAGE_ALIGN(qmask + 1);
        void *p = __alloc_bootmem_low(size, size, 0);
        if (!p) {
                prom_printf("SUN4V: Error, cannot allocate mondo queue.\n");
                prom_halt();
        }

        *pa_ptr = __pa(p);
}

static void __init alloc_one_kbuf(unsigned long *pa_ptr, unsigned long qmask)
{
        unsigned long size = PAGE_ALIGN(qmask + 1);
        void *p = __alloc_bootmem_low(size, size, 0);

        if (!p) {
                prom_printf("SUN4V: Error, cannot allocate kbuf page.\n");
                prom_halt();
        }

        *pa_ptr = __pa(p);
}

static void __init init_cpu_send_mondo_info(struct trap_per_cpu *tb)
{
#ifdef CONFIG_SMP
        void *page;

        BUILD_BUG_ON((NR_CPUS * sizeof(u16)) > (PAGE_SIZE - 64));

        page = alloc_bootmem_low_pages(PAGE_SIZE);
        if (!page) {
                prom_printf("SUN4V: Error, cannot allocate cpu mondo page.\n");
                prom_halt();
        }

        tb->cpu_mondo_block_pa = __pa(page);
        tb->cpu_list_pa = __pa(page + 64);
#endif
}

/* Allocate mondo and error queues for all possible cpus.  */
static void __init sun4v_init_mondo_queues(void)
{
        int cpu;

        for_each_possible_cpu(cpu) {
                struct trap_per_cpu *tb = &trap_block[cpu];

                alloc_one_mondo(&tb->cpu_mondo_pa, tb->cpu_mondo_qmask);
                alloc_one_mondo(&tb->dev_mondo_pa, tb->dev_mondo_qmask);
                alloc_one_mondo(&tb->resum_mondo_pa, tb->resum_qmask);
                alloc_one_kbuf(&tb->resum_kernel_buf_pa, tb->resum_qmask);
                alloc_one_mondo(&tb->nonresum_mondo_pa, tb->nonresum_qmask);
                alloc_one_kbuf(&tb->nonresum_kernel_buf_pa,
                               tb->nonresum_qmask);

                init_cpu_send_mondo_info(tb);
        }

        /* Load up the boot cpu's entries.  */
        sun4v_register_mondo_queues(hard_smp_processor_id());
}

static struct irqaction timer_irq_action = {
        .name = "timer",
};

/* Only invoked on boot processor. */
void __init init_IRQ(void)
{
        map_prom_timers();
        kill_prom_timer();
        memset(&ivector_table[0], 0, sizeof(ivector_table));

        if (tlb_type == hypervisor)
                sun4v_init_mondo_queues();

        /* We need to clear any IRQ's pending in the soft interrupt
         * registers, a spurious one could be left around from the
         * PROM timer which we just disabled.
         */
        clear_softint(get_softint());

        /* Now that ivector table is initialized, it is safe
         * to receive IRQ vector traps.  We will normally take
         * one or two right now, in case some device PROM used
         * to boot us wants to speak to us.  We just ignore them.
         */
        __asm__ __volatile__("rdpr      %%pstate, %%g1\n\t"
                             "or        %%g1, %0, %%g1\n\t"
                             "wrpr      %%g1, 0x0, %%pstate"
                             : /* No outputs */
                             : "i" (PSTATE_IE)
                             : "g1");

        irq_desc[0].action = &timer_irq_action;
}