text: /*	$OpenBSD: softintr.c,v 1.7 2010/12/21 14:56:23 claudio Exp $	*/
  /*	$NetBSD: softintr.c,v 1.2 2003/07/15 00:24:39 lukem Exp $	*/
  
  /*
   * Copyright (c) 2001 Wasabi Systems, Inc.
   * All rights reserved.
   *
   * Written by Jason R. Thorpe for Wasabi Systems, Inc.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *	This product includes software developed for the NetBSD Project by
   *	Wasabi Systems, Inc.
   * 4. The name of Wasabi Systems, Inc. may not be used to endorse
   *    or promote products derived from this software without specific prior
   *    written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
   * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
   * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   */
  
  #include <sys/param.h>
  #include <sys/malloc.h>
  
  #include <uvm/uvm_extern.h>
  
  #include <machine/atomic.h>
  #include <machine/intr.h>
  
  struct soft_intrq soft_intrq[SI_NQUEUES];
  
  /*
   * softintr_init:
   *
   *	Initialize the software interrupt system.
   */
  void
  softintr_init(void)
  {
  	struct soft_intrq *siq;
  	int i;
  
  	for (i = 0; i < SI_NQUEUES; i++) {
  		siq = &soft_intrq[i];
  		TAILQ_INIT(&siq->siq_list);
  		mtx_init(&siq->siq_mtx, IPL_HIGH);
  		siq->siq_si = i;
  	}
  }
  
  /*
   * softintr_dispatch:
   *
   *	Process pending software interrupts on the specified queue.
   *
   *	NOTE: We must already be at the correct interrupt priority level.
   */
  void
  softintr_dispatch(int si)
  {
  	struct soft_intrq *siq = &soft_intrq[si];
  	struct soft_intrhand *sih;
  
  	for (;;) {
  		mtx_enter(&siq->siq_mtx);
  		sih = TAILQ_FIRST(&siq->siq_list);
  		if (sih == NULL) {
  			mtx_leave(&siq->siq_mtx);
  			break;
  		}
  
  		TAILQ_REMOVE(&siq->siq_list, sih, sih_list);
  		sih->sih_pending = 0;
  
  		uvmexp.softs++;
  		mtx_leave(&siq->siq_mtx);
  
  		(*sih->sih_func)(sih->sih_arg);
  	}
  }
  
  /*
   * softintr_establish:		[interface]
   *
   *	Register a software interrupt handler.
   */
  void *
  softintr_establish(int ipl, void (*func)(void *), void *arg)
  {
  	struct soft_intrhand *sih;
  	int si;
  
  	switch (ipl) {
  	case IPL_SOFT:
  		si = SI_SOFT;
  		break;
  
  	case IPL_SOFTCLOCK:
  		si = SI_SOFTCLOCK;
  		break;
  
  	case IPL_SOFTNET:
  		si = SI_SOFTNET;
  		break;
  
  	case IPL_TTY:
  	case IPL_SOFTTTY:
  		si = SI_SOFTTTY;
  		break;
  
  	default:
  		panic("softintr_establish: unknown soft IPL %d", ipl);
  	}
  
  	sih = malloc(sizeof(*sih), M_DEVBUF, M_NOWAIT);
  	if (__predict_true(sih != NULL)) {
  		sih->sih_func = func;
  		sih->sih_arg = arg;
  		sih->sih_siq = &soft_intrq[si];
  		sih->sih_pending = 0;
  	}
  	return (sih);
  }
  
  /*
   * softintr_disestablish:	[interface]
   *
   *	Unregister a software interrupt handler.
   */
  void
  softintr_disestablish(void *arg)
  {
  	struct soft_intrhand *sih = arg;
  	struct soft_intrq *siq = sih->sih_siq;
  
  	mtx_enter(&siq->siq_mtx);
  	if (sih->sih_pending) {
  		TAILQ_REMOVE(&siq->siq_list, sih, sih_list);
  		sih->sih_pending = 0;
  	}
  	mtx_leave(&siq->siq_mtx);
  
  	free(sih, M_DEVBUF);
  }
  