Linux 2.6.13-rc4

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

/* $Id: irq.c,v 1.114 2002/01/11 08:45:38 davem Exp $
 * irq.c: UltraSparc IRQ handling/init/registry.
 *
 * Copyright (C) 1997  David S. Miller  (davem@caip.rutgers.edu)
 * Copyright (C) 1998  Eddie C. Dost    (ecd@skynet.be)
 * Copyright (C) 1998  Jakub Jelinek    (jj@ultra.linux.cz)
 */

#include <linux/config.h>
#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 <asm/ptrace.h>
#include <asm/processor.h>
#include <asm/atomic.h>
#include <asm/system.h>
#include <asm/irq.h>
#include <asm/sbus.h>
#include <asm/iommu.h>
#include <asm/upa.h>
#include <asm/oplib.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>

#ifdef CONFIG_SMP
static void distribute_irqs(void);
#endif

/* 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.
 */

struct ino_bucket ivector_table[NUM_IVECS] __attribute__ ((aligned (SMP_CACHE_BYTES)));

/* 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.
 */
struct irq_work_struct {
        unsigned int    irq_worklists[16];
};
struct irq_work_struct __irq_work[NR_CPUS];
#define irq_work(__cpu, __pil)  &(__irq_work[(__cpu)].irq_worklists[(__pil)])

static struct irqaction *irq_action[NR_IRQS+1];

/* This only synchronizes entities which modify IRQ handler
 * state and some selected user-level spots that want to
 * read things in the table.  IRQ handler processing orders
 * its' accesses such that no locking is needed.
 */
static DEFINE_SPINLOCK(irq_action_lock);

static void register_irq_proc (unsigned int irq);

/*
 * Upper 2b of irqaction->flags holds the ino.
 * irqaction->mask holds the smp affinity information.
 */
#define put_ino_in_irqaction(action, irq) \
        action->flags &= 0xffffffffffffUL; \
        if (__bucket(irq) == &pil0_dummy_bucket) \
                action->flags |= 0xdeadUL << 48;  \
        else \
                action->flags |= __irq_ino(irq) << 48;
#define get_ino_in_irqaction(action)    (action->flags >> 48)

#define put_smpaff_in_irqaction(action, smpaff) (action)->mask = (smpaff)
#define get_smpaff_in_irqaction(action)         ((action)->mask)

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

        spin_lock_irqsave(&irq_action_lock, flags);
        if (i <= NR_IRQS) {
                if (!(action = *(i + irq_action)))
                        goto out_unlock;
                seq_printf(p, "%3d: ", i);
#ifndef CONFIG_SMP
                seq_printf(p, "%10u ", kstat_irqs(i));
#else
                for (j = 0; j < NR_CPUS; j++) {
                        if (!cpu_online(j))
                                continue;
                        seq_printf(p, "%10u ",
                                   kstat_cpu(j).irqs[i]);
                }
#endif
                seq_printf(p, " %s:%lx", action->name,
                           get_ino_in_irqaction(action));
                for (action = action->next; action; action = action->next) {
                        seq_printf(p, ", %s:%lx", action->name,
                                   get_ino_in_irqaction(action));
                }
                seq_putc(p, '\n');
        }
out_unlock:
        spin_unlock_irqrestore(&irq_action_lock, flags);

        return 0;
}

/* Now these are always passed a true fully specified sun4u INO. */
void enable_irq(unsigned int irq)
{
        struct ino_bucket *bucket = __bucket(irq);
        unsigned long imap;
        unsigned long tid;

        imap = bucket->imap;
        if (imap == 0UL)
                return;

        preempt_disable();

        if (tlb_type == cheetah || tlb_type == cheetah_plus) {
                unsigned long ver;

                __asm__ ("rdpr %%ver, %0" : "=r" (ver));
                if ((ver >> 32) == 0x003e0016) {
                        /* We set it to our JBUS ID. */
                        __asm__ __volatile__("ldxa [%%g0] %1, %0"
                                             : "=r" (tid)
                                             : "i" (ASI_JBUS_CONFIG));
                        tid = ((tid & (0x1fUL<<17)) << 9);
                        tid &= IMAP_TID_JBUS;
                } else {
                        /* We set it to our Safari AID. */
                        __asm__ __volatile__("ldxa [%%g0] %1, %0"
                                             : "=r" (tid)
                                             : "i" (ASI_SAFARI_CONFIG));
                        tid = ((tid & (0x3ffUL<<17)) << 9);
                        tid &= IMAP_AID_SAFARI;
                }
        } else if (this_is_starfire == 0) {
                /* We set it to our UPA MID. */
                __asm__ __volatile__("ldxa [%%g0] %1, %0"
                                     : "=r" (tid)
                                     : "i" (ASI_UPA_CONFIG));
                tid = ((tid & UPA_CONFIG_MID) << 9);
                tid &= IMAP_TID_UPA;
        } else {
                tid = (starfire_translate(imap, smp_processor_id()) << 26);
                tid &= IMAP_TID_UPA;
        }

        /* NOTE NOTE NOTE, IGN and INO are read-only, IGN is a product
         * of this SYSIO's preconfigured IGN in the SYSIO Control
         * Register, the hardware just mirrors that value here.
         * However for Graphics and UPA Slave devices the full
         * IMAP_INR field can be set by the programmer here.
         *
         * Things like FFB can now be handled via the new IRQ mechanism.
         */
        upa_writel(tid | IMAP_VALID, imap);

        preempt_enable();
}

/* This now gets passed true ino's as well. */
void disable_irq(unsigned int irq)
{
        struct ino_bucket *bucket = __bucket(irq);
        unsigned long imap;

        imap = bucket->imap;
        if (imap != 0UL) {
                u32 tmp;

                /* NOTE: We do not want to futz with the IRQ clear registers
                 *       and move the state to IDLE, the SCSI code does call
                 *       disable_irq() to assure atomicity in the queue cmd
                 *       SCSI adapter driver code.  Thus we'd lose interrupts.
                 */
                tmp = upa_readl(imap);
                tmp &= ~IMAP_VALID;
                upa_writel(tmp, imap);
        }
}

/* The timer is the one "weird" interrupt which is generated by
 * the CPU %tick register and not by some normal vectored interrupt
 * source.  To handle this special case, we use this dummy INO bucket.
 */
static struct irq_desc pil0_dummy_desc;
static struct ino_bucket pil0_dummy_bucket = {
        .irq_info       =       &pil0_dummy_desc,
};

static void build_irq_error(const char *msg, unsigned int ino, int pil, int inofixup,
                            unsigned long iclr, unsigned long imap,
                            struct ino_bucket *bucket)
{
        prom_printf("IRQ: INO %04x (%d:%016lx:%016lx) --> "
                    "(%d:%d:%016lx:%016lx), halting...\n",
                    ino, bucket->pil, bucket->iclr, bucket->imap,
                    pil, inofixup, iclr, imap);
        prom_halt();
}

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

        if (pil == 0) {
                if (iclr != 0UL || imap != 0UL) {
                        prom_printf("Invalid dummy bucket for PIL0 (%lx:%lx)\n",
                                    iclr, imap);
                        prom_halt();
                }
                return __irq(&pil0_dummy_bucket);
        }

        /* RULE: Both must be specified in all other cases. */
        if (iclr == 0UL || imap == 0UL) {
                prom_printf("Invalid build_irq %d %d %016lx %016lx\n",
                            pil, inofixup, iclr, imap);
                prom_halt();
        }
        
        ino = (upa_readl(imap) & (IMAP_IGN | IMAP_INO)) + inofixup;
        if (ino > NUM_IVECS) {
                prom_printf("Invalid INO %04x (%d:%d:%016lx:%016lx)\n",
                            ino, pil, inofixup, iclr, imap);
                prom_halt();
        }

        bucket = &ivector_table[ino];
        if (bucket->flags & IBF_ACTIVE)
                build_irq_error("IRQ: Trying to build active INO bucket.\n",
                                ino, pil, inofixup, iclr, imap, bucket);

        if (bucket->irq_info) {
                if (bucket->imap != imap || bucket->iclr != iclr)
                        build_irq_error("IRQ: Trying to reinit INO bucket.\n",
                                        ino, pil, inofixup, iclr, imap, bucket);

                goto out;
        }

        bucket->irq_info = kmalloc(sizeof(struct irq_desc), GFP_ATOMIC);
        if (!bucket->irq_info) {
                prom_printf("IRQ: Error, kmalloc(irq_desc) failed.\n");
                prom_halt();
        }
        memset(bucket->irq_info, 0, sizeof(struct irq_desc));

        /* Ok, looks good, set it up.  Don't touch the irq_chain or
         * the pending flag.
         */
        bucket->imap  = imap;
        bucket->iclr  = iclr;
        bucket->pil   = pil;
        bucket->flags = 0;

out:
        return __irq(bucket);
}

static void atomic_bucket_insert(struct ino_bucket *bucket)
{
        unsigned long pstate;
        unsigned int *ent;

        __asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));
        __asm__ __volatile__("wrpr %0, %1, %%pstate"
                             : : "r" (pstate), "i" (PSTATE_IE));
        ent = irq_work(smp_processor_id(), bucket->pil);
        bucket->irq_chain = *ent;
        *ent = __irq(bucket);
        __asm__ __volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate));
}

static int check_irq_sharing(int pil, unsigned long irqflags)
{
        struct irqaction *action, *tmp;

        action = *(irq_action + pil);
        if (action) {
                if ((action->flags & SA_SHIRQ) && (irqflags & SA_SHIRQ)) {
                        for (tmp = action; tmp->next; tmp = tmp->next)
                                ;
                } else {
                        return -EBUSY;
                }
        }
        return 0;
}

static void append_irq_action(int pil, struct irqaction *action)
{
        struct irqaction **pp = irq_action + pil;

        while (*pp)
                pp = &((*pp)->next);
        *pp = action;
}

static struct irqaction *get_action_slot(struct ino_bucket *bucket)
{
        struct irq_desc *desc = bucket->irq_info;
        int max_irq, i;

        max_irq = 1;
        if (bucket->flags & IBF_PCI)
                max_irq = MAX_IRQ_DESC_ACTION;
        for (i = 0; i < max_irq; i++) {
                struct irqaction *p = &desc->action[i];
                u32 mask = (1 << i);

                if (desc->action_active_mask & mask)
                        continue;

                desc->action_active_mask |= mask;
                return p;
        }
        return NULL;
}

int request_irq(unsigned int irq, irqreturn_t (*handler)(int, void *, struct pt_regs *),
                unsigned long irqflags, const char *name, void *dev_id)
{
        struct irqaction *action;
        struct ino_bucket *bucket = __bucket(irq);
        unsigned long flags;
        int pending = 0;

        if (unlikely(!handler))
                return -EINVAL;

        if (unlikely(!bucket->irq_info))
                return -ENODEV;

        if ((bucket != &pil0_dummy_bucket) && (irqflags & SA_SAMPLE_RANDOM)) {
                /*
                 * This function might sleep, we want to call it first,
                 * outside of the atomic block. In SA_STATIC_ALLOC case,
                 * random driver's kmalloc will fail, but it is safe.
                 * If already initialized, random driver will not reinit.
                 * Yes, this might clear the entropy pool if the wrong
                 * driver is attempted to be loaded, without actually
                 * installing a new handler, but is this really a problem,
                 * only the sysadmin is able to do this.
                 */
                rand_initialize_irq(irq);
        }

        spin_lock_irqsave(&irq_action_lock, flags);

        if (check_irq_sharing(bucket->pil, irqflags)) {
                spin_unlock_irqrestore(&irq_action_lock, flags);
                return -EBUSY;
        }

        action = get_action_slot(bucket);
        if (!action) { 
                spin_unlock_irqrestore(&irq_action_lock, flags);
                return -ENOMEM;
        }

        bucket->flags |= IBF_ACTIVE;
        pending = 0;
        if (bucket != &pil0_dummy_bucket) {
                pending = bucket->pending;
                if (pending)
                        bucket->pending = 0;
        }

        action->handler = handler;
        action->flags = irqflags;
        action->name = name;
        action->next = NULL;
        action->dev_id = dev_id;
        put_ino_in_irqaction(action, irq);
        put_smpaff_in_irqaction(action, CPU_MASK_NONE);

        append_irq_action(bucket->pil, action);

        enable_irq(irq);

        /* We ate the IVEC already, this makes sure it does not get lost. */
        if (pending) {
                atomic_bucket_insert(bucket);
                set_softint(1 << bucket->pil);
        }

        spin_unlock_irqrestore(&irq_action_lock, flags);

        if (bucket != &pil0_dummy_bucket)
                register_irq_proc(__irq_ino(irq));

#ifdef CONFIG_SMP
        distribute_irqs();
#endif
        return 0;
}

EXPORT_SYMBOL(request_irq);

static struct irqaction *unlink_irq_action(unsigned int irq, void *dev_id)
{
        struct ino_bucket *bucket = __bucket(irq);
        struct irqaction *action, **pp;

        pp = irq_action + bucket->pil;
        action = *pp;
        if (unlikely(!action))
                return NULL;

        if (unlikely(!action->handler)) {
                printk("Freeing free IRQ %d\n", bucket->pil);
                return NULL;
        }

        while (action && action->dev_id != dev_id) {
                pp = &action->next;
                action = *pp;
        }

        if (likely(action))
                *pp = action->next;

        return action;
}

void free_irq(unsigned int irq, void *dev_id)
{
        struct irqaction *action;
        struct ino_bucket *bucket;
        unsigned long flags;

        spin_lock_irqsave(&irq_action_lock, flags);

        action = unlink_irq_action(irq, dev_id);

        spin_unlock_irqrestore(&irq_action_lock, flags);

        if (unlikely(!action))
                return;

        synchronize_irq(irq);

        spin_lock_irqsave(&irq_action_lock, flags);

        bucket = __bucket(irq);
        if (bucket != &pil0_dummy_bucket) {
                struct irq_desc *desc = bucket->irq_info;
                unsigned long imap = bucket->imap;
                int ent, i;

                for (i = 0; i < MAX_IRQ_DESC_ACTION; i++) {
                        struct irqaction *p = &desc->action[i];

                        if (p == action) {
                                desc->action_active_mask &= ~(1 << i);
                                break;
                        }
                }

                if (!desc->action_active_mask) {
                        /* This unique interrupt source is now inactive. */
                        bucket->flags &= ~IBF_ACTIVE;

                        /* See if any other buckets share this bucket's IMAP
                         * and are still active.
                         */
                        for (ent = 0; ent < NUM_IVECS; ent++) {
                                struct ino_bucket *bp = &ivector_table[ent];
                                if (bp != bucket        &&
                                    bp->imap == imap    &&
                                    (bp->flags & IBF_ACTIVE) != 0)
                                        break;
                        }

                        /* Only disable when no other sub-irq levels of
                         * the same IMAP are active.
                         */
                        if (ent == NUM_IVECS)
                                disable_irq(irq);
                }
        }

        spin_unlock_irqrestore(&irq_action_lock, flags);
}

EXPORT_SYMBOL(free_irq);

#ifdef CONFIG_SMP
void synchronize_irq(unsigned int irq)
{
        struct ino_bucket *bucket = __bucket(irq);

#if 0
        /* The following is how I wish I could implement this.
         * Unfortunately the ICLR registers are read-only, you can
         * only write ICLR_foo values to them.  To get the current
         * IRQ status you would need to get at the IRQ diag registers
         * in the PCI/SBUS controller and the layout of those vary
         * from one controller to the next, sigh... -DaveM
         */
        unsigned long iclr = bucket->iclr;

        while (1) {
                u32 tmp = upa_readl(iclr);
                
                if (tmp == ICLR_TRANSMIT ||
                    tmp == ICLR_PENDING) {
                        cpu_relax();
                        continue;
                }
                break;
        }
#else
        /* So we have to do this with a INPROGRESS bit just like x86.  */
        while (bucket->flags & IBF_INPROGRESS)
                cpu_relax();
#endif
}
#endif /* CONFIG_SMP */

static void process_bucket(int irq, struct ino_bucket *bp, struct pt_regs *regs)
{
        struct irq_desc *desc = bp->irq_info;
        unsigned char flags = bp->flags;
        u32 action_mask, i;
        int random;

        bp->flags |= IBF_INPROGRESS;

        if (unlikely(!(flags & IBF_ACTIVE))) {
                bp->pending = 1;
                goto out;
        }

        if (desc->pre_handler)
                desc->pre_handler(bp,
                                  desc->pre_handler_arg1,
                                  desc->pre_handler_arg2);

        action_mask = desc->action_active_mask;
        random = 0;
        for (i = 0; i < MAX_IRQ_DESC_ACTION; i++) {
                struct irqaction *p = &desc->action[i];
                u32 mask = (1 << i);

                if (!(action_mask & mask))
                        continue;

                action_mask &= ~mask;

                if (p->handler(__irq(bp), p->dev_id, regs) == IRQ_HANDLED)
                        random |= p->flags;

                if (!action_mask)
                        break;
        }
        if (bp->pil != 0) {
                upa_writel(ICLR_IDLE, bp->iclr);
                /* Test and add entropy */
                if (random & SA_SAMPLE_RANDOM)
                        add_interrupt_randomness(irq);
        }
out:
        bp->flags &= ~IBF_INPROGRESS;
}

void handler_irq(int irq, struct pt_regs *regs)
{
        struct ino_bucket *bp;
        int cpu = smp_processor_id();

#ifndef CONFIG_SMP
        /*
         * Check for TICK_INT on level 14 softint.
         */
        {
                unsigned long clr_mask = 1 << irq;
                unsigned long tick_mask = tick_ops->softint_mask;

                if ((irq == 14) && (get_softint() & tick_mask)) {
                        irq = 0;
                        clr_mask = tick_mask;
                }
                clear_softint(clr_mask);
        }
#else
        clear_softint(1 << irq);
#endif

        irq_enter();
        kstat_this_cpu.irqs[irq]++;

        /* Sliiiick... */
#ifndef CONFIG_SMP
        bp = ((irq != 0) ?
              __bucket(xchg32(irq_work(cpu, irq), 0)) :
              &pil0_dummy_bucket);
#else
        bp = __bucket(xchg32(irq_work(cpu, irq), 0));
#endif
        while (bp) {
                struct ino_bucket *nbp = __bucket(bp->irq_chain);

                bp->irq_chain = 0;
                process_bucket(irq, bp, regs);
                bp = nbp;
        }
        irq_exit();
}

#ifdef CONFIG_BLK_DEV_FD
extern irqreturn_t floppy_interrupt(int, void *, struct pt_regs *);;

/* XXX No easy way to include asm/floppy.h XXX */
extern unsigned char *pdma_vaddr;
extern unsigned long pdma_size;
extern volatile int doing_pdma;
extern unsigned long fdc_status;

irqreturn_t sparc_floppy_irq(int irq, void *dev_cookie, struct pt_regs *regs)
{
        if (likely(doing_pdma)) {
                void __iomem *stat = (void __iomem *) fdc_status;
                unsigned char *vaddr = pdma_vaddr;
                unsigned long size = pdma_size;
                u8 val;

                while (size) {
                        val = readb(stat);
                        if (unlikely(!(val & 0x80))) {
                                pdma_vaddr = vaddr;
                                pdma_size = size;
                                return IRQ_HANDLED;
                        }
                        if (unlikely(!(val & 0x20))) {
                                pdma_vaddr = vaddr;
                                pdma_size = size;
                                doing_pdma = 0;
                                goto main_interrupt;
                        }
                        if (val & 0x40) {
                                /* read */
                                *vaddr++ = readb(stat + 1);
                        } else {
                                unsigned char data = *vaddr++;

                                /* write */
                                writeb(data, stat + 1);
                        }
                        size--;
                }

                pdma_vaddr = vaddr;
                pdma_size = size;

                /* Send Terminal Count pulse to floppy controller. */
                val = readb(auxio_register);
                val |= AUXIO_AUX1_FTCNT;
                writeb(val, auxio_register);
                val &= AUXIO_AUX1_FTCNT;
                writeb(val, auxio_register);

                doing_pdma = 0;
        }

main_interrupt:
        return floppy_interrupt(irq, dev_cookie, regs);
}
EXPORT_SYMBOL(sparc_floppy_irq);
#endif

/* We really don't need these at all on the Sparc.  We only have
 * stubs here because they are exported to modules.
 */
unsigned long probe_irq_on(void)
{
        return 0;
}

EXPORT_SYMBOL(probe_irq_on);

int probe_irq_off(unsigned long mask)
{
        return 0;
}

EXPORT_SYMBOL(probe_irq_off);

#ifdef CONFIG_SMP
static int retarget_one_irq(struct irqaction *p, int goal_cpu)
{
        struct ino_bucket *bucket = get_ino_in_irqaction(p) + ivector_table;
        unsigned long imap = bucket->imap;
        unsigned int tid;

        while (!cpu_online(goal_cpu)) {
                if (++goal_cpu >= NR_CPUS)
                        goal_cpu = 0;
        }

        if (tlb_type == cheetah || tlb_type == cheetah_plus) {
                tid = goal_cpu << 26;
                tid &= IMAP_AID_SAFARI;
        } else if (this_is_starfire == 0) {
                tid = goal_cpu << 26;
                tid &= IMAP_TID_UPA;
        } else {
                tid = (starfire_translate(imap, goal_cpu) << 26);
                tid &= IMAP_TID_UPA;
        }
        upa_writel(tid | IMAP_VALID, imap);

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

        return goal_cpu;
}

/* Called from request_irq. */
static void distribute_irqs(void)
{
        unsigned long flags;
        int cpu, level;

        spin_lock_irqsave(&irq_action_lock, flags);
        cpu = 0;

        /*
         * Skip the timer at [0], and very rare error/power intrs at [15].
         * Also level [12], it causes problems on Ex000 systems.
         */
        for (level = 1; level < NR_IRQS; level++) {
                struct irqaction *p = irq_action[level];

                if (level == 12)
                        continue;

                while(p) {
                        cpu = retarget_one_irq(p, cpu);
                        p = p->next;
                }
        }
        spin_unlock_irqrestore(&irq_action_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)
{
        unsigned int addr[3];
        int tnode, err;

        /* PROM timer node hangs out in the top level of device siblings... */
        tnode = prom_finddevice("/counter-timer");

        /* Assume if node is not present, PROM uses different tick mechanism
         * which we should not care about.
         */
        if (tnode == 0 || tnode == -1) {
                prom_timers = (struct sun5_timer *) 0;
                return;
        }

        /* If PROM is really using this, it must be mapped by him. */
        err = prom_getproperty(tnode, "address", (char *)addr, sizeof(addr));
        if (err == -1) {
                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)
{
        register struct irq_work_struct *workp asm("o2");
        register unsigned long tmp asm("o3");
        int cpu = hard_smp_processor_id();

        memset(__irq_work + cpu, 0, sizeof(*workp));

        /* Make sure we are called with PSTATE_IE disabled.  */
        __asm__ __volatile__("rdpr      %%pstate, %0\n\t"
                             : "=r" (tmp));
        if (tmp & PSTATE_IE) {
                prom_printf("BUG: init_irqwork_curcpu() called with "
                            "PSTATE_IE enabled, bailing.\n");
                __asm__ __volatile__("mov       %%i7, %0\n\t"
                                     : "=r" (tmp));
                prom_printf("BUG: Called from %lx\n", tmp);
                prom_halt();
        }

        /* Set interrupt globals.  */
        workp = &__irq_work[cpu];
        __asm__ __volatile__(
        "rdpr   %%pstate, %0\n\t"
        "wrpr   %0, %1, %%pstate\n\t"
        "mov    %2, %%g6\n\t"
        "wrpr   %0, 0x0, %%pstate\n\t"
        : "=&r" (tmp)
        : "i" (PSTATE_IG), "r" (workp));
}

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

        /* 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");
}

static struct proc_dir_entry * root_irq_dir;
static struct proc_dir_entry * irq_dir [NUM_IVECS];

#ifdef CONFIG_SMP

static int irq_affinity_read_proc (char *page, char **start, off_t off,
                        int count, int *eof, void *data)
{
        struct ino_bucket *bp = ivector_table + (long)data;
        struct irq_desc *desc = bp->irq_info;
        struct irqaction *ap = desc->action;
        cpumask_t mask;
        int len;

        mask = get_smpaff_in_irqaction(ap);
        if (cpus_empty(mask))
                mask = cpu_online_map;

        len = cpumask_scnprintf(page, count, mask);
        if (count - len < 2)
                return -EINVAL;
        len += sprintf(page + len, "\n");
        return len;
}

static inline void set_intr_affinity(int irq, cpumask_t hw_aff)
{
        struct ino_bucket *bp = ivector_table + irq;
        struct irq_desc *desc = bp->irq_info;
        struct irqaction *ap = desc->action;

        /* Users specify affinity in terms of hw cpu ids.
         * As soon as we do this, handler_irq() might see and take action.
         */
        put_smpaff_in_irqaction(ap, hw_aff);

        /* Migration is simply done by the next cpu to service this
         * interrupt.
         */
}

static int irq_affinity_write_proc (struct file *file, const char __user *buffer,
                                        unsigned long count, void *data)
{
        int irq = (long) data, full_count = count, err;
        cpumask_t new_value;

        err = cpumask_parse(buffer, count, new_value);

        /*
         * Do not allow disabling IRQs completely - it's a too easy
         * way to make the system unusable accidentally :-) At least
         * one online CPU still has to be targeted.
         */
        cpus_and(new_value, new_value, cpu_online_map);
        if (cpus_empty(new_value))
                return -EINVAL;

        set_intr_affinity(irq, new_value);

        return full_count;
}

#endif

#define MAX_NAMELEN 10

static void register_irq_proc (unsigned int irq)
{
        char name [MAX_NAMELEN];

        if (!root_irq_dir || irq_dir[irq])
                return;

        memset(name, 0, MAX_NAMELEN);
        sprintf(name, "%x", irq);

        /* create /proc/irq/1234 */
        irq_dir[irq] = proc_mkdir(name, root_irq_dir);

#ifdef CONFIG_SMP
        /* XXX SMP affinity not supported on starfire yet. */
        if (this_is_starfire == 0) {
                struct proc_dir_entry *entry;

                /* create /proc/irq/1234/smp_affinity */
                entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);

                if (entry) {
                        entry->nlink = 1;
                        entry->data = (void *)(long)irq;
                        entry->read_proc = irq_affinity_read_proc;
                        entry->write_proc = irq_affinity_write_proc;
                }
        }
#endif
}

void init_irq_proc (void)
{
        /* create /proc/irq */
        root_irq_dir = proc_mkdir("irq", NULL);
}