Merge remote-tracking branch 'origin/dev/sumit-linux-3.10.96' into TOT-merge
[linux-3.10.git] / drivers / cpufreq / speedstep-smi.c
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         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  */
255 static 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  */
287 static int speedstep_verify(struct cpufreq_policy *policy)
288 {
289         return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
290 }
291
292
293 static 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
354 static int speedstep_cpu_exit(struct cpufreq_policy *policy)
355 {
356         cpufreq_frequency_table_put_attr(policy->cpu);
357         return 0;
358 }
359
360 static unsigned int speedstep_get(unsigned int cpu)
361 {
362         if (cpu)
363                 return -ENODEV;
364         return speedstep_get_frequency(speedstep_processor);
365 }
366
367
368 static 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
378 static struct freq_attr *speedstep_attr[] = {
379         &cpufreq_freq_attr_scaling_available_freqs,
380         NULL,
381 };
382
383 static 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
395 static 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 */
403 MODULE_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  */
413 static 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  */
470 static void __exit speedstep_exit(void)
471 {
472         cpufreq_unregister_driver(&speedstep_driver);
473 }
474
475 module_param(smi_port, int, 0444);
476 module_param(smi_cmd,  int, 0444);
477 module_param(smi_sig, uint, 0444);
478
479 MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value "
480                 "-- Intel's default setting is 0xb2");
481 MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value "
482                 "-- Intel's default setting is 0x82");
483 MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the "
484                 "SMI interface.");
485
486 MODULE_AUTHOR("Hiroshi Miura");
487 MODULE_DESCRIPTION("Speedstep driver for IST applet SMI interface.");
488 MODULE_LICENSE("GPL");
489
490 module_init(speedstep_init);
491 module_exit(speedstep_exit);