Linux Kernel  3.7.1
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
e_powersaver.c
Go to the documentation of this file.
1 /*
2  * Based on documentation provided by Dave Jones. Thanks!
3  *
4  * Licensed under the terms of the GNU GPL License version 2.
5  *
6  * BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
7  */
8 
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/init.h>
12 #include <linux/cpufreq.h>
13 #include <linux/ioport.h>
14 #include <linux/slab.h>
15 #include <linux/timex.h>
16 #include <linux/io.h>
17 #include <linux/delay.h>
18 
19 #include <asm/cpu_device_id.h>
20 #include <asm/msr.h>
21 #include <asm/tsc.h>
22 
23 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
24 #include <linux/acpi.h>
25 #include <acpi/processor.h>
26 #endif
27 
28 #define EPS_BRAND_C7M 0
29 #define EPS_BRAND_C7 1
30 #define EPS_BRAND_EDEN 2
31 #define EPS_BRAND_C3 3
32 #define EPS_BRAND_C7D 4
33 
34 struct eps_cpu_data {
35  u32 fsb;
36 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
37  u32 bios_limit;
38 #endif
39  struct cpufreq_frequency_table freq_table[];
40 };
41 
42 static struct eps_cpu_data *eps_cpu[NR_CPUS];
43 
44 /* Module parameters */
45 static int freq_failsafe_off;
46 static int voltage_failsafe_off;
47 static int set_max_voltage;
48 
49 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
50 static int ignore_acpi_limit;
51 
52 static struct acpi_processor_performance *eps_acpi_cpu_perf;
53 
54 /* Minimum necessary to get acpi_processor_get_bios_limit() working */
55 static int eps_acpi_init(void)
56 {
57  eps_acpi_cpu_perf = kzalloc(sizeof(struct acpi_processor_performance),
58  GFP_KERNEL);
59  if (!eps_acpi_cpu_perf)
60  return -ENOMEM;
61 
62  if (!zalloc_cpumask_var(&eps_acpi_cpu_perf->shared_cpu_map,
63  GFP_KERNEL)) {
64  kfree(eps_acpi_cpu_perf);
65  eps_acpi_cpu_perf = NULL;
66  return -ENOMEM;
67  }
68 
69  if (acpi_processor_register_performance(eps_acpi_cpu_perf, 0)) {
70  free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map);
71  kfree(eps_acpi_cpu_perf);
72  eps_acpi_cpu_perf = NULL;
73  return -EIO;
74  }
75  return 0;
76 }
77 
78 static int eps_acpi_exit(struct cpufreq_policy *policy)
79 {
80  if (eps_acpi_cpu_perf) {
81  acpi_processor_unregister_performance(eps_acpi_cpu_perf, 0);
82  free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map);
83  kfree(eps_acpi_cpu_perf);
84  eps_acpi_cpu_perf = NULL;
85  }
86  return 0;
87 }
88 #endif
89 
90 static unsigned int eps_get(unsigned int cpu)
91 {
92  struct eps_cpu_data *centaur;
93  u32 lo, hi;
94 
95  if (cpu)
96  return 0;
97  centaur = eps_cpu[cpu];
98  if (centaur == NULL)
99  return 0;
100 
101  /* Return current frequency */
102  rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
103  return centaur->fsb * ((lo >> 8) & 0xff);
104 }
105 
106 static int eps_set_state(struct eps_cpu_data *centaur,
107  unsigned int cpu,
108  u32 dest_state)
109 {
110  struct cpufreq_freqs freqs;
111  u32 lo, hi;
112  int err = 0;
113  int i;
114 
115  freqs.old = eps_get(cpu);
116  freqs.new = centaur->fsb * ((dest_state >> 8) & 0xff);
117  freqs.cpu = cpu;
118  cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
119 
120  /* Wait while CPU is busy */
121  rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
122  i = 0;
123  while (lo & ((1 << 16) | (1 << 17))) {
124  udelay(16);
125  rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
126  i++;
127  if (unlikely(i > 64)) {
128  err = -ENODEV;
129  goto postchange;
130  }
131  }
132  /* Set new multiplier and voltage */
133  wrmsr(MSR_IA32_PERF_CTL, dest_state & 0xffff, 0);
134  /* Wait until transition end */
135  i = 0;
136  do {
137  udelay(16);
138  rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
139  i++;
140  if (unlikely(i > 64)) {
141  err = -ENODEV;
142  goto postchange;
143  }
144  } while (lo & ((1 << 16) | (1 << 17)));
145 
146  /* Return current frequency */
147 postchange:
148  rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
149  freqs.new = centaur->fsb * ((lo >> 8) & 0xff);
150 
151 #ifdef DEBUG
152  {
153  u8 current_multiplier, current_voltage;
154 
155  /* Print voltage and multiplier */
156  rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
157  current_voltage = lo & 0xff;
158  printk(KERN_INFO "eps: Current voltage = %dmV\n",
159  current_voltage * 16 + 700);
160  current_multiplier = (lo >> 8) & 0xff;
161  printk(KERN_INFO "eps: Current multiplier = %d\n",
162  current_multiplier);
163  }
164 #endif
165  cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
166  return err;
167 }
168 
169 static int eps_target(struct cpufreq_policy *policy,
170  unsigned int target_freq,
171  unsigned int relation)
172 {
173  struct eps_cpu_data *centaur;
174  unsigned int newstate = 0;
175  unsigned int cpu = policy->cpu;
176  unsigned int dest_state;
177  int ret;
178 
179  if (unlikely(eps_cpu[cpu] == NULL))
180  return -ENODEV;
181  centaur = eps_cpu[cpu];
182 
183  if (unlikely(cpufreq_frequency_table_target(policy,
184  &eps_cpu[cpu]->freq_table[0],
185  target_freq,
186  relation,
187  &newstate))) {
188  return -EINVAL;
189  }
190 
191  /* Make frequency transition */
192  dest_state = centaur->freq_table[newstate].index & 0xffff;
193  ret = eps_set_state(centaur, cpu, dest_state);
194  if (ret)
195  printk(KERN_ERR "eps: Timeout!\n");
196  return ret;
197 }
198 
199 static int eps_verify(struct cpufreq_policy *policy)
200 {
201  return cpufreq_frequency_table_verify(policy,
202  &eps_cpu[policy->cpu]->freq_table[0]);
203 }
204 
205 static int eps_cpu_init(struct cpufreq_policy *policy)
206 {
207  unsigned int i;
208  u32 lo, hi;
209  u64 val;
210  u8 current_multiplier, current_voltage;
211  u8 max_multiplier, max_voltage;
212  u8 min_multiplier, min_voltage;
213  u8 brand = 0;
214  u32 fsb;
215  struct eps_cpu_data *centaur;
216  struct cpuinfo_x86 *c = &cpu_data(0);
217  struct cpufreq_frequency_table *f_table;
218  int k, step, voltage;
219  int ret;
220  int states;
221 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
222  unsigned int limit;
223 #endif
224 
225  if (policy->cpu != 0)
226  return -ENODEV;
227 
228  /* Check brand */
229  printk(KERN_INFO "eps: Detected VIA ");
230 
231  switch (c->x86_model) {
232  case 10:
233  rdmsr(0x1153, lo, hi);
234  brand = (((lo >> 2) ^ lo) >> 18) & 3;
235  printk(KERN_CONT "Model A ");
236  break;
237  case 13:
238  rdmsr(0x1154, lo, hi);
239  brand = (((lo >> 4) ^ (lo >> 2))) & 0x000000ff;
240  printk(KERN_CONT "Model D ");
241  break;
242  }
243 
244  switch (brand) {
245  case EPS_BRAND_C7M:
246  printk(KERN_CONT "C7-M\n");
247  break;
248  case EPS_BRAND_C7:
249  printk(KERN_CONT "C7\n");
250  break;
251  case EPS_BRAND_EDEN:
252  printk(KERN_CONT "Eden\n");
253  break;
254  case EPS_BRAND_C7D:
255  printk(KERN_CONT "C7-D\n");
256  break;
257  case EPS_BRAND_C3:
258  printk(KERN_CONT "C3\n");
259  return -ENODEV;
260  break;
261  }
262  /* Enable Enhanced PowerSaver */
263  rdmsrl(MSR_IA32_MISC_ENABLE, val);
264  if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
265  val |= MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP;
266  wrmsrl(MSR_IA32_MISC_ENABLE, val);
267  /* Can be locked at 0 */
268  rdmsrl(MSR_IA32_MISC_ENABLE, val);
269  if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
270  printk(KERN_INFO "eps: Can't enable Enhanced PowerSaver\n");
271  return -ENODEV;
272  }
273  }
274 
275  /* Print voltage and multiplier */
276  rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
277  current_voltage = lo & 0xff;
278  printk(KERN_INFO "eps: Current voltage = %dmV\n",
279  current_voltage * 16 + 700);
280  current_multiplier = (lo >> 8) & 0xff;
281  printk(KERN_INFO "eps: Current multiplier = %d\n", current_multiplier);
282 
283  /* Print limits */
284  max_voltage = hi & 0xff;
285  printk(KERN_INFO "eps: Highest voltage = %dmV\n",
286  max_voltage * 16 + 700);
287  max_multiplier = (hi >> 8) & 0xff;
288  printk(KERN_INFO "eps: Highest multiplier = %d\n", max_multiplier);
289  min_voltage = (hi >> 16) & 0xff;
290  printk(KERN_INFO "eps: Lowest voltage = %dmV\n",
291  min_voltage * 16 + 700);
292  min_multiplier = (hi >> 24) & 0xff;
293  printk(KERN_INFO "eps: Lowest multiplier = %d\n", min_multiplier);
294 
295  /* Sanity checks */
296  if (current_multiplier == 0 || max_multiplier == 0
297  || min_multiplier == 0)
298  return -EINVAL;
299  if (current_multiplier > max_multiplier
300  || max_multiplier <= min_multiplier)
301  return -EINVAL;
302  if (current_voltage > 0x1f || max_voltage > 0x1f)
303  return -EINVAL;
304  if (max_voltage < min_voltage
305  || current_voltage < min_voltage
306  || current_voltage > max_voltage)
307  return -EINVAL;
308 
309  /* Check for systems using underclocked CPU */
310  if (!freq_failsafe_off && max_multiplier != current_multiplier) {
311  printk(KERN_INFO "eps: Your processor is running at different "
312  "frequency then its maximum. Aborting.\n");
313  printk(KERN_INFO "eps: You can use freq_failsafe_off option "
314  "to disable this check.\n");
315  return -EINVAL;
316  }
317  if (!voltage_failsafe_off && max_voltage != current_voltage) {
318  printk(KERN_INFO "eps: Your processor is running at different "
319  "voltage then its maximum. Aborting.\n");
320  printk(KERN_INFO "eps: You can use voltage_failsafe_off "
321  "option to disable this check.\n");
322  return -EINVAL;
323  }
324 
325  /* Calc FSB speed */
326  fsb = cpu_khz / current_multiplier;
327 
328 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
329  /* Check for ACPI processor speed limit */
330  if (!ignore_acpi_limit && !eps_acpi_init()) {
331  if (!acpi_processor_get_bios_limit(policy->cpu, &limit)) {
332  printk(KERN_INFO "eps: ACPI limit %u.%uGHz\n",
333  limit/1000000,
334  (limit%1000000)/10000);
335  eps_acpi_exit(policy);
336  /* Check if max_multiplier is in BIOS limits */
337  if (limit && max_multiplier * fsb > limit) {
338  printk(KERN_INFO "eps: Aborting.\n");
339  return -EINVAL;
340  }
341  }
342  }
343 #endif
344 
345  /* Allow user to set lower maximum voltage then that reported
346  * by processor */
347  if (brand == EPS_BRAND_C7M && set_max_voltage) {
348  u32 v;
349 
350  /* Change mV to something hardware can use */
351  v = (set_max_voltage - 700) / 16;
352  /* Check if voltage is within limits */
353  if (v >= min_voltage && v <= max_voltage) {
354  printk(KERN_INFO "eps: Setting %dmV as maximum.\n",
355  v * 16 + 700);
356  max_voltage = v;
357  }
358  }
359 
360  /* Calc number of p-states supported */
361  if (brand == EPS_BRAND_C7M)
362  states = max_multiplier - min_multiplier + 1;
363  else
364  states = 2;
365 
366  /* Allocate private data and frequency table for current cpu */
367  centaur = kzalloc(sizeof(struct eps_cpu_data)
368  + (states + 1) * sizeof(struct cpufreq_frequency_table),
369  GFP_KERNEL);
370  if (!centaur)
371  return -ENOMEM;
372  eps_cpu[0] = centaur;
373 
374  /* Copy basic values */
375  centaur->fsb = fsb;
376 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
377  centaur->bios_limit = limit;
378 #endif
379 
380  /* Fill frequency and MSR value table */
381  f_table = &centaur->freq_table[0];
382  if (brand != EPS_BRAND_C7M) {
383  f_table[0].frequency = fsb * min_multiplier;
384  f_table[0].index = (min_multiplier << 8) | min_voltage;
385  f_table[1].frequency = fsb * max_multiplier;
386  f_table[1].index = (max_multiplier << 8) | max_voltage;
387  f_table[2].frequency = CPUFREQ_TABLE_END;
388  } else {
389  k = 0;
390  step = ((max_voltage - min_voltage) * 256)
391  / (max_multiplier - min_multiplier);
392  for (i = min_multiplier; i <= max_multiplier; i++) {
393  voltage = (k * step) / 256 + min_voltage;
394  f_table[k].frequency = fsb * i;
395  f_table[k].index = (i << 8) | voltage;
396  k++;
397  }
398  f_table[k].frequency = CPUFREQ_TABLE_END;
399  }
400 
401  policy->cpuinfo.transition_latency = 140000; /* 844mV -> 700mV in ns */
402  policy->cur = fsb * current_multiplier;
403 
404  ret = cpufreq_frequency_table_cpuinfo(policy, &centaur->freq_table[0]);
405  if (ret) {
406  kfree(centaur);
407  return ret;
408  }
409 
410  cpufreq_frequency_table_get_attr(&centaur->freq_table[0], policy->cpu);
411  return 0;
412 }
413 
414 static int eps_cpu_exit(struct cpufreq_policy *policy)
415 {
416  unsigned int cpu = policy->cpu;
417 
418  /* Bye */
419  cpufreq_frequency_table_put_attr(policy->cpu);
420  kfree(eps_cpu[cpu]);
421  eps_cpu[cpu] = NULL;
422  return 0;
423 }
424 
425 static struct freq_attr *eps_attr[] = {
426  &cpufreq_freq_attr_scaling_available_freqs,
427  NULL,
428 };
429 
430 static struct cpufreq_driver eps_driver = {
431  .verify = eps_verify,
432  .target = eps_target,
433  .init = eps_cpu_init,
434  .exit = eps_cpu_exit,
435  .get = eps_get,
436  .name = "e_powersaver",
437  .owner = THIS_MODULE,
438  .attr = eps_attr,
439 };
440 
441 
442 /* This driver will work only on Centaur C7 processors with
443  * Enhanced SpeedStep/PowerSaver registers */
444 static const struct x86_cpu_id eps_cpu_id[] = {
445  { X86_VENDOR_CENTAUR, 6, X86_MODEL_ANY, X86_FEATURE_EST },
446  {}
447 };
448 MODULE_DEVICE_TABLE(x86cpu, eps_cpu_id);
449 
450 static int __init eps_init(void)
451 {
452  if (!x86_match_cpu(eps_cpu_id) || boot_cpu_data.x86_model < 10)
453  return -ENODEV;
454  if (cpufreq_register_driver(&eps_driver))
455  return -EINVAL;
456  return 0;
457 }
458 
459 static void __exit eps_exit(void)
460 {
461  cpufreq_unregister_driver(&eps_driver);
462 }
463 
464 /* Allow user to overclock his machine or to change frequency to higher after
465  * unloading module */
466 module_param(freq_failsafe_off, int, 0644);
467 MODULE_PARM_DESC(freq_failsafe_off, "Disable current vs max frequency check");
468 module_param(voltage_failsafe_off, int, 0644);
469 MODULE_PARM_DESC(voltage_failsafe_off, "Disable current vs max voltage check");
470 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
471 module_param(ignore_acpi_limit, int, 0644);
472 MODULE_PARM_DESC(ignore_acpi_limit, "Don't check ACPI's processor speed limit");
473 #endif
474 module_param(set_max_voltage, int, 0644);
475 MODULE_PARM_DESC(set_max_voltage, "Set maximum CPU voltage (mV) C7-M only");
476 
477 MODULE_AUTHOR("Rafal Bilski <[email protected]>");
478 MODULE_DESCRIPTION("Enhanced PowerSaver driver for VIA C7 CPU's.");
479 MODULE_LICENSE("GPL");
480 
481 module_init(eps_init);
482 module_exit(eps_exit);
Generated on Thu Jan 10 2013 13:28:35 for Linux Kernel by   doxygen 1.8.2