sys/dev/drm/include/linux/interrupt.h

   1 /*
   2  * Copyright (c) 2017 François Tigeot
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice unmodified, this list of conditions, and the following
  10  *    disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #ifndef _LINUX_INTERRUPT_H_
  28 #define _LINUX_INTERRUPT_H_
  29
  30 #include <linux/kernel.h>
  31 #include <linux/bitops.h>
  32 #include <linux/irqflags.h>
  33 #include <linux/kref.h>
  34
  35 #include <linux/atomic.h>
  36
  37 struct tasklet_struct {
  38         unsigned long state;
  39         void (*func)(unsigned long);
  40         unsigned long data;
  41         struct lock lock;
  42 };
  43
  44 enum {
  45         TASKLET_STATE_SCHED,
  46         TASKLET_STATE_RUN
  47 };
  48
  49 /*
  50  * TODO: verify these points:
  51  * - tasklets that have the same type cannot be run on multiple processors at the same time
  52  * - tasklets always run on the processor from which they were originally
  53  *   submitted
  54  * - when a tasklet is scheduled, its state is set to TASKLET_STATE_SCHED, and the tasklet
  55  *   added to a queue
  56  * - during the execution of its function, the tasklet state is set to TASKLET_STATE_RUN
  57  *   and the TASKLET_STATE_SCHED state is removed
  58  */
  59
  60 /* XXX scheduling and execution should be handled separately */
  61 static inline void
  62 tasklet_schedule(struct tasklet_struct *t)
  63 {
  64         set_bit(TASKLET_STATE_SCHED, t->state);
  65
  66         lockmgr(&t->lock, LK_EXCLUSIVE);
  67         clear_bit(TASKLET_STATE_SCHED, t->state);
  68
  69         set_bit(TASKLET_STATE_RUN, t->state);
  70         t->func(t->data);
  71         clear_bit(TASKLET_STATE_RUN, t->state);
  72
  73         lockmgr(&t->lock, LK_RELEASE);
  74 }
  75
  76 /* This function ensures that the tasklet is not scheduled to run again */
  77 /* XXX this doesn't kill anything */
  78 static inline void
  79 tasklet_kill(struct tasklet_struct *t)
  80 {
  81         lockmgr(&t->lock, LK_EXCLUSIVE);
  82         clear_bit(TASKLET_STATE_SCHED, t->state);
  83         lockmgr(&t->lock, LK_RELEASE);
  84 }
  85
  86 static inline void
  87 tasklet_init(struct tasklet_struct *t, void (*func)(unsigned long), unsigned long data)
  88 {
  89         lockinit(&t->lock, "ltasklet", 0, LK_CANRECURSE);
  90         t->state = 0;
  91         t->func = func;
  92         t->data = data;
  93 }
  94
  95 #endif  /* _LINUX_INTERRUPT_H_ */