patch-2.4.6 linux/arch/mips/kernel/irq.c
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- Lines: 975
- Date:
Mon Jul 2 13:56:40 2001
- Orig file:
v2.4.5/linux/arch/mips/kernel/irq.c
- Orig date:
Fri Feb 9 11:29:44 2001
diff -u --recursive --new-file v2.4.5/linux/arch/mips/kernel/irq.c linux/arch/mips/kernel/irq.c
@@ -8,289 +8,367 @@
* Copyright (C) 1992 Linus Torvalds
* Copyright (C) 1994 - 2000 Ralf Baechle
*/
-#include <linux/config.h>
-#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/irq.h>
#include <linux/init.h>
-#include <linux/kernel_stat.h>
-#include <linux/module.h>
-#include <linux/signal.h>
-#include <linux/sched.h>
-#include <linux/types.h>
#include <linux/interrupt.h>
-#include <linux/ioport.h>
-#include <linux/timex.h>
+#include <linux/kernel_stat.h>
#include <linux/slab.h>
+#include <linux/mm.h>
#include <linux/random.h>
+#include <linux/sched.h>
-#include <asm/bitops.h>
-#include <asm/bootinfo.h>
-#include <asm/io.h>
-#include <asm/irq.h>
-#include <asm/mipsregs.h>
#include <asm/system.h>
-#include <asm/sni.h>
-#include <asm/nile4.h>
/*
- * Linux has a controller-independent x86 interrupt architecture.
- * every controller has a 'controller-template', that is used
- * by the main code to do the right thing. Each driver-visible
- * interrupt source is transparently wired to the apropriate
- * controller. Thus drivers need not be aware of the
- * interrupt-controller.
- *
- * Various interrupt controllers we handle: 8259 PIC, SMP IO-APIC,
- * PIIX4's internal 8259 PIC and SGI's Visual Workstation Cobalt (IO-)APIC.
- * (IO-APICs assumed to be messaging to Pentium local-APICs)
- *
- * the code is designed to be easily extended with new/different
- * interrupt controllers, without having to do assembly magic.
+ * Controller mappings for all interrupt sources:
*/
+irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned =
+ { [0 ... NR_IRQS-1] = { 0, &no_irq_type, NULL, 0, SPIN_LOCK_UNLOCKED}};
/*
- * This contains the irq mask for both 8259A irq controllers, it's an
- * int so we can deal with the third PIC in some systems like the RM300.
- * (XXX This is broken for big endian.)
+ * Special irq handlers.
*/
-static unsigned int cached_irq_mask = 0xffff;
-
-#define __byte(x,y) (((unsigned char *)&(y))[x])
-#define __word(x,y) (((unsigned short *)&(y))[x])
-#define __long(x,y) (((unsigned int *)&(y))[x])
-#define cached_21 (__byte(0,cached_irq_mask))
-#define cached_A1 (__byte(1,cached_irq_mask))
-
-unsigned long spurious_count = 0;
+void no_action(int cpl, void *dev_id, struct pt_regs *regs) { }
/*
- * (un)mask_irq, disable_irq() and enable_irq() only handle (E)ISA and
- * PCI devices. Other onboard hardware needs specific routines.
+ * Generic no controller code
*/
-static inline void mask_irq(unsigned int irq)
-{
- cached_irq_mask |= 1 << irq;
- if (irq & 8) {
- outb(cached_A1, 0xa1);
- } else {
- outb(cached_21, 0x21);
- }
-}
-static inline void unmask_irq(unsigned int irq)
-{
- cached_irq_mask &= ~(1 << irq);
- if (irq & 8) {
- outb(cached_A1, 0xa1);
- } else {
- outb(cached_21, 0x21);
- }
-}
-
-void i8259_disable_irq(unsigned int irq_nr)
-{
- unsigned long flags;
-
- save_and_cli(flags);
- mask_irq(irq_nr);
- restore_flags(flags);
-}
+static void enable_none(unsigned int irq) { }
+static unsigned int startup_none(unsigned int irq) { return 0; }
+static void disable_none(unsigned int irq) { }
+static void ack_none(unsigned int irq)
+{
+ /*
+ * 'what should we do if we get a hw irq event on an illegal vector'.
+ * each architecture has to answer this themselves, it doesnt deserve
+ * a generic callback i think.
+ */
+ printk("unexpected interrupt %d\n", irq);
+}
+
+/* startup is the same as "enable", shutdown is same as "disable" */
+#define shutdown_none disable_none
+#define end_none enable_none
+
+struct hw_interrupt_type no_irq_type = {
+ "none",
+ startup_none,
+ shutdown_none,
+ enable_none,
+ disable_none,
+ ack_none,
+ end_none
+};
-void i8259_enable_irq(unsigned int irq_nr)
-{
- unsigned long flags;
- save_and_cli(flags);
- unmask_irq(irq_nr);
- restore_flags(flags);
-}
+volatile unsigned long irq_err_count, spurious_count;
-static struct irqaction *irq_action[NR_IRQS] = {
- NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
- NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
- NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
- NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
- NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
- NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
- NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
- NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
-};
+/*
+ * Generic, controller-independent functions:
+ */
int get_irq_list(char *buf)
{
- int i, len = 0;
struct irqaction * action;
+ char *p = buf;
+ int i;
+
+ p += sprintf(p, " ");
+ for (i=0; i < 1 /*smp_num_cpus*/; i++)
+ p += sprintf(p, "CPU%d ", i);
+ *p++ = '\n';
- for (i = 0 ; i < 32 ; i++) {
- action = irq_action[i];
+ for (i = 0 ; i < NR_IRQS ; i++) {
+ action = irq_desc[i].action;
if (!action)
continue;
- len += sprintf(buf+len, "%2d: %8d %c %s",
- i, kstat.irqs[0][i],
- (action->flags & SA_INTERRUPT) ? '+' : ' ',
- action->name);
- for (action=action->next; action; action = action->next) {
- len += sprintf(buf+len, ",%s %s",
- (action->flags & SA_INTERRUPT) ? " +" : "",
- action->name);
- }
- len += sprintf(buf+len, "\n");
+ p += sprintf(p, "%3d: ",i);
+ p += sprintf(p, "%10u ", kstat_irqs(i));
+ p += sprintf(p, " %14s", irq_desc[i].handler->typename);
+ p += sprintf(p, " %s", action->name);
+
+ for (action=action->next; action; action = action->next)
+ p += sprintf(p, ", %s", action->name);
+ *p++ = '\n';
}
- return len;
-}
-
-static inline void i8259_mask_and_ack_irq(int irq)
-{
- cached_irq_mask |= 1 << irq;
-
- if (irq & 8) {
- inb(0xa1);
- outb(cached_A1, 0xa1);
- outb(0x62, 0x20); /* Specific EOI to cascade */
- outb(0x20, 0xa0);
- } else {
- inb(0x21);
- outb(cached_21, 0x21);
- outb(0x20, 0x20);
- }
+ p += sprintf(p, "ERR: %10lu\n", irq_err_count);
+ return p - buf;
}
-asmlinkage void i8259_do_irq(int irq, struct pt_regs *regs)
+/*
+ * This should really return information about whether
+ * we should do bottom half handling etc. Right now we
+ * end up _always_ checking the bottom half, which is a
+ * waste of time and is not what some drivers would
+ * prefer.
+ */
+int handle_IRQ_event(unsigned int irq, struct pt_regs * regs, struct irqaction * action)
{
- struct irqaction *action;
- int do_random, cpu;
-
- cpu = smp_processor_id();
- irq_enter(cpu);
+ int status;
+ int cpu = smp_processor_id();
- if (irq >= 16)
- goto out;
+ irq_enter(cpu, irq);
- i8259_mask_and_ack_irq(irq);
-
- kstat.irqs[cpu][irq]++;
-
- action = *(irq + irq_action);
- if (!action)
- goto out;
+ status = 1; /* Force the "do bottom halves" bit */
if (!(action->flags & SA_INTERRUPT))
__sti();
- action = *(irq + irq_action);
- do_random = 0;
- do {
- do_random |= action->flags;
+
+ do {
+ status |= action->flags;
action->handler(irq, action->dev_id, regs);
action = action->next;
- } while (action);
- if (do_random & SA_SAMPLE_RANDOM)
+ } while (action);
+ if (status & SA_SAMPLE_RANDOM)
add_interrupt_randomness(irq);
__cli();
- unmask_irq (irq);
-out:
- irq_exit(cpu);
+ irq_exit(cpu, irq);
+
+ return status;
}
/*
- * do_IRQ handles IRQ's that have been installed without the
- * SA_INTERRUPT flag: it uses the full signal-handling return
- * and runs with other interrupts enabled. All relatively slow
- * IRQ's should use this format: notably the keyboard/timer
- * routines.
+ * 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.
+ */
+
+/**
+ * disable_irq_nosync - disable an irq without waiting
+ * @irq: Interrupt to disable
+ *
+ * Disable the selected interrupt line. Disables of an interrupt
+ * stack. Unlike disable_irq(), this function does not ensure existing
+ * instances of the IRQ handler have completed before returning.
+ *
+ * This function may be called from IRQ context.
*/
-asmlinkage void do_IRQ(int irq, struct pt_regs * regs)
+
+void inline disable_irq_nosync(unsigned int irq)
{
- struct irqaction *action;
- int do_random, cpu;
-
- cpu = smp_processor_id();
- irq_enter(cpu);
- kstat.irqs[cpu][irq]++;
+ irq_desc_t *desc = irq_desc + irq;
+ unsigned long flags;
- action = *(irq + irq_action);
- if (action) {
- if (!(action->flags & SA_INTERRUPT))
- __sti();
- action = *(irq + irq_action);
- do_random = 0;
- do {
- do_random |= action->flags;
- action->handler(irq, action->dev_id, regs);
- action = action->next;
- } while (action);
- if (do_random & SA_SAMPLE_RANDOM)
- add_interrupt_randomness(irq);
- __cli();
+ spin_lock_irqsave(&desc->lock, flags);
+ if (!desc->depth++) {
+ desc->status |= IRQ_DISABLED;
+ desc->handler->disable(irq);
}
- irq_exit(cpu);
+ spin_unlock_irqrestore(&desc->lock, flags);
+}
- if (softirq_active(cpu)&softirq_mask(cpu))
- do_softirq();
+/**
+ * disable_irq - disable an irq and wait for completion
+ * @irq: Interrupt to disable
+ *
+ * Disable the selected interrupt line. Disables of an interrupt
+ * stack. That is for two disables you need two enables. This
+ * function 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)
+{
+ disable_irq_nosync(irq);
- /* unmasking and bottom half handling is done magically for us. */
+ if (!local_irq_count(smp_processor_id())) {
+ do {
+ barrier();
+ } while (irq_desc[irq].status & IRQ_INPROGRESS);
+ }
}
-int i8259_setup_irq(int irq, struct irqaction * new)
+/**
+ * enable_irq - enable interrupt handling on an irq
+ * @irq: Interrupt to enable
+ *
+ * Re-enables the processing of interrupts on this IRQ line
+ * providing no disable_irq calls are now in effect.
+ *
+ * This function may be called from IRQ context.
+ */
+
+void enable_irq(unsigned int irq)
{
- int shared = 0;
- struct irqaction *old, **p;
+ irq_desc_t *desc = irq_desc + irq;
unsigned long flags;
- p = irq_action + irq;
- if ((old = *p) != NULL) {
- /* Can't share interrupts unless both agree to */
- if (!(old->flags & new->flags & SA_SHIRQ))
- return -EBUSY;
+ 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("enable_irq(%u) unbalanced from %p\n", irq,
+ __builtin_return_address(0));
+ }
+ spin_unlock_irqrestore(&desc->lock, flags);
+}
- /* Can't share interrupts unless both are same type */
- if ((old->flags ^ new->flags) & SA_INTERRUPT)
- return -EBUSY;
+/*
+ * do_IRQ handles all normal device IRQ's (the special
+ * SMP cross-CPU interrupts have their own specific
+ * handlers).
+ */
+asmlinkage unsigned int do_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;
- /* add new interrupt at end of irq queue */
- do {
- p = &old->next;
- old = *p;
- } while (old);
- shared = 1;
+ kstat.irqs[cpu][irq]++;
+ spin_lock(&desc->lock);
+ 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 (new->flags & SA_SAMPLE_RANDOM)
- rand_initialize_irq(irq);
-
- save_and_cli(flags);
- *p = new;
+ /*
+ * 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;
- if (!shared) {
- if (is_i8259_irq(irq))
- unmask_irq(irq);
-#if CONFIG_DDB5074 /* This has no business here */
- else
- nile4_enable_irq(irq_to_nile4(irq));
-#endif
+ /*
+ * 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 do_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))
+ break;
+ desc->status &= ~IRQ_PENDING;
}
- restore_flags(flags);
- return 0;
+ 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);
+
+ if (softirq_active(cpu) & softirq_mask(cpu))
+ do_softirq();
+ return 1;
}
-/*
- * Request_interrupt and free_interrupt ``sort of'' handle interrupts of
- * non i8259 devices. They will have to be replaced by architecture
- * specific variants. For now we still use this as broken as it is because
- * it used to work ...
+/**
+ * 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,
void (*handler)(int, void *, struct pt_regs *),
- unsigned long irqflags, const char * devname, void *dev_id)
+ unsigned long irqflags,
+ const char * devname,
+ void *dev_id)
{
int retval;
struct irqaction * action;
- if (irq >= 32)
+#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) {
+ if (!dev_id)
+ printk("Bad boy: %s (at 0x%x) called us without a dev_id!\n", devname, (&irq)[-1]);
+ }
+#endif
+
+ if (irq >= NR_IRQS)
return -EINVAL;
if (!handler)
return -EINVAL;
- action = (struct irqaction *)kmalloc(sizeof(struct irqaction), GFP_KERNEL);
+ action = (struct irqaction *)
+ kmalloc(sizeof(struct irqaction), GFP_KERNEL);
if (!action)
return -ENOMEM;
@@ -301,107 +379,329 @@
action->next = NULL;
action->dev_id = dev_id;
- retval = i8259_setup_irq(irq, action);
-
+ retval = setup_irq(irq, action);
if (retval)
kfree(action);
return retval;
}
-
+
+/**
+ * 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. The function
+ * does not return until any executing interrupts for this IRQ
+ * have completed.
+ *
+ * This function may be called from interrupt context.
+ *
+ * Bugs: Attempting to free an irq in a handler for the same irq hangs
+ * the machine.
+ */
+
void free_irq(unsigned int irq, void *dev_id)
{
- struct irqaction * action, **p;
+ irq_desc_t *desc;
+ struct irqaction **p;
unsigned long flags;
- if (irq > 31) {
- printk("Trying to free IRQ%d\n",irq);
+ if (irq >= NR_IRQS)
return;
- }
- for (p = irq + irq_action; (action = *p) != NULL; p = &action->next) {
- if (action->dev_id != dev_id)
- continue;
- /* Found it - now free it */
- save_and_cli(flags);
- *p = action->next;
- if (!irq[irq_action])
- mask_irq(irq);
- restore_flags(flags);
- kfree(action);
+ 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 it - 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("Trying to free free IRQ%d\n",irq);
+ spin_unlock_irqrestore(&desc->lock,flags);
return;
}
- printk("Trying to free free IRQ%d\n",irq);
}
-unsigned long probe_irq_on (void)
+/*
+ * 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.
+ */
+
+static DECLARE_MUTEX(probe_sem);
+
+/**
+ * probe_irq_on - begin an interrupt autodetect
+ *
+ * Commence probing for an interrupt. The interrupts are scanned
+ * and a mask of potential interrupt lines is returned.
+ *
+ */
+
+unsigned long probe_irq_on(void)
{
- unsigned int i, irqs = 0;
+ unsigned int i;
+ irq_desc_t *desc;
+ unsigned long val;
unsigned long delay;
- /* first, enable any unassigned (E)ISA irqs */
- for (i = 15; i > 0; i--) {
- if (!irq_action[i]) {
- i8259_enable_irq(i);
- irqs |= (1 << i);
+ down(&probe_sem);
+ /*
+ * 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 */ synchronize_irq();
+
+ /*
+ * enable any unassigned irqs
+ * (we must startup again here because if a longstanding irq
+ * happened in the previous stage, it may have masked itself)
+ */
+ 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 mask themselves out again */
- for (delay = jiffies + HZ/10; time_before(jiffies, delay); )
- /* about 100ms delay */;
+ /*
+ * Wait for spurious interrupts to trigger
+ */
+ for (delay = jiffies + HZ/10; time_after(delay, jiffies); )
+ /* about 100ms delay */ synchronize_irq();
+
+ /*
+ * 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);
+ }
- /* now filter out any obviously spurious interrupts */
- return irqs & ~cached_irq_mask;
+ return val;
}
-int probe_irq_off (unsigned long irqs)
+/*
+ * Return a mask of triggered interrupts (this
+ * can handle only legacy ISA interrupts).
+ */
+
+/**
+ * probe_irq_mask - scan a bitmap of interrupt lines
+ * @val: mask of interrupts to consider
+ *
+ * Scan the ISA bus interrupt lines and return a bitmap of
+ * active interrupts. The interrupt probe logic state is then
+ * returned to its previous value.
+ *
+ * Note: we need to scan all the irq's even though we will
+ * only return ISA irq numbers - just so that we reset them
+ * all to a known state.
+ */
+unsigned int probe_irq_mask(unsigned long val)
{
- unsigned int i;
+ int i;
+ unsigned int mask;
-#ifdef DEBUG
- printk("probe_irq_off: irqs=0x%04x irqmask=0x%04x\n", irqs, irqmask);
-#endif
- irqs &= cached_irq_mask;
- if (!irqs)
- return 0;
- i = ffz(~irqs);
- if (irqs != (irqs & (1 << i)))
- i = -i;
- return i;
+ 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) {
+ if (i < 16 && !(status & IRQ_WAITING))
+ mask |= 1 << i;
+
+ desc->status = status & ~IRQ_AUTODETECT;
+ desc->handler->shutdown(i);
+ }
+ spin_unlock_irq(&desc->lock);
+ }
+ up(&probe_sem);
+
+ return mask & val;
}
-int (*irq_cannonicalize)(int irq);
+/*
+ * Return the one interrupt that triggered (this can
+ * handle any interrupt source).
+ */
-static int i8259_irq_cannonicalize(int irq)
+/**
+ * probe_irq_off - end an interrupt autodetect
+ * @val: mask of potential interrupts (unused)
+ *
+ * Scans the unused interrupt lines and returns the line which
+ * appears to have triggered the interrupt. If no interrupt was
+ * found then zero is returned. If more than one interrupt is
+ * found then minus the first candidate is returned to indicate
+ * their is doubt.
+ *
+ * The interrupt probe logic state is returned to its previous
+ * value.
+ *
+ * BUGS: When used in a module (which arguably shouldnt happen)
+ * nothing prevents two IRQ probe callers from overlapping. The
+ * results of this are non-optimal.
+ */
+
+int probe_irq_off(unsigned long val)
{
- return ((irq == 2) ? 9 : irq);
+ 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);
+ }
+ up(&probe_sem);
+
+ if (nr_irqs > 1)
+ irq_found = -irq_found;
+ return irq_found;
}
-void __init i8259_init(void)
+/* this was setup_x86_irq but it seems pretty generic */
+int setup_irq(unsigned int irq, struct irqaction * new)
{
- /* Init master interrupt controller */
- outb(0x11, 0x20); /* Start init sequence */
- outb(0x00, 0x21); /* Vector base */
- outb(0x04, 0x21); /* edge tiggered, Cascade (slave) on IRQ2 */
- outb(0x01, 0x21); /* Select 8086 mode */
- outb(0xff, 0x21); /* Mask all */
-
- /* Init slave interrupt controller */
- outb(0x11, 0xa0); /* Start init sequence */
- outb(0x08, 0xa1); /* Vector base */
- outb(0x02, 0xa1); /* edge triggered, Cascade (slave) on IRQ2 */
- outb(0x01, 0xa1); /* Select 8086 mode */
- outb(0xff, 0xa1); /* Mask all */
+ int shared = 0;
+ unsigned long flags;
+ struct irqaction *old, **p;
+ irq_desc_t *desc = irq_desc + irq;
+
+ /*
+ * 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);
+ }
- outb(cached_A1, 0xa1);
- outb(cached_21, 0x21);
+ /*
+ * 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);
+ desc->handler->startup(irq);
+ }
+ spin_unlock_irqrestore(&desc->lock,flags);
+
+ /* register_irq_proc(irq); */
+ return 0;
}
-void __init init_IRQ(void)
+void __init init_generic_irq(void)
{
- irq_cannonicalize = i8259_irq_cannonicalize;
- /* i8259_init(); */
- irq_setup();
-}
+ int i;
-EXPORT_SYMBOL(irq_cannonicalize);
+ for (i = 0; i < NR_IRQS; i++) {
+ irq_desc[i].status = IRQ_DISABLED;
+ irq_desc[i].action = NULL;
+ irq_desc[i].depth = 1;
+ irq_desc[i].handler = &no_irq_type;
+ }
+}
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)