2 hwmon-vid.c - VID/VRM/VRD voltage conversions
4 Copyright (c) 2004 Rudolf Marek <r.marek@sh.cvut.cz>
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>
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.
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.
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.
25 #include <linux/config.h>
26 #include <linux/module.h>
27 #include <linux/kernel.h>
28 #include <linux/hwmon-vid.h>
31 Common code for decoding VID pins.
35 For VRM 8.4 to 9.1, "VRM x.y DC-DC Converter Design Guidelines",
36 available at http://developer.intel.com/.
38 For VRD 10.0 and up, "VRD x.y Design Guide",
39 available at http://developer.intel.com/.
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
46 Opteron VID encoding is:
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)
66 case 100: /* VRD 10.0 */
67 if((val & 0x1f) == 0x1f)
69 if((val & 0x1f) <= 0x09 || val == 0x0a)
70 vid = 10875 - (val & 0x1f) * 250;
72 vid = 18625 - (val & 0x1f) * 250;
75 vid /= 10; /* only return 3 dec. places for now */
78 case 24: /* Opteron processor */
79 return(val == 0x1f ? 0 : 1550 - val * 25);
81 case 91: /* VRM 9.1 */
82 case 90: /* VRM 9.0 */
83 return(val == 0x1f ? 0 :
86 case 85: /* VRM 8.5 */
87 return((val & 0x10 ? 25 : 0) +
88 ((val & 0x0f) > 0x04 ? 2050 : 1250) -
91 case 84: /* VRM 8.4 */
94 default: /* VRM 8.2 */
95 return(val == 0x1f ? 0 :
96 val & 0x10 ? 5100 - (val) * 100 :
103 After this point is the code to automatically determine which
104 VRM/VRD specification should be used depending on the CPU.
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, 0x3, 100}, /* P4 Prescott */
126 {X86_VENDOR_INTEL, 0xF, ANY, 90}, /* P4 before Prescott */
127 {X86_VENDOR_INTEL, 0x10,ANY, 0}, /* Itanium 2 */
128 {X86_VENDOR_UNKNOWN, ANY, ANY, 0} /* stop here */
131 static int find_vrm(u8 eff_family, u8 eff_model, u8 vendor)
135 while (vrm_models[i].vendor!=X86_VENDOR_UNKNOWN) {
136 if (vrm_models[i].vendor==vendor)
137 if ((vrm_models[i].eff_family==eff_family)
138 && ((vrm_models[i].eff_model==eff_model) ||
139 (vrm_models[i].eff_model==ANY)))
140 return vrm_models[i].vrm_type;
147 int vid_which_vrm(void)
149 struct cpuinfo_x86 *c = cpu_data;
151 u8 eff_family, eff_model;
154 if (c->x86 < 6) /* Any CPU with family lower than 6 */
155 return 0; /* doesn't have VID and/or CPUID */
158 eff_family = ((eax & 0x00000F00)>>8);
159 eff_model = ((eax & 0x000000F0)>>4);
160 if (eff_family == 0xF) { /* use extended model & family */
161 eff_family += ((eax & 0x00F00000)>>20);
162 eff_model += ((eax & 0x000F0000)>>16)<<4;
164 vrm_ret = find_vrm(eff_family,eff_model,c->x86_vendor);
166 printk(KERN_INFO "hwmon-vid: Unknown VRM version of your "
171 /* and now something completely different for the non-x86 world */
173 int vid_which_vrm(void)
175 printk(KERN_INFO "hwmon-vid: Unknown VRM version of your CPU\n");
180 EXPORT_SYMBOL(vid_from_reg);
181 EXPORT_SYMBOL(vid_which_vrm);
183 MODULE_AUTHOR("Rudolf Marek <r.marek@sh.cvut.cz>");
185 MODULE_DESCRIPTION("hwmon-vid driver");
186 MODULE_LICENSE("GPL");