1 /* $OpenBSD: qcrng.c,v 1.1 2023/04/28 05:13:37 phessler 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 #define RNG_STATUS 0x0004
32
33 #define HREAD4(sc, reg) \
34 (bus_space_read_4((sc)->sc_iot, (sc)->sc_ioh, (reg)))
35
36 struct qcrng_softc {
37 struct device sc_dev;
38 bus_space_tag_t sc_iot;
39 bus_space_handle_t sc_ioh;
40
41 struct timeout sc_to;
42 };
43
44 int qcrng_match(struct device *, void *, void *);
45 void qcrng_attach(struct device *, struct device *, void *);
46
47 const struct cfattach qcrng_ca = {
48 sizeof (struct qcrng_softc), qcrng_match, qcrng_attach
49 };
50
51 struct cfdriver qcrng_cd = {
52 NULL, "qcrng", DV_DULL
53 };
54
55 void qcrng_rnd(void *);
56
57 int
qcrng_match(struct device * parent,void * match,void * aux)58 qcrng_match(struct device *parent, void *match, void *aux)
59 {
60 struct fdt_attach_args *faa = aux;
61
62 return OF_is_compatible(faa->fa_node, "qcom,prng-ee");
63 }
64
65 void
qcrng_attach(struct device * parent,struct device * self,void * aux)66 qcrng_attach(struct device *parent, struct device *self, void *aux)
67 {
68 struct qcrng_softc *sc = (struct qcrng_softc *)self;
69 struct fdt_attach_args *faa = aux;
70
71 if (faa->fa_nreg < 1) {
72 printf(": no registers\n");
73 return;
74 }
75
76 sc->sc_iot = faa->fa_iot;
77 if (bus_space_map(sc->sc_iot, faa->fa_reg[0].addr,
78 faa->fa_reg[0].size, 0, &sc->sc_ioh)) {
79 printf(": can't map registers\n");
80 return;
81 }
82
83 printf("\n");
84
85 timeout_set(&sc->sc_to, qcrng_rnd, sc);
86 qcrng_rnd(sc);
87 }
88
89 void
qcrng_rnd(void * arg)90 qcrng_rnd(void *arg)
91 {
92 struct qcrng_softc *sc = arg;
93
94 if (HREAD4(sc, RNG_STATUS) & 0x1)
95 enqueue_randomness(HREAD4(sc, RNG_DATA));
96
97 timeout_add_sec(&sc->sc_to, 1);
98 }
99