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/delay.h>
23 #include <asm/cpu_device_id.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 enum speedstep_processor 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? */
60 * speedstep_smi_ownership
62 static int speedstep_smi_ownership(void)
64 u32 command
, result
, magic
, dummy
;
65 u32 function
= GET_SPEEDSTEP_OWNER
;
66 unsigned char magic_data
[] = "Copyright (c) 1999 Intel Corporation";
68 command
= (smi_sig
& 0xffffff00) | (smi_cmd
& 0xff);
69 magic
= virt_to_phys(magic_data
);
71 pr_debug("trying to obtain ownership with command %x at port %x\n",
79 "=a" (dummy
), "=b" (dummy
), "=c" (dummy
), "=d" (dummy
),
81 : "a" (command
), "b" (function
), "c" (0), "d" (smi_port
),
86 pr_debug("result is %x\n", result
);
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
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).
100 static int speedstep_smi_get_freqs(unsigned int *low
, unsigned int *high
)
102 u32 command
, result
= 0, edi
, high_mhz
, low_mhz
, dummy
;
104 u32 function
= GET_SPEEDSTEP_FREQS
;
106 if (!(ist_info
.event
& 0xFFFF)) {
107 pr_debug("bug #1422 -- can't read freqs from BIOS\n");
111 command
= (smi_sig
& 0xffffff00) | (smi_cmd
& 0xff);
113 pr_debug("trying to determine frequencies with command %x at port %x\n",
116 __asm__
__volatile__(
123 "=d" (state
), "=D" (edi
), "=S" (dummy
)
127 "d" (smi_port
), "S" (0), "D" (0)
130 pr_debug("result %x, low_freq %u, high_freq %u\n",
131 result
, low_mhz
, high_mhz
);
133 /* abort if results are obviously incorrect... */
134 if ((high_mhz
+ low_mhz
) < 600)
137 *high
= high_mhz
* 1000;
138 *low
= low_mhz
* 1000;
144 * speedstep_get_state - set the SpeedStep state
145 * @state: processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
148 static int speedstep_get_state(void)
150 u32 function
= GET_SPEEDSTEP_STATE
;
151 u32 result
, state
, edi
, command
, dummy
;
153 command
= (smi_sig
& 0xffffff00) | (smi_cmd
& 0xff);
155 pr_debug("trying to determine current setting with command %x "
156 "at port %x\n", command
, smi_port
);
158 __asm__
__volatile__(
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)
169 pr_debug("state is %x, result is %x\n", state
, result
);
176 * speedstep_set_state - set the SpeedStep state
177 * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
180 static void speedstep_set_state(unsigned int state
)
182 unsigned int result
= 0, command
, new_state
, dummy
;
184 unsigned int function
= SET_SPEEDSTEP_STATE
;
185 unsigned int retry
= 0;
191 local_irq_save(flags
);
193 command
= (smi_sig
& 0xffffff00) | (smi_cmd
& 0xff);
195 pr_debug("trying to set frequency to state %u "
196 "with command %x at port %x\n",
197 state
, command
, smi_port
);
201 pr_debug("retry %u, previous result %u, waiting...\n",
206 __asm__
__volatile__(
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)
216 } while ((new_state
!= state
) && (retry
<= SMI_TRIES
));
219 local_irq_restore(flags
);
221 if (new_state
== state
)
222 pr_debug("change to %u MHz succeeded after %u tries "
224 (speedstep_freqs
[new_state
].frequency
/ 1000),
227 printk(KERN_ERR
"cpufreq: change to state %u "
228 "failed with new_state %u and result %u\n",
229 state
, new_state
, result
);
236 * speedstep_target - set a new CPUFreq policy
237 * @policy: new policy
238 * @target_freq: new freq
241 * Sets a new CPUFreq policy/freq.
243 static int speedstep_target(struct cpufreq_policy
*policy
,
244 unsigned int target_freq
, unsigned int relation
)
246 unsigned int newstate
= 0;
247 struct cpufreq_freqs freqs
;
249 if (cpufreq_frequency_table_target(policy
, &speedstep_freqs
[0],
250 target_freq
, relation
, &newstate
))
253 freqs
.old
= speedstep_freqs
[speedstep_get_state()].frequency
;
254 freqs
.new = speedstep_freqs
[newstate
].frequency
;
256 if (freqs
.old
== freqs
.new)
259 cpufreq_notify_transition(policy
, &freqs
, CPUFREQ_PRECHANGE
);
260 speedstep_set_state(newstate
);
261 cpufreq_notify_transition(policy
, &freqs
, CPUFREQ_POSTCHANGE
);
267 static int speedstep_cpu_init(struct cpufreq_policy
*policy
)
270 unsigned int speed
, state
;
271 unsigned int *low
, *high
;
273 /* capability check */
274 if (policy
->cpu
!= 0)
277 result
= speedstep_smi_ownership();
279 pr_debug("fails in acquiring ownership of a SMI interface.\n");
283 /* detect low and high frequency */
284 low
= &speedstep_freqs
[SPEEDSTEP_LOW
].frequency
;
285 high
= &speedstep_freqs
[SPEEDSTEP_HIGH
].frequency
;
287 result
= speedstep_smi_get_freqs(low
, high
);
289 /* fall back to speedstep_lib.c dection mechanism:
290 * try both states out */
291 pr_debug("could not detect low and high frequencies "
293 result
= speedstep_get_freqs(speedstep_processor
,
296 &speedstep_set_state
);
299 pr_debug("could not detect two different speeds"
303 pr_debug("workaround worked.\n");
306 /* get current speed setting */
307 state
= speedstep_get_state();
308 speed
= speedstep_freqs
[state
].frequency
;
310 pr_debug("currently at %s speed setting - %i MHz\n",
311 (speed
== speedstep_freqs
[SPEEDSTEP_LOW
].frequency
)
315 /* cpuinfo and default policy values */
316 policy
->cpuinfo
.transition_latency
= CPUFREQ_ETERNAL
;
319 return cpufreq_table_validate_and_show(policy
, speedstep_freqs
);
322 static unsigned int speedstep_get(unsigned int cpu
)
326 return speedstep_get_frequency(speedstep_processor
);
330 static int speedstep_resume(struct cpufreq_policy
*policy
)
332 int result
= speedstep_smi_ownership();
335 pr_debug("fails in re-acquiring ownership of a SMI interface.\n");
340 static struct cpufreq_driver speedstep_driver
= {
341 .name
= "speedstep-smi",
342 .verify
= cpufreq_generic_frequency_table_verify
,
343 .target
= speedstep_target
,
344 .init
= speedstep_cpu_init
,
345 .exit
= cpufreq_generic_exit
,
346 .get
= speedstep_get
,
347 .resume
= speedstep_resume
,
348 .attr
= cpufreq_generic_attr
,
351 static const struct x86_cpu_id ss_smi_ids
[] = {
352 { X86_VENDOR_INTEL
, 6, 0xb, },
353 { X86_VENDOR_INTEL
, 6, 0x8, },
354 { X86_VENDOR_INTEL
, 15, 2 },
358 /* Not auto loaded currently */
359 MODULE_DEVICE_TABLE(x86cpu
, ss_smi_ids
);
363 * speedstep_init - initializes the SpeedStep CPUFreq driver
365 * Initializes the SpeedStep support. Returns -ENODEV on unsupported
366 * BIOS, -EINVAL on problems during initiatization, and zero on
369 static int __init
speedstep_init(void)
371 if (!x86_match_cpu(ss_smi_ids
))
374 speedstep_processor
= speedstep_detect_processor();
376 switch (speedstep_processor
) {
377 case SPEEDSTEP_CPU_PIII_T
:
378 case SPEEDSTEP_CPU_PIII_C
:
379 case SPEEDSTEP_CPU_PIII_C_EARLY
:
382 speedstep_processor
= 0;
385 if (!speedstep_processor
) {
386 pr_debug("No supported Intel CPU detected.\n");
390 pr_debug("signature:0x%.8ulx, command:0x%.8ulx, "
391 "event:0x%.8ulx, perf_level:0x%.8ulx.\n",
392 ist_info
.signature
, ist_info
.command
,
393 ist_info
.event
, ist_info
.perf_level
);
395 /* Error if no IST-SMI BIOS or no PARM
396 sig= 'ISGE' aka 'Intel Speedstep Gate E' */
397 if ((ist_info
.signature
!= 0x47534943) && (
398 (smi_port
== 0) || (smi_cmd
== 0)))
402 smi_sig
= 0x47534943;
404 smi_sig
= ist_info
.signature
;
406 /* setup smi_port from MODLULE_PARM or BIOS */
407 if ((smi_port
> 0xff) || (smi_port
< 0))
409 else if (smi_port
== 0)
410 smi_port
= ist_info
.command
& 0xff;
412 if ((smi_cmd
> 0xff) || (smi_cmd
< 0))
414 else if (smi_cmd
== 0)
415 smi_cmd
= (ist_info
.command
>> 16) & 0xff;
417 return cpufreq_register_driver(&speedstep_driver
);
422 * speedstep_exit - unregisters SpeedStep support
424 * Unregisters SpeedStep support.
426 static void __exit
speedstep_exit(void)
428 cpufreq_unregister_driver(&speedstep_driver
);
431 module_param(smi_port
, int, 0444);
432 module_param(smi_cmd
, int, 0444);
433 module_param(smi_sig
, uint
, 0444);
435 MODULE_PARM_DESC(smi_port
, "Override the BIOS-given IST port with this value "
436 "-- Intel's default setting is 0xb2");
437 MODULE_PARM_DESC(smi_cmd
, "Override the BIOS-given IST command with this value "
438 "-- Intel's default setting is 0x82");
439 MODULE_PARM_DESC(smi_sig
, "Set to 1 to fake the IST signature when using the "
442 MODULE_AUTHOR("Hiroshi Miura");
443 MODULE_DESCRIPTION("Speedstep driver for IST applet SMI interface.");
444 MODULE_LICENSE("GPL");
446 module_init(speedstep_init
);
447 module_exit(speedstep_exit
);