drivers/hwmon/hwmon-vid.c

   1 /*
   2     hwmon-vid.c - VID/VRM/VRD voltage conversions
   3
   4     Copyright (c) 2004 Rudolf Marek <r.marek@sh.cvut.cz>
   5
   6     Partly imported from i2c-vid.h of the lm_sensors project
   7     Copyright (c) 2002 Mark D. Studebaker <mdsxyz123@yahoo.com>
   8     With assistance from Trent Piepho <xyzzy@speakeasy.org>
   9
  10     This program is free software; you can redistribute it and/or modify
  11     it under the terms of the GNU General Public License as published by
  12     the Free Software Foundation; either version 2 of the License, or
  13     (at your option) any later version.
  14
  15     This program is distributed in the hope that it will be useful,
  16     but WITHOUT ANY WARRANTY; without even the implied warranty of
  17     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18     GNU General Public License for more details.
  19
  20     You should have received a copy of the GNU General Public License
  21     along with this program; if not, write to the Free Software
  22     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  23 */
  24
  25 #include <linux/config.h>
  26 #include <linux/module.h>
  27 #include <linux/kernel.h>
  28 #include <linux/hwmon-vid.h>
  29
  30 /*
  31     Common code for decoding VID pins.
  32
  33     References:
  34
  35     For VRM 8.4 to 9.1, "VRM x.y DC-DC Converter Design Guidelines",
  36     available at http://developer.intel.com/.
  37
  38     For VRD 10.0 and up, "VRD x.y Design Guide",
  39     available at http://developer.intel.com/.
  40
  41     AMD Opteron processors don't follow the Intel specifications.
  42     I'm going to "make up" 2.4 as the spec number for the Opterons.
  43     No good reason just a mnemonic for the 24x Opteron processor
  44     series.
  45
  46     Opteron VID encoding is:
  47        00000  =  1.550 V
  48        00001  =  1.525 V
  49         . . . .
  50        11110  =  0.800 V
  51        11111  =  0.000 V (off)
  52
  53     The 17 specification is in fact Intel Mobile Voltage Positioning -
  54     (IMVP-II). You can find more information in the datasheet of Max1718
  55     http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2452
  56
  57     The 13 specification corresponds to the Intel Pentium M series. There
  58     doesn't seem to be any named specification for these. The conversion
  59     tables are detailed directly in the various Pentium M datasheets:
  60     http://www.intel.com/design/intarch/pentiumm/docs_pentiumm.htm
  61 */
  62
  63 /* vrm is the VRM/VRD document version multiplied by 10.
  64    val is the 4-, 5- or 6-bit VID code.
  65    Returned value is in mV to avoid floating point in the kernel. */
  66 int vid_from_reg(int val, u8 vrm)
  67 {
  68         int vid;
  69
  70         switch(vrm) {
  71
  72         case 100:               /* VRD 10.0 */
  73                 if((val & 0x1f) == 0x1f)
  74                         return 0;
  75                 if((val & 0x1f) <= 0x09 || val == 0x0a)
  76                         vid = 10875 - (val & 0x1f) * 250;
  77                 else
  78                         vid = 18625 - (val & 0x1f) * 250;
  79                 if(val & 0x20)
  80                         vid -= 125;
  81                 vid /= 10;      /* only return 3 dec. places for now */
  82                 return vid;
  83
  84         case 24:                /* Opteron processor */
  85                 return(val == 0x1f ? 0 : 1550 - val * 25);
  86
  87         case 91:                /* VRM 9.1 */
  88         case 90:                /* VRM 9.0 */
  89                 return(val == 0x1f ? 0 :
  90                                        1850 - val * 25);
  91
  92         case 85:                /* VRM 8.5 */
  93                 return((val & 0x10  ? 25 : 0) +
  94                        ((val & 0x0f) > 0x04 ? 2050 : 1250) -
  95                        ((val & 0x0f) * 50));
  96
  97         case 84:                /* VRM 8.4 */
  98                 val &= 0x0f;
  99                                 /* fall through */
 100         case 82:                /* VRM 8.2 */
 101                 return(val == 0x1f ? 0 :
 102                        val & 0x10  ? 5100 - (val) * 100 :
 103                                      2050 - (val) * 50);
 104         case 17:                /* Intel IMVP-II */
 105                 return(val & 0x10 ? 975 - (val & 0xF) * 25 :
 106                                     1750 - val * 50);
 107         case 13:
 108                 return(1708 - (val & 0x3f) * 16);
 109         default:                /* report 0 for unknown */
 110                 printk(KERN_INFO "hwmon-vid: requested unknown VRM version\n");
 111                 return 0;
 112         }
 113 }
 114
 115
 116 /*
 117     After this point is the code to automatically determine which
 118     VRM/VRD specification should be used depending on the CPU.
 119 */
 120
 121 struct vrm_model {
 122         u8 vendor;
 123         u8 eff_family;
 124         u8 eff_model;
 125         u8 eff_stepping;
 126         u8 vrm_type;
 127 };
 128
 129 #define ANY 0xFF
 130
 131 #ifdef CONFIG_X86
 132
 133 /* the stepping parameter is highest acceptable stepping for current line */
 134
 135 static struct vrm_model vrm_models[] = {
 136         {X86_VENDOR_AMD, 0x6, ANY, ANY, 90},            /* Athlon Duron etc */
 137         {X86_VENDOR_AMD, 0xF, ANY, ANY, 24},            /* Athlon 64, Opteron and above VRM 24 */
 138         {X86_VENDOR_INTEL, 0x6, 0x9, ANY, 13},          /* Pentium M (130 nm) */
 139         {X86_VENDOR_INTEL, 0x6, 0xB, ANY, 85},          /* Tualatin */
 140         {X86_VENDOR_INTEL, 0x6, 0xD, ANY, 13},          /* Pentium M (90 nm) */
 141         {X86_VENDOR_INTEL, 0x6, ANY, ANY, 82},          /* any P6 */
 142         {X86_VENDOR_INTEL, 0x7, ANY, ANY, 0},           /* Itanium */
 143         {X86_VENDOR_INTEL, 0xF, 0x0, ANY, 90},          /* P4 */
 144         {X86_VENDOR_INTEL, 0xF, 0x1, ANY, 90},          /* P4 Willamette */
 145         {X86_VENDOR_INTEL, 0xF, 0x2, ANY, 90},          /* P4 Northwood */
 146         {X86_VENDOR_INTEL, 0xF, ANY, ANY, 100},         /* Prescott and above assume VRD 10 */
 147         {X86_VENDOR_INTEL, 0x10, ANY, ANY, 0},          /* Itanium 2 */
 148         {X86_VENDOR_CENTAUR, 0x6, 0x7, ANY, 85},        /* Eden ESP/Ezra */
 149         {X86_VENDOR_CENTAUR, 0x6, 0x8, 0x7, 85},        /* Ezra T */
 150         {X86_VENDOR_CENTAUR, 0x6, 0x9, 0x7, 85},        /* Nemiah */
 151         {X86_VENDOR_CENTAUR, 0x6, 0x9, ANY, 17},        /* C3-M */
 152         {X86_VENDOR_UNKNOWN, ANY, ANY, ANY, 0}          /* stop here */
 153 };
 154
 155 static u8 find_vrm(u8 eff_family, u8 eff_model, u8 eff_stepping, u8 vendor)
 156 {
 157         int i = 0;
 158
 159         while (vrm_models[i].vendor!=X86_VENDOR_UNKNOWN) {
 160                 if (vrm_models[i].vendor==vendor)
 161                         if ((vrm_models[i].eff_family==eff_family)
 162                          && ((vrm_models[i].eff_model==eff_model) ||
 163                              (vrm_models[i].eff_model==ANY)) &&
 164                              (eff_stepping <= vrm_models[i].eff_stepping))
 165                                 return vrm_models[i].vrm_type;
 166                 i++;
 167         }
 168
 169         return 0;
 170 }
 171
 172 u8 vid_which_vrm(void)
 173 {
 174         struct cpuinfo_x86 *c = cpu_data;
 175         u32 eax;
 176         u8 eff_family, eff_model, eff_stepping, vrm_ret;
 177
 178         if (c->x86 < 6)         /* Any CPU with family lower than 6 */
 179                 return 0;       /* doesn't have VID and/or CPUID */
 180
 181         eax = cpuid_eax(1);
 182         eff_family = ((eax & 0x00000F00)>>8);
 183         eff_model  = ((eax & 0x000000F0)>>4);
 184         eff_stepping = eax & 0xF;
 185         if (eff_family == 0xF) {        /* use extended model & family */
 186                 eff_family += ((eax & 0x00F00000)>>20);
 187                 eff_model += ((eax & 0x000F0000)>>16)<<4;
 188         }
 189         vrm_ret = find_vrm(eff_family, eff_model, eff_stepping, c->x86_vendor);
 190         if (vrm_ret == 0)
 191                 printk(KERN_INFO "hwmon-vid: Unknown VRM version of your "
 192                        "x86 CPU\n");
 193         return vrm_ret;
 194 }
 195
 196 /* and now for something completely different for the non-x86 world */
 197 #else
 198 u8 vid_which_vrm(void)
 199 {
 200         printk(KERN_INFO "hwmon-vid: Unknown VRM version of your CPU\n");
 201         return 0;
 202 }
 203 #endif
 204
 205 EXPORT_SYMBOL(vid_from_reg);
 206 EXPORT_SYMBOL(vid_which_vrm);
 207
 208 MODULE_AUTHOR("Rudolf Marek <r.marek@sh.cvut.cz>");
 209
 210 MODULE_DESCRIPTION("hwmon-vid driver");
 211 MODULE_LICENSE("GPL");