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
Indexes created Sun Sep 21 14:09:52 GMT 2025