FreeBSD/Linux Kernel Cross Reference
sys/dev/podulebus/acemidi.c

     /* $NetBSD: acemidi.c,v 1.7 2002/10/02 16:52:23 thorpej Exp $ */
     
     /*-
      * Copyright (c) 2001 Ben Harris
      * All rights reserved.
      *
      * 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. The name of the author may not be used to endorse or promote products
     *    derived from this software without specific prior written permission.
     * 
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 THE AUTHOR 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/cdefs.h>
    __KERNEL_RCSID(0, "$NetBSD: acemidi.c,v 1.7 2002/10/02 16:52:23 thorpej Exp $");
    
    #include <sys/param.h>
    
    #include <sys/device.h>
    #include <sys/systm.h>
    
    #include <machine/bus.h>
    
    #include <dev/podulebus/podulebus.h>
    #include <dev/podulebus/podules.h>
    #include <dev/podulebus/acemidireg.h>
    
    #include <sys/termios.h>
    #include <dev/ic/comvar.h>
    #include <dev/ic/comreg.h>
    
    struct acemidi_softc {
            struct          device sc_dev;
    };
    
    struct com_acemidi_softc {
            struct          com_softc sc_com;
            struct          evcnt sc_intrcnt;
    };
    
    static int acemidi_match(struct device *, struct cfdata *, void *);
    static void acemidi_attach(struct device *, struct device *, void *);
    static int com_acemidi_match(struct device *, struct cfdata *, void *);
    static void com_acemidi_attach(struct device *, struct device *, void *);
    
    CFATTACH_DECL(acemidi, sizeof(struct acemidi_softc),
        acemidi_match, acemidi_attach, NULL, NULL);
    
    CFATTACH_DECL(com_acemidi, sizeof(struct com_acemidi_softc),
        com_acemidi_match, com_acemidi_attach, NULL, NULL);
    
    static int
    acemidi_match(struct device *parent, struct cfdata *cf, void *aux)
    {
            struct podulebus_attach_args *pa = aux;
    
            if (pa->pa_product == PODULE_MIDICONNECT)
                    return 1;
            return 0;
    }
    
    static void
    acemidi_attach(struct device *parent, struct device *self, void *aux)
    {
    /*      struct acemidi_softc *sc = (void *)self; */
    /*      struct podulebus_attach_args *pa = aux; */
    
            printf("\n");
            config_found_sm(self, aux, NULL, NULL);
    }
    
    static int
    com_acemidi_match(struct device *parent, struct cfdata *cf, void *aux)
    {
    
            return 1;
    }
    
    static void
    com_acemidi_attach(struct device *parent, struct device *self, void *aux)
    {
            struct com_acemidi_softc *sc = (void *)self;
            struct com_softc *csc = &sc->sc_com;
           struct podulebus_attach_args *pa = aux;
   
           csc->sc_iobase = pa->pa_fast_base + ACEMIDI_16550_BASE;
           csc->sc_iot = pa->pa_fast_t;
           bus_space_map(csc->sc_iot, csc->sc_iobase, COM_NPORTS, 0,
               &csc->sc_ioh);
           csc->sc_frequency = ACEMIDI_16550_FREQ;
   
           com_attach_subr(csc);
   
           evcnt_attach_dynamic(&sc->sc_intrcnt, EVCNT_TYPE_INTR, NULL,
               self->dv_xname, "intr");
           podulebus_irq_establish(pa->pa_ih, IPL_SERIAL, comintr, sc,
               &sc->sc_intrcnt);
   }
   
   /*
    * Stray IRQ bug:
    * 
    * Occasionally, when receiving, we get a stray IRQ.  Sometimes, the interrupt
    * bit on the unixbp reads as clear.  In any case, comintr() gets an IIR
    * of 0xc1 (no interrupts pending).
    *
    * The behaviour can be observed with a logic probe:
    *
    * Channel 1 to PIRQ* (pin 19 on IC3 on A540 backplane)
    * Channel 2 to INTR on 16550
    * trigger on ch1 low, ch2 falling
    * 2 us/div
    *
    * This catches cases where the 16550 de-asserts the interrupt before
    * irq_handler is entered and disables the interrupt at unixbp (by calling
    * splhigh()).
    *
    * This gets us 5us pulses on INTR and PIRQ*.  Now to work out why.
    *
    * Connecting channel 3 to the CS2* pin on the 16550 shows it high throughout,
    * so the interrupt isn't being cleared by the host.  MR, similarly, is low
    * throughout, so it's not being cleared by a reset.
    */

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