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
"Invalid _PTC data (control_register)\n");
109 memcpy(&pr
->throttling
.control_register
, obj
.buffer
.pointer
,
110 sizeof(struct acpi_ptc_register
));
116 obj
= ptc
->package
.elements
[1];
118 if ((obj
.type
!= ACPI_TYPE_BUFFER
)
119 || (obj
.buffer
.length
< sizeof(struct acpi_ptc_register
))
120 || (obj
.buffer
.pointer
== NULL
)) {
121 printk(KERN_ERR PREFIX
"Invalid _PTC data (status_register)\n");
126 memcpy(&pr
->throttling
.status_register
, obj
.buffer
.pointer
,
127 sizeof(struct acpi_ptc_register
));
130 kfree(buffer
.pointer
);
134 static int acpi_processor_get_throttling_states(struct acpi_processor
*pr
)
137 acpi_status status
= AE_OK
;
138 struct acpi_buffer buffer
= { ACPI_ALLOCATE_BUFFER
, NULL
};
139 struct acpi_buffer format
= { sizeof("NNNNN"), "NNNNN" };
140 struct acpi_buffer state
= { 0, NULL
};
141 union acpi_object
*tss
= NULL
;
144 status
= acpi_evaluate_object(pr
->handle
, "_TSS", NULL
, &buffer
);
145 if (ACPI_FAILURE(status
)) {
146 ACPI_EXCEPTION((AE_INFO
, status
, "Evaluating _TSS"));
150 tss
= buffer
.pointer
;
151 if (!tss
|| (tss
->type
!= ACPI_TYPE_PACKAGE
)) {
152 printk(KERN_ERR PREFIX
"Invalid _TSS data\n");
157 ACPI_DEBUG_PRINT((ACPI_DB_INFO
, "Found %d throttling states\n",
158 tss
->package
.count
));
160 pr
->throttling
.state_count
= tss
->package
.count
;
161 pr
->throttling
.states_tss
=
162 kmalloc(sizeof(struct acpi_processor_tx_tss
) * tss
->package
.count
,
164 if (!pr
->throttling
.states_tss
) {
169 for (i
= 0; i
< pr
->throttling
.state_count
; i
++) {
171 struct acpi_processor_tx_tss
*tx
= (struct acpi_processor_tx_tss
*) &(pr
->throttling
.states_tss
[i
]);
173 state
.length
= sizeof(struct acpi_processor_tx_tss
);
176 ACPI_DEBUG_PRINT((ACPI_DB_INFO
, "Extracting state %d\n", i
));
178 status
= acpi_extract_package(&(tss
->package
.elements
[i
]),
180 if (ACPI_FAILURE(status
)) {
181 ACPI_EXCEPTION((AE_INFO
, status
, "Invalid _TSS data"));
183 kfree(pr
->throttling
.states_tss
);
187 if (!tx
->freqpercentage
) {
188 printk(KERN_ERR PREFIX
189 "Invalid _TSS data: freq is zero\n");
191 kfree(pr
->throttling
.states_tss
);
197 kfree(buffer
.pointer
);
201 static int acpi_processor_get_tsd(struct acpi_processor
*pr
)
204 acpi_status status
= AE_OK
;
205 struct acpi_buffer buffer
= {ACPI_ALLOCATE_BUFFER
, NULL
};
206 struct acpi_buffer format
= {sizeof("NNNNN"), "NNNNN"};
207 struct acpi_buffer state
= {0, NULL
};
208 union acpi_object
*tsd
= NULL
;
209 struct acpi_tsd_package
*pdomain
;
211 status
= acpi_evaluate_object(pr
->handle
, "_TSD", NULL
, &buffer
);
212 if (ACPI_FAILURE(status
)) {
216 tsd
= buffer
.pointer
;
217 if (!tsd
|| (tsd
->type
!= ACPI_TYPE_PACKAGE
)) {
218 ACPI_DEBUG_PRINT((ACPI_DB_ERROR
, "Invalid _TSD data\n"));
223 if (tsd
->package
.count
!= 1) {
224 ACPI_DEBUG_PRINT((ACPI_DB_ERROR
, "Invalid _TSD data\n"));
229 pdomain
= &(pr
->throttling
.domain_info
);
231 state
.length
= sizeof(struct acpi_tsd_package
);
232 state
.pointer
= pdomain
;
234 status
= acpi_extract_package(&(tsd
->package
.elements
[0]),
236 if (ACPI_FAILURE(status
)) {
237 ACPI_DEBUG_PRINT((ACPI_DB_ERROR
, "Invalid _TSD data\n"));
242 if (pdomain
->num_entries
!= ACPI_TSD_REV0_ENTRIES
) {
243 ACPI_DEBUG_PRINT((ACPI_DB_ERROR
, "Unknown _TSD:num_entries\n"));
248 if (pdomain
->revision
!= ACPI_TSD_REV0_REVISION
) {
249 ACPI_DEBUG_PRINT((ACPI_DB_ERROR
, "Unknown _TSD:revision\n"));
255 kfree(buffer
.pointer
);
259 /* --------------------------------------------------------------------------
261 -------------------------------------------------------------------------- */
262 static int acpi_processor_get_throttling_fadt(struct acpi_processor
*pr
)
273 if (!pr
->flags
.throttling
)
276 pr
->throttling
.state
= 0;
278 duty_mask
= pr
->throttling
.state_count
- 1;
280 duty_mask
<<= pr
->throttling
.duty_offset
;
284 value
= inl(pr
->throttling
.address
);
287 * Compute the current throttling state when throttling is enabled
291 duty_value
= value
& duty_mask
;
292 duty_value
>>= pr
->throttling
.duty_offset
;
295 state
= pr
->throttling
.state_count
- duty_value
;
298 pr
->throttling
.state
= state
;
302 ACPI_DEBUG_PRINT((ACPI_DB_INFO
,
303 "Throttling state is T%d (%d%% throttling applied)\n",
304 state
, pr
->throttling
.states
[state
].performance
));
309 static int acpi_read_throttling_status(struct acpi_processor_throttling
*throttling
)
312 switch (throttling
->status_register
.space_id
) {
313 case ACPI_ADR_SPACE_SYSTEM_IO
:
314 acpi_os_read_port((acpi_io_address
)throttling
->status_register
.address
,
316 (u32
)throttling
->status_register
.bit_width
*8);
318 case ACPI_ADR_SPACE_FIXED_HARDWARE
:
319 printk(KERN_ERR PREFIX
"HARDWARE addr space,NOT supported yet\n");
322 printk(KERN_ERR PREFIX
"Unknown addr space %d\n",
323 (u32
) (throttling
->status_register
.space_id
));
328 static int acpi_write_throttling_state(struct acpi_processor_throttling
*throttling
,int value
)
332 switch (throttling
->control_register
.space_id
) {
333 case ACPI_ADR_SPACE_SYSTEM_IO
:
334 acpi_os_write_port((acpi_io_address
)throttling
->control_register
.address
,
336 (u32
)throttling
->control_register
.bit_width
*8);
339 case ACPI_ADR_SPACE_FIXED_HARDWARE
:
340 printk(KERN_ERR PREFIX
"HARDWARE addr space,NOT supported yet\n");
343 printk(KERN_ERR PREFIX
"Unknown addr space %d\n",
344 (u32
) (throttling
->control_register
.space_id
));
349 static int acpi_get_throttling_state(struct acpi_processor
*pr
,int value
)
353 for (i
= 0; i
< pr
->throttling
.state_count
; i
++) {
354 struct acpi_processor_tx_tss
*tx
= (struct acpi_processor_tx_tss
*) &(pr
->throttling
.states_tss
[i
]);
355 if(tx
->control
== value
)
358 if(i
> pr
->throttling
.state_count
)
363 static int acpi_get_throttling_value(struct acpi_processor
*pr
,int state
)
366 if(state
>=0 && state
<= pr
->throttling
.state_count
){
367 struct acpi_processor_tx_tss
*tx
= (struct acpi_processor_tx_tss
*) &(pr
->throttling
.states_tss
[state
]);
373 static int acpi_processor_get_throttling_ptc(struct acpi_processor
*pr
)
382 if (!pr
->flags
.throttling
)
385 pr
->throttling
.state
= 0;
387 value
= acpi_read_throttling_status(&pr
->throttling
);
389 state
= acpi_get_throttling_state(pr
,value
);
390 pr
->throttling
.state
= state
;
398 static int acpi_processor_get_throttling(struct acpi_processor
*pr
)
400 return pr
->throttling
.acpi_processor_get_throttling(pr
);
403 int acpi_processor_set_throttling_fadt(struct acpi_processor
*pr
, int state
)
413 if ((state
< 0) || (state
> (pr
->throttling
.state_count
- 1)))
416 if (!pr
->flags
.throttling
)
419 if (state
== pr
->throttling
.state
)
422 if (state
< pr
->throttling_platform_limit
)
425 * Calculate the duty_value and duty_mask.
428 duty_value
= pr
->throttling
.state_count
- state
;
430 duty_value
<<= pr
->throttling
.duty_offset
;
432 /* Used to clear all duty_value bits */
433 duty_mask
= pr
->throttling
.state_count
- 1;
435 duty_mask
<<= acpi_gbl_FADT
.duty_offset
;
436 duty_mask
= ~duty_mask
;
442 * Disable throttling by writing a 0 to bit 4. Note that we must
443 * turn it off before you can change the duty_value.
445 value
= inl(pr
->throttling
.address
);
448 outl(value
, pr
->throttling
.address
);
452 * Write the new duty_value and then enable throttling. Note
453 * that a state value of 0 leaves throttling disabled.
458 outl(value
, pr
->throttling
.address
);
461 outl(value
, pr
->throttling
.address
);
464 pr
->throttling
.state
= state
;
468 ACPI_DEBUG_PRINT((ACPI_DB_INFO
,
469 "Throttling state set to T%d (%d%%)\n", state
,
470 (pr
->throttling
.states
[state
].performance
? pr
->
471 throttling
.states
[state
].performance
/ 10 : 0)));
476 int acpi_processor_set_throttling_ptc(struct acpi_processor
*pr
, int state
)
483 if ((state
< 0) || (state
> (pr
->throttling
.state_count
- 1)))
486 if (!pr
->flags
.throttling
)
489 if (state
== pr
->throttling
.state
)
492 if (state
< pr
->throttling_platform_limit
)
497 value
= acpi_get_throttling_value(pr
,state
);
499 acpi_write_throttling_state(&pr
->throttling
,value
);
500 pr
->throttling
.state
= state
;
507 int acpi_processor_set_throttling(struct acpi_processor
*pr
, int state
)
509 return pr
->throttling
.acpi_processor_set_throttling(pr
,state
);
512 int acpi_processor_get_throttling_info(struct acpi_processor
*pr
)
522 ACPI_DEBUG_PRINT((ACPI_DB_INFO
,
523 "pblk_address[0x%08x] duty_offset[%d] duty_width[%d]\n",
524 pr
->throttling
.address
,
525 pr
->throttling
.duty_offset
,
526 pr
->throttling
.duty_width
));
531 /* TBD: Support ACPI 2.0 objects */
532 no_ptc
= acpi_processor_get_throttling_control(pr
);
533 no_tss
= acpi_processor_get_throttling_states(pr
);
534 no_tsd
= acpi_processor_get_tsd(pr
);
536 if(no_ptc
|| no_tss
) {
537 pr
->throttling
.acpi_processor_get_throttling
= &acpi_processor_get_throttling_fadt
;
538 pr
->throttling
.acpi_processor_set_throttling
= &acpi_processor_set_throttling_fadt
;
540 pr
->throttling
.acpi_processor_get_throttling
= &acpi_processor_get_throttling_ptc
;
541 pr
->throttling
.acpi_processor_set_throttling
= &acpi_processor_set_throttling_ptc
;
544 if (!pr
->throttling
.address
) {
545 ACPI_DEBUG_PRINT((ACPI_DB_INFO
, "No throttling register\n"));
547 } else if (!pr
->throttling
.duty_width
) {
548 ACPI_DEBUG_PRINT((ACPI_DB_INFO
, "No throttling states\n"));
551 /* TBD: Support duty_cycle values that span bit 4. */
552 else if ((pr
->throttling
.duty_offset
+ pr
->throttling
.duty_width
) > 4) {
553 printk(KERN_WARNING PREFIX
"duty_cycle spans bit 4\n");
558 * PIIX4 Errata: We don't support throttling on the original PIIX4.
559 * This shouldn't be an issue as few (if any) mobile systems ever
562 if (errata
.piix4
.throttle
) {
563 ACPI_DEBUG_PRINT((ACPI_DB_INFO
,
564 "Throttling not supported on PIIX4 A- or B-step\n"));
568 pr
->throttling
.state_count
= 1 << acpi_gbl_FADT
.duty_width
;
571 * Compute state values. Note that throttling displays a linear power/
572 * performance relationship (at 50% performance the CPU will consume
573 * 50% power). Values are in 1/10th of a percent to preserve accuracy.
576 step
= (1000 / pr
->throttling
.state_count
);
578 for (i
= 0; i
< pr
->throttling
.state_count
; i
++) {
579 pr
->throttling
.states
[i
].performance
= step
* i
;
580 pr
->throttling
.states
[i
].power
= step
* i
;
583 ACPI_DEBUG_PRINT((ACPI_DB_INFO
, "Found %d throttling states\n",
584 pr
->throttling
.state_count
));
586 pr
->flags
.throttling
= 1;
589 * Disable throttling (if enabled). We'll let subsequent policy (e.g.
590 * thermal) decide to lower performance if it so chooses, but for now
591 * we'll crank up the speed.
594 result
= acpi_processor_get_throttling(pr
);
598 if (pr
->throttling
.state
) {
599 ACPI_DEBUG_PRINT((ACPI_DB_INFO
,
600 "Disabling throttling (was T%d)\n",
601 pr
->throttling
.state
));
602 result
= acpi_processor_set_throttling(pr
, 0);
609 pr
->flags
.throttling
= 0;
616 static int acpi_processor_throttling_seq_show(struct seq_file
*seq
,
619 struct acpi_processor
*pr
= seq
->private;
627 if (!(pr
->throttling
.state_count
> 0)) {
628 seq_puts(seq
, "<not supported>\n");
632 result
= acpi_processor_get_throttling(pr
);
636 "Could not determine current throttling state.\n");
640 seq_printf(seq
, "state count: %d\n"
641 "active state: T%d\n"
642 "state available: T%d to T%d\n",
643 pr
->throttling
.state_count
, pr
->throttling
.state
,
644 pr
->throttling_platform_limit
,
645 pr
->throttling
.state_count
-1);
647 seq_puts(seq
, "states:\n");
648 if(acpi_processor_get_throttling
== acpi_processor_get_throttling_fadt
)
649 for (i
= 0; i
< pr
->throttling
.state_count
; i
++)
650 seq_printf(seq
, " %cT%d: %02d%%\n",
651 (i
== pr
->throttling
.state
? '*' : ' '), i
,
652 (pr
->throttling
.states
[i
].performance
? pr
->
653 throttling
.states
[i
].performance
/ 10 : 0));
655 for (i
= 0; i
< pr
->throttling
.state_count
; i
++)
656 seq_printf(seq
, " %cT%d: %02d%%\n",
657 (i
== pr
->throttling
.state
? '*' : ' '), i
,
658 (int)pr
->throttling
.states_tss
[i
].freqpercentage
);
665 static int acpi_processor_throttling_open_fs(struct inode
*inode
,
668 return single_open(file
, acpi_processor_throttling_seq_show
,
672 static ssize_t
acpi_processor_write_throttling(struct file
* file
,
673 const char __user
* buffer
,
674 size_t count
, loff_t
* data
)
677 struct seq_file
*m
= file
->private_data
;
678 struct acpi_processor
*pr
= m
->private;
679 char state_string
[12] = { '\0' };
682 if (!pr
|| (count
> sizeof(state_string
) - 1))
685 if (copy_from_user(state_string
, buffer
, count
))
688 state_string
[count
] = '\0';
690 result
= acpi_processor_set_throttling(pr
,
691 simple_strtoul(state_string
,
699 struct file_operations acpi_processor_throttling_fops
= {
700 .open
= acpi_processor_throttling_open_fs
,
702 .write
= acpi_processor_write_throttling
,
704 .release
= single_release
,