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 */
speedstep_smi_ownership(void)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 */
speedstep_smi_get_freqs(unsigned int * low,unsigned int * high)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 */
speedstep_get_state(void)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 */
speedstep_set_state(unsigned int state)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 */
speedstep_target(struct cpufreq_policy * policy,unsigned int target_freq,unsigned int relation)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 */
speedstep_verify(struct cpufreq_policy * policy)275 static int speedstep_verify(struct cpufreq_policy *policy)
276 {
277 return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
278 }
279
280
speedstep_cpu_init(struct cpufreq_policy * policy)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
speedstep_cpu_exit(struct cpufreq_policy * policy)342 static int speedstep_cpu_exit(struct cpufreq_policy *policy)
343 {
344 cpufreq_frequency_table_put_attr(policy->cpu);
345 return 0;
346 }
347
speedstep_get(unsigned int cpu)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
speedstep_resume(struct cpufreq_policy * policy)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 */
speedstep_init(void)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 */
speedstep_exit(void)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