aboutsummaryrefslogtreecommitdiff
path: root/arch/alpha/kernel/irq.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/alpha/kernel/irq.c
downloadlinux-stericsson-2.6.12-rc2.tar.gz
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!
Diffstat (limited to 'arch/alpha/kernel/irq.c')
-rw-r--r--arch/alpha/kernel/irq.c774
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