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[net-next-2.6.git] / arch / x86 / kernel / cpu / cpufreq / p4-clockmod.c
CommitLineData
1da177e4
LT
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.
32ee8c3e 17 *
1da177e4
LT
18 * Date Errata Description
19 * 20020525 N44, O17 12.5% or 25% DC causes lockup
20 *
21 */
22
1da177e4 23#include <linux/kernel.h>
32ee8c3e 24#include <linux/module.h>
1da177e4
LT
25#include <linux/init.h>
26#include <linux/smp.h>
27#include <linux/cpufreq.h>
1da177e4 28#include <linux/cpumask.h>
bbfebd66 29#include <linux/timex.h>
1da177e4 30
32ee8c3e 31#include <asm/processor.h>
1da177e4 32#include <asm/msr.h>
199785ea 33#include <asm/timer.h>
1da177e4
LT
34
35#include "speedstep-lib.h"
36
37#define PFX "p4-clockmod: "
bbfebd66
DJ
38#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, \
39 "p4-clockmod", msg)
1da177e4
LT
40
41/*
42 * Duty Cycle (3bits), note DC_DISABLE is not specified in
43 * intel docs i just use it to mean disable
44 */
45enum {
46 DC_RESV, DC_DFLT, DC_25PT, DC_38PT, DC_50PT,
47 DC_64PT, DC_75PT, DC_88PT, DC_DISABLE
48};
49
50#define DC_ENTRIES 8
51
52
53static int has_N44_O17_errata[NR_CPUS];
54static unsigned int stock_freq;
55static struct cpufreq_driver p4clockmod_driver;
56static unsigned int cpufreq_p4_get(unsigned int cpu);
57
58static int cpufreq_p4_setdc(unsigned int cpu, unsigned int newstate)
59{
60 u32 l, h;
61
bbfebd66
DJ
62 if (!cpu_online(cpu) ||
63 (newstate > DC_DISABLE) || (newstate == DC_RESV))
1da177e4
LT
64 return -EINVAL;
65
551948bc 66 rdmsr_on_cpu(cpu, MSR_IA32_THERM_STATUS, &l, &h);
1da177e4
LT
67
68 if (l & 0x01)
69 dprintk("CPU#%d currently thermal throttled\n", cpu);
70
bbfebd66
DJ
71 if (has_N44_O17_errata[cpu] &&
72 (newstate == DC_25PT || newstate == DC_DFLT))
1da177e4
LT
73 newstate = DC_38PT;
74
551948bc 75 rdmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, &l, &h);
1da177e4
LT
76 if (newstate == DC_DISABLE) {
77 dprintk("CPU#%d disabling modulation\n", cpu);
551948bc 78 wrmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, l & ~(1<<4), h);
1da177e4
LT
79 } else {
80 dprintk("CPU#%d setting duty cycle to %d%%\n",
81 cpu, ((125 * newstate) / 10));
32ee8c3e 82 /* bits 63 - 5 : reserved
1da177e4
LT
83 * bit 4 : enable/disable
84 * bits 3-1 : duty cycle
85 * bit 0 : reserved
86 */
87 l = (l & ~14);
88 l = l | (1<<4) | ((newstate & 0x7)<<1);
551948bc 89 wrmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, l, h);
1da177e4
LT
90 }
91
92 return 0;
93}
94
95
96static struct cpufreq_frequency_table p4clockmod_table[] = {
97 {DC_RESV, CPUFREQ_ENTRY_INVALID},
98 {DC_DFLT, 0},
99 {DC_25PT, 0},
100 {DC_38PT, 0},
101 {DC_50PT, 0},
102 {DC_64PT, 0},
103 {DC_75PT, 0},
104 {DC_88PT, 0},
105 {DC_DISABLE, 0},
106 {DC_RESV, CPUFREQ_TABLE_END},
107};
108
109
110static int cpufreq_p4_target(struct cpufreq_policy *policy,
111 unsigned int target_freq,
112 unsigned int relation)
113{
114 unsigned int newstate = DC_RESV;
115 struct cpufreq_freqs freqs;
1da177e4
LT
116 int i;
117
bbfebd66
DJ
118 if (cpufreq_frequency_table_target(policy, &p4clockmod_table[0],
119 target_freq, relation, &newstate))
1da177e4
LT
120 return -EINVAL;
121
122 freqs.old = cpufreq_p4_get(policy->cpu);
123 freqs.new = stock_freq * p4clockmod_table[newstate].index / 8;
124
125 if (freqs.new == freqs.old)
126 return 0;
127
128 /* notifiers */
835481d9 129 for_each_cpu(i, policy->cpus) {
1da177e4
LT
130 freqs.cpu = i;
131 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
132 }
133
bbfebd66
DJ
134 /* run on each logical CPU,
135 * see section 13.15.3 of IA32 Intel Architecture Software
32ee8c3e 136 * Developer's Manual, Volume 3
1da177e4 137 */
835481d9 138 for_each_cpu(i, policy->cpus)
1da177e4 139 cpufreq_p4_setdc(i, p4clockmod_table[newstate].index);
1da177e4
LT
140
141 /* notifiers */
835481d9 142 for_each_cpu(i, policy->cpus) {
1da177e4
LT
143 freqs.cpu = i;
144 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
145 }
146
147 return 0;
148}
149
150
151static int cpufreq_p4_verify(struct cpufreq_policy *policy)
152{
153 return cpufreq_frequency_table_verify(policy, &p4clockmod_table[0]);
154}
155
156
157static unsigned int cpufreq_p4_get_frequency(struct cpuinfo_x86 *c)
158{
4e74663c
DB
159 if (c->x86 == 0x06) {
160 if (cpu_has(c, X86_FEATURE_EST))
bbfebd66
DJ
161 printk(KERN_WARNING PFX "Warning: EST-capable CPU "
162 "detected. The acpi-cpufreq module offers "
163 "voltage scaling in addition of frequency "
164 "scaling. You should use that instead of "
165 "p4-clockmod, if possible.\n");
4e74663c
DB
166 switch (c->x86_model) {
167 case 0x0E: /* Core */
168 case 0x0F: /* Core Duo */
8529154e 169 case 0x16: /* Celeron Core */
43195037 170 case 0x1C: /* Atom */
4e74663c 171 p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
bbfebd66 172 return speedstep_get_frequency(SPEEDSTEP_CPU_PCORE);
4e74663c
DB
173 case 0x0D: /* Pentium M (Dothan) */
174 p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
175 /* fall through */
176 case 0x09: /* Pentium M (Banias) */
bbfebd66 177 return speedstep_get_frequency(SPEEDSTEP_CPU_PM);
4e74663c 178 }
1da177e4
LT
179 }
180
181 if (c->x86 != 0xF) {
10db2e5c 182 if (!cpu_has(c, X86_FEATURE_EST))
bbfebd66
DJ
183 printk(KERN_WARNING PFX "Unknown CPU. "
184 "Please send an e-mail to "
185 "<cpufreq@vger.kernel.org>\n");
1da177e4
LT
186 return 0;
187 }
188
189 /* on P-4s, the TSC runs with constant frequency independent whether
190 * throttling is active or not. */
191 p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
192
bbfebd66 193 if (speedstep_detect_processor() == SPEEDSTEP_CPU_P4M) {
1da177e4
LT
194 printk(KERN_WARNING PFX "Warning: Pentium 4-M detected. "
195 "The speedstep-ich or acpi cpufreq modules offer "
196 "voltage scaling in addition of frequency scaling. "
197 "You should use either one instead of p4-clockmod, "
198 "if possible.\n");
bbfebd66 199 return speedstep_get_frequency(SPEEDSTEP_CPU_P4M);
1da177e4
LT
200 }
201
bbfebd66 202 return speedstep_get_frequency(SPEEDSTEP_CPU_P4D);
1da177e4
LT
203}
204
32ee8c3e 205
1da177e4
LT
206
207static int cpufreq_p4_cpu_init(struct cpufreq_policy *policy)
208{
92cb7612 209 struct cpuinfo_x86 *c = &cpu_data(policy->cpu);
1da177e4
LT
210 int cpuid = 0;
211 unsigned int i;
212
213#ifdef CONFIG_SMP
7ad728f9 214 cpumask_copy(policy->cpus, cpu_sibling_mask(policy->cpu));
1da177e4
LT
215#endif
216
217 /* Errata workaround */
218 cpuid = (c->x86 << 8) | (c->x86_model << 4) | c->x86_mask;
219 switch (cpuid) {
220 case 0x0f07:
221 case 0x0f0a:
222 case 0x0f11:
223 case 0x0f12:
224 has_N44_O17_errata[policy->cpu] = 1;
225 dprintk("has errata -- disabling low frequencies\n");
226 }
32ee8c3e 227
199785ea
MCO
228 if (speedstep_detect_processor() == SPEEDSTEP_CPU_P4D &&
229 c->x86_model < 2) {
230 /* switch to maximum frequency and measure result */
231 cpufreq_p4_setdc(policy->cpu, DC_DISABLE);
232 recalibrate_cpu_khz();
233 }
1da177e4
LT
234 /* get max frequency */
235 stock_freq = cpufreq_p4_get_frequency(c);
236 if (!stock_freq)
237 return -EINVAL;
238
239 /* table init */
bbfebd66
DJ
240 for (i = 1; (p4clockmod_table[i].frequency != CPUFREQ_TABLE_END); i++) {
241 if ((i < 2) && (has_N44_O17_errata[policy->cpu]))
1da177e4
LT
242 p4clockmod_table[i].frequency = CPUFREQ_ENTRY_INVALID;
243 else
244 p4clockmod_table[i].frequency = (stock_freq * i)/8;
245 }
246 cpufreq_frequency_table_get_attr(p4clockmod_table, policy->cpu);
32ee8c3e 247
1da177e4 248 /* cpuinfo and default policy values */
36e8abf3
DJ
249
250 /* the transition latency is set to be 1 higher than the maximum
251 * transition latency of the ondemand governor */
252 policy->cpuinfo.transition_latency = 10000001;
1da177e4
LT
253 policy->cur = stock_freq;
254
255 return cpufreq_frequency_table_cpuinfo(policy, &p4clockmod_table[0]);
256}
257
258
259static int cpufreq_p4_cpu_exit(struct cpufreq_policy *policy)
260{
32ee8c3e 261 cpufreq_frequency_table_put_attr(policy->cpu);
1da177e4
LT
262 return 0;
263}
264
265static unsigned int cpufreq_p4_get(unsigned int cpu)
266{
1da177e4
LT
267 u32 l, h;
268
551948bc 269 rdmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, &l, &h);
1da177e4
LT
270
271 if (l & 0x10) {
272 l = l >> 1;
273 l &= 0x7;
274 } else
275 l = DC_DISABLE;
276
277 if (l != DC_DISABLE)
bbfebd66 278 return stock_freq * l / 8;
1da177e4
LT
279
280 return stock_freq;
281}
282
bbfebd66 283static struct freq_attr *p4clockmod_attr[] = {
1da177e4
LT
284 &cpufreq_freq_attr_scaling_available_freqs,
285 NULL,
286};
287
288static struct cpufreq_driver p4clockmod_driver = {
32ee8c3e 289 .verify = cpufreq_p4_verify,
1da177e4
LT
290 .target = cpufreq_p4_target,
291 .init = cpufreq_p4_cpu_init,
292 .exit = cpufreq_p4_cpu_exit,
293 .get = cpufreq_p4_get,
294 .name = "p4-clockmod",
295 .owner = THIS_MODULE,
296 .attr = p4clockmod_attr,
297};
298
299
300static int __init cpufreq_p4_init(void)
32ee8c3e 301{
92cb7612 302 struct cpuinfo_x86 *c = &cpu_data(0);
1da177e4
LT
303 int ret;
304
305 /*
32ee8c3e 306 * THERM_CONTROL is architectural for IA32 now, so
1da177e4
LT
307 * we can rely on the capability checks
308 */
309 if (c->x86_vendor != X86_VENDOR_INTEL)
310 return -ENODEV;
311
8ce116e5
IM
312 if (!test_cpu_cap(c, X86_FEATURE_ACPI) ||
313 !test_cpu_cap(c, X86_FEATURE_ACC))
1da177e4
LT
314 return -ENODEV;
315
316 ret = cpufreq_register_driver(&p4clockmod_driver);
317 if (!ret)
bbfebd66
DJ
318 printk(KERN_INFO PFX "P4/Xeon(TM) CPU On-Demand Clock "
319 "Modulation available\n");
1da177e4 320
bbfebd66 321 return ret;
1da177e4
LT
322}
323
324
325static void __exit cpufreq_p4_exit(void)
326{
327 cpufreq_unregister_driver(&p4clockmod_driver);
328}
329
330
bbfebd66
DJ
331MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>");
332MODULE_DESCRIPTION("cpufreq driver for Pentium(TM) 4/Xeon(TM)");
333MODULE_LICENSE("GPL");
1da177e4
LT
334
335late_initcall(cpufreq_p4_init);
336module_exit(cpufreq_p4_exit);