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/*

 *      linux/arch/alpha/kernel/irq.c

 *

 *      Copyright (C) 1995 Linus Torvalds

 *

 * 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/config.h>

#include <linux/kernel.h>

#include <linux/ptrace.h>

#include <linux/errno.h>

#include <linux/kernel_stat.h>

#include <linux/signal.h>

#include <linux/sched.h>

#include <linux/interrupt.h>

#include <linux/slab.h>

#include <linux/random.h>

#include <linux/init.h>

#include <linux/irq.h>

#include <linux/proc_fs.h>

#include <asm/system.h>

#include <asm/io.h>

#include <asm/bitops.h>

#include <asm/uaccess.h>

/*

 * Controller mappings for all interrupt sources:

 */

irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned = {

        [0 ... NR_IRQS-1] = { 0, &no_irq_type, NULL, 0, SPIN_LOCK_UNLOCKED}

};

static void register_irq_proc(unsigned int irq);

volatile unsigned long irq_err_count;

/*

 * Special irq handlers.

 */

void no_action(int cpl, void *dev_id, struct pt_regs *regs) { }

/*

 * Generic no controller code

 */

static void no_irq_enable_disable(unsigned int irq) { }

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

static void

no_irq_ack(unsigned int irq)

{

        irq_err_count++;

        printk(KERN_CRIT "Unexpected IRQ trap at vector %u\n", irq);

}

struct hw_interrupt_type no_irq_type = {

        typename:       "none",

        startup:        no_irq_startup,

        shutdown:       no_irq_enable_disable,

        enable:         no_irq_enable_disable,

        disable:        no_irq_enable_disable,

        ack:            no_irq_ack,

        end:            no_irq_enable_disable,

};

int

handle_IRQ_event(unsigned int irq, struct pt_regs *regs,

                 struct irqaction *action)

{

        int status;

        int cpu = smp_processor_id();

        kstat.irqs[cpu][irq]++;

        irq_enter(cpu, irq);

        status = 1;     /* Force the "do bottom halves" bit */

        do {

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

                        __sti();

                else

                        __cli();

                status |= action->flags;

                action->handler(irq, action->dev_id, regs);

                action = action->next;

        } while (action);

        if (status & SA_SAMPLE_RANDOM)

                add_interrupt_randomness(irq);

        __cli();

        irq_exit(cpu, irq);

        return status;

}

/*

 * 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.

 */

void inline

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);

}

/*

 * Synchronous version of the above, making sure the IRQ is

 * no longer running on any other IRQ..

 */

void

disable_irq(unsigned int irq)

{

        disable_irq_nosync(irq);

        if (!local_irq_count(smp_processor_id())) {

                do {

                        barrier();

                } while (irq_desc[irq].status & IRQ_INPROGRESS);

        }

}

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);

}

int

setup_irq(unsigned int irq, struct irqaction * new)

{

        int shared = 0;

        struct irqaction *old, **p;

        unsigned long flags;

        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;

        if ((old = *p) != 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 | IRQ_INPROGRESS);

                desc->handler->startup(irq);

        }

        spin_unlock_irqrestore(&desc->lock,flags);

        return 0;

}

static struct proc_dir_entry * root_irq_dir;

static struct proc_dir_entry * irq_dir[NR_IRQS];

#ifdef CONFIG_SMP

static struct proc_dir_entry * smp_affinity_entry[NR_IRQS];

static char irq_user_affinity[NR_IRQS];

static unsigned long irq_affinity[NR_IRQS] = { [0 ... NR_IRQS-1] = ~0UL };

static void

select_smp_affinity(int irq)

{

        static int last_cpu;

        int cpu = last_cpu + 1;

        if (! irq_desc[irq].handler->set_affinity || irq_user_affinity[irq])

                return;

        while (((cpu_present_mask >> cpu) & 1) == 0)

                cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);

        last_cpu = cpu;

        irq_affinity[irq] = 1UL << cpu;

        irq_desc[irq].handler->set_affinity(irq, 1UL << cpu);

}

#define HEX_DIGITS 16

static int

irq_affinity_read_proc (char *page, char **start, off_t off,

                        int count, int *eof, void *data)

{

        if (count < HEX_DIGITS+1)

                return -EINVAL;

        return sprintf (page, "%016lx\n", irq_affinity[(long)data]);

}

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

irq_affinity_write_proc(struct file *file, const char *buffer,

                        unsigned long count, void *data)

{

        int irq = (long) data, full_count = count, err;

        unsigned long new_value;

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

                return -EIO;

        err = parse_hex_value(buffer, count, &new_value);

        /* The special value 0 means release control of the

           affinity to kernel.  */

        if (new_value == 0) {

                irq_user_affinity[irq] = 0;

                select_smp_affinity(irq);

        }

        /* 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.  */

        else if (!(new_value & cpu_present_mask))

                return -EINVAL;

        else {

                irq_affinity[irq] = new_value;

                irq_user_affinity[irq] = 1;

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

        }

        return full_count;

}

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, "%016lx\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;

        err = parse_hex_value(buffer, count, &new_value);

        if (err)

                return err;

        *mask = new_value;

        return full_count;

}

#endif /* CONFIG_SMP */

#define MAX_NAMELEN 10

static void

register_irq_proc (unsigned int irq)

{

#ifdef CONFIG_SMP

        struct proc_dir_entry *entry;

#endif

        char name [MAX_NAMELEN];

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

                return;

        memset(name, 0, MAX_NAMELEN);

        sprintf(name, "%d", irq);

        /* create /proc/irq/1234 */

        irq_dir[irq] = proc_mkdir(name, root_irq_dir);

#ifdef CONFIG_SMP

        if (irq_desc[irq].handler->set_affinity) {

                /* 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;

        }

#endif

}

unsigned long prof_cpu_mask = ~0UL;

void

init_irq_proc (void)

{

#ifdef CONFIG_SMP

        struct proc_dir_entry *entry;

#endif

        int i;

        /* create /proc/irq */

        root_irq_dir = proc_mkdir("irq", 0);

#ifdef CONFIG_SMP

        /* create /proc/irq/prof_cpu_mask */

        entry = create_proc_entry("prof_cpu_mask", 0600, root_irq_dir);

        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;

#endif

        /*

         * Create entries for all existing IRQs. If the number of IRQs

         * is greater the 1/4 the total dynamic inode space for /proc,

         * don't pollute the inode space

         */

        if (ACTUAL_NR_IRQS < (PROC_NDYNAMIC / 4)) {

                for (i = 0; i < ACTUAL_NR_IRQS; i++) {

                        if (irq_desc[i].handler == &no_irq_type)

                                continue;

                        register_irq_proc(i);

                }

        }

}

int

request_irq(unsigned int irq, void (*handler)(int, void *, struct pt_regs *),

            unsigned long irqflags, const char * devname, void *dev_id)

{

        int retval;

        struct irqaction * action;

        if (irq >= ACTUAL_NR_IRQS)

                return -EINVAL;

        if (!handler)

                return -EINVAL;

#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) && !dev_id) {

                printk(KERN_ERR

                       "Bad boy: %s (at %p) called us without a dev_id!\n",

                       devname, __builtin_return_address(0));

        }

#endif

        action = (struct irqaction *)

                        kmalloc(sizeof(struct irqaction), GFP_KERNEL);

        if (!action)

                return -ENOMEM;

        action->handler = handler;

        action->flags = irqflags;

        action->mask = 0;

        action->name = devname;

        action->next = NULL;

        action->dev_id = dev_id;

#ifdef CONFIG_SMP

        select_smp_affinity(irq);

#endif

        retval = setup_irq(irq, action);

        if (retval)

                kfree(action);

        return retval;

}

void

free_irq(unsigned int irq, void *dev_id)

{

        irq_desc_t *desc;

        struct irqaction **p;

        unsigned long flags;

        if (irq >= ACTUAL_NR_IRQS) {

                printk(KERN_CRIT "Trying to free IRQ%d\n", irq);

                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 - now remove it from the list of entries.  */

                        *pp = action->next;

                        if (!desc->action) {

                                desc->status |= IRQ_DISABLED;

                                desc->handler->shutdown(irq);

                        }

                        spin_unlock_irqrestore(&desc->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;

                }

                printk(KERN_ERR "Trying to free free IRQ%d\n",irq);

                spin_unlock_irqrestore(&desc->lock,flags);

                return;

        }

}

int

get_irq_list(char *buf)

{

#ifdef CONFIG_SMP

        int j;

#endif

        int i;

        struct irqaction * action;

        char *p = buf;

#ifdef CONFIG_SMP

        p += sprintf(p, "           ");

        for (i = 0; i < smp_num_cpus; i++)

                p += sprintf(p, "CPU%d       ", i);

#ifdef DO_BROADCAST_INTS

        for (i = 0; i < smp_num_cpus; i++)

                p += sprintf(p, "TRY%d       ", i);

#endif

        *p++ = '\n';

#endif

        for (i = 0; i < ACTUAL_NR_IRQS; i++) {

                action = irq_desc[i].action;

                if (!action)

                        continue;

                p += sprintf(p, "%3d: ",i);

#ifndef CONFIG_SMP

                p += sprintf(p, "%10u ", kstat_irqs(i));

#else

                for (j = 0; j < smp_num_cpus; j++)

                        p += sprintf(p, "%10u ",

                                     kstat.irqs[cpu_logical_map(j)][i]);

#ifdef DO_BROADCAST_INTS

                for (j = 0; j < smp_num_cpus; j++)

                        p += sprintf(p, "%10lu ",

                                     irq_attempt(cpu_logical_map(j), i));

#endif

#endif

                p += sprintf(p, " %14s", irq_desc[i].handler->typename);

                p += sprintf(p, "  %c%s",

                             (action->flags & SA_INTERRUPT)?'+':' ',

                             action->name);

                for (action=action->next; action; action = action->next) {

                        p += sprintf(p, ", %c%s",

                                     (action->flags & SA_INTERRUPT)?'+':' ',

                                     action->name);

                }

                *p++ = '\n';

        }

#if CONFIG_SMP

        p += sprintf(p, "IPI: ");

        for (j = 0; j < smp_num_cpus; j++)

                p += sprintf(p, "%10lu ",

                             cpu_data[cpu_logical_map(j)].ipi_count);

        p += sprintf(p, "\n");

#endif

        p += sprintf(p, "ERR: %10lu\n", irq_err_count);

        return p - buf;

}

/*

 * handle_irq handles all normal device IRQ's (the special

 * SMP cross-CPU interrupts have their own specific

 * handlers).

 */

#define MAX_ILLEGAL_IRQS 16

void

handle_irq(int irq, struct pt_regs * regs)

{

        /*

         * We ack quickly, we don't want the irq controller

         * thinking we're snobs just because some other CPU has

         * disabled global interrupts (we have already done the

         * INT_ACK cycles, it's too late to try to pretend to the

         * controller that we aren't taking the interrupt).

         *

         * 0 return value means that this irq is already being

         * handled by some other CPU. (or is disabled)

         */

        int cpu = smp_processor_id();

        irq_desc_t *desc = irq_desc + irq;

        struct irqaction * action;

        unsigned int status;

        static unsigned int illegal_count=0;

        if ((unsigned) irq > ACTUAL_NR_IRQS && illegal_count < MAX_ILLEGAL_IRQS ) {

                irq_err_count++;

                illegal_count++;

                printk(KERN_CRIT "device_interrupt: illegal interrupt %d\n",

                       irq);

                return;

        }

        irq_attempt(cpu, irq)++;

        spin_lock_irq(&desc->lock); /* mask also the higher prio events */

        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 handle_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, regs, action);

                spin_lock(&desc->lock);

                if (!(desc->status & IRQ_PENDING)

                    || (desc->status & IRQ_LEVEL))

                        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.