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1/*
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.
17 *
18 * Date Errata Description
19 * 20020525 N44, O17 12.5% or 25% DC causes lockup
20 *
21 */
22
23#include <linux/kernel.h>
24#include <linux/module.h>
25#include <linux/init.h>
26#include <linux/smp.h>
27#include <linux/cpufreq.h>
28#include <linux/cpumask.h>
29#include <linux/timex.h>
30
31#include <asm/processor.h>
32#include <asm/msr.h>
33#include <asm/timer.h>
34
35#include "speedstep-lib.h"
36
37#define PFX "p4-clockmod: "
38
39/*
40 * Duty Cycle (3bits), note DC_DISABLE is not specified in
41 * intel docs i just use it to mean disable
42 */
43enum {
44 DC_RESV, DC_DFLT, DC_25PT, DC_38PT, DC_50PT,
45 DC_64PT, DC_75PT, DC_88PT, DC_DISABLE
46};
47
48#define DC_ENTRIES 8
49
50
51static int has_N44_O17_errata[NR_CPUS];
52static unsigned int stock_freq;
53static struct cpufreq_driver p4clockmod_driver;
54static unsigned int cpufreq_p4_get(unsigned int cpu);
55
56static int cpufreq_p4_setdc(unsigned int cpu, unsigned int newstate)
57{
58 u32 l, h;
59
60 if (!cpu_online(cpu) ||
61 (newstate > DC_DISABLE) || (newstate == DC_RESV))
62 return -EINVAL;
63
64 rdmsr_on_cpu(cpu, MSR_IA32_THERM_STATUS, &l, &h);
65
66 if (l & 0x01)
67 pr_debug("CPU#%d currently thermal throttled\n", cpu);
68
69 if (has_N44_O17_errata[cpu] &&
70 (newstate == DC_25PT || newstate == DC_DFLT))
71 newstate = DC_38PT;
72
73 rdmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, &l, &h);
74 if (newstate == DC_DISABLE) {
75 pr_debug("CPU#%d disabling modulation\n", cpu);
76 wrmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, l & ~(1<<4), h);
77 } else {
78 pr_debug("CPU#%d setting duty cycle to %d%%\n",
79 cpu, ((125 * newstate) / 10));
80 /* bits 63 - 5 : reserved
81 * bit 4 : enable/disable
82 * bits 3-1 : duty cycle
83 * bit 0 : reserved
84 */
85 l = (l & ~14);
86 l = l | (1<<4) | ((newstate & 0x7)<<1);
87 wrmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, l, h);
88 }
89
90 return 0;
91}
92
93
94static struct cpufreq_frequency_table p4clockmod_table[] = {
95 {DC_RESV, CPUFREQ_ENTRY_INVALID},
96 {DC_DFLT, 0},
97 {DC_25PT, 0},
98 {DC_38PT, 0},
99 {DC_50PT, 0},
100 {DC_64PT, 0},
101 {DC_75PT, 0},
102 {DC_88PT, 0},
103 {DC_DISABLE, 0},
104 {DC_RESV, CPUFREQ_TABLE_END},
105};
106
107
108static int cpufreq_p4_target(struct cpufreq_policy *policy,
109 unsigned int target_freq,
110 unsigned int relation)
111{
112 unsigned int newstate = DC_RESV;
113 struct cpufreq_freqs freqs;
114 int i;
115
116 if (cpufreq_frequency_table_target(policy, &p4clockmod_table[0],
117 target_freq, relation, &newstate))
118 return -EINVAL;
119
120 freqs.old = cpufreq_p4_get(policy->cpu);
121 freqs.new = stock_freq * p4clockmod_table[newstate].index / 8;
122
123 if (freqs.new == freqs.old)
124 return 0;
125
126 /* notifiers */
127 for_each_cpu(i, policy->cpus) {
128 freqs.cpu = i;
129 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
130 }
131
132 /* run on each logical CPU,
133 * see section 13.15.3 of IA32 Intel Architecture Software
134 * Developer's Manual, Volume 3
135 */
136 for_each_cpu(i, policy->cpus)
137 cpufreq_p4_setdc(i, p4clockmod_table[newstate].index);
138
139 /* notifiers */
140 for_each_cpu(i, policy->cpus) {
141 freqs.cpu = i;
142 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
143 }
144
145 return 0;
146}
147
148
149static int cpufreq_p4_verify(struct cpufreq_policy *policy)
150{
151 return cpufreq_frequency_table_verify(policy, &p4clockmod_table[0]);
152}
153
154
155static unsigned int cpufreq_p4_get_frequency(struct cpuinfo_x86 *c)
156{
157 if (c->x86 == 0x06) {
158 if (cpu_has(c, X86_FEATURE_EST))
159 printk_once(KERN_WARNING PFX "Warning: EST-capable "
160 "CPU detected. The acpi-cpufreq module offers "
161 "voltage scaling in addition to frequency "
162 "scaling. You should use that instead of "
163 "p4-clockmod, if possible.\n");
164 switch (c->x86_model) {
165 case 0x0E: /* Core */
166 case 0x0F: /* Core Duo */
167 case 0x16: /* Celeron Core */
168 case 0x1C: /* Atom */
169 p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
170 return speedstep_get_frequency(SPEEDSTEP_CPU_PCORE);
171 case 0x0D: /* Pentium M (Dothan) */
172 p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
173 /* fall through */
174 case 0x09: /* Pentium M (Banias) */
175 return speedstep_get_frequency(SPEEDSTEP_CPU_PM);
176 }
177 }
178
179 if (c->x86 != 0xF)
180 return 0;
181
182 /* on P-4s, the TSC runs with constant frequency independent whether
183 * throttling is active or not. */
184 p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
185
186 if (speedstep_detect_processor() == SPEEDSTEP_CPU_P4M) {
187 printk(KERN_WARNING PFX "Warning: Pentium 4-M detected. "
188 "The speedstep-ich or acpi cpufreq modules offer "
189 "voltage scaling in addition of frequency scaling. "
190 "You should use either one instead of p4-clockmod, "
191 "if possible.\n");
192 return speedstep_get_frequency(SPEEDSTEP_CPU_P4M);
193 }
194
195 return speedstep_get_frequency(SPEEDSTEP_CPU_P4D);
196}
197
198
199
200static int cpufreq_p4_cpu_init(struct cpufreq_policy *policy)
201{
202 struct cpuinfo_x86 *c = &cpu_data(policy->cpu);
203 int cpuid = 0;
204 unsigned int i;
205
206#ifdef CONFIG_SMP
207 cpumask_copy(policy->cpus, cpu_sibling_mask(policy->cpu));
208#endif
209
210 /* Errata workaround */
211 cpuid = (c->x86 << 8) | (c->x86_model << 4) | c->x86_mask;
212 switch (cpuid) {
213 case 0x0f07:
214 case 0x0f0a:
215 case 0x0f11:
216 case 0x0f12:
217 has_N44_O17_errata[policy->cpu] = 1;
218 pr_debug("has errata -- disabling low frequencies\n");
219 }
220
221 if (speedstep_detect_processor() == SPEEDSTEP_CPU_P4D &&
222 c->x86_model < 2) {
223 /* switch to maximum frequency and measure result */
224 cpufreq_p4_setdc(policy->cpu, DC_DISABLE);
225 recalibrate_cpu_khz();
226 }
227 /* get max frequency */
228 stock_freq = cpufreq_p4_get_frequency(c);
229 if (!stock_freq)
230 return -EINVAL;
231
232 /* table init */
233 for (i = 1; (p4clockmod_table[i].frequency != CPUFREQ_TABLE_END); i++) {
234 if ((i < 2) && (has_N44_O17_errata[policy->cpu]))
235 p4clockmod_table[i].frequency = CPUFREQ_ENTRY_INVALID;
236 else
237 p4clockmod_table[i].frequency = (stock_freq * i)/8;
238 }
239 cpufreq_frequency_table_get_attr(p4clockmod_table, policy->cpu);
240
241 /* cpuinfo and default policy values */
242
243 /* the transition latency is set to be 1 higher than the maximum
244 * transition latency of the ondemand governor */
245 policy->cpuinfo.transition_latency = 10000001;
246 policy->cur = stock_freq;
247
248 return cpufreq_frequency_table_cpuinfo(policy, &p4clockmod_table[0]);
249}
250
251
252static int cpufreq_p4_cpu_exit(struct cpufreq_policy *policy)
253{
254 cpufreq_frequency_table_put_attr(policy->cpu);
255 return 0;
256}
257
258static unsigned int cpufreq_p4_get(unsigned int cpu)
259{
260 u32 l, h;
261
262 rdmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, &l, &h);
263
264 if (l & 0x10) {
265 l = l >> 1;
266 l &= 0x7;
267 } else
268 l = DC_DISABLE;
269
270 if (l != DC_DISABLE)
271 return stock_freq * l / 8;
272
273 return stock_freq;
274}
275
276static struct freq_attr *p4clockmod_attr[] = {
277 &cpufreq_freq_attr_scaling_available_freqs,
278 NULL,
279};
280
281static struct cpufreq_driver p4clockmod_driver = {
282 .verify = cpufreq_p4_verify,
283 .target = cpufreq_p4_target,
284 .init = cpufreq_p4_cpu_init,
285 .exit = cpufreq_p4_cpu_exit,
286 .get = cpufreq_p4_get,
287 .name = "p4-clockmod",
288 .owner = THIS_MODULE,
289 .attr = p4clockmod_attr,
290};
291
292
293static int __init cpufreq_p4_init(void)
294{
295 struct cpuinfo_x86 *c = &cpu_data(0);
296 int ret;
297
298 /*
299 * THERM_CONTROL is architectural for IA32 now, so
300 * we can rely on the capability checks
301 */
302 if (c->x86_vendor != X86_VENDOR_INTEL)
303 return -ENODEV;
304
305 if (!test_cpu_cap(c, X86_FEATURE_ACPI) ||
306 !test_cpu_cap(c, X86_FEATURE_ACC))
307 return -ENODEV;
308
309 ret = cpufreq_register_driver(&p4clockmod_driver);
310 if (!ret)
311 printk(KERN_INFO PFX "P4/Xeon(TM) CPU On-Demand Clock "
312 "Modulation available\n");
313
314 return ret;
315}
316
317
318static void __exit cpufreq_p4_exit(void)
319{
320 cpufreq_unregister_driver(&p4clockmod_driver);
321}
322
323
324MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>");
325MODULE_DESCRIPTION("cpufreq driver for Pentium(TM) 4/Xeon(TM)");
326MODULE_LICENSE("GPL");
327
328late_initcall(cpufreq_p4_init);
329module_exit(cpufreq_p4_exit);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Pentium 4/Xeon CPU on demand clock modulation/speed scaling
4 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
5 * (C) 2002 Zwane Mwaikambo <zwane@commfireservices.com>
6 * (C) 2002 Arjan van de Ven <arjanv@redhat.com>
7 * (C) 2002 Tora T. Engstad
8 * All Rights Reserved
9 *
10 * The author(s) of this software shall not be held liable for damages
11 * of any nature resulting due to the use of this software. This
12 * software is provided AS-IS with no warranties.
13 *
14 * Date Errata Description
15 * 20020525 N44, O17 12.5% or 25% DC causes lockup
16 */
17
18#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19
20#include <linux/kernel.h>
21#include <linux/module.h>
22#include <linux/init.h>
23#include <linux/smp.h>
24#include <linux/cpufreq.h>
25#include <linux/cpumask.h>
26#include <linux/timex.h>
27
28#include <asm/processor.h>
29#include <asm/msr.h>
30#include <asm/timer.h>
31#include <asm/cpu_device_id.h>
32
33#include "speedstep-lib.h"
34
35/*
36 * Duty Cycle (3bits), note DC_DISABLE is not specified in
37 * intel docs i just use it to mean disable
38 */
39enum {
40 DC_RESV, DC_DFLT, DC_25PT, DC_38PT, DC_50PT,
41 DC_64PT, DC_75PT, DC_88PT, DC_DISABLE
42};
43
44#define DC_ENTRIES 8
45
46
47static int has_N44_O17_errata[NR_CPUS];
48static unsigned int stock_freq;
49static struct cpufreq_driver p4clockmod_driver;
50static unsigned int cpufreq_p4_get(unsigned int cpu);
51
52static int cpufreq_p4_setdc(unsigned int cpu, unsigned int newstate)
53{
54 u32 l, h;
55
56 if ((newstate > DC_DISABLE) || (newstate == DC_RESV))
57 return -EINVAL;
58
59 rdmsr_on_cpu(cpu, MSR_IA32_THERM_STATUS, &l, &h);
60
61 if (l & 0x01)
62 pr_debug("CPU#%d currently thermal throttled\n", cpu);
63
64 if (has_N44_O17_errata[cpu] &&
65 (newstate == DC_25PT || newstate == DC_DFLT))
66 newstate = DC_38PT;
67
68 rdmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, &l, &h);
69 if (newstate == DC_DISABLE) {
70 pr_debug("CPU#%d disabling modulation\n", cpu);
71 wrmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, l & ~(1<<4), h);
72 } else {
73 pr_debug("CPU#%d setting duty cycle to %d%%\n",
74 cpu, ((125 * newstate) / 10));
75 /* bits 63 - 5 : reserved
76 * bit 4 : enable/disable
77 * bits 3-1 : duty cycle
78 * bit 0 : reserved
79 */
80 l = (l & ~14);
81 l = l | (1<<4) | ((newstate & 0x7)<<1);
82 wrmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, l, h);
83 }
84
85 return 0;
86}
87
88
89static struct cpufreq_frequency_table p4clockmod_table[] = {
90 {0, DC_RESV, CPUFREQ_ENTRY_INVALID},
91 {0, DC_DFLT, 0},
92 {0, DC_25PT, 0},
93 {0, DC_38PT, 0},
94 {0, DC_50PT, 0},
95 {0, DC_64PT, 0},
96 {0, DC_75PT, 0},
97 {0, DC_88PT, 0},
98 {0, DC_DISABLE, 0},
99 {0, DC_RESV, CPUFREQ_TABLE_END},
100};
101
102
103static int cpufreq_p4_target(struct cpufreq_policy *policy, unsigned int index)
104{
105 int i;
106
107 /* run on each logical CPU,
108 * see section 13.15.3 of IA32 Intel Architecture Software
109 * Developer's Manual, Volume 3
110 */
111 for_each_cpu(i, policy->cpus)
112 cpufreq_p4_setdc(i, p4clockmod_table[index].driver_data);
113
114 return 0;
115}
116
117
118static unsigned int cpufreq_p4_get_frequency(struct cpuinfo_x86 *c)
119{
120 if (c->x86 == 0x06) {
121 if (cpu_has(c, X86_FEATURE_EST))
122 pr_warn_once("Warning: EST-capable CPU detected. The acpi-cpufreq module offers voltage scaling in addition to frequency scaling. You should use that instead of p4-clockmod, if possible.\n");
123 switch (c->x86_model) {
124 case 0x0E: /* Core */
125 case 0x0F: /* Core Duo */
126 case 0x16: /* Celeron Core */
127 case 0x1C: /* Atom */
128 p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
129 return speedstep_get_frequency(SPEEDSTEP_CPU_PCORE);
130 case 0x0D: /* Pentium M (Dothan) */
131 p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
132 fallthrough;
133 case 0x09: /* Pentium M (Banias) */
134 return speedstep_get_frequency(SPEEDSTEP_CPU_PM);
135 }
136 }
137
138 if (c->x86 != 0xF)
139 return 0;
140
141 /* on P-4s, the TSC runs with constant frequency independent whether
142 * throttling is active or not. */
143 p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
144
145 if (speedstep_detect_processor() == SPEEDSTEP_CPU_P4M) {
146 pr_warn("Warning: Pentium 4-M detected. The speedstep-ich or acpi cpufreq modules offer voltage scaling in addition of frequency scaling. You should use either one instead of p4-clockmod, if possible.\n");
147 return speedstep_get_frequency(SPEEDSTEP_CPU_P4M);
148 }
149
150 return speedstep_get_frequency(SPEEDSTEP_CPU_P4D);
151}
152
153
154
155static int cpufreq_p4_cpu_init(struct cpufreq_policy *policy)
156{
157 struct cpuinfo_x86 *c = &cpu_data(policy->cpu);
158 int cpuid = 0;
159 unsigned int i;
160
161#ifdef CONFIG_SMP
162 cpumask_copy(policy->cpus, topology_sibling_cpumask(policy->cpu));
163#endif
164
165 /* Errata workaround */
166 cpuid = (c->x86 << 8) | (c->x86_model << 4) | c->x86_stepping;
167 switch (cpuid) {
168 case 0x0f07:
169 case 0x0f0a:
170 case 0x0f11:
171 case 0x0f12:
172 has_N44_O17_errata[policy->cpu] = 1;
173 pr_debug("has errata -- disabling low frequencies\n");
174 }
175
176 if (speedstep_detect_processor() == SPEEDSTEP_CPU_P4D &&
177 c->x86_model < 2) {
178 /* switch to maximum frequency and measure result */
179 cpufreq_p4_setdc(policy->cpu, DC_DISABLE);
180 recalibrate_cpu_khz();
181 }
182 /* get max frequency */
183 stock_freq = cpufreq_p4_get_frequency(c);
184 if (!stock_freq)
185 return -EINVAL;
186
187 /* table init */
188 for (i = 1; (p4clockmod_table[i].frequency != CPUFREQ_TABLE_END); i++) {
189 if ((i < 2) && (has_N44_O17_errata[policy->cpu]))
190 p4clockmod_table[i].frequency = CPUFREQ_ENTRY_INVALID;
191 else
192 p4clockmod_table[i].frequency = (stock_freq * i)/8;
193 }
194
195 /* cpuinfo and default policy values */
196
197 /* the transition latency is set to be 1 higher than the maximum
198 * transition latency of the ondemand governor */
199 policy->cpuinfo.transition_latency = 10000001;
200 policy->freq_table = &p4clockmod_table[0];
201
202 return 0;
203}
204
205
206static unsigned int cpufreq_p4_get(unsigned int cpu)
207{
208 u32 l, h;
209
210 rdmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, &l, &h);
211
212 if (l & 0x10) {
213 l = l >> 1;
214 l &= 0x7;
215 } else
216 l = DC_DISABLE;
217
218 if (l != DC_DISABLE)
219 return stock_freq * l / 8;
220
221 return stock_freq;
222}
223
224static struct cpufreq_driver p4clockmod_driver = {
225 .verify = cpufreq_generic_frequency_table_verify,
226 .target_index = cpufreq_p4_target,
227 .init = cpufreq_p4_cpu_init,
228 .get = cpufreq_p4_get,
229 .name = "p4-clockmod",
230 .attr = cpufreq_generic_attr,
231};
232
233static const struct x86_cpu_id cpufreq_p4_id[] = {
234 X86_MATCH_VENDOR_FEATURE(INTEL, X86_FEATURE_ACC, NULL),
235 {}
236};
237
238/*
239 * Intentionally no MODULE_DEVICE_TABLE here: this driver should not
240 * be auto loaded. Please don't add one.
241 */
242
243static int __init cpufreq_p4_init(void)
244{
245 int ret;
246
247 /*
248 * THERM_CONTROL is architectural for IA32 now, so
249 * we can rely on the capability checks
250 */
251 if (!x86_match_cpu(cpufreq_p4_id) || !boot_cpu_has(X86_FEATURE_ACPI))
252 return -ENODEV;
253
254 ret = cpufreq_register_driver(&p4clockmod_driver);
255 if (!ret)
256 pr_info("P4/Xeon(TM) CPU On-Demand Clock Modulation available\n");
257
258 return ret;
259}
260
261
262static void __exit cpufreq_p4_exit(void)
263{
264 cpufreq_unregister_driver(&p4clockmod_driver);
265}
266
267
268MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>");
269MODULE_DESCRIPTION("cpufreq driver for Pentium(TM) 4/Xeon(TM)");
270MODULE_LICENSE("GPL");
271
272late_initcall(cpufreq_p4_init);
273module_exit(cpufreq_p4_exit);