fwhrng.c revision 1.3.2.1
1 /* $NetBSD: fwhrng.c,v 1.3.2.1 2012/04/17 00:07:05 yamt 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 1.3.2.1 2012/04/17 00:07:05 yamt 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/rnd.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 int ret; 75 uint8_t id0, id1, data0, data1; 76 77 ret = 0; 78 79 bst = x86_bus_space_mem; 80 81 /* read chip ID */ 82 if (bus_space_map(bst, I82802AB_MEMBASE, I82802AB_WINSIZE, 0, &bsh)) 83 return 0; 84 85 bus_space_write_1(bst, bsh, 0, 0xff); /* reset */ 86 data0 = bus_space_read_1(bst, bsh, 0); 87 data1 = bus_space_read_1(bst, bsh, 1); 88 bus_space_write_1(bst, bsh, 0, 0x90); /* enter read id */ 89 id0 = bus_space_read_1(bst, bsh, 0); 90 id1 = bus_space_read_1(bst, bsh, 1); 91 bus_space_write_1(bst, bsh, 0, 0xff); /* reset */ 92 93 bus_space_unmap(bst, bsh, I82802AB_WINSIZE); 94 95 aprint_debug_dev(parent, "fwh: data %02x,%02x, id %02x,%02x\n", 96 data0, data1, id0, id1); 97 98 /* unlikely to have these match if we actually read the ID */ 99 if ((id0 == data0) && (id1 == data1)) 100 return 0; 101 102 /* check for chips with RNG */ 103 if (!(id0 == I82802_MFG)) 104 return 0; 105 if (!((id1 == I82802AB_ID) || (id1 == I82802AC_ID))) 106 return 0; 107 108 /* check for RNG presence */ 109 if (bus_space_map(bst, I82802AC_REGBASE, I82802AC_WINSIZE, 0, &bsh)) 110 return 0; 111 data0 = bus_space_read_1(bst, bsh, I82802_RNG_HSR); 112 bus_space_unmap(bst, bsh, I82802AC_WINSIZE); 113 if ((data0 & I82802_RNG_HSR_PRESENT) == I82802_RNG_HSR_PRESENT) 114 return 1; 115 116 return 0; 117 } 118 119 static void 120 fwhrng_attach(device_t parent, device_t self, void *aux) 121 { 122 struct fwhrng_softc *sc; 123 int i, j, count_ff; 124 uint8_t reg8; 125 126 sc = device_private(self); 127 sc->sc_dev = self; 128 129 aprint_naive("\n"); 130 aprint_normal(": Intel Firmware Hub Random Number Generator\n"); 131 132 sc->sc_st = x86_bus_space_mem; 133 134 if (bus_space_map(sc->sc_st, I82802AC_REGBASE, I82802AC_WINSIZE, 0, 135 &sc->sc_sh) != 0) { 136 aprint_error_dev(self, "unable to map registers\n"); 137 return; 138 } 139 140 /* Enable the RNG. */ 141 reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh, I82802_RNG_HSR); 142 bus_space_write_1(sc->sc_st, sc->sc_sh, I82802_RNG_HSR, 143 reg8 | I82802_RNG_HSR_ENABLE); 144 reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh, I82802_RNG_HSR); 145 if ((reg8 & I82802_RNG_HSR_ENABLE) == 0) { 146 aprint_error_dev(self, "unable to enable\n"); 147 bus_space_unmap(sc->sc_st, sc->sc_sh, I82802AC_WINSIZE); 148 return; 149 } 150 151 /* Check to see if we can read data from the RNG. */ 152 count_ff = 0; 153 for (j = 0; j < FWHRNG_MIN_SAMPLES; ++j) { 154 for (i = 0; i < FWHRNG_RETRIES; i++) { 155 reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh, 156 I82802_RNG_DSR); 157 if (!(reg8 & I82802_RNG_DSR_VALID)) { 158 delay(10); 159 continue; 160 } 161 reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh, 162 I82802_RNG_DR); 163 break; 164 } 165 if (i == FWHRNG_RETRIES) { 166 bus_space_unmap(sc->sc_st, sc->sc_sh, I82802AC_WINSIZE); 167 aprint_verbose_dev(sc->sc_dev, 168 "timeout reading test samples, RNG disabled.\n"); 169 return; 170 } 171 if (reg8 == 0xff) 172 ++count_ff; 173 } 174 175 if (count_ff == FWHRNG_MIN_SAMPLES) { 176 /* Disable the RNG. */ 177 reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh, I82802_RNG_HSR); 178 bus_space_write_1(sc->sc_st, sc->sc_sh, I82802_RNG_HSR, 179 reg8 & ~I82802_RNG_HSR_ENABLE); 180 bus_space_unmap(sc->sc_st, sc->sc_sh, I82802AC_WINSIZE); 181 aprint_error_dev(sc->sc_dev, 182 "returns constant 0xff stream, RNG disabled.\n"); 183 return; 184 } 185 186 /* 187 * Should test entropy source to ensure 188 * that it passes the Statistical Random 189 * Number Generator Tests in section 4.11.1, 190 * FIPS PUB 140-1. 191 * 192 * http://csrc.nist.gov/fips/fips1401.htm 193 */ 194 195 aprint_debug_dev(sc->sc_dev, "random number generator enabled\n"); 196 197 callout_init(&sc->sc_rnd_ch, 0); 198 /* FWH is polled for entropy, so no estimate is available. */ 199 rnd_attach_source(&sc->sc_rnd_source, device_xname(sc->sc_dev), 200 RND_TYPE_RNG, RND_FLAG_NO_ESTIMATE); 201 sc->sc_rnd_i = sizeof(sc->sc_rnd_ax); 202 fwhrng_callout(sc); 203 204 return; 205 } 206 207 static int 208 fwhrng_detach(device_t self, int flags) 209 { 210 struct fwhrng_softc *sc; 211 uint8_t reg8; 212 213 sc = device_private(self); 214 215 rnd_detach_source(&sc->sc_rnd_source); 216 217 callout_stop(&sc->sc_rnd_ch); 218 callout_destroy(&sc->sc_rnd_ch); 219 220 /* Disable the RNG. */ 221 reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh, I82802_RNG_HSR); 222 bus_space_write_1(sc->sc_st, sc->sc_sh, I82802_RNG_HSR, 223 reg8 & ~I82802_RNG_HSR_ENABLE); 224 225 bus_space_unmap(sc->sc_st, sc->sc_sh, I82802AC_WINSIZE); 226 227 return 0; 228 } 229 230 static void 231 fwhrng_callout(void *v) 232 { 233 struct fwhrng_softc *sc = v; 234 235 if ((bus_space_read_1(sc->sc_st, sc->sc_sh, I82802_RNG_DSR) & 236 I82802_RNG_DSR_VALID) != 0) { 237 sc->sc_rnd_ax = (sc->sc_rnd_ax << NBBY) | 238 bus_space_read_1(sc->sc_st, sc->sc_sh, I82802_RNG_DR); 239 if (--sc->sc_rnd_i == 0) { 240 sc->sc_rnd_i = sizeof(sc->sc_rnd_ax); 241 rnd_add_data(&sc->sc_rnd_source, &sc->sc_rnd_ax, 242 sizeof(sc->sc_rnd_ax), 243 sizeof(sc->sc_rnd_ax) * NBBY); 244 } 245 } 246 callout_reset(&sc->sc_rnd_ch, 1, fwhrng_callout, sc); 247 } 248
Indexes created Fri Oct 17 23:09:53 GMT 2025