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/arch/alpha/kernel/irq.c

https://bitbucket.org/evzijst/gittest
C | 774 lines | 520 code | 110 blank | 144 comment | 88 complexity | 7ce0f8f582f9f71cf636907d3b627574 MD5 | raw file
  1/*
  2 *	linux/arch/alpha/kernel/irq.c
  3 *
  4 *	Copyright (C) 1995 Linus Torvalds
  5 *
  6 * This file contains the code used by various IRQ handling routines:
  7 * asking for different IRQ's should be done through these routines
  8 * instead of just grabbing them. Thus setups with different IRQ numbers
  9 * shouldn't result in any weird surprises, and installing new handlers
 10 * should be easier.
 11 */
 12
 13#include <linux/config.h>
 14#include <linux/kernel.h>
 15#include <linux/module.h>
 16#include <linux/errno.h>
 17#include <linux/kernel_stat.h>
 18#include <linux/signal.h>
 19#include <linux/sched.h>
 20#include <linux/ptrace.h>
 21#include <linux/interrupt.h>
 22#include <linux/slab.h>
 23#include <linux/random.h>
 24#include <linux/init.h>
 25#include <linux/irq.h>
 26#include <linux/proc_fs.h>
 27#include <linux/seq_file.h>
 28#include <linux/profile.h>
 29#include <linux/bitops.h>
 30
 31#include <asm/system.h>
 32#include <asm/io.h>
 33#include <asm/uaccess.h>
 34
 35/*
 36 * Controller mappings for all interrupt sources:
 37 */
 38irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned = {
 39	[0 ... NR_IRQS-1] = {
 40		.handler = &no_irq_type,
 41		.lock = SPIN_LOCK_UNLOCKED
 42	}
 43};
 44
 45static void register_irq_proc(unsigned int irq);
 46
 47volatile unsigned long irq_err_count;
 48
 49/*
 50 * Special irq handlers.
 51 */
 52
 53irqreturn_t no_action(int cpl, void *dev_id, struct pt_regs *regs)
 54{
 55	return IRQ_NONE;
 56}
 57
 58/*
 59 * Generic no controller code
 60 */
 61
 62static void no_irq_enable_disable(unsigned int irq) { }
 63static unsigned int no_irq_startup(unsigned int irq) { return 0; }
 64
 65static void
 66no_irq_ack(unsigned int irq)
 67{
 68	irq_err_count++;
 69	printk(KERN_CRIT "Unexpected IRQ trap at vector %u\n", irq);
 70}
 71
 72struct hw_interrupt_type no_irq_type = {
 73	.typename	= "none",
 74	.startup	= no_irq_startup,
 75	.shutdown	= no_irq_enable_disable,
 76	.enable		= no_irq_enable_disable,
 77	.disable	= no_irq_enable_disable,
 78	.ack		= no_irq_ack,
 79	.end		= no_irq_enable_disable,
 80};
 81
 82int
 83handle_IRQ_event(unsigned int irq, struct pt_regs *regs,
 84		 struct irqaction *action)
 85{
 86	int status = 1;	/* Force the "do bottom halves" bit */
 87	int ret;
 88
 89	do {
 90		if (!(action->flags & SA_INTERRUPT))
 91			local_irq_enable();
 92		else
 93			local_irq_disable();
 94
 95		ret = action->handler(irq, action->dev_id, regs);
 96		if (ret == IRQ_HANDLED)
 97			status |= action->flags;
 98		action = action->next;
 99	} while (action);
100	if (status & SA_SAMPLE_RANDOM)
101		add_interrupt_randomness(irq);
102	local_irq_disable();
103
104	return status;
105}
106
107/*
108 * Generic enable/disable code: this just calls
109 * down into the PIC-specific version for the actual
110 * hardware disable after having gotten the irq
111 * controller lock. 
112 */
113void inline
114disable_irq_nosync(unsigned int irq)
115{
116	irq_desc_t *desc = irq_desc + irq;
117	unsigned long flags;
118
119	spin_lock_irqsave(&desc->lock, flags);
120	if (!desc->depth++) {
121		desc->status |= IRQ_DISABLED;
122		desc->handler->disable(irq);
123	}
124	spin_unlock_irqrestore(&desc->lock, flags);
125}
126
127/*
128 * Synchronous version of the above, making sure the IRQ is
129 * no longer running on any other IRQ..
130 */
131void
132disable_irq(unsigned int irq)
133{
134	disable_irq_nosync(irq);
135	synchronize_irq(irq);
136}
137
138void
139enable_irq(unsigned int irq)
140{
141	irq_desc_t *desc = irq_desc + irq;
142	unsigned long flags;
143
144	spin_lock_irqsave(&desc->lock, flags);
145	switch (desc->depth) {
146	case 1: {
147		unsigned int status = desc->status & ~IRQ_DISABLED;
148		desc->status = status;
149		if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) {
150			desc->status = status | IRQ_REPLAY;
151			hw_resend_irq(desc->handler,irq);
152		}
153		desc->handler->enable(irq);
154		/* fall-through */
155	}
156	default:
157		desc->depth--;
158		break;
159	case 0:
160		printk(KERN_ERR "enable_irq() unbalanced from %p\n",
161		       __builtin_return_address(0));
162	}
163	spin_unlock_irqrestore(&desc->lock, flags);
164}
165
166int
167setup_irq(unsigned int irq, struct irqaction * new)
168{
169	int shared = 0;
170	struct irqaction *old, **p;
171	unsigned long flags;
172	irq_desc_t *desc = irq_desc + irq;
173
174        if (desc->handler == &no_irq_type)
175		return -ENOSYS;
176
177	/*
178	 * Some drivers like serial.c use request_irq() heavily,
179	 * so we have to be careful not to interfere with a
180	 * running system.
181	 */
182	if (new->flags & SA_SAMPLE_RANDOM) {
183		/*
184		 * This function might sleep, we want to call it first,
185		 * outside of the atomic block.
186		 * Yes, this might clear the entropy pool if the wrong
187		 * driver is attempted to be loaded, without actually
188		 * installing a new handler, but is this really a problem,
189		 * only the sysadmin is able to do this.
190		 */
191		rand_initialize_irq(irq);
192	}
193
194	/*
195	 * The following block of code has to be executed atomically
196	 */
197	spin_lock_irqsave(&desc->lock,flags);
198	p = &desc->action;
199	if ((old = *p) != NULL) {
200		/* Can't share interrupts unless both agree to */
201		if (!(old->flags & new->flags & SA_SHIRQ)) {
202			spin_unlock_irqrestore(&desc->lock,flags);
203			return -EBUSY;
204		}
205
206		/* add new interrupt at end of irq queue */
207		do {
208			p = &old->next;
209			old = *p;
210		} while (old);
211		shared = 1;
212	}
213
214	*p = new;
215
216	if (!shared) {
217		desc->depth = 0;
218		desc->status &=
219		    ~(IRQ_DISABLED|IRQ_AUTODETECT|IRQ_WAITING|IRQ_INPROGRESS);
220		desc->handler->startup(irq);
221	}
222	spin_unlock_irqrestore(&desc->lock,flags);
223
224	return 0;
225}
226
227static struct proc_dir_entry * root_irq_dir;
228static struct proc_dir_entry * irq_dir[NR_IRQS];
229
230#ifdef CONFIG_SMP 
231static struct proc_dir_entry * smp_affinity_entry[NR_IRQS];
232static char irq_user_affinity[NR_IRQS];
233static cpumask_t irq_affinity[NR_IRQS] = { [0 ... NR_IRQS-1] = CPU_MASK_ALL };
234
235static void
236select_smp_affinity(int irq)
237{
238	static int last_cpu;
239	int cpu = last_cpu + 1;
240
241	if (! irq_desc[irq].handler->set_affinity || irq_user_affinity[irq])
242		return;
243
244	while (!cpu_possible(cpu))
245		cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
246	last_cpu = cpu;
247
248	irq_affinity[irq] = cpumask_of_cpu(cpu);
249	irq_desc[irq].handler->set_affinity(irq, cpumask_of_cpu(cpu));
250}
251
252static int
253irq_affinity_read_proc (char *page, char **start, off_t off,
254			int count, int *eof, void *data)
255{
256	int len = cpumask_scnprintf(page, count, irq_affinity[(long)data]);
257	if (count - len < 2)
258		return -EINVAL;
259	len += sprintf(page + len, "\n");
260	return len;
261}
262
263static int
264irq_affinity_write_proc(struct file *file, const char __user *buffer,
265			unsigned long count, void *data)
266{
267	int irq = (long) data, full_count = count, err;
268	cpumask_t new_value;
269
270	if (!irq_desc[irq].handler->set_affinity)
271		return -EIO;
272
273	err = cpumask_parse(buffer, count, new_value);
274
275	/* The special value 0 means release control of the
276	   affinity to kernel.  */
277	cpus_and(new_value, new_value, cpu_online_map);
278	if (cpus_empty(new_value)) {
279		irq_user_affinity[irq] = 0;
280		select_smp_affinity(irq);
281	}
282	/* Do not allow disabling IRQs completely - it's a too easy
283	   way to make the system unusable accidentally :-) At least
284	   one online CPU still has to be targeted.  */
285	else {
286		irq_affinity[irq] = new_value;
287		irq_user_affinity[irq] = 1;
288		irq_desc[irq].handler->set_affinity(irq, new_value);
289	}
290
291	return full_count;
292}
293
294#endif /* CONFIG_SMP */
295
296#define MAX_NAMELEN 10
297
298static void
299register_irq_proc (unsigned int irq)
300{
301	char name [MAX_NAMELEN];
302
303	if (!root_irq_dir || (irq_desc[irq].handler == &no_irq_type) ||
304	    irq_dir[irq])
305		return;
306
307	memset(name, 0, MAX_NAMELEN);
308	sprintf(name, "%d", irq);
309
310	/* create /proc/irq/1234 */
311	irq_dir[irq] = proc_mkdir(name, root_irq_dir);
312
313#ifdef CONFIG_SMP 
314	if (irq_desc[irq].handler->set_affinity) {
315		struct proc_dir_entry *entry;
316		/* create /proc/irq/1234/smp_affinity */
317		entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);
318
319		if (entry) {
320			entry->nlink = 1;
321			entry->data = (void *)(long)irq;
322			entry->read_proc = irq_affinity_read_proc;
323			entry->write_proc = irq_affinity_write_proc;
324		}
325
326		smp_affinity_entry[irq] = entry;
327	}
328#endif
329}
330
331void
332init_irq_proc (void)
333{
334	int i;
335
336	/* create /proc/irq */
337	root_irq_dir = proc_mkdir("irq", NULL);
338
339#ifdef CONFIG_SMP 
340	/* create /proc/irq/prof_cpu_mask */
341	create_prof_cpu_mask(root_irq_dir);
342#endif
343
344	/*
345	 * Create entries for all existing IRQs.
346	 */
347	for (i = 0; i < ACTUAL_NR_IRQS; i++) {
348		if (irq_desc[i].handler == &no_irq_type)
349			continue;
350		register_irq_proc(i);
351	}
352}
353
354int
355request_irq(unsigned int irq, irqreturn_t (*handler)(int, void *, struct pt_regs *),
356	    unsigned long irqflags, const char * devname, void *dev_id)
357{
358	int retval;
359	struct irqaction * action;
360
361	if (irq >= ACTUAL_NR_IRQS)
362		return -EINVAL;
363	if (!handler)
364		return -EINVAL;
365
366#if 1
367	/*
368	 * Sanity-check: shared interrupts should REALLY pass in
369	 * a real dev-ID, otherwise we'll have trouble later trying
370	 * to figure out which interrupt is which (messes up the
371	 * interrupt freeing logic etc).
372	 */
373	if ((irqflags & SA_SHIRQ) && !dev_id) {
374		printk(KERN_ERR
375		       "Bad boy: %s (at %p) called us without a dev_id!\n",
376		       devname, __builtin_return_address(0));
377	}
378#endif
379
380	action = (struct irqaction *)
381			kmalloc(sizeof(struct irqaction), GFP_KERNEL);
382	if (!action)
383		return -ENOMEM;
384
385	action->handler = handler;
386	action->flags = irqflags;
387	cpus_clear(action->mask);
388	action->name = devname;
389	action->next = NULL;
390	action->dev_id = dev_id;
391
392#ifdef CONFIG_SMP
393	select_smp_affinity(irq);
394#endif
395
396	retval = setup_irq(irq, action);
397	if (retval)
398		kfree(action);
399	return retval;
400}
401
402EXPORT_SYMBOL(request_irq);
403
404void
405free_irq(unsigned int irq, void *dev_id)
406{
407	irq_desc_t *desc;
408	struct irqaction **p;
409	unsigned long flags;
410
411	if (irq >= ACTUAL_NR_IRQS) {
412		printk(KERN_CRIT "Trying to free IRQ%d\n", irq);
413		return;
414	}
415
416	desc = irq_desc + irq;
417	spin_lock_irqsave(&desc->lock,flags);
418	p = &desc->action;
419	for (;;) {
420		struct irqaction * action = *p;
421		if (action) {
422			struct irqaction **pp = p;
423			p = &action->next;
424			if (action->dev_id != dev_id)
425				continue;
426
427			/* Found - now remove it from the list of entries.  */
428			*pp = action->next;
429			if (!desc->action) {
430				desc->status |= IRQ_DISABLED;
431				desc->handler->shutdown(irq);
432			}
433			spin_unlock_irqrestore(&desc->lock,flags);
434
435#ifdef CONFIG_SMP
436			/* Wait to make sure it's not being used on
437			   another CPU.  */
438			while (desc->status & IRQ_INPROGRESS)
439				barrier();
440#endif
441			kfree(action);
442			return;
443		}
444		printk(KERN_ERR "Trying to free free IRQ%d\n",irq);
445		spin_unlock_irqrestore(&desc->lock,flags);
446		return;
447	}
448}
449
450EXPORT_SYMBOL(free_irq);
451
452int
453show_interrupts(struct seq_file *p, void *v)
454{
455#ifdef CONFIG_SMP
456	int j;
457#endif
458	int i = *(loff_t *) v;
459	struct irqaction * action;
460	unsigned long flags;
461
462#ifdef CONFIG_SMP
463	if (i == 0) {
464		seq_puts(p, "           ");
465		for (i = 0; i < NR_CPUS; i++)
466			if (cpu_online(i))
467				seq_printf(p, "CPU%d       ", i);
468		seq_putc(p, '\n');
469	}
470#endif
471
472	if (i < ACTUAL_NR_IRQS) {
473		spin_lock_irqsave(&irq_desc[i].lock, flags);
474		action = irq_desc[i].action;
475		if (!action) 
476			goto unlock;
477		seq_printf(p, "%3d: ",i);
478#ifndef CONFIG_SMP
479		seq_printf(p, "%10u ", kstat_irqs(i));
480#else
481		for (j = 0; j < NR_CPUS; j++)
482			if (cpu_online(j))
483				seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
484#endif
485		seq_printf(p, " %14s", irq_desc[i].handler->typename);
486		seq_printf(p, "  %c%s",
487			(action->flags & SA_INTERRUPT)?'+':' ',
488			action->name);
489
490		for (action=action->next; action; action = action->next) {
491			seq_printf(p, ", %c%s",
492				  (action->flags & SA_INTERRUPT)?'+':' ',
493				   action->name);
494		}
495
496		seq_putc(p, '\n');
497unlock:
498		spin_unlock_irqrestore(&irq_desc[i].lock, flags);
499	} else if (i == ACTUAL_NR_IRQS) {
500#ifdef CONFIG_SMP
501		seq_puts(p, "IPI: ");
502		for (i = 0; i < NR_CPUS; i++)
503			if (cpu_online(i))
504				seq_printf(p, "%10lu ", cpu_data[i].ipi_count);
505		seq_putc(p, '\n');
506#endif
507		seq_printf(p, "ERR: %10lu\n", irq_err_count);
508	}
509	return 0;
510}
511
512
513/*
514 * handle_irq handles all normal device IRQ's (the special
515 * SMP cross-CPU interrupts have their own specific
516 * handlers).
517 */
518
519#define MAX_ILLEGAL_IRQS 16
520
521void
522handle_irq(int irq, struct pt_regs * regs)
523{	
524	/* 
525	 * We ack quickly, we don't want the irq controller
526	 * thinking we're snobs just because some other CPU has
527	 * disabled global interrupts (we have already done the
528	 * INT_ACK cycles, it's too late to try to pretend to the
529	 * controller that we aren't taking the interrupt).
530	 *
531	 * 0 return value means that this irq is already being
532	 * handled by some other CPU. (or is disabled)
533	 */
534	int cpu = smp_processor_id();
535	irq_desc_t *desc = irq_desc + irq;
536	struct irqaction * action;
537	unsigned int status;
538	static unsigned int illegal_count=0;
539	
540	if ((unsigned) irq > ACTUAL_NR_IRQS && illegal_count < MAX_ILLEGAL_IRQS ) {
541		irq_err_count++;
542		illegal_count++;
543		printk(KERN_CRIT "device_interrupt: invalid interrupt %d\n",
544		       irq);
545		return;
546	}
547
548	irq_enter();
549	kstat_cpu(cpu).irqs[irq]++;
550	spin_lock_irq(&desc->lock); /* mask also the higher prio events */
551	desc->handler->ack(irq);
552	/*
553	 * REPLAY is when Linux resends an IRQ that was dropped earlier.
554	 * WAITING is used by probe to mark irqs that are being tested.
555	 */
556	status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
557	status |= IRQ_PENDING; /* we _want_ to handle it */
558
559	/*
560	 * If the IRQ is disabled for whatever reason, we cannot
561	 * use the action we have.
562	 */
563	action = NULL;
564	if (!(status & (IRQ_DISABLED | IRQ_INPROGRESS))) {
565		action = desc->action;
566		status &= ~IRQ_PENDING; /* we commit to handling */
567		status |= IRQ_INPROGRESS; /* we are handling it */
568	}
569	desc->status = status;
570
571	/*
572	 * If there is no IRQ handler or it was disabled, exit early.
573	 * Since we set PENDING, if another processor is handling
574	 * a different instance of this same irq, the other processor
575	 * will take care of it.
576	 */
577	if (!action)
578		goto out;
579
580	/*
581	 * Edge triggered interrupts need to remember pending events.
582	 * This applies to any hw interrupts that allow a second
583	 * instance of the same irq to arrive while we are in handle_irq
584	 * or in the handler. But the code here only handles the _second_
585	 * instance of the irq, not the third or fourth. So it is mostly
586	 * useful for irq hardware that does not mask cleanly in an
587	 * SMP environment.
588	 */
589	for (;;) {
590		spin_unlock(&desc->lock);
591		handle_IRQ_event(irq, regs, action);
592		spin_lock(&desc->lock);
593		
594		if (!(desc->status & IRQ_PENDING)
595		    || (desc->status & IRQ_LEVEL))
596			break;
597		desc->status &= ~IRQ_PENDING;
598	}
599	desc->status &= ~IRQ_INPROGRESS;
600out:
601	/*
602	 * The ->end() handler has to deal with interrupts which got
603	 * disabled while the handler was running.
604	 */
605	desc->handler->end(irq);
606	spin_unlock(&desc->lock);
607
608	irq_exit();
609}
610
611/*
612 * IRQ autodetection code..
613 *
614 * This depends on the fact that any interrupt that
615 * comes in on to an unassigned handler will get stuck
616 * with "IRQ_WAITING" cleared and the interrupt
617 * disabled.
618 */
619unsigned long
620probe_irq_on(void)
621{
622	int i;
623	irq_desc_t *desc;
624	unsigned long delay;
625	unsigned long val;
626
627	/* Something may have generated an irq long ago and we want to
628	   flush such a longstanding irq before considering it as spurious. */
629	for (i = NR_IRQS-1; i >= 0; i--) {
630		desc = irq_desc + i;
631
632		spin_lock_irq(&desc->lock);
633		if (!irq_desc[i].action) 
634			irq_desc[i].handler->startup(i);
635		spin_unlock_irq(&desc->lock);
636	}
637
638	/* Wait for longstanding interrupts to trigger. */
639	for (delay = jiffies + HZ/50; time_after(delay, jiffies); )
640		/* about 20ms delay */ barrier();
641
642	/* enable any unassigned irqs (we must startup again here because
643	   if a longstanding irq happened in the previous stage, it may have
644	   masked itself) first, enable any unassigned irqs. */
645	for (i = NR_IRQS-1; i >= 0; i--) {
646		desc = irq_desc + i;
647
648		spin_lock_irq(&desc->lock);
649		if (!desc->action) {
650			desc->status |= IRQ_AUTODETECT | IRQ_WAITING;
651			if (desc->handler->startup(i))
652				desc->status |= IRQ_PENDING;
653		}
654		spin_unlock_irq(&desc->lock);
655	}
656
657	/*
658	 * Wait for spurious interrupts to trigger
659	 */
660	for (delay = jiffies + HZ/10; time_after(delay, jiffies); )
661		/* about 100ms delay */ barrier();
662
663	/*
664	 * Now filter out any obviously spurious interrupts
665	 */
666	val = 0;
667	for (i=0; i<NR_IRQS; i++) {
668		irq_desc_t *desc = irq_desc + i;
669		unsigned int status;
670
671		spin_lock_irq(&desc->lock);
672		status = desc->status;
673
674		if (status & IRQ_AUTODETECT) {
675			/* It triggered already - consider it spurious. */
676			if (!(status & IRQ_WAITING)) {
677				desc->status = status & ~IRQ_AUTODETECT;
678				desc->handler->shutdown(i);
679			} else
680				if (i < 32)
681					val |= 1 << i;
682		}
683		spin_unlock_irq(&desc->lock);
684	}
685
686	return val;
687}
688
689EXPORT_SYMBOL(probe_irq_on);
690
691/*
692 * Return a mask of triggered interrupts (this
693 * can handle only legacy ISA interrupts).
694 */
695unsigned int
696probe_irq_mask(unsigned long val)
697{
698	int i;
699	unsigned int mask;
700
701	mask = 0;
702	for (i = 0; i < NR_IRQS; i++) {
703		irq_desc_t *desc = irq_desc + i;
704		unsigned int status;
705
706		spin_lock_irq(&desc->lock);
707		status = desc->status;
708
709		if (status & IRQ_AUTODETECT) {
710			/* We only react to ISA interrupts */
711			if (!(status & IRQ_WAITING)) {
712				if (i < 16)
713					mask |= 1 << i;
714			}
715
716			desc->status = status & ~IRQ_AUTODETECT;
717			desc->handler->shutdown(i);
718		}
719		spin_unlock_irq(&desc->lock);
720	}
721
722	return mask & val;
723}
724
725/*
726 * Get the result of the IRQ probe.. A negative result means that
727 * we have several candidates (but we return the lowest-numbered
728 * one).
729 */
730
731int
732probe_irq_off(unsigned long val)
733{
734	int i, irq_found, nr_irqs;
735
736	nr_irqs = 0;
737	irq_found = 0;
738	for (i=0; i<NR_IRQS; i++) {
739		irq_desc_t *desc = irq_desc + i;
740		unsigned int status;
741
742		spin_lock_irq(&desc->lock);
743		status = desc->status;
744
745		if (status & IRQ_AUTODETECT) {
746			if (!(status & IRQ_WAITING)) {
747				if (!nr_irqs)
748					irq_found = i;
749				nr_irqs++;
750			}
751			desc->status = status & ~IRQ_AUTODETECT;
752			desc->handler->shutdown(i);
753		}
754		spin_unlock_irq(&desc->lock);
755	}
756
757	if (nr_irqs > 1)
758		irq_found = -irq_found;
759	return irq_found;
760}
761
762EXPORT_SYMBOL(probe_irq_off);
763
764#ifdef CONFIG_SMP
765void synchronize_irq(unsigned int irq)
766{
767        /* is there anything to synchronize with? */
768	if (!irq_desc[irq].action)
769		return;
770
771	while (irq_desc[irq].status & IRQ_INPROGRESS)
772		barrier();
773}
774#endif