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Linux/kernel/irq/manage.c

  1 /*
  2  * linux/kernel/irq/manage.c
  3  *
  4  * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
  5  * Copyright (C) 2005-2006 Thomas Gleixner
  6  *
  7  * This file contains driver APIs to the irq subsystem.
  8  */
  9 
 10 #define pr_fmt(fmt) "genirq: " fmt
 11 
 12 #include <linux/irq.h>
 13 #include <linux/kthread.h>
 14 #include <linux/module.h>
 15 #include <linux/random.h>
 16 #include <linux/interrupt.h>
 17 #include <linux/slab.h>
 18 #include <linux/sched.h>
 19 #include <linux/sched/rt.h>
 20 #include <linux/task_work.h>
 21 
 22 #include "internals.h"
 23 
 24 #ifdef CONFIG_IRQ_FORCED_THREADING
 25 __read_mostly bool force_irqthreads;
 26 
 27 static int __init setup_forced_irqthreads(char *arg)
 28 {
 29         force_irqthreads = true;
 30         return 0;
 31 }
 32 early_param("threadirqs", setup_forced_irqthreads);
 33 #endif
 34 
 35 static void __synchronize_hardirq(struct irq_desc *desc)
 36 {
 37         bool inprogress;
 38 
 39         do {
 40                 unsigned long flags;
 41 
 42                 /*
 43                  * Wait until we're out of the critical section.  This might
 44                  * give the wrong answer due to the lack of memory barriers.
 45                  */
 46                 while (irqd_irq_inprogress(&desc->irq_data))
 47                         cpu_relax();
 48 
 49                 /* Ok, that indicated we're done: double-check carefully. */
 50                 raw_spin_lock_irqsave(&desc->lock, flags);
 51                 inprogress = irqd_irq_inprogress(&desc->irq_data);
 52                 raw_spin_unlock_irqrestore(&desc->lock, flags);
 53 
 54                 /* Oops, that failed? */
 55         } while (inprogress);
 56 }
 57 
 58 /**
 59  *      synchronize_hardirq - wait for pending hard IRQ handlers (on other CPUs)
 60  *      @irq: interrupt number to wait for
 61  *
 62  *      This function waits for any pending hard IRQ handlers for this
 63  *      interrupt to complete before returning. If you use this
 64  *      function while holding a resource the IRQ handler may need you
 65  *      will deadlock. It does not take associated threaded handlers
 66  *      into account.
 67  *
 68  *      Do not use this for shutdown scenarios where you must be sure
 69  *      that all parts (hardirq and threaded handler) have completed.
 70  *
 71  *      Returns: false if a threaded handler is active.
 72  *
 73  *      This function may be called - with care - from IRQ context.
 74  */
 75 bool synchronize_hardirq(unsigned int irq)
 76 {
 77         struct irq_desc *desc = irq_to_desc(irq);
 78 
 79         if (desc) {
 80                 __synchronize_hardirq(desc);
 81                 return !atomic_read(&desc->threads_active);
 82         }
 83 
 84         return true;
 85 }
 86 EXPORT_SYMBOL(synchronize_hardirq);
 87 
 88 /**
 89  *      synchronize_irq - wait for pending IRQ handlers (on other CPUs)
 90  *      @irq: interrupt number to wait for
 91  *
 92  *      This function waits for any pending IRQ handlers for this interrupt
 93  *      to complete before returning. If you use this function while
 94  *      holding a resource the IRQ handler may need you will deadlock.
 95  *
 96  *      This function may be called - with care - from IRQ context.
 97  */
 98 void synchronize_irq(unsigned int irq)
 99 {
100         struct irq_desc *desc = irq_to_desc(irq);
101 
102         if (desc) {
103                 __synchronize_hardirq(desc);
104                 /*
105                  * We made sure that no hardirq handler is
106                  * running. Now verify that no threaded handlers are
107                  * active.
108                  */
109                 wait_event(desc->wait_for_threads,
110                            !atomic_read(&desc->threads_active));
111         }
112 }
113 EXPORT_SYMBOL(synchronize_irq);
114 
115 #ifdef CONFIG_SMP
116 cpumask_var_t irq_default_affinity;
117 
118 /**
119  *      irq_can_set_affinity - Check if the affinity of a given irq can be set
120  *      @irq:           Interrupt to check
121  *
122  */
123 int irq_can_set_affinity(unsigned int irq)
124 {
125         struct irq_desc *desc = irq_to_desc(irq);
126 
127         if (!desc || !irqd_can_balance(&desc->irq_data) ||
128             !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
129                 return 0;
130 
131         return 1;
132 }
133 
134 /**
135  *      irq_set_thread_affinity - Notify irq threads to adjust affinity
136  *      @desc:          irq descriptor which has affitnity changed
137  *
138  *      We just set IRQTF_AFFINITY and delegate the affinity setting
139  *      to the interrupt thread itself. We can not call
140  *      set_cpus_allowed_ptr() here as we hold desc->lock and this
141  *      code can be called from hard interrupt context.
142  */
143 void irq_set_thread_affinity(struct irq_desc *desc)
144 {
145         struct irqaction *action = desc->action;
146 
147         while (action) {
148                 if (action->thread)
149                         set_bit(IRQTF_AFFINITY, &action->thread_flags);
150                 action = action->next;
151         }
152 }
153 
154 #ifdef CONFIG_GENERIC_PENDING_IRQ
155 static inline bool irq_can_move_pcntxt(struct irq_data *data)
156 {
157         return irqd_can_move_in_process_context(data);
158 }
159 static inline bool irq_move_pending(struct irq_data *data)
160 {
161         return irqd_is_setaffinity_pending(data);
162 }
163 static inline void
164 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask)
165 {
166         cpumask_copy(desc->pending_mask, mask);
167 }
168 static inline void
169 irq_get_pending(struct cpumask *mask, struct irq_desc *desc)
170 {
171         cpumask_copy(mask, desc->pending_mask);
172 }
173 #else
174 static inline bool irq_can_move_pcntxt(struct irq_data *data) { return true; }
175 static inline bool irq_move_pending(struct irq_data *data) { return false; }
176 static inline void
177 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask) { }
178 static inline void
179 irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { }
180 #endif
181 
182 int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
183                         bool force)
184 {
185         struct irq_desc *desc = irq_data_to_desc(data);
186         struct irq_chip *chip = irq_data_get_irq_chip(data);
187         int ret;
188 
189         ret = chip->irq_set_affinity(data, mask, force);
190         switch (ret) {
191         case IRQ_SET_MASK_OK:
192         case IRQ_SET_MASK_OK_DONE:
193                 cpumask_copy(data->affinity, mask);
194         case IRQ_SET_MASK_OK_NOCOPY:
195                 irq_set_thread_affinity(desc);
196                 ret = 0;
197         }
198 
199         return ret;
200 }
201 
202 int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
203                             bool force)
204 {
205         struct irq_chip *chip = irq_data_get_irq_chip(data);
206         struct irq_desc *desc = irq_data_to_desc(data);
207         int ret = 0;
208 
209         if (!chip || !chip->irq_set_affinity)
210                 return -EINVAL;
211 
212         if (irq_can_move_pcntxt(data)) {
213                 ret = irq_do_set_affinity(data, mask, force);
214         } else {
215                 irqd_set_move_pending(data);
216                 irq_copy_pending(desc, mask);
217         }
218 
219         if (desc->affinity_notify) {
220                 kref_get(&desc->affinity_notify->kref);
221                 schedule_work(&desc->affinity_notify->work);
222         }
223         irqd_set(data, IRQD_AFFINITY_SET);
224 
225         return ret;
226 }
227 
228 int __irq_set_affinity(unsigned int irq, const struct cpumask *mask, bool force)
229 {
230         struct irq_desc *desc = irq_to_desc(irq);
231         unsigned long flags;
232         int ret;
233 
234         if (!desc)
235                 return -EINVAL;
236 
237         raw_spin_lock_irqsave(&desc->lock, flags);
238         ret = irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask, force);
239         raw_spin_unlock_irqrestore(&desc->lock, flags);
240         return ret;
241 }
242 
243 int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
244 {
245         unsigned long flags;
246         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
247 
248         if (!desc)
249                 return -EINVAL;
250         desc->affinity_hint = m;
251         irq_put_desc_unlock(desc, flags);
252         /* set the initial affinity to prevent every interrupt being on CPU0 */
253         if (m)
254                 __irq_set_affinity(irq, m, false);
255         return 0;
256 }
257 EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
258 
259 static void irq_affinity_notify(struct work_struct *work)
260 {
261         struct irq_affinity_notify *notify =
262                 container_of(work, struct irq_affinity_notify, work);
263         struct irq_desc *desc = irq_to_desc(notify->irq);
264         cpumask_var_t cpumask;
265         unsigned long flags;
266 
267         if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
268                 goto out;
269 
270         raw_spin_lock_irqsave(&desc->lock, flags);
271         if (irq_move_pending(&desc->irq_data))
272                 irq_get_pending(cpumask, desc);
273         else
274                 cpumask_copy(cpumask, desc->irq_data.affinity);
275         raw_spin_unlock_irqrestore(&desc->lock, flags);
276 
277         notify->notify(notify, cpumask);
278 
279         free_cpumask_var(cpumask);
280 out:
281         kref_put(&notify->kref, notify->release);
282 }
283 
284 /**
285  *      irq_set_affinity_notifier - control notification of IRQ affinity changes
286  *      @irq:           Interrupt for which to enable/disable notification
287  *      @notify:        Context for notification, or %NULL to disable
288  *                      notification.  Function pointers must be initialised;
289  *                      the other fields will be initialised by this function.
290  *
291  *      Must be called in process context.  Notification may only be enabled
292  *      after the IRQ is allocated and must be disabled before the IRQ is
293  *      freed using free_irq().
294  */
295 int
296 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
297 {
298         struct irq_desc *desc = irq_to_desc(irq);
299         struct irq_affinity_notify *old_notify;
300         unsigned long flags;
301 
302         /* The release function is promised process context */
303         might_sleep();
304 
305         if (!desc)
306                 return -EINVAL;
307 
308         /* Complete initialisation of *notify */
309         if (notify) {
310                 notify->irq = irq;
311                 kref_init(&notify->kref);
312                 INIT_WORK(&notify->work, irq_affinity_notify);
313         }
314 
315         raw_spin_lock_irqsave(&desc->lock, flags);
316         old_notify = desc->affinity_notify;
317         desc->affinity_notify = notify;
318         raw_spin_unlock_irqrestore(&desc->lock, flags);
319 
320         if (old_notify)
321                 kref_put(&old_notify->kref, old_notify->release);
322 
323         return 0;
324 }
325 EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
326 
327 #ifndef CONFIG_AUTO_IRQ_AFFINITY
328 /*
329  * Generic version of the affinity autoselector.
330  */
331 static int
332 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
333 {
334         struct cpumask *set = irq_default_affinity;
335         int node = desc->irq_data.node;
336 
337         /* Excludes PER_CPU and NO_BALANCE interrupts */
338         if (!irq_can_set_affinity(irq))
339                 return 0;
340 
341         /*
342          * Preserve an userspace affinity setup, but make sure that
343          * one of the targets is online.
344          */
345         if (irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
346                 if (cpumask_intersects(desc->irq_data.affinity,
347                                        cpu_online_mask))
348                         set = desc->irq_data.affinity;
349                 else
350                         irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
351         }
352 
353         cpumask_and(mask, cpu_online_mask, set);
354         if (node != NUMA_NO_NODE) {
355                 const struct cpumask *nodemask = cpumask_of_node(node);
356 
357                 /* make sure at least one of the cpus in nodemask is online */
358                 if (cpumask_intersects(mask, nodemask))
359                         cpumask_and(mask, mask, nodemask);
360         }
361         irq_do_set_affinity(&desc->irq_data, mask, false);
362         return 0;
363 }
364 #else
365 static inline int
366 setup_affinity(unsigned int irq, struct irq_desc *d, struct cpumask *mask)
367 {
368         return irq_select_affinity(irq);
369 }
370 #endif
371 
372 /*
373  * Called when affinity is set via /proc/irq
374  */
375 int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)
376 {
377         struct irq_desc *desc = irq_to_desc(irq);
378         unsigned long flags;
379         int ret;
380 
381         raw_spin_lock_irqsave(&desc->lock, flags);
382         ret = setup_affinity(irq, desc, mask);
383         raw_spin_unlock_irqrestore(&desc->lock, flags);
384         return ret;
385 }
386 
387 #else
388 static inline int
389 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
390 {
391         return 0;
392 }
393 #endif
394 
395 void __disable_irq(struct irq_desc *desc, unsigned int irq)
396 {
397         if (!desc->depth++)
398                 irq_disable(desc);
399 }
400 
401 static int __disable_irq_nosync(unsigned int irq)
402 {
403         unsigned long flags;
404         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
405 
406         if (!desc)
407                 return -EINVAL;
408         __disable_irq(desc, irq);
409         irq_put_desc_busunlock(desc, flags);
410         return 0;
411 }
412 
413 /**
414  *      disable_irq_nosync - disable an irq without waiting
415  *      @irq: Interrupt to disable
416  *
417  *      Disable the selected interrupt line.  Disables and Enables are
418  *      nested.
419  *      Unlike disable_irq(), this function does not ensure existing
420  *      instances of the IRQ handler have completed before returning.
421  *
422  *      This function may be called from IRQ context.
423  */
424 void disable_irq_nosync(unsigned int irq)
425 {
426         __disable_irq_nosync(irq);
427 }
428 EXPORT_SYMBOL(disable_irq_nosync);
429 
430 /**
431  *      disable_irq - disable an irq and wait for completion
432  *      @irq: Interrupt to disable
433  *
434  *      Disable the selected interrupt line.  Enables and Disables are
435  *      nested.
436  *      This function waits for any pending IRQ handlers for this interrupt
437  *      to complete before returning. If you use this function while
438  *      holding a resource the IRQ handler may need you will deadlock.
439  *
440  *      This function may be called - with care - from IRQ context.
441  */
442 void disable_irq(unsigned int irq)
443 {
444         if (!__disable_irq_nosync(irq))
445                 synchronize_irq(irq);
446 }
447 EXPORT_SYMBOL(disable_irq);
448 
449 /**
450  *      disable_hardirq - disables an irq and waits for hardirq completion
451  *      @irq: Interrupt to disable
452  *
453  *      Disable the selected interrupt line.  Enables and Disables are
454  *      nested.
455  *      This function waits for any pending hard IRQ handlers for this
456  *      interrupt to complete before returning. If you use this function while
457  *      holding a resource the hard IRQ handler may need you will deadlock.
458  *
459  *      When used to optimistically disable an interrupt from atomic context
460  *      the return value must be checked.
461  *
462  *      Returns: false if a threaded handler is active.
463  *
464  *      This function may be called - with care - from IRQ context.
465  */
466 bool disable_hardirq(unsigned int irq)
467 {
468         if (!__disable_irq_nosync(irq))
469                 return synchronize_hardirq(irq);
470 
471         return false;
472 }
473 EXPORT_SYMBOL_GPL(disable_hardirq);
474 
475 void __enable_irq(struct irq_desc *desc, unsigned int irq)
476 {
477         switch (desc->depth) {
478         case 0:
479  err_out:
480                 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
481                 break;
482         case 1: {
483                 if (desc->istate & IRQS_SUSPENDED)
484                         goto err_out;
485                 /* Prevent probing on this irq: */
486                 irq_settings_set_noprobe(desc);
487                 irq_enable(desc);
488                 check_irq_resend(desc, irq);
489                 /* fall-through */
490         }
491         default:
492                 desc->depth--;
493         }
494 }
495 
496 /**
497  *      enable_irq - enable handling of an irq
498  *      @irq: Interrupt to enable
499  *
500  *      Undoes the effect of one call to disable_irq().  If this
501  *      matches the last disable, processing of interrupts on this
502  *      IRQ line is re-enabled.
503  *
504  *      This function may be called from IRQ context only when
505  *      desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
506  */
507 void enable_irq(unsigned int irq)
508 {
509         unsigned long flags;
510         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
511 
512         if (!desc)
513                 return;
514         if (WARN(!desc->irq_data.chip,
515                  KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
516                 goto out;
517 
518         __enable_irq(desc, irq);
519 out:
520         irq_put_desc_busunlock(desc, flags);
521 }
522 EXPORT_SYMBOL(enable_irq);
523 
524 static int set_irq_wake_real(unsigned int irq, unsigned int on)
525 {
526         struct irq_desc *desc = irq_to_desc(irq);
527         int ret = -ENXIO;
528 
529         if (irq_desc_get_chip(desc)->flags &  IRQCHIP_SKIP_SET_WAKE)
530                 return 0;
531 
532         if (desc->irq_data.chip->irq_set_wake)
533                 ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
534 
535         return ret;
536 }
537 
538 /**
539  *      irq_set_irq_wake - control irq power management wakeup
540  *      @irq:   interrupt to control
541  *      @on:    enable/disable power management wakeup
542  *
543  *      Enable/disable power management wakeup mode, which is
544  *      disabled by default.  Enables and disables must match,
545  *      just as they match for non-wakeup mode support.
546  *
547  *      Wakeup mode lets this IRQ wake the system from sleep
548  *      states like "suspend to RAM".
549  */
550 int irq_set_irq_wake(unsigned int irq, unsigned int on)
551 {
552         unsigned long flags;
553         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
554         int ret = 0;
555 
556         if (!desc)
557                 return -EINVAL;
558 
559         /* wakeup-capable irqs can be shared between drivers that
560          * don't need to have the same sleep mode behaviors.
561          */
562         if (on) {
563                 if (desc->wake_depth++ == 0) {
564                         ret = set_irq_wake_real(irq, on);
565                         if (ret)
566                                 desc->wake_depth = 0;
567                         else
568                                 irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
569                 }
570         } else {
571                 if (desc->wake_depth == 0) {
572                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
573                 } else if (--desc->wake_depth == 0) {
574                         ret = set_irq_wake_real(irq, on);
575                         if (ret)
576                                 desc->wake_depth = 1;
577                         else
578                                 irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
579                 }
580         }
581         irq_put_desc_busunlock(desc, flags);
582         return ret;
583 }
584 EXPORT_SYMBOL(irq_set_irq_wake);
585 
586 /*
587  * Internal function that tells the architecture code whether a
588  * particular irq has been exclusively allocated or is available
589  * for driver use.
590  */
591 int can_request_irq(unsigned int irq, unsigned long irqflags)
592 {
593         unsigned long flags;
594         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
595         int canrequest = 0;
596 
597         if (!desc)
598                 return 0;
599 
600         if (irq_settings_can_request(desc)) {
601                 if (!desc->action ||
602                     irqflags & desc->action->flags & IRQF_SHARED)
603                         canrequest = 1;
604         }
605         irq_put_desc_unlock(desc, flags);
606         return canrequest;
607 }
608 
609 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
610                       unsigned long flags)
611 {
612         struct irq_chip *chip = desc->irq_data.chip;
613         int ret, unmask = 0;
614 
615         if (!chip || !chip->irq_set_type) {
616                 /*
617                  * IRQF_TRIGGER_* but the PIC does not support multiple
618                  * flow-types?
619                  */
620                 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
621                          chip ? (chip->name ? : "unknown") : "unknown");
622                 return 0;
623         }
624 
625         flags &= IRQ_TYPE_SENSE_MASK;
626 
627         if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
628                 if (!irqd_irq_masked(&desc->irq_data))
629                         mask_irq(desc);
630                 if (!irqd_irq_disabled(&desc->irq_data))
631                         unmask = 1;
632         }
633 
634         /* caller masked out all except trigger mode flags */
635         ret = chip->irq_set_type(&desc->irq_data, flags);
636 
637         switch (ret) {
638         case IRQ_SET_MASK_OK:
639         case IRQ_SET_MASK_OK_DONE:
640                 irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
641                 irqd_set(&desc->irq_data, flags);
642 
643         case IRQ_SET_MASK_OK_NOCOPY:
644                 flags = irqd_get_trigger_type(&desc->irq_data);
645                 irq_settings_set_trigger_mask(desc, flags);
646                 irqd_clear(&desc->irq_data, IRQD_LEVEL);
647                 irq_settings_clr_level(desc);
648                 if (flags & IRQ_TYPE_LEVEL_MASK) {
649                         irq_settings_set_level(desc);
650                         irqd_set(&desc->irq_data, IRQD_LEVEL);
651                 }
652 
653                 ret = 0;
654                 break;
655         default:
656                 pr_err("Setting trigger mode %lu for irq %u failed (%pF)\n",
657                        flags, irq, chip->irq_set_type);
658         }
659         if (unmask)
660                 unmask_irq(desc);
661         return ret;
662 }
663 
664 #ifdef CONFIG_HARDIRQS_SW_RESEND
665 int irq_set_parent(int irq, int parent_irq)
666 {
667         unsigned long flags;
668         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
669 
670         if (!desc)
671                 return -EINVAL;
672 
673         desc->parent_irq = parent_irq;
674 
675         irq_put_desc_unlock(desc, flags);
676         return 0;
677 }
678 #endif
679 
680 /*
681  * Default primary interrupt handler for threaded interrupts. Is
682  * assigned as primary handler when request_threaded_irq is called
683  * with handler == NULL. Useful for oneshot interrupts.
684  */
685 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
686 {
687         return IRQ_WAKE_THREAD;
688 }
689 
690 /*
691  * Primary handler for nested threaded interrupts. Should never be
692  * called.
693  */
694 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
695 {
696         WARN(1, "Primary handler called for nested irq %d\n", irq);
697         return IRQ_NONE;
698 }
699 
700 static int irq_wait_for_interrupt(struct irqaction *action)
701 {
702         set_current_state(TASK_INTERRUPTIBLE);
703 
704         while (!kthread_should_stop()) {
705 
706                 if (test_and_clear_bit(IRQTF_RUNTHREAD,
707                                        &action->thread_flags)) {
708                         __set_current_state(TASK_RUNNING);
709                         return 0;
710                 }
711                 schedule();
712                 set_current_state(TASK_INTERRUPTIBLE);
713         }
714         __set_current_state(TASK_RUNNING);
715         return -1;
716 }
717 
718 /*
719  * Oneshot interrupts keep the irq line masked until the threaded
720  * handler finished. unmask if the interrupt has not been disabled and
721  * is marked MASKED.
722  */
723 static void irq_finalize_oneshot(struct irq_desc *desc,
724                                  struct irqaction *action)
725 {
726         if (!(desc->istate & IRQS_ONESHOT))
727                 return;
728 again:
729         chip_bus_lock(desc);
730         raw_spin_lock_irq(&desc->lock);
731 
732         /*
733          * Implausible though it may be we need to protect us against
734          * the following scenario:
735          *
736          * The thread is faster done than the hard interrupt handler
737          * on the other CPU. If we unmask the irq line then the
738          * interrupt can come in again and masks the line, leaves due
739          * to IRQS_INPROGRESS and the irq line is masked forever.
740          *
741          * This also serializes the state of shared oneshot handlers
742          * versus "desc->threads_onehsot |= action->thread_mask;" in
743          * irq_wake_thread(). See the comment there which explains the
744          * serialization.
745          */
746         if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
747                 raw_spin_unlock_irq(&desc->lock);
748                 chip_bus_sync_unlock(desc);
749                 cpu_relax();
750                 goto again;
751         }
752 
753         /*
754          * Now check again, whether the thread should run. Otherwise
755          * we would clear the threads_oneshot bit of this thread which
756          * was just set.
757          */
758         if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
759                 goto out_unlock;
760 
761         desc->threads_oneshot &= ~action->thread_mask;
762 
763         if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
764             irqd_irq_masked(&desc->irq_data))
765                 unmask_threaded_irq(desc);
766 
767 out_unlock:
768         raw_spin_unlock_irq(&desc->lock);
769         chip_bus_sync_unlock(desc);
770 }
771 
772 #ifdef CONFIG_SMP
773 /*
774  * Check whether we need to change the affinity of the interrupt thread.
775  */
776 static void
777 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
778 {
779         cpumask_var_t mask;
780         bool valid = true;
781 
782         if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
783                 return;
784 
785         /*
786          * In case we are out of memory we set IRQTF_AFFINITY again and
787          * try again next time
788          */
789         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
790                 set_bit(IRQTF_AFFINITY, &action->thread_flags);
791                 return;
792         }
793 
794         raw_spin_lock_irq(&desc->lock);
795         /*
796          * This code is triggered unconditionally. Check the affinity
797          * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
798          */
799         if (desc->irq_data.affinity)
800                 cpumask_copy(mask, desc->irq_data.affinity);
801         else
802                 valid = false;
803         raw_spin_unlock_irq(&desc->lock);
804 
805         if (valid)
806                 set_cpus_allowed_ptr(current, mask);
807         free_cpumask_var(mask);
808 }
809 #else
810 static inline void
811 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
812 #endif
813 
814 /*
815  * Interrupts which are not explicitely requested as threaded
816  * interrupts rely on the implicit bh/preempt disable of the hard irq
817  * context. So we need to disable bh here to avoid deadlocks and other
818  * side effects.
819  */
820 static irqreturn_t
821 irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
822 {
823         irqreturn_t ret;
824 
825         local_bh_disable();
826         ret = action->thread_fn(action->irq, action->dev_id);
827         irq_finalize_oneshot(desc, action);
828         local_bh_enable();
829         return ret;
830 }
831 
832 /*
833  * Interrupts explicitly requested as threaded interrupts want to be
834  * preemtible - many of them need to sleep and wait for slow busses to
835  * complete.
836  */
837 static irqreturn_t irq_thread_fn(struct irq_desc *desc,
838                 struct irqaction *action)
839 {
840         irqreturn_t ret;
841 
842         ret = action->thread_fn(action->irq, action->dev_id);
843         irq_finalize_oneshot(desc, action);
844         return ret;
845 }
846 
847 static void wake_threads_waitq(struct irq_desc *desc)
848 {
849         if (atomic_dec_and_test(&desc->threads_active))
850                 wake_up(&desc->wait_for_threads);
851 }
852 
853 static void irq_thread_dtor(struct callback_head *unused)
854 {
855         struct task_struct *tsk = current;
856         struct irq_desc *desc;
857         struct irqaction *action;
858 
859         if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
860                 return;
861 
862         action = kthread_data(tsk);
863 
864         pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
865                tsk->comm, tsk->pid, action->irq);
866 
867 
868         desc = irq_to_desc(action->irq);
869         /*
870          * If IRQTF_RUNTHREAD is set, we need to decrement
871          * desc->threads_active and wake possible waiters.
872          */
873         if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
874                 wake_threads_waitq(desc);
875 
876         /* Prevent a stale desc->threads_oneshot */
877         irq_finalize_oneshot(desc, action);
878 }
879 
880 /*
881  * Interrupt handler thread
882  */
883 static int irq_thread(void *data)
884 {
885         struct callback_head on_exit_work;
886         struct irqaction *action = data;
887         struct irq_desc *desc = irq_to_desc(action->irq);
888         irqreturn_t (*handler_fn)(struct irq_desc *desc,
889                         struct irqaction *action);
890 
891         if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
892                                         &action->thread_flags))
893                 handler_fn = irq_forced_thread_fn;
894         else
895                 handler_fn = irq_thread_fn;
896 
897         init_task_work(&on_exit_work, irq_thread_dtor);
898         task_work_add(current, &on_exit_work, false);
899 
900         irq_thread_check_affinity(desc, action);
901 
902         while (!irq_wait_for_interrupt(action)) {
903                 irqreturn_t action_ret;
904 
905                 irq_thread_check_affinity(desc, action);
906 
907                 action_ret = handler_fn(desc, action);
908                 if (action_ret == IRQ_HANDLED)
909                         atomic_inc(&desc->threads_handled);
910 
911                 wake_threads_waitq(desc);
912         }
913 
914         /*
915          * This is the regular exit path. __free_irq() is stopping the
916          * thread via kthread_stop() after calling
917          * synchronize_irq(). So neither IRQTF_RUNTHREAD nor the
918          * oneshot mask bit can be set. We cannot verify that as we
919          * cannot touch the oneshot mask at this point anymore as
920          * __setup_irq() might have given out currents thread_mask
921          * again.
922          */
923         task_work_cancel(current, irq_thread_dtor);
924         return 0;
925 }
926 
927 /**
928  *      irq_wake_thread - wake the irq thread for the action identified by dev_id
929  *      @irq:           Interrupt line
930  *      @dev_id:        Device identity for which the thread should be woken
931  *
932  */
933 void irq_wake_thread(unsigned int irq, void *dev_id)
934 {
935         struct irq_desc *desc = irq_to_desc(irq);
936         struct irqaction *action;
937         unsigned long flags;
938 
939         if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
940                 return;
941 
942         raw_spin_lock_irqsave(&desc->lock, flags);
943         for (action = desc->action; action; action = action->next) {
944                 if (action->dev_id == dev_id) {
945                         if (action->thread)
946                                 __irq_wake_thread(desc, action);
947                         break;
948                 }
949         }
950         raw_spin_unlock_irqrestore(&desc->lock, flags);
951 }
952 EXPORT_SYMBOL_GPL(irq_wake_thread);
953 
954 static void irq_setup_forced_threading(struct irqaction *new)
955 {
956         if (!force_irqthreads)
957                 return;
958         if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
959                 return;
960 
961         new->flags |= IRQF_ONESHOT;
962 
963         if (!new->thread_fn) {
964                 set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
965                 new->thread_fn = new->handler;
966                 new->handler = irq_default_primary_handler;
967         }
968 }
969 
970 static int irq_request_resources(struct irq_desc *desc)
971 {
972         struct irq_data *d = &desc->irq_data;
973         struct irq_chip *c = d->chip;
974 
975         return c->irq_request_resources ? c->irq_request_resources(d) : 0;
976 }
977 
978 static void irq_release_resources(struct irq_desc *desc)
979 {
980         struct irq_data *d = &desc->irq_data;
981         struct irq_chip *c = d->chip;
982 
983         if (c->irq_release_resources)
984                 c->irq_release_resources(d);
985 }
986 
987 /*
988  * Internal function to register an irqaction - typically used to
989  * allocate special interrupts that are part of the architecture.
990  */
991 static int
992 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
993 {
994         struct irqaction *old, **old_ptr;
995         unsigned long flags, thread_mask = 0;
996         int ret, nested, shared = 0;
997         cpumask_var_t mask;
998 
999         if (!desc)
1000                 return -EINVAL;
1001 
1002         if (desc->irq_data.chip == &no_irq_chip)
1003                 return -ENOSYS;
1004         if (!try_module_get(desc->owner))
1005                 return -ENODEV;
1006 
1007         /*
1008          * Check whether the interrupt nests into another interrupt
1009          * thread.
1010          */
1011         nested = irq_settings_is_nested_thread(desc);
1012         if (nested) {
1013                 if (!new->thread_fn) {
1014                         ret = -EINVAL;
1015                         goto out_mput;
1016                 }
1017                 /*
1018                  * Replace the primary handler which was provided from
1019                  * the driver for non nested interrupt handling by the
1020                  * dummy function which warns when called.
1021                  */
1022                 new->handler = irq_nested_primary_handler;
1023         } else {
1024                 if (irq_settings_can_thread(desc))
1025                         irq_setup_forced_threading(new);
1026         }
1027 
1028         /*
1029          * Create a handler thread when a thread function is supplied
1030          * and the interrupt does not nest into another interrupt
1031          * thread.
1032          */
1033         if (new->thread_fn && !nested) {
1034                 struct task_struct *t;
1035                 static const struct sched_param param = {
1036                         .sched_priority = MAX_USER_RT_PRIO/2,
1037                 };
1038 
1039                 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
1040                                    new->name);
1041                 if (IS_ERR(t)) {
1042                         ret = PTR_ERR(t);
1043                         goto out_mput;
1044                 }
1045 
1046                 sched_setscheduler_nocheck(t, SCHED_FIFO, &param);
1047 
1048                 /*
1049                  * We keep the reference to the task struct even if
1050                  * the thread dies to avoid that the interrupt code
1051                  * references an already freed task_struct.
1052                  */
1053                 get_task_struct(t);
1054                 new->thread = t;
1055                 /*
1056                  * Tell the thread to set its affinity. This is
1057                  * important for shared interrupt handlers as we do
1058                  * not invoke setup_affinity() for the secondary
1059                  * handlers as everything is already set up. Even for
1060                  * interrupts marked with IRQF_NO_BALANCE this is
1061                  * correct as we want the thread to move to the cpu(s)
1062                  * on which the requesting code placed the interrupt.
1063                  */
1064                 set_bit(IRQTF_AFFINITY, &new->thread_flags);
1065         }
1066 
1067         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
1068                 ret = -ENOMEM;
1069                 goto out_thread;
1070         }
1071 
1072         /*
1073          * Drivers are often written to work w/o knowledge about the
1074          * underlying irq chip implementation, so a request for a
1075          * threaded irq without a primary hard irq context handler
1076          * requires the ONESHOT flag to be set. Some irq chips like
1077          * MSI based interrupts are per se one shot safe. Check the
1078          * chip flags, so we can avoid the unmask dance at the end of
1079          * the threaded handler for those.
1080          */
1081         if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
1082                 new->flags &= ~IRQF_ONESHOT;
1083 
1084         /*
1085          * The following block of code has to be executed atomically
1086          */
1087         raw_spin_lock_irqsave(&desc->lock, flags);
1088         old_ptr = &desc->action;
1089         old = *old_ptr;
1090         if (old) {
1091                 /*
1092                  * Can't share interrupts unless both agree to and are
1093                  * the same type (level, edge, polarity). So both flag
1094                  * fields must have IRQF_SHARED set and the bits which
1095                  * set the trigger type must match. Also all must
1096                  * agree on ONESHOT.
1097                  */
1098                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
1099                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
1100                     ((old->flags ^ new->flags) & IRQF_ONESHOT))
1101                         goto mismatch;
1102 
1103                 /* All handlers must agree on per-cpuness */
1104                 if ((old->flags & IRQF_PERCPU) !=
1105                     (new->flags & IRQF_PERCPU))
1106                         goto mismatch;
1107 
1108                 /* add new interrupt at end of irq queue */
1109                 do {
1110                         /*
1111                          * Or all existing action->thread_mask bits,
1112                          * so we can find the next zero bit for this
1113                          * new action.
1114                          */
1115                         thread_mask |= old->thread_mask;
1116                         old_ptr = &old->next;
1117                         old = *old_ptr;
1118                 } while (old);
1119                 shared = 1;
1120         }
1121 
1122         /*
1123          * Setup the thread mask for this irqaction for ONESHOT. For
1124          * !ONESHOT irqs the thread mask is 0 so we can avoid a
1125          * conditional in irq_wake_thread().
1126          */
1127         if (new->flags & IRQF_ONESHOT) {
1128                 /*
1129                  * Unlikely to have 32 resp 64 irqs sharing one line,
1130                  * but who knows.
1131                  */
1132                 if (thread_mask == ~0UL) {
1133                         ret = -EBUSY;
1134                         goto out_mask;
1135                 }
1136                 /*
1137                  * The thread_mask for the action is or'ed to
1138                  * desc->thread_active to indicate that the
1139                  * IRQF_ONESHOT thread handler has been woken, but not
1140                  * yet finished. The bit is cleared when a thread
1141                  * completes. When all threads of a shared interrupt
1142                  * line have completed desc->threads_active becomes
1143                  * zero and the interrupt line is unmasked. See
1144                  * handle.c:irq_wake_thread() for further information.
1145                  *
1146                  * If no thread is woken by primary (hard irq context)
1147                  * interrupt handlers, then desc->threads_active is
1148                  * also checked for zero to unmask the irq line in the
1149                  * affected hard irq flow handlers
1150                  * (handle_[fasteoi|level]_irq).
1151                  *
1152                  * The new action gets the first zero bit of
1153                  * thread_mask assigned. See the loop above which or's
1154                  * all existing action->thread_mask bits.
1155                  */
1156                 new->thread_mask = 1 << ffz(thread_mask);
1157 
1158         } else if (new->handler == irq_default_primary_handler &&
1159                    !(desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)) {
1160                 /*
1161                  * The interrupt was requested with handler = NULL, so
1162                  * we use the default primary handler for it. But it
1163                  * does not have the oneshot flag set. In combination
1164                  * with level interrupts this is deadly, because the
1165                  * default primary handler just wakes the thread, then
1166                  * the irq lines is reenabled, but the device still
1167                  * has the level irq asserted. Rinse and repeat....
1168                  *
1169                  * While this works for edge type interrupts, we play
1170                  * it safe and reject unconditionally because we can't
1171                  * say for sure which type this interrupt really
1172                  * has. The type flags are unreliable as the
1173                  * underlying chip implementation can override them.
1174                  */
1175                 pr_err("Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
1176                        irq);
1177                 ret = -EINVAL;
1178                 goto out_mask;
1179         }
1180 
1181         if (!shared) {
1182                 ret = irq_request_resources(desc);
1183                 if (ret) {
1184                         pr_err("Failed to request resources for %s (irq %d) on irqchip %s\n",
1185                                new->name, irq, desc->irq_data.chip->name);
1186                         goto out_mask;
1187                 }
1188 
1189                 init_waitqueue_head(&desc->wait_for_threads);
1190 
1191                 /* Setup the type (level, edge polarity) if configured: */
1192                 if (new->flags & IRQF_TRIGGER_MASK) {
1193                         ret = __irq_set_trigger(desc, irq,
1194                                         new->flags & IRQF_TRIGGER_MASK);
1195 
1196                         if (ret)
1197                                 goto out_mask;
1198                 }
1199 
1200                 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1201                                   IRQS_ONESHOT | IRQS_WAITING);
1202                 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1203 
1204                 if (new->flags & IRQF_PERCPU) {
1205                         irqd_set(&desc->irq_data, IRQD_PER_CPU);
1206                         irq_settings_set_per_cpu(desc);
1207                 }
1208 
1209                 if (new->flags & IRQF_ONESHOT)
1210                         desc->istate |= IRQS_ONESHOT;
1211 
1212                 if (irq_settings_can_autoenable(desc))
1213                         irq_startup(desc, true);
1214                 else
1215                         /* Undo nested disables: */
1216                         desc->depth = 1;
1217 
1218                 /* Exclude IRQ from balancing if requested */
1219                 if (new->flags & IRQF_NOBALANCING) {
1220                         irq_settings_set_no_balancing(desc);
1221                         irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1222                 }
1223 
1224                 /* Set default affinity mask once everything is setup */
1225                 setup_affinity(irq, desc, mask);
1226 
1227         } else if (new->flags & IRQF_TRIGGER_MASK) {
1228                 unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1229                 unsigned int omsk = irq_settings_get_trigger_mask(desc);
1230 
1231                 if (nmsk != omsk)
1232                         /* hope the handler works with current  trigger mode */
1233                         pr_warning("irq %d uses trigger mode %u; requested %u\n",
1234                                    irq, nmsk, omsk);
1235         }
1236 
1237         new->irq = irq;
1238         *old_ptr = new;
1239 
1240         irq_pm_install_action(desc, new);
1241 
1242         /* Reset broken irq detection when installing new handler */
1243         desc->irq_count = 0;
1244         desc->irqs_unhandled = 0;
1245 
1246         /*
1247          * Check whether we disabled the irq via the spurious handler
1248          * before. Reenable it and give it another chance.
1249          */
1250         if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1251                 desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1252                 __enable_irq(desc, irq);
1253         }
1254 
1255         raw_spin_unlock_irqrestore(&desc->lock, flags);
1256 
1257         /*
1258          * Strictly no need to wake it up, but hung_task complains
1259          * when no hard interrupt wakes the thread up.
1260          */
1261         if (new->thread)
1262                 wake_up_process(new->thread);
1263 
1264         register_irq_proc(irq, desc);
1265         new->dir = NULL;
1266         register_handler_proc(irq, new);
1267         free_cpumask_var(mask);
1268 
1269         return 0;
1270 
1271 mismatch:
1272         if (!(new->flags & IRQF_PROBE_SHARED)) {
1273                 pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
1274                        irq, new->flags, new->name, old->flags, old->name);
1275 #ifdef CONFIG_DEBUG_SHIRQ
1276                 dump_stack();
1277 #endif
1278         }
1279         ret = -EBUSY;
1280 
1281 out_mask:
1282         raw_spin_unlock_irqrestore(&desc->lock, flags);
1283         free_cpumask_var(mask);
1284 
1285 out_thread:
1286         if (new->thread) {
1287                 struct task_struct *t = new->thread;
1288 
1289                 new->thread = NULL;
1290                 kthread_stop(t);
1291                 put_task_struct(t);
1292         }
1293 out_mput:
1294         module_put(desc->owner);
1295         return ret;
1296 }
1297 
1298 /**
1299  *      setup_irq - setup an interrupt
1300  *      @irq: Interrupt line to setup
1301  *      @act: irqaction for the interrupt
1302  *
1303  * Used to statically setup interrupts in the early boot process.
1304  */
1305 int setup_irq(unsigned int irq, struct irqaction *act)
1306 {
1307         int retval;
1308         struct irq_desc *desc = irq_to_desc(irq);
1309 
1310         if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1311                 return -EINVAL;
1312         chip_bus_lock(desc);
1313         retval = __setup_irq(irq, desc, act);
1314         chip_bus_sync_unlock(desc);
1315 
1316         return retval;
1317 }
1318 EXPORT_SYMBOL_GPL(setup_irq);
1319 
1320 /*
1321  * Internal function to unregister an irqaction - used to free
1322  * regular and special interrupts that are part of the architecture.
1323  */
1324 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
1325 {
1326         struct irq_desc *desc = irq_to_desc(irq);
1327         struct irqaction *action, **action_ptr;
1328         unsigned long flags;
1329 
1330         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1331 
1332         if (!desc)
1333                 return NULL;
1334 
1335         raw_spin_lock_irqsave(&desc->lock, flags);
1336 
1337         /*
1338          * There can be multiple actions per IRQ descriptor, find the right
1339          * one based on the dev_id:
1340          */
1341         action_ptr = &desc->action;
1342         for (;;) {
1343                 action = *action_ptr;
1344 
1345                 if (!action) {
1346                         WARN(1, "Trying to free already-free IRQ %d\n", irq);
1347                         raw_spin_unlock_irqrestore(&desc->lock, flags);
1348 
1349                         return NULL;
1350                 }
1351 
1352                 if (action->dev_id == dev_id)
1353                         break;
1354                 action_ptr = &action->next;
1355         }
1356 
1357         /* Found it - now remove it from the list of entries: */
1358         *action_ptr = action->next;
1359 
1360         irq_pm_remove_action(desc, action);
1361 
1362         /* If this was the last handler, shut down the IRQ line: */
1363         if (!desc->action) {
1364                 irq_shutdown(desc);
1365                 irq_release_resources(desc);
1366         }
1367 
1368 #ifdef CONFIG_SMP
1369         /* make sure affinity_hint is cleaned up */
1370         if (WARN_ON_ONCE(desc->affinity_hint))
1371                 desc->affinity_hint = NULL;
1372 #endif
1373 
1374         raw_spin_unlock_irqrestore(&desc->lock, flags);
1375 
1376         unregister_handler_proc(irq, action);
1377 
1378         /* Make sure it's not being used on another CPU: */
1379         synchronize_irq(irq);
1380 
1381 #ifdef CONFIG_DEBUG_SHIRQ
1382         /*
1383          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1384          * event to happen even now it's being freed, so let's make sure that
1385          * is so by doing an extra call to the handler ....
1386          *
1387          * ( We do this after actually deregistering it, to make sure that a
1388          *   'real' IRQ doesn't run in * parallel with our fake. )
1389          */
1390         if (action->flags & IRQF_SHARED) {
1391                 local_irq_save(flags);
1392                 action->handler(irq, dev_id);
1393                 local_irq_restore(flags);
1394         }
1395 #endif
1396 
1397         if (action->thread) {
1398                 kthread_stop(action->thread);
1399                 put_task_struct(action->thread);
1400         }
1401 
1402         module_put(desc->owner);
1403         return action;
1404 }
1405 
1406 /**
1407  *      remove_irq - free an interrupt
1408  *      @irq: Interrupt line to free
1409  *      @act: irqaction for the interrupt
1410  *
1411  * Used to remove interrupts statically setup by the early boot process.
1412  */
1413 void remove_irq(unsigned int irq, struct irqaction *act)
1414 {
1415         struct irq_desc *desc = irq_to_desc(irq);
1416 
1417         if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1418             __free_irq(irq, act->dev_id);
1419 }
1420 EXPORT_SYMBOL_GPL(remove_irq);
1421 
1422 /**
1423  *      free_irq - free an interrupt allocated with request_irq
1424  *      @irq: Interrupt line to free
1425  *      @dev_id: Device identity to free
1426  *
1427  *      Remove an interrupt handler. The handler is removed and if the
1428  *      interrupt line is no longer in use by any driver it is disabled.
1429  *      On a shared IRQ the caller must ensure the interrupt is disabled
1430  *      on the card it drives before calling this function. The function
1431  *      does not return until any executing interrupts for this IRQ
1432  *      have completed.
1433  *
1434  *      This function must not be called from interrupt context.
1435  */
1436 void free_irq(unsigned int irq, void *dev_id)
1437 {
1438         struct irq_desc *desc = irq_to_desc(irq);
1439 
1440         if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1441                 return;
1442 
1443 #ifdef CONFIG_SMP
1444         if (WARN_ON(desc->affinity_notify))
1445                 desc->affinity_notify = NULL;
1446 #endif
1447 
1448         chip_bus_lock(desc);
1449         kfree(__free_irq(irq, dev_id));
1450         chip_bus_sync_unlock(desc);
1451 }
1452 EXPORT_SYMBOL(free_irq);
1453 
1454 /**
1455  *      request_threaded_irq - allocate an interrupt line
1456  *      @irq: Interrupt line to allocate
1457  *      @handler: Function to be called when the IRQ occurs.
1458  *                Primary handler for threaded interrupts
1459  *                If NULL and thread_fn != NULL the default
1460  *                primary handler is installed
1461  *      @thread_fn: Function called from the irq handler thread
1462  *                  If NULL, no irq thread is created
1463  *      @irqflags: Interrupt type flags
1464  *      @devname: An ascii name for the claiming device
1465  *      @dev_id: A cookie passed back to the handler function
1466  *
1467  *      This call allocates interrupt resources and enables the
1468  *      interrupt line and IRQ handling. From the point this
1469  *      call is made your handler function may be invoked. Since
1470  *      your handler function must clear any interrupt the board
1471  *      raises, you must take care both to initialise your hardware
1472  *      and to set up the interrupt handler in the right order.
1473  *
1474  *      If you want to set up a threaded irq handler for your device
1475  *      then you need to supply @handler and @thread_fn. @handler is
1476  *      still called in hard interrupt context and has to check
1477  *      whether the interrupt originates from the device. If yes it
1478  *      needs to disable the interrupt on the device and return
1479  *      IRQ_WAKE_THREAD which will wake up the handler thread and run
1480  *      @thread_fn. This split handler design is necessary to support
1481  *      shared interrupts.
1482  *
1483  *      Dev_id must be globally unique. Normally the address of the
1484  *      device data structure is used as the cookie. Since the handler
1485  *      receives this value it makes sense to use it.
1486  *
1487  *      If your interrupt is shared you must pass a non NULL dev_id
1488  *      as this is required when freeing the interrupt.
1489  *
1490  *      Flags:
1491  *
1492  *      IRQF_SHARED             Interrupt is shared
1493  *      IRQF_TRIGGER_*          Specify active edge(s) or level
1494  *
1495  */
1496 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1497                          irq_handler_t thread_fn, unsigned long irqflags,
1498                          const char *devname, void *dev_id)
1499 {
1500         struct irqaction *action;
1501         struct irq_desc *desc;
1502         int retval;
1503 
1504         /*
1505          * Sanity-check: shared interrupts must pass in a real dev-ID,
1506          * otherwise we'll have trouble later trying to figure out
1507          * which interrupt is which (messes up the interrupt freeing
1508          * logic etc).
1509          *
1510          * Also IRQF_COND_SUSPEND only makes sense for shared interrupts and
1511          * it cannot be set along with IRQF_NO_SUSPEND.
1512          */
1513         if (((irqflags & IRQF_SHARED) && !dev_id) ||
1514             (!(irqflags & IRQF_SHARED) && (irqflags & IRQF_COND_SUSPEND)) ||
1515             ((irqflags & IRQF_NO_SUSPEND) && (irqflags & IRQF_COND_SUSPEND)))
1516                 return -EINVAL;
1517 
1518         desc = irq_to_desc(irq);
1519         if (!desc)
1520                 return -EINVAL;
1521 
1522         if (!irq_settings_can_request(desc) ||
1523             WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1524                 return -EINVAL;
1525 
1526         if (!handler) {
1527                 if (!thread_fn)
1528                         return -EINVAL;
1529                 handler = irq_default_primary_handler;
1530         }
1531 
1532         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1533         if (!action)
1534                 return -ENOMEM;
1535 
1536         action->handler = handler;
1537         action->thread_fn = thread_fn;
1538         action->flags = irqflags;
1539         action->name = devname;
1540         action->dev_id = dev_id;
1541 
1542         chip_bus_lock(desc);
1543         retval = __setup_irq(irq, desc, action);
1544         chip_bus_sync_unlock(desc);
1545 
1546         if (retval)
1547                 kfree(action);
1548 
1549 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
1550         if (!retval && (irqflags & IRQF_SHARED)) {
1551                 /*
1552                  * It's a shared IRQ -- the driver ought to be prepared for it
1553                  * to happen immediately, so let's make sure....
1554                  * We disable the irq to make sure that a 'real' IRQ doesn't
1555                  * run in parallel with our fake.
1556                  */
1557                 unsigned long flags;
1558 
1559                 disable_irq(irq);
1560                 local_irq_save(flags);
1561 
1562                 handler(irq, dev_id);
1563 
1564                 local_irq_restore(flags);
1565                 enable_irq(irq);
1566         }
1567 #endif
1568         return retval;
1569 }
1570 EXPORT_SYMBOL(request_threaded_irq);
1571 
1572 /**
1573  *      request_any_context_irq - allocate an interrupt line
1574  *      @irq: Interrupt line to allocate
1575  *      @handler: Function to be called when the IRQ occurs.
1576  *                Threaded handler for threaded interrupts.
1577  *      @flags: Interrupt type flags
1578  *      @name: An ascii name for the claiming device
1579  *      @dev_id: A cookie passed back to the handler function
1580  *
1581  *      This call allocates interrupt resources and enables the
1582  *      interrupt line and IRQ handling. It selects either a
1583  *      hardirq or threaded handling method depending on the
1584  *      context.
1585  *
1586  *      On failure, it returns a negative value. On success,
1587  *      it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1588  */
1589 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1590                             unsigned long flags, const char *name, void *dev_id)
1591 {
1592         struct irq_desc *desc = irq_to_desc(irq);
1593         int ret;
1594 
1595         if (!desc)
1596                 return -EINVAL;
1597 
1598         if (irq_settings_is_nested_thread(desc)) {
1599                 ret = request_threaded_irq(irq, NULL, handler,
1600                                            flags, name, dev_id);
1601                 return !ret ? IRQC_IS_NESTED : ret;
1602         }
1603 
1604         ret = request_irq(irq, handler, flags, name, dev_id);
1605         return !ret ? IRQC_IS_HARDIRQ : ret;
1606 }
1607 EXPORT_SYMBOL_GPL(request_any_context_irq);
1608 
1609 void enable_percpu_irq(unsigned int irq, unsigned int type)
1610 {
1611         unsigned int cpu = smp_processor_id();
1612         unsigned long flags;
1613         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1614 
1615         if (!desc)
1616                 return;
1617 
1618         type &= IRQ_TYPE_SENSE_MASK;
1619         if (type != IRQ_TYPE_NONE) {
1620                 int ret;
1621 
1622                 ret = __irq_set_trigger(desc, irq, type);
1623 
1624                 if (ret) {
1625                         WARN(1, "failed to set type for IRQ%d\n", irq);
1626                         goto out;
1627                 }
1628         }
1629 
1630         irq_percpu_enable(desc, cpu);
1631 out:
1632         irq_put_desc_unlock(desc, flags);
1633 }
1634 EXPORT_SYMBOL_GPL(enable_percpu_irq);
1635 
1636 void disable_percpu_irq(unsigned int irq)
1637 {
1638         unsigned int cpu = smp_processor_id();
1639         unsigned long flags;
1640         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1641 
1642         if (!desc)
1643                 return;
1644 
1645         irq_percpu_disable(desc, cpu);
1646         irq_put_desc_unlock(desc, flags);
1647 }
1648 EXPORT_SYMBOL_GPL(disable_percpu_irq);
1649 
1650 /*
1651  * Internal function to unregister a percpu irqaction.
1652  */
1653 static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1654 {
1655         struct irq_desc *desc = irq_to_desc(irq);
1656         struct irqaction *action;
1657         unsigned long flags;
1658 
1659         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1660 
1661         if (!desc)
1662                 return NULL;
1663 
1664         raw_spin_lock_irqsave(&desc->lock, flags);
1665 
1666         action = desc->action;
1667         if (!action || action->percpu_dev_id != dev_id) {
1668                 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1669                 goto bad;
1670         }
1671 
1672         if (!cpumask_empty(desc->percpu_enabled)) {
1673                 WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
1674                      irq, cpumask_first(desc->percpu_enabled));
1675                 goto bad;
1676         }
1677 
1678         /* Found it - now remove it from the list of entries: */
1679         desc->action = NULL;
1680 
1681         raw_spin_unlock_irqrestore(&desc->lock, flags);
1682 
1683         unregister_handler_proc(irq, action);
1684 
1685         module_put(desc->owner);
1686         return action;
1687 
1688 bad:
1689         raw_spin_unlock_irqrestore(&desc->lock, flags);
1690         return NULL;
1691 }
1692 
1693 /**
1694  *      remove_percpu_irq - free a per-cpu interrupt
1695  *      @irq: Interrupt line to free
1696  *      @act: irqaction for the interrupt
1697  *
1698  * Used to remove interrupts statically setup by the early boot process.
1699  */
1700 void remove_percpu_irq(unsigned int irq, struct irqaction *act)
1701 {
1702         struct irq_desc *desc = irq_to_desc(irq);
1703 
1704         if (desc && irq_settings_is_per_cpu_devid(desc))
1705             __free_percpu_irq(irq, act->percpu_dev_id);
1706 }
1707 
1708 /**
1709  *      free_percpu_irq - free an interrupt allocated with request_percpu_irq
1710  *      @irq: Interrupt line to free
1711  *      @dev_id: Device identity to free
1712  *
1713  *      Remove a percpu interrupt handler. The handler is removed, but
1714  *      the interrupt line is not disabled. This must be done on each
1715  *      CPU before calling this function. The function does not return
1716  *      until any executing interrupts for this IRQ have completed.
1717  *
1718  *      This function must not be called from interrupt context.
1719  */
1720 void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1721 {
1722         struct irq_desc *desc = irq_to_desc(irq);
1723 
1724         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1725                 return;
1726 
1727         chip_bus_lock(desc);
1728         kfree(__free_percpu_irq(irq, dev_id));
1729         chip_bus_sync_unlock(desc);
1730 }
1731 
1732 /**
1733  *      setup_percpu_irq - setup a per-cpu interrupt
1734  *      @irq: Interrupt line to setup
1735  *      @act: irqaction for the interrupt
1736  *
1737  * Used to statically setup per-cpu interrupts in the early boot process.
1738  */
1739 int setup_percpu_irq(unsigned int irq, struct irqaction *act)
1740 {
1741         struct irq_desc *desc = irq_to_desc(irq);
1742         int retval;
1743 
1744         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1745                 return -EINVAL;
1746         chip_bus_lock(desc);
1747         retval = __setup_irq(irq, desc, act);
1748         chip_bus_sync_unlock(desc);
1749 
1750         return retval;
1751 }
1752 
1753 /**
1754  *      request_percpu_irq - allocate a percpu interrupt line
1755  *      @irq: Interrupt line to allocate
1756  *      @handler: Function to be called when the IRQ occurs.
1757  *      @devname: An ascii name for the claiming device
1758  *      @dev_id: A percpu cookie passed back to the handler function
1759  *
1760  *      This call allocates interrupt resources, but doesn't
1761  *      automatically enable the interrupt. It has to be done on each
1762  *      CPU using enable_percpu_irq().
1763  *
1764  *      Dev_id must be globally unique. It is a per-cpu variable, and
1765  *      the handler gets called with the interrupted CPU's instance of
1766  *      that variable.
1767  */
1768 int request_percpu_irq(unsigned int irq, irq_handler_t handler,
1769                        const char *devname, void __percpu *dev_id)
1770 {
1771         struct irqaction *action;
1772         struct irq_desc *desc;
1773         int retval;
1774 
1775         if (!dev_id)
1776                 return -EINVAL;
1777 
1778         desc = irq_to_desc(irq);
1779         if (!desc || !irq_settings_can_request(desc) ||
1780             !irq_settings_is_per_cpu_devid(desc))
1781                 return -EINVAL;
1782 
1783         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1784         if (!action)
1785                 return -ENOMEM;
1786 
1787         action->handler = handler;
1788         action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
1789         action->name = devname;
1790         action->percpu_dev_id = dev_id;
1791 
1792         chip_bus_lock(desc);
1793         retval = __setup_irq(irq, desc, action);
1794         chip_bus_sync_unlock(desc);
1795 
1796         if (retval)
1797                 kfree(action);
1798 
1799         return retval;
1800 }
1801 
1802 /**
1803  *      irq_get_irqchip_state - returns the irqchip state of a interrupt.
1804  *      @irq: Interrupt line that is forwarded to a VM
1805  *      @which: One of IRQCHIP_STATE_* the caller wants to know about
1806  *      @state: a pointer to a boolean where the state is to be storeed
1807  *
1808  *      This call snapshots the internal irqchip state of an
1809  *      interrupt, returning into @state the bit corresponding to
1810  *      stage @which
1811  *
1812  *      This function should be called with preemption disabled if the
1813  *      interrupt controller has per-cpu registers.
1814  */
1815 int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
1816                           bool *state)
1817 {
1818         struct irq_desc *desc;
1819         struct irq_data *data;
1820         struct irq_chip *chip;
1821         unsigned long flags;
1822         int err = -EINVAL;
1823 
1824         desc = irq_get_desc_buslock(irq, &flags, 0);
1825         if (!desc)
1826                 return err;
1827 
1828         data = irq_desc_get_irq_data(desc);
1829 
1830         do {
1831                 chip = irq_data_get_irq_chip(data);
1832                 if (chip->irq_get_irqchip_state)
1833                         break;
1834 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
1835                 data = data->parent_data;
1836 #else
1837                 data = NULL;
1838 #endif
1839         } while (data);
1840 
1841         if (data)
1842                 err = chip->irq_get_irqchip_state(data, which, state);
1843 
1844         irq_put_desc_busunlock(desc, flags);
1845         return err;
1846 }
1847 
1848 /**
1849  *      irq_set_irqchip_state - set the state of a forwarded interrupt.
1850  *      @irq: Interrupt line that is forwarded to a VM
1851  *      @which: State to be restored (one of IRQCHIP_STATE_*)
1852  *      @val: Value corresponding to @which
1853  *
1854  *      This call sets the internal irqchip state of an interrupt,
1855  *      depending on the value of @which.
1856  *
1857  *      This function should be called with preemption disabled if the
1858  *      interrupt controller has per-cpu registers.
1859  */
1860 int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
1861                           bool val)
1862 {
1863         struct irq_desc *desc;
1864         struct irq_data *data;
1865         struct irq_chip *chip;
1866         unsigned long flags;
1867         int err = -EINVAL;
1868 
1869         desc = irq_get_desc_buslock(irq, &flags, 0);
1870         if (!desc)
1871                 return err;
1872 
1873         data = irq_desc_get_irq_data(desc);
1874 
1875         do {
1876                 chip = irq_data_get_irq_chip(data);
1877                 if (chip->irq_set_irqchip_state)
1878                         break;
1879 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
1880                 data = data->parent_data;
1881 #else
1882                 data = NULL;
1883 #endif
1884         } while (data);
1885 
1886         if (data)
1887                 err = chip->irq_set_irqchip_state(data, which, val);
1888 
1889         irq_put_desc_busunlock(desc, flags);
1890         return err;
1891 }
1892 

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