xref: /openbmc/linux/drivers/hwmon/hwmon-vid.c (revision e3b9f1e8)
1 /*
2  * hwmon-vid.c - VID/VRM/VRD voltage conversions
3  *
4  * Copyright (c) 2004 Rudolf Marek <r.marek@assembler.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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
26 
27 #include <linux/module.h>
28 #include <linux/kernel.h>
29 #include <linux/hwmon-vid.h>
30 
31 /*
32  * Common code for decoding VID pins.
33  *
34  * References:
35  *
36  * For VRM 8.4 to 9.1, "VRM x.y DC-DC Converter Design Guidelines",
37  * available at http://developer.intel.com/.
38  *
39  * For VRD 10.0 and up, "VRD x.y Design Guide",
40  * available at http://developer.intel.com/.
41  *
42  * AMD Athlon 64 and AMD Opteron Processors, AMD Publication 26094,
43  * http://support.amd.com/us/Processor_TechDocs/26094.PDF
44  * Table 74. VID Code Voltages
45  * This corresponds to an arbitrary VRM code of 24 in the functions below.
46  * These CPU models (K8 revision <= E) have 5 VID pins. See also:
47  * Revision Guide for AMD Athlon 64 and AMD Opteron Processors, AMD Publication 25759,
48  * http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/25759.pdf
49  *
50  * AMD NPT Family 0Fh Processors, AMD Publication 32559,
51  * http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/32559.pdf
52  * Table 71. VID Code Voltages
53  * This corresponds to an arbitrary VRM code of 25 in the functions below.
54  * These CPU models (K8 revision >= F) have 6 VID pins. See also:
55  * Revision Guide for AMD NPT Family 0Fh Processors, AMD Publication 33610,
56  * http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/33610.pdf
57  *
58  * The 17 specification is in fact Intel Mobile Voltage Positioning -
59  * (IMVP-II). You can find more information in the datasheet of Max1718
60  * http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2452
61  *
62  * The 13 specification corresponds to the Intel Pentium M series. There
63  * doesn't seem to be any named specification for these. The conversion
64  * tables are detailed directly in the various Pentium M datasheets:
65  * http://www.intel.com/design/intarch/pentiumm/docs_pentiumm.htm
66  *
67  * The 14 specification corresponds to Intel Core series. There
68  * doesn't seem to be any named specification for these. The conversion
69  * tables are detailed directly in the various Pentium Core datasheets:
70  * http://www.intel.com/design/mobile/datashts/309221.htm
71  *
72  * The 110 (VRM 11) specification corresponds to Intel Conroe based series.
73  * http://www.intel.com/design/processor/applnots/313214.htm
74  */
75 
76 /*
77  * vrm is the VRM/VRD document version multiplied by 10.
78  * val is the 4-bit or more VID code.
79  * Returned value is in mV to avoid floating point in the kernel.
80  * Some VID have some bits in uV scale, this is rounded to mV.
81  */
82 int vid_from_reg(int val, u8 vrm)
83 {
84 	int vid;
85 
86 	switch (vrm) {
87 
88 	case 100:		/* VRD 10.0 */
89 		/* compute in uV, round to mV */
90 		val &= 0x3f;
91 		if ((val & 0x1f) == 0x1f)
92 			return 0;
93 		if ((val & 0x1f) <= 0x09 || val == 0x0a)
94 			vid = 1087500 - (val & 0x1f) * 25000;
95 		else
96 			vid = 1862500 - (val & 0x1f) * 25000;
97 		if (val & 0x20)
98 			vid -= 12500;
99 		return (vid + 500) / 1000;
100 
101 	case 110:		/* Intel Conroe */
102 				/* compute in uV, round to mV */
103 		val &= 0xff;
104 		if (val < 0x02 || val > 0xb2)
105 			return 0;
106 		return (1600000 - (val - 2) * 6250 + 500) / 1000;
107 
108 	case 24:		/* Athlon64 & Opteron */
109 		val &= 0x1f;
110 		if (val == 0x1f)
111 			return 0;
112 				/* fall through */
113 	case 25:		/* AMD NPT 0Fh */
114 		val &= 0x3f;
115 		return (val < 32) ? 1550 - 25 * val
116 			: 775 - (25 * (val - 31)) / 2;
117 
118 	case 26:		/* AMD family 10h to 15h, serial VID */
119 		val &= 0x7f;
120 		if (val >= 0x7c)
121 			return 0;
122 		return DIV_ROUND_CLOSEST(15500 - 125 * val, 10);
123 
124 	case 91:		/* VRM 9.1 */
125 	case 90:		/* VRM 9.0 */
126 		val &= 0x1f;
127 		return val == 0x1f ? 0 :
128 				     1850 - val * 25;
129 
130 	case 85:		/* VRM 8.5 */
131 		val &= 0x1f;
132 		return (val & 0x10  ? 25 : 0) +
133 		       ((val & 0x0f) > 0x04 ? 2050 : 1250) -
134 		       ((val & 0x0f) * 50);
135 
136 	case 84:		/* VRM 8.4 */
137 		val &= 0x0f;
138 				/* fall through */
139 	case 82:		/* VRM 8.2 */
140 		val &= 0x1f;
141 		return val == 0x1f ? 0 :
142 		       val & 0x10  ? 5100 - (val) * 100 :
143 				     2050 - (val) * 50;
144 	case 17:		/* Intel IMVP-II */
145 		val &= 0x1f;
146 		return val & 0x10 ? 975 - (val & 0xF) * 25 :
147 				    1750 - val * 50;
148 	case 13:
149 	case 131:
150 		val &= 0x3f;
151 		/* Exception for Eden ULV 500 MHz */
152 		if (vrm == 131 && val == 0x3f)
153 			val++;
154 		return 1708 - val * 16;
155 	case 14:		/* Intel Core */
156 				/* compute in uV, round to mV */
157 		val &= 0x7f;
158 		return val > 0x77 ? 0 : (1500000 - (val * 12500) + 500) / 1000;
159 	default:		/* report 0 for unknown */
160 		if (vrm)
161 			pr_warn("Requested unsupported VRM version (%u)\n",
162 				(unsigned int)vrm);
163 		return 0;
164 	}
165 }
166 EXPORT_SYMBOL(vid_from_reg);
167 
168 /*
169  * After this point is the code to automatically determine which
170  * VRM/VRD specification should be used depending on the CPU.
171  */
172 
173 struct vrm_model {
174 	u8 vendor;
175 	u8 family;
176 	u8 model_from;
177 	u8 model_to;
178 	u8 stepping_to;
179 	u8 vrm_type;
180 };
181 
182 #define ANY 0xFF
183 
184 #ifdef CONFIG_X86
185 
186 /*
187  * The stepping_to parameter is highest acceptable stepping for current line.
188  * The model match must be exact for 4-bit values. For model values 0x10
189  * and above (extended model), all models below the parameter will match.
190  */
191 
192 static struct vrm_model vrm_models[] = {
193 	{X86_VENDOR_AMD, 0x6, 0x0, ANY, ANY, 90},	/* Athlon Duron etc */
194 	{X86_VENDOR_AMD, 0xF, 0x0, 0x3F, ANY, 24},	/* Athlon 64, Opteron */
195 	/*
196 	 * In theory, all NPT family 0Fh processors have 6 VID pins and should
197 	 * thus use vrm 25, however in practice not all mainboards route the
198 	 * 6th VID pin because it is never needed. So we use the 5 VID pin
199 	 * variant (vrm 24) for the models which exist today.
200 	 */
201 	{X86_VENDOR_AMD, 0xF, 0x40, 0x7F, ANY, 24},	/* NPT family 0Fh */
202 	{X86_VENDOR_AMD, 0xF, 0x80, ANY, ANY, 25},	/* future fam. 0Fh */
203 	{X86_VENDOR_AMD, 0x10, 0x0, ANY, ANY, 25},	/* NPT family 10h */
204 	{X86_VENDOR_AMD, 0x11, 0x0, ANY, ANY, 26},	/* family 11h */
205 	{X86_VENDOR_AMD, 0x12, 0x0, ANY, ANY, 26},	/* family 12h */
206 	{X86_VENDOR_AMD, 0x14, 0x0, ANY, ANY, 26},	/* family 14h */
207 	{X86_VENDOR_AMD, 0x15, 0x0, ANY, ANY, 26},	/* family 15h */
208 
209 	{X86_VENDOR_INTEL, 0x6, 0x0, 0x6, ANY, 82},	/* Pentium Pro,
210 							 * Pentium II, Xeon,
211 							 * Mobile Pentium,
212 							 * Celeron */
213 	{X86_VENDOR_INTEL, 0x6, 0x7, 0x7, ANY, 84},	/* Pentium III, Xeon */
214 	{X86_VENDOR_INTEL, 0x6, 0x8, 0x8, ANY, 82},	/* Pentium III, Xeon */
215 	{X86_VENDOR_INTEL, 0x6, 0x9, 0x9, ANY, 13},	/* Pentium M (130 nm) */
216 	{X86_VENDOR_INTEL, 0x6, 0xA, 0xA, ANY, 82},	/* Pentium III Xeon */
217 	{X86_VENDOR_INTEL, 0x6, 0xB, 0xB, ANY, 85},	/* Tualatin */
218 	{X86_VENDOR_INTEL, 0x6, 0xD, 0xD, ANY, 13},	/* Pentium M (90 nm) */
219 	{X86_VENDOR_INTEL, 0x6, 0xE, 0xE, ANY, 14},	/* Intel Core (65 nm) */
220 	{X86_VENDOR_INTEL, 0x6, 0xF, ANY, ANY, 110},	/* Intel Conroe and
221 							 * later */
222 	{X86_VENDOR_INTEL, 0xF, 0x0, 0x0, ANY, 90},	/* P4 */
223 	{X86_VENDOR_INTEL, 0xF, 0x1, 0x1, ANY, 90},	/* P4 Willamette */
224 	{X86_VENDOR_INTEL, 0xF, 0x2, 0x2, ANY, 90},	/* P4 Northwood */
225 	{X86_VENDOR_INTEL, 0xF, 0x3, ANY, ANY, 100},	/* Prescott and above
226 							 * assume VRD 10 */
227 
228 	{X86_VENDOR_CENTAUR, 0x6, 0x7, 0x7, ANY, 85},	/* Eden ESP/Ezra */
229 	{X86_VENDOR_CENTAUR, 0x6, 0x8, 0x8, 0x7, 85},	/* Ezra T */
230 	{X86_VENDOR_CENTAUR, 0x6, 0x9, 0x9, 0x7, 85},	/* Nehemiah */
231 	{X86_VENDOR_CENTAUR, 0x6, 0x9, 0x9, ANY, 17},	/* C3-M, Eden-N */
232 	{X86_VENDOR_CENTAUR, 0x6, 0xA, 0xA, 0x7, 0},	/* No information */
233 	{X86_VENDOR_CENTAUR, 0x6, 0xA, 0xA, ANY, 13},	/* C7-M, C7,
234 							 * Eden (Esther) */
235 	{X86_VENDOR_CENTAUR, 0x6, 0xD, 0xD, ANY, 134},	/* C7-D, C7-M, C7,
236 							 * Eden (Esther) */
237 };
238 
239 /*
240  * Special case for VIA model D: there are two different possible
241  * VID tables, so we have to figure out first, which one must be
242  * used. This resolves temporary drm value 134 to 14 (Intel Core
243  * 7-bit VID), 13 (Pentium M 6-bit VID) or 131 (Pentium M 6-bit VID
244  * + quirk for Eden ULV 500 MHz).
245  * Note: something similar might be needed for model A, I'm not sure.
246  */
247 static u8 get_via_model_d_vrm(void)
248 {
249 	unsigned int vid, brand, __maybe_unused dummy;
250 	static const char *brands[4] = {
251 		"C7-M", "C7", "Eden", "C7-D"
252 	};
253 
254 	rdmsr(0x198, dummy, vid);
255 	vid &= 0xff;
256 
257 	rdmsr(0x1154, brand, dummy);
258 	brand = ((brand >> 4) ^ (brand >> 2)) & 0x03;
259 
260 	if (vid > 0x3f) {
261 		pr_info("Using %d-bit VID table for VIA %s CPU\n",
262 			7, brands[brand]);
263 		return 14;
264 	} else {
265 		pr_info("Using %d-bit VID table for VIA %s CPU\n",
266 			6, brands[brand]);
267 		/* Enable quirk for Eden */
268 		return brand == 2 ? 131 : 13;
269 	}
270 }
271 
272 static u8 find_vrm(u8 family, u8 model, u8 stepping, u8 vendor)
273 {
274 	int i;
275 
276 	for (i = 0; i < ARRAY_SIZE(vrm_models); i++) {
277 		if (vendor == vrm_models[i].vendor &&
278 		    family == vrm_models[i].family &&
279 		    model >= vrm_models[i].model_from &&
280 		    model <= vrm_models[i].model_to &&
281 		    stepping <= vrm_models[i].stepping_to)
282 			return vrm_models[i].vrm_type;
283 	}
284 
285 	return 0;
286 }
287 
288 u8 vid_which_vrm(void)
289 {
290 	struct cpuinfo_x86 *c = &cpu_data(0);
291 	u8 vrm_ret;
292 
293 	if (c->x86 < 6)		/* Any CPU with family lower than 6 */
294 		return 0;	/* doesn't have VID */
295 
296 	vrm_ret = find_vrm(c->x86, c->x86_model, c->x86_stepping, c->x86_vendor);
297 	if (vrm_ret == 134)
298 		vrm_ret = get_via_model_d_vrm();
299 	if (vrm_ret == 0)
300 		pr_info("Unknown VRM version of your x86 CPU\n");
301 	return vrm_ret;
302 }
303 
304 /* and now for something completely different for the non-x86 world */
305 #else
306 u8 vid_which_vrm(void)
307 {
308 	pr_info("Unknown VRM version of your CPU\n");
309 	return 0;
310 }
311 #endif
312 EXPORT_SYMBOL(vid_which_vrm);
313 
314 MODULE_AUTHOR("Rudolf Marek <r.marek@assembler.cz>");
315 
316 MODULE_DESCRIPTION("hwmon-vid driver");
317 MODULE_LICENSE("GPL");
318