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bcm2835_mbox.c revision 1.1 
      1 /*	$NetBSD: bcm2835_mbox.c,v 1.1 2012/08/20 07:45:24 skrll Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2012 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Nick Hudson
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 __KERNEL_RCSID(0, "$NetBSD: bcm2835_mbox.c,v 1.1 2012/08/20 07:45:24 skrll Exp $");
     34 
     35 #include <sys/param.h>
     36 #include <sys/systm.h>
     37 #include <sys/device.h>
     38 #include <sys/kernel.h>
     39 #include <sys/timetc.h>
     40 #include <sys/bus.h>
     41 
     42 #include <arm/broadcom/bcm_amba.h>
     43 #include <arm/broadcom/bcm2835_mbox.h>
     44 #include <arm/broadcom/bcm2835_mboxreg.h>
     45 #include <arm/broadcom/bcm2835reg.h>
     46 
     47 struct bcm2835mbox_softc {
     48 	device_t sc_dev;
     49 
     50 	bus_space_tag_t sc_iot;
     51 	bus_space_handle_t sc_ioh;
     52 };
     53 
     54 static struct bcm2835mbox_softc *bcm2835mbox_sc;
     55 
     56 static int bcmmbox_match(device_t, cfdata_t, void *);
     57 static void bcmmbox_attach(device_t, device_t, void *);
     58 
     59 CFATTACH_DECL_NEW(bcmmbox, sizeof(struct bcm2835mbox_softc),
     60     bcmmbox_match, bcmmbox_attach, NULL, NULL);
     61 
     62 /* ARGSUSED */
     63 static int
     64 bcmmbox_match(device_t parent, cfdata_t match, void *aux)
     65 {
     66 	struct amba_attach_args *aaa = aux;
     67 
     68 	if (strcmp(aaa->aaa_name, "bcmmbox") != 0)
     69 		return 0;
     70 
     71 	return 1;
     72 }
     73 
     74 static void
     75 bcmmbox_attach(device_t parent, device_t self, void *aux)
     76 {
     77         struct bcm2835mbox_softc *sc = device_private(self);
     78  	struct amba_attach_args *aaa = aux;
     79 
     80 	aprint_naive("\n");
     81 	aprint_normal(": VC mailbox\n");
     82 
     83 	if (bcm2835mbox_sc == NULL)
     84 		bcm2835mbox_sc = sc;
     85 
     86 	sc->sc_dev = self;
     87 	sc->sc_iot = aaa->aaa_iot;
     88 
     89 	if (bus_space_map(aaa->aaa_iot, aaa->aaa_addr, BCM2835_MBOX_SIZE, 0,
     90 	    &sc->sc_ioh)) {
     91 		aprint_error_dev(sc->sc_dev, "unable to map device\n");
     92 		return;
     93 	}
     94 }
     95 
     96 void
     97 bcmmbox_read(uint8_t chan, uint32_t *data)
     98 {
     99 	struct bcm2835mbox_softc *sc = bcm2835mbox_sc;
    100 	uint32_t mbox;
    101 
    102 	KASSERT(sc != NULL);
    103 
    104 	for (;;) {
    105 		uint8_t rchan;
    106 		uint32_t rdata;
    107 
    108 		bus_space_barrier(sc->sc_iot, sc->sc_ioh, 0,
    109 		    BCM2835_MBOX_SIZE, BUS_SPACE_BARRIER_READ);
    110 
    111 		if ((bus_space_read_4(sc->sc_iot, sc->sc_ioh,
    112 		    BCM2835_MBOX0_STATUS) & BCM2835_MBOX_STATUS_EMPTY) != 0)
    113 			continue;
    114 
    115 		mbox = bus_space_read_4(sc->sc_iot, sc->sc_ioh,
    116 		    BCM2835_MBOX0_READ);
    117 
    118 		rchan = BCM2835_MBOX_CHAN(mbox);
    119 		rdata = BCM2835_MBOX_DATA(mbox);
    120 
    121 		if (rchan == chan) {
    122 			*data = rdata;
    123 			return;
    124 		}
    125 	}
    126 }
    127 
    128 void
    129 bcmmbox_write(uint8_t chan, uint32_t data)
    130 {
    131 	struct bcm2835mbox_softc *sc = bcm2835mbox_sc;
    132 
    133 	KASSERT(sc != NULL);
    134 	uint32_t rdata;
    135 
    136 	for (;;) {
    137 
    138 		bus_space_barrier(sc->sc_iot, sc->sc_ioh, 0,
    139 		    BCM2835_MBOX_SIZE, BUS_SPACE_BARRIER_READ);
    140 
    141 		if ((rdata = bus_space_read_4(sc->sc_iot, sc->sc_ioh,
    142 		    BCM2835_MBOX0_STATUS) & BCM2835_MBOX_STATUS_FULL) == 0)
    143 			break;
    144 	}
    145 
    146 	bus_space_write_4(sc->sc_iot, sc->sc_ioh,
    147 	    BCM2835_MBOX1_WRITE, BCM2835_MBOX_MSG(chan, data));
    148 
    149 	bus_space_barrier(sc->sc_iot, sc->sc_ioh, 0,
    150 	    BCM2835_MBOX_SIZE, BUS_SPACE_BARRIER_WRITE);
    151 }
    152