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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * (C) 2001 Dave Jones, Arjan van de ven.
3 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
4 *
5 * Licensed under the terms of the GNU GPL License version 2.
6 * Based upon reverse engineered information, and on Intel documentation
7 * for chipsets ICH2-M and ICH3-M.
8 *
9 * Many thanks to Ducrot Bruno for finding and fixing the last
10 * "missing link" for ICH2-M/ICH3-M support, and to Thomas Winkler
11 * for extensive testing.
12 *
13 * BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
14 */
15
16
17/*********************************************************************
18 * SPEEDSTEP - DEFINITIONS *
19 *********************************************************************/
20
21#include <linux/kernel.h>
22#include <linux/module.h>
23#include <linux/init.h>
24#include <linux/cpufreq.h>
25#include <linux/pci.h>
Alexey Dobriyane8edc6e2007-05-21 01:22:52 +040026#include <linux/sched.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027
28#include "speedstep-lib.h"
29
30
31/* speedstep_chipset:
32 * It is necessary to know which chipset is used. As accesses to
33 * this device occur at various places in this module, we need a
34 * static struct pci_dev * pointing to that device.
35 */
36static struct pci_dev *speedstep_chipset_dev;
37
38
39/* speedstep_processor
40 */
Rusty Russell1cce76c2009-11-17 14:39:53 -080041static enum speedstep_processor speedstep_processor;
Linus Torvalds1da177e2005-04-16 15:20:36 -070042
Mattia Dongili9a7d82a2005-11-30 22:00:59 +010043static u32 pmbase;
Linus Torvalds1da177e2005-04-16 15:20:36 -070044
45/*
46 * There are only two frequency states for each processor. Values
47 * are in kHz for the time being.
48 */
49static struct cpufreq_frequency_table speedstep_freqs[] = {
50 {SPEEDSTEP_HIGH, 0},
51 {SPEEDSTEP_LOW, 0},
52 {0, CPUFREQ_TABLE_END},
53};
54
55
Linus Torvalds1da177e2005-04-16 15:20:36 -070056/**
Mattia Dongili9a7d82a2005-11-30 22:00:59 +010057 * speedstep_find_register - read the PMBASE address
58 *
59 * Returns: -ENODEV if no register could be found
60 */
Dave Jonesbbfebd62009-01-17 23:55:22 -050061static int speedstep_find_register(void)
Mattia Dongili9a7d82a2005-11-30 22:00:59 +010062{
63 if (!speedstep_chipset_dev)
64 return -ENODEV;
65
66 /* get PMBASE */
67 pci_read_config_dword(speedstep_chipset_dev, 0x40, &pmbase);
68 if (!(pmbase & 0x01)) {
69 printk(KERN_ERR "speedstep-ich: could not find speedstep register\n");
70 return -ENODEV;
71 }
72
73 pmbase &= 0xFFFFFFFE;
74 if (!pmbase) {
75 printk(KERN_ERR "speedstep-ich: could not find speedstep register\n");
76 return -ENODEV;
77 }
78
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +020079 pr_debug("pmbase is 0x%x\n", pmbase);
Mattia Dongili9a7d82a2005-11-30 22:00:59 +010080 return 0;
81}
82
83/**
Linus Torvalds1da177e2005-04-16 15:20:36 -070084 * speedstep_set_state - set the SpeedStep state
85 * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
86 *
Rusty Russell394122a2009-06-11 22:59:58 +093087 * Tries to change the SpeedStep state. Can be called from
88 * smp_call_function_single.
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 */
Dave Jonesbbfebd62009-01-17 23:55:22 -050090static void speedstep_set_state(unsigned int state)
Linus Torvalds1da177e2005-04-16 15:20:36 -070091{
Linus Torvalds1da177e2005-04-16 15:20:36 -070092 u8 pm2_blk;
93 u8 value;
94 unsigned long flags;
95
Mattia Dongili9a7d82a2005-11-30 22:00:59 +010096 if (state > 0x1)
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 return;
98
Linus Torvalds1da177e2005-04-16 15:20:36 -070099 /* Disable IRQs */
100 local_irq_save(flags);
101
102 /* read state */
103 value = inb(pmbase + 0x50);
104
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200105 pr_debug("read at pmbase 0x%x + 0x50 returned 0x%x\n", pmbase, value);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106
107 /* write new state */
108 value &= 0xFE;
109 value |= state;
110
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200111 pr_debug("writing 0x%x to pmbase 0x%x + 0x50\n", value, pmbase);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112
113 /* Disable bus master arbitration */
114 pm2_blk = inb(pmbase + 0x20);
115 pm2_blk |= 0x01;
116 outb(pm2_blk, (pmbase + 0x20));
117
118 /* Actual transition */
119 outb(value, (pmbase + 0x50));
120
121 /* Restore bus master arbitration */
122 pm2_blk &= 0xfe;
123 outb(pm2_blk, (pmbase + 0x20));
124
125 /* check if transition was successful */
126 value = inb(pmbase + 0x50);
127
128 /* Enable IRQs */
129 local_irq_restore(flags);
130
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200131 pr_debug("read at pmbase 0x%x + 0x50 returned 0x%x\n", pmbase, value);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132
Dave Jonesbbfebd62009-01-17 23:55:22 -0500133 if (state == (value & 0x1))
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200134 pr_debug("change to %u MHz succeeded\n",
Dave Jonesbbfebd62009-01-17 23:55:22 -0500135 speedstep_get_frequency(speedstep_processor) / 1000);
136 else
137 printk(KERN_ERR "cpufreq: change failed - I/O error\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138
139 return;
140}
141
Rusty Russell394122a2009-06-11 22:59:58 +0930142/* Wrapper for smp_call_function_single. */
143static void _speedstep_set_state(void *_state)
144{
145 speedstep_set_state(*(unsigned int *)_state);
146}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147
148/**
149 * speedstep_activate - activate SpeedStep control in the chipset
150 *
151 * Tries to activate the SpeedStep status and control registers.
152 * Returns -EINVAL on an unsupported chipset, and zero on success.
153 */
Dave Jonesbbfebd62009-01-17 23:55:22 -0500154static int speedstep_activate(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155{
156 u16 value = 0;
157
158 if (!speedstep_chipset_dev)
159 return -EINVAL;
160
161 pci_read_config_word(speedstep_chipset_dev, 0x00A0, &value);
162 if (!(value & 0x08)) {
163 value |= 0x08;
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200164 pr_debug("activating SpeedStep (TM) registers\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 pci_write_config_word(speedstep_chipset_dev, 0x00A0, value);
166 }
167
168 return 0;
169}
170
171
172/**
173 * speedstep_detect_chipset - detect the Southbridge which contains SpeedStep logic
174 *
175 * Detects ICH2-M, ICH3-M and ICH4-M so far. The pci_dev points to
176 * the LPC bridge / PM module which contains all power-management
177 * functions. Returns the SPEEDSTEP_CHIPSET_-number for the detected
178 * chipset, or zero on failure.
179 */
Dave Jonesbbfebd62009-01-17 23:55:22 -0500180static unsigned int speedstep_detect_chipset(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181{
182 speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
183 PCI_DEVICE_ID_INTEL_82801DB_12,
Dave Jonesbbfebd62009-01-17 23:55:22 -0500184 PCI_ANY_ID, PCI_ANY_ID,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 NULL);
186 if (speedstep_chipset_dev)
187 return 4; /* 4-M */
188
189 speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
190 PCI_DEVICE_ID_INTEL_82801CA_12,
Dave Jonesbbfebd62009-01-17 23:55:22 -0500191 PCI_ANY_ID, PCI_ANY_ID,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192 NULL);
193 if (speedstep_chipset_dev)
194 return 3; /* 3-M */
195
196
197 speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
198 PCI_DEVICE_ID_INTEL_82801BA_10,
Dave Jonesbbfebd62009-01-17 23:55:22 -0500199 PCI_ANY_ID, PCI_ANY_ID,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 NULL);
201 if (speedstep_chipset_dev) {
202 /* speedstep.c causes lockups on Dell Inspirons 8000 and
203 * 8100 which use a pretty old revision of the 82815
204 * host brige. Abort on these systems.
205 */
206 static struct pci_dev *hostbridge;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207
208 hostbridge = pci_get_subsys(PCI_VENDOR_ID_INTEL,
209 PCI_DEVICE_ID_INTEL_82815_MC,
Dave Jonesbbfebd62009-01-17 23:55:22 -0500210 PCI_ANY_ID, PCI_ANY_ID,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 NULL);
212
213 if (!hostbridge)
214 return 2; /* 2-M */
215
Auke Kok44c10132007-06-08 15:46:36 -0700216 if (hostbridge->revision < 5) {
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200217 pr_debug("hostbridge does not support speedstep\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 speedstep_chipset_dev = NULL;
219 pci_dev_put(hostbridge);
220 return 0;
221 }
222
223 pci_dev_put(hostbridge);
224 return 2; /* 2-M */
225 }
226
227 return 0;
228}
229
Rusty Russell8dca15e2009-11-02 23:35:30 -0800230static void get_freq_data(void *_speed)
Rusty Russell394122a2009-06-11 22:59:58 +0930231{
Rusty Russell8dca15e2009-11-02 23:35:30 -0800232 unsigned int *speed = _speed;
Rusty Russell394122a2009-06-11 22:59:58 +0930233
Rusty Russell8dca15e2009-11-02 23:35:30 -0800234 *speed = speedstep_get_frequency(speedstep_processor);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235}
236
237static unsigned int speedstep_get(unsigned int cpu)
238{
Rusty Russell8dca15e2009-11-02 23:35:30 -0800239 unsigned int speed;
Rusty Russell394122a2009-06-11 22:59:58 +0930240
241 /* You're supposed to ensure CPU is online. */
Rusty Russell8dca15e2009-11-02 23:35:30 -0800242 if (smp_call_function_single(cpu, get_freq_data, &speed, 1) != 0)
Rusty Russell394122a2009-06-11 22:59:58 +0930243 BUG();
244
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200245 pr_debug("detected %u kHz as current frequency\n", speed);
Rusty Russell8dca15e2009-11-02 23:35:30 -0800246 return speed;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247}
248
249/**
250 * speedstep_target - set a new CPUFreq policy
251 * @policy: new policy
252 * @target_freq: the target frequency
Dave Jonesbbfebd62009-01-17 23:55:22 -0500253 * @relation: how that frequency relates to achieved frequency
254 * (CPUFREQ_RELATION_L or CPUFREQ_RELATION_H)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255 *
256 * Sets a new CPUFreq policy.
257 */
Dave Jonesbbfebd62009-01-17 23:55:22 -0500258static int speedstep_target(struct cpufreq_policy *policy,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 unsigned int target_freq,
260 unsigned int relation)
261{
Rusty Russell394122a2009-06-11 22:59:58 +0930262 unsigned int newstate = 0, policy_cpu;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263 struct cpufreq_freqs freqs;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264 int i;
265
Dave Jonesbbfebd62009-01-17 23:55:22 -0500266 if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0],
267 target_freq, relation, &newstate))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 return -EINVAL;
269
Rusty Russell394122a2009-06-11 22:59:58 +0930270 policy_cpu = cpumask_any_and(policy->cpus, cpu_online_mask);
271 freqs.old = speedstep_get(policy_cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272 freqs.new = speedstep_freqs[newstate].frequency;
273 freqs.cpu = policy->cpu;
274
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200275 pr_debug("transiting from %u to %u kHz\n", freqs.old, freqs.new);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276
277 /* no transition necessary */
278 if (freqs.old == freqs.new)
279 return 0;
280
Rusty Russell835481d2009-01-04 05:18:06 -0800281 for_each_cpu(i, policy->cpus) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282 freqs.cpu = i;
283 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
284 }
285
Rusty Russell394122a2009-06-11 22:59:58 +0930286 smp_call_function_single(policy_cpu, _speedstep_set_state, &newstate,
287 true);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288
Rusty Russell835481d2009-01-04 05:18:06 -0800289 for_each_cpu(i, policy->cpus) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 freqs.cpu = i;
291 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
292 }
293
294 return 0;
295}
296
297
298/**
299 * speedstep_verify - verifies a new CPUFreq policy
300 * @policy: new policy
301 *
302 * Limit must be within speedstep_low_freq and speedstep_high_freq, with
303 * at least one border included.
304 */
Dave Jonesbbfebd62009-01-17 23:55:22 -0500305static int speedstep_verify(struct cpufreq_policy *policy)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306{
307 return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
308}
309
Rusty Russell394122a2009-06-11 22:59:58 +0930310struct get_freqs {
311 struct cpufreq_policy *policy;
312 int ret;
313};
314
315static void get_freqs_on_cpu(void *_get_freqs)
316{
317 struct get_freqs *get_freqs = _get_freqs;
318
319 get_freqs->ret =
320 speedstep_get_freqs(speedstep_processor,
321 &speedstep_freqs[SPEEDSTEP_LOW].frequency,
322 &speedstep_freqs[SPEEDSTEP_HIGH].frequency,
323 &get_freqs->policy->cpuinfo.transition_latency,
324 &speedstep_set_state);
325}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326
327static int speedstep_cpu_init(struct cpufreq_policy *policy)
328{
Rusty Russell394122a2009-06-11 22:59:58 +0930329 int result;
330 unsigned int policy_cpu, speed;
331 struct get_freqs gf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332
333 /* only run on CPU to be set, or on its sibling */
334#ifdef CONFIG_SMP
Rusty Russell7ad728f2009-03-13 14:49:50 +1030335 cpumask_copy(policy->cpus, cpu_sibling_mask(policy->cpu));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336#endif
Rusty Russell394122a2009-06-11 22:59:58 +0930337 policy_cpu = cpumask_any_and(policy->cpus, cpu_online_mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338
Mattia Dongili1a107602005-12-02 21:59:41 +0100339 /* detect low and high frequency and transition latency */
Rusty Russell394122a2009-06-11 22:59:58 +0930340 gf.policy = policy;
341 smp_call_function_single(policy_cpu, get_freqs_on_cpu, &gf, 1);
342 if (gf.ret)
343 return gf.ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344
345 /* get current speed setting */
Rusty Russell394122a2009-06-11 22:59:58 +0930346 speed = speedstep_get(policy_cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 if (!speed)
348 return -EIO;
349
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200350 pr_debug("currently at %s speed setting - %i MHz\n",
Dave Jonesbbfebd62009-01-17 23:55:22 -0500351 (speed == speedstep_freqs[SPEEDSTEP_LOW].frequency)
352 ? "low" : "high",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 (speed / 1000));
354
355 /* cpuinfo and default policy values */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356 policy->cur = speed;
357
358 result = cpufreq_frequency_table_cpuinfo(policy, speedstep_freqs);
359 if (result)
Dave Jonesbbfebd62009-01-17 23:55:22 -0500360 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361
Dave Jonesbbfebd62009-01-17 23:55:22 -0500362 cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363
364 return 0;
365}
366
367
368static int speedstep_cpu_exit(struct cpufreq_policy *policy)
369{
370 cpufreq_frequency_table_put_attr(policy->cpu);
371 return 0;
372}
373
Dave Jonesbbfebd62009-01-17 23:55:22 -0500374static struct freq_attr *speedstep_attr[] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375 &cpufreq_freq_attr_scaling_available_freqs,
376 NULL,
377};
378
379
Linus Torvalds221dee22007-02-26 14:55:48 -0800380static struct cpufreq_driver speedstep_driver = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381 .name = "speedstep-ich",
382 .verify = speedstep_verify,
383 .target = speedstep_target,
384 .init = speedstep_cpu_init,
385 .exit = speedstep_cpu_exit,
386 .get = speedstep_get,
387 .owner = THIS_MODULE,
388 .attr = speedstep_attr,
389};
390
391
392/**
393 * speedstep_init - initializes the SpeedStep CPUFreq driver
394 *
395 * Initializes the SpeedStep support. Returns -ENODEV on unsupported
396 * devices, -EINVAL on problems during initiatization, and zero on
397 * success.
398 */
399static int __init speedstep_init(void)
400{
401 /* detect processor */
402 speedstep_processor = speedstep_detect_processor();
403 if (!speedstep_processor) {
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200404 pr_debug("Intel(R) SpeedStep(TM) capable processor "
Dave Jonesbbfebd62009-01-17 23:55:22 -0500405 "not found\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 return -ENODEV;
407 }
408
409 /* detect chipset */
410 if (!speedstep_detect_chipset()) {
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200411 pr_debug("Intel(R) SpeedStep(TM) for this chipset not "
Dave Jonesbbfebd62009-01-17 23:55:22 -0500412 "(yet) available.\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 return -ENODEV;
414 }
415
416 /* activate speedstep support */
417 if (speedstep_activate()) {
418 pci_dev_put(speedstep_chipset_dev);
419 return -EINVAL;
420 }
421
Mattia Dongili9a7d82a2005-11-30 22:00:59 +0100422 if (speedstep_find_register())
423 return -ENODEV;
424
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425 return cpufreq_register_driver(&speedstep_driver);
426}
427
428
429/**
430 * speedstep_exit - unregisters SpeedStep support
431 *
432 * Unregisters SpeedStep support.
433 */
434static void __exit speedstep_exit(void)
435{
436 pci_dev_put(speedstep_chipset_dev);
437 cpufreq_unregister_driver(&speedstep_driver);
438}
439
440
Dave Jonesbbfebd62009-01-17 23:55:22 -0500441MODULE_AUTHOR("Dave Jones <davej@redhat.com>, "
442 "Dominik Brodowski <linux@brodo.de>");
443MODULE_DESCRIPTION("Speedstep driver for Intel mobile processors on chipsets "
444 "with ICH-M southbridges.");
445MODULE_LICENSE("GPL");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446
447module_init(speedstep_init);
448module_exit(speedstep_exit);