2 * Intel SpeedStep SMI driver.
4 * (C) 2003 Hiroshi Miura <miura@da-cha.org>
6 * Licensed under the terms of the GNU GPL License version 2.
11 /*********************************************************************
12 * SPEEDSTEP - DEFINITIONS *
13 *********************************************************************/
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/slab.h>
21 #include <linux/delay.h>
25 #include "speedstep-lib.h"
27 /* speedstep system management interface port/command.
29 * These parameters are got from IST-SMI BIOS call.
30 * If user gives it, these are used.
35 static unsigned int smi_sig
;
37 /* info about the processor */
38 static unsigned int speedstep_processor
;
41 * There are only two frequency states for each processor. Values
42 * are in kHz for the time being.
44 static struct cpufreq_frequency_table speedstep_freqs
[] = {
47 {0, CPUFREQ_TABLE_END
},
50 #define GET_SPEEDSTEP_OWNER 0
51 #define GET_SPEEDSTEP_STATE 1
52 #define SET_SPEEDSTEP_STATE 2
53 #define GET_SPEEDSTEP_FREQS 4
55 /* how often shall the SMI call be tried if it failed, e.g. because
56 * of DMA activity going on? */
59 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, \
63 * speedstep_smi_ownership
65 static int speedstep_smi_ownership(void)
67 u32 command
, result
, magic
, dummy
;
68 u32 function
= GET_SPEEDSTEP_OWNER
;
69 unsigned char magic_data
[] = "Copyright (c) 1999 Intel Corporation";
71 command
= (smi_sig
& 0xffffff00) | (smi_cmd
& 0xff);
72 magic
= virt_to_phys(magic_data
);
74 dprintk("trying to obtain ownership with command %x at port %x\n",
82 "=a" (dummy
), "=b" (dummy
), "=c" (dummy
), "=d" (dummy
),
84 : "a" (command
), "b" (function
), "c" (0), "d" (smi_port
),
89 dprintk("result is %x\n", result
);
95 * speedstep_smi_get_freqs - get SpeedStep preferred & current freq.
96 * @low: the low frequency value is placed here
97 * @high: the high frequency value is placed here
99 * Only available on later SpeedStep-enabled systems, returns false results or
100 * even hangs [cf. bugme.osdl.org # 1422] on earlier systems. Empirical testing
101 * shows that the latter occurs if !(ist_info.event & 0xFFFF).
103 static int speedstep_smi_get_freqs(unsigned int *low
, unsigned int *high
)
105 u32 command
, result
= 0, edi
, high_mhz
, low_mhz
, dummy
;
107 u32 function
= GET_SPEEDSTEP_FREQS
;
109 if (!(ist_info
.event
& 0xFFFF)) {
110 dprintk("bug #1422 -- can't read freqs from BIOS\n");
114 command
= (smi_sig
& 0xffffff00) | (smi_cmd
& 0xff);
116 dprintk("trying to determine frequencies with command %x at port %x\n",
119 __asm__
__volatile__(
126 "=d" (state
), "=D" (edi
), "=S" (dummy
)
130 "d" (smi_port
), "S" (0), "D" (0)
133 dprintk("result %x, low_freq %u, high_freq %u\n",
134 result
, low_mhz
, high_mhz
);
136 /* abort if results are obviously incorrect... */
137 if ((high_mhz
+ low_mhz
) < 600)
140 *high
= high_mhz
* 1000;
141 *low
= low_mhz
* 1000;
147 * speedstep_get_state - set the SpeedStep state
148 * @state: processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
151 static int speedstep_get_state(void)
153 u32 function
= GET_SPEEDSTEP_STATE
;
154 u32 result
, state
, edi
, command
, dummy
;
156 command
= (smi_sig
& 0xffffff00) | (smi_cmd
& 0xff);
158 dprintk("trying to determine current setting with command %x "
159 "at port %x\n", command
, smi_port
);
161 __asm__
__volatile__(
166 "=b" (state
), "=D" (edi
),
167 "=c" (dummy
), "=d" (dummy
), "=S" (dummy
)
168 : "a" (command
), "b" (function
), "c" (0),
169 "d" (smi_port
), "S" (0), "D" (0)
172 dprintk("state is %x, result is %x\n", state
, result
);
179 * speedstep_set_state - set the SpeedStep state
180 * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
183 static void speedstep_set_state(unsigned int state
)
185 unsigned int result
= 0, command
, new_state
, dummy
;
187 unsigned int function
= SET_SPEEDSTEP_STATE
;
188 unsigned int retry
= 0;
194 local_irq_save(flags
);
196 command
= (smi_sig
& 0xffffff00) | (smi_cmd
& 0xff);
198 dprintk("trying to set frequency to state %u "
199 "with command %x at port %x\n",
200 state
, command
, smi_port
);
204 dprintk("retry %u, previous result %u, waiting...\n",
209 __asm__
__volatile__(
213 : "=b" (new_state
), "=D" (result
),
214 "=c" (dummy
), "=a" (dummy
),
215 "=d" (dummy
), "=S" (dummy
)
216 : "a" (command
), "b" (function
), "c" (state
),
217 "d" (smi_port
), "S" (0), "D" (0)
219 } while ((new_state
!= state
) && (retry
<= SMI_TRIES
));
222 local_irq_restore(flags
);
224 if (new_state
== state
)
225 dprintk("change to %u MHz succeeded after %u tries "
227 (speedstep_freqs
[new_state
].frequency
/ 1000),
230 printk(KERN_ERR
"cpufreq: change to state %u "
231 "failed with new_state %u and result %u\n",
232 state
, new_state
, result
);
239 * speedstep_target - set a new CPUFreq policy
240 * @policy: new policy
241 * @target_freq: new freq
244 * Sets a new CPUFreq policy/freq.
246 static int speedstep_target(struct cpufreq_policy
*policy
,
247 unsigned int target_freq
, unsigned int relation
)
249 unsigned int newstate
= 0;
250 struct cpufreq_freqs freqs
;
252 if (cpufreq_frequency_table_target(policy
, &speedstep_freqs
[0],
253 target_freq
, relation
, &newstate
))
256 freqs
.old
= speedstep_freqs
[speedstep_get_state()].frequency
;
257 freqs
.new = speedstep_freqs
[newstate
].frequency
;
258 freqs
.cpu
= 0; /* speedstep.c is UP only driver */
260 if (freqs
.old
== freqs
.new)
263 cpufreq_notify_transition(&freqs
, CPUFREQ_PRECHANGE
);
264 speedstep_set_state(newstate
);
265 cpufreq_notify_transition(&freqs
, CPUFREQ_POSTCHANGE
);
272 * speedstep_verify - verifies a new CPUFreq policy
273 * @policy: new policy
275 * Limit must be within speedstep_low_freq and speedstep_high_freq, with
276 * at least one border included.
278 static int speedstep_verify(struct cpufreq_policy
*policy
)
280 return cpufreq_frequency_table_verify(policy
, &speedstep_freqs
[0]);
284 static int speedstep_cpu_init(struct cpufreq_policy
*policy
)
287 unsigned int speed
, state
;
288 unsigned int *low
, *high
;
290 /* capability check */
291 if (policy
->cpu
!= 0)
294 result
= speedstep_smi_ownership();
296 dprintk("fails in aquiring ownership of a SMI interface.\n");
300 /* detect low and high frequency */
301 low
= &speedstep_freqs
[SPEEDSTEP_LOW
].frequency
;
302 high
= &speedstep_freqs
[SPEEDSTEP_HIGH
].frequency
;
304 result
= speedstep_smi_get_freqs(low
, high
);
306 /* fall back to speedstep_lib.c dection mechanism:
307 * try both states out */
308 dprintk("could not detect low and high frequencies "
310 result
= speedstep_get_freqs(speedstep_processor
,
313 &speedstep_set_state
);
316 dprintk("could not detect two different speeds"
320 dprintk("workaround worked.\n");
323 /* get current speed setting */
324 state
= speedstep_get_state();
325 speed
= speedstep_freqs
[state
].frequency
;
327 dprintk("currently at %s speed setting - %i MHz\n",
328 (speed
== speedstep_freqs
[SPEEDSTEP_LOW
].frequency
)
332 /* cpuinfo and default policy values */
333 policy
->cpuinfo
.transition_latency
= CPUFREQ_ETERNAL
;
336 result
= cpufreq_frequency_table_cpuinfo(policy
, speedstep_freqs
);
340 cpufreq_frequency_table_get_attr(speedstep_freqs
, policy
->cpu
);
345 static int speedstep_cpu_exit(struct cpufreq_policy
*policy
)
347 cpufreq_frequency_table_put_attr(policy
->cpu
);
351 static unsigned int speedstep_get(unsigned int cpu
)
355 return speedstep_get_frequency(speedstep_processor
);
359 static int speedstep_resume(struct cpufreq_policy
*policy
)
361 int result
= speedstep_smi_ownership();
364 dprintk("fails in re-aquiring ownership of a SMI interface.\n");
369 static struct freq_attr
*speedstep_attr
[] = {
370 &cpufreq_freq_attr_scaling_available_freqs
,
374 static struct cpufreq_driver speedstep_driver
= {
375 .name
= "speedstep-smi",
376 .verify
= speedstep_verify
,
377 .target
= speedstep_target
,
378 .init
= speedstep_cpu_init
,
379 .exit
= speedstep_cpu_exit
,
380 .get
= speedstep_get
,
381 .resume
= speedstep_resume
,
382 .owner
= THIS_MODULE
,
383 .attr
= speedstep_attr
,
387 * speedstep_init - initializes the SpeedStep CPUFreq driver
389 * Initializes the SpeedStep support. Returns -ENODEV on unsupported
390 * BIOS, -EINVAL on problems during initiatization, and zero on
393 static int __init
speedstep_init(void)
395 speedstep_processor
= speedstep_detect_processor();
397 switch (speedstep_processor
) {
398 case SPEEDSTEP_CPU_PIII_T
:
399 case SPEEDSTEP_CPU_PIII_C
:
400 case SPEEDSTEP_CPU_PIII_C_EARLY
:
403 speedstep_processor
= 0;
406 if (!speedstep_processor
) {
407 dprintk("No supported Intel CPU detected.\n");
411 dprintk("signature:0x%.8lx, command:0x%.8lx, "
412 "event:0x%.8lx, perf_level:0x%.8lx.\n",
413 ist_info
.signature
, ist_info
.command
,
414 ist_info
.event
, ist_info
.perf_level
);
416 /* Error if no IST-SMI BIOS or no PARM
417 sig= 'ISGE' aka 'Intel Speedstep Gate E' */
418 if ((ist_info
.signature
!= 0x47534943) && (
419 (smi_port
== 0) || (smi_cmd
== 0)))
423 smi_sig
= 0x47534943;
425 smi_sig
= ist_info
.signature
;
427 /* setup smi_port from MODLULE_PARM or BIOS */
428 if ((smi_port
> 0xff) || (smi_port
< 0))
430 else if (smi_port
== 0)
431 smi_port
= ist_info
.command
& 0xff;
433 if ((smi_cmd
> 0xff) || (smi_cmd
< 0))
435 else if (smi_cmd
== 0)
436 smi_cmd
= (ist_info
.command
>> 16) & 0xff;
438 return cpufreq_register_driver(&speedstep_driver
);
443 * speedstep_exit - unregisters SpeedStep support
445 * Unregisters SpeedStep support.
447 static void __exit
speedstep_exit(void)
449 cpufreq_unregister_driver(&speedstep_driver
);
452 module_param(smi_port
, int, 0444);
453 module_param(smi_cmd
, int, 0444);
454 module_param(smi_sig
, uint
, 0444);
456 MODULE_PARM_DESC(smi_port
, "Override the BIOS-given IST port with this value "
457 "-- Intel's default setting is 0xb2");
458 MODULE_PARM_DESC(smi_cmd
, "Override the BIOS-given IST command with this value "
459 "-- Intel's default setting is 0x82");
460 MODULE_PARM_DESC(smi_sig
, "Set to 1 to fake the IST signature when using the "
463 MODULE_AUTHOR("Hiroshi Miura");
464 MODULE_DESCRIPTION("Speedstep driver for IST applet SMI interface.");
465 MODULE_LICENSE("GPL");
467 module_init(speedstep_init
);
468 module_exit(speedstep_exit
);