1 /* $OpenBSD: octrng.c,v 1.10 2022/04/06 18:59:27 naddy Exp $ */
2 /*
3 * Copyright (c) 2013 Paul Irofti <paul@irofti.net>
4 *
5 * Permission to use, copy, modify, and/or distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18 #include <sys/param.h>
19 #include <sys/systm.h>
20 #include <sys/device.h>
21 #include <sys/timeout.h>
22
23 #include <machine/octeonvar.h>
24 #include <machine/octeonreg.h>
25 #include <octeon/dev/iobusvar.h>
26
27 int octrng_match(struct device *, void *, void *);
28 void octrng_attach(struct device *, struct device *, void *);
29 void octrng_rnd(void *arg);
30
31 #ifdef OCTRNG_DEBUG
32 #define DPRINTF(x) printf x
33 #else
34 #define DPRINTF(x)
35 #endif
36
37 #define OCTRNG_MAP_SIZE 8ULL
38
39 /* OCTRNG_ENTROPY_ADDR 0x8001400000000000ULL */
40 #define OCTRNG_MAJORDID 8ULL
41 #define OCTRNG_ENTROPY_ADDR (((uint64_t)1 << 48) | \
42 ((uint64_t)(OCTRNG_MAJORDID & 0x1f) << 43))
43 #define OCTRNG_ENTROPY_REG 0
44
45 #define OCTRNG_CONTROL_ADDR 0x0001180040000000ULL
46
47 #define OCTRNG_RESET (1ULL << 3)
48 #define OCTRNG_ENABLE_OUTPUT (1ULL << 1)
49 #define OCTRNG_ENABLE_ENTROPY (1ULL << 0)
50
51 struct octrng_softc {
52 struct device sc_dev;
53 struct timeout sc_to;
54 struct iobus_attach_args *sc_io;
55
56 bus_space_tag_t sc_iot;
57 bus_space_handle_t sc_ioh;
58 };
59
60 const struct cfattach octrng_ca = {
61 sizeof(struct octrng_softc), octrng_match, octrng_attach
62 };
63
64 struct cfdriver octrng_cd = {
65 NULL, "octrng", DV_DULL
66 };
67
68
69 int
octrng_match(struct device * parent,void * match,void * aux)70 octrng_match(struct device *parent, void *match, void *aux)
71 {
72 struct iobus_attach_args *aa = aux;
73 struct cfdata *cf = match;
74
75 /* XXX: check for board type */
76
77 if (strcmp(aa->aa_name, cf->cf_driver->cd_name) != 0)
78 return (0);
79
80 return (1);
81 }
82
83 void
octrng_attach(struct device * parent,struct device * self,void * aux)84 octrng_attach(struct device *parent, struct device *self, void *aux)
85 {
86 struct octrng_softc *sc = (void *)self;
87 sc->sc_io = aux;
88
89 uint64_t control_reg;
90
91 sc->sc_iot = sc->sc_io->aa_bust;
92
93 if (bus_space_map(sc->sc_iot, OCTEON_RNG_BASE, OCTRNG_MAP_SIZE, 0,
94 &sc->sc_ioh)) {
95 printf(": can't map registers");
96 }
97
98 control_reg = octeon_xkphys_read_8(OCTRNG_CONTROL_ADDR);
99 control_reg |= (OCTRNG_ENABLE_OUTPUT | OCTRNG_ENABLE_ENTROPY);
100 octeon_xkphys_write_8(OCTRNG_CONTROL_ADDR, control_reg);
101
102 timeout_set(&sc->sc_to, octrng_rnd, sc);
103
104 timeout_add_sec(&sc->sc_to, 5);
105
106 printf("\n");
107 }
108
109 void
octrng_rnd(void * arg)110 octrng_rnd(void *arg)
111 {
112 struct octrng_softc *sc = arg;
113 uint64_t value;
114
115 value = bus_space_read_8(sc->sc_iot, sc->sc_ioh, OCTRNG_ENTROPY_REG);
116
117 DPRINTF(("%#llX ", value)); /* WARNING: very verbose */
118
119 enqueue_randomness(value);
120 timeout_add_msec(&sc->sc_to, 10);
121 }
122