1 /* $NetBSD: bcm2835_mbox_subr.c,v 1.5 2017/12/10 21:38:26 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 1.5 2017/12/10 21:38:26 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/bcm2835_mbox.h>
43 #include <arm/broadcom/bcm2835_mboxreg.h>
44 #include <arm/broadcom/bcm2835reg.h>
45
46 void
bcm2835_mbox_read(bus_space_tag_t iot,bus_space_handle_t ioh,uint8_t chan,uint32_t * data)47 bcm2835_mbox_read(bus_space_tag_t iot, bus_space_handle_t ioh, uint8_t chan,
48 uint32_t *data)
49 {
50 uint32_t mbox;
51
52 KASSERT((chan & 0xf) == chan);
53
54 for (;;) {
55 uint8_t rchan;
56 uint32_t rdata;
57
58 bus_space_barrier(iot, ioh, 0, BCM2835_MBOX_SIZE,
59 BUS_SPACE_BARRIER_READ);
60
61 if ((bus_space_read_4(iot, ioh,
62 BCM2835_MBOX0_STATUS) & BCM2835_MBOX_STATUS_EMPTY) != 0)
63 continue;
64
65 mbox = bus_space_read_4(iot, ioh, BCM2835_MBOX0_READ);
66
67 rchan = BCM2835_MBOX_CHAN(mbox);
68 rdata = BCM2835_MBOX_DATA(mbox);
69
70 if (rchan == chan) {
71 *data = rdata;
72 return;
73 }
74 }
75 }
76
77 void
bcm2835_mbox_write(bus_space_tag_t iot,bus_space_handle_t ioh,uint8_t chan,uint32_t data)78 bcm2835_mbox_write(bus_space_tag_t iot, bus_space_handle_t ioh, uint8_t chan,
79 uint32_t data)
80 {
81 uint32_t rdata;
82
83 KASSERT((chan & 0xf) == chan);
84 KASSERT((data & 0xf) == 0);
85 for (;;) {
86
87 bus_space_barrier(iot, ioh, 0, BCM2835_MBOX_SIZE,
88 BUS_SPACE_BARRIER_READ);
89
90 if ((rdata = bus_space_read_4(iot, ioh,
91 BCM2835_MBOX0_STATUS) & BCM2835_MBOX_STATUS_FULL) == 0)
92 break;
93 }
94
95 bus_space_write_4(iot, ioh, BCM2835_MBOX1_WRITE,
96 BCM2835_MBOX_MSG(chan, data));
97
98 bus_space_barrier(iot, ioh, 0, BCM2835_MBOX_SIZE,
99 BUS_SPACE_BARRIER_WRITE);
100 }
101