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 | |