blob: b01926df5b1b07797cbc4d1f6b953a4e2502b4bb [file] [log] [blame]
lh9ed821d2023-04-07 01:36:19 -07001/*
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 */
33static int smi_port;
34static int smi_cmd;
35static unsigned int smi_sig;
36
37/* info about the processor */
38static 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 */
44static 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 */
62static 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 */
100static 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 */
148static 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 */
180static 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 preempt_disable();
192 local_irq_save(flags);
193
194 command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
195
196 pr_debug("trying to set frequency to state %u "
197 "with command %x at port %x\n",
198 state, command, smi_port);
199
200 do {
201 if (retry) {
202 /*
203 * We need to enable interrupts, otherwise the blockage
204 * won't resolve.
205 *
206 * We disable preemption so that other processes don't
207 * run. If other processes were running, they could
208 * submit more DMA requests, making the blockage worse.
209 */
210 pr_debug("retry %u, previous result %u, waiting...\n",
211 retry, result);
212 local_irq_enable();
213 mdelay(retry * 50);
214 local_irq_disable();
215 }
216 retry++;
217 __asm__ __volatile__(
218 "push %%ebp\n"
219 "out %%al, (%%dx)\n"
220 "pop %%ebp"
221 : "=b" (new_state), "=D" (result),
222 "=c" (dummy), "=a" (dummy),
223 "=d" (dummy), "=S" (dummy)
224 : "a" (command), "b" (function), "c" (state),
225 "d" (smi_port), "S" (0), "D" (0)
226 );
227 } while ((new_state != state) && (retry <= SMI_TRIES));
228
229 /* enable IRQs */
230 local_irq_restore(flags);
231 preempt_enable();
232
233 if (new_state == state)
234 pr_debug("change to %u MHz succeeded after %u tries "
235 "with result %u\n",
236 (speedstep_freqs[new_state].frequency / 1000),
237 retry, result);
238 else
239 printk(KERN_ERR "cpufreq: change to state %u "
240 "failed with new_state %u and result %u\n",
241 state, new_state, result);
242
243 return;
244}
245
246
247/**
248 * speedstep_target - set a new CPUFreq policy
249 * @policy: new policy
250 * @target_freq: new freq
251 * @relation:
252 *
253 * Sets a new CPUFreq policy/freq.
254 */
255static int speedstep_target(struct cpufreq_policy *policy,
256 unsigned int target_freq, unsigned int relation)
257{
258 unsigned int newstate = 0;
259 struct cpufreq_freqs freqs;
260
261 if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0],
262 target_freq, relation, &newstate))
263 return -EINVAL;
264
265 freqs.old = speedstep_freqs[speedstep_get_state()].frequency;
266 freqs.new = speedstep_freqs[newstate].frequency;
267 freqs.cpu = 0; /* speedstep.c is UP only driver */
268
269 if (freqs.old == freqs.new)
270 return 0;
271
272 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
273 speedstep_set_state(newstate);
274 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
275
276 return 0;
277}
278
279
280/**
281 * speedstep_verify - verifies a new CPUFreq policy
282 * @policy: new policy
283 *
284 * Limit must be within speedstep_low_freq and speedstep_high_freq, with
285 * at least one border included.
286 */
287static int speedstep_verify(struct cpufreq_policy *policy)
288{
289 return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
290}
291
292
293static int speedstep_cpu_init(struct cpufreq_policy *policy)
294{
295 int result;
296 unsigned int speed, state;
297 unsigned int *low, *high;
298
299 /* capability check */
300 if (policy->cpu != 0)
301 return -ENODEV;
302
303 result = speedstep_smi_ownership();
304 if (result) {
305 pr_debug("fails in acquiring ownership of a SMI interface.\n");
306 return -EINVAL;
307 }
308
309 /* detect low and high frequency */
310 low = &speedstep_freqs[SPEEDSTEP_LOW].frequency;
311 high = &speedstep_freqs[SPEEDSTEP_HIGH].frequency;
312
313 result = speedstep_smi_get_freqs(low, high);
314 if (result) {
315 /* fall back to speedstep_lib.c dection mechanism:
316 * try both states out */
317 pr_debug("could not detect low and high frequencies "
318 "by SMI call.\n");
319 result = speedstep_get_freqs(speedstep_processor,
320 low, high,
321 NULL,
322 &speedstep_set_state);
323
324 if (result) {
325 pr_debug("could not detect two different speeds"
326 " -- aborting.\n");
327 return result;
328 } else
329 pr_debug("workaround worked.\n");
330 }
331
332 /* get current speed setting */
333 state = speedstep_get_state();
334 speed = speedstep_freqs[state].frequency;
335
336 pr_debug("currently at %s speed setting - %i MHz\n",
337 (speed == speedstep_freqs[SPEEDSTEP_LOW].frequency)
338 ? "low" : "high",
339 (speed / 1000));
340
341 /* cpuinfo and default policy values */
342 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
343 policy->cur = speed;
344
345 result = cpufreq_frequency_table_cpuinfo(policy, speedstep_freqs);
346 if (result)
347 return result;
348
349 cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu);
350
351 return 0;
352}
353
354static int speedstep_cpu_exit(struct cpufreq_policy *policy)
355{
356 cpufreq_frequency_table_put_attr(policy->cpu);
357 return 0;
358}
359
360static unsigned int speedstep_get(unsigned int cpu)
361{
362 if (cpu)
363 return -ENODEV;
364 return speedstep_get_frequency(speedstep_processor);
365}
366
367
368static int speedstep_resume(struct cpufreq_policy *policy)
369{
370 int result = speedstep_smi_ownership();
371
372 if (result)
373 pr_debug("fails in re-acquiring ownership of a SMI interface.\n");
374
375 return result;
376}
377
378static struct freq_attr *speedstep_attr[] = {
379 &cpufreq_freq_attr_scaling_available_freqs,
380 NULL,
381};
382
383static struct cpufreq_driver speedstep_driver = {
384 .name = "speedstep-smi",
385 .verify = speedstep_verify,
386 .target = speedstep_target,
387 .init = speedstep_cpu_init,
388 .exit = speedstep_cpu_exit,
389 .get = speedstep_get,
390 .resume = speedstep_resume,
391 .owner = THIS_MODULE,
392 .attr = speedstep_attr,
393};
394
395static const struct x86_cpu_id ss_smi_ids[] = {
396 { X86_VENDOR_INTEL, 6, 0xb, },
397 { X86_VENDOR_INTEL, 6, 0x8, },
398 { X86_VENDOR_INTEL, 15, 2 },
399 {}
400};
401#if 0
402/* Not auto loaded currently */
403MODULE_DEVICE_TABLE(x86cpu, ss_smi_ids);
404#endif
405
406/**
407 * speedstep_init - initializes the SpeedStep CPUFreq driver
408 *
409 * Initializes the SpeedStep support. Returns -ENODEV on unsupported
410 * BIOS, -EINVAL on problems during initiatization, and zero on
411 * success.
412 */
413static int __init speedstep_init(void)
414{
415 if (!x86_match_cpu(ss_smi_ids))
416 return -ENODEV;
417
418 speedstep_processor = speedstep_detect_processor();
419
420 switch (speedstep_processor) {
421 case SPEEDSTEP_CPU_PIII_T:
422 case SPEEDSTEP_CPU_PIII_C:
423 case SPEEDSTEP_CPU_PIII_C_EARLY:
424 break;
425 default:
426 speedstep_processor = 0;
427 }
428
429 if (!speedstep_processor) {
430 pr_debug("No supported Intel CPU detected.\n");
431 return -ENODEV;
432 }
433
434 pr_debug("signature:0x%.8ulx, command:0x%.8ulx, "
435 "event:0x%.8ulx, perf_level:0x%.8ulx.\n",
436 ist_info.signature, ist_info.command,
437 ist_info.event, ist_info.perf_level);
438
439 /* Error if no IST-SMI BIOS or no PARM
440 sig= 'ISGE' aka 'Intel Speedstep Gate E' */
441 if ((ist_info.signature != 0x47534943) && (
442 (smi_port == 0) || (smi_cmd == 0)))
443 return -ENODEV;
444
445 if (smi_sig == 1)
446 smi_sig = 0x47534943;
447 else
448 smi_sig = ist_info.signature;
449
450 /* setup smi_port from MODLULE_PARM or BIOS */
451 if ((smi_port > 0xff) || (smi_port < 0))
452 return -EINVAL;
453 else if (smi_port == 0)
454 smi_port = ist_info.command & 0xff;
455
456 if ((smi_cmd > 0xff) || (smi_cmd < 0))
457 return -EINVAL;
458 else if (smi_cmd == 0)
459 smi_cmd = (ist_info.command >> 16) & 0xff;
460
461 return cpufreq_register_driver(&speedstep_driver);
462}
463
464
465/**
466 * speedstep_exit - unregisters SpeedStep support
467 *
468 * Unregisters SpeedStep support.
469 */
470static void __exit speedstep_exit(void)
471{
472 cpufreq_unregister_driver(&speedstep_driver);
473}
474
475module_param(smi_port, int, 0444);
476module_param(smi_cmd, int, 0444);
477module_param(smi_sig, uint, 0444);
478
479MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value "
480 "-- Intel's default setting is 0xb2");
481MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value "
482 "-- Intel's default setting is 0x82");
483MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the "
484 "SMI interface.");
485
486MODULE_AUTHOR("Hiroshi Miura");
487MODULE_DESCRIPTION("Speedstep driver for IST applet SMI interface.");
488MODULE_LICENSE("GPL");
489
490module_init(speedstep_init);
491module_exit(speedstep_exit);