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 0000000..b6114f5
--- /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