254 lines
7.0 KiB
C
254 lines
7.0 KiB
C
/* $NetBSD: fwhrng.c,v 1.2 2010/08/23 02:57:19 jakllsch Exp $ */
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/*
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* Copyright (c) 2000 Michael Shalayeff
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR OR HIS RELATIVES BE LIABLE FOR ANY DIRECT,
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* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF MIND, USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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* THE POSSIBILITY OF SUCH DAMAGE.
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*
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* from OpenBSD: pchb.c,v 1.23 2000/10/23 20:07:30 deraadt Exp
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: fwhrng.c,v 1.2 2010/08/23 02:57:19 jakllsch Exp $");
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#include "rnd.h"
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#if NRND == 0
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#error fwhrng requires rnd pseudo-device
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#endif
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/device.h>
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#include <sys/time.h>
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#include <sys/rnd.h>
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#include <machine/bus.h>
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#include <arch/x86/pci/i82802reg.h>
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struct fwhrng_softc {
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device_t sc_dev;
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bus_space_tag_t sc_st;
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bus_space_handle_t sc_sh;
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struct callout sc_rnd_ch;
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rndsource_element_t sc_rnd_source;
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int sc_rnd_i;
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uint32_t sc_rnd_ax;
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};
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static int fwhrng_match(device_t, cfdata_t, void *);
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static void fwhrng_attach(device_t, device_t, void *);
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static int fwhrng_detach(device_t, int);
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static void fwhrng_callout(void *v);
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#define FWHRNG_RETRIES 1000
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#define FWHRNG_MIN_SAMPLES 10
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CFATTACH_DECL_NEW(fwhrng, sizeof(struct fwhrng_softc),
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fwhrng_match, fwhrng_attach, fwhrng_detach, NULL);
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static int
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fwhrng_match(device_t parent, cfdata_t match, void *aux)
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{
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bus_space_tag_t bst;
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bus_space_handle_t bsh;
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int ret;
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uint8_t id0, id1, data0, data1;
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ret = 0;
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bst = x86_bus_space_mem;
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/* read chip ID */
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if (bus_space_map(bst, I82802AB_MEMBASE, I82802AB_WINSIZE, 0, &bsh))
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return 0;
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bus_space_write_1(bst, bsh, 0, 0xff); /* reset */
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data0 = bus_space_read_1(bst, bsh, 0);
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data1 = bus_space_read_1(bst, bsh, 1);
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bus_space_write_1(bst, bsh, 0, 0x90); /* enter read id */
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id0 = bus_space_read_1(bst, bsh, 0);
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id1 = bus_space_read_1(bst, bsh, 1);
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bus_space_write_1(bst, bsh, 0, 0xff); /* reset */
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bus_space_unmap(bst, bsh, I82802AB_WINSIZE);
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aprint_debug_dev(parent, "fwh: data %02x,%02x, id %02x,%02x\n",
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data0, data1, id0, id1);
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/* unlikely to have these match if we actually read the ID */
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if ((id0 == data0) && (id1 == data1))
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return 0;
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/* check for chips with RNG */
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if (!(id0 == I82802_MFG))
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return 0;
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if (!((id1 == I82802AB_ID) || (id1 == I82802AC_ID)))
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return 0;
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/* check for RNG presence */
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if (bus_space_map(bst, I82802AC_REGBASE, I82802AC_WINSIZE, 0, &bsh))
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return 0;
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data0 = bus_space_read_1(bst, bsh, I82802_RNG_HSR);
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bus_space_unmap(bst, bsh, I82802AC_WINSIZE);
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if ((data0 & I82802_RNG_HSR_PRESENT) == I82802_RNG_HSR_PRESENT)
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return 1;
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return 0;
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}
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static void
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fwhrng_attach(device_t parent, device_t self, void *aux)
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{
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struct fwhrng_softc *sc;
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int i, j, count_ff;
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uint8_t reg8;
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sc = device_private(self);
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sc->sc_dev = self;
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aprint_naive("\n");
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aprint_normal(": Intel Firmware Hub Random Number Generator\n");
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sc->sc_st = x86_bus_space_mem;
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if (bus_space_map(sc->sc_st, I82802AC_REGBASE, I82802AC_WINSIZE, 0,
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&sc->sc_sh) != 0) {
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aprint_error_dev(self, "unable to map registers\n");
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return;
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}
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/* Enable the RNG. */
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reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh, I82802_RNG_HSR);
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bus_space_write_1(sc->sc_st, sc->sc_sh, I82802_RNG_HSR,
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reg8 | I82802_RNG_HSR_ENABLE);
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reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh, I82802_RNG_HSR);
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if ((reg8 & I82802_RNG_HSR_ENABLE) == 0) {
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aprint_error_dev(self, "unable to enable\n");
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bus_space_unmap(sc->sc_st, sc->sc_sh, I82802AC_WINSIZE);
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return;
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}
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/* Check to see if we can read data from the RNG. */
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count_ff = 0;
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for (j = 0; j < FWHRNG_MIN_SAMPLES; ++j) {
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for (i = 0; i < FWHRNG_RETRIES; i++) {
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reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh,
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I82802_RNG_DSR);
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if (!(reg8 & I82802_RNG_DSR_VALID)) {
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delay(10);
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continue;
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}
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reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh,
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I82802_RNG_DR);
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break;
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}
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if (i == FWHRNG_RETRIES) {
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bus_space_unmap(sc->sc_st, sc->sc_sh, I82802AC_WINSIZE);
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aprint_verbose_dev(sc->sc_dev,
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"timeout reading test samples, RNG disabled.\n");
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return;
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}
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if (reg8 == 0xff)
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++count_ff;
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}
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if (count_ff == FWHRNG_MIN_SAMPLES) {
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/* Disable the RNG. */
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reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh, I82802_RNG_HSR);
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bus_space_write_1(sc->sc_st, sc->sc_sh, I82802_RNG_HSR,
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reg8 & ~I82802_RNG_HSR_ENABLE);
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bus_space_unmap(sc->sc_st, sc->sc_sh, I82802AC_WINSIZE);
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aprint_error_dev(sc->sc_dev,
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"returns constant 0xff stream, RNG disabled.\n");
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return;
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}
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/*
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* Should test entropy source to ensure
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* that it passes the Statistical Random
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* Number Generator Tests in section 4.11.1,
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* FIPS PUB 140-1.
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*
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* http://csrc.nist.gov/fips/fips1401.htm
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*/
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aprint_debug_dev(sc->sc_dev, "random number generator enabled\n");
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callout_init(&sc->sc_rnd_ch, 0);
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/* FWH is polled for entropy, so no estimate is available. */
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rnd_attach_source(&sc->sc_rnd_source, device_xname(sc->sc_dev),
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RND_TYPE_RNG, RND_FLAG_NO_ESTIMATE);
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sc->sc_rnd_i = sizeof(sc->sc_rnd_ax);
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fwhrng_callout(sc);
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return;
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}
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static int
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fwhrng_detach(device_t self, int flags)
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{
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struct fwhrng_softc *sc;
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uint8_t reg8;
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sc = device_private(self);
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rnd_detach_source(&sc->sc_rnd_source);
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callout_stop(&sc->sc_rnd_ch);
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callout_destroy(&sc->sc_rnd_ch);
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/* Disable the RNG. */
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reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh, I82802_RNG_HSR);
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bus_space_write_1(sc->sc_st, sc->sc_sh, I82802_RNG_HSR,
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reg8 & ~I82802_RNG_HSR_ENABLE);
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bus_space_unmap(sc->sc_st, sc->sc_sh, I82802AC_WINSIZE);
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return 0;
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}
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static void
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fwhrng_callout(void *v)
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{
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struct fwhrng_softc *sc = v;
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if ((bus_space_read_1(sc->sc_st, sc->sc_sh, I82802_RNG_DSR) &
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I82802_RNG_DSR_VALID) != 0) {
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sc->sc_rnd_ax = (sc->sc_rnd_ax << NBBY) |
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bus_space_read_1(sc->sc_st, sc->sc_sh, I82802_RNG_DR);
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if (--sc->sc_rnd_i == 0) {
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sc->sc_rnd_i = sizeof(sc->sc_rnd_ax);
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rnd_add_data(&sc->sc_rnd_source, &sc->sc_rnd_ax,
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sizeof(sc->sc_rnd_ax),
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sizeof(sc->sc_rnd_ax) * NBBY);
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}
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}
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callout_reset(&sc->sc_rnd_ch, 1, fwhrng_callout, sc);
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}
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