| 1 | /* $NetBSD: fwhrng.c,v 1.9 2015/04/13 16:03:51 riastradh Exp $ */ |
| 2 | |
| 3 | /* |
| 4 | * Copyright (c) 2000 Michael Shalayeff |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * Redistribution and use in source and binary forms, with or without |
| 8 | * modification, are permitted provided that the following conditions |
| 9 | * are met: |
| 10 | * 1. Redistributions of source code must retain the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer. |
| 12 | * 2. Redistributions in binary form must reproduce the above copyright |
| 13 | * notice, this list of conditions and the following disclaimer in the |
| 14 | * documentation and/or other materials provided with the distribution. |
| 15 | * |
| 16 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 17 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 18 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 19 | * IN NO EVENT SHALL THE AUTHOR OR HIS RELATIVES BE LIABLE FOR ANY DIRECT, |
| 20 | * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| 21 | * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR |
| 22 | * SERVICES; LOSS OF MIND, USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 23 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| 24 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING |
| 25 | * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF |
| 26 | * THE POSSIBILITY OF SUCH DAMAGE. |
| 27 | * |
| 28 | * from OpenBSD: pchb.c,v 1.23 2000/10/23 20:07:30 deraadt Exp |
| 29 | */ |
| 30 | |
| 31 | #include <sys/cdefs.h> |
| 32 | __KERNEL_RCSID(0, "$NetBSD: fwhrng.c,v 1.9 2015/04/13 16:03:51 riastradh Exp $" ); |
| 33 | |
| 34 | #include <sys/param.h> |
| 35 | #include <sys/systm.h> |
| 36 | #include <sys/device.h> |
| 37 | #include <sys/time.h> |
| 38 | #include <sys/rndsource.h> |
| 39 | |
| 40 | #include <sys/bus.h> |
| 41 | |
| 42 | #include <arch/x86/pci/i82802reg.h> |
| 43 | |
| 44 | struct fwhrng_softc { |
| 45 | device_t sc_dev; |
| 46 | |
| 47 | bus_space_tag_t sc_st; |
| 48 | bus_space_handle_t sc_sh; |
| 49 | |
| 50 | struct callout sc_rnd_ch; |
| 51 | krndsource_t sc_rnd_source; |
| 52 | |
| 53 | int sc_rnd_i; |
| 54 | uint32_t sc_rnd_ax; |
| 55 | }; |
| 56 | |
| 57 | static int fwhrng_match(device_t, cfdata_t, void *); |
| 58 | static void fwhrng_attach(device_t, device_t, void *); |
| 59 | static int fwhrng_detach(device_t, int); |
| 60 | |
| 61 | static void fwhrng_callout(void *v); |
| 62 | |
| 63 | #define FWHRNG_RETRIES 1000 |
| 64 | #define FWHRNG_MIN_SAMPLES 10 |
| 65 | |
| 66 | CFATTACH_DECL_NEW(fwhrng, sizeof(struct fwhrng_softc), |
| 67 | fwhrng_match, fwhrng_attach, fwhrng_detach, NULL); |
| 68 | |
| 69 | static int |
| 70 | fwhrng_match(device_t parent, cfdata_t match, void *aux) |
| 71 | { |
| 72 | bus_space_tag_t bst; |
| 73 | bus_space_handle_t bsh; |
| 74 | uint8_t id0, id1, data0, data1; |
| 75 | |
| 76 | bst = x86_bus_space_mem; |
| 77 | |
| 78 | /* read chip ID */ |
| 79 | if (bus_space_map(bst, I82802AB_MEMBASE, I82802AB_WINSIZE, 0, &bsh)) |
| 80 | return 0; |
| 81 | |
| 82 | bus_space_write_1(bst, bsh, 0, 0xff); /* reset */ |
| 83 | data0 = bus_space_read_1(bst, bsh, 0); |
| 84 | data1 = bus_space_read_1(bst, bsh, 1); |
| 85 | bus_space_write_1(bst, bsh, 0, 0x90); /* enter read id */ |
| 86 | id0 = bus_space_read_1(bst, bsh, 0); |
| 87 | id1 = bus_space_read_1(bst, bsh, 1); |
| 88 | bus_space_write_1(bst, bsh, 0, 0xff); /* reset */ |
| 89 | |
| 90 | bus_space_unmap(bst, bsh, I82802AB_WINSIZE); |
| 91 | |
| 92 | aprint_debug_dev(parent, "fwh: data %02x,%02x, id %02x,%02x\n" , |
| 93 | data0, data1, id0, id1); |
| 94 | |
| 95 | /* unlikely to have these match if we actually read the ID */ |
| 96 | if ((id0 == data0) && (id1 == data1)) |
| 97 | return 0; |
| 98 | |
| 99 | /* check for chips with RNG */ |
| 100 | if (!(id0 == I82802_MFG)) |
| 101 | return 0; |
| 102 | if (!((id1 == I82802AB_ID) || (id1 == I82802AC_ID))) |
| 103 | return 0; |
| 104 | |
| 105 | /* check for RNG presence */ |
| 106 | if (bus_space_map(bst, I82802AC_REGBASE, I82802AC_WINSIZE, 0, &bsh)) |
| 107 | return 0; |
| 108 | data0 = bus_space_read_1(bst, bsh, I82802_RNG_HSR); |
| 109 | bus_space_unmap(bst, bsh, I82802AC_WINSIZE); |
| 110 | if ((data0 & I82802_RNG_HSR_PRESENT) == I82802_RNG_HSR_PRESENT) |
| 111 | return 1; |
| 112 | |
| 113 | return 0; |
| 114 | } |
| 115 | |
| 116 | static void |
| 117 | fwhrng_attach(device_t parent, device_t self, void *aux) |
| 118 | { |
| 119 | struct fwhrng_softc *sc; |
| 120 | int i, j, count_ff; |
| 121 | uint8_t reg8; |
| 122 | |
| 123 | sc = device_private(self); |
| 124 | sc->sc_dev = self; |
| 125 | |
| 126 | aprint_naive("\n" ); |
| 127 | aprint_normal(": Intel Firmware Hub Random Number Generator\n" ); |
| 128 | |
| 129 | sc->sc_st = x86_bus_space_mem; |
| 130 | |
| 131 | if (bus_space_map(sc->sc_st, I82802AC_REGBASE, I82802AC_WINSIZE, 0, |
| 132 | &sc->sc_sh) != 0) { |
| 133 | aprint_error_dev(self, "unable to map registers\n" ); |
| 134 | return; |
| 135 | } |
| 136 | |
| 137 | /* Enable the RNG. */ |
| 138 | reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh, I82802_RNG_HSR); |
| 139 | bus_space_write_1(sc->sc_st, sc->sc_sh, I82802_RNG_HSR, |
| 140 | reg8 | I82802_RNG_HSR_ENABLE); |
| 141 | reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh, I82802_RNG_HSR); |
| 142 | if ((reg8 & I82802_RNG_HSR_ENABLE) == 0) { |
| 143 | aprint_error_dev(self, "unable to enable\n" ); |
| 144 | bus_space_unmap(sc->sc_st, sc->sc_sh, I82802AC_WINSIZE); |
| 145 | return; |
| 146 | } |
| 147 | |
| 148 | /* Check to see if we can read data from the RNG. */ |
| 149 | count_ff = 0; |
| 150 | for (j = 0; j < FWHRNG_MIN_SAMPLES; ++j) { |
| 151 | for (i = 0; i < FWHRNG_RETRIES; i++) { |
| 152 | reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh, |
| 153 | I82802_RNG_DSR); |
| 154 | if (!(reg8 & I82802_RNG_DSR_VALID)) { |
| 155 | delay(10); |
| 156 | continue; |
| 157 | } |
| 158 | reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh, |
| 159 | I82802_RNG_DR); |
| 160 | break; |
| 161 | } |
| 162 | if (i == FWHRNG_RETRIES) { |
| 163 | bus_space_unmap(sc->sc_st, sc->sc_sh, I82802AC_WINSIZE); |
| 164 | aprint_verbose_dev(sc->sc_dev, |
| 165 | "timeout reading test samples, RNG disabled.\n" ); |
| 166 | return; |
| 167 | } |
| 168 | if (reg8 == 0xff) |
| 169 | ++count_ff; |
| 170 | } |
| 171 | |
| 172 | if (count_ff == FWHRNG_MIN_SAMPLES) { |
| 173 | /* Disable the RNG. */ |
| 174 | reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh, I82802_RNG_HSR); |
| 175 | bus_space_write_1(sc->sc_st, sc->sc_sh, I82802_RNG_HSR, |
| 176 | reg8 & ~I82802_RNG_HSR_ENABLE); |
| 177 | bus_space_unmap(sc->sc_st, sc->sc_sh, I82802AC_WINSIZE); |
| 178 | aprint_error_dev(sc->sc_dev, |
| 179 | "returns constant 0xff stream, RNG disabled.\n" ); |
| 180 | return; |
| 181 | } |
| 182 | |
| 183 | /* |
| 184 | * Should test entropy source to ensure |
| 185 | * that it passes the Statistical Random |
| 186 | * Number Generator Tests in section 4.11.1, |
| 187 | * FIPS PUB 140-1. |
| 188 | * |
| 189 | * http://csrc.nist.gov/fips/fips1401.htm |
| 190 | */ |
| 191 | |
| 192 | aprint_debug_dev(sc->sc_dev, "random number generator enabled\n" ); |
| 193 | |
| 194 | callout_init(&sc->sc_rnd_ch, 0); |
| 195 | /* FWH is polled for entropy, so no estimate is available. */ |
| 196 | rnd_attach_source(&sc->sc_rnd_source, device_xname(sc->sc_dev), |
| 197 | RND_TYPE_RNG, RND_FLAG_COLLECT_VALUE); |
| 198 | sc->sc_rnd_i = sizeof(sc->sc_rnd_ax); |
| 199 | fwhrng_callout(sc); |
| 200 | |
| 201 | return; |
| 202 | } |
| 203 | |
| 204 | static int |
| 205 | fwhrng_detach(device_t self, int flags) |
| 206 | { |
| 207 | struct fwhrng_softc *sc; |
| 208 | uint8_t reg8; |
| 209 | |
| 210 | sc = device_private(self); |
| 211 | |
| 212 | rnd_detach_source(&sc->sc_rnd_source); |
| 213 | |
| 214 | callout_halt(&sc->sc_rnd_ch, NULL); |
| 215 | callout_destroy(&sc->sc_rnd_ch); |
| 216 | |
| 217 | /* Disable the RNG. */ |
| 218 | reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh, I82802_RNG_HSR); |
| 219 | bus_space_write_1(sc->sc_st, sc->sc_sh, I82802_RNG_HSR, |
| 220 | reg8 & ~I82802_RNG_HSR_ENABLE); |
| 221 | |
| 222 | bus_space_unmap(sc->sc_st, sc->sc_sh, I82802AC_WINSIZE); |
| 223 | |
| 224 | return 0; |
| 225 | } |
| 226 | |
| 227 | static void |
| 228 | fwhrng_callout(void *v) |
| 229 | { |
| 230 | struct fwhrng_softc *sc = v; |
| 231 | |
| 232 | if ((bus_space_read_1(sc->sc_st, sc->sc_sh, I82802_RNG_DSR) & |
| 233 | I82802_RNG_DSR_VALID) != 0) { |
| 234 | sc->sc_rnd_ax = (sc->sc_rnd_ax << NBBY) | |
| 235 | bus_space_read_1(sc->sc_st, sc->sc_sh, I82802_RNG_DR); |
| 236 | if (--sc->sc_rnd_i == 0) { |
| 237 | sc->sc_rnd_i = sizeof(sc->sc_rnd_ax); |
| 238 | rnd_add_data(&sc->sc_rnd_source, &sc->sc_rnd_ax, |
| 239 | sizeof(sc->sc_rnd_ax), |
| 240 | sizeof(sc->sc_rnd_ax) * NBBY); |
| 241 | } |
| 242 | } |
| 243 | callout_reset(&sc->sc_rnd_ch, 1, fwhrng_callout, sc); |
| 244 | } |
| 245 | |