[TG3]: Set minimal hw interrupt mitigation.

[linux-2.6/verdex.git] / arch / ppc64 / kernel / irq.c

/*
 *  arch/ppc/kernel/irq.c
 *
 *  Derived from arch/i386/kernel/irq.c
 *    Copyright (C) 1992 Linus Torvalds
 *  Adapted from arch/i386 by Gary Thomas
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *  Updated and modified by Cort Dougan (cort@cs.nmt.edu)
 *    Copyright (C) 1996 Cort Dougan
 *  Adapted for Power Macintosh by Paul Mackerras
 *    Copyright (C) 1996 Paul Mackerras (paulus@cs.anu.edu.au)
 *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 * This file contains the code used by various IRQ handling routines:
 * asking for different IRQ's should be done through these routines
 * instead of just grabbing them. Thus setups with different IRQ numbers
 * shouldn't result in any weird surprises, and installing new handlers
 * should be easier.
 */

#include <linux/errno.h>
#include <linux/module.h>
#include <linux/threads.h>
#include <linux/kernel_stat.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/timex.h>
#include <linux/config.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/proc_fs.h>
#include <linux/random.h>
#include <linux/kallsyms.h>
#include <linux/profile.h>
#include <linux/bitops.h>

#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/irq.h>
#include <asm/cache.h>
#include <asm/prom.h>
#include <asm/ptrace.h>
#include <asm/iSeries/LparData.h>
#include <asm/machdep.h>
#include <asm/paca.h>

#ifdef CONFIG_SMP
extern void iSeries_smp_message_recv( struct pt_regs * );
#endif

extern irq_desc_t irq_desc[NR_IRQS];
EXPORT_SYMBOL(irq_desc);

int distribute_irqs = 1;
int __irq_offset_value;
int ppc_spurious_interrupts;
unsigned long lpevent_count;
u64 ppc64_interrupt_controller;

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

        if (i == 0) {
                seq_printf(p, "           ");
                for (j=0; j<NR_CPUS; j++) {
                        if (cpu_online(j))
                                seq_printf(p, "CPU%d       ",j);
                }
                seq_putc(p, '\n');
        }

        if (i < NR_IRQS) {
                desc = get_irq_desc(i);
                spin_lock_irqsave(&desc->lock, flags);
                action = desc->action;
                if (!action || !action->handler)
                        goto skip;
                seq_printf(p, "%3d: ", i);
#ifdef CONFIG_SMP
                for (j = 0; j < NR_CPUS; j++) {
                        if (cpu_online(j))
                                seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
                }
#else
                seq_printf(p, "%10u ", kstat_irqs(i));
#endif /* CONFIG_SMP */
                if (desc->handler)
                        seq_printf(p, " %s ", desc->handler->typename );
                else
                        seq_printf(p, "  None      ");
                seq_printf(p, "%s", (desc->status & IRQ_LEVEL) ? "Level " : "Edge  ");
                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(&desc->lock, flags);
        } else if (i == NR_IRQS)
                seq_printf(p, "BAD: %10u\n", ppc_spurious_interrupts);
        return 0;
}

#ifdef CONFIG_HOTPLUG_CPU
void fixup_irqs(cpumask_t map)
{
        unsigned int irq;
        static int warned;

        for_each_irq(irq) {
                cpumask_t mask;

                if (irq_desc[irq].status & IRQ_PER_CPU)
                        continue;

                cpus_and(mask, irq_affinity[irq], map);
                if (any_online_cpu(mask) == NR_CPUS) {
                        printk("Breaking affinity for irq %i\n", irq);
                        mask = map;
                }
                if (irq_desc[irq].handler->set_affinity)
                        irq_desc[irq].handler->set_affinity(irq, mask);
                else if (irq_desc[irq].action && !(warned++))
                        printk("Cannot set affinity for irq %i\n", irq);
        }

        local_irq_enable();
        mdelay(1);
        local_irq_disable();
}
#endif

extern int noirqdebug;

/*
 * Eventually, this should take an array of interrupts and an array size
 * so it can dispatch multiple interrupts.
 */
void ppc_irq_dispatch_handler(struct pt_regs *regs, int irq)
{
        int status;
        struct irqaction *action;
        int cpu = smp_processor_id();
        irq_desc_t *desc = get_irq_desc(irq);
        irqreturn_t action_ret;
#ifdef CONFIG_IRQSTACKS
        struct thread_info *curtp, *irqtp;
#endif

        kstat_cpu(cpu).irqs[irq]++;

        if (desc->status & IRQ_PER_CPU) {
                /* no locking required for CPU-local interrupts: */
                ack_irq(irq);
                action_ret = handle_IRQ_event(irq, regs, desc->action);
                desc->handler->end(irq);
                return;
        }

        spin_lock(&desc->lock);
        ack_irq(irq);   
        /*
           REPLAY is when Linux resends an IRQ that was dropped earlier
           WAITING is used by probe to mark irqs that are being tested
           */
        status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
        status |= IRQ_PENDING; /* we _want_ to handle it */

        /*
         * If the IRQ is disabled for whatever reason, we cannot
         * use the action we have.
         */
        action = NULL;
        if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
                action = desc->action;
                if (!action || !action->handler) {
                        ppc_spurious_interrupts++;
                        printk(KERN_DEBUG "Unhandled interrupt %x, disabled\n", irq);
                        /* We can't call disable_irq here, it would deadlock */
                        if (!desc->depth)
                                desc->depth = 1;
                        desc->status |= IRQ_DISABLED;
                        /* This is not a real spurrious interrupt, we
                         * have to eoi it, so we jump to out
                         */
                        mask_irq(irq);
                        goto out;
                }
                status &= ~IRQ_PENDING; /* we commit to handling */
                status |= IRQ_INPROGRESS; /* we are handling it */
        }
        desc->status = status;

        /*
         * If there is no IRQ handler or it was disabled, exit early.
           Since we set PENDING, if another processor is handling
           a different instance of this same irq, the other processor
           will take care of it.
         */
        if (unlikely(!action))
                goto out;

        /*
         * Edge triggered interrupts need to remember
         * pending events.
         * This applies to any hw interrupts that allow a second
         * instance of the same irq to arrive while we are in do_IRQ
         * or in the handler. But the code here only handles the _second_
         * instance of the irq, not the third or fourth. So it is mostly
         * useful for irq hardware that does not mask cleanly in an
         * SMP environment.
         */
        for (;;) {
                spin_unlock(&desc->lock);

#ifdef CONFIG_IRQSTACKS
                /* Switch to the irq stack to handle this */
                curtp = current_thread_info();
                irqtp = hardirq_ctx[smp_processor_id()];
                if (curtp != irqtp) {
                        irqtp->task = curtp->task;
                        irqtp->flags = 0;
                        action_ret = call_handle_IRQ_event(irq, regs, action, irqtp);
                        irqtp->task = NULL;
                        if (irqtp->flags)
                                set_bits(irqtp->flags, &curtp->flags);
                } else
#endif
                        action_ret = handle_IRQ_event(irq, regs, action);

                spin_lock(&desc->lock);
                if (!noirqdebug)
                        note_interrupt(irq, desc, action_ret);
                if (likely(!(desc->status & IRQ_PENDING)))
                        break;
                desc->status &= ~IRQ_PENDING;
        }
out:
        desc->status &= ~IRQ_INPROGRESS;
        /*
         * The ->end() handler has to deal with interrupts which got
         * disabled while the handler was running.
         */
        if (desc->handler) {
                if (desc->handler->end)
                        desc->handler->end(irq);
                else if (desc->handler->enable)
                        desc->handler->enable(irq);
        }
        spin_unlock(&desc->lock);
}

#ifdef CONFIG_PPC_ISERIES
void do_IRQ(struct pt_regs *regs)
{
        struct paca_struct *lpaca;
        struct ItLpQueue *lpq;

        irq_enter();

#ifdef CONFIG_DEBUG_STACKOVERFLOW
        /* Debugging check for stack overflow: is there less than 2KB free? */
        {
                long sp;

                sp = __get_SP() & (THREAD_SIZE-1);

                if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
                        printk("do_IRQ: stack overflow: %ld\n",
                                sp - sizeof(struct thread_info));
                        dump_stack();
                }
        }
#endif

        lpaca = get_paca();
#ifdef CONFIG_SMP
        if (lpaca->lppaca.int_dword.fields.ipi_cnt) {
                lpaca->lppaca.int_dword.fields.ipi_cnt = 0;
                iSeries_smp_message_recv(regs);
        }
#endif /* CONFIG_SMP */
        lpq = lpaca->lpqueue_ptr;
        if (lpq && ItLpQueue_isLpIntPending(lpq))
                lpevent_count += ItLpQueue_process(lpq, regs);

        irq_exit();

        if (lpaca->lppaca.int_dword.fields.decr_int) {
                lpaca->lppaca.int_dword.fields.decr_int = 0;
                /* Signal a fake decrementer interrupt */
                timer_interrupt(regs);
        }
}

#else   /* CONFIG_PPC_ISERIES */

void do_IRQ(struct pt_regs *regs)
{
        int irq;

        irq_enter();

#ifdef CONFIG_DEBUG_STACKOVERFLOW
        /* Debugging check for stack overflow: is there less than 2KB free? */
        {
                long sp;

                sp = __get_SP() & (THREAD_SIZE-1);

                if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
                        printk("do_IRQ: stack overflow: %ld\n",
                                sp - sizeof(struct thread_info));
                        dump_stack();
                }
        }
#endif

        irq = ppc_md.get_irq(regs);

        if (irq >= 0)
                ppc_irq_dispatch_handler(regs, irq);
        else
                /* That's not SMP safe ... but who cares ? */
                ppc_spurious_interrupts++;

        irq_exit();
}
#endif  /* CONFIG_PPC_ISERIES */

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

        if (once)
                return;

        once++;

        ppc_md.init_IRQ();
        irq_ctx_init();
}

#ifndef CONFIG_PPC_ISERIES
/*
 * Virtual IRQ mapping code, used on systems with XICS interrupt controllers.
 */

#define UNDEFINED_IRQ 0xffffffff
unsigned int virt_irq_to_real_map[NR_IRQS];

/*
 * Don't use virtual irqs 0, 1, 2 for devices.
 * The pcnet32 driver considers interrupt numbers < 2 to be invalid,
 * and 2 is the XICS IPI interrupt.
 * We limit virtual irqs to 17 less than NR_IRQS so that when we
 * offset them by 16 (to reserve the first 16 for ISA interrupts)
 * we don't end up with an interrupt number >= NR_IRQS.
 */
#define MIN_VIRT_IRQ    3
#define MAX_VIRT_IRQ    (NR_IRQS - NUM_ISA_INTERRUPTS - 1)
#define NR_VIRT_IRQS    (MAX_VIRT_IRQ - MIN_VIRT_IRQ + 1)

void
virt_irq_init(void)
{
        int i;
        for (i = 0; i < NR_IRQS; i++)
                virt_irq_to_real_map[i] = UNDEFINED_IRQ;
}

/* Create a mapping for a real_irq if it doesn't already exist.
 * Return the virtual irq as a convenience.
 */
int virt_irq_create_mapping(unsigned int real_irq)
{
        unsigned int virq, first_virq;
        static int warned;

        if (ppc64_interrupt_controller == IC_OPEN_PIC)
                return real_irq;        /* no mapping for openpic (for now) */

        /* don't map interrupts < MIN_VIRT_IRQ */
        if (real_irq < MIN_VIRT_IRQ) {
                virt_irq_to_real_map[real_irq] = real_irq;
                return real_irq;
        }

        /* map to a number between MIN_VIRT_IRQ and MAX_VIRT_IRQ */
        virq = real_irq;
        if (virq > MAX_VIRT_IRQ)
                virq = (virq % NR_VIRT_IRQS) + MIN_VIRT_IRQ;

        /* search for this number or a free slot */
        first_virq = virq;
        while (virt_irq_to_real_map[virq] != UNDEFINED_IRQ) {
                if (virt_irq_to_real_map[virq] == real_irq)
                        return virq;
                if (++virq > MAX_VIRT_IRQ)
                        virq = MIN_VIRT_IRQ;
                if (virq == first_virq)
                        goto nospace;   /* oops, no free slots */
        }

        virt_irq_to_real_map[virq] = real_irq;
        return virq;

 nospace:
        if (!warned) {
                printk(KERN_CRIT "Interrupt table is full\n");
                printk(KERN_CRIT "Increase NR_IRQS (currently %d) "
                       "in your kernel sources and rebuild.\n", NR_IRQS);
                warned = 1;
        }
        return NO_IRQ;
}

/*
 * In most cases will get a hit on the very first slot checked in the
 * virt_irq_to_real_map.  Only when there are a large number of
 * IRQs will this be expensive.
 */
unsigned int real_irq_to_virt_slowpath(unsigned int real_irq)
{
        unsigned int virq;
        unsigned int first_virq;

        virq = real_irq;

        if (virq > MAX_VIRT_IRQ)
                virq = (virq % NR_VIRT_IRQS) + MIN_VIRT_IRQ;

        first_virq = virq;

        do {
                if (virt_irq_to_real_map[virq] == real_irq)
                        return virq;

                virq++;

                if (virq >= MAX_VIRT_IRQ)
                        virq = 0;

        } while (first_virq != virq);

        return NO_IRQ;

}

#endif /* CONFIG_PPC_ISERIES */

#ifdef CONFIG_IRQSTACKS
struct thread_info *softirq_ctx[NR_CPUS];
struct thread_info *hardirq_ctx[NR_CPUS];

void irq_ctx_init(void)
{
        struct thread_info *tp;
        int i;

        for_each_cpu(i) {
                memset((void *)softirq_ctx[i], 0, THREAD_SIZE);
                tp = softirq_ctx[i];
                tp->cpu = i;
                tp->preempt_count = SOFTIRQ_OFFSET;

                memset((void *)hardirq_ctx[i], 0, THREAD_SIZE);
                tp = hardirq_ctx[i];
                tp->cpu = i;
                tp->preempt_count = HARDIRQ_OFFSET;
        }
}

void do_softirq(void)
{
        unsigned long flags;
        struct thread_info *curtp, *irqtp;

        if (in_interrupt())
                return;

        local_irq_save(flags);

        if (local_softirq_pending()) {
                curtp = current_thread_info();
                irqtp = softirq_ctx[smp_processor_id()];
                irqtp->task = curtp->task;
                call_do_softirq(irqtp);
                irqtp->task = NULL;
        }

        local_irq_restore(flags);
}
EXPORT_SYMBOL(do_softirq);

#endif /* CONFIG_IRQSTACKS */

static int __init setup_noirqdistrib(char *str)
{
        distribute_irqs = 0;
        return 1;
}

__setup("noirqdistrib", setup_noirqdistrib);