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1 | /* |
2 | * Intel SpeedStep SMI driver. |
3 | * |
4 | * (C) 2003 Hiroshi Miura <miura@da-cha.org> |
5 | * |
6 | * Licensed under the terms of the GNU GPL License version 2. |
7 | * |
8 | */ |
9 | |
10 | |
11 | /********************************************************************* |
12 | * SPEEDSTEP - DEFINITIONS * |
13 | *********************************************************************/ |
14 | |
15 | #include <linux/kernel.h> |
16 | #include <linux/module.h> |
17 | #include <linux/moduleparam.h> |
18 | #include <linux/init.h> |
19 | #include <linux/cpufreq.h> |
20 | #include <linux/delay.h> |
21 | #include <linux/io.h> |
22 | #include <asm/ist.h> |
23 | #include <asm/cpu_device_id.h> |
24 | |
25 | #include "speedstep-lib.h" |
26 | |
27 | /* speedstep system management interface port/command. |
28 | * |
29 | * These parameters are got from IST-SMI BIOS call. |
30 | * If user gives it, these are used. |
31 | * |
32 | */ |
33 | static int smi_port; |
34 | static int smi_cmd; |
35 | static unsigned int smi_sig; |
36 | |
37 | /* info about the processor */ |
38 | static enum speedstep_processor speedstep_processor; |
39 | |
40 | /* |
41 | * There are only two frequency states for each processor. Values |
42 | * are in kHz for the time being. |
43 | */ |
44 | static struct cpufreq_frequency_table speedstep_freqs[] = { |
45 | {SPEEDSTEP_HIGH, 0}, |
46 | {SPEEDSTEP_LOW, 0}, |
47 | {0, CPUFREQ_TABLE_END}, |
48 | }; |
49 | |
50 | #define GET_SPEEDSTEP_OWNER 0 |
51 | #define GET_SPEEDSTEP_STATE 1 |
52 | #define SET_SPEEDSTEP_STATE 2 |
53 | #define GET_SPEEDSTEP_FREQS 4 |
54 | |
55 | /* how often shall the SMI call be tried if it failed, e.g. because |
56 | * of DMA activity going on? */ |
57 | #define SMI_TRIES 5 |
58 | |
59 | /** |
60 | * speedstep_smi_ownership |
61 | */ |
62 | static int speedstep_smi_ownership(void) |
63 | { |
64 | u32 command, result, magic, dummy; |
65 | u32 function = GET_SPEEDSTEP_OWNER; |
66 | unsigned char magic_data[] = "Copyright (c) 1999 Intel Corporation"; |
67 | |
68 | command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff); |
69 | magic = virt_to_phys(magic_data); |
70 | |
71 | pr_debug("trying to obtain ownership with command %x at port %x\n", |
72 | command, smi_port); |
73 | |
74 | __asm__ __volatile__( |
75 | "push %%ebp\n" |
76 | "out %%al, (%%dx)\n" |
77 | "pop %%ebp\n" |
78 | : "=D" (result), |
79 | "=a" (dummy), "=b" (dummy), "=c" (dummy), "=d" (dummy), |
80 | "=S" (dummy) |
81 | : "a" (command), "b" (function), "c" (0), "d" (smi_port), |
82 | "D" (0), "S" (magic) |
83 | : "memory" |
84 | ); |
85 | |
86 | pr_debug("result is %x\n", result); |
87 | |
88 | return result; |
89 | } |
90 | |
91 | /** |
92 | * speedstep_smi_get_freqs - get SpeedStep preferred & current freq. |
93 | * @low: the low frequency value is placed here |
94 | * @high: the high frequency value is placed here |
95 | * |
96 | * Only available on later SpeedStep-enabled systems, returns false results or |
97 | * even hangs [cf. bugme.osdl.org # 1422] on earlier systems. Empirical testing |
98 | * shows that the latter occurs if !(ist_info.event & 0xFFFF). |
99 | */ |
100 | static int speedstep_smi_get_freqs(unsigned int *low, unsigned int *high) |
101 | { |
102 | u32 command, result = 0, edi, high_mhz, low_mhz, dummy; |
103 | u32 state = 0; |
104 | u32 function = GET_SPEEDSTEP_FREQS; |
105 | |
106 | if (!(ist_info.event & 0xFFFF)) { |
107 | pr_debug("bug #1422 -- can't read freqs from BIOS\n"); |
108 | return -ENODEV; |
109 | } |
110 | |
111 | command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff); |
112 | |
113 | pr_debug("trying to determine frequencies with command %x at port %x\n", |
114 | command, smi_port); |
115 | |
116 | __asm__ __volatile__( |
117 | "push %%ebp\n" |
118 | "out %%al, (%%dx)\n" |
119 | "pop %%ebp" |
120 | : "=a" (result), |
121 | "=b" (high_mhz), |
122 | "=c" (low_mhz), |
123 | "=d" (state), "=D" (edi), "=S" (dummy) |
124 | : "a" (command), |
125 | "b" (function), |
126 | "c" (state), |
127 | "d" (smi_port), "S" (0), "D" (0) |
128 | ); |
129 | |
130 | pr_debug("result %x, low_freq %u, high_freq %u\n", |
131 | result, low_mhz, high_mhz); |
132 | |
133 | /* abort if results are obviously incorrect... */ |
134 | if ((high_mhz + low_mhz) < 600) |
135 | return -EINVAL; |
136 | |
137 | *high = high_mhz * 1000; |
138 | *low = low_mhz * 1000; |
139 | |
140 | return result; |
141 | } |
142 | |
143 | /** |
144 | * speedstep_get_state - set the SpeedStep state |
145 | * @state: processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH) |
146 | * |
147 | */ |
148 | static int speedstep_get_state(void) |
149 | { |
150 | u32 function = GET_SPEEDSTEP_STATE; |
151 | u32 result, state, edi, command, dummy; |
152 | |
153 | command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff); |
154 | |
155 | pr_debug("trying to determine current setting with command %x " |
156 | "at port %x\n", command, smi_port); |
157 | |
158 | __asm__ __volatile__( |
159 | "push %%ebp\n" |
160 | "out %%al, (%%dx)\n" |
161 | "pop %%ebp\n" |
162 | : "=a" (result), |
163 | "=b" (state), "=D" (edi), |
164 | "=c" (dummy), "=d" (dummy), "=S" (dummy) |
165 | : "a" (command), "b" (function), "c" (0), |
166 | "d" (smi_port), "S" (0), "D" (0) |
167 | ); |
168 | |
169 | pr_debug("state is %x, result is %x\n", state, result); |
170 | |
171 | return state & 1; |
172 | } |
173 | |
174 | |
175 | /** |
176 | * speedstep_set_state - set the SpeedStep state |
177 | * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH) |
178 | * |
179 | */ |
180 | static void speedstep_set_state(unsigned int state) |
181 | { |
182 | unsigned int result = 0, command, new_state, dummy; |
183 | unsigned long flags; |
184 | unsigned int function = SET_SPEEDSTEP_STATE; |
185 | unsigned int retry = 0; |
186 | |
187 | if (state > 0x1) |
188 | return; |
189 | |
190 | /* Disable IRQs */ |
191 | local_irq_save(flags); |
192 | |
193 | command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff); |
194 | |
195 | pr_debug("trying to set frequency to state %u " |
196 | "with command %x at port %x\n", |
197 | state, command, smi_port); |
198 | |
199 | do { |
200 | if (retry) { |
201 | pr_debug("retry %u, previous result %u, waiting...\n", |
202 | retry, result); |
203 | mdelay(retry * 50); |
204 | } |
205 | retry++; |
206 | __asm__ __volatile__( |
207 | "push %%ebp\n" |
208 | "out %%al, (%%dx)\n" |
209 | "pop %%ebp" |
210 | : "=b" (new_state), "=D" (result), |
211 | "=c" (dummy), "=a" (dummy), |
212 | "=d" (dummy), "=S" (dummy) |
213 | : "a" (command), "b" (function), "c" (state), |
214 | "d" (smi_port), "S" (0), "D" (0) |
215 | ); |
216 | } while ((new_state != state) && (retry <= SMI_TRIES)); |
217 | |
218 | /* enable IRQs */ |
219 | local_irq_restore(flags); |
220 | |
221 | if (new_state == state) |
222 | pr_debug("change to %u MHz succeeded after %u tries " |
223 | "with result %u\n", |
224 | (speedstep_freqs[new_state].frequency / 1000), |
225 | retry, result); |
226 | else |
227 | printk(KERN_ERR "cpufreq: change to state %u " |
228 | "failed with new_state %u and result %u\n", |
229 | state, new_state, result); |
230 | |
231 | return; |
232 | } |
233 | |
234 | |
235 | /** |
236 | * speedstep_target - set a new CPUFreq policy |
237 | * @policy: new policy |
238 | * @target_freq: new freq |
239 | * @relation: |
240 | * |
241 | * Sets a new CPUFreq policy/freq. |
242 | */ |
243 | static int speedstep_target(struct cpufreq_policy *policy, |
244 | unsigned int target_freq, unsigned int relation) |
245 | { |
246 | unsigned int newstate = 0; |
247 | struct cpufreq_freqs freqs; |
248 | |
249 | if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0], |
250 | target_freq, relation, &newstate)) |
251 | return -EINVAL; |
252 | |
253 | freqs.old = speedstep_freqs[speedstep_get_state()].frequency; |
254 | freqs.new = speedstep_freqs[newstate].frequency; |
255 | freqs.cpu = 0; /* speedstep.c is UP only driver */ |
256 | |
257 | if (freqs.old == freqs.new) |
258 | return 0; |
259 | |
260 | cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); |
261 | speedstep_set_state(newstate); |
262 | cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); |
263 | |
264 | return 0; |
265 | } |
266 | |
267 | |
268 | /** |
269 | * speedstep_verify - verifies a new CPUFreq policy |
270 | * @policy: new policy |
271 | * |
272 | * Limit must be within speedstep_low_freq and speedstep_high_freq, with |
273 | * at least one border included. |
274 | */ |
275 | static int speedstep_verify(struct cpufreq_policy *policy) |
276 | { |
277 | return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]); |
278 | } |
279 | |
280 | |
281 | static int speedstep_cpu_init(struct cpufreq_policy *policy) |
282 | { |
283 | int result; |
284 | unsigned int speed, state; |
285 | unsigned int *low, *high; |
286 | |
287 | /* capability check */ |
288 | if (policy->cpu != 0) |
289 | return -ENODEV; |
290 | |
291 | result = speedstep_smi_ownership(); |
292 | if (result) { |
293 | pr_debug("fails in acquiring ownership of a SMI interface.\n"); |
294 | return -EINVAL; |
295 | } |
296 | |
297 | /* detect low and high frequency */ |
298 | low = &speedstep_freqs[SPEEDSTEP_LOW].frequency; |
299 | high = &speedstep_freqs[SPEEDSTEP_HIGH].frequency; |
300 | |
301 | result = speedstep_smi_get_freqs(low, high); |
302 | if (result) { |
303 | /* fall back to speedstep_lib.c dection mechanism: |
304 | * try both states out */ |
305 | pr_debug("could not detect low and high frequencies " |
306 | "by SMI call.\n"); |
307 | result = speedstep_get_freqs(speedstep_processor, |
308 | low, high, |
309 | NULL, |
310 | &speedstep_set_state); |
311 | |
312 | if (result) { |
313 | pr_debug("could not detect two different speeds" |
314 | " -- aborting.\n"); |
315 | return result; |
316 | } else |
317 | pr_debug("workaround worked.\n"); |
318 | } |
319 | |
320 | /* get current speed setting */ |
321 | state = speedstep_get_state(); |
322 | speed = speedstep_freqs[state].frequency; |
323 | |
324 | pr_debug("currently at %s speed setting - %i MHz\n", |
325 | (speed == speedstep_freqs[SPEEDSTEP_LOW].frequency) |
326 | ? "low" : "high", |
327 | (speed / 1000)); |
328 | |
329 | /* cpuinfo and default policy values */ |
330 | policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; |
331 | policy->cur = speed; |
332 | |
333 | result = cpufreq_frequency_table_cpuinfo(policy, speedstep_freqs); |
334 | if (result) |
335 | return result; |
336 | |
337 | cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu); |
338 | |
339 | return 0; |
340 | } |
341 | |
342 | static int speedstep_cpu_exit(struct cpufreq_policy *policy) |
343 | { |
344 | cpufreq_frequency_table_put_attr(policy->cpu); |
345 | return 0; |
346 | } |
347 | |
348 | static unsigned int speedstep_get(unsigned int cpu) |
349 | { |
350 | if (cpu) |
351 | return -ENODEV; |
352 | return speedstep_get_frequency(speedstep_processor); |
353 | } |
354 | |
355 | |
356 | static int speedstep_resume(struct cpufreq_policy *policy) |
357 | { |
358 | int result = speedstep_smi_ownership(); |
359 | |
360 | if (result) |
361 | pr_debug("fails in re-acquiring ownership of a SMI interface.\n"); |
362 | |
363 | return result; |
364 | } |
365 | |
366 | static struct freq_attr *speedstep_attr[] = { |
367 | &cpufreq_freq_attr_scaling_available_freqs, |
368 | NULL, |
369 | }; |
370 | |
371 | static struct cpufreq_driver speedstep_driver = { |
372 | .name = "speedstep-smi", |
373 | .verify = speedstep_verify, |
374 | .target = speedstep_target, |
375 | .init = speedstep_cpu_init, |
376 | .exit = speedstep_cpu_exit, |
377 | .get = speedstep_get, |
378 | .resume = speedstep_resume, |
379 | .owner = THIS_MODULE, |
380 | .attr = speedstep_attr, |
381 | }; |
382 | |
383 | static const struct x86_cpu_id ss_smi_ids[] = { |
384 | { X86_VENDOR_INTEL, 6, 0xb, }, |
385 | { X86_VENDOR_INTEL, 6, 0x8, }, |
386 | { X86_VENDOR_INTEL, 15, 2 }, |
387 | {} |
388 | }; |
389 | #if 0 |
390 | /* Not auto loaded currently */ |
391 | MODULE_DEVICE_TABLE(x86cpu, ss_smi_ids); |
392 | #endif |
393 | |
394 | /** |
395 | * speedstep_init - initializes the SpeedStep CPUFreq driver |
396 | * |
397 | * Initializes the SpeedStep support. Returns -ENODEV on unsupported |
398 | * BIOS, -EINVAL on problems during initiatization, and zero on |
399 | * success. |
400 | */ |
401 | static int __init speedstep_init(void) |
402 | { |
403 | if (!x86_match_cpu(ss_smi_ids)) |
404 | return -ENODEV; |
405 | |
406 | speedstep_processor = speedstep_detect_processor(); |
407 | |
408 | switch (speedstep_processor) { |
409 | case SPEEDSTEP_CPU_PIII_T: |
410 | case SPEEDSTEP_CPU_PIII_C: |
411 | case SPEEDSTEP_CPU_PIII_C_EARLY: |
412 | break; |
413 | default: |
414 | speedstep_processor = 0; |
415 | } |
416 | |
417 | if (!speedstep_processor) { |
418 | pr_debug("No supported Intel CPU detected.\n"); |
419 | return -ENODEV; |
420 | } |
421 | |
422 | pr_debug("signature:0x%.8ulx, command:0x%.8ulx, " |
423 | "event:0x%.8ulx, perf_level:0x%.8ulx.\n", |
424 | ist_info.signature, ist_info.command, |
425 | ist_info.event, ist_info.perf_level); |
426 | |
427 | /* Error if no IST-SMI BIOS or no PARM |
428 | sig= 'ISGE' aka 'Intel Speedstep Gate E' */ |
429 | if ((ist_info.signature != 0x47534943) && ( |
430 | (smi_port == 0) || (smi_cmd == 0))) |
431 | return -ENODEV; |
432 | |
433 | if (smi_sig == 1) |
434 | smi_sig = 0x47534943; |
435 | else |
436 | smi_sig = ist_info.signature; |
437 | |
438 | /* setup smi_port from MODLULE_PARM or BIOS */ |
439 | if ((smi_port > 0xff) || (smi_port < 0)) |
440 | return -EINVAL; |
441 | else if (smi_port == 0) |
442 | smi_port = ist_info.command & 0xff; |
443 | |
444 | if ((smi_cmd > 0xff) || (smi_cmd < 0)) |
445 | return -EINVAL; |
446 | else if (smi_cmd == 0) |
447 | smi_cmd = (ist_info.command >> 16) & 0xff; |
448 | |
449 | return cpufreq_register_driver(&speedstep_driver); |
450 | } |
451 | |
452 | |
453 | /** |
454 | * speedstep_exit - unregisters SpeedStep support |
455 | * |
456 | * Unregisters SpeedStep support. |
457 | */ |
458 | static void __exit speedstep_exit(void) |
459 | { |
460 | cpufreq_unregister_driver(&speedstep_driver); |
461 | } |
462 | |
463 | module_param(smi_port, int, 0444); |
464 | module_param(smi_cmd, int, 0444); |
465 | module_param(smi_sig, uint, 0444); |
466 | |
467 | MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value " |
468 | "-- Intel's default setting is 0xb2"); |
469 | MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value " |
470 | "-- Intel's default setting is 0x82"); |
471 | MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the " |
472 | "SMI interface."); |
473 | |
474 | MODULE_AUTHOR("Hiroshi Miura"); |
475 | MODULE_DESCRIPTION("Speedstep driver for IST applet SMI interface."); |
476 | MODULE_LICENSE("GPL"); |
477 | |
478 | module_init(speedstep_init); |
479 | module_exit(speedstep_exit); |
480 |
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