sys/arch/x86/pci/pchb_rnd.c

   1 /*      $NetBSD: pchb_rnd.c,v 1.8 2008/03/04 15:33:06 cube 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: pchb_rnd.c,v 1.8 2008/03/04 15:33:06 cube Exp $");
  33
  34 #include <sys/param.h>
  35 #include <sys/systm.h>
  36 #include <sys/device.h>
  37 #include <sys/time.h>
  38
  39 #include <machine/bus.h>
  40
  41 #include <dev/pci/pcivar.h>
  42 #include <dev/pci/pcireg.h>
  43 #include <dev/pci/pcidevs.h>
  44
  45 #include <arch/x86/pci/i82802reg.h>
  46 #include <arch/x86/pci/pchbvar.h>
  47
  48 static void pchb_rnd_callout(void *v);
  49
  50 #define PCHB_RNG_RETRIES        1000
  51 #define PCHB_RNG_MIN_SAMPLES    10
  52
  53 void
  54 pchb_detach_rnd(struct pchb_softc *sc)
  55 {
  56         uint8_t reg8;
  57
  58         if (!sc->sc_rnd_attached)
  59                 return;
  60
  61         /* pch is polled for entropy, so no estimate is available. */
  62         rnd_detach_source(&sc->sc_rnd_source);
  63
  64         callout_stop(&sc->sc_rnd_ch);
  65         callout_destroy(&sc->sc_rnd_ch);
  66
  67         /* Disable the RNG. */
  68         reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh, I82802_RNG_HWST);
  69         bus_space_write_1(sc->sc_st, sc->sc_sh, I82802_RNG_HWST,
  70             reg8 & ~I82802_RNG_HWST_ENABLE);
  71
  72         bus_space_unmap(sc->sc_st, sc->sc_sh, I82802_IOSIZE);
  73
  74         sc->sc_rnd_attached = false;
  75 }
  76
  77 void
  78 pchb_attach_rnd(struct pchb_softc *sc, struct pci_attach_args *pa)
  79 {
  80         int i, j, count_ff;
  81         uint8_t reg8;
  82
  83         if (PCI_VENDOR(pa->pa_id) != PCI_VENDOR_INTEL)
  84                 return;
  85
  86         switch (PCI_PRODUCT(pa->pa_id)) {
  87 #if defined(__i386__)
  88         /* Old chipsets which only support IA32 CPUs. */
  89         case PCI_PRODUCT_INTEL_82810E_MCH:
  90         case PCI_PRODUCT_INTEL_82810_DC100_MCH:
  91         case PCI_PRODUCT_INTEL_82810_MCH:
  92         case PCI_PRODUCT_INTEL_82815_DC100_HUB:
  93         case PCI_PRODUCT_INTEL_82815_NOAGP_HUB:
  94         case PCI_PRODUCT_INTEL_82815_NOGRAPH_HUB:
  95         case PCI_PRODUCT_INTEL_82815_FULL_HUB:
  96         case PCI_PRODUCT_INTEL_82820_MCH:
  97         case PCI_PRODUCT_INTEL_82840_HB:
  98         case PCI_PRODUCT_INTEL_82845_HB:
  99         case PCI_PRODUCT_INTEL_82850_HB:
 100         case PCI_PRODUCT_INTEL_82860_HB:
 101         case PCI_PRODUCT_INTEL_82865_HB:
 102         case PCI_PRODUCT_INTEL_82875P_HB:
 103 #endif  /* defined((__i386__) */
 104         /* New chipsets which support EM64T CPUs. */
 105         case PCI_PRODUCT_INTEL_82915G_HB:
 106         case PCI_PRODUCT_INTEL_82915GM_HB:
 107         case PCI_PRODUCT_INTEL_82925X_HB:
 108         case PCI_PRODUCT_INTEL_82945P_MCH:
 109         case PCI_PRODUCT_INTEL_82955X_HB:
 110                 break;
 111         default:
 112                 return;
 113         }
 114
 115         sc->sc_st = pa->pa_memt;
 116         if (bus_space_map(sc->sc_st, I82802_IOBASE, I82802_IOSIZE, 0,
 117             &sc->sc_sh) != 0) {
 118                 /*
 119                  * Unable to map control registers, punt,
 120                  * but don't bother issuing a warning.
 121                  */
 122                 return;
 123         }
 124
 125         reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh,
 126             I82802_RNG_HWST);
 127         if ((reg8 & I82802_RNG_HWST_PRESENT) == 0) {
 128                 /*
 129                  * Random number generator is not present.
 130                  */
 131                 bus_space_unmap(sc->sc_st, sc->sc_sh, I82802_IOSIZE);
 132                 return;
 133         }
 134
 135         /* Enable the RNG. */
 136         bus_space_write_1(sc->sc_st, sc->sc_sh,
 137             I82802_RNG_HWST, reg8 | I82802_RNG_HWST_ENABLE);
 138         reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh, I82802_RNG_HWST);
 139         if ((reg8 & I82802_RNG_HWST_ENABLE) == 0) {
 140                 /*
 141                  * Couldn't enable the RNG.
 142                  */
 143                 bus_space_unmap(sc->sc_st, sc->sc_sh, I82802_IOSIZE);
 144                 return;
 145         }
 146
 147         /* Check to see if we can read data from the RNG. */
 148         count_ff = 0;
 149         for (j = 0; j < PCHB_RNG_MIN_SAMPLES; ++j) {
 150                 for (i = 0; i < PCHB_RNG_RETRIES; i++) {
 151                         reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh,
 152                             I82802_RNG_RNGST);
 153                         if (!(reg8 & I82802_RNG_RNGST_DATAV)) {
 154                                 delay(10);
 155                                 continue;
 156                         }
 157                         reg8 = bus_space_read_1(sc->sc_st, sc->sc_sh,
 158                             I82802_RNG_DATA);
 159                         break;
 160                 }
 161                 if (i == PCHB_RNG_RETRIES) {
 162                         bus_space_unmap(sc->sc_st, sc->sc_sh, I82802_IOSIZE);
 163                         aprint_verbose_dev(sc->sc_dev,
 164                             "timeout reading test samples, RNG disabled.\n");
 165                         return;
 166                 }
 167                 if (reg8 == 0xff)
 168                         ++count_ff;
 169         }
 170
 171         if (count_ff == PCHB_RNG_MIN_SAMPLES) {
 172                 bus_space_unmap(sc->sc_st, sc->sc_sh, I82802_IOSIZE);
 173                 aprint_verbose_dev(sc->sc_dev,
 174                     "returns constant 0xff stream, RNG disabled.\n");
 175                 return;
 176         }
 177
 178         /*
 179          * Should test entropy source to ensure
 180          * that it passes the Statistical Random
 181          * Number Generator Tests in section 4.11.1,
 182          * FIPS PUB 140-1.
 183          *
 184          *      http://csrc.nist.gov/fips/fips1401.htm
 185          */
 186
 187         aprint_normal_dev(sc->sc_dev, "random number generator enabled\n");
 188
 189         callout_init(&sc->sc_rnd_ch, 0);
 190         /* pch is polled for entropy, so no estimate is available. */
 191         rnd_attach_source(&sc->sc_rnd_source, device_xname(sc->sc_dev),
 192             RND_TYPE_RNG, RND_FLAG_NO_ESTIMATE);
 193         sc->sc_rnd_i = sizeof(sc->sc_rnd_ax);
 194         pchb_rnd_callout(sc);
 195         sc->sc_rnd_attached = true;
 196 }
 197
 198 static void
 199 pchb_rnd_callout(void *v)
 200 {
 201         struct pchb_softc *sc = v;
 202
 203         if ((bus_space_read_1(sc->sc_st, sc->sc_sh, I82802_RNG_RNGST) &
 204              I82802_RNG_RNGST_DATAV) != 0) {
 205                 sc->sc_rnd_ax = (sc->sc_rnd_ax << NBBY) |
 206                     bus_space_read_1(sc->sc_st, sc->sc_sh, I82802_RNG_DATA);
 207                 if (--sc->sc_rnd_i == 0) {
 208                         sc->sc_rnd_i = sizeof(sc->sc_rnd_ax);
 209                         rnd_add_data(&sc->sc_rnd_source, &sc->sc_rnd_ax,
 210                             sizeof(sc->sc_rnd_ax),
 211                             sizeof(sc->sc_rnd_ax) * NBBY);
 212                 }
 213         }
 214         callout_reset(&sc->sc_rnd_ch, 1, pchb_rnd_callout, sc);
 215 }