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1/*
2 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
3 *
4 * Licensed under the terms of the GNU GPL License version 2.
5 *
6 * BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
7 */
8
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/init.h>
12#include <linux/cpufreq.h>
13#include <linux/timex.h>
14
15#include <asm/msr.h>
16#include <asm/processor.h>
17
18static struct cpufreq_driver longrun_driver;
19
20/**
21 * longrun_{low,high}_freq is needed for the conversion of cpufreq kHz
22 * values into per cent values. In TMTA microcode, the following is valid:
23 * performance_pctg = (current_freq - low_freq)/(high_freq - low_freq)
24 */
25static unsigned int longrun_low_freq, longrun_high_freq;
26
27
28/**
29 * longrun_get_policy - get the current LongRun policy
30 * @policy: struct cpufreq_policy where current policy is written into
31 *
32 * Reads the current LongRun policy by access to MSR_TMTA_LONGRUN_FLAGS
33 * and MSR_TMTA_LONGRUN_CTRL
34 */
35static void __cpuinit longrun_get_policy(struct cpufreq_policy *policy)
36{
37 u32 msr_lo, msr_hi;
38
39 rdmsr(MSR_TMTA_LONGRUN_FLAGS, msr_lo, msr_hi);
40 pr_debug("longrun flags are %x - %x\n", msr_lo, msr_hi);
41 if (msr_lo & 0x01)
42 policy->policy = CPUFREQ_POLICY_PERFORMANCE;
43 else
44 policy->policy = CPUFREQ_POLICY_POWERSAVE;
45
46 rdmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi);
47 pr_debug("longrun ctrl is %x - %x\n", msr_lo, msr_hi);
48 msr_lo &= 0x0000007F;
49 msr_hi &= 0x0000007F;
50
51 if (longrun_high_freq <= longrun_low_freq) {
52 /* Assume degenerate Longrun table */
53 policy->min = policy->max = longrun_high_freq;
54 } else {
55 policy->min = longrun_low_freq + msr_lo *
56 ((longrun_high_freq - longrun_low_freq) / 100);
57 policy->max = longrun_low_freq + msr_hi *
58 ((longrun_high_freq - longrun_low_freq) / 100);
59 }
60 policy->cpu = 0;
61}
62
63
64/**
65 * longrun_set_policy - sets a new CPUFreq policy
66 * @policy: new policy
67 *
68 * Sets a new CPUFreq policy on LongRun-capable processors. This function
69 * has to be called with cpufreq_driver locked.
70 */
71static int longrun_set_policy(struct cpufreq_policy *policy)
72{
73 u32 msr_lo, msr_hi;
74 u32 pctg_lo, pctg_hi;
75
76 if (!policy)
77 return -EINVAL;
78
79 if (longrun_high_freq <= longrun_low_freq) {
80 /* Assume degenerate Longrun table */
81 pctg_lo = pctg_hi = 100;
82 } else {
83 pctg_lo = (policy->min - longrun_low_freq) /
84 ((longrun_high_freq - longrun_low_freq) / 100);
85 pctg_hi = (policy->max - longrun_low_freq) /
86 ((longrun_high_freq - longrun_low_freq) / 100);
87 }
88
89 if (pctg_hi > 100)
90 pctg_hi = 100;
91 if (pctg_lo > pctg_hi)
92 pctg_lo = pctg_hi;
93
94 /* performance or economy mode */
95 rdmsr(MSR_TMTA_LONGRUN_FLAGS, msr_lo, msr_hi);
96 msr_lo &= 0xFFFFFFFE;
97 switch (policy->policy) {
98 case CPUFREQ_POLICY_PERFORMANCE:
99 msr_lo |= 0x00000001;
100 break;
101 case CPUFREQ_POLICY_POWERSAVE:
102 break;
103 }
104 wrmsr(MSR_TMTA_LONGRUN_FLAGS, msr_lo, msr_hi);
105
106 /* lower and upper boundary */
107 rdmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi);
108 msr_lo &= 0xFFFFFF80;
109 msr_hi &= 0xFFFFFF80;
110 msr_lo |= pctg_lo;
111 msr_hi |= pctg_hi;
112 wrmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi);
113
114 return 0;
115}
116
117
118/**
119 * longrun_verify_poliy - verifies a new CPUFreq policy
120 * @policy: the policy to verify
121 *
122 * Validates a new CPUFreq policy. This function has to be called with
123 * cpufreq_driver locked.
124 */
125static int longrun_verify_policy(struct cpufreq_policy *policy)
126{
127 if (!policy)
128 return -EINVAL;
129
130 policy->cpu = 0;
131 cpufreq_verify_within_limits(policy,
132 policy->cpuinfo.min_freq,
133 policy->cpuinfo.max_freq);
134
135 if ((policy->policy != CPUFREQ_POLICY_POWERSAVE) &&
136 (policy->policy != CPUFREQ_POLICY_PERFORMANCE))
137 return -EINVAL;
138
139 return 0;
140}
141
142static unsigned int longrun_get(unsigned int cpu)
143{
144 u32 eax, ebx, ecx, edx;
145
146 if (cpu)
147 return 0;
148
149 cpuid(0x80860007, &eax, &ebx, &ecx, &edx);
150 pr_debug("cpuid eax is %u\n", eax);
151
152 return eax * 1000;
153}
154
155/**
156 * longrun_determine_freqs - determines the lowest and highest possible core frequency
157 * @low_freq: an int to put the lowest frequency into
158 * @high_freq: an int to put the highest frequency into
159 *
160 * Determines the lowest and highest possible core frequencies on this CPU.
161 * This is necessary to calculate the performance percentage according to
162 * TMTA rules:
163 * performance_pctg = (target_freq - low_freq)/(high_freq - low_freq)
164 */
165static int __cpuinit longrun_determine_freqs(unsigned int *low_freq,
166 unsigned int *high_freq)
167{
168 u32 msr_lo, msr_hi;
169 u32 save_lo, save_hi;
170 u32 eax, ebx, ecx, edx;
171 u32 try_hi;
172 struct cpuinfo_x86 *c = &cpu_data(0);
173
174 if (!low_freq || !high_freq)
175 return -EINVAL;
176
177 if (cpu_has(c, X86_FEATURE_LRTI)) {
178 /* if the LongRun Table Interface is present, the
179 * detection is a bit easier:
180 * For minimum frequency, read out the maximum
181 * level (msr_hi), write that into "currently
182 * selected level", and read out the frequency.
183 * For maximum frequency, read out level zero.
184 */
185 /* minimum */
186 rdmsr(MSR_TMTA_LRTI_READOUT, msr_lo, msr_hi);
187 wrmsr(MSR_TMTA_LRTI_READOUT, msr_hi, msr_hi);
188 rdmsr(MSR_TMTA_LRTI_VOLT_MHZ, msr_lo, msr_hi);
189 *low_freq = msr_lo * 1000; /* to kHz */
190
191 /* maximum */
192 wrmsr(MSR_TMTA_LRTI_READOUT, 0, msr_hi);
193 rdmsr(MSR_TMTA_LRTI_VOLT_MHZ, msr_lo, msr_hi);
194 *high_freq = msr_lo * 1000; /* to kHz */
195
196 pr_debug("longrun table interface told %u - %u kHz\n",
197 *low_freq, *high_freq);
198
199 if (*low_freq > *high_freq)
200 *low_freq = *high_freq;
201 return 0;
202 }
203
204 /* set the upper border to the value determined during TSC init */
205 *high_freq = (cpu_khz / 1000);
206 *high_freq = *high_freq * 1000;
207 pr_debug("high frequency is %u kHz\n", *high_freq);
208
209 /* get current borders */
210 rdmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi);
211 save_lo = msr_lo & 0x0000007F;
212 save_hi = msr_hi & 0x0000007F;
213
214 /* if current perf_pctg is larger than 90%, we need to decrease the
215 * upper limit to make the calculation more accurate.
216 */
217 cpuid(0x80860007, &eax, &ebx, &ecx, &edx);
218 /* try decreasing in 10% steps, some processors react only
219 * on some barrier values */
220 for (try_hi = 80; try_hi > 0 && ecx > 90; try_hi -= 10) {
221 /* set to 0 to try_hi perf_pctg */
222 msr_lo &= 0xFFFFFF80;
223 msr_hi &= 0xFFFFFF80;
224 msr_hi |= try_hi;
225 wrmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi);
226
227 /* read out current core MHz and current perf_pctg */
228 cpuid(0x80860007, &eax, &ebx, &ecx, &edx);
229
230 /* restore values */
231 wrmsr(MSR_TMTA_LONGRUN_CTRL, save_lo, save_hi);
232 }
233 pr_debug("percentage is %u %%, freq is %u MHz\n", ecx, eax);
234
235 /* performance_pctg = (current_freq - low_freq)/(high_freq - low_freq)
236 * eqals
237 * low_freq * (1 - perf_pctg) = (cur_freq - high_freq * perf_pctg)
238 *
239 * high_freq * perf_pctg is stored tempoarily into "ebx".
240 */
241 ebx = (((cpu_khz / 1000) * ecx) / 100); /* to MHz */
242
243 if ((ecx > 95) || (ecx == 0) || (eax < ebx))
244 return -EIO;
245
246 edx = ((eax - ebx) * 100) / (100 - ecx);
247 *low_freq = edx * 1000; /* back to kHz */
248
249 pr_debug("low frequency is %u kHz\n", *low_freq);
250
251 if (*low_freq > *high_freq)
252 *low_freq = *high_freq;
253
254 return 0;
255}
256
257
258static int __cpuinit longrun_cpu_init(struct cpufreq_policy *policy)
259{
260 int result = 0;
261
262 /* capability check */
263 if (policy->cpu != 0)
264 return -ENODEV;
265
266 /* detect low and high frequency */
267 result = longrun_determine_freqs(&longrun_low_freq, &longrun_high_freq);
268 if (result)
269 return result;
270
271 /* cpuinfo and default policy values */
272 policy->cpuinfo.min_freq = longrun_low_freq;
273 policy->cpuinfo.max_freq = longrun_high_freq;
274 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
275 longrun_get_policy(policy);
276
277 return 0;
278}
279
280
281static struct cpufreq_driver longrun_driver = {
282 .flags = CPUFREQ_CONST_LOOPS,
283 .verify = longrun_verify_policy,
284 .setpolicy = longrun_set_policy,
285 .get = longrun_get,
286 .init = longrun_cpu_init,
287 .name = "longrun",
288 .owner = THIS_MODULE,
289};
290
291
292/**
293 * longrun_init - initializes the Transmeta Crusoe LongRun CPUFreq driver
294 *
295 * Initializes the LongRun support.
296 */
297static int __init longrun_init(void)
298{
299 struct cpuinfo_x86 *c = &cpu_data(0);
300
301 if (c->x86_vendor != X86_VENDOR_TRANSMETA ||
302 !cpu_has(c, X86_FEATURE_LONGRUN))
303 return -ENODEV;
304
305 return cpufreq_register_driver(&longrun_driver);
306}
307
308
309/**
310 * longrun_exit - unregisters LongRun support
311 */
312static void __exit longrun_exit(void)
313{
314 cpufreq_unregister_driver(&longrun_driver);
315}
316
317
318MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>");
319MODULE_DESCRIPTION("LongRun driver for Transmeta Crusoe and "
320 "Efficeon processors.");
321MODULE_LICENSE("GPL");
322
323module_init(longrun_init);
324module_exit(longrun_exit);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
4 *
5 * BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
6 */
7
8#include <linux/kernel.h>
9#include <linux/module.h>
10#include <linux/init.h>
11#include <linux/cpufreq.h>
12#include <linux/timex.h>
13
14#include <asm/msr.h>
15#include <asm/processor.h>
16#include <asm/cpu_device_id.h>
17
18static struct cpufreq_driver longrun_driver;
19
20/**
21 * longrun_{low,high}_freq is needed for the conversion of cpufreq kHz
22 * values into per cent values. In TMTA microcode, the following is valid:
23 * performance_pctg = (current_freq - low_freq)/(high_freq - low_freq)
24 */
25static unsigned int longrun_low_freq, longrun_high_freq;
26
27
28/**
29 * longrun_get_policy - get the current LongRun policy
30 * @policy: struct cpufreq_policy where current policy is written into
31 *
32 * Reads the current LongRun policy by access to MSR_TMTA_LONGRUN_FLAGS
33 * and MSR_TMTA_LONGRUN_CTRL
34 */
35static void longrun_get_policy(struct cpufreq_policy *policy)
36{
37 u32 msr_lo, msr_hi;
38
39 rdmsr(MSR_TMTA_LONGRUN_FLAGS, msr_lo, msr_hi);
40 pr_debug("longrun flags are %x - %x\n", msr_lo, msr_hi);
41 if (msr_lo & 0x01)
42 policy->policy = CPUFREQ_POLICY_PERFORMANCE;
43 else
44 policy->policy = CPUFREQ_POLICY_POWERSAVE;
45
46 rdmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi);
47 pr_debug("longrun ctrl is %x - %x\n", msr_lo, msr_hi);
48 msr_lo &= 0x0000007F;
49 msr_hi &= 0x0000007F;
50
51 if (longrun_high_freq <= longrun_low_freq) {
52 /* Assume degenerate Longrun table */
53 policy->min = policy->max = longrun_high_freq;
54 } else {
55 policy->min = longrun_low_freq + msr_lo *
56 ((longrun_high_freq - longrun_low_freq) / 100);
57 policy->max = longrun_low_freq + msr_hi *
58 ((longrun_high_freq - longrun_low_freq) / 100);
59 }
60 policy->cpu = 0;
61}
62
63
64/**
65 * longrun_set_policy - sets a new CPUFreq policy
66 * @policy: new policy
67 *
68 * Sets a new CPUFreq policy on LongRun-capable processors. This function
69 * has to be called with cpufreq_driver locked.
70 */
71static int longrun_set_policy(struct cpufreq_policy *policy)
72{
73 u32 msr_lo, msr_hi;
74 u32 pctg_lo, pctg_hi;
75
76 if (!policy)
77 return -EINVAL;
78
79 if (longrun_high_freq <= longrun_low_freq) {
80 /* Assume degenerate Longrun table */
81 pctg_lo = pctg_hi = 100;
82 } else {
83 pctg_lo = (policy->min - longrun_low_freq) /
84 ((longrun_high_freq - longrun_low_freq) / 100);
85 pctg_hi = (policy->max - longrun_low_freq) /
86 ((longrun_high_freq - longrun_low_freq) / 100);
87 }
88
89 if (pctg_hi > 100)
90 pctg_hi = 100;
91 if (pctg_lo > pctg_hi)
92 pctg_lo = pctg_hi;
93
94 /* performance or economy mode */
95 rdmsr(MSR_TMTA_LONGRUN_FLAGS, msr_lo, msr_hi);
96 msr_lo &= 0xFFFFFFFE;
97 switch (policy->policy) {
98 case CPUFREQ_POLICY_PERFORMANCE:
99 msr_lo |= 0x00000001;
100 break;
101 case CPUFREQ_POLICY_POWERSAVE:
102 break;
103 }
104 wrmsr(MSR_TMTA_LONGRUN_FLAGS, msr_lo, msr_hi);
105
106 /* lower and upper boundary */
107 rdmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi);
108 msr_lo &= 0xFFFFFF80;
109 msr_hi &= 0xFFFFFF80;
110 msr_lo |= pctg_lo;
111 msr_hi |= pctg_hi;
112 wrmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi);
113
114 return 0;
115}
116
117
118/**
119 * longrun_verify_poliy - verifies a new CPUFreq policy
120 * @policy: the policy to verify
121 *
122 * Validates a new CPUFreq policy. This function has to be called with
123 * cpufreq_driver locked.
124 */
125static int longrun_verify_policy(struct cpufreq_policy_data *policy)
126{
127 if (!policy)
128 return -EINVAL;
129
130 policy->cpu = 0;
131 cpufreq_verify_within_cpu_limits(policy);
132
133 return 0;
134}
135
136static unsigned int longrun_get(unsigned int cpu)
137{
138 u32 eax, ebx, ecx, edx;
139
140 if (cpu)
141 return 0;
142
143 cpuid(0x80860007, &eax, &ebx, &ecx, &edx);
144 pr_debug("cpuid eax is %u\n", eax);
145
146 return eax * 1000;
147}
148
149/**
150 * longrun_determine_freqs - determines the lowest and highest possible core frequency
151 * @low_freq: an int to put the lowest frequency into
152 * @high_freq: an int to put the highest frequency into
153 *
154 * Determines the lowest and highest possible core frequencies on this CPU.
155 * This is necessary to calculate the performance percentage according to
156 * TMTA rules:
157 * performance_pctg = (target_freq - low_freq)/(high_freq - low_freq)
158 */
159static int longrun_determine_freqs(unsigned int *low_freq,
160 unsigned int *high_freq)
161{
162 u32 msr_lo, msr_hi;
163 u32 save_lo, save_hi;
164 u32 eax, ebx, ecx, edx;
165 u32 try_hi;
166 struct cpuinfo_x86 *c = &cpu_data(0);
167
168 if (!low_freq || !high_freq)
169 return -EINVAL;
170
171 if (cpu_has(c, X86_FEATURE_LRTI)) {
172 /* if the LongRun Table Interface is present, the
173 * detection is a bit easier:
174 * For minimum frequency, read out the maximum
175 * level (msr_hi), write that into "currently
176 * selected level", and read out the frequency.
177 * For maximum frequency, read out level zero.
178 */
179 /* minimum */
180 rdmsr(MSR_TMTA_LRTI_READOUT, msr_lo, msr_hi);
181 wrmsr(MSR_TMTA_LRTI_READOUT, msr_hi, msr_hi);
182 rdmsr(MSR_TMTA_LRTI_VOLT_MHZ, msr_lo, msr_hi);
183 *low_freq = msr_lo * 1000; /* to kHz */
184
185 /* maximum */
186 wrmsr(MSR_TMTA_LRTI_READOUT, 0, msr_hi);
187 rdmsr(MSR_TMTA_LRTI_VOLT_MHZ, msr_lo, msr_hi);
188 *high_freq = msr_lo * 1000; /* to kHz */
189
190 pr_debug("longrun table interface told %u - %u kHz\n",
191 *low_freq, *high_freq);
192
193 if (*low_freq > *high_freq)
194 *low_freq = *high_freq;
195 return 0;
196 }
197
198 /* set the upper border to the value determined during TSC init */
199 *high_freq = (cpu_khz / 1000);
200 *high_freq = *high_freq * 1000;
201 pr_debug("high frequency is %u kHz\n", *high_freq);
202
203 /* get current borders */
204 rdmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi);
205 save_lo = msr_lo & 0x0000007F;
206 save_hi = msr_hi & 0x0000007F;
207
208 /* if current perf_pctg is larger than 90%, we need to decrease the
209 * upper limit to make the calculation more accurate.
210 */
211 cpuid(0x80860007, &eax, &ebx, &ecx, &edx);
212 /* try decreasing in 10% steps, some processors react only
213 * on some barrier values */
214 for (try_hi = 80; try_hi > 0 && ecx > 90; try_hi -= 10) {
215 /* set to 0 to try_hi perf_pctg */
216 msr_lo &= 0xFFFFFF80;
217 msr_hi &= 0xFFFFFF80;
218 msr_hi |= try_hi;
219 wrmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi);
220
221 /* read out current core MHz and current perf_pctg */
222 cpuid(0x80860007, &eax, &ebx, &ecx, &edx);
223
224 /* restore values */
225 wrmsr(MSR_TMTA_LONGRUN_CTRL, save_lo, save_hi);
226 }
227 pr_debug("percentage is %u %%, freq is %u MHz\n", ecx, eax);
228
229 /* performance_pctg = (current_freq - low_freq)/(high_freq - low_freq)
230 * eqals
231 * low_freq * (1 - perf_pctg) = (cur_freq - high_freq * perf_pctg)
232 *
233 * high_freq * perf_pctg is stored tempoarily into "ebx".
234 */
235 ebx = (((cpu_khz / 1000) * ecx) / 100); /* to MHz */
236
237 if ((ecx > 95) || (ecx == 0) || (eax < ebx))
238 return -EIO;
239
240 edx = ((eax - ebx) * 100) / (100 - ecx);
241 *low_freq = edx * 1000; /* back to kHz */
242
243 pr_debug("low frequency is %u kHz\n", *low_freq);
244
245 if (*low_freq > *high_freq)
246 *low_freq = *high_freq;
247
248 return 0;
249}
250
251
252static int longrun_cpu_init(struct cpufreq_policy *policy)
253{
254 int result = 0;
255
256 /* capability check */
257 if (policy->cpu != 0)
258 return -ENODEV;
259
260 /* detect low and high frequency */
261 result = longrun_determine_freqs(&longrun_low_freq, &longrun_high_freq);
262 if (result)
263 return result;
264
265 /* cpuinfo and default policy values */
266 policy->cpuinfo.min_freq = longrun_low_freq;
267 policy->cpuinfo.max_freq = longrun_high_freq;
268 longrun_get_policy(policy);
269
270 return 0;
271}
272
273
274static struct cpufreq_driver longrun_driver = {
275 .flags = CPUFREQ_CONST_LOOPS,
276 .verify = longrun_verify_policy,
277 .setpolicy = longrun_set_policy,
278 .get = longrun_get,
279 .init = longrun_cpu_init,
280 .name = "longrun",
281};
282
283static const struct x86_cpu_id longrun_ids[] = {
284 X86_MATCH_VENDOR_FEATURE(TRANSMETA, X86_FEATURE_LONGRUN, NULL),
285 {}
286};
287MODULE_DEVICE_TABLE(x86cpu, longrun_ids);
288
289/**
290 * longrun_init - initializes the Transmeta Crusoe LongRun CPUFreq driver
291 *
292 * Initializes the LongRun support.
293 */
294static int __init longrun_init(void)
295{
296 if (!x86_match_cpu(longrun_ids))
297 return -ENODEV;
298 return cpufreq_register_driver(&longrun_driver);
299}
300
301
302/**
303 * longrun_exit - unregisters LongRun support
304 */
305static void __exit longrun_exit(void)
306{
307 cpufreq_unregister_driver(&longrun_driver);
308}
309
310
311MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>");
312MODULE_DESCRIPTION("LongRun driver for Transmeta Crusoe and "
313 "Efficeon processors.");
314MODULE_LICENSE("GPL");
315
316module_init(longrun_init);
317module_exit(longrun_exit);