1 /* $NetBSD: bcm2835_mbox_subr.c,v 1.4 2014/10/07 08:30:05 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_subr.c,v 1.4 2014/10/07 08:30:05 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 void 48 bcm2835_mbox_read(bus_space_tag_t iot, bus_space_handle_t ioh, uint8_t chan, 49 uint32_t *data) 50 { 51 uint32_t mbox; 52 53 KASSERT((chan & 0xf) == chan); 54 55 for (;;) { 56 uint8_t rchan; 57 uint32_t rdata; 58 59 bus_space_barrier(iot, ioh, 0, BCM2835_MBOX_SIZE, 60 BUS_SPACE_BARRIER_READ); 61 62 if ((bus_space_read_4(iot, ioh, 63 BCM2835_MBOX0_STATUS) & BCM2835_MBOX_STATUS_EMPTY) != 0) 64 continue; 65 66 mbox = bus_space_read_4(iot, ioh, BCM2835_MBOX0_READ); 67 68 rchan = BCM2835_MBOX_CHAN(mbox); 69 rdata = BCM2835_MBOX_DATA(mbox); 70 71 if (rchan == chan) { 72 *data = rdata; 73 return; 74 } 75 } 76 } 77 78 void 79 bcm2835_mbox_write(bus_space_tag_t iot, bus_space_handle_t ioh, uint8_t chan, 80 uint32_t data) 81 { 82 uint32_t rdata; 83 84 KASSERT((chan & 0xf) == chan); 85 KASSERT((data & 0xf) == 0); 86 for (;;) { 87 88 bus_space_barrier(iot, ioh, 0, BCM2835_MBOX_SIZE, 89 BUS_SPACE_BARRIER_READ); 90 91 if ((rdata = bus_space_read_4(iot, ioh, 92 BCM2835_MBOX0_STATUS) & BCM2835_MBOX_STATUS_FULL) == 0) 93 break; 94 } 95 96 bus_space_write_4(iot, ioh, BCM2835_MBOX1_WRITE, 97 BCM2835_MBOX_MSG(chan, data)); 98 99 bus_space_barrier(iot, ioh, 0, BCM2835_MBOX_SIZE, 100 BUS_SPACE_BARRIER_WRITE); 101 } 102