11.1Sreinoud/* $NetBSD: interrupts,v 1.1 2001/10/18 00:05:01 reinoud Exp $ */
21.1Sreinoud
31.1Sreinoud/*
41.1Sreinoud * Copyright (c) 1996 Mark Brinicombe.
51.1Sreinoud * All rights reserved.
61.1Sreinoud *
71.1Sreinoud * Redistribution and use in source and binary forms, with or without
81.1Sreinoud * modification, are permitted provided that the following conditions
91.1Sreinoud * are met:
101.1Sreinoud * 1. Redistributions of source code must retain the above copyright
111.1Sreinoud *    notice, this list of conditions and the following disclaimer.
121.1Sreinoud * 2. Redistributions in binary form must reproduce the above copyright
131.1Sreinoud *    notice, this list of conditions and the following disclaimer in the
141.1Sreinoud *    documentation and/or other materials provided with the distribution.
151.1Sreinoud * 3. All advertising materials mentioning features or use of this software
161.1Sreinoud *    must display the following acknowledgement:
171.1Sreinoud *	This product includes software developed by Mark Brinicombe.
181.1Sreinoud * 4. The name of the company nor the name of the author may be used to
191.1Sreinoud *    endorse or promote products derived from this software without specific
201.1Sreinoud *    prior written permission.
211.1Sreinoud *
221.1Sreinoud * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
231.1Sreinoud * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
241.1Sreinoud * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
251.1Sreinoud * IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
261.1Sreinoud * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
271.1Sreinoud * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
281.1Sreinoud * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
291.1Sreinoud * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
301.1Sreinoud * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
311.1Sreinoud * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
321.1Sreinoud * SUCH DAMAGE.
331.1Sreinoud */
341.1Sreinoud
351.1SreinoudNotes on interrupts.
361.1Sreinoud
371.1SreinoudOk since interrupts can be chained the return value from an interrupt
381.1Sreinoudhandler is important.
391.1Sreinoud
401.1SreinoudThe following return values are defined :
411.1Sreinoud
421.1Sreinoud-1	- interrupt may have been for us but not sure so pass it on
431.1Sreinoud0	- interrupt no serviced (not ours)
441.1Sreinoud	  interrupt serviced but pass on down the chain
451.1Sreinoud1	- interrupt serviced do not pass on down the chain
461.1Sreinoud
471.1SreinoudThe important bit is whether the interrupt should be passed on down
481.1Sreinoudthe chain of attached interrupt handlers.
491.1Sreinoud
501.1SreinoudFor some interrupts and drivers where only a single device is
511.1Sreinoudever expected, the interrupt should be claimed if it has been serviced.
521.1SreinoudPassing it on down the chain may result in the stray interrupt handler
531.1Sreinoudbeing called.
541.1SreinoudThere are however some interrupt that should *always* be passed on down
551.1Sreinoudthe chain. These are interrupt which may commonly have multiple drivers
561.1Sreinoudattached.
571.1Sreinoud
581.1SreinoudThe following interrupts should always be passed on (return value of 0)
591.1Sreinoud
601.1SreinoudIRQ_TIMER0	
611.1SreinoudIRQ_TIMER1	
621.1SreinoudIRQ_VSYNC
631.1SreinoudIRQ_FLYBACK
641.1SreinoudIRQ_PODULE
651.1Sreinoud
661.1SreinoudIRQ_CLOCK	(RC7500)
671.1Sreinoud
681.1SreinoudThe following interrupts are recommended to be passed on
691.1Sreinoud
701.1SreinoudIRQ_DMACH0
711.1SreinoudIRQ_DMACH1
721.1SreinoudIRQ_DMACH2
731.1SreinoudIRQ_DMACH3
741.1SreinoudIRQ_DMASCH0
751.1SreinoudIRQ_DMASCH1
761.1Sreinoud
771.1SreinoudIRQ_SDMA	(RC7500)
781.1Sreinoud
791.1SreinoudAll other interrupts are not expected to be shared and may be claimed
801.1Sreinoudwhen serviced. Stray IRQ handlers may or may not be attached to the end
811.1Sreinoudof these irq chains.
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