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4f19048f | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de> | |
4 | * | |
1da177e4 LT |
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> | |
1da177e4 | 11 | #include <linux/cpufreq.h> |
48ee923a | 12 | #include <linux/timex.h> |
1da177e4 LT |
13 | |
14 | #include <asm/msr.h> | |
15 | #include <asm/processor.h> | |
fa8031ae | 16 | #include <asm/cpu_device_id.h> |
1da177e4 | 17 | |
221dee28 | 18 | static struct cpufreq_driver longrun_driver; |
1da177e4 LT |
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 | */ | |
25 | static 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 | */ | |
2760984f | 35 | static void longrun_get_policy(struct cpufreq_policy *policy) |
1da177e4 LT |
36 | { |
37 | u32 msr_lo, msr_hi; | |
38 | ||
39 | rdmsr(MSR_TMTA_LONGRUN_FLAGS, msr_lo, msr_hi); | |
2d06d8c4 | 40 | pr_debug("longrun flags are %x - %x\n", msr_lo, msr_hi); |
1da177e4 LT |
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); | |
2d06d8c4 | 47 | pr_debug("longrun ctrl is %x - %x\n", msr_lo, msr_hi); |
1da177e4 LT |
48 | msr_lo &= 0x0000007F; |
49 | msr_hi &= 0x0000007F; | |
50 | ||
48ee923a | 51 | if (longrun_high_freq <= longrun_low_freq) { |
1da177e4 LT |
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 | */ | |
71 | static 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 | ||
48ee923a | 79 | if (longrun_high_freq <= longrun_low_freq) { |
1da177e4 LT |
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 | */ | |
1e4f63ae | 125 | static int longrun_verify_policy(struct cpufreq_policy_data *policy) |
1da177e4 LT |
126 | { |
127 | if (!policy) | |
128 | return -EINVAL; | |
129 | ||
130 | policy->cpu = 0; | |
be49e346 | 131 | cpufreq_verify_within_cpu_limits(policy); |
1da177e4 | 132 | |
1da177e4 LT |
133 | return 0; |
134 | } | |
135 | ||
136 | static 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); | |
2d06d8c4 | 144 | pr_debug("cpuid eax is %u\n", eax); |
1da177e4 | 145 | |
48ee923a | 146 | return eax * 1000; |
1da177e4 LT |
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 | */ | |
2760984f | 159 | static int longrun_determine_freqs(unsigned int *low_freq, |
7e2d8112 | 160 | unsigned int *high_freq) |
1da177e4 LT |
161 | { |
162 | u32 msr_lo, msr_hi; | |
163 | u32 save_lo, save_hi; | |
164 | u32 eax, ebx, ecx, edx; | |
165 | u32 try_hi; | |
92cb7612 | 166 | struct cpuinfo_x86 *c = &cpu_data(0); |
1da177e4 LT |
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 | ||
2d06d8c4 | 190 | pr_debug("longrun table interface told %u - %u kHz\n", |
48ee923a | 191 | *low_freq, *high_freq); |
1da177e4 LT |
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; | |
2d06d8c4 | 201 | pr_debug("high frequency is %u kHz\n", *high_freq); |
1da177e4 LT |
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 */ | |
48ee923a | 214 | for (try_hi = 80; try_hi > 0 && ecx > 90; try_hi -= 10) { |
1da177e4 LT |
215 | /* set to 0 to try_hi perf_pctg */ |
216 | msr_lo &= 0xFFFFFF80; | |
217 | msr_hi &= 0xFFFFFF80; | |
1da177e4 LT |
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 | } | |
2d06d8c4 | 227 | pr_debug("percentage is %u %%, freq is %u MHz\n", ecx, eax); |
1da177e4 LT |
228 | |
229 | /* performance_pctg = (current_freq - low_freq)/(high_freq - low_freq) | |
230 | * eqals | |
48ee923a | 231 | * low_freq * (1 - perf_pctg) = (cur_freq - high_freq * perf_pctg) |
1da177e4 LT |
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 | ||
667ad4f7 | 240 | edx = ((eax - ebx) * 100) / (100 - ecx); |
1da177e4 LT |
241 | *low_freq = edx * 1000; /* back to kHz */ |
242 | ||
2d06d8c4 | 243 | pr_debug("low frequency is %u kHz\n", *low_freq); |
1da177e4 LT |
244 | |
245 | if (*low_freq > *high_freq) | |
246 | *low_freq = *high_freq; | |
247 | ||
248 | return 0; | |
249 | } | |
250 | ||
251 | ||
2760984f | 252 | static int longrun_cpu_init(struct cpufreq_policy *policy) |
1da177e4 LT |
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; | |
1da177e4 LT |
268 | longrun_get_policy(policy); |
269 | ||
270 | return 0; | |
271 | } | |
272 | ||
273 | ||
221dee28 | 274 | static struct cpufreq_driver longrun_driver = { |
1da177e4 LT |
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", | |
1da177e4 LT |
281 | }; |
282 | ||
fa8031ae | 283 | static const struct x86_cpu_id longrun_ids[] = { |
b11d77fa | 284 | X86_MATCH_VENDOR_FEATURE(TRANSMETA, X86_FEATURE_LONGRUN, NULL), |
fa8031ae AK |
285 | {} |
286 | }; | |
287 | MODULE_DEVICE_TABLE(x86cpu, longrun_ids); | |
1da177e4 LT |
288 | |
289 | /** | |
290 | * longrun_init - initializes the Transmeta Crusoe LongRun CPUFreq driver | |
291 | * | |
292 | * Initializes the LongRun support. | |
293 | */ | |
294 | static int __init longrun_init(void) | |
295 | { | |
fa8031ae | 296 | if (!x86_match_cpu(longrun_ids)) |
1da177e4 | 297 | return -ENODEV; |
1da177e4 LT |
298 | return cpufreq_register_driver(&longrun_driver); |
299 | } | |
300 | ||
301 | ||
302 | /** | |
303 | * longrun_exit - unregisters LongRun support | |
304 | */ | |
305 | static void __exit longrun_exit(void) | |
306 | { | |
307 | cpufreq_unregister_driver(&longrun_driver); | |
308 | } | |
309 | ||
310 | ||
48ee923a DJ |
311 | MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>"); |
312 | MODULE_DESCRIPTION("LongRun driver for Transmeta Crusoe and " | |
313 | "Efficeon processors."); | |
314 | MODULE_LICENSE("GPL"); | |
1da177e4 LT |
315 | |
316 | module_init(longrun_init); | |
317 | module_exit(longrun_exit); |