1 /*
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>
26 #include <linux/sched.h>
27
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 */
36 static struct pci_dev *speedstep_chipset_dev;
37
38
39 /* speedstep_processor
40 */
41 static enum speedstep_processor speedstep_processor;
42
43 static u32 pmbase;
44
45 /*
46 * There are only two frequency states for each processor. Values
47 * are in kHz for the time being.
48 */
49 static struct cpufreq_frequency_table speedstep_freqs[] = {
50 {SPEEDSTEP_HIGH, 0},
51 {SPEEDSTEP_LOW, 0},
52 {0, CPUFREQ_TABLE_END},
53 };
54
55
56 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, \
57 "speedstep-ich", msg)
58
59
60 /**
61 * speedstep_find_register - read the PMBASE address
62 *
63 * Returns: -ENODEV if no register could be found
64 */
speedstep_find_register(void)65 static int speedstep_find_register(void)
66 {
67 if (!speedstep_chipset_dev)
68 return -ENODEV;
69
70 /* get PMBASE */
71 pci_read_config_dword(speedstep_chipset_dev, 0x40, &pmbase);
72 if (!(pmbase & 0x01)) {
73 printk(KERN_ERR "speedstep-ich: could not find speedstep register\n");
74 return -ENODEV;
75 }
76
77 pmbase &= 0xFFFFFFFE;
78 if (!pmbase) {
79 printk(KERN_ERR "speedstep-ich: could not find speedstep register\n");
80 return -ENODEV;
81 }
82
83 dprintk("pmbase is 0x%x\n", pmbase);
84 return 0;
85 }
86
87 /**
88 * speedstep_set_state - set the SpeedStep state
89 * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
90 *
91 * Tries to change the SpeedStep state. Can be called from
92 * smp_call_function_single.
93 */
speedstep_set_state(unsigned int state)94 static void speedstep_set_state(unsigned int state)
95 {
96 u8 pm2_blk;
97 u8 value;
98 unsigned long flags;
99
100 if (state > 0x1)
101 return;
102
103 /* Disable IRQs */
104 local_irq_save(flags);
105
106 /* read state */
107 value = inb(pmbase + 0x50);
108
109 dprintk("read at pmbase 0x%x + 0x50 returned 0x%x\n", pmbase, value);
110
111 /* write new state */
112 value &= 0xFE;
113 value |= state;
114
115 dprintk("writing 0x%x to pmbase 0x%x + 0x50\n", value, pmbase);
116
117 /* Disable bus master arbitration */
118 pm2_blk = inb(pmbase + 0x20);
119 pm2_blk |= 0x01;
120 outb(pm2_blk, (pmbase + 0x20));
121
122 /* Actual transition */
123 outb(value, (pmbase + 0x50));
124
125 /* Restore bus master arbitration */
126 pm2_blk &= 0xfe;
127 outb(pm2_blk, (pmbase + 0x20));
128
129 /* check if transition was successful */
130 value = inb(pmbase + 0x50);
131
132 /* Enable IRQs */
133 local_irq_restore(flags);
134
135 dprintk("read at pmbase 0x%x + 0x50 returned 0x%x\n", pmbase, value);
136
137 if (state == (value & 0x1))
138 dprintk("change to %u MHz succeeded\n",
139 speedstep_get_frequency(speedstep_processor) / 1000);
140 else
141 printk(KERN_ERR "cpufreq: change failed - I/O error\n");
142
143 return;
144 }
145
146 /* Wrapper for smp_call_function_single. */
_speedstep_set_state(void * _state)147 static void _speedstep_set_state(void *_state)
148 {
149 speedstep_set_state(*(unsigned int *)_state);
150 }
151
152 /**
153 * speedstep_activate - activate SpeedStep control in the chipset
154 *
155 * Tries to activate the SpeedStep status and control registers.
156 * Returns -EINVAL on an unsupported chipset, and zero on success.
157 */
speedstep_activate(void)158 static int speedstep_activate(void)
159 {
160 u16 value = 0;
161
162 if (!speedstep_chipset_dev)
163 return -EINVAL;
164
165 pci_read_config_word(speedstep_chipset_dev, 0x00A0, &value);
166 if (!(value & 0x08)) {
167 value |= 0x08;
168 dprintk("activating SpeedStep (TM) registers\n");
169 pci_write_config_word(speedstep_chipset_dev, 0x00A0, value);
170 }
171
172 return 0;
173 }
174
175
176 /**
177 * speedstep_detect_chipset - detect the Southbridge which contains SpeedStep logic
178 *
179 * Detects ICH2-M, ICH3-M and ICH4-M so far. The pci_dev points to
180 * the LPC bridge / PM module which contains all power-management
181 * functions. Returns the SPEEDSTEP_CHIPSET_-number for the detected
182 * chipset, or zero on failure.
183 */
speedstep_detect_chipset(void)184 static unsigned int speedstep_detect_chipset(void)
185 {
186 speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
187 PCI_DEVICE_ID_INTEL_82801DB_12,
188 PCI_ANY_ID, PCI_ANY_ID,
189 NULL);
190 if (speedstep_chipset_dev)
191 return 4; /* 4-M */
192
193 speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
194 PCI_DEVICE_ID_INTEL_82801CA_12,
195 PCI_ANY_ID, PCI_ANY_ID,
196 NULL);
197 if (speedstep_chipset_dev)
198 return 3; /* 3-M */
199
200
201 speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
202 PCI_DEVICE_ID_INTEL_82801BA_10,
203 PCI_ANY_ID, PCI_ANY_ID,
204 NULL);
205 if (speedstep_chipset_dev) {
206 /* speedstep.c causes lockups on Dell Inspirons 8000 and
207 * 8100 which use a pretty old revision of the 82815
208 * host brige. Abort on these systems.
209 */
210 static struct pci_dev *hostbridge;
211
212 hostbridge = pci_get_subsys(PCI_VENDOR_ID_INTEL,
213 PCI_DEVICE_ID_INTEL_82815_MC,
214 PCI_ANY_ID, PCI_ANY_ID,
215 NULL);
216
217 if (!hostbridge)
218 return 2; /* 2-M */
219
220 if (hostbridge->revision < 5) {
221 dprintk("hostbridge does not support speedstep\n");
222 speedstep_chipset_dev = NULL;
223 pci_dev_put(hostbridge);
224 return 0;
225 }
226
227 pci_dev_put(hostbridge);
228 return 2; /* 2-M */
229 }
230
231 return 0;
232 }
233
get_freq_data(void * _speed)234 static void get_freq_data(void *_speed)
235 {
236 unsigned int *speed = _speed;
237
238 *speed = speedstep_get_frequency(speedstep_processor);
239 }
240
speedstep_get(unsigned int cpu)241 static unsigned int speedstep_get(unsigned int cpu)
242 {
243 unsigned int speed;
244
245 /* You're supposed to ensure CPU is online. */
246 if (smp_call_function_single(cpu, get_freq_data, &speed, 1) != 0)
247 BUG();
248
249 dprintk("detected %u kHz as current frequency\n", speed);
250 return speed;
251 }
252
253 /**
254 * speedstep_target - set a new CPUFreq policy
255 * @policy: new policy
256 * @target_freq: the target frequency
257 * @relation: how that frequency relates to achieved frequency
258 * (CPUFREQ_RELATION_L or CPUFREQ_RELATION_H)
259 *
260 * Sets a new CPUFreq policy.
261 */
speedstep_target(struct cpufreq_policy * policy,unsigned int target_freq,unsigned int relation)262 static int speedstep_target(struct cpufreq_policy *policy,
263 unsigned int target_freq,
264 unsigned int relation)
265 {
266 unsigned int newstate = 0, policy_cpu;
267 struct cpufreq_freqs freqs;
268 int i;
269
270 if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0],
271 target_freq, relation, &newstate))
272 return -EINVAL;
273
274 policy_cpu = cpumask_any_and(policy->cpus, cpu_online_mask);
275 freqs.old = speedstep_get(policy_cpu);
276 freqs.new = speedstep_freqs[newstate].frequency;
277 freqs.cpu = policy->cpu;
278
279 dprintk("transiting from %u to %u kHz\n", freqs.old, freqs.new);
280
281 /* no transition necessary */
282 if (freqs.old == freqs.new)
283 return 0;
284
285 for_each_cpu(i, policy->cpus) {
286 freqs.cpu = i;
287 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
288 }
289
290 smp_call_function_single(policy_cpu, _speedstep_set_state, &newstate,
291 true);
292
293 for_each_cpu(i, policy->cpus) {
294 freqs.cpu = i;
295 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
296 }
297
298 return 0;
299 }
300
301
302 /**
303 * speedstep_verify - verifies a new CPUFreq policy
304 * @policy: new policy
305 *
306 * Limit must be within speedstep_low_freq and speedstep_high_freq, with
307 * at least one border included.
308 */
speedstep_verify(struct cpufreq_policy * policy)309 static int speedstep_verify(struct cpufreq_policy *policy)
310 {
311 return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
312 }
313
314 struct get_freqs {
315 struct cpufreq_policy *policy;
316 int ret;
317 };
318
get_freqs_on_cpu(void * _get_freqs)319 static void get_freqs_on_cpu(void *_get_freqs)
320 {
321 struct get_freqs *get_freqs = _get_freqs;
322
323 get_freqs->ret =
324 speedstep_get_freqs(speedstep_processor,
325 &speedstep_freqs[SPEEDSTEP_LOW].frequency,
326 &speedstep_freqs[SPEEDSTEP_HIGH].frequency,
327 &get_freqs->policy->cpuinfo.transition_latency,
328 &speedstep_set_state);
329 }
330
speedstep_cpu_init(struct cpufreq_policy * policy)331 static int speedstep_cpu_init(struct cpufreq_policy *policy)
332 {
333 int result;
334 unsigned int policy_cpu, speed;
335 struct get_freqs gf;
336
337 /* only run on CPU to be set, or on its sibling */
338 #ifdef CONFIG_SMP
339 cpumask_copy(policy->cpus, cpu_sibling_mask(policy->cpu));
340 #endif
341 policy_cpu = cpumask_any_and(policy->cpus, cpu_online_mask);
342
343 /* detect low and high frequency and transition latency */
344 gf.policy = policy;
345 smp_call_function_single(policy_cpu, get_freqs_on_cpu, &gf, 1);
346 if (gf.ret)
347 return gf.ret;
348
349 /* get current speed setting */
350 speed = speedstep_get(policy_cpu);
351 if (!speed)
352 return -EIO;
353
354 dprintk("currently at %s speed setting - %i MHz\n",
355 (speed == speedstep_freqs[SPEEDSTEP_LOW].frequency)
356 ? "low" : "high",
357 (speed / 1000));
358
359 /* cpuinfo and default policy values */
360 policy->cur = speed;
361
362 result = cpufreq_frequency_table_cpuinfo(policy, speedstep_freqs);
363 if (result)
364 return result;
365
366 cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu);
367
368 return 0;
369 }
370
371
speedstep_cpu_exit(struct cpufreq_policy * policy)372 static int speedstep_cpu_exit(struct cpufreq_policy *policy)
373 {
374 cpufreq_frequency_table_put_attr(policy->cpu);
375 return 0;
376 }
377
378 static struct freq_attr *speedstep_attr[] = {
379 &cpufreq_freq_attr_scaling_available_freqs,
380 NULL,
381 };
382
383
384 static struct cpufreq_driver speedstep_driver = {
385 .name = "speedstep-ich",
386 .verify = speedstep_verify,
387 .target = speedstep_target,
388 .init = speedstep_cpu_init,
389 .exit = speedstep_cpu_exit,
390 .get = speedstep_get,
391 .owner = THIS_MODULE,
392 .attr = speedstep_attr,
393 };
394
395
396 /**
397 * speedstep_init - initializes the SpeedStep CPUFreq driver
398 *
399 * Initializes the SpeedStep support. Returns -ENODEV on unsupported
400 * devices, -EINVAL on problems during initiatization, and zero on
401 * success.
402 */
speedstep_init(void)403 static int __init speedstep_init(void)
404 {
405 /* detect processor */
406 speedstep_processor = speedstep_detect_processor();
407 if (!speedstep_processor) {
408 dprintk("Intel(R) SpeedStep(TM) capable processor "
409 "not found\n");
410 return -ENODEV;
411 }
412
413 /* detect chipset */
414 if (!speedstep_detect_chipset()) {
415 dprintk("Intel(R) SpeedStep(TM) for this chipset not "
416 "(yet) available.\n");
417 return -ENODEV;
418 }
419
420 /* activate speedstep support */
421 if (speedstep_activate()) {
422 pci_dev_put(speedstep_chipset_dev);
423 return -EINVAL;
424 }
425
426 if (speedstep_find_register())
427 return -ENODEV;
428
429 return cpufreq_register_driver(&speedstep_driver);
430 }
431
432
433 /**
434 * speedstep_exit - unregisters SpeedStep support
435 *
436 * Unregisters SpeedStep support.
437 */
speedstep_exit(void)438 static void __exit speedstep_exit(void)
439 {
440 pci_dev_put(speedstep_chipset_dev);
441 cpufreq_unregister_driver(&speedstep_driver);
442 }
443
444
445 MODULE_AUTHOR("Dave Jones <davej@redhat.com>, "
446 "Dominik Brodowski <linux@brodo.de>");
447 MODULE_DESCRIPTION("Speedstep driver for Intel mobile processors on chipsets "
448 "with ICH-M southbridges.");
449 MODULE_LICENSE("GPL");
450
451 module_init(speedstep_init);
452 module_exit(speedstep_exit);
453