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[davej-history.git] / arch / sparc64 / kernel / irq.c

/* $Id: irq.c,v 1.92 2000/08/26 02:42:28 anton 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/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/malloc.h>
#include <linux/random.h> /* XXX ADD add_foo_randomness() calls... -DaveM */
#include <linux/init.h>
#include <linux/delay.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/hardirq.h>
#include <asm/softirq.h>

/* Internal flag, should not be visible elsewhere at all. */
#define SA_IMAP_MASKED          0x100
#define SA_DMA_SYNC             0x200

#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 (64)));

#ifndef CONFIG_SMP
unsigned int __up_workvec[16] __attribute__ ((aligned (64)));
#define irq_work(__cpu, __pil)  &(__up_workvec[(void)(__cpu), (__pil)])
#else
#define irq_work(__cpu, __pil)  &(cpu_data[(__cpu)].irq_worklists[(__pil)])
#endif

#ifdef CONFIG_PCI
/* This is a table of physical addresses used to deal with SA_DMA_SYNC.
 * It is used for PCI only to synchronize DMA transfers with IRQ delivery
 * for devices behind busses other than APB on Sabre systems.
 *
 * Currently these physical addresses are just config space accesses
 * to the command register for that device.
 */
unsigned long pci_dma_wsync;
unsigned long dma_sync_reg_table[256];
unsigned char dma_sync_reg_table_entry = 0;
#endif

/* This is based upon code in the 32-bit Sparc kernel written mostly by
 * David Redman (djhr@tadpole.co.uk).
 */
#define MAX_STATIC_ALLOC        4
static struct irqaction static_irqaction[MAX_STATIC_ALLOC];
static int static_irq_count = 0;

/* This is exported so that fast IRQ handlers can get at it... -DaveM */
struct irqaction *irq_action[NR_IRQS+1] = {
          NULL, NULL, NULL, NULL, NULL, NULL , NULL, NULL,
          NULL, NULL, NULL, NULL, NULL, NULL , NULL, NULL
};

int get_irq_list(char *buf)
{
        int i, len = 0;
        struct irqaction *action;
#ifdef CONFIG_SMP
        int j;
#endif

        for(i = 0; i < (NR_IRQS + 1); i++) {
                if(!(action = *(i + irq_action)))
                        continue;
                len += sprintf(buf + len, "%3d: ", i);
#ifndef CONFIG_SMP
                len += sprintf(buf + len, "%10u ", kstat_irqs(i));
#else
                for (j = 0; j < smp_num_cpus; j++)
                        len += sprintf(buf + len, "%10u ",
                                       kstat.irqs[cpu_logical_map(j)][i]);
#endif
                len += sprintf(buf + len, "%c %s",
                               (action->flags & SA_INTERRUPT) ? '+' : ' ',
                               action->name);
                for(action = action->next; action; action = action->next) {
                        len += sprintf(buf+len, ",%s %s",
                                       (action->flags & SA_INTERRUPT) ? " +" : "",
                                       action->name);
                }
                len += sprintf(buf + len, "\n");
        }
        return len;
}

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

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

        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);
        } else {
                extern unsigned int starfire_translate(unsigned long imap,
                                                       unsigned int upaid);

                tid = (starfire_translate(imap, current->processor) << 26);
        }

        /* 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(IMAP_VALID | (tid & IMAP_TID), imap);
}

/* 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 ino_bucket pil0_dummy_bucket = {
        0,      /* irq_chain */
        0,      /* pil */
        0,      /* pending */
        0,      /* flags */
        0,      /* __unused */
        NULL,   /* irq_info */
        0UL,    /* iclr */
        0UL,    /* imap */
};

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();
        }

        /* Ok, looks good, set it up.  Don't touch the irq_chain or
         * the pending flag.
         */
        bucket = &ivector_table[ino];
        if ((bucket->flags & IBF_ACTIVE) ||
            (bucket->irq_info != NULL)) {
                /* This is a gross fatal error if it happens here. */
                prom_printf("IRQ: Trying to reinit INO bucket, fatal error.\n");
                prom_printf("IRQ: Request INO %04x (%d:%d:%016lx:%016lx)\n",
                            ino, pil, inofixup, iclr, imap);
                prom_printf("IRQ: Existing (%d:%016lx:%016lx)\n",
                            bucket->pil, bucket->iclr, bucket->imap);
                prom_printf("IRQ: Cannot continue, halting...\n");
                prom_halt();
        }
        bucket->imap  = imap;
        bucket->iclr  = iclr;
        bucket->pil   = pil;
        bucket->flags = 0;

        bucket->irq_info = NULL;

        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));
}

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

        if ((bucket != &pil0_dummy_bucket) &&
            (bucket < &ivector_table[0] ||
             bucket >= &ivector_table[NUM_IVECS])) {
                unsigned int *caller;

                __asm__ __volatile__("mov %%i7, %0" : "=r" (caller));
                printk(KERN_CRIT "request_irq: Old style IRQ registry attempt "
                       "from %p, irq %08x.\n", caller, irq);
                return -EINVAL;
        }       
        if(!handler)
            return -EINVAL;

        if (!bucket->pil)
                irqflags &= ~SA_IMAP_MASKED;
        else {
                irqflags |= SA_IMAP_MASKED;
                if (bucket->flags & IBF_PCI) {
                        /*
                         * PCI IRQs should never use SA_INTERRUPT.
                         */
                        irqflags &= ~(SA_INTERRUPT);

                        /*
                         * Check wether we _should_ use DMA Write Sync
                         * (for devices behind bridges behind APB). 
                         */
                        if (bucket->flags & IBF_DMA_SYNC)
                                irqflags |= SA_DMA_SYNC;
                }
        }

        save_and_cli(flags);

        action = *(bucket->pil + irq_action);
        if(action) {
                if((action->flags & SA_SHIRQ) && (irqflags & SA_SHIRQ))
                        for (tmp = action; tmp->next; tmp = tmp->next)
                                ;
                else {
                        restore_flags(flags);
                        return -EBUSY;
                }
                if((action->flags & SA_INTERRUPT) ^ (irqflags & SA_INTERRUPT)) {
                        printk("Attempt to mix fast and slow interrupts on IRQ%d "
                               "denied\n", bucket->pil);
                        restore_flags(flags);
                        return -EBUSY;
                }   
                action = NULL;          /* Or else! */
        }

        /* If this is flagged as statically allocated then we use our
         * private struct which is never freed.
         */
        if(irqflags & SA_STATIC_ALLOC) {
            if(static_irq_count < MAX_STATIC_ALLOC)
                action = &static_irqaction[static_irq_count++];
            else
                printk("Request for IRQ%d (%s) SA_STATIC_ALLOC failed "
                       "using kmalloc\n", irq, name);
        }       
        if(action == NULL)
            action = (struct irqaction *)kmalloc(sizeof(struct irqaction),
                                                 GFP_KERNEL);
        
        if(!action) { 
                restore_flags(flags);
                return -ENOMEM;
        }

        if ((irqflags & SA_IMAP_MASKED) == 0) {
                bucket->irq_info = action;
                bucket->flags |= IBF_ACTIVE;
        } else {
                if((bucket->flags & IBF_ACTIVE) != 0) {
                        void *orig = bucket->irq_info;
                        void **vector = NULL;

                        if((bucket->flags & IBF_PCI) == 0) {
                                printk("IRQ: Trying to share non-PCI bucket.\n");
                                goto free_and_ebusy;
                        }
                        if((bucket->flags & IBF_MULTI) == 0) {
                                vector = kmalloc(sizeof(void *) * 4, GFP_KERNEL);
                                if(vector == NULL)
                                        goto free_and_enomem;

                                /* We might have slept. */
                                if ((bucket->flags & IBF_MULTI) != 0) {
                                        int ent;

                                        kfree(vector);
                                        vector = (void **)bucket->irq_info;
                                        for(ent = 0; ent < 4; ent++) {
                                                if (vector[ent] == NULL) {
                                                        vector[ent] = action;
                                                        break;
                                                }
                                        }
                                        if (ent == 4)
                                                goto free_and_ebusy;
                                } else {
                                        vector[0] = orig;
                                        vector[1] = action;
                                        vector[2] = NULL;
                                        vector[3] = NULL;
                                        bucket->irq_info = vector;
                                        bucket->flags |= IBF_MULTI;
                                }
                        } else {
                                int ent;

                                vector = (void **)orig;
                                for(ent = 0; ent < 4; ent++) {
                                        if(vector[ent] == NULL) {
                                                vector[ent] = action;
                                                break;
                                        }
                                }
                                if (ent == 4)
                                        goto free_and_ebusy;
                        }
                } else {
                        bucket->irq_info = action;
                        bucket->flags |= IBF_ACTIVE;
                }
                pending = bucket->pending;
                if(pending)
                        bucket->pending = 0;
        }

        action->mask = (unsigned long) bucket;
        action->handler = handler;
        action->flags = irqflags;
        action->name = name;
        action->next = NULL;
        action->dev_id = dev_id;

        if(tmp)
                tmp->next = action;
        else
                *(bucket->pil + irq_action) = 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);
        }
        restore_flags(flags);

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

free_and_ebusy:
        kfree(action);
        restore_flags(flags);
        return -EBUSY;

free_and_enomem:
        kfree(action);
        restore_flags(flags);
        return -ENOMEM;
}

void free_irq(unsigned int irq, void *dev_id)
{
        struct irqaction *action;
        struct irqaction *tmp = NULL;
        unsigned long flags;
        struct ino_bucket *bucket = __bucket(irq), *bp;

        if ((bucket != &pil0_dummy_bucket) &&
            (bucket < &ivector_table[0] ||
             bucket >= &ivector_table[NUM_IVECS])) {
                unsigned int *caller;

                __asm__ __volatile__("mov %%i7, %0" : "=r" (caller));
                printk(KERN_CRIT "free_irq: Old style IRQ removal attempt "
                       "from %p, irq %08x.\n", caller, irq);
                return;
        }
        
        action = *(bucket->pil + irq_action);
        if(!action->handler) {
                printk("Freeing free IRQ %d\n", bucket->pil);
                return;
        }
        if(dev_id) {
                for( ; action; action = action->next) {
                        if(action->dev_id == dev_id)
                                break;
                        tmp = action;
                }
                if(!action) {
                        printk("Trying to free free shared IRQ %d\n", bucket->pil);
                        return;
                }
        } else if(action->flags & SA_SHIRQ) {
                printk("Trying to free shared IRQ %d with NULL device ID\n", bucket->pil);
                return;
        }

        if(action->flags & SA_STATIC_ALLOC) {
                printk("Attempt to free statically allocated IRQ %d (%s)\n",
                       bucket->pil, action->name);
                return;
        }

        save_and_cli(flags);
        if(action && tmp)
                tmp->next = action->next;
        else
                *(bucket->pil + irq_action) = action->next;

        if(action->flags & SA_IMAP_MASKED) {
                unsigned long imap = bucket->imap;
                void **vector, *orig;
                int ent;

                orig = bucket->irq_info;
                vector = (void **)orig;

                if ((bucket->flags & IBF_MULTI) != 0) {
                        int other = 0;
                        void *orphan = NULL;
                        for(ent = 0; ent < 4; ent++) {
                                if(vector[ent] == action)
                                        vector[ent] = NULL;
                                else if(vector[ent] != NULL) {
                                        orphan = vector[ent];
                                        other++;
                                }
                        }

                        /* Only free when no other shared irq
                         * uses this bucket.
                         */
                        if(other) {
                                if (other == 1) {
                                        /* Convert back to non-shared bucket. */
                                        bucket->irq_info = orphan;
                                        bucket->flags &= ~(IBF_MULTI);
                                        kfree(vector);
                                }
                                goto out;
                        }
                } else {
                        bucket->irq_info = NULL;
                }

                /* 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++) {
                        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);
        }

out:
        kfree(action);
        restore_flags(flags);
}

#ifdef CONFIG_SMP

/* Who has global_irq_lock. */
unsigned char global_irq_holder = NO_PROC_ID;

static void show(char * str)
{
        int cpu = smp_processor_id();
        int i;

        printk("\n%s, CPU %d:\n", str, cpu);
        printk("irq:  %d [ ", irqs_running());
        for (i = 0; i < smp_num_cpus; i++)
                printk("%u ", __brlock_array[i][BR_GLOBALIRQ_LOCK]);
        printk("]\nbh:   %d [ ",
               (spin_is_locked(&global_bh_lock) ? 1 : 0));
        for (i = 0; i < smp_num_cpus; i++)
                printk("%u ", local_bh_count(i));
        printk("]\n");
}

#define MAXCOUNT 100000000

#if 0
#define SYNC_OTHER_ULTRAS(x)    udelay(x+1)
#else
#define SYNC_OTHER_ULTRAS(x)    membar("#Sync");
#endif

void synchronize_irq(void)
{
        if (irqs_running()) {
                cli();
                sti();
        }
}

static inline void get_irqlock(int cpu)
{
        int count;

        if ((unsigned char)cpu == global_irq_holder)
                return;

        count = MAXCOUNT;
again:
        br_write_lock(BR_GLOBALIRQ_LOCK);
        for (;;) {
                spinlock_t *lock;

                if (!irqs_running() &&
                    (local_bh_count(smp_processor_id()) || !spin_is_locked(&global_bh_lock)))
                        break;

                br_write_unlock(BR_GLOBALIRQ_LOCK);
                lock = &__br_write_locks[BR_GLOBALIRQ_LOCK].lock;
                while (irqs_running() ||
                       spin_is_locked(lock) ||
                       (!local_bh_count(smp_processor_id()) && spin_is_locked(&global_bh_lock))) {
                        if (!--count) {
                                show("get_irqlock");
                                count = (~0 >> 1);
                        }
                        __sti();
                        SYNC_OTHER_ULTRAS(cpu);
                        __cli();
                }
                goto again;
        }

        global_irq_holder = cpu;
}

void __global_cli(void)
{
        unsigned long flags;

        __save_flags(flags);
        if(flags == 0) {
                int cpu = smp_processor_id();
                __cli();
                if (! local_irq_count(cpu))
                        get_irqlock(cpu);
        }
}

void __global_sti(void)
{
        int cpu = smp_processor_id();

        if (! local_irq_count(cpu))
                release_irqlock(cpu);
        __sti();
}

unsigned long __global_save_flags(void)
{
        unsigned long flags, local_enabled, retval;

        __save_flags(flags);
        local_enabled = ((flags == 0) ? 1 : 0);
        retval = 2 + local_enabled;
        if (! local_irq_count(smp_processor_id())) {
                if (local_enabled)
                        retval = 1;
                if (global_irq_holder == (unsigned char) smp_processor_id())
                        retval = 0;
        }
        return retval;
}

void __global_restore_flags(unsigned long flags)
{
        switch (flags) {
        case 0:
                __global_cli();
                break;
        case 1:
                __global_sti();
                break;
        case 2:
                __cli();
                break;
        case 3:
                __sti();
                break;
        default:
        {
                unsigned long pc;
                __asm__ __volatile__("mov %%i7, %0" : "=r" (pc));
                printk("global_restore_flags: Bogon flags(%016lx) caller %016lx\n",
                       flags, pc);
        }
        }
}

#endif /* CONFIG_SMP */

void catch_disabled_ivec(struct pt_regs *regs)
{
        int cpu = smp_processor_id();
        struct ino_bucket *bucket = __bucket(*irq_work(cpu, 0));

        /* We can actually see this on Ultra/PCI PCI cards, which are bridges
         * to other devices.  Here a single IMAP enabled potentially multiple
         * unique interrupt sources (which each do have a unique ICLR register.
         *
         * So what we do is just register that the IVEC arrived, when registered
         * for real the request_irq() code will check the bit and signal
         * a local CPU interrupt for it.
         */
#if 0
        printk("IVEC: Spurious interrupt vector (%x) received at (%016lx)\n",
               bucket - &ivector_table[0], regs->tpc);
#endif
        *irq_work(cpu, 0) = 0;
        bucket->pending = 1;
}

/* Tune this... */
#define FORWARD_VOLUME          12

void handler_irq(int irq, struct pt_regs *regs)
{
        struct ino_bucket *bp, *nbp;
        int cpu = smp_processor_id();
#ifdef CONFIG_SMP
        extern int this_is_starfire;
        int should_forward = (this_is_starfire == 0     &&
                              irq < 10                  &&
                              current->pid != 0);
        unsigned int buddy = 0;

        /* 'cpu' is the MID (ie. UPAID), calculate the MID
         * of our buddy.
         */
        if (should_forward != 0) {
                buddy = cpu_number_map(cpu) + 1;
                if (buddy >= NR_CPUS ||
                    (buddy = cpu_logical_map(buddy)) == -1)
                        buddy = cpu_logical_map(0);

                /* Voo-doo programming. */
                if (cpu_data[buddy].idle_volume < FORWARD_VOLUME)
                        should_forward = 0;
                buddy <<= 26;
        }
#endif

#ifndef CONFIG_SMP
        /*
         * Check for TICK_INT on level 14 softint.
         */
        if ((irq == 14) && (get_softint() & (1UL << 0)))
                irq = 0;
#endif
        clear_softint(1 << irq);

        irq_enter(cpu, irq);
        kstat.irqs[cpu][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
        for ( ; bp != NULL; bp = nbp) {
                unsigned char flags = bp->flags;

                nbp = __bucket(bp->irq_chain);
                if ((flags & IBF_ACTIVE) != 0) {
#ifdef CONFIG_PCI
                        if ((flags & IBF_DMA_SYNC) != 0) {
                                upa_readl(dma_sync_reg_table[bp->synctab_ent]);
                                upa_readq(pci_dma_wsync);
                        }
#endif
                        if ((flags & IBF_MULTI) == 0) {
                                struct irqaction *ap = bp->irq_info;
                                ap->handler(__irq(bp), ap->dev_id, regs);
                        } else {
                                void **vector = (void **)bp->irq_info;
                                int ent;
                                for (ent = 0; ent < 4; ent++) {
                                        struct irqaction *ap = vector[ent];
                                        if (ap != NULL)
                                                ap->handler(__irq(bp), ap->dev_id, regs);
                                }
                        }
                        /* Only the dummy bucket lacks IMAP/ICLR. */
                        if (bp->pil != 0) {
#ifdef CONFIG_SMP
                                /* Ok, here is what is going on:
                                 * 1) Retargeting IRQs on Starfire is very
                                 *    expensive so just forget about it on them.
                                 * 2) Moving around very high priority interrupts
                                 *    is a losing game.
                                 * 3) If the current cpu is idle, interrupts are
                                 *    useful work, so keep them here.  But do not
                                 *    pass to our neighbour if he is not very idle.
                                 */
                                if (should_forward != 0) {
                                        /* Push it to our buddy. */
                                        should_forward = 0;
                                        upa_writel(buddy | IMAP_VALID, bp->imap);
                                }
#endif
                                upa_writel(ICLR_IDLE, bp->iclr);
                        }
                } else
                        bp->pending = 1;
        }
        irq_exit(cpu, irq);
}

#ifdef CONFIG_BLK_DEV_FD
extern void floppy_interrupt(int irq, void *dev_cookie, struct pt_regs *regs);

void sparc_floppy_irq(int irq, void *dev_cookie, struct pt_regs *regs)
{
        struct irqaction *action = *(irq + irq_action);
        struct ino_bucket *bucket;
        int cpu = smp_processor_id();

        irq_enter(cpu, irq);
        kstat.irqs[cpu][irq]++;

        *(irq_work(cpu, irq)) = 0;
        bucket = (struct ino_bucket *)action->mask;

        floppy_interrupt(irq, dev_cookie, regs);
        upa_writel(ICLR_IDLE, bucket->iclr);

        irq_exit(cpu, irq);
}
#endif

/* The following assumes that the branch lies before the place we
 * are branching to.  This is the case for a trap vector...
 * You have been warned.
 */
#define SPARC_BRANCH(dest_addr, inst_addr) \
          (0x10800000 | ((((dest_addr)-(inst_addr))>>2)&0x3fffff))

#define SPARC_NOP (0x01000000)

static void install_fast_irq(unsigned int cpu_irq,
                             void (*handler)(int, void *, struct pt_regs *))
{
        extern unsigned long sparc64_ttable_tl0;
        unsigned long ttent = (unsigned long) &sparc64_ttable_tl0;
        unsigned int *insns;

        ttent += 0x820;
        ttent += (cpu_irq - 1) << 5;
        insns = (unsigned int *) ttent;
        insns[0] = SPARC_BRANCH(((unsigned long) handler),
                                ((unsigned long)&insns[0]));
        insns[1] = SPARC_NOP;
        __asm__ __volatile__("membar #StoreStore; flush %0" : : "r" (ttent));
}

int request_fast_irq(unsigned int irq,
                     void (*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;

        /* No pil0 dummy buckets allowed here. */
        if (bucket < &ivector_table[0] ||
            bucket >= &ivector_table[NUM_IVECS]) {
                unsigned int *caller;

                __asm__ __volatile__("mov %%i7, %0" : "=r" (caller));
                printk(KERN_CRIT "request_fast_irq: Old style IRQ registry attempt "
                       "from %p, irq %08x.\n", caller, irq);
                return -EINVAL;
        }       
        
        /* Only IMAP style interrupts can be registered as fast. */
        if(bucket->pil == 0)
                return -EINVAL;

        if(!handler)
                return -EINVAL;

        if ((bucket->pil == 0) || (bucket->pil == 14)) {
                printk("request_fast_irq: Trying to register shared IRQ 0 or 14.\n");
                return -EBUSY;
        }

        action = *(bucket->pil + irq_action);
        if(action) {
                if(action->flags & SA_SHIRQ)
                        panic("Trying to register fast irq when already shared.\n");
                if(irqflags & SA_SHIRQ)
                        panic("Trying to register fast irq as shared.\n");
                printk("request_fast_irq: Trying to register yet already owned.\n");
                return -EBUSY;
        }

        save_and_cli(flags);
        if(irqflags & SA_STATIC_ALLOC) {
                if(static_irq_count < MAX_STATIC_ALLOC)
                        action = &static_irqaction[static_irq_count++];
                else
                        printk("Request for IRQ%d (%s) SA_STATIC_ALLOC failed "
                               "using kmalloc\n", bucket->pil, name);
        }
        if(action == NULL)
                action = (struct irqaction *)kmalloc(sizeof(struct irqaction),
                                                     GFP_KERNEL);
        if(!action) {
                restore_flags(flags);
                return -ENOMEM;
        }
        install_fast_irq(bucket->pil, handler);

        bucket->irq_info = action;
        bucket->flags |= IBF_ACTIVE;

        action->mask = (unsigned long) bucket;
        action->handler = handler;
        action->flags = irqflags | SA_IMAP_MASKED;
        action->dev_id = NULL;
        action->name = name;
        action->next = NULL;

        *(bucket->pil + irq_action) = action;
        enable_irq(irq);

        restore_flags(flags);

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

/* 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;
}

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

/* This is gets the master TICK_INT timer going. */
void init_timers(void (*cfunc)(int, void *, struct pt_regs *),
                 unsigned long *clock)
{
        unsigned long pstate;
        extern unsigned long timer_tick_offset;
        int node, err;
#ifdef CONFIG_SMP
        extern void smp_tick_init(void);
#endif

        node = linux_cpus[0].prom_node;
        *clock = prom_getint(node, "clock-frequency");
        timer_tick_offset = *clock / HZ;
#ifdef CONFIG_SMP
        smp_tick_init();
#endif

        /* Register IRQ handler. */
        err = request_irq(build_irq(0, 0, 0UL, 0UL), cfunc, (SA_INTERRUPT | SA_STATIC_ALLOC),
                          "timer", NULL);

        if(err) {
                prom_printf("Serious problem, cannot register TICK_INT\n");
                prom_halt();
        }

        /* Guarentee that the following sequences execute
         * uninterrupted.
         */
        __asm__ __volatile__("rdpr      %%pstate, %0\n\t"
                             "wrpr      %0, %1, %%pstate"
                             : "=r" (pstate)
                             : "i" (PSTATE_IE));

        /* Set things up so user can access tick register for profiling
         * purposes.  Also workaround BB_ERRATA_1 by doing a dummy
         * read back of %tick after writing it.
         */
        __asm__ __volatile__("
                sethi   %%hi(0x80000000), %%g1
                ba,pt   %%xcc, 1f
                 sllx   %%g1, 32, %%g1
                .align  64
        1:      rd      %%tick, %%g2
                add     %%g2, 6, %%g2
                andn    %%g2, %%g1, %%g2
                wrpr    %%g2, 0, %%tick
                rdpr    %%tick, %%g0"
        : /* no outputs */
        : /* no inputs */
        : "g1", "g2");

        /* Workaround for Spitfire Errata (#54 I think??), I discovered
         * this via Sun BugID 4008234, mentioned in Solaris-2.5.1 patch
         * number 103640.
         *
         * On Blackbird writes to %tick_cmpr can fail, the
         * workaround seems to be to execute the wr instruction
         * at the start of an I-cache line, and perform a dummy
         * read back from %tick_cmpr right after writing to it. -DaveM
         */
        __asm__ __volatile__("
                rd      %%tick, %%g1
                ba,pt   %%xcc, 1f
                 add    %%g1, %0, %%g1
                .align  64
        1:      wr      %%g1, 0x0, %%tick_cmpr
                rd      %%tick_cmpr, %%g0"
        : /* no outputs */
        : "r" (timer_tick_offset)
        : "g1");

        /* Restore PSTATE_IE. */
        __asm__ __volatile__("wrpr      %0, 0x0, %%pstate"
                             : /* no outputs */
                             : "r" (pstate));

        sti();
}

#ifdef CONFIG_SMP
static int retarget_one_irq(struct irqaction *p, int goal_cpu)
{
        extern int this_is_starfire;
        struct ino_bucket *bucket = __bucket(p->mask);
        unsigned long imap = bucket->imap;
        unsigned int tid;

        /* Never change this, it causes problems on Ex000 systems. */
        if (bucket->pil == 12)
                return goal_cpu;

        if(this_is_starfire == 0) {
                tid = __cpu_logical_map[goal_cpu] << 26;
        } else {
                extern unsigned int starfire_translate(unsigned long imap,
                                                       unsigned int upaid);

                tid = (starfire_translate(imap, __cpu_logical_map[goal_cpu]) << 26);
        }
        upa_writel(IMAP_VALID | (tid & IMAP_TID), imap);

        goal_cpu++;
        if(goal_cpu >= NR_CPUS ||
           __cpu_logical_map[goal_cpu] == -1)
                goal_cpu = 0;
        return goal_cpu;
}

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

        save_and_cli(flags);
        cpu = 0;
        for(level = 0; level < NR_IRQS; level++) {
                struct irqaction *p = irq_action[level];
                while(p) {
                        if(p->flags & SA_IMAP_MASKED)
                                cpu = retarget_one_irq(p, cpu);
                        p = p->next;
                }
        }
        restore_flags(flags);
}
#endif


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
        ldxa    [%%g0] %0, %%g1
        ldxa    [%%g2] %1, %%g1
        stxa    %%g0, [%%g0] %0
        membar  #Sync
"       : /* no outputs */
        : "i" (ASI_INTR_RECEIVE), "i" (ASI_UDB_INTR_R)
        : "g1", "g2");
}

void enable_prom_timer(void)
{
        if(!prom_timers)
                return;

        /* Set it to whatever was there before. */
        prom_timers->limit1 = prom_limit1;
        prom_timers->count1 = 0;
        prom_timers->limit0 = prom_limit0;
        prom_timers->count0 = 0;
}

void __init init_IRQ(void)
{
        static int called = 0;

        if (called == 0) {
                called = 1;
                map_prom_timers();
                kill_prom_timer();
                memset(&ivector_table[0], 0, sizeof(ivector_table));
#ifndef CONFIG_SMP
                memset(&__up_workvec[0], 0, sizeof(__up_workvec));
#endif
        }

        /* 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");
}

void init_irq_proc(void)
{
        /* For now, nothing... */
}