Linux 2.6.13-rc4

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

/* irq.c: FRV IRQ handling
 *
 * Copyright (C) 2003, 2004 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * 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.
 */

/*
 * (mostly architecture independent, will move to kernel/irq.c in 2.5.)
 *
 * IRQs are in fact implemented a bit like signal handlers for the kernel.
 * Naturally it's not a 1:1 relation, but there are similarities.
 */

#include <linux/config.h>
#include <linux/ptrace.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/timex.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
#include <linux/kernel_stat.h>
#include <linux/irq.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>

#include <asm/atomic.h>
#include <asm/io.h>
#include <asm/smp.h>
#include <asm/system.h>
#include <asm/bitops.h>
#include <asm/uaccess.h>
#include <asm/pgalloc.h>
#include <asm/delay.h>
#include <asm/irq.h>
#include <asm/irc-regs.h>
#include <asm/irq-routing.h>
#include <asm/gdb-stub.h>

extern void __init fpga_init(void);
extern void __init route_mb93493_irqs(void);

static void register_irq_proc (unsigned int irq);

/*
 * Special irq handlers.
 */

irqreturn_t no_action(int cpl, void *dev_id, struct pt_regs *regs) { return IRQ_HANDLED; }

atomic_t irq_err_count;

/*
 * Generic, controller-independent functions:
 */
int show_interrupts(struct seq_file *p, void *v)
{
        struct irqaction *action;
        struct irq_group *group;
        unsigned long flags;
        int level, grp, ix, i, j;

        i = *(loff_t *) v;

        switch (i) {
        case 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');
                break;

        case 1 ... NR_IRQ_GROUPS * NR_IRQ_ACTIONS_PER_GROUP:
                local_irq_save(flags);

                grp = (i - 1) / NR_IRQ_ACTIONS_PER_GROUP;
                group = irq_groups[grp];
                if (!group)
                        goto skip;

                ix = (i - 1) % NR_IRQ_ACTIONS_PER_GROUP;
                action = group->actions[ix];
                if (!action)
                        goto skip;

                seq_printf(p, "%3d: ", i - 1);

#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 - 1]);
#endif

                level = group->sources[ix]->level - frv_irq_levels;

                seq_printf(p, " %12s@%x", group->sources[ix]->muxname, level);
                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:
                local_irq_restore(flags);
                break;

        case NR_IRQ_GROUPS * NR_IRQ_ACTIONS_PER_GROUP + 1:
                seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
                break;

        default:
                break;
        }

        return 0;
}


/*
 * 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 and Enables are
 *      nested.
 *      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.
 */

void disable_irq_nosync(unsigned int irq)
{
        struct irq_source *source;
        struct irq_group *group;
        struct irq_level *level;
        unsigned long flags;
        int idx = irq & (NR_IRQ_ACTIONS_PER_GROUP - 1);

        group = irq_groups[irq >> NR_IRQ_LOG2_ACTIONS_PER_GROUP];
        if (!group)
                BUG();

        source = group->sources[idx];
        if (!source)
                BUG();

        level = source->level;

        spin_lock_irqsave(&level->lock, flags);

        if (group->control) {
                if (!group->disable_cnt[idx]++)
                        group->control(group, idx, 0);
        } else if (!level->disable_count++) {
                __set_MASK(level - frv_irq_levels);
        }

        spin_unlock_irqrestore(&level->lock, flags);
}

/**
 *      disable_irq - disable an irq and wait for completion
 *      @irq: Interrupt to disable
 *
 *      Disable the selected interrupt line.  Enables and Disables are
 *      nested.
 *      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);

#ifdef CONFIG_SMP
        if (!local_irq_count(smp_processor_id())) {
                do {
                        barrier();
                } while (irq_desc[irq].status & IRQ_INPROGRESS);
        }
#endif
}

/**
 *      enable_irq - enable handling of an irq
 *      @irq: Interrupt to enable
 *
 *      Undoes the effect of one call to disable_irq().  If this
 *      matches the last disable, processing of interrupts on this
 *      IRQ line is re-enabled.
 *
 *      This function may be called from IRQ context.
 */

void enable_irq(unsigned int irq)
{
        struct irq_source *source;
        struct irq_group *group;
        struct irq_level *level;
        unsigned long flags;
        int idx = irq & (NR_IRQ_ACTIONS_PER_GROUP - 1);
        int count;

        group = irq_groups[irq >> NR_IRQ_LOG2_ACTIONS_PER_GROUP];
        if (!group)
                BUG();

        source = group->sources[idx];
        if (!source)
                BUG();

        level = source->level;

        spin_lock_irqsave(&level->lock, flags);

        if (group->control)
                count = group->disable_cnt[idx];
        else
                count = level->disable_count;

        switch (count) {
        case 1:
                if (group->control) {
                        if (group->actions[idx])
                                group->control(group, idx, 1);
                } else {
                        if (level->usage)
                                __clr_MASK(level - frv_irq_levels);
                }
                /* fall-through */

        default:
                count--;
                break;

        case 0:
                printk("enable_irq(%u) unbalanced from %p\n", irq, __builtin_return_address(0));
        }

        if (group->control)
                group->disable_cnt[idx] = count;
        else
                level->disable_count = count;

        spin_unlock_irqrestore(&level->lock, flags);
}

/*****************************************************************************/
/*
 * handles all normal device IRQ's
 * - registers are referred to by the __frame variable (GR28)
 * - IRQ distribution is complicated in this arch because of the many PICs, the
 *   way they work and the way they cascade
 */
asmlinkage void do_IRQ(void)
{
        struct irq_source *source;
        int level, cpu;

        level = (__frame->tbr >> 4) & 0xf;
        cpu = smp_processor_id();

#if 0
        {
                static u32 irqcount;
                *(volatile u32 *) 0xe1200004 = ~((irqcount++ << 8) | level);
                *(volatile u16 *) 0xffc00100 = (u16) ~0x9999;
                mb();
        }
#endif

        if ((unsigned long) __frame - (unsigned long) (current + 1) < 512)
                BUG();

        __set_MASK(level);
        __clr_RC(level);
        __clr_IRL();

        kstat_this_cpu.irqs[level]++;

        irq_enter();

        for (source = frv_irq_levels[level].sources; source; source = source->next)
                source->doirq(source);

        irq_exit();

        __clr_MASK(level);

        /* only process softirqs if we didn't interrupt another interrupt handler */
        if ((__frame->psr & PSR_PIL) == PSR_PIL_0)
                if (local_softirq_pending())
                        do_softirq();

#ifdef CONFIG_PREEMPT
        local_irq_disable();
        while (--current->preempt_count == 0) {
                if (!(__frame->psr & PSR_S) ||
                    current->need_resched == 0 ||
                    in_interrupt())
                        break;
                current->preempt_count++;
                local_irq_enable();
                preempt_schedule();
                local_irq_disable();
        }
#endif

#if 0
        {
                *(volatile u16 *) 0xffc00100 = (u16) ~0x6666;
                mb();
        }
#endif

} /* end do_IRQ() */

/*****************************************************************************/
/*
 * handles all NMIs when not co-opted by the debugger
 * - registers are referred to by the __frame variable (GR28)
 */
asmlinkage void do_NMI(void)
{
} /* end do_NMI() */

/*****************************************************************************/
/**
 *      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("Bad boy: %s (at 0x%x) called us without a dev_id!\n",
                               devname, (&irq)[-1]);
        }
#endif

        if ((irq >> NR_IRQ_LOG2_ACTIONS_PER_GROUP) >= NR_IRQ_GROUPS)
                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;
        action->mask = CPU_MASK_NONE;
        action->name = devname;
        action->next = NULL;
        action->dev_id = dev_id;

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

/**
 *      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)
{
        struct irq_source *source;
        struct irq_group *group;
        struct irq_level *level;
        struct irqaction **p, **pp;
        unsigned long flags;

        if ((irq >> NR_IRQ_LOG2_ACTIONS_PER_GROUP) >= NR_IRQ_GROUPS)
                return;

        group = irq_groups[irq >> NR_IRQ_LOG2_ACTIONS_PER_GROUP];
        if (!group)
                BUG();

        source = group->sources[irq & (NR_IRQ_ACTIONS_PER_GROUP - 1)];
        if (!source)
                BUG();

        level = source->level;
        p = &group->actions[irq & (NR_IRQ_ACTIONS_PER_GROUP - 1)];

        spin_lock_irqsave(&level->lock, flags);

        for (pp = p; *pp; pp = &(*pp)->next) {
                struct irqaction *action = *pp;

                if (action->dev_id != dev_id)
                        continue;

                /* found it - remove from the list of entries */
                *pp = action->next;

                level->usage--;

                if (p == pp && group->control)
                        group->control(group, irq & (NR_IRQ_ACTIONS_PER_GROUP - 1), 0);

                if (level->usage == 0)
                        __set_MASK(level - frv_irq_levels);

                spin_unlock_irqrestore(&level->lock,flags);

#ifdef CONFIG_SMP
                /* Wait to make sure it's not being used on another CPU */
                while (desc->status & IRQ_INPROGRESS)
                        barrier();
#endif
                kfree(action);
                return;
        }
}

/*
 * IRQ autodetection code..
 *
 * This depends on the fact that any interrupt that comes in on to an
 * unassigned IRQ will cause GxICR_DETECT to be set
 */

static DECLARE_MUTEX(probe_sem);

/**
 *      probe_irq_on    - begin an interrupt autodetect
 *
 *      Commence probing for an interrupt. The interrupts are scanned
 *      and a mask of potential interrupt lines is returned.
 *
 */

unsigned long probe_irq_on(void)
{
        down(&probe_sem);
        return 0;
}

/*
 * Return a mask of triggered interrupts (this
 * can handle only legacy ISA interrupts).
 */

/**
 *      probe_irq_mask - scan a bitmap of interrupt lines
 *      @val:   mask of interrupts to consider
 *
 *      Scan the ISA bus interrupt lines and return a bitmap of
 *      active interrupts. The interrupt probe logic state is then
 *      returned to its previous value.
 *
 *      Note: we need to scan all the irq's even though we will
 *      only return ISA irq numbers - just so that we reset them
 *      all to a known state.
 */
unsigned int probe_irq_mask(unsigned long xmask)
{
        up(&probe_sem);
        return 0;
}

/*
 * Return the one interrupt that triggered (this can
 * handle any interrupt source).
 */

/**
 *      probe_irq_off   - end an interrupt autodetect
 *      @xmask: mask of potential interrupts (unused)
 *
 *      Scans the unused interrupt lines and returns the line which
 *      appears to have triggered the interrupt. If no interrupt was
 *      found then zero is returned. If more than one interrupt is
 *      found then minus the first candidate is returned to indicate
 *      their is doubt.
 *
 *      The interrupt probe logic state is returned to its previous
 *      value.
 *
 *      BUGS: When used in a module (which arguably shouldnt happen)
 *      nothing prevents two IRQ probe callers from overlapping. The
 *      results of this are non-optimal.
 */

int probe_irq_off(unsigned long xmask)
{
        up(&probe_sem);
        return -1;
}

/* this was setup_x86_irq but it seems pretty generic */
int setup_irq(unsigned int irq, struct irqaction *new)
{
        struct irq_source *source;
        struct irq_group *group;
        struct irq_level *level;
        struct irqaction **p, **pp;
        unsigned long flags;

        group = irq_groups[irq >> NR_IRQ_LOG2_ACTIONS_PER_GROUP];
        if (!group)
                BUG();

        source = group->sources[irq & (NR_IRQ_ACTIONS_PER_GROUP - 1)];
        if (!source)
                BUG();

        level = source->level;

        p = &group->actions[irq & (NR_IRQ_ACTIONS_PER_GROUP - 1)];

        /*
         * 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);
        }

        /* must juggle the interrupt processing stuff with interrupts disabled */
        spin_lock_irqsave(&level->lock, flags);

        /* can't share interrupts unless all parties agree to */
        if (level->usage != 0 && !(level->flags & new->flags & SA_SHIRQ)) {
                spin_unlock_irqrestore(&level->lock,flags);
                return -EBUSY;
        }

        /* add new interrupt at end of irq queue */
        pp = p;
        while (*pp)
                pp = &(*pp)->next;

        *pp = new;

        level->usage++;
        level->flags = new->flags;

        /* turn the interrupts on */
        if (level->usage == 1)
                __clr_MASK(level - frv_irq_levels);

        if (p == pp && group->control)
                group->control(group, irq & (NR_IRQ_ACTIONS_PER_GROUP - 1), 1);

        spin_unlock_irqrestore(&level->lock, flags);
        register_irq_proc(irq);
        return 0;
}

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

#define HEX_DIGITS 8

static unsigned int parse_hex_value (const char *buffer,
                                     unsigned long count, unsigned long *ret)
{
        unsigned char hexnum [HEX_DIGITS];
        unsigned long value;
        int i;

        if (!count)
                return -EINVAL;
        if (count > HEX_DIGITS)
                count = HEX_DIGITS;
        if (copy_from_user(hexnum, buffer, count))
                return -EFAULT;

        /*
         * Parse the first 8 characters as a hex string, any non-hex char
         * is end-of-string. '00e1', 'e1', '00E1', 'E1' are all the same.
         */
        value = 0;

        for (i = 0; i < count; i++) {
                unsigned int c = hexnum[i];

                switch (c) {
                        case '0' ... '9': c -= '0'; break;
                        case 'a' ... 'f': c -= 'a'-10; break;
                        case 'A' ... 'F': c -= 'A'-10; break;
                default:
                        goto out;
                }
                value = (value << 4) | c;
        }
out:
        *ret = value;
        return 0;
}


static int prof_cpu_mask_read_proc (char *page, char **start, off_t off,
                        int count, int *eof, void *data)
{
        unsigned long *mask = (unsigned long *) data;
        if (count < HEX_DIGITS+1)
                return -EINVAL;
        return sprintf (page, "%08lx\n", *mask);
}

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

        show_state();
        err = parse_hex_value(buffer, count, &new_value);
        if (err)
                return err;

        *mask = new_value;
        return full_count;
}

#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, "%d", irq);

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

unsigned long prof_cpu_mask = -1;

void init_irq_proc (void)
{
        struct proc_dir_entry *entry;
        int i;

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

        /* create /proc/irq/prof_cpu_mask */
        entry = create_proc_entry("prof_cpu_mask", 0600, root_irq_dir);
        if (!entry)
            return;

        entry->nlink = 1;
        entry->data = (void *)&prof_cpu_mask;
        entry->read_proc = prof_cpu_mask_read_proc;
        entry->write_proc = prof_cpu_mask_write_proc;

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

/*****************************************************************************/
/*
 * initialise the interrupt system
 */
void __init init_IRQ(void)
{
        route_cpu_irqs();
        fpga_init();
#ifdef CONFIG_FUJITSU_MB93493
        route_mb93493_irqs();
#endif
} /* end init_IRQ() */