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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/arm26/kernel/irq.c
downloadconfigs-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.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/arm26/kernel/irq.c')
-rw-r--r--arch/arm26/kernel/irq.c716
1 files changed, 716 insertions, 0 deletions
diff --git a/arch/arm26/kernel/irq.c b/arch/arm26/kernel/irq.c
new file mode 100644
index 00000000000..f3cc1036e5b
--- /dev/null
+++ b/arch/arm26/kernel/irq.c
@@ -0,0 +1,716 @@
+/*
+ * linux/arch/arm/kernel/irq.c
+ *
+ * Copyright (C) 1992 Linus Torvalds
+ * Modifications for ARM processor Copyright (C) 1995-2000 Russell King.
+ * 'Borrowed' for ARM26 and (C) 2003 Ian Molton.
+ *
+ * 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/module.h>
+#include <linux/ptrace.h>
+#include <linux/kernel_stat.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/ioport.h>
+#include <linux/interrupt.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 <asm/irq.h>
+#include <asm/system.h>
+#include <asm/irqchip.h>
+
+//FIXME - this ought to be in a header IMO
+void __init arc_init_irq(void);
+
+/*
+ * 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.
+ *
+ * FIXME Maybe we ought to set a timer and re-enable the IRQ at a later time?
+ */
+#define MAX_IRQ_CNT 100000
+
+static volatile unsigned long irq_err_count;
+static DEFINE_SPINLOCK(irq_controller_lock);
+
+struct irqdesc irq_desc[NR_IRQS];
+
+/*
+ * Dummy mask/unmask handler
+ */
+void dummy_mask_unmask_irq(unsigned int irq)
+{
+}
+
+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,
+ .depth = 1,
+};
+
+/**
+ * disable_irq - disable an irq and wait for completion
+ * @irq: Interrupt to disable
+ *
+ * Disable the selected interrupt line. We do this lazily.
+ *
+ * This function may be called from IRQ context.
+ */
+void disable_irq(unsigned int irq)
+{
+ struct irqdesc *desc = irq_desc + irq;
+ unsigned long flags;
+ spin_lock_irqsave(&irq_controller_lock, flags);
+ if (!desc->depth++)
+ desc->enabled = 0;
+ spin_unlock_irqrestore(&irq_controller_lock, flags);
+}
+
+/**
+ * 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;
+ int pending = 0;
+
+ spin_lock_irqsave(&irq_controller_lock, flags);
+ if (unlikely(!desc->depth)) {
+ printk("enable_irq(%u) unbalanced from %p\n", irq,
+ __builtin_return_address(0)); //FIXME bum addresses reported - why?
+ } else if (!--desc->depth) {
+ desc->probing = 0;
+ desc->enabled = 1;
+ desc->chip->unmask(irq);
+ pending = desc->pending;
+ desc->pending = 0;
+ /*
+ * If the interrupt was waiting to be processed,
+ * retrigger it.
+ */
+ if (pending)
+ desc->chip->rerun(irq);
+ }
+ spin_unlock_irqrestore(&irq_controller_lock, flags);
+}
+
+int show_interrupts(struct seq_file *p, void *v)
+{
+ int i = *(loff_t *) v;
+ struct irqaction * action;
+
+ if (i < NR_IRQS) {
+ action = irq_desc[i].action;
+ if (!action)
+ continue;
+ seq_printf(p, "%3d: %10u ", i, kstat_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');
+ } else if (i == NR_IRQS) {
+ show_fiq_list(p, v);
+ 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
+__do_irq(unsigned int irq, struct irqaction *action, struct pt_regs *regs)
+{
+ unsigned int status;
+ int ret;
+
+ 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;
+ action = action->next;
+ } while (action);
+
+ if (status & SA_SAMPLE_RANDOM)
+ add_interrupt_randomness(irq);
+
+ spin_lock_irq(&irq_controller_lock);
+}
+
+/*
+ * 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 int cpu = smp_processor_id();
+
+ desc->triggered = 1;
+
+ kstat_cpu(cpu).irqs[irq]++;
+
+ action = desc->action;
+ if (action)
+ __do_irq(irq, desc->action, regs);
+}
+
+/*
+ * 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 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->enabled))
+ 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->enabled) {
+ desc->pending = 0;
+ desc->chip->unmask(irq);
+ }
+
+ __do_irq(irq, action, regs);
+ } while (desc->pending);
+
+ 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 int cpu = smp_processor_id();
+
+ desc->triggered = 1;
+
+ /*
+ * Acknowledge, clear _AND_ disable the interrupt.
+ */
+ desc->chip->ack(irq);
+
+ if (likely(desc->enabled)) {
+ kstat_cpu(cpu).irqs[irq]++;
+
+ /*
+ * Return with this interrupt masked if no action
+ */
+ action = desc->action;
+ if (action) {
+ __do_irq(irq, desc->action, regs);
+
+ if (likely(desc->enabled &&
+ !check_irq_lock(desc, irq, regs)))
+ desc->chip->unmask(irq);
+ }
+ }
+}
+
+/*
+ * 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(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);
+ 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->depth = 1;
+ desc->enabled = 0;
+ }
+ desc->handle = handle;
+ if (handle != do_bad_IRQ && is_chained) {
+ desc->valid = 0;
+ desc->probe_ok = 0;
+ desc->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;
+}
+
+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->depth = 1;
+ if (!desc->noautoenable) {
+ desc->depth = 0;
+ desc->enabled = 1;
+ 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
+ *
+ */
+
+//FIXME - handler used to return void - whats the significance of the change?
+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 may 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);
+#ifdef CONFIG_DEBUG_ERRORS
+ __backtrace();
+#endif
+ 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;
+ kfree(action);
+ goto out;
+ }
+ printk(KERN_ERR "Trying to free free IRQ%d\n",irq);
+#ifdef CONFIG_DEBUG_ERRORS
+ __backtrace();
+#endif
+out:
+ spin_unlock_irqrestore(&irq_controller_lock, flags);
+}
+
+EXPORT_SYMBOL(free_irq);
+
+/* 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;
+
+ /*
+ * 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);
+
+/*
+ * 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);
+
+ return irq_found;
+}
+
+EXPORT_SYMBOL(probe_irq_off);
+
+void __init init_irq_proc(void)
+{
+}
+
+void __init init_IRQ(void)
+{
+ struct irqdesc *desc;
+ extern void init_dma(void);
+ int irq;
+
+ for (irq = 0, desc = irq_desc; irq < NR_IRQS; irq++, desc++)
+ *desc = bad_irq_desc;
+
+ arc_init_irq();
+ init_dma();
+}