1 /* $OpenBSD: rkrng.c,v 1.3 2020/05/29 04:42:25 deraadt Exp $ */ 2 /* 3 * Copyright (c) 2020 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/ofw_clock.h> 28 #include <dev/ofw/fdt.h> 29 30 /* Registers */ 31 #define RNG_CTRL 0x0008 32 #define RNG_CTRL_START (1 << 8) 33 #define RNG_TRNG_CTRL 0x0200 34 #define RNG_TRNG_CTRL_OSC_ENABLE (1 << 16) 35 #define RNG_TRNG_CTRL_SAMPLE_PERIOD(x) (x) 36 #define RNG_DATA0 0x0204 37 38 #define HREAD4(sc, reg) \ 39 (bus_space_read_4((sc)->sc_iot, (sc)->sc_ioh, (reg))) 40 #define HWRITE4(sc, reg, val) \ 41 bus_space_write_4((sc)->sc_iot, (sc)->sc_ioh, (reg), (val)) 42 43 struct rkrng_softc { 44 struct device sc_dev; 45 bus_space_tag_t sc_iot; 46 bus_space_handle_t sc_ioh; 47 48 struct timeout sc_to; 49 int sc_started; 50 }; 51 52 int rkrng_match(struct device *, void *, void *); 53 void rkrng_attach(struct device *, struct device *, void *); 54 55 struct cfattach rkrng_ca = { 56 sizeof (struct rkrng_softc), rkrng_match, rkrng_attach 57 }; 58 59 struct cfdriver rkrng_cd = { 60 NULL, "rkrng", DV_DULL 61 }; 62 63 void rkrng_rnd(void *); 64 65 int 66 rkrng_match(struct device *parent, void *match, void *aux) 67 { 68 struct fdt_attach_args *faa = aux; 69 70 return OF_is_compatible(faa->fa_node, "rockchip,cryptov1-rng"); 71 } 72 73 void 74 rkrng_attach(struct device *parent, struct device *self, void *aux) 75 { 76 struct rkrng_softc *sc = (struct rkrng_softc *)self; 77 struct fdt_attach_args *faa = aux; 78 79 if (faa->fa_nreg < 1) { 80 printf(": no registers\n"); 81 return; 82 } 83 84 sc->sc_iot = faa->fa_iot; 85 if (bus_space_map(sc->sc_iot, faa->fa_reg[0].addr, 86 faa->fa_reg[0].size, 0, &sc->sc_ioh)) { 87 printf(": can't map registers\n"); 88 return; 89 } 90 91 printf("\n"); 92 93 clock_set_assigned(faa->fa_node); 94 clock_enable_all(faa->fa_node); 95 96 timeout_set(&sc->sc_to, rkrng_rnd, sc); 97 rkrng_rnd(sc); 98 } 99 100 void 101 rkrng_rnd(void *arg) 102 { 103 struct rkrng_softc *sc = arg; 104 bus_size_t off; 105 106 if (!sc->sc_started) { 107 HWRITE4(sc, RNG_TRNG_CTRL, RNG_TRNG_CTRL_OSC_ENABLE | 108 RNG_TRNG_CTRL_SAMPLE_PERIOD(100)); 109 HWRITE4(sc, RNG_CTRL, (RNG_CTRL_START << 16) | RNG_CTRL_START); 110 sc->sc_started = 1; 111 timeout_add_usec(&sc->sc_to, 100); 112 return; 113 } 114 115 if (HREAD4(sc, RNG_CTRL) & RNG_CTRL_START) { 116 timeout_add_usec(&sc->sc_to, 100); 117 return; 118 } 119 120 for (off = 0; off < 32; off += 4) 121 enqueue_randomness(HREAD4(sc, RNG_DATA0 + off)); 122 123 HWRITE4(sc, RNG_CTRL, (RNG_CTRL_START << 16) | 0); 124 sc->sc_started = 0; 125 126 timeout_add_sec(&sc->sc_to, 1); 127 } 128