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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Pentium 4/Xeon CPU on demand clock modulation/speed scaling
3 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
4 * (C) 2002 Zwane Mwaikambo <zwane@commfireservices.com>
5 * (C) 2002 Arjan van de Ven <arjanv@redhat.com>
6 * (C) 2002 Tora T. Engstad
7 * All Rights Reserved
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; either version
12 * 2 of the License, or (at your option) any later version.
13 *
14 * The author(s) of this software shall not be held liable for damages
15 * of any nature resulting due to the use of this software. This
16 * software is provided AS-IS with no warranties.
Dave Jones32ee8c32006-02-28 00:43:23 -050017 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070018 * Date Errata Description
19 * 20020525 N44, O17 12.5% or 25% DC causes lockup
20 *
21 */
22
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#include <linux/kernel.h>
Dave Jones32ee8c32006-02-28 00:43:23 -050024#include <linux/module.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#include <linux/init.h>
26#include <linux/smp.h>
27#include <linux/cpufreq.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028#include <linux/cpumask.h>
Dave Jonesbbfebd62009-01-17 23:55:22 -050029#include <linux/timex.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
Dave Jones32ee8c32006-02-28 00:43:23 -050031#include <asm/processor.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032#include <asm/msr.h>
Matthias-Christian Ott199785e2009-02-20 20:52:17 -050033#include <asm/timer.h>
Andi Kleenfa8031a2012-01-26 00:09:12 +010034#include <asm/cpu_device_id.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070035
36#include "speedstep-lib.h"
37
38#define PFX "p4-clockmod: "
Linus Torvalds1da177e2005-04-16 15:20:36 -070039
40/*
41 * Duty Cycle (3bits), note DC_DISABLE is not specified in
42 * intel docs i just use it to mean disable
43 */
44enum {
45 DC_RESV, DC_DFLT, DC_25PT, DC_38PT, DC_50PT,
46 DC_64PT, DC_75PT, DC_88PT, DC_DISABLE
47};
48
49#define DC_ENTRIES 8
50
51
52static int has_N44_O17_errata[NR_CPUS];
53static unsigned int stock_freq;
54static struct cpufreq_driver p4clockmod_driver;
55static unsigned int cpufreq_p4_get(unsigned int cpu);
56
57static int cpufreq_p4_setdc(unsigned int cpu, unsigned int newstate)
58{
59 u32 l, h;
60
Dave Jonesbbfebd62009-01-17 23:55:22 -050061 if (!cpu_online(cpu) ||
62 (newstate > DC_DISABLE) || (newstate == DC_RESV))
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 return -EINVAL;
64
Alexey Dobriyan551948b2007-03-19 19:17:00 +030065 rdmsr_on_cpu(cpu, MSR_IA32_THERM_STATUS, &l, &h);
Linus Torvalds1da177e2005-04-16 15:20:36 -070066
67 if (l & 0x01)
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +020068 pr_debug("CPU#%d currently thermal throttled\n", cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -070069
Dave Jonesbbfebd62009-01-17 23:55:22 -050070 if (has_N44_O17_errata[cpu] &&
71 (newstate == DC_25PT || newstate == DC_DFLT))
Linus Torvalds1da177e2005-04-16 15:20:36 -070072 newstate = DC_38PT;
73
Alexey Dobriyan551948b2007-03-19 19:17:00 +030074 rdmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, &l, &h);
Linus Torvalds1da177e2005-04-16 15:20:36 -070075 if (newstate == DC_DISABLE) {
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +020076 pr_debug("CPU#%d disabling modulation\n", cpu);
Alexey Dobriyan551948b2007-03-19 19:17:00 +030077 wrmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, l & ~(1<<4), h);
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 } else {
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +020079 pr_debug("CPU#%d setting duty cycle to %d%%\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -070080 cpu, ((125 * newstate) / 10));
Dave Jones32ee8c32006-02-28 00:43:23 -050081 /* bits 63 - 5 : reserved
Linus Torvalds1da177e2005-04-16 15:20:36 -070082 * bit 4 : enable/disable
83 * bits 3-1 : duty cycle
84 * bit 0 : reserved
85 */
86 l = (l & ~14);
87 l = l | (1<<4) | ((newstate & 0x7)<<1);
Alexey Dobriyan551948b2007-03-19 19:17:00 +030088 wrmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, l, h);
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 }
90
91 return 0;
92}
93
94
95static struct cpufreq_frequency_table p4clockmod_table[] = {
96 {DC_RESV, CPUFREQ_ENTRY_INVALID},
97 {DC_DFLT, 0},
98 {DC_25PT, 0},
99 {DC_38PT, 0},
100 {DC_50PT, 0},
101 {DC_64PT, 0},
102 {DC_75PT, 0},
103 {DC_88PT, 0},
104 {DC_DISABLE, 0},
105 {DC_RESV, CPUFREQ_TABLE_END},
106};
107
108
109static int cpufreq_p4_target(struct cpufreq_policy *policy,
110 unsigned int target_freq,
111 unsigned int relation)
112{
113 unsigned int newstate = DC_RESV;
114 struct cpufreq_freqs freqs;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115 int i;
116
Dave Jonesbbfebd62009-01-17 23:55:22 -0500117 if (cpufreq_frequency_table_target(policy, &p4clockmod_table[0],
118 target_freq, relation, &newstate))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 return -EINVAL;
120
121 freqs.old = cpufreq_p4_get(policy->cpu);
122 freqs.new = stock_freq * p4clockmod_table[newstate].index / 8;
123
124 if (freqs.new == freqs.old)
125 return 0;
126
127 /* notifiers */
Viresh Kumarb43a7ff2013-03-24 11:56:43 +0530128 cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129
Dave Jonesbbfebd62009-01-17 23:55:22 -0500130 /* run on each logical CPU,
131 * see section 13.15.3 of IA32 Intel Architecture Software
Dave Jones32ee8c32006-02-28 00:43:23 -0500132 * Developer's Manual, Volume 3
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 */
Rusty Russell835481d2009-01-04 05:18:06 -0800134 for_each_cpu(i, policy->cpus)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 cpufreq_p4_setdc(i, p4clockmod_table[newstate].index);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136
137 /* notifiers */
Viresh Kumarb43a7ff2013-03-24 11:56:43 +0530138 cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139
140 return 0;
141}
142
143
144static int cpufreq_p4_verify(struct cpufreq_policy *policy)
145{
146 return cpufreq_frequency_table_verify(policy, &p4clockmod_table[0]);
147}
148
149
150static unsigned int cpufreq_p4_get_frequency(struct cpuinfo_x86 *c)
151{
Dominik Brodowski4e746632006-10-31 12:44:08 -0500152 if (c->x86 == 0x06) {
153 if (cpu_has(c, X86_FEATURE_EST))
Naga Chumbalkar853cee22011-02-15 17:44:11 +0000154 printk_once(KERN_WARNING PFX "Warning: EST-capable "
155 "CPU detected. The acpi-cpufreq module offers "
156 "voltage scaling in addition to frequency "
Dave Jonesbbfebd62009-01-17 23:55:22 -0500157 "scaling. You should use that instead of "
158 "p4-clockmod, if possible.\n");
Dominik Brodowski4e746632006-10-31 12:44:08 -0500159 switch (c->x86_model) {
160 case 0x0E: /* Core */
161 case 0x0F: /* Core Duo */
Herton Ronaldo Krzesinski85291542008-11-15 17:02:46 -0200162 case 0x16: /* Celeron Core */
Jarod Wilson43195032009-03-06 20:24:57 +0000163 case 0x1C: /* Atom */
Dominik Brodowski4e746632006-10-31 12:44:08 -0500164 p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
Dave Jonesbbfebd62009-01-17 23:55:22 -0500165 return speedstep_get_frequency(SPEEDSTEP_CPU_PCORE);
Dominik Brodowski4e746632006-10-31 12:44:08 -0500166 case 0x0D: /* Pentium M (Dothan) */
167 p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
168 /* fall through */
169 case 0x09: /* Pentium M (Banias) */
Dave Jonesbbfebd62009-01-17 23:55:22 -0500170 return speedstep_get_frequency(SPEEDSTEP_CPU_PM);
Dominik Brodowski4e746632006-10-31 12:44:08 -0500171 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 }
173
Dave Jones9d1f44e2010-08-03 13:47:30 -0400174 if (c->x86 != 0xF)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176
177 /* on P-4s, the TSC runs with constant frequency independent whether
178 * throttling is active or not. */
179 p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
180
Dave Jonesbbfebd62009-01-17 23:55:22 -0500181 if (speedstep_detect_processor() == SPEEDSTEP_CPU_P4M) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 printk(KERN_WARNING PFX "Warning: Pentium 4-M detected. "
183 "The speedstep-ich or acpi cpufreq modules offer "
184 "voltage scaling in addition of frequency scaling. "
185 "You should use either one instead of p4-clockmod, "
186 "if possible.\n");
Dave Jonesbbfebd62009-01-17 23:55:22 -0500187 return speedstep_get_frequency(SPEEDSTEP_CPU_P4M);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188 }
189
Dave Jonesbbfebd62009-01-17 23:55:22 -0500190 return speedstep_get_frequency(SPEEDSTEP_CPU_P4D);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191}
192
Dave Jones32ee8c32006-02-28 00:43:23 -0500193
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194
195static int cpufreq_p4_cpu_init(struct cpufreq_policy *policy)
196{
Mike Travis92cb7612007-10-19 20:35:04 +0200197 struct cpuinfo_x86 *c = &cpu_data(policy->cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 int cpuid = 0;
199 unsigned int i;
200
201#ifdef CONFIG_SMP
Rusty Russell7ad728f2009-03-13 14:49:50 +1030202 cpumask_copy(policy->cpus, cpu_sibling_mask(policy->cpu));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203#endif
204
205 /* Errata workaround */
206 cpuid = (c->x86 << 8) | (c->x86_model << 4) | c->x86_mask;
207 switch (cpuid) {
208 case 0x0f07:
209 case 0x0f0a:
210 case 0x0f11:
211 case 0x0f12:
212 has_N44_O17_errata[policy->cpu] = 1;
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200213 pr_debug("has errata -- disabling low frequencies\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 }
Dave Jones32ee8c32006-02-28 00:43:23 -0500215
Matthias-Christian Ott199785e2009-02-20 20:52:17 -0500216 if (speedstep_detect_processor() == SPEEDSTEP_CPU_P4D &&
217 c->x86_model < 2) {
218 /* switch to maximum frequency and measure result */
219 cpufreq_p4_setdc(policy->cpu, DC_DISABLE);
220 recalibrate_cpu_khz();
221 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222 /* get max frequency */
223 stock_freq = cpufreq_p4_get_frequency(c);
224 if (!stock_freq)
225 return -EINVAL;
226
227 /* table init */
Dave Jonesbbfebd62009-01-17 23:55:22 -0500228 for (i = 1; (p4clockmod_table[i].frequency != CPUFREQ_TABLE_END); i++) {
229 if ((i < 2) && (has_N44_O17_errata[policy->cpu]))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230 p4clockmod_table[i].frequency = CPUFREQ_ENTRY_INVALID;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 else
232 p4clockmod_table[i].frequency = (stock_freq * i)/8;
233 }
234 cpufreq_frequency_table_get_attr(p4clockmod_table, policy->cpu);
Dave Jones32ee8c32006-02-28 00:43:23 -0500235
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 /* cpuinfo and default policy values */
Dave Jones36e8abf2009-03-05 00:16:26 -0500237
238 /* the transition latency is set to be 1 higher than the maximum
239 * transition latency of the ondemand governor */
240 policy->cpuinfo.transition_latency = 10000001;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241 policy->cur = stock_freq;
242
243 return cpufreq_frequency_table_cpuinfo(policy, &p4clockmod_table[0]);
244}
245
246
247static int cpufreq_p4_cpu_exit(struct cpufreq_policy *policy)
248{
Dave Jones32ee8c32006-02-28 00:43:23 -0500249 cpufreq_frequency_table_put_attr(policy->cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250 return 0;
251}
252
253static unsigned int cpufreq_p4_get(unsigned int cpu)
254{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255 u32 l, h;
256
Alexey Dobriyan551948b2007-03-19 19:17:00 +0300257 rdmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, &l, &h);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258
259 if (l & 0x10) {
260 l = l >> 1;
261 l &= 0x7;
262 } else
263 l = DC_DISABLE;
264
265 if (l != DC_DISABLE)
Dave Jonesbbfebd62009-01-17 23:55:22 -0500266 return stock_freq * l / 8;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267
268 return stock_freq;
269}
270
Dave Jonesbbfebd62009-01-17 23:55:22 -0500271static struct freq_attr *p4clockmod_attr[] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272 &cpufreq_freq_attr_scaling_available_freqs,
273 NULL,
274};
275
276static struct cpufreq_driver p4clockmod_driver = {
Dave Jones32ee8c32006-02-28 00:43:23 -0500277 .verify = cpufreq_p4_verify,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 .target = cpufreq_p4_target,
279 .init = cpufreq_p4_cpu_init,
280 .exit = cpufreq_p4_cpu_exit,
281 .get = cpufreq_p4_get,
282 .name = "p4-clockmod",
283 .owner = THIS_MODULE,
284 .attr = p4clockmod_attr,
285};
286
Andi Kleenfa8031a2012-01-26 00:09:12 +0100287static const struct x86_cpu_id cpufreq_p4_id[] = {
288 { X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY, X86_FEATURE_ACC },
289 {}
290};
291
292/*
293 * Intentionally no MODULE_DEVICE_TABLE here: this driver should not
294 * be auto loaded. Please don't add one.
295 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296
297static int __init cpufreq_p4_init(void)
Dave Jones32ee8c32006-02-28 00:43:23 -0500298{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 int ret;
300
301 /*
Dave Jones32ee8c32006-02-28 00:43:23 -0500302 * THERM_CONTROL is architectural for IA32 now, so
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303 * we can rely on the capability checks
304 */
Andi Kleenfa8031a2012-01-26 00:09:12 +0100305 if (!x86_match_cpu(cpufreq_p4_id) || !boot_cpu_has(X86_FEATURE_ACPI))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306 return -ENODEV;
307
308 ret = cpufreq_register_driver(&p4clockmod_driver);
309 if (!ret)
Dave Jonesbbfebd62009-01-17 23:55:22 -0500310 printk(KERN_INFO PFX "P4/Xeon(TM) CPU On-Demand Clock "
311 "Modulation available\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312
Dave Jonesbbfebd62009-01-17 23:55:22 -0500313 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314}
315
316
317static void __exit cpufreq_p4_exit(void)
318{
319 cpufreq_unregister_driver(&p4clockmod_driver);
320}
321
322
Dave Jonesbbfebd62009-01-17 23:55:22 -0500323MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>");
324MODULE_DESCRIPTION("cpufreq driver for Pentium(TM) 4/Xeon(TM)");
325MODULE_LICENSE("GPL");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326
327late_initcall(cpufreq_p4_init);
328module_exit(cpufreq_p4_exit);