drivers/hwmon/hwmon-vid.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * hwmon-vid.c - VID/VRM/VRD voltage conversions
   4  *
   5  * Copyright (c) 2004 Rudolf Marek <r.marek@assembler.cz>
   6  *
   7  * Partly imported from i2c-vid.h of the lm_sensors project
   8  * Copyright (c) 2002 Mark D. Studebaker <mdsxyz123@yahoo.com>
   9  * With assistance from Trent Piepho <xyzzy@speakeasy.org>
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/module.h>
  15 #include <linux/kernel.h>
  16 #include <linux/hwmon-vid.h>
  17
  18 /*
  19  * Common code for decoding VID pins.
  20  *
  21  * References:
  22  *
  23  * For VRM 8.4 to 9.1, "VRM x.y DC-DC Converter Design Guidelines",
  24  * available at http://developer.intel.com/.
  25  *
  26  * For VRD 10.0 and up, "VRD x.y Design Guide",
  27  * available at http://developer.intel.com/.
  28  *
  29  * AMD Athlon 64 and AMD Opteron Processors, AMD Publication 26094,
  30  * http://support.amd.com/us/Processor_TechDocs/26094.PDF
  31  * Table 74. VID Code Voltages
  32  * This corresponds to an arbitrary VRM code of 24 in the functions below.
  33  * These CPU models (K8 revision <= E) have 5 VID pins. See also:
  34  * Revision Guide for AMD Athlon 64 and AMD Opteron Processors, AMD Publication 25759,
  35  * http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/25759.pdf
  36  *
  37  * AMD NPT Family 0Fh Processors, AMD Publication 32559,
  38  * http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/32559.pdf
  39  * Table 71. VID Code Voltages
  40  * This corresponds to an arbitrary VRM code of 25 in the functions below.
  41  * These CPU models (K8 revision >= F) have 6 VID pins. See also:
  42  * Revision Guide for AMD NPT Family 0Fh Processors, AMD Publication 33610,
  43  * http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/33610.pdf
  44  *
  45  * The 17 specification is in fact Intel Mobile Voltage Positioning -
  46  * (IMVP-II). You can find more information in the datasheet of Max1718
  47  * http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2452
  48  *
  49  * The 13 specification corresponds to the Intel Pentium M series. There
  50  * doesn't seem to be any named specification for these. The conversion
  51  * tables are detailed directly in the various Pentium M datasheets:
  52  * https://www.intel.com/design/intarch/pentiumm/docs_pentiumm.htm
  53  *
  54  * The 14 specification corresponds to Intel Core series. There
  55  * doesn't seem to be any named specification for these. The conversion
  56  * tables are detailed directly in the various Pentium Core datasheets:
  57  * https://www.intel.com/design/mobile/datashts/309221.htm
  58  *
  59  * The 110 (VRM 11) specification corresponds to Intel Conroe based series.
  60  * https://www.intel.com/design/processor/applnots/313214.htm
  61  */
  62
  63 /*
  64  * vrm is the VRM/VRD document version multiplied by 10.
  65  * val is the 4-bit or more VID code.
  66  * Returned value is in mV to avoid floating point in the kernel.
  67  * Some VID have some bits in uV scale, this is rounded to mV.
  68  */
  69 int vid_from_reg(int val, u8 vrm)
  70 {
  71         int vid;
  72
  73         switch (vrm) {
  74
  75         case 100:               /* VRD 10.0 */
  76                 /* compute in uV, round to mV */
  77                 val &= 0x3f;
  78                 if ((val & 0x1f) == 0x1f)
  79                         return 0;
  80                 if ((val & 0x1f) <= 0x09 || val == 0x0a)
  81                         vid = 1087500 - (val & 0x1f) * 25000;
  82                 else
  83                         vid = 1862500 - (val & 0x1f) * 25000;
  84                 if (val & 0x20)
  85                         vid -= 12500;
  86                 return (vid + 500) / 1000;
  87
  88         case 110:               /* Intel Conroe */
  89                                 /* compute in uV, round to mV */
  90                 val &= 0xff;
  91                 if (val < 0x02 || val > 0xb2)
  92                         return 0;
  93                 return (1600000 - (val - 2) * 6250 + 500) / 1000;
  94
  95         case 24:                /* Athlon64 & Opteron */
  96                 val &= 0x1f;
  97                 if (val == 0x1f)
  98                         return 0;
  99                 fallthrough;
 100         case 25:                /* AMD NPT 0Fh */
 101                 val &= 0x3f;
 102                 return (val < 32) ? 1550 - 25 * val
 103                         : 775 - (25 * (val - 31)) / 2;
 104
 105         case 26:                /* AMD family 10h to 15h, serial VID */
 106                 val &= 0x7f;
 107                 if (val >= 0x7c)
 108                         return 0;
 109                 return DIV_ROUND_CLOSEST(15500 - 125 * val, 10);
 110
 111         case 91:                /* VRM 9.1 */
 112         case 90:                /* VRM 9.0 */
 113                 val &= 0x1f;
 114                 return val == 0x1f ? 0 :
 115                                      1850 - val * 25;
 116
 117         case 85:                /* VRM 8.5 */
 118                 val &= 0x1f;
 119                 return (val & 0x10  ? 25 : 0) +
 120                        ((val & 0x0f) > 0x04 ? 2050 : 1250) -
 121                        ((val & 0x0f) * 50);
 122
 123         case 84:                /* VRM 8.4 */
 124                 val &= 0x0f;
 125                 fallthrough;
 126         case 82:                /* VRM 8.2 */
 127                 val &= 0x1f;
 128                 return val == 0x1f ? 0 :
 129                        val & 0x10  ? 5100 - (val) * 100 :
 130                                      2050 - (val) * 50;
 131         case 17:                /* Intel IMVP-II */
 132                 val &= 0x1f;
 133                 return val & 0x10 ? 975 - (val & 0xF) * 25 :
 134                                     1750 - val * 50;
 135         case 13:
 136         case 131:
 137                 val &= 0x3f;
 138                 /* Exception for Eden ULV 500 MHz */
 139                 if (vrm == 131 && val == 0x3f)
 140                         val++;
 141                 return 1708 - val * 16;
 142         case 14:                /* Intel Core */
 143                                 /* compute in uV, round to mV */
 144                 val &= 0x7f;
 145                 return val > 0x77 ? 0 : (1500000 - (val * 12500) + 500) / 1000;
 146         default:                /* report 0 for unknown */
 147                 if (vrm)
 148                         pr_warn("Requested unsupported VRM version (%u)\n",
 149                                 (unsigned int)vrm);
 150                 return 0;
 151         }
 152 }
 153 EXPORT_SYMBOL(vid_from_reg);
 154
 155 /*
 156  * After this point is the code to automatically determine which
 157  * VRM/VRD specification should be used depending on the CPU.
 158  */
 159
 160 struct vrm_model {
 161         u8 vendor;
 162         u8 family;
 163         u8 model_from;
 164         u8 model_to;
 165         u8 stepping_to;
 166         u8 vrm_type;
 167 };
 168
 169 #define ANY 0xFF
 170
 171 #ifdef CONFIG_X86
 172
 173 /*
 174  * The stepping_to parameter is highest acceptable stepping for current line.
 175  * The model match must be exact for 4-bit values. For model values 0x10
 176  * and above (extended model), all models below the parameter will match.
 177  */
 178
 179 static struct vrm_model vrm_models[] = {
 180         {X86_VENDOR_AMD, 0x6, 0x0, ANY, ANY, 90},       /* Athlon Duron etc */
 181         {X86_VENDOR_AMD, 0xF, 0x0, 0x3F, ANY, 24},      /* Athlon 64, Opteron */
 182         /*
 183          * In theory, all NPT family 0Fh processors have 6 VID pins and should
 184          * thus use vrm 25, however in practice not all mainboards route the
 185          * 6th VID pin because it is never needed. So we use the 5 VID pin
 186          * variant (vrm 24) for the models which exist today.
 187          */
 188         {X86_VENDOR_AMD, 0xF, 0x40, 0x7F, ANY, 24},     /* NPT family 0Fh */
 189         {X86_VENDOR_AMD, 0xF, 0x80, ANY, ANY, 25},      /* future fam. 0Fh */
 190         {X86_VENDOR_AMD, 0x10, 0x0, ANY, ANY, 25},      /* NPT family 10h */
 191         {X86_VENDOR_AMD, 0x11, 0x0, ANY, ANY, 26},      /* family 11h */
 192         {X86_VENDOR_AMD, 0x12, 0x0, ANY, ANY, 26},      /* family 12h */
 193         {X86_VENDOR_AMD, 0x14, 0x0, ANY, ANY, 26},      /* family 14h */
 194         {X86_VENDOR_AMD, 0x15, 0x0, ANY, ANY, 26},      /* family 15h */
 195
 196         {X86_VENDOR_INTEL, 0x6, 0x0, 0x6, ANY, 82},     /* Pentium Pro,
 197                                                          * Pentium II, Xeon,
 198                                                          * Mobile Pentium,
 199                                                          * Celeron */
 200         {X86_VENDOR_INTEL, 0x6, 0x7, 0x7, ANY, 84},     /* Pentium III, Xeon */
 201         {X86_VENDOR_INTEL, 0x6, 0x8, 0x8, ANY, 82},     /* Pentium III, Xeon */
 202         {X86_VENDOR_INTEL, 0x6, 0x9, 0x9, ANY, 13},     /* Pentium M (130 nm) */
 203         {X86_VENDOR_INTEL, 0x6, 0xA, 0xA, ANY, 82},     /* Pentium III Xeon */
 204         {X86_VENDOR_INTEL, 0x6, 0xB, 0xB, ANY, 85},     /* Tualatin */
 205         {X86_VENDOR_INTEL, 0x6, 0xD, 0xD, ANY, 13},     /* Pentium M (90 nm) */
 206         {X86_VENDOR_INTEL, 0x6, 0xE, 0xE, ANY, 14},     /* Intel Core (65 nm) */
 207         {X86_VENDOR_INTEL, 0x6, 0xF, ANY, ANY, 110},    /* Intel Conroe and
 208                                                          * later */
 209         {X86_VENDOR_INTEL, 0xF, 0x0, 0x0, ANY, 90},     /* P4 */
 210         {X86_VENDOR_INTEL, 0xF, 0x1, 0x1, ANY, 90},     /* P4 Willamette */
 211         {X86_VENDOR_INTEL, 0xF, 0x2, 0x2, ANY, 90},     /* P4 Northwood */
 212         {X86_VENDOR_INTEL, 0xF, 0x3, ANY, ANY, 100},    /* Prescott and above
 213                                                          * assume VRD 10 */
 214
 215         {X86_VENDOR_CENTAUR, 0x6, 0x7, 0x7, ANY, 85},   /* Eden ESP/Ezra */
 216         {X86_VENDOR_CENTAUR, 0x6, 0x8, 0x8, 0x7, 85},   /* Ezra T */
 217         {X86_VENDOR_CENTAUR, 0x6, 0x9, 0x9, 0x7, 85},   /* Nehemiah */
 218         {X86_VENDOR_CENTAUR, 0x6, 0x9, 0x9, ANY, 17},   /* C3-M, Eden-N */
 219         {X86_VENDOR_CENTAUR, 0x6, 0xA, 0xA, 0x7, 0},    /* No information */
 220         {X86_VENDOR_CENTAUR, 0x6, 0xA, 0xA, ANY, 13},   /* C7-M, C7,
 221                                                          * Eden (Esther) */
 222         {X86_VENDOR_CENTAUR, 0x6, 0xD, 0xD, ANY, 134},  /* C7-D, C7-M, C7,
 223                                                          * Eden (Esther) */
 224 };
 225
 226 /*
 227  * Special case for VIA model D: there are two different possible
 228  * VID tables, so we have to figure out first, which one must be
 229  * used. This resolves temporary drm value 134 to 14 (Intel Core
 230  * 7-bit VID), 13 (Pentium M 6-bit VID) or 131 (Pentium M 6-bit VID
 231  * + quirk for Eden ULV 500 MHz).
 232  * Note: something similar might be needed for model A, I'm not sure.
 233  */
 234 static u8 get_via_model_d_vrm(void)
 235 {
 236         unsigned int vid, brand, __maybe_unused dummy;
 237         static const char *brands[4] = {
 238                 "C7-M", "C7", "Eden", "C7-D"
 239         };
 240
 241         rdmsr(0x198, dummy, vid);
 242         vid &= 0xff;
 243
 244         rdmsr(0x1154, brand, dummy);
 245         brand = ((brand >> 4) ^ (brand >> 2)) & 0x03;
 246
 247         if (vid > 0x3f) {
 248                 pr_info("Using %d-bit VID table for VIA %s CPU\n",
 249                         7, brands[brand]);
 250                 return 14;
 251         } else {
 252                 pr_info("Using %d-bit VID table for VIA %s CPU\n",
 253                         6, brands[brand]);
 254                 /* Enable quirk for Eden */
 255                 return brand == 2 ? 131 : 13;
 256         }
 257 }
 258
 259 static u8 find_vrm(u8 family, u8 model, u8 stepping, u8 vendor)
 260 {
 261         int i;
 262
 263         for (i = 0; i < ARRAY_SIZE(vrm_models); i++) {
 264                 if (vendor == vrm_models[i].vendor &&
 265                     family == vrm_models[i].family &&
 266                     model >= vrm_models[i].model_from &&
 267                     model <= vrm_models[i].model_to &&
 268                     stepping <= vrm_models[i].stepping_to)
 269                         return vrm_models[i].vrm_type;
 270         }
 271
 272         return 0;
 273 }
 274
 275 u8 vid_which_vrm(void)
 276 {
 277         struct cpuinfo_x86 *c = &cpu_data(0);
 278         u8 vrm_ret;
 279
 280         if (c->x86 < 6)         /* Any CPU with family lower than 6 */
 281                 return 0;       /* doesn't have VID */
 282
 283         vrm_ret = find_vrm(c->x86, c->x86_model, c->x86_stepping, c->x86_vendor);
 284         if (vrm_ret == 134)
 285                 vrm_ret = get_via_model_d_vrm();
 286         if (vrm_ret == 0)
 287                 pr_info("Unknown VRM version of your x86 CPU\n");
 288         return vrm_ret;
 289 }
 290
 291 /* and now for something completely different for the non-x86 world */
 292 #else
 293 u8 vid_which_vrm(void)
 294 {
 295         pr_info("Unknown VRM version of your CPU\n");
 296         return 0;
 297 }
 298 #endif
 299 EXPORT_SYMBOL(vid_which_vrm);
 300
 301 MODULE_AUTHOR("Rudolf Marek <r.marek@assembler.cz>");
 302
 303 MODULE_DESCRIPTION("hwmon-vid driver");
 304 MODULE_LICENSE("GPL");