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
  54 /* vrm is the VRM/VRD document version multiplied by 10.
  55    val is the 4-, 5- or 6-bit VID code.
  56    Returned value is in mV to avoid floating point in the kernel. */
  57 int vid_from_reg(int val, int vrm)
  58 {
  59         int vid;
  60
  61         switch(vrm) {
  62
  63         case  0:
  64                 return 0;
  65
  66         case 100:               /* VRD 10.0 */
  67                 if((val & 0x1f) == 0x1f)
  68                         return 0;
  69                 if((val & 0x1f) <= 0x09 || val == 0x0a)
  70                         vid = 10875 - (val & 0x1f) * 250;
  71                 else
  72                         vid = 18625 - (val & 0x1f) * 250;
  73                 if(val & 0x20)
  74                         vid -= 125;
  75                 vid /= 10;      /* only return 3 dec. places for now */
  76                 return vid;
  77
  78         case 24:                /* Opteron processor */
  79                 return(val == 0x1f ? 0 : 1550 - val * 25);
  80
  81         case 91:                /* VRM 9.1 */
  82         case 90:                /* VRM 9.0 */
  83                 return(val == 0x1f ? 0 :
  84                                        1850 - val * 25);
  85
  86         case 85:                /* VRM 8.5 */
  87                 return((val & 0x10  ? 25 : 0) +
  88                        ((val & 0x0f) > 0x04 ? 2050 : 1250) -
  89                        ((val & 0x0f) * 50));
  90
  91         case 84:                /* VRM 8.4 */
  92                 val &= 0x0f;
  93                                 /* fall through */
  94         default:                /* VRM 8.2 */
  95                 return(val == 0x1f ? 0 :
  96                        val & 0x10  ? 5100 - (val) * 100 :
  97                                      2050 - (val) * 50);
  98         }
  99 }
 100
 101
 102 /*
 103     After this point is the code to automatically determine which
 104     VRM/VRD specification should be used depending on the CPU.
 105 */
 106
 107 struct vrm_model {
 108         u8 vendor;
 109         u8 eff_family;
 110         u8 eff_model;
 111         int vrm_type;
 112 };
 113
 114 #define ANY 0xFF
 115
 116 #ifdef CONFIG_X86
 117
 118 static struct vrm_model vrm_models[] = {
 119         {X86_VENDOR_AMD, 0x6, ANY, 90},         /* Athlon Duron etc */
 120         {X86_VENDOR_AMD, 0xF, ANY, 24},         /* Athlon 64, Opteron */
 121         {X86_VENDOR_INTEL, 0x6, 0x9, 85},       /* 0.13um too */
 122         {X86_VENDOR_INTEL, 0x6, 0xB, 85},       /* Tualatin */
 123         {X86_VENDOR_INTEL, 0x6, ANY, 82},       /* any P6 */
 124         {X86_VENDOR_INTEL, 0x7, ANY, 0},        /* Itanium */
 125         {X86_VENDOR_INTEL, 0xF, 0x0, 90},       /* P4 */
 126         {X86_VENDOR_INTEL, 0xF, 0x1, 90},       /* P4 Willamette */
 127         {X86_VENDOR_INTEL, 0xF, 0x2, 90},       /* P4 Northwood */
 128         {X86_VENDOR_INTEL, 0xF, 0x3, 100},      /* P4 Prescott */
 129         {X86_VENDOR_INTEL, 0xF, 0x4, 100},      /* P4 Prescott */
 130         {X86_VENDOR_INTEL, 0x10,ANY, 0},        /* Itanium 2 */
 131         {X86_VENDOR_UNKNOWN, ANY, ANY, 0}       /* stop here */
 132 };
 133
 134 static int find_vrm(u8 eff_family, u8 eff_model, u8 vendor)
 135 {
 136         int i = 0;
 137
 138         while (vrm_models[i].vendor!=X86_VENDOR_UNKNOWN) {
 139                 if (vrm_models[i].vendor==vendor)
 140                         if ((vrm_models[i].eff_family==eff_family)
 141                          && ((vrm_models[i].eff_model==eff_model) ||
 142                              (vrm_models[i].eff_model==ANY)))
 143                                 return vrm_models[i].vrm_type;
 144                 i++;
 145         }
 146
 147         return 0;
 148 }
 149
 150 int vid_which_vrm(void)
 151 {
 152         struct cpuinfo_x86 *c = cpu_data;
 153         u32 eax;
 154         u8 eff_family, eff_model;
 155         int vrm_ret;
 156
 157         if (c->x86 < 6)         /* Any CPU with family lower than 6 */
 158                 return 0;       /* doesn't have VID and/or CPUID */
 159
 160         eax = cpuid_eax(1);
 161         eff_family = ((eax & 0x00000F00)>>8);
 162         eff_model  = ((eax & 0x000000F0)>>4);
 163         if (eff_family == 0xF) {        /* use extended model & family */
 164                 eff_family += ((eax & 0x00F00000)>>20);
 165                 eff_model += ((eax & 0x000F0000)>>16)<<4;
 166         }
 167         vrm_ret = find_vrm(eff_family,eff_model,c->x86_vendor);
 168         if (vrm_ret == 0)
 169                 printk(KERN_INFO "hwmon-vid: Unknown VRM version of your "
 170                        "x86 CPU\n");
 171         return vrm_ret;
 172 }
 173
 174 /* and now something completely different for the non-x86 world */
 175 #else
 176 int vid_which_vrm(void)
 177 {
 178         printk(KERN_INFO "hwmon-vid: Unknown VRM version of your CPU\n");
 179         return 0;
 180 }
 181 #endif
 182
 183 EXPORT_SYMBOL(vid_from_reg);
 184 EXPORT_SYMBOL(vid_which_vrm);
 185
 186 MODULE_AUTHOR("Rudolf Marek <r.marek@sh.cvut.cz>");
 187
 188 MODULE_DESCRIPTION("hwmon-vid driver");
 189 MODULE_LICENSE("GPL");