initial commit with v2.6.9

[linux-2.6.9-moxart.git] / arch / um / kernel / irq.c

/* 
 * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
 * Licensed under the GPL
 * Derived (i.e. mostly copied) from arch/i386/kernel/irq.c:
 *      Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
 */

#include "linux/config.h"
#include "linux/kernel.h"
#include "linux/module.h"
#include "linux/smp.h"
#include "linux/irq.h"
#include "linux/kernel_stat.h"
#include "linux/interrupt.h"
#include "linux/random.h"
#include "linux/slab.h"
#include "linux/file.h"
#include "linux/proc_fs.h"
#include "linux/init.h"
#include "linux/seq_file.h"
#include "linux/profile.h"
#include "linux/hardirq.h"
#include "asm/irq.h"
#include "asm/hw_irq.h"
#include "asm/atomic.h"
#include "asm/signal.h"
#include "asm/system.h"
#include "asm/errno.h"
#include "asm/uaccess.h"
#include "user_util.h"
#include "kern_util.h"
#include "irq_user.h"
#include "irq_kern.h"

static void register_irq_proc (unsigned int irq);

irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned = {
        [0 ... NR_IRQS-1] = {
                .handler = &no_irq_type,
                .lock = SPIN_LOCK_UNLOCKED
        }
};

/*
 * Generic no controller code
 */

static void enable_none(unsigned int irq) { }
static unsigned int startup_none(unsigned int irq) { return 0; }
static void disable_none(unsigned int irq) { }
static void ack_none(unsigned int irq)
{
/*
 * 'what should we do if we get a hw irq event on an illegal vector'.
 * each architecture has to answer this themselves, it doesn't deserve
 * a generic callback i think.
 */
#ifdef CONFIG_X86
        printk(KERN_ERR "unexpected IRQ trap at vector %02x\n", irq);
#ifdef CONFIG_X86_LOCAL_APIC
        /*
         * Currently unexpected vectors happen only on SMP and APIC.
         * We _must_ ack these because every local APIC has only N
         * irq slots per priority level, and a 'hanging, unacked' IRQ
         * holds up an irq slot - in excessive cases (when multiple
         * unexpected vectors occur) that might lock up the APIC
         * completely.
         */
        ack_APIC_irq();
#endif
#endif
}

/* startup is the same as "enable", shutdown is same as "disable" */
#define shutdown_none   disable_none
#define end_none        enable_none

struct hw_interrupt_type no_irq_type = {
        "none",
        startup_none,
        shutdown_none,
        enable_none,
        disable_none,
        ack_none,
        end_none
};

/*
 * Generic, controller-independent functions:
 */

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 (j=0; j<NR_CPUS; j++)
                        if (cpu_online(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 (j = 0; j < NR_CPUS; j++)
                        if (cpu_online(j))
                                seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
#endif
                seq_printf(p, " %14s", irq_desc[i].handler->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);
        } else if (i == NR_IRQS) {
                seq_printf(p, "NMI: ");
                for (j = 0; j < NR_CPUS; j++)
                        if (cpu_online(j))
                                seq_printf(p, "%10u ", nmi_count(j));
                seq_putc(p, '\n');
        }

        return 0;
}

/*
 * This should really return information about whether
 * we should do bottom half handling etc. Right now we
 * end up _always_ checking the bottom half, which is a
 * waste of time and is not what some drivers would
 * prefer.
 */
int handle_IRQ_event(unsigned int irq, struct pt_regs * regs, 
                     struct irqaction * action)
{
        int status = 1; /* Force the "do bottom halves" bit */
        int ret, retval = 0;

        if (!(action->flags & SA_INTERRUPT))
                local_irq_enable();

        do {
                ret = action->handler(irq, action->dev_id, regs);
                if (ret == IRQ_HANDLED)
                        status |= action->flags;
                retval |= ret;
                action = action->next;
        } while (action);
        if (status & SA_SAMPLE_RANDOM)
                add_interrupt_randomness(irq);

        local_irq_disable();

        return retval;
}

/*
 * Generic enable/disable code: this just calls
 * down into the PIC-specific version for the actual
 * hardware disable after having gotten the irq
 * controller lock. 
 */
 
/**
 *      disable_irq_nosync - disable an irq without waiting
 *      @irq: Interrupt to disable
 *
 *      Disable the selected interrupt line. Disables of an interrupt
 *      stack. Unlike disable_irq(), this function does not ensure existing
 *      instances of the IRQ handler have completed before returning.
 *
 *      This function may be called from IRQ context.
 */
 
inline void disable_irq_nosync(unsigned int irq)
{
        irq_desc_t *desc = irq_desc + irq;
        unsigned long flags;

        spin_lock_irqsave(&desc->lock, flags);
        if (!desc->depth++) {
                desc->status |= IRQ_DISABLED;
                desc->handler->disable(irq);
        }
        spin_unlock_irqrestore(&desc->lock, flags);
}

#ifdef CONFIG_SMP
inline void synchronize_irq(unsigned int irq)
{
        /* is there anything to synchronize with? */
        if (!irq_desc[irq].action)
                return;
 
        while (irq_desc[irq].status & IRQ_INPROGRESS)
                cpu_relax();
}
#endif

/**
 *      disable_irq - disable an irq and wait for completion
 *      @irq: Interrupt to disable
 *
 *      Disable the selected interrupt line. Disables of an interrupt
 *      stack. That is for two disables you need two enables. This
 *      function waits for any pending IRQ handlers for this interrupt
 *      to complete before returning. If you use this function while
 *      holding a resource the IRQ handler may need you will deadlock.
 *
 *      This function may be called - with care - from IRQ context.
 */
 
void disable_irq(unsigned int irq)
{
        disable_irq_nosync(irq);
        synchronize_irq(irq);
}

/**
 *      enable_irq - enable interrupt handling on an irq
 *      @irq: Interrupt to enable
 *
 *      Re-enables the processing of interrupts on this IRQ line
 *      providing no disable_irq calls are now in effect.
 *
 *      This function may be called from IRQ context.
 */
 
void enable_irq(unsigned int irq)
{
        irq_desc_t *desc = irq_desc + irq;
        unsigned long flags;

        spin_lock_irqsave(&desc->lock, flags);
        switch (desc->depth) {
        case 1: {
                unsigned int status = desc->status & ~IRQ_DISABLED;
                desc->status = status;
                if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) {
                        desc->status = status | IRQ_REPLAY;
                        hw_resend_irq(desc->handler,irq);
                }
                desc->handler->enable(irq);
                /* fall-through */
        }
        default:
                desc->depth--;
                break;
        case 0:
                printk(KERN_ERR "enable_irq() unbalanced from %p\n",
                       __builtin_return_address(0));
        }
        spin_unlock_irqrestore(&desc->lock, flags);
}

/*
 * do_IRQ handles all normal device IRQ's (the special
 * SMP cross-CPU interrupts have their own specific
 * handlers).
 */
unsigned int do_IRQ(int irq, union uml_pt_regs *regs)
{       
        /* 
         * 0 return value means that this irq is already being
         * handled by some other CPU. (or is disabled)
         */
        irq_desc_t *desc = irq_desc + irq;
        struct irqaction * action;
        unsigned int status;

        irq_enter();
        kstat_this_cpu.irqs[irq]++;
        spin_lock(&desc->lock);
        desc->handler->ack(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 (!(status & (IRQ_DISABLED | IRQ_INPROGRESS))) {
                action = desc->action;
                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 (!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);
                handle_IRQ_event(irq, (struct pt_regs *) regs, action);
                spin_lock(&desc->lock);
                
                if (!(desc->status & IRQ_PENDING))
                        break;
                desc->status &= ~IRQ_PENDING;
        }
        desc->status &= ~IRQ_INPROGRESS;
out:
        /*
         * The ->end() handler has to deal with interrupts which got
         * disabled while the handler was running.
         */
        desc->handler->end(irq);
        spin_unlock(&desc->lock);

        irq_exit();

        return 1;
}

/**
 *      request_irq - allocate an interrupt line
 *      @irq: Interrupt line to allocate
 *      @handler: Function to be called when the IRQ occurs
 *      @irqflags: Interrupt type flags
 *      @devname: An ascii name for the claiming device
 *      @dev_id: A cookie passed back to the handler function
 *
 *      This call allocates interrupt resources and enables the
 *      interrupt line and IRQ handling. From the point this
 *      call is made your handler function may be invoked. Since
 *      your handler function must clear any interrupt the board 
 *      raises, you must take care both to initialise your hardware
 *      and to set up the interrupt handler in the right order.
 *
 *      Dev_id must be globally unique. Normally the address of the
 *      device data structure is used as the cookie. Since the handler
 *      receives this value it makes sense to use it.
 *
 *      If your interrupt is shared you must pass a non NULL dev_id
 *      as this is required when freeing the interrupt.
 *
 *      Flags:
 *
 *      SA_SHIRQ                Interrupt is shared
 *
 *      SA_INTERRUPT            Disable local interrupts while processing
 *
 *      SA_SAMPLE_RANDOM        The interrupt can be used for entropy
 *
 */
 
int request_irq(unsigned int irq,
                irqreturn_t (*handler)(int, void *, struct pt_regs *),
                unsigned long irqflags, 
                const char * devname,
                void *dev_id)
{
        int retval;
        struct irqaction * action;

#if 1
        /*
         * Sanity-check: shared interrupts should REALLY pass in
         * a real dev-ID, otherwise we'll have trouble later trying
         * to figure out which interrupt is which (messes up the
         * interrupt freeing logic etc).
         */
        if (irqflags & SA_SHIRQ) {
                if (!dev_id)
                        printk(KERN_ERR "Bad boy: %s (at 0x%x) called us "
                               "without a dev_id!\n", devname, (&irq)[-1]);
        }
#endif

        if (irq >= NR_IRQS)
                return -EINVAL;
        if (!handler)
                return -EINVAL;

        action = (struct irqaction *)
                        kmalloc(sizeof(struct irqaction), GFP_KERNEL);
        if (!action)
                return -ENOMEM;

        action->handler = handler;
        action->flags = irqflags;
        cpus_clear(action->mask);
        action->name = devname;
        action->next = NULL;
        action->dev_id = dev_id;

        retval = setup_irq(irq, action);
        if (retval)
                kfree(action);
        return retval;
}

EXPORT_SYMBOL(request_irq);

int um_request_irq(unsigned int irq, int fd, int type,
                   irqreturn_t (*handler)(int, void *, struct pt_regs *),
                   unsigned long irqflags, const char * devname,
                   void *dev_id)
{
        int err;

        err = request_irq(irq, handler, irqflags, devname, dev_id);
        if(err)
                return(err);

        if(fd != -1)
                err = activate_fd(irq, fd, type, dev_id);
        return(err);
}
EXPORT_SYMBOL(um_request_irq);
EXPORT_SYMBOL(reactivate_fd);

/* this was setup_x86_irq but it seems pretty generic */
int setup_irq(unsigned int irq, struct irqaction * new)
{
        int shared = 0;
        unsigned long flags;
        struct irqaction *old, **p;
        irq_desc_t *desc = irq_desc + irq;

        /*
         * Some drivers like serial.c use request_irq() heavily,
         * so we have to be careful not to interfere with a
         * running system.
         */
        if (new->flags & SA_SAMPLE_RANDOM) {
                /*
                 * This function might sleep, we want to call it first,
                 * outside of the atomic block.
                 * 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);
        }

        /*
         * The following block of code has to be executed atomically
         */
        spin_lock_irqsave(&desc->lock,flags);
        p = &desc->action;
        old = *p;
        if (old != NULL) {
                /* Can't share interrupts unless both agree to */
                if (!(old->flags & new->flags & SA_SHIRQ)) {
                        spin_unlock_irqrestore(&desc->lock,flags);
                        return -EBUSY;
                }

                /* add new interrupt at end of irq queue */
                do {
                        p = &old->next;
                        old = *p;
                } while (old);
                shared = 1;
        }

        *p = new;

        if (!shared) {
                desc->depth = 0;
                desc->status &= ~IRQ_DISABLED;
                desc->handler->startup(irq);
        }
        spin_unlock_irqrestore(&desc->lock,flags);

        register_irq_proc(irq);
        return 0;
}

/**
 *      free_irq - free an interrupt
 *      @irq: Interrupt line to free
 *      @dev_id: Device identity to free
 *
 *      Remove an interrupt handler. The handler is removed and if the
 *      interrupt line is no longer in use by any driver it is disabled.
 *      On a shared IRQ the caller must ensure the interrupt is disabled
 *      on the card it drives before calling this function. The function
 *      does not return until any executing interrupts for this IRQ
 *      have completed.
 *
 *      This function may be called from interrupt context. 
 *
 *      Bugs: Attempting to free an irq in a handler for the same irq hangs
 *            the machine.
 */
 
void free_irq(unsigned int irq, void *dev_id)
{
        irq_desc_t *desc;
        struct irqaction **p;
        unsigned long flags;

        if (irq >= NR_IRQS)
                return;

        desc = irq_desc + irq;
        spin_lock_irqsave(&desc->lock,flags);
        p = &desc->action;
        for (;;) {
                struct irqaction * action = *p;
                if (action) {
                        struct irqaction **pp = p;
                        p = &action->next;
                        if (action->dev_id != dev_id)
                                continue;

                        /* Found it - now remove it from the list of entries */
                        *pp = action->next;
                        if (!desc->action) {
                                desc->status |= IRQ_DISABLED;
                                desc->handler->shutdown(irq);
                        }
                        free_irq_by_irq_and_dev(irq, dev_id);
                        spin_unlock_irqrestore(&desc->lock,flags);

                        /* Wait to make sure it's not being used on another CPU */
                        synchronize_irq(irq);
                        kfree(action);
                        return;
                }
                printk(KERN_ERR "Trying to free free IRQ%d\n",irq);
                spin_unlock_irqrestore(&desc->lock,flags);
                return;
        }
}

EXPORT_SYMBOL(free_irq);

/* These are initialized by sysctl_init, which is called from init/main.c */
static struct proc_dir_entry * root_irq_dir;
static struct proc_dir_entry * irq_dir [NR_IRQS];
static struct proc_dir_entry * smp_affinity_entry [NR_IRQS];

/* These are read and written as longs, so a read won't see a partial write
 * even during a race.
 */
static cpumask_t irq_affinity [NR_IRQS] = { [0 ... NR_IRQS-1] = CPU_MASK_ALL };

static int irq_affinity_read_proc (char *page, char **start, off_t off,
                        int count, int *eof, void *data)
{
        int len = cpumask_scnprintf(page, count, irq_affinity[(long)data]);
        if (count - len < 2)
                return -EINVAL;
        len += sprintf(page + len, "\n");
        return len;
}

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

        if (!irq_desc[irq].handler->set_affinity)
                return -EIO;

        err = cpumask_parse(buffer, count, new_value);
        if(err)
                return(err);

#ifdef CONFIG_SMP
        /*
         * 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.
         */
        { cpumask_t tmp;
          cpus_and(tmp, new_value, cpu_online_map);
          if (cpus_empty(tmp))
                  return -EINVAL;
        }
#endif

        irq_affinity[irq] = new_value;
        irq_desc[irq].handler->set_affinity(irq, new_value);

        return full_count;
}

#define MAX_NAMELEN 10

static void register_irq_proc (unsigned int irq)
{
        struct proc_dir_entry *entry;
        char name [MAX_NAMELEN];

        if (!root_irq_dir || (irq_desc[irq].handler == &no_irq_type) ||
            irq_dir[irq])
                return;

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

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

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

        entry->nlink = 1;
        entry->data = (void *)(long)irq;
        entry->read_proc = irq_affinity_read_proc;
        entry->write_proc = irq_affinity_write_proc;

        smp_affinity_entry[irq] = entry;
}

void __init init_irq_proc (void)
{
        int i;

        /* create /proc/irq */
        root_irq_dir = proc_mkdir("irq", 0);

        /* create /proc/irq/prof_cpu_mask */
        create_prof_cpu_mask(root_irq_dir);

        /*
         * Create entries for all existing IRQs.
         */
        for (i = 0; i < NR_IRQS; i++)
                register_irq_proc(i);
}

static spinlock_t irq_spinlock = SPIN_LOCK_UNLOCKED;

unsigned long irq_lock(void)
{
        unsigned long flags;

        spin_lock_irqsave(&irq_spinlock, flags);
        return(flags);
}

void irq_unlock(unsigned long flags)
{
        spin_unlock_irqrestore(&irq_spinlock, flags);
}

unsigned long probe_irq_on(void)
{
        return(0);
}

EXPORT_SYMBOL(probe_irq_on);

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

EXPORT_SYMBOL(probe_irq_off);

static unsigned int startup_SIGIO_irq(unsigned int irq)
{
        return(0);
}

static void shutdown_SIGIO_irq(unsigned int irq)
{
}

static void enable_SIGIO_irq(unsigned int irq)
{
}

static void disable_SIGIO_irq(unsigned int irq)
{
}

static void mask_and_ack_SIGIO(unsigned int irq)
{
}

static void end_SIGIO_irq(unsigned int irq)
{
}

static unsigned int startup_SIGVTALRM_irq(unsigned int irq)
{
        return(0);
}

static void shutdown_SIGVTALRM_irq(unsigned int irq)
{
}

static void enable_SIGVTALRM_irq(unsigned int irq)
{
}

static void disable_SIGVTALRM_irq(unsigned int irq)
{
}

static void mask_and_ack_SIGVTALRM(unsigned int irq)
{
}

static void end_SIGVTALRM_irq(unsigned int irq)
{
}

static struct hw_interrupt_type SIGIO_irq_type = {
        "SIGIO",
        startup_SIGIO_irq,
        shutdown_SIGIO_irq,
        enable_SIGIO_irq,
        disable_SIGIO_irq,
        mask_and_ack_SIGIO,
        end_SIGIO_irq,
        NULL
};

static struct hw_interrupt_type SIGVTALRM_irq_type = {
        "SIGVTALRM",
        startup_SIGVTALRM_irq,
        shutdown_SIGVTALRM_irq,
        enable_SIGVTALRM_irq,
        disable_SIGVTALRM_irq,
        mask_and_ack_SIGVTALRM,
        end_SIGVTALRM_irq,
        NULL
};

void __init init_IRQ(void)
{
        int i;

        irq_desc[TIMER_IRQ].status = IRQ_DISABLED;
        irq_desc[TIMER_IRQ].action = 0;
        irq_desc[TIMER_IRQ].depth = 1;
        irq_desc[TIMER_IRQ].handler = &SIGVTALRM_irq_type;
        enable_irq(TIMER_IRQ);
        for(i=1;i<NR_IRQS;i++){
                irq_desc[i].status = IRQ_DISABLED;
                irq_desc[i].action = 0;
                irq_desc[i].depth = 1;
                irq_desc[i].handler = &SIGIO_irq_type;
                enable_irq(i);
        }
        init_irq_signals(0);
}

/*
 * Overrides for Emacs so that we follow Linus's tabbing style.
 * Emacs will notice this stuff at the end of the file and automatically
 * adjust the settings for this buffer only.  This must remain at the end
 * of the file.
 * ---------------------------------------------------------------------------
 * Local variables:
 * c-file-style: "linux"
 * End:
 */