1 /* $NetBSD: rng200.c,v 1.4 2022/03/19 11:55:03 riastradh Exp $ */
2
3 /*
4 * Copyright (c) 2019 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Michael van Elst
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 /*
33 * Driver for the Broadcom iProc RNG200
34 */
35
36 #include <sys/param.h>
37 #include <sys/bus.h>
38 #include <sys/mutex.h>
39 #include <sys/rndsource.h>
40
41 #include <dev/ic/rng200var.h>
42 #include <dev/ic/rng200reg.h>
43
44 #define READ4(sc, r) \
45 bus_space_read_4((sc)->sc_bst, (sc)->sc_bsh, (r))
46
47 #define WRITE4(sc, r, v) \
48 bus_space_write_4((sc)->sc_bst, (sc)->sc_bsh, (r), (v))
49
50 static void
rng200_reset(struct rng200_softc * sc)51 rng200_reset(struct rng200_softc *sc)
52 {
53 uint32_t ctl, rng, rbg;
54
55 /* Disable RBG */
56 ctl = READ4(sc, RNG200_CONTROL);
57 ctl &= ~RNG200_RBG_MASK;
58 WRITE4(sc, RNG200_CONTROL, ctl);
59
60 /* Clear interrupts */
61 WRITE4(sc, RNG200_STATUS, 0xffffffff);
62
63 /* Reset RNG and RBG */
64 rbg = READ4(sc, RNG200_RBG_RESET);
65 rng = READ4(sc, RNG200_RNG_RESET);
66 WRITE4(sc, RNG200_RBG_RESET, rbg | RBG_RESET);
67 WRITE4(sc, RNG200_RNG_RESET, rng | RNG_RESET);
68 WRITE4(sc, RNG200_RNG_RESET, rng);
69 WRITE4(sc, RNG200_RBG_RESET, rbg);
70
71 /* Enable RBG */
72 WRITE4(sc, RNG200_CONTROL, ctl | RNG200_RBG_ENABLE);
73 }
74
75 static void
rng200_get(size_t bytes_wanted,void * priv)76 rng200_get(size_t bytes_wanted, void *priv)
77 {
78 struct rng200_softc * const sc = priv;
79 uint32_t w, data;
80 unsigned count;
81
82 while (bytes_wanted) {
83
84 w = READ4(sc, RNG200_STATUS);
85 if ((w & (RNG200_MASTER_FAIL | RNG200_NIST_FAIL)) != 0)
86 rng200_reset(sc);
87
88 w = READ4(sc, RNG200_COUNT);
89 count = __SHIFTOUT(w, RNG200_COUNT_MASK);
90
91 if (count == 0)
92 break;
93
94 data = READ4(sc, RNG200_DATA);
95 rnd_add_data_sync(&sc->sc_rndsource, &data,
96 sizeof(data), sizeof(data) * NBBY);
97 bytes_wanted -= MIN(bytes_wanted, sizeof(data));
98 }
99 explicit_memset(&data, 0, sizeof(data));
100 }
101
102 void
rng200_attach(struct rng200_softc * sc)103 rng200_attach(struct rng200_softc *sc)
104 {
105
106 rndsource_setcb(&sc->sc_rndsource, rng200_get, sc);
107 rnd_attach_source(&sc->sc_rndsource, sc->sc_name,
108 RND_TYPE_RNG, RND_FLAG_COLLECT_VALUE|RND_FLAG_HASCB);
109 }
110
111 void
rng200_detach(struct rng200_softc * sc)112 rng200_detach(struct rng200_softc *sc)
113 {
114
115 rnd_detach_source(&sc->sc_rndsource);
116 }
117
118