2 * processor_throttling.c - Throttling submodule of the ACPI processor driver
4 * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
5 * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
6 * Copyright (C) 2004 Dominik Brodowski <linux@brodo.de>
7 * Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
8 * - Added processor hotplug support
10 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or (at
15 * your option) any later version.
17 * This program is distributed in the hope that it will be useful, but
18 * WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * General Public License for more details.
22 * You should have received a copy of the GNU General Public License along
23 * with this program; if not, write to the Free Software Foundation, Inc.,
24 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
26 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
29 #include <linux/kernel.h>
30 #include <linux/module.h>
31 #include <linux/init.h>
32 #include <linux/cpufreq.h>
33 #include <linux/proc_fs.h>
34 #include <linux/seq_file.h>
37 #include <asm/uaccess.h>
39 #include <acpi/acpi_bus.h>
40 #include <acpi/processor.h>
42 #define ACPI_PROCESSOR_COMPONENT 0x01000000
43 #define ACPI_PROCESSOR_CLASS "processor"
44 #define _COMPONENT ACPI_PROCESSOR_COMPONENT
45 ACPI_MODULE_NAME("processor_throttling");
47 static int acpi_processor_get_throttling(struct acpi_processor
*pr
);
48 int acpi_processor_set_throttling(struct acpi_processor
*pr
, int state
);
50 static int acpi_processor_get_platform_limit(struct acpi_processor
*pr
)
52 acpi_status status
= 0;
53 unsigned long tpc
= 0;
57 status
= acpi_evaluate_integer(pr
->handle
, "_TPC", NULL
, &tpc
);
58 if (ACPI_FAILURE(status
) && status
!= AE_NOT_FOUND
) {
59 ACPI_EXCEPTION((AE_INFO
, status
, "Evaluating _TPC"));
62 pr
->throttling_platform_limit
= (int)tpc
;
66 int acpi_processor_tstate_has_changed(struct acpi_processor
*pr
)
68 return acpi_processor_get_platform_limit(pr
);
71 /* --------------------------------------------------------------------------
72 _PTC, _TSS, _TSD support
73 -------------------------------------------------------------------------- */
74 static int acpi_processor_get_throttling_control(struct acpi_processor
*pr
)
77 acpi_status status
= 0;
78 struct acpi_buffer buffer
= { ACPI_ALLOCATE_BUFFER
, NULL
};
79 union acpi_object
*ptc
= NULL
;
80 union acpi_object obj
= { 0 };
82 status
= acpi_evaluate_object(pr
->handle
, "_PTC", NULL
, &buffer
);
83 if (ACPI_FAILURE(status
)) {
84 ACPI_EXCEPTION((AE_INFO
, status
, "Evaluating _PTC"));
88 ptc
= (union acpi_object
*)buffer
.pointer
;
89 if (!ptc
|| (ptc
->type
!= ACPI_TYPE_PACKAGE
)
90 || (ptc
->package
.count
!= 2)) {
91 printk(KERN_ERR PREFIX
"Invalid _PTC data\n");
100 obj
= ptc
->package
.elements
[0];
102 if ((obj
.type
!= ACPI_TYPE_BUFFER
)
103 || (obj
.buffer
.length
< sizeof(struct acpi_ptc_register
))
104 || (obj
.buffer
.pointer
== NULL
)) {
105 printk(KERN_ERR PREFIX
106 "Invalid _PTC data (control_register)\n");
110 memcpy(&pr
->throttling
.control_register
, obj
.buffer
.pointer
,
111 sizeof(struct acpi_ptc_register
));
117 obj
= ptc
->package
.elements
[1];
119 if ((obj
.type
!= ACPI_TYPE_BUFFER
)
120 || (obj
.buffer
.length
< sizeof(struct acpi_ptc_register
))
121 || (obj
.buffer
.pointer
== NULL
)) {
122 printk(KERN_ERR PREFIX
"Invalid _PTC data (status_register)\n");
127 memcpy(&pr
->throttling
.status_register
, obj
.buffer
.pointer
,
128 sizeof(struct acpi_ptc_register
));
131 kfree(buffer
.pointer
);
135 static int acpi_processor_get_throttling_states(struct acpi_processor
*pr
)
138 acpi_status status
= AE_OK
;
139 struct acpi_buffer buffer
= { ACPI_ALLOCATE_BUFFER
, NULL
};
140 struct acpi_buffer format
= { sizeof("NNNNN"), "NNNNN" };
141 struct acpi_buffer state
= { 0, NULL
};
142 union acpi_object
*tss
= NULL
;
145 status
= acpi_evaluate_object(pr
->handle
, "_TSS", NULL
, &buffer
);
146 if (ACPI_FAILURE(status
)) {
147 ACPI_EXCEPTION((AE_INFO
, status
, "Evaluating _TSS"));
151 tss
= buffer
.pointer
;
152 if (!tss
|| (tss
->type
!= ACPI_TYPE_PACKAGE
)) {
153 printk(KERN_ERR PREFIX
"Invalid _TSS data\n");
158 ACPI_DEBUG_PRINT((ACPI_DB_INFO
, "Found %d throttling states\n",
159 tss
->package
.count
));
161 pr
->throttling
.state_count
= tss
->package
.count
;
162 pr
->throttling
.states_tss
=
163 kmalloc(sizeof(struct acpi_processor_tx_tss
) * tss
->package
.count
,
165 if (!pr
->throttling
.states_tss
) {
170 for (i
= 0; i
< pr
->throttling
.state_count
; i
++) {
172 struct acpi_processor_tx_tss
*tx
=
173 (struct acpi_processor_tx_tss
*)&(pr
->throttling
.
176 state
.length
= sizeof(struct acpi_processor_tx_tss
);
179 ACPI_DEBUG_PRINT((ACPI_DB_INFO
, "Extracting state %d\n", i
));
181 status
= acpi_extract_package(&(tss
->package
.elements
[i
]),
183 if (ACPI_FAILURE(status
)) {
184 ACPI_EXCEPTION((AE_INFO
, status
, "Invalid _TSS data"));
186 kfree(pr
->throttling
.states_tss
);
190 if (!tx
->freqpercentage
) {
191 printk(KERN_ERR PREFIX
192 "Invalid _TSS data: freq is zero\n");
194 kfree(pr
->throttling
.states_tss
);
200 kfree(buffer
.pointer
);
204 static int acpi_processor_get_tsd(struct acpi_processor
*pr
)
207 acpi_status status
= AE_OK
;
208 struct acpi_buffer buffer
= { ACPI_ALLOCATE_BUFFER
, NULL
};
209 struct acpi_buffer format
= { sizeof("NNNNN"), "NNNNN" };
210 struct acpi_buffer state
= { 0, NULL
};
211 union acpi_object
*tsd
= NULL
;
212 struct acpi_tsd_package
*pdomain
;
214 status
= acpi_evaluate_object(pr
->handle
, "_TSD", NULL
, &buffer
);
215 if (ACPI_FAILURE(status
)) {
219 tsd
= buffer
.pointer
;
220 if (!tsd
|| (tsd
->type
!= ACPI_TYPE_PACKAGE
)) {
221 ACPI_DEBUG_PRINT((ACPI_DB_ERROR
, "Invalid _TSD data\n"));
226 if (tsd
->package
.count
!= 1) {
227 ACPI_DEBUG_PRINT((ACPI_DB_ERROR
, "Invalid _TSD data\n"));
232 pdomain
= &(pr
->throttling
.domain_info
);
234 state
.length
= sizeof(struct acpi_tsd_package
);
235 state
.pointer
= pdomain
;
237 status
= acpi_extract_package(&(tsd
->package
.elements
[0]),
239 if (ACPI_FAILURE(status
)) {
240 ACPI_DEBUG_PRINT((ACPI_DB_ERROR
, "Invalid _TSD data\n"));
245 if (pdomain
->num_entries
!= ACPI_TSD_REV0_ENTRIES
) {
246 ACPI_DEBUG_PRINT((ACPI_DB_ERROR
, "Unknown _TSD:num_entries\n"));
251 if (pdomain
->revision
!= ACPI_TSD_REV0_REVISION
) {
252 ACPI_DEBUG_PRINT((ACPI_DB_ERROR
, "Unknown _TSD:revision\n"));
258 kfree(buffer
.pointer
);
262 /* --------------------------------------------------------------------------
264 -------------------------------------------------------------------------- */
265 static int acpi_processor_get_throttling_fadt(struct acpi_processor
*pr
)
275 if (!pr
->flags
.throttling
)
278 pr
->throttling
.state
= 0;
280 duty_mask
= pr
->throttling
.state_count
- 1;
282 duty_mask
<<= pr
->throttling
.duty_offset
;
286 value
= inl(pr
->throttling
.address
);
289 * Compute the current throttling state when throttling is enabled
293 duty_value
= value
& duty_mask
;
294 duty_value
>>= pr
->throttling
.duty_offset
;
297 state
= pr
->throttling
.state_count
- duty_value
;
300 pr
->throttling
.state
= state
;
304 ACPI_DEBUG_PRINT((ACPI_DB_INFO
,
305 "Throttling state is T%d (%d%% throttling applied)\n",
306 state
, pr
->throttling
.states
[state
].performance
));
311 static int acpi_read_throttling_status(struct acpi_processor_throttling
315 switch (throttling
->status_register
.space_id
) {
316 case ACPI_ADR_SPACE_SYSTEM_IO
:
317 acpi_os_read_port((acpi_io_address
) throttling
->status_register
.
319 (u32
) throttling
->status_register
.bit_width
*
322 case ACPI_ADR_SPACE_FIXED_HARDWARE
:
323 printk(KERN_ERR PREFIX
324 "HARDWARE addr space,NOT supported yet\n");
327 printk(KERN_ERR PREFIX
"Unknown addr space %d\n",
328 (u32
) (throttling
->status_register
.space_id
));
333 static int acpi_write_throttling_state(struct acpi_processor_throttling
334 *throttling
, int value
)
338 switch (throttling
->control_register
.space_id
) {
339 case ACPI_ADR_SPACE_SYSTEM_IO
:
340 acpi_os_write_port((acpi_io_address
) throttling
->
341 control_register
.address
, value
,
342 (u32
) throttling
->control_register
.
346 case ACPI_ADR_SPACE_FIXED_HARDWARE
:
347 printk(KERN_ERR PREFIX
348 "HARDWARE addr space,NOT supported yet\n");
351 printk(KERN_ERR PREFIX
"Unknown addr space %d\n",
352 (u32
) (throttling
->control_register
.space_id
));
357 static int acpi_get_throttling_state(struct acpi_processor
*pr
, int value
)
361 for (i
= 0; i
< pr
->throttling
.state_count
; i
++) {
362 struct acpi_processor_tx_tss
*tx
=
363 (struct acpi_processor_tx_tss
*)&(pr
->throttling
.
365 if (tx
->control
== value
)
368 if (i
> pr
->throttling
.state_count
)
373 static int acpi_get_throttling_value(struct acpi_processor
*pr
, int state
)
376 if (state
>= 0 && state
<= pr
->throttling
.state_count
) {
377 struct acpi_processor_tx_tss
*tx
=
378 (struct acpi_processor_tx_tss
*)&(pr
->throttling
.
385 static int acpi_processor_get_throttling_ptc(struct acpi_processor
*pr
)
393 if (!pr
->flags
.throttling
)
396 pr
->throttling
.state
= 0;
398 value
= acpi_read_throttling_status(&pr
->throttling
);
400 state
= acpi_get_throttling_state(pr
, value
);
401 pr
->throttling
.state
= state
;
408 static int acpi_processor_get_throttling(struct acpi_processor
*pr
)
410 return pr
->throttling
.acpi_processor_get_throttling(pr
);
413 static int acpi_processor_set_throttling_fadt(struct acpi_processor
*pr
,
423 if ((state
< 0) || (state
> (pr
->throttling
.state_count
- 1)))
426 if (!pr
->flags
.throttling
)
429 if (state
== pr
->throttling
.state
)
432 if (state
< pr
->throttling_platform_limit
)
435 * Calculate the duty_value and duty_mask.
438 duty_value
= pr
->throttling
.state_count
- state
;
440 duty_value
<<= pr
->throttling
.duty_offset
;
442 /* Used to clear all duty_value bits */
443 duty_mask
= pr
->throttling
.state_count
- 1;
445 duty_mask
<<= acpi_gbl_FADT
.duty_offset
;
446 duty_mask
= ~duty_mask
;
452 * Disable throttling by writing a 0 to bit 4. Note that we must
453 * turn it off before you can change the duty_value.
455 value
= inl(pr
->throttling
.address
);
458 outl(value
, pr
->throttling
.address
);
462 * Write the new duty_value and then enable throttling. Note
463 * that a state value of 0 leaves throttling disabled.
468 outl(value
, pr
->throttling
.address
);
471 outl(value
, pr
->throttling
.address
);
474 pr
->throttling
.state
= state
;
478 ACPI_DEBUG_PRINT((ACPI_DB_INFO
,
479 "Throttling state set to T%d (%d%%)\n", state
,
480 (pr
->throttling
.states
[state
].performance
? pr
->
481 throttling
.states
[state
].performance
/ 10 : 0)));
486 static int acpi_processor_set_throttling_ptc(struct acpi_processor
*pr
,
494 if ((state
< 0) || (state
> (pr
->throttling
.state_count
- 1)))
497 if (!pr
->flags
.throttling
)
500 if (state
== pr
->throttling
.state
)
503 if (state
< pr
->throttling_platform_limit
)
508 value
= acpi_get_throttling_value(pr
, state
);
510 acpi_write_throttling_state(&pr
->throttling
, value
);
511 pr
->throttling
.state
= state
;
518 int acpi_processor_set_throttling(struct acpi_processor
*pr
, int state
)
520 return pr
->throttling
.acpi_processor_set_throttling(pr
, state
);
523 int acpi_processor_get_throttling_info(struct acpi_processor
*pr
)
532 ACPI_DEBUG_PRINT((ACPI_DB_INFO
,
533 "pblk_address[0x%08x] duty_offset[%d] duty_width[%d]\n",
534 pr
->throttling
.address
,
535 pr
->throttling
.duty_offset
,
536 pr
->throttling
.duty_width
));
541 /* TBD: Support ACPI 2.0 objects */
542 no_ptc
= acpi_processor_get_throttling_control(pr
);
543 no_tss
= acpi_processor_get_throttling_states(pr
);
544 no_tsd
= acpi_processor_get_tsd(pr
);
546 if (no_ptc
|| no_tss
) {
547 pr
->throttling
.acpi_processor_get_throttling
=
548 &acpi_processor_get_throttling_fadt
;
549 pr
->throttling
.acpi_processor_set_throttling
=
550 &acpi_processor_set_throttling_fadt
;
552 pr
->throttling
.acpi_processor_get_throttling
=
553 &acpi_processor_get_throttling_ptc
;
554 pr
->throttling
.acpi_processor_set_throttling
=
555 &acpi_processor_set_throttling_ptc
;
558 if (!pr
->throttling
.address
) {
559 ACPI_DEBUG_PRINT((ACPI_DB_INFO
, "No throttling register\n"));
561 } else if (!pr
->throttling
.duty_width
) {
562 ACPI_DEBUG_PRINT((ACPI_DB_INFO
, "No throttling states\n"));
565 /* TBD: Support duty_cycle values that span bit 4. */
566 else if ((pr
->throttling
.duty_offset
+ pr
->throttling
.duty_width
) > 4) {
567 printk(KERN_WARNING PREFIX
"duty_cycle spans bit 4\n");
572 * PIIX4 Errata: We don't support throttling on the original PIIX4.
573 * This shouldn't be an issue as few (if any) mobile systems ever
576 if (errata
.piix4
.throttle
) {
577 ACPI_DEBUG_PRINT((ACPI_DB_INFO
,
578 "Throttling not supported on PIIX4 A- or B-step\n"));
582 pr
->throttling
.state_count
= 1 << acpi_gbl_FADT
.duty_width
;
585 * Compute state values. Note that throttling displays a linear power/
586 * performance relationship (at 50% performance the CPU will consume
587 * 50% power). Values are in 1/10th of a percent to preserve accuracy.
590 step
= (1000 / pr
->throttling
.state_count
);
592 for (i
= 0; i
< pr
->throttling
.state_count
; i
++) {
593 pr
->throttling
.states
[i
].performance
= step
* i
;
594 pr
->throttling
.states
[i
].power
= step
* i
;
597 ACPI_DEBUG_PRINT((ACPI_DB_INFO
, "Found %d throttling states\n",
598 pr
->throttling
.state_count
));
600 pr
->flags
.throttling
= 1;
603 * Disable throttling (if enabled). We'll let subsequent policy (e.g.
604 * thermal) decide to lower performance if it so chooses, but for now
605 * we'll crank up the speed.
608 result
= acpi_processor_get_throttling(pr
);
612 if (pr
->throttling
.state
) {
613 ACPI_DEBUG_PRINT((ACPI_DB_INFO
,
614 "Disabling throttling (was T%d)\n",
615 pr
->throttling
.state
));
616 result
= acpi_processor_set_throttling(pr
, 0);
623 pr
->flags
.throttling
= 0;
630 static int acpi_processor_throttling_seq_show(struct seq_file
*seq
,
633 struct acpi_processor
*pr
= seq
->private;
640 if (!(pr
->throttling
.state_count
> 0)) {
641 seq_puts(seq
, "<not supported>\n");
645 result
= acpi_processor_get_throttling(pr
);
649 "Could not determine current throttling state.\n");
653 seq_printf(seq
, "state count: %d\n"
654 "active state: T%d\n"
655 "state available: T%d to T%d\n",
656 pr
->throttling
.state_count
, pr
->throttling
.state
,
657 pr
->throttling_platform_limit
,
658 pr
->throttling
.state_count
- 1);
660 seq_puts(seq
, "states:\n");
661 if (pr
->throttling
.acpi_processor_get_throttling
==
662 acpi_processor_get_throttling_fadt
) {
663 for (i
= 0; i
< pr
->throttling
.state_count
; i
++)
664 seq_printf(seq
, " %cT%d: %02d%%\n",
665 (i
== pr
->throttling
.state
? '*' : ' '), i
,
666 (pr
->throttling
.states
[i
].performance
? pr
->
667 throttling
.states
[i
].performance
/ 10 : 0));
669 for (i
= 0; i
< pr
->throttling
.state_count
; i
++)
670 seq_printf(seq
, " %cT%d: %02d%%\n",
671 (i
== pr
->throttling
.state
? '*' : ' '), i
,
672 (int)pr
->throttling
.states_tss
[i
].
680 static int acpi_processor_throttling_open_fs(struct inode
*inode
,
683 return single_open(file
, acpi_processor_throttling_seq_show
,
687 static ssize_t
acpi_processor_write_throttling(struct file
*file
,
688 const char __user
* buffer
,
689 size_t count
, loff_t
* data
)
692 struct seq_file
*m
= file
->private_data
;
693 struct acpi_processor
*pr
= m
->private;
694 char state_string
[12] = { '\0' };
696 if (!pr
|| (count
> sizeof(state_string
) - 1))
699 if (copy_from_user(state_string
, buffer
, count
))
702 state_string
[count
] = '\0';
704 result
= acpi_processor_set_throttling(pr
,
705 simple_strtoul(state_string
,
713 struct file_operations acpi_processor_throttling_fops
= {
714 .open
= acpi_processor_throttling_open_fs
,
716 .write
= acpi_processor_write_throttling
,
718 .release
= single_release
,