Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1038 insertions, 0 deletions

diff --git a/arch/arm/kernel/irq.c b/arch/arm/kernel/irq.c
new file mode 100644
index 000000000000..ff187f4308f0
--- /dev/null
+++ b/arch/arm/kernel/irq.c
@@ -0,0 +1,1038 @@
+/*
+ *  linux/arch/arm/kernel/irq.c
+ *
+ *  Copyright (C) 1992 Linus Torvalds
+ *  Modifications for ARM processor Copyright (C) 1995-2000 Russell King.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ *  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.
+ *
+ *  IRQ's 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/kernel_stat.h>
+#include <linux/module.h>
+#include <linux/signal.h>
+#include <linux/ioport.h>
+#include <linux/interrupt.h>
+#include <linux/ptrace.h>
+#include <linux/slab.h>
+#include <linux/random.h>
+#include <linux/smp.h>
+#include <linux/init.h>
+#include <linux/seq_file.h>
+#include <linux/errno.h>
+#include <linux/list.h>
+#include <linux/kallsyms.h>
+#include <linux/proc_fs.h>
+
+#include <asm/irq.h>
+#include <asm/system.h>
+#include <asm/mach/irq.h>
+
+/*
+ * Maximum IRQ count.  Currently, this is arbitary.  However, it should
+ * not be set too low to prevent false triggering.  Conversely, if it
+ * is set too high, then you could miss a stuck IRQ.
+ *
+ * Maybe we ought to set a timer and re-enable the IRQ at a later time?
+ */
+#define MAX_IRQ_CNT     100000
+
+static int noirqdebug;
+static volatile unsigned long irq_err_count;
+static DEFINE_SPINLOCK(irq_controller_lock);
+static LIST_HEAD(irq_pending);
+
+struct irqdesc irq_desc[NR_IRQS];
+void (*init_arch_irq)(void) __initdata = NULL;
+
+/*
+ * No architecture-specific irq_finish function defined in arm/arch/irqs.h.
+ */
+#ifndef irq_finish
+#define irq_finish(irq) do { } while (0)
+#endif
+
+/*
+ * Dummy mask/unmask handler
+ */
+void dummy_mask_unmask_irq(unsigned int irq)
+{
+}
+
+irqreturn_t no_action(int irq, void *dev_id, struct pt_regs *regs)
+{
+        return IRQ_NONE;
+}
+
+void do_bad_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
+{
+        irq_err_count += 1;
+        printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq);
+}
+
+static struct irqchip bad_chip = {
+        .ack    = dummy_mask_unmask_irq,
+        .mask   = dummy_mask_unmask_irq,
+        .unmask = dummy_mask_unmask_irq,
+};
+
+static struct irqdesc bad_irq_desc = {
+        .chip           = &bad_chip,
+        .handle         = do_bad_IRQ,
+        .pend           = LIST_HEAD_INIT(bad_irq_desc.pend),
+        .disable_depth  = 1,
+};
+
+#ifdef CONFIG_SMP
+void synchronize_irq(unsigned int irq)
+{
+        struct irqdesc *desc = irq_desc + irq;
+
+        while (desc->running)
+                barrier();
+}
+EXPORT_SYMBOL(synchronize_irq);
+
+#define smp_set_running(desc)   do { desc->running = 1; } while (0)
+#define smp_clear_running(desc) do { desc->running = 0; } while (0)
+#else
+#define smp_set_running(desc)   do { } while (0)
+#define smp_clear_running(desc) do { } while (0)
+#endif
+
+/**
+ *      disable_irq_nosync - disable an irq without waiting
+ *      @irq: Interrupt to disable
+ *
+ *      Disable the selected interrupt line.  Enables and disables
+ *      are nested.  We do this lazily.
+ *
+ *      This function may be called from IRQ context.
+ */
+void disable_irq_nosync(unsigned int irq)
+{
+        struct irqdesc *desc = irq_desc + irq;
+        unsigned long flags;
+
+        spin_lock_irqsave(&irq_controller_lock, flags);
+        desc->disable_depth++;
+        list_del_init(&desc->pend);
+        spin_unlock_irqrestore(&irq_controller_lock, flags);
+}
+EXPORT_SYMBOL(disable_irq_nosync);
+
+/**
+ *      disable_irq - disable an irq and wait for completion
+ *      @irq: Interrupt to disable
+ *
+ *      Disable the selected interrupt line.  Enables and disables
+ *      are nested.  This functions 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)
+{
+        struct irqdesc *desc = irq_desc + irq;
+
+        disable_irq_nosync(irq);
+        if (desc->action)
+                synchronize_irq(irq);
+}
+EXPORT_SYMBOL(disable_irq);
+
+/**
+ *      enable_irq - enable interrupt handling on an irq
+ *      @irq: Interrupt to enable
+ *
+ *      Re-enables the processing of interrupts on this IRQ line.
+ *      Note that this may call the interrupt handler, so you may
+ *      get unexpected results if you hold IRQs disabled.
+ *
+ *      This function may be called from IRQ context.
+ */
+void enable_irq(unsigned int irq)
+{
+        struct irqdesc *desc = irq_desc + irq;
+        unsigned long flags;
+
+        spin_lock_irqsave(&irq_controller_lock, flags);
+        if (unlikely(!desc->disable_depth)) {
+                printk("enable_irq(%u) unbalanced from %p\n", irq,
+                        __builtin_return_address(0));
+        } else if (!--desc->disable_depth) {
+                desc->probing = 0;
+                desc->chip->unmask(irq);
+
+                /*
+                 * If the interrupt is waiting to be processed,
+                 * try to re-run it.  We can't directly run it
+                 * from here since the caller might be in an
+                 * interrupt-protected region.
+                 */
+                if (desc->pending && list_empty(&desc->pend)) {
+                        desc->pending = 0;
+                        if (!desc->chip->retrigger ||
+                            desc->chip->retrigger(irq))
+                                list_add(&desc->pend, &irq_pending);
+                }
+        }
+        spin_unlock_irqrestore(&irq_controller_lock, flags);
+}
+EXPORT_SYMBOL(enable_irq);
+
+/*
+ * Enable wake on selected irq
+ */
+void enable_irq_wake(unsigned int irq)
+{
+        struct irqdesc *desc = irq_desc + irq;
+        unsigned long flags;
+
+        spin_lock_irqsave(&irq_controller_lock, flags);
+        if (desc->chip->wake)
+                desc->chip->wake(irq, 1);
+        spin_unlock_irqrestore(&irq_controller_lock, flags);
+}
+EXPORT_SYMBOL(enable_irq_wake);
+
+void disable_irq_wake(unsigned int irq)
+{
+        struct irqdesc *desc = irq_desc + irq;
+        unsigned long flags;
+
+        spin_lock_irqsave(&irq_controller_lock, flags);
+        if (desc->chip->wake)
+                desc->chip->wake(irq, 0);
+        spin_unlock_irqrestore(&irq_controller_lock, flags);
+}
+EXPORT_SYMBOL(disable_irq_wake);
+
+int show_interrupts(struct seq_file *p, void *v)
+{
+        int i = *(loff_t *) v, cpu;
+        struct irqaction * action;
+        unsigned long flags;
+
+        if (i == 0) {
+                char cpuname[12];
+
+                seq_printf(p, "    ");
+                for_each_present_cpu(cpu) {
+                        sprintf(cpuname, "CPU%d", cpu);
+                        seq_printf(p, " %10s", cpuname);
+                }
+                seq_putc(p, '\n');
+        }
+
+        if (i < NR_IRQS) {
+                spin_lock_irqsave(&irq_controller_lock, flags);
+                action = irq_desc[i].action;
+                if (!action)
+                        goto unlock;
+
+                seq_printf(p, "%3d: ", i);
+                for_each_present_cpu(cpu)
+                        seq_printf(p, "%10u ", kstat_cpu(cpu).irqs[i]);
+                seq_printf(p, "  %s", action->name);
+                for (action = action->next; action; action = action->next)
+                        seq_printf(p, ", %s", action->name);
+
+                seq_putc(p, '\n');
+unlock:
+                spin_unlock_irqrestore(&irq_controller_lock, flags);
+        } else if (i == NR_IRQS) {
+#ifdef CONFIG_ARCH_ACORN
+                show_fiq_list(p, v);
+#endif
+#ifdef CONFIG_SMP
+                show_ipi_list(p);
+#endif
+                seq_printf(p, "Err: %10lu\n", irq_err_count);
+        }
+        return 0;
+}
+
+/*
+ * IRQ lock detection.
+ *
+ * Hopefully, this should get us out of a few locked situations.
+ * However, it may take a while for this to happen, since we need
+ * a large number if IRQs to appear in the same jiffie with the
+ * same instruction pointer (or within 2 instructions).
+ */
+static int check_irq_lock(struct irqdesc *desc, int irq, struct pt_regs *regs)
+{
+        unsigned long instr_ptr = instruction_pointer(regs);
+
+        if (desc->lck_jif == jiffies &&
+            desc->lck_pc >= instr_ptr && desc->lck_pc < instr_ptr + 8) {
+                desc->lck_cnt += 1;
+
+                if (desc->lck_cnt > MAX_IRQ_CNT) {
+                        printk(KERN_ERR "IRQ LOCK: IRQ%d is locking the system, disabled\n", irq);
+                        return 1;
+                }
+        } else {
+                desc->lck_cnt = 0;
+                desc->lck_pc  = instruction_pointer(regs);
+                desc->lck_jif = jiffies;
+        }
+        return 0;
+}
+
+static void
+report_bad_irq(unsigned int irq, struct pt_regs *regs, struct irqdesc *desc, int ret)
+{
+        static int count = 100;
+        struct irqaction *action;
+
+        if (!count || noirqdebug)
+                return;
+
+        count--;
+
+        if (ret != IRQ_HANDLED && ret != IRQ_NONE) {
+                printk("irq%u: bogus retval mask %x\n", irq, ret);
+        } else {
+                printk("irq%u: nobody cared\n", irq);
+        }
+        show_regs(regs);
+        dump_stack();
+        printk(KERN_ERR "handlers:");
+        action = desc->action;
+        do {
+                printk("\n" KERN_ERR "[<%p>]", action->handler);
+                print_symbol(" (%s)", (unsigned long)action->handler);
+                action = action->next;
+        } while (action);
+        printk("\n");
+}
+
+static int
+__do_irq(unsigned int irq, struct irqaction *action, struct pt_regs *regs)
+{
+        unsigned int status;
+        int ret, retval = 0;
+
+        spin_unlock(&irq_controller_lock);
+
+        if (!(action->flags & SA_INTERRUPT))
+                local_irq_enable();
+
+        status = 0;
+        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);
+
+        spin_lock_irq(&irq_controller_lock);
+
+        return retval;
+}
+
+/*
+ * This is for software-decoded IRQs.  The caller is expected to
+ * handle the ack, clear, mask and unmask issues.
+ */
+void
+do_simple_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
+{
+        struct irqaction *action;
+        const unsigned int cpu = smp_processor_id();
+
+        desc->triggered = 1;
+
+        kstat_cpu(cpu).irqs[irq]++;
+
+        smp_set_running(desc);
+
+        action = desc->action;
+        if (action) {
+                int ret = __do_irq(irq, action, regs);
+                if (ret != IRQ_HANDLED)
+                        report_bad_irq(irq, regs, desc, ret);
+        }
+
+        smp_clear_running(desc);
+}
+
+/*
+ * Most edge-triggered IRQ implementations seem to take a broken
+ * approach to this.  Hence the complexity.
+ */
+void
+do_edge_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
+{
+        const unsigned int cpu = smp_processor_id();
+
+        desc->triggered = 1;
+
+        /*
+         * If we're currently running this IRQ, or its disabled,
+         * we shouldn't process the IRQ.  Instead, turn on the
+         * hardware masks.
+         */
+        if (unlikely(desc->running || desc->disable_depth))
+                goto running;
+
+        /*
+         * Acknowledge and clear the IRQ, but don't mask it.
+         */
+        desc->chip->ack(irq);
+
+        /*
+         * Mark the IRQ currently in progress.
+         */
+        desc->running = 1;
+
+        kstat_cpu(cpu).irqs[irq]++;
+
+        do {
+                struct irqaction *action;
+
+                action = desc->action;
+                if (!action)
+                        break;
+
+                if (desc->pending && !desc->disable_depth) {
+                        desc->pending = 0;
+                        desc->chip->unmask(irq);
+                }
+
+                __do_irq(irq, action, regs);
+        } while (desc->pending && !desc->disable_depth);
+
+        desc->running = 0;
+
+        /*
+         * If we were disabled or freed, shut down the handler.
+         */
+        if (likely(desc->action && !check_irq_lock(desc, irq, regs)))
+                return;
+
+ running:
+        /*
+         * We got another IRQ while this one was masked or
+         * currently running.  Delay it.
+         */
+        desc->pending = 1;
+        desc->chip->mask(irq);
+        desc->chip->ack(irq);
+}
+
+/*
+ * Level-based IRQ handler.  Nice and simple.
+ */
+void
+do_level_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
+{
+        struct irqaction *action;
+        const unsigned int cpu = smp_processor_id();
+
+        desc->triggered = 1;
+
+        /*
+         * Acknowledge, clear _AND_ disable the interrupt.
+         */
+        desc->chip->ack(irq);
+
+        if (likely(!desc->disable_depth)) {
+                kstat_cpu(cpu).irqs[irq]++;
+
+                smp_set_running(desc);
+
+                /*
+                 * Return with this interrupt masked if no action
+                 */
+                action = desc->action;
+                if (action) {
+                        int ret = __do_irq(irq, desc->action, regs);
+
+                        if (ret != IRQ_HANDLED)
+                                report_bad_irq(irq, regs, desc, ret);
+
+                        if (likely(!desc->disable_depth &&
+                                   !check_irq_lock(desc, irq, regs)))
+                                desc->chip->unmask(irq);
+                }
+
+                smp_clear_running(desc);
+        }
+}
+
+static void do_pending_irqs(struct pt_regs *regs)
+{
+        struct list_head head, *l, *n;
+
+        do {
+                struct irqdesc *desc;
+
+                /*
+                 * First, take the pending interrupts off the list.
+                 * The act of calling the handlers may add some IRQs
+                 * back onto the list.
+                 */
+                head = irq_pending;
+                INIT_LIST_HEAD(&irq_pending);
+                head.next->prev = &head;
+                head.prev->next = &head;
+
+                /*
+                 * Now run each entry.  We must delete it from our
+                 * list before calling the handler.
+                 */
+                list_for_each_safe(l, n, &head) {
+                        desc = list_entry(l, struct irqdesc, pend);
+                        list_del_init(&desc->pend);
+                        desc->handle(desc - irq_desc, desc, regs);
+                }
+
+                /*
+                 * The list must be empty.
+                 */
+                BUG_ON(!list_empty(&head));
+        } while (!list_empty(&irq_pending));
+}
+
+/*
+ * do_IRQ handles all hardware IRQ's.  Decoded IRQs should not
+ * come via this function.  Instead, they should provide their
+ * own 'handler'
+ */
+asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
+{
+        struct irqdesc *desc = irq_desc + irq;
+
+        /*
+         * Some hardware gives randomly wrong interrupts.  Rather
+         * than crashing, do something sensible.
+         */
+        if (irq >= NR_IRQS)
+                desc = &bad_irq_desc;
+
+        irq_enter();
+        spin_lock(&irq_controller_lock);
+        desc->handle(irq, desc, regs);
+
+        /*
+         * Now re-run any pending interrupts.
+         */
+        if (!list_empty(&irq_pending))
+                do_pending_irqs(regs);
+
+        irq_finish(irq);
+
+        spin_unlock(&irq_controller_lock);
+        irq_exit();
+}
+
+void __set_irq_handler(unsigned int irq, irq_handler_t handle, int is_chained)
+{
+        struct irqdesc *desc;
+        unsigned long flags;
+
+        if (irq >= NR_IRQS) {
+                printk(KERN_ERR "Trying to install handler for IRQ%d\n", irq);
+                return;
+        }
+
+        if (handle == NULL)
+                handle = do_bad_IRQ;
+
+        desc = irq_desc + irq;
+
+        if (is_chained && desc->chip == &bad_chip)
+                printk(KERN_WARNING "Trying to install chained handler for IRQ%d\n", irq);
+
+        spin_lock_irqsave(&irq_controller_lock, flags);
+        if (handle == do_bad_IRQ) {
+                desc->chip->mask(irq);
+                desc->chip->ack(irq);
+                desc->disable_depth = 1;
+        }
+        desc->handle = handle;
+        if (handle != do_bad_IRQ && is_chained) {
+                desc->valid = 0;
+                desc->probe_ok = 0;
+                desc->disable_depth = 0;
+                desc->chip->unmask(irq);
+        }
+        spin_unlock_irqrestore(&irq_controller_lock, flags);
+}
+
+void set_irq_chip(unsigned int irq, struct irqchip *chip)
+{
+        struct irqdesc *desc;
+        unsigned long flags;
+
+        if (irq >= NR_IRQS) {
+                printk(KERN_ERR "Trying to install chip for IRQ%d\n", irq);
+                return;
+        }
+
+        if (chip == NULL)
+                chip = &bad_chip;
+
+        desc = irq_desc + irq;
+        spin_lock_irqsave(&irq_controller_lock, flags);
+        desc->chip = chip;
+        spin_unlock_irqrestore(&irq_controller_lock, flags);
+}
+
+int set_irq_type(unsigned int irq, unsigned int type)
+{
+        struct irqdesc *desc;
+        unsigned long flags;
+        int ret = -ENXIO;
+
+        if (irq >= NR_IRQS) {
+                printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq);
+                return -ENODEV;
+        }
+
+        desc = irq_desc + irq;
+        if (desc->chip->type) {
+                spin_lock_irqsave(&irq_controller_lock, flags);
+                ret = desc->chip->type(irq, type);
+                spin_unlock_irqrestore(&irq_controller_lock, flags);
+        }
+
+        return ret;
+}
+EXPORT_SYMBOL(set_irq_type);
+
+void set_irq_flags(unsigned int irq, unsigned int iflags)
+{
+        struct irqdesc *desc;
+        unsigned long flags;
+
+        if (irq >= NR_IRQS) {
+                printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
+                return;
+        }
+
+        desc = irq_desc + irq;
+        spin_lock_irqsave(&irq_controller_lock, flags);
+        desc->valid = (iflags & IRQF_VALID) != 0;
+        desc->probe_ok = (iflags & IRQF_PROBE) != 0;
+        desc->noautoenable = (iflags & IRQF_NOAUTOEN) != 0;
+        spin_unlock_irqrestore(&irq_controller_lock, flags);
+}
+
+int setup_irq(unsigned int irq, struct irqaction *new)
+{
+        int shared = 0;
+        struct irqaction *old, **p;
+        unsigned long flags;
+        struct irqdesc *desc;
+
+        /*
+         * 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
+         */
+        desc = irq_desc + irq;
+        spin_lock_irqsave(&irq_controller_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(&irq_controller_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->probing = 0;
+                desc->running = 0;
+                desc->pending = 0;
+                desc->disable_depth = 1;
+                if (!desc->noautoenable) {
+                        desc->disable_depth = 0;
+                        desc->chip->unmask(irq);
+                }
+        }
+
+        spin_unlock_irqrestore(&irq_controller_lock, flags);
+        return 0;
+}
+
+/**
+ *      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 irq_flags, const char * devname, void *dev_id)
+{
+        unsigned long retval;
+        struct irqaction *action;
+
+        if (irq >= NR_IRQS || !irq_desc[irq].valid || !handler ||
+            (irq_flags & SA_SHIRQ && !dev_id))
+                return -EINVAL;
+
+        action = (struct irqaction *)kmalloc(sizeof(struct irqaction), GFP_KERNEL);
+        if (!action)
+                return -ENOMEM;
+
+        action->handler = handler;
+        action->flags = irq_flags;
+        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);
+
+/**
+ *      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.
+ *
+ *      This function must not be called from interrupt context.
+ */
+void free_irq(unsigned int irq, void *dev_id)
+{
+        struct irqaction * action, **p;
+        unsigned long flags;
+
+        if (irq >= NR_IRQS || !irq_desc[irq].valid) {
+                printk(KERN_ERR "Trying to free IRQ%d\n",irq);
+                dump_stack();
+                return;
+        }
+
+        spin_lock_irqsave(&irq_controller_lock, flags);
+        for (p = &irq_desc[irq].action; (action = *p) != NULL; p = &action->next) {
+                if (action->dev_id != dev_id)
+                        continue;
+
+                /* Found it - now free it */
+                *p = action->next;
+                break;
+        }
+        spin_unlock_irqrestore(&irq_controller_lock, flags);
+
+        if (!action) {
+                printk(KERN_ERR "Trying to free free IRQ%d\n",irq);
+                dump_stack();
+        } else {
+                synchronize_irq(irq);
+                kfree(action);
+        }
+}
+
+EXPORT_SYMBOL(free_irq);
+
+static DECLARE_MUTEX(probe_sem);
+
+/* Start the interrupt probing.  Unlike other architectures,
+ * we don't return a mask of interrupts from probe_irq_on,
+ * but return the number of interrupts enabled for the probe.
+ * The interrupts which have been enabled for probing is
+ * instead recorded in the irq_desc structure.
+ */
+unsigned long probe_irq_on(void)
+{
+        unsigned int i, irqs = 0;
+        unsigned long delay;
+
+        down(&probe_sem);
+
+        /*
+         * first snaffle up any unassigned but
+         * probe-able interrupts
+         */
+        spin_lock_irq(&irq_controller_lock);
+        for (i = 0; i < NR_IRQS; i++) {
+                if (!irq_desc[i].probe_ok || irq_desc[i].action)
+                        continue;
+
+                irq_desc[i].probing = 1;
+                irq_desc[i].triggered = 0;
+                if (irq_desc[i].chip->type)
+                        irq_desc[i].chip->type(i, IRQT_PROBE);
+                irq_desc[i].chip->unmask(i);
+                irqs += 1;
+        }
+        spin_unlock_irq(&irq_controller_lock);
+
+        /*
+         * wait for spurious interrupts to mask themselves out again
+         */
+        for (delay = jiffies + HZ/10; time_before(jiffies, delay); )
+                /* min 100ms delay */;
+
+        /*
+         * now filter out any obviously spurious interrupts
+         */
+        spin_lock_irq(&irq_controller_lock);
+        for (i = 0; i < NR_IRQS; i++) {
+                if (irq_desc[i].probing && irq_desc[i].triggered) {
+                        irq_desc[i].probing = 0;
+                        irqs -= 1;
+                }
+        }
+        spin_unlock_irq(&irq_controller_lock);
+
+        return irqs;
+}
+
+EXPORT_SYMBOL(probe_irq_on);
+
+unsigned int probe_irq_mask(unsigned long irqs)
+{
+        unsigned int mask = 0, i;
+
+        spin_lock_irq(&irq_controller_lock);
+        for (i = 0; i < 16 && i < NR_IRQS; i++)
+                if (irq_desc[i].probing && irq_desc[i].triggered)
+                        mask |= 1 << i;
+        spin_unlock_irq(&irq_controller_lock);
+
+        up(&probe_sem);
+
+        return mask;
+}
+EXPORT_SYMBOL(probe_irq_mask);
+
+/*
+ * Possible return values:
+ *  >= 0 - interrupt number
+ *    -1 - no interrupt/many interrupts
+ */
+int probe_irq_off(unsigned long irqs)
+{
+        unsigned int i;
+        int irq_found = NO_IRQ;
+
+        /*
+         * look at the interrupts, and find exactly one
+         * that we were probing has been triggered
+         */
+        spin_lock_irq(&irq_controller_lock);
+        for (i = 0; i < NR_IRQS; i++) {
+                if (irq_desc[i].probing &&
+                    irq_desc[i].triggered) {
+                        if (irq_found != NO_IRQ) {
+                                irq_found = NO_IRQ;
+                                goto out;
+                        }
+                        irq_found = i;
+                }
+        }
+
+        if (irq_found == -1)
+                irq_found = NO_IRQ;
+out:
+        spin_unlock_irq(&irq_controller_lock);
+
+        up(&probe_sem);
+
+        return irq_found;
+}
+
+EXPORT_SYMBOL(probe_irq_off);
+
+#ifdef CONFIG_SMP
+static void route_irq(struct irqdesc *desc, unsigned int irq, unsigned int cpu)
+{
+        pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", irq, desc->cpu, cpu);
+
+        spin_lock_irq(&irq_controller_lock);
+        desc->cpu = cpu;
+        desc->chip->set_cpu(desc, irq, cpu);
+        spin_unlock_irq(&irq_controller_lock);
+}
+
+#ifdef CONFIG_PROC_FS
+static int
+irq_affinity_read_proc(char *page, char **start, off_t off, int count,
+                       int *eof, void *data)
+{
+        struct irqdesc *desc = irq_desc + ((int)data);
+        int len = cpumask_scnprintf(page, count, desc->affinity);
+
+        if (count - len < 2)
+                return -EINVAL;
+        page[len++] = '\n';
+        page[len] = '\0';
+
+        return len;
+}
+
+static int
+irq_affinity_write_proc(struct file *file, const char __user *buffer,
+                        unsigned long count, void *data)
+{
+        unsigned int irq = (unsigned int)data;
+        struct irqdesc *desc = irq_desc + irq;
+        cpumask_t affinity, tmp;
+        int ret = -EIO;
+
+        if (!desc->chip->set_cpu)
+                goto out;
+
+        ret = cpumask_parse(buffer, count, affinity);
+        if (ret)
+                goto out;
+
+        cpus_and(tmp, affinity, cpu_online_map);
+        if (cpus_empty(tmp)) {
+                ret = -EINVAL;
+                goto out;
+        }
+
+        desc->affinity = affinity;
+        route_irq(desc, irq, first_cpu(tmp));
+        ret = count;
+
+ out:
+        return ret;
+}
+#endif
+#endif
+
+void __init init_irq_proc(void)
+{
+#if defined(CONFIG_SMP) && defined(CONFIG_PROC_FS)
+        struct proc_dir_entry *dir;
+        int irq;
+
+        dir = proc_mkdir("irq", 0);
+        if (!dir)
+                return;
+
+        for (irq = 0; irq < NR_IRQS; irq++) {
+                struct proc_dir_entry *entry;
+                struct irqdesc *desc;
+                char name[16];
+
+                desc = irq_desc + irq;
+                memset(name, 0, sizeof(name));
+                snprintf(name, sizeof(name) - 1, "%u", irq);
+
+                desc->procdir = proc_mkdir(name, dir);
+                if (!desc->procdir)
+                        continue;
+
+                entry = create_proc_entry("smp_affinity", 0600, desc->procdir);
+                if (entry) {
+                        entry->nlink = 1;
+                        entry->data = (void *)irq;
+                        entry->read_proc = irq_affinity_read_proc;
+                        entry->write_proc = irq_affinity_write_proc;
+                }
+        }
+#endif
+}
+
+void __init init_IRQ(void)
+{
+        struct irqdesc *desc;
+        extern void init_dma(void);
+        int irq;
+
+#ifdef CONFIG_SMP
+        bad_irq_desc.affinity = CPU_MASK_ALL;
+        bad_irq_desc.cpu = smp_processor_id();
+#endif
+
+        for (irq = 0, desc = irq_desc; irq < NR_IRQS; irq++, desc++) {
+                *desc = bad_irq_desc;
+                INIT_LIST_HEAD(&desc->pend);
+        }
+
+        init_arch_irq();
+        init_dma();
+}
+
+static int __init noirqdebug_setup(char *str)
+{
+        noirqdebug = 1;
+        return 1;
+}
+
+__setup("noirqdebug", noirqdebug_setup);