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 */
  58
  59 /* vrm is the VRM/VRD document version multiplied by 10.
  60    val is the 4-, 5- or 6-bit VID code.
  61    Returned value is in mV to avoid floating point in the kernel. */
  62 int vid_from_reg(int val, u8 vrm)
  63 {
  64         int vid;
  65
  66         switch(vrm) {
  67
  68         case 100:               /* VRD 10.0 */
  69                 if((val & 0x1f) == 0x1f)
  70                         return 0;
  71                 if((val & 0x1f) <= 0x09 || val == 0x0a)
  72                         vid = 10875 - (val & 0x1f) * 250;
  73                 else
  74                         vid = 18625 - (val & 0x1f) * 250;
  75                 if(val & 0x20)
  76                         vid -= 125;
  77                 vid /= 10;      /* only return 3 dec. places for now */
  78                 return vid;
  79
  80         case 24:                /* Opteron processor */
  81                 return(val == 0x1f ? 0 : 1550 - val * 25);
  82
  83         case 91:                /* VRM 9.1 */
  84         case 90:                /* VRM 9.0 */
  85                 return(val == 0x1f ? 0 :
  86                                        1850 - val * 25);
  87
  88         case 85:                /* VRM 8.5 */
  89                 return((val & 0x10  ? 25 : 0) +
  90                        ((val & 0x0f) > 0x04 ? 2050 : 1250) -
  91                        ((val & 0x0f) * 50));
  92
  93         case 84:                /* VRM 8.4 */
  94                 val &= 0x0f;
  95                                 /* fall through */
  96         case 82:                /* VRM 8.2 */
  97                 return(val == 0x1f ? 0 :
  98                        val & 0x10  ? 5100 - (val) * 100 :
  99                                      2050 - (val) * 50);
 100         case 17:                /* Intel IMVP-II */
 101                 return(val & 0x10 ? 975 - (val & 0xF) * 25 :
 102                                     1750 - val * 50);
 103         default:                /* report 0 for unknown */
 104                 printk(KERN_INFO "hwmon-vid: requested unknown VRM version\n");
 105                 return 0;
 106         }
 107 }
 108
 109
 110 /*
 111     After this point is the code to automatically determine which
 112     VRM/VRD specification should be used depending on the CPU.
 113 */
 114
 115 struct vrm_model {
 116         u8 vendor;
 117         u8 eff_family;
 118         u8 eff_model;
 119         u8 eff_stepping;
 120         u8 vrm_type;
 121 };
 122
 123 #define ANY 0xFF
 124
 125 #ifdef CONFIG_X86
 126
 127 /* the stepping parameter is highest acceptable stepping for current line */
 128
 129 static struct vrm_model vrm_models[] = {
 130         {X86_VENDOR_AMD, 0x6, ANY, ANY, 90},            /* Athlon Duron etc */
 131         {X86_VENDOR_AMD, 0xF, ANY, ANY, 24},            /* Athlon 64, Opteron and above VRM 24 */
 132         {X86_VENDOR_INTEL, 0x6, 0x9, ANY, 85},          /* 0.13um too */
 133         {X86_VENDOR_INTEL, 0x6, 0xB, ANY, 85},          /* Tualatin */
 134         {X86_VENDOR_INTEL, 0x6, ANY, ANY, 82},          /* any P6 */
 135         {X86_VENDOR_INTEL, 0x7, ANY, ANY, 0},           /* Itanium */
 136         {X86_VENDOR_INTEL, 0xF, 0x0, ANY, 90},          /* P4 */
 137         {X86_VENDOR_INTEL, 0xF, 0x1, ANY, 90},          /* P4 Willamette */
 138         {X86_VENDOR_INTEL, 0xF, 0x2, ANY, 90},          /* P4 Northwood */
 139         {X86_VENDOR_INTEL, 0xF, ANY, ANY, 100},         /* Prescott and above assume VRD 10 */
 140         {X86_VENDOR_INTEL, 0x10, ANY, ANY, 0},          /* Itanium 2 */
 141         {X86_VENDOR_CENTAUR, 0x6, 0x7, ANY, 85},        /* Eden ESP/Ezra */
 142         {X86_VENDOR_CENTAUR, 0x6, 0x8, 0x7, 85},        /* Ezra T */
 143         {X86_VENDOR_CENTAUR, 0x6, 0x9, 0x7, 85},        /* Nemiah */
 144         {X86_VENDOR_CENTAUR, 0x6, 0x9, ANY, 17},        /* C3-M */
 145         {X86_VENDOR_UNKNOWN, ANY, ANY, ANY, 0}          /* stop here */
 146 };
 147
 148 static u8 find_vrm(u8 eff_family, u8 eff_model, u8 eff_stepping, u8 vendor)
 149 {
 150         int i = 0;
 151
 152         while (vrm_models[i].vendor!=X86_VENDOR_UNKNOWN) {
 153                 if (vrm_models[i].vendor==vendor)
 154                         if ((vrm_models[i].eff_family==eff_family)
 155                          && ((vrm_models[i].eff_model==eff_model) ||
 156                              (vrm_models[i].eff_model==ANY)) &&
 157                              (eff_stepping <= vrm_models[i].eff_stepping))
 158                                 return vrm_models[i].vrm_type;
 159                 i++;
 160         }
 161
 162         return 0;
 163 }
 164
 165 u8 vid_which_vrm(void)
 166 {
 167         struct cpuinfo_x86 *c = cpu_data;
 168         u32 eax;
 169         u8 eff_family, eff_model, eff_stepping, vrm_ret;
 170
 171         if (c->x86 < 6)         /* Any CPU with family lower than 6 */
 172                 return 0;       /* doesn't have VID and/or CPUID */
 173
 174         eax = cpuid_eax(1);
 175         eff_family = ((eax & 0x00000F00)>>8);
 176         eff_model  = ((eax & 0x000000F0)>>4);
 177         eff_stepping = eax & 0xF;
 178         if (eff_family == 0xF) {        /* use extended model & family */
 179                 eff_family += ((eax & 0x00F00000)>>20);
 180                 eff_model += ((eax & 0x000F0000)>>16)<<4;
 181         }
 182         vrm_ret = find_vrm(eff_family, eff_model, eff_stepping, c->x86_vendor);
 183         if (vrm_ret == 0)
 184                 printk(KERN_INFO "hwmon-vid: Unknown VRM version of your "
 185                        "x86 CPU\n");
 186         return vrm_ret;
 187 }
 188
 189 /* and now for something completely different for the non-x86 world */
 190 #else
 191 u8 vid_which_vrm(void)
 192 {
 193         printk(KERN_INFO "hwmon-vid: Unknown VRM version of your CPU\n");
 194         return 0;
 195 }
 196 #endif
 197
 198 EXPORT_SYMBOL(vid_from_reg);
 199 EXPORT_SYMBOL(vid_which_vrm);
 200
 201 MODULE_AUTHOR("Rudolf Marek <r.marek@sh.cvut.cz>");
 202
 203 MODULE_DESCRIPTION("hwmon-vid driver");
 204 MODULE_LICENSE("GPL");