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1da177e4 LT |
1 | /* |
2 | * (C) 2002 - 2003 Dominik Brodowski <[email protected]> | |
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> | |
1da177e4 | 12 | #include <linux/cpufreq.h> |
48ee923a | 13 | #include <linux/timex.h> |
1da177e4 LT |
14 | |
15 | #include <asm/msr.h> | |
16 | #include <asm/processor.h> | |
fa8031ae | 17 | #include <asm/cpu_device_id.h> |
1da177e4 | 18 | |
221dee28 | 19 | static struct cpufreq_driver longrun_driver; |
1da177e4 LT |
20 | |
21 | /** | |
22 | * longrun_{low,high}_freq is needed for the conversion of cpufreq kHz | |
23 | * values into per cent values. In TMTA microcode, the following is valid: | |
24 | * performance_pctg = (current_freq - low_freq)/(high_freq - low_freq) | |
25 | */ | |
26 | static unsigned int longrun_low_freq, longrun_high_freq; | |
27 | ||
28 | ||
29 | /** | |
30 | * longrun_get_policy - get the current LongRun policy | |
31 | * @policy: struct cpufreq_policy where current policy is written into | |
32 | * | |
33 | * Reads the current LongRun policy by access to MSR_TMTA_LONGRUN_FLAGS | |
34 | * and MSR_TMTA_LONGRUN_CTRL | |
35 | */ | |
2760984f | 36 | static void longrun_get_policy(struct cpufreq_policy *policy) |
1da177e4 LT |
37 | { |
38 | u32 msr_lo, msr_hi; | |
39 | ||
40 | rdmsr(MSR_TMTA_LONGRUN_FLAGS, msr_lo, msr_hi); | |
2d06d8c4 | 41 | pr_debug("longrun flags are %x - %x\n", msr_lo, msr_hi); |
1da177e4 LT |
42 | if (msr_lo & 0x01) |
43 | policy->policy = CPUFREQ_POLICY_PERFORMANCE; | |
44 | else | |
45 | policy->policy = CPUFREQ_POLICY_POWERSAVE; | |
46 | ||
47 | rdmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi); | |
2d06d8c4 | 48 | pr_debug("longrun ctrl is %x - %x\n", msr_lo, msr_hi); |
1da177e4 LT |
49 | msr_lo &= 0x0000007F; |
50 | msr_hi &= 0x0000007F; | |
51 | ||
48ee923a | 52 | if (longrun_high_freq <= longrun_low_freq) { |
1da177e4 LT |
53 | /* Assume degenerate Longrun table */ |
54 | policy->min = policy->max = longrun_high_freq; | |
55 | } else { | |
56 | policy->min = longrun_low_freq + msr_lo * | |
57 | ((longrun_high_freq - longrun_low_freq) / 100); | |
58 | policy->max = longrun_low_freq + msr_hi * | |
59 | ((longrun_high_freq - longrun_low_freq) / 100); | |
60 | } | |
61 | policy->cpu = 0; | |
62 | } | |
63 | ||
64 | ||
65 | /** | |
66 | * longrun_set_policy - sets a new CPUFreq policy | |
67 | * @policy: new policy | |
68 | * | |
69 | * Sets a new CPUFreq policy on LongRun-capable processors. This function | |
70 | * has to be called with cpufreq_driver locked. | |
71 | */ | |
72 | static int longrun_set_policy(struct cpufreq_policy *policy) | |
73 | { | |
74 | u32 msr_lo, msr_hi; | |
75 | u32 pctg_lo, pctg_hi; | |
76 | ||
77 | if (!policy) | |
78 | return -EINVAL; | |
79 | ||
48ee923a | 80 | if (longrun_high_freq <= longrun_low_freq) { |
1da177e4 LT |
81 | /* Assume degenerate Longrun table */ |
82 | pctg_lo = pctg_hi = 100; | |
83 | } else { | |
84 | pctg_lo = (policy->min - longrun_low_freq) / | |
85 | ((longrun_high_freq - longrun_low_freq) / 100); | |
86 | pctg_hi = (policy->max - longrun_low_freq) / | |
87 | ((longrun_high_freq - longrun_low_freq) / 100); | |
88 | } | |
89 | ||
90 | if (pctg_hi > 100) | |
91 | pctg_hi = 100; | |
92 | if (pctg_lo > pctg_hi) | |
93 | pctg_lo = pctg_hi; | |
94 | ||
95 | /* performance or economy mode */ | |
96 | rdmsr(MSR_TMTA_LONGRUN_FLAGS, msr_lo, msr_hi); | |
97 | msr_lo &= 0xFFFFFFFE; | |
98 | switch (policy->policy) { | |
99 | case CPUFREQ_POLICY_PERFORMANCE: | |
100 | msr_lo |= 0x00000001; | |
101 | break; | |
102 | case CPUFREQ_POLICY_POWERSAVE: | |
103 | break; | |
104 | } | |
105 | wrmsr(MSR_TMTA_LONGRUN_FLAGS, msr_lo, msr_hi); | |
106 | ||
107 | /* lower and upper boundary */ | |
108 | rdmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi); | |
109 | msr_lo &= 0xFFFFFF80; | |
110 | msr_hi &= 0xFFFFFF80; | |
111 | msr_lo |= pctg_lo; | |
112 | msr_hi |= pctg_hi; | |
113 | wrmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi); | |
114 | ||
115 | return 0; | |
116 | } | |
117 | ||
118 | ||
119 | /** | |
120 | * longrun_verify_poliy - verifies a new CPUFreq policy | |
121 | * @policy: the policy to verify | |
122 | * | |
123 | * Validates a new CPUFreq policy. This function has to be called with | |
124 | * cpufreq_driver locked. | |
125 | */ | |
126 | static int longrun_verify_policy(struct cpufreq_policy *policy) | |
127 | { | |
128 | if (!policy) | |
129 | return -EINVAL; | |
130 | ||
131 | policy->cpu = 0; | |
be49e346 | 132 | cpufreq_verify_within_cpu_limits(policy); |
1da177e4 LT |
133 | |
134 | if ((policy->policy != CPUFREQ_POLICY_POWERSAVE) && | |
135 | (policy->policy != CPUFREQ_POLICY_PERFORMANCE)) | |
136 | return -EINVAL; | |
137 | ||
138 | return 0; | |
139 | } | |
140 | ||
141 | static unsigned int longrun_get(unsigned int cpu) | |
142 | { | |
143 | u32 eax, ebx, ecx, edx; | |
144 | ||
145 | if (cpu) | |
146 | return 0; | |
147 | ||
148 | cpuid(0x80860007, &eax, &ebx, &ecx, &edx); | |
2d06d8c4 | 149 | pr_debug("cpuid eax is %u\n", eax); |
1da177e4 | 150 | |
48ee923a | 151 | return eax * 1000; |
1da177e4 LT |
152 | } |
153 | ||
154 | /** | |
155 | * longrun_determine_freqs - determines the lowest and highest possible core frequency | |
156 | * @low_freq: an int to put the lowest frequency into | |
157 | * @high_freq: an int to put the highest frequency into | |
158 | * | |
159 | * Determines the lowest and highest possible core frequencies on this CPU. | |
160 | * This is necessary to calculate the performance percentage according to | |
161 | * TMTA rules: | |
162 | * performance_pctg = (target_freq - low_freq)/(high_freq - low_freq) | |
163 | */ | |
2760984f | 164 | static int longrun_determine_freqs(unsigned int *low_freq, |
7e2d8112 | 165 | unsigned int *high_freq) |
1da177e4 LT |
166 | { |
167 | u32 msr_lo, msr_hi; | |
168 | u32 save_lo, save_hi; | |
169 | u32 eax, ebx, ecx, edx; | |
170 | u32 try_hi; | |
92cb7612 | 171 | struct cpuinfo_x86 *c = &cpu_data(0); |
1da177e4 LT |
172 | |
173 | if (!low_freq || !high_freq) | |
174 | return -EINVAL; | |
175 | ||
176 | if (cpu_has(c, X86_FEATURE_LRTI)) { | |
177 | /* if the LongRun Table Interface is present, the | |
178 | * detection is a bit easier: | |
179 | * For minimum frequency, read out the maximum | |
180 | * level (msr_hi), write that into "currently | |
181 | * selected level", and read out the frequency. | |
182 | * For maximum frequency, read out level zero. | |
183 | */ | |
184 | /* minimum */ | |
185 | rdmsr(MSR_TMTA_LRTI_READOUT, msr_lo, msr_hi); | |
186 | wrmsr(MSR_TMTA_LRTI_READOUT, msr_hi, msr_hi); | |
187 | rdmsr(MSR_TMTA_LRTI_VOLT_MHZ, msr_lo, msr_hi); | |
188 | *low_freq = msr_lo * 1000; /* to kHz */ | |
189 | ||
190 | /* maximum */ | |
191 | wrmsr(MSR_TMTA_LRTI_READOUT, 0, msr_hi); | |
192 | rdmsr(MSR_TMTA_LRTI_VOLT_MHZ, msr_lo, msr_hi); | |
193 | *high_freq = msr_lo * 1000; /* to kHz */ | |
194 | ||
2d06d8c4 | 195 | pr_debug("longrun table interface told %u - %u kHz\n", |
48ee923a | 196 | *low_freq, *high_freq); |
1da177e4 LT |
197 | |
198 | if (*low_freq > *high_freq) | |
199 | *low_freq = *high_freq; | |
200 | return 0; | |
201 | } | |
202 | ||
203 | /* set the upper border to the value determined during TSC init */ | |
204 | *high_freq = (cpu_khz / 1000); | |
205 | *high_freq = *high_freq * 1000; | |
2d06d8c4 | 206 | pr_debug("high frequency is %u kHz\n", *high_freq); |
1da177e4 LT |
207 | |
208 | /* get current borders */ | |
209 | rdmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi); | |
210 | save_lo = msr_lo & 0x0000007F; | |
211 | save_hi = msr_hi & 0x0000007F; | |
212 | ||
213 | /* if current perf_pctg is larger than 90%, we need to decrease the | |
214 | * upper limit to make the calculation more accurate. | |
215 | */ | |
216 | cpuid(0x80860007, &eax, &ebx, &ecx, &edx); | |
217 | /* try decreasing in 10% steps, some processors react only | |
218 | * on some barrier values */ | |
48ee923a | 219 | for (try_hi = 80; try_hi > 0 && ecx > 90; try_hi -= 10) { |
1da177e4 LT |
220 | /* set to 0 to try_hi perf_pctg */ |
221 | msr_lo &= 0xFFFFFF80; | |
222 | msr_hi &= 0xFFFFFF80; | |
1da177e4 LT |
223 | msr_hi |= try_hi; |
224 | wrmsr(MSR_TMTA_LONGRUN_CTRL, msr_lo, msr_hi); | |
225 | ||
226 | /* read out current core MHz and current perf_pctg */ | |
227 | cpuid(0x80860007, &eax, &ebx, &ecx, &edx); | |
228 | ||
229 | /* restore values */ | |
230 | wrmsr(MSR_TMTA_LONGRUN_CTRL, save_lo, save_hi); | |
231 | } | |
2d06d8c4 | 232 | pr_debug("percentage is %u %%, freq is %u MHz\n", ecx, eax); |
1da177e4 LT |
233 | |
234 | /* performance_pctg = (current_freq - low_freq)/(high_freq - low_freq) | |
235 | * eqals | |
48ee923a | 236 | * low_freq * (1 - perf_pctg) = (cur_freq - high_freq * perf_pctg) |
1da177e4 LT |
237 | * |
238 | * high_freq * perf_pctg is stored tempoarily into "ebx". | |
239 | */ | |
240 | ebx = (((cpu_khz / 1000) * ecx) / 100); /* to MHz */ | |
241 | ||
242 | if ((ecx > 95) || (ecx == 0) || (eax < ebx)) | |
243 | return -EIO; | |
244 | ||
667ad4f7 | 245 | edx = ((eax - ebx) * 100) / (100 - ecx); |
1da177e4 LT |
246 | *low_freq = edx * 1000; /* back to kHz */ |
247 | ||
2d06d8c4 | 248 | pr_debug("low frequency is %u kHz\n", *low_freq); |
1da177e4 LT |
249 | |
250 | if (*low_freq > *high_freq) | |
251 | *low_freq = *high_freq; | |
252 | ||
253 | return 0; | |
254 | } | |
255 | ||
256 | ||
2760984f | 257 | static int longrun_cpu_init(struct cpufreq_policy *policy) |
1da177e4 LT |
258 | { |
259 | int result = 0; | |
260 | ||
261 | /* capability check */ | |
262 | if (policy->cpu != 0) | |
263 | return -ENODEV; | |
264 | ||
265 | /* detect low and high frequency */ | |
266 | result = longrun_determine_freqs(&longrun_low_freq, &longrun_high_freq); | |
267 | if (result) | |
268 | return result; | |
269 | ||
270 | /* cpuinfo and default policy values */ | |
271 | policy->cpuinfo.min_freq = longrun_low_freq; | |
272 | policy->cpuinfo.max_freq = longrun_high_freq; | |
273 | policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; | |
274 | longrun_get_policy(policy); | |
275 | ||
276 | return 0; | |
277 | } | |
278 | ||
279 | ||
221dee28 | 280 | static struct cpufreq_driver longrun_driver = { |
1da177e4 LT |
281 | .flags = CPUFREQ_CONST_LOOPS, |
282 | .verify = longrun_verify_policy, | |
283 | .setpolicy = longrun_set_policy, | |
284 | .get = longrun_get, | |
285 | .init = longrun_cpu_init, | |
286 | .name = "longrun", | |
1da177e4 LT |
287 | }; |
288 | ||
fa8031ae AK |
289 | static const struct x86_cpu_id longrun_ids[] = { |
290 | { X86_VENDOR_TRANSMETA, X86_FAMILY_ANY, X86_MODEL_ANY, | |
291 | X86_FEATURE_LONGRUN }, | |
292 | {} | |
293 | }; | |
294 | MODULE_DEVICE_TABLE(x86cpu, longrun_ids); | |
1da177e4 LT |
295 | |
296 | /** | |
297 | * longrun_init - initializes the Transmeta Crusoe LongRun CPUFreq driver | |
298 | * | |
299 | * Initializes the LongRun support. | |
300 | */ | |
301 | static int __init longrun_init(void) | |
302 | { | |
fa8031ae | 303 | if (!x86_match_cpu(longrun_ids)) |
1da177e4 | 304 | return -ENODEV; |
1da177e4 LT |
305 | return cpufreq_register_driver(&longrun_driver); |
306 | } | |
307 | ||
308 | ||
309 | /** | |
310 | * longrun_exit - unregisters LongRun support | |
311 | */ | |
312 | static void __exit longrun_exit(void) | |
313 | { | |
314 | cpufreq_unregister_driver(&longrun_driver); | |
315 | } | |
316 | ||
317 | ||
48ee923a DJ |
318 | MODULE_AUTHOR("Dominik Brodowski <[email protected]>"); |
319 | MODULE_DESCRIPTION("LongRun driver for Transmeta Crusoe and " | |
320 | "Efficeon processors."); | |
321 | MODULE_LICENSE("GPL"); | |
1da177e4 LT |
322 | |
323 | module_init(longrun_init); | |
324 | module_exit(longrun_exit); |