1 files changed, 774 insertions, 0 deletions

diff --git a/arch/alpha/kernel/irq.c b/arch/alpha/kernel/irq.c
new file mode 100644
index 000000000000..b6114f5c0d2b
--- /dev/null
+++ b/arch/alpha/kernel/irq.c
@@ -0,0 +1,774 @@
+/*
+ *      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/module.h>
+#include <linux/errno.h>
+#include <linux/kernel_stat.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/ptrace.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 <linux/seq_file.h>
+#include <linux/profile.h>
+#include <linux/bitops.h>
+
+#include <asm/system.h>
+#include <asm/io.h>
+#include <asm/uaccess.h>
+
+/*
+ * Controller mappings for all interrupt sources:
+ */
+irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned = {
+        [0 ... NR_IRQS-1] = {
+                .handler = &no_irq_type,
+                .lock = SPIN_LOCK_UNLOCKED
+        }
+};
+
+static void register_irq_proc(unsigned int irq);
+
+volatile unsigned long irq_err_count;
+
+/*
+ * Special irq handlers.
+ */
+
+irqreturn_t no_action(int cpl, void *dev_id, struct pt_regs *regs)
+{
+        return IRQ_NONE;
+}
+
+/*
+ * 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 = 1; /* Force the "do bottom halves" bit */
+        int ret;
+
+        do {
+                if (!(action->flags & SA_INTERRUPT))
+                        local_irq_enable();
+                else
+                        local_irq_disable();
+
+                ret = action->handler(irq, action->dev_id, regs);
+                if (ret == IRQ_HANDLED)
+                        status |= action->flags;
+                action = action->next;
+        } while (action);
+        if (status & SA_SAMPLE_RANDOM)
+                add_interrupt_randomness(irq);
+        local_irq_disable();
+
+        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);
+        synchronize_irq(irq);
+}
+
+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;
+
+        if (desc->handler == &no_irq_type)
+                return -ENOSYS;
+
+        /*
+         * 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_AUTODETECT|IRQ_WAITING|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 cpumask_t irq_affinity[NR_IRQS] = { [0 ... NR_IRQS-1] = CPU_MASK_ALL };
+
+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_possible(cpu))
+                cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
+        last_cpu = cpu;
+
+        irq_affinity[irq] = cpumask_of_cpu(cpu);
+        irq_desc[irq].handler->set_affinity(irq, cpumask_of_cpu(cpu));
+}
+
+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 __user *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);
+
+        /* The special value 0 means release control of the
+           affinity to kernel.  */
+        cpus_and(new_value, new_value, cpu_online_map);
+        if (cpus_empty(new_value)) {
+                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 {
+                irq_affinity[irq] = new_value;
+                irq_user_affinity[irq] = 1;
+                irq_desc[irq].handler->set_affinity(irq, new_value);
+        }
+
+        return full_count;
+}
+
+#endif /* CONFIG_SMP */
+
+#define MAX_NAMELEN 10
+
+static void
+register_irq_proc (unsigned int irq)
+{
+        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);
+
+#ifdef CONFIG_SMP 
+        if (irq_desc[irq].handler->set_affinity) {
+                struct proc_dir_entry *entry;
+                /* create /proc/irq/1234/smp_affinity */
+                entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);
+
+                if (entry) {
+                        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
+}
+
+void
+init_irq_proc (void)
+{
+        int i;
+
+        /* create /proc/irq */
+        root_irq_dir = proc_mkdir("irq", NULL);
+
+#ifdef CONFIG_SMP 
+        /* create /proc/irq/prof_cpu_mask */
+        create_prof_cpu_mask(root_irq_dir);
+#endif
+
+        /*
+         * Create entries for all existing IRQs.
+         */
+        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, irqreturn_t (*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;
+        cpus_clear(action->mask);
+        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;
+}
+
+EXPORT_SYMBOL(request_irq);
+
+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;
+        }
+}
+
+EXPORT_SYMBOL(free_irq);
+
+int
+show_interrupts(struct seq_file *p, void *v)
+{
+#ifdef CONFIG_SMP
+        int j;
+#endif
+        int i = *(loff_t *) v;
+        struct irqaction * action;
+        unsigned long flags;
+
+#ifdef CONFIG_SMP
+        if (i == 0) {
+                seq_puts(p, "           ");
+                for (i = 0; i < NR_CPUS; i++)
+                        if (cpu_online(i))
+                                seq_printf(p, "CPU%d       ", i);
+                seq_putc(p, '\n');
+        }
+#endif
+
+        if (i < ACTUAL_NR_IRQS) {
+                spin_lock_irqsave(&irq_desc[i].lock, flags);
+                action = irq_desc[i].action;
+                if (!action) 
+                        goto unlock;
+                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, "  %c%s",
+                        (action->flags & SA_INTERRUPT)?'+':' ',
+                        action->name);
+
+                for (action=action->next; action; action = action->next) {
+                        seq_printf(p, ", %c%s",
+                                  (action->flags & SA_INTERRUPT)?'+':' ',
+                                   action->name);
+                }
+
+                seq_putc(p, '\n');
+unlock:
+                spin_unlock_irqrestore(&irq_desc[i].lock, flags);
+        } else if (i == ACTUAL_NR_IRQS) {
+#ifdef CONFIG_SMP
+                seq_puts(p, "IPI: ");
+                for (i = 0; i < NR_CPUS; i++)
+                        if (cpu_online(i))
+                                seq_printf(p, "%10lu ", cpu_data[i].ipi_count);
+                seq_putc(p, '\n');
+#endif
+                seq_printf(p, "ERR: %10lu\n", irq_err_count);
+        }
+        return 0;
+}
+
+
+/*
+ * 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: invalid interrupt %d\n",
+                       irq);
+                return;
+        }
+
+        irq_enter();
+        kstat_cpu(cpu).irqs[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.
+         */
+        desc->handler->end(irq);
+        spin_unlock(&desc->lock);
+
+        irq_exit();
+}
+
+/*
+ * IRQ autodetection code..
+ *
+ * This depends on the fact that any interrupt that
+ * comes in on to an unassigned handler will get stuck
+ * with "IRQ_WAITING" cleared and the interrupt
+ * disabled.
+ */
+unsigned long
+probe_irq_on(void)
+{
+        int i;
+        irq_desc_t *desc;
+        unsigned long delay;
+        unsigned long val;
+
+        /* Something may have generated an irq long ago and we want to
+           flush such a longstanding irq before considering it as spurious. */
+        for (i = NR_IRQS-1; i >= 0; i--) {
+                desc = irq_desc + i;
+
+                spin_lock_irq(&desc->lock);
+                if (!irq_desc[i].action) 
+                        irq_desc[i].handler->startup(i);
+                spin_unlock_irq(&desc->lock);
+        }
+
+        /* Wait for longstanding interrupts to trigger. */
+        for (delay = jiffies + HZ/50; time_after(delay, jiffies); )
+                /* about 20ms delay */ barrier();
+
+        /* enable any unassigned irqs (we must startup again here because
+           if a longstanding irq happened in the previous stage, it may have
+           masked itself) first, enable any unassigned irqs. */
+        for (i = NR_IRQS-1; i >= 0; i--) {
+                desc = irq_desc + i;
+
+                spin_lock_irq(&desc->lock);
+                if (!desc->action) {
+                        desc->status |= IRQ_AUTODETECT | IRQ_WAITING;
+                        if (desc->handler->startup(i))
+                                desc->status |= IRQ_PENDING;
+                }
+                spin_unlock_irq(&desc->lock);
+        }
+
+        /*
+         * Wait for spurious interrupts to trigger
+         */
+        for (delay = jiffies + HZ/10; time_after(delay, jiffies); )
+                /* about 100ms delay */ barrier();
+
+        /*
+         * Now filter out any obviously spurious interrupts
+         */
+        val = 0;
+        for (i=0; i<NR_IRQS; i++) {
+                irq_desc_t *desc = irq_desc + i;
+                unsigned int status;
+
+                spin_lock_irq(&desc->lock);
+                status = desc->status;
+
+                if (status & IRQ_AUTODETECT) {
+                        /* It triggered already - consider it spurious. */
+                        if (!(status & IRQ_WAITING)) {
+                                desc->status = status & ~IRQ_AUTODETECT;
+                                desc->handler->shutdown(i);
+                        } else
+                                if (i < 32)
+                                        val |= 1 << i;
+                }
+                spin_unlock_irq(&desc->lock);
+        }
+
+        return val;
+}
+
+EXPORT_SYMBOL(probe_irq_on);
+
+/*
+ * Return a mask of triggered interrupts (this
+ * can handle only legacy ISA interrupts).
+ */
+unsigned int
+probe_irq_mask(unsigned long val)
+{
+        int i;
+        unsigned int mask;
+
+        mask = 0;
+        for (i = 0; i < NR_IRQS; i++) {
+                irq_desc_t *desc = irq_desc + i;
+                unsigned int status;
+
+                spin_lock_irq(&desc->lock);
+                status = desc->status;
+
+                if (status & IRQ_AUTODETECT) {
+                        /* We only react to ISA interrupts */
+                        if (!(status & IRQ_WAITING)) {
+                                if (i < 16)
+                                        mask |= 1 << i;
+                        }
+
+                        desc->status = status & ~IRQ_AUTODETECT;
+                        desc->handler->shutdown(i);
+                }
+                spin_unlock_irq(&desc->lock);
+        }
+
+        return mask & val;
+}
+
+/*
+ * Get the result of the IRQ probe.. A negative result means that
+ * we have several candidates (but we return the lowest-numbered
+ * one).
+ */
+
+int
+probe_irq_off(unsigned long val)
+{
+        int i, irq_found, nr_irqs;
+
+        nr_irqs = 0;
+        irq_found = 0;
+        for (i=0; i<NR_IRQS; i++) {
+                irq_desc_t *desc = irq_desc + i;
+                unsigned int status;
+
+                spin_lock_irq(&desc->lock);
+                status = desc->status;
+
+                if (status & IRQ_AUTODETECT) {
+                        if (!(status & IRQ_WAITING)) {
+                                if (!nr_irqs)
+                                        irq_found = i;
+                                nr_irqs++;
+                        }
+                        desc->status = status & ~IRQ_AUTODETECT;
+                        desc->handler->shutdown(i);
+                }
+                spin_unlock_irq(&desc->lock);
+        }
+
+        if (nr_irqs > 1)
+                irq_found = -irq_found;
+        return irq_found;
+}
+
+EXPORT_SYMBOL(probe_irq_off);
+
+#ifdef CONFIG_SMP
+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)
+                barrier();
+}
+#endif