1 /* $NetBSD: bcm2835_mbox_subr.c,v 1.3 2012/10/13 08:42:50 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 1.3 2012/10/13 08:42:50 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 48 #define BCM2835_MBOX_CHAN(chan) ((chan) & 0xf) 49 #define BCM2835_MBOX_DATA(data) ((data) & ~0xf) 50 51 #define BCM2835_MBOX_MSG(chan, data) (((chan) & 0xf) | ((data) & ~0xf)) 52 53 void 54 bcm2835_mbox_read(bus_space_tag_t iot, bus_space_handle_t ioh, uint8_t chan, 55 uint32_t *data) 56 { 57 uint32_t mbox; 58 59 KASSERT((chan & 0xf) == chan); 60 61 for (;;) { 62 uint8_t rchan; 63 uint32_t rdata; 64 65 bus_space_barrier(iot, ioh, 0, BCM2835_MBOX_SIZE, 66 BUS_SPACE_BARRIER_READ); 67 68 if ((bus_space_read_4(iot, ioh, 69 BCM2835_MBOX0_STATUS) & BCM2835_MBOX_STATUS_EMPTY) != 0) 70 continue; 71 72 mbox = bus_space_read_4(iot, ioh, BCM2835_MBOX0_READ); 73 74 rchan = BCM2835_MBOX_CHAN(mbox); 75 rdata = BCM2835_MBOX_DATA(mbox); 76 77 if (rchan == chan) { 78 *data = rdata; 79 return; 80 } 81 } 82 } 83 84 void 85 bcm2835_mbox_write(bus_space_tag_t iot, bus_space_handle_t ioh, uint8_t chan, 86 uint32_t data) 87 { 88 uint32_t rdata; 89 90 KASSERT((chan & 0xf) == chan); 91 KASSERT((data & 0xf) == 0); 92 for (;;) { 93 94 bus_space_barrier(iot, ioh, 0, BCM2835_MBOX_SIZE, 95 BUS_SPACE_BARRIER_READ); 96 97 if ((rdata = bus_space_read_4(iot, ioh, 98 BCM2835_MBOX0_STATUS) & BCM2835_MBOX_STATUS_FULL) == 0) 99 break; 100 } 101 102 bus_space_write_4(iot, ioh, BCM2835_MBOX1_WRITE, 103 BCM2835_MBOX_MSG(chan, data)); 104 105 bus_space_barrier(iot, ioh, 0, BCM2835_MBOX_SIZE, 106 BUS_SPACE_BARRIER_WRITE); 107 } 108