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102 lines
3.1 KiB
C
102 lines
3.1 KiB
C
/* $NetBSD: bcm2835_mbox_subr.c,v 1.4 2014/10/07 08:30:05 skrll Exp $ */
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/*-
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* Copyright (c) 2012 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Nick Hudson
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: bcm2835_mbox_subr.c,v 1.4 2014/10/07 08:30:05 skrll Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/device.h>
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#include <sys/kernel.h>
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#include <sys/timetc.h>
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#include <sys/bus.h>
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#include <arm/broadcom/bcm_amba.h>
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#include <arm/broadcom/bcm2835_mbox.h>
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#include <arm/broadcom/bcm2835_mboxreg.h>
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#include <arm/broadcom/bcm2835reg.h>
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void
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bcm2835_mbox_read(bus_space_tag_t iot, bus_space_handle_t ioh, uint8_t chan,
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uint32_t *data)
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{
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uint32_t mbox;
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KASSERT((chan & 0xf) == chan);
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for (;;) {
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uint8_t rchan;
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uint32_t rdata;
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bus_space_barrier(iot, ioh, 0, BCM2835_MBOX_SIZE,
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BUS_SPACE_BARRIER_READ);
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if ((bus_space_read_4(iot, ioh,
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BCM2835_MBOX0_STATUS) & BCM2835_MBOX_STATUS_EMPTY) != 0)
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continue;
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mbox = bus_space_read_4(iot, ioh, BCM2835_MBOX0_READ);
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rchan = BCM2835_MBOX_CHAN(mbox);
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rdata = BCM2835_MBOX_DATA(mbox);
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if (rchan == chan) {
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*data = rdata;
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return;
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}
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}
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}
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void
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bcm2835_mbox_write(bus_space_tag_t iot, bus_space_handle_t ioh, uint8_t chan,
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uint32_t data)
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{
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uint32_t rdata;
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KASSERT((chan & 0xf) == chan);
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KASSERT((data & 0xf) == 0);
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for (;;) {
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bus_space_barrier(iot, ioh, 0, BCM2835_MBOX_SIZE,
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BUS_SPACE_BARRIER_READ);
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if ((rdata = bus_space_read_4(iot, ioh,
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BCM2835_MBOX0_STATUS) & BCM2835_MBOX_STATUS_FULL) == 0)
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break;
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}
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bus_space_write_4(iot, ioh, BCM2835_MBOX1_WRITE,
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BCM2835_MBOX_MSG(chan, data));
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bus_space_barrier(iot, ioh, 0, BCM2835_MBOX_SIZE,
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BUS_SPACE_BARRIER_WRITE);
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}
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