1 /* $OpenBSD: amlrng.c,v 1.3 2021/10/24 17:52:26 mpi Exp $ */
2 /*
3 * Copyright (c) 2019 Mark Kettenis <kettenis@openbsd.org>
4 *
5 * Permission to use, copy, modify, and 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/bus.h>
24 #include <machine/fdt.h>
25
26 #include <dev/ofw/openfirm.h>
27 #include <dev/ofw/fdt.h>
28
29 /* Registers */
30 #define RNG_DATA 0x0000
31
32 #define HREAD4(sc, reg) \
33 (bus_space_read_4((sc)->sc_iot, (sc)->sc_ioh, (reg)))
34
35 struct amlrng_softc {
36 struct device sc_dev;
37 bus_space_tag_t sc_iot;
38 bus_space_handle_t sc_ioh;
39
40 struct timeout sc_to;
41 };
42
43 int amlrng_match(struct device *, void *, void *);
44 void amlrng_attach(struct device *, struct device *, void *);
45
46 const struct cfattach amlrng_ca = {
47 sizeof (struct amlrng_softc), amlrng_match, amlrng_attach
48 };
49
50 struct cfdriver amlrng_cd = {
51 NULL, "amlrng", DV_DULL
52 };
53
54 void amlrng_rnd(void *);
55
56 int
amlrng_match(struct device * parent,void * match,void * aux)57 amlrng_match(struct device *parent, void *match, void *aux)
58 {
59 struct fdt_attach_args *faa = aux;
60
61 return OF_is_compatible(faa->fa_node, "amlogic,meson-rng");
62 }
63
64 void
amlrng_attach(struct device * parent,struct device * self,void * aux)65 amlrng_attach(struct device *parent, struct device *self, void *aux)
66 {
67 struct amlrng_softc *sc = (struct amlrng_softc *)self;
68 struct fdt_attach_args *faa = aux;
69
70 if (faa->fa_nreg < 1) {
71 printf(": no registers\n");
72 return;
73 }
74
75 sc->sc_iot = faa->fa_iot;
76 if (bus_space_map(sc->sc_iot, faa->fa_reg[0].addr,
77 faa->fa_reg[0].size, 0, &sc->sc_ioh)) {
78 printf(": can't map registers\n");
79 return;
80 }
81
82 printf("\n");
83
84 timeout_set(&sc->sc_to, amlrng_rnd, sc);
85 amlrng_rnd(sc);
86 }
87
88 void
amlrng_rnd(void * arg)89 amlrng_rnd(void *arg)
90 {
91 struct amlrng_softc *sc = arg;
92
93 enqueue_randomness(HREAD4(sc, RNG_DATA));
94 timeout_add_sec(&sc->sc_to, 1);
95 }
96