Merge branch 'samsung/exynos5' into next/soc2
[linux-2.6.git] / drivers / cpufreq / e_powersaver.c
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 <rafalbilski@interia.pl>");
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);